Merge remote-tracking branch 'upstream/master' into fix-stream-compression-config-interface

330 files changed, 2305 insertions, 1132 deletions

diff --git a/src/core/lib/support/backoff.c b/src/core/lib/backoff/backoff.cc
index 6dc0df473b..fe0a751817 100644
--- a/src/core/lib/support/backoff.c
+++ b/src/core/lib/backoff/backoff.cc
@@ -16,13 +16,14 @@
  *
  */
 
-#include "src/core/lib/support/backoff.h"
+#include "src/core/lib/backoff/backoff.h"
 
 #include <grpc/support/useful.h>
 
-void gpr_backoff_init(gpr_backoff *backoff, int64_t initial_connect_timeout,
-                      double multiplier, double jitter,
-                      int64_t min_timeout_millis, int64_t max_timeout_millis) {
+void grpc_backoff_init(grpc_backoff *backoff,
+                       grpc_millis initial_connect_timeout, double multiplier,
+                       double jitter, grpc_millis min_timeout_millis,
+                       grpc_millis max_timeout_millis) {
   backoff->initial_connect_timeout = initial_connect_timeout;
   backoff->multiplier = multiplier;
   backoff->jitter = jitter;
@@ -31,11 +32,11 @@ void gpr_backoff_init(gpr_backoff *backoff, int64_t initial_connect_timeout,
   backoff->rng_state = (uint32_t)gpr_now(GPR_CLOCK_REALTIME).tv_nsec;
 }
 
-gpr_timespec gpr_backoff_begin(gpr_backoff *backoff, gpr_timespec now) {
+grpc_millis grpc_backoff_begin(grpc_exec_ctx *exec_ctx, grpc_backoff *backoff) {
   backoff->current_timeout_millis = backoff->initial_connect_timeout;
-  const int64_t first_timeout =
+  const grpc_millis first_timeout =
       GPR_MAX(backoff->current_timeout_millis, backoff->min_timeout_millis);
-  return gpr_time_add(now, gpr_time_from_millis(first_timeout, GPR_TIMESPAN));
+  return grpc_exec_ctx_now(exec_ctx) + first_timeout;
 }
 
 /* Generate a random number between 0 and 1. */
@@ -44,11 +45,11 @@ static double generate_uniform_random_number(uint32_t *rng_state) {
   return *rng_state / (double)((uint32_t)1 << 31);
 }
 
-gpr_timespec gpr_backoff_step(gpr_backoff *backoff, gpr_timespec now) {
+grpc_millis grpc_backoff_step(grpc_exec_ctx *exec_ctx, grpc_backoff *backoff) {
   const double new_timeout_millis =
       backoff->multiplier * (double)backoff->current_timeout_millis;
   backoff->current_timeout_millis =
-      GPR_MIN((int64_t)new_timeout_millis, backoff->max_timeout_millis);
+      GPR_MIN((grpc_millis)new_timeout_millis, backoff->max_timeout_millis);
 
   const double jitter_range_width = backoff->jitter * new_timeout_millis;
   const double jitter =
@@ -56,17 +57,17 @@ gpr_timespec gpr_backoff_step(gpr_backoff *backoff, gpr_timespec now) {
       jitter_range_width;
 
   backoff->current_timeout_millis =
-      (int64_t)((double)(backoff->current_timeout_millis) + jitter);
+      (grpc_millis)((double)(backoff->current_timeout_millis) + jitter);
 
-  const gpr_timespec current_deadline = gpr_time_add(
-      now, gpr_time_from_millis(backoff->current_timeout_millis, GPR_TIMESPAN));
+  const grpc_millis current_deadline =
+      grpc_exec_ctx_now(exec_ctx) + backoff->current_timeout_millis;
 
-  const gpr_timespec min_deadline = gpr_time_add(
-      now, gpr_time_from_millis(backoff->min_timeout_millis, GPR_TIMESPAN));
+  const grpc_millis min_deadline =
+      grpc_exec_ctx_now(exec_ctx) + backoff->min_timeout_millis;
 
-  return gpr_time_max(current_deadline, min_deadline);
+  return GPR_MAX(current_deadline, min_deadline);
 }
 
-void gpr_backoff_reset(gpr_backoff *backoff) {
+void grpc_backoff_reset(grpc_backoff *backoff) {
   backoff->current_timeout_millis = backoff->initial_connect_timeout;
 }
diff --git a/src/core/lib/support/backoff.h b/src/core/lib/backoff/backoff.h
index 6e0cc3a4b6..80e49ea52a 100644
--- a/src/core/lib/support/backoff.h
+++ b/src/core/lib/backoff/backoff.h
@@ -16,41 +16,51 @@
  *
  */
 
-#ifndef GRPC_CORE_LIB_SUPPORT_BACKOFF_H
-#define GRPC_CORE_LIB_SUPPORT_BACKOFF_H
+#ifndef GRPC_CORE_LIB_BACKOFF_BACKOFF_H
+#define GRPC_CORE_LIB_BACKOFF_BACKOFF_H
 
-#include <grpc/support/time.h>
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 typedef struct {
   /// const:  how long to wait after the first failure before retrying
-  int64_t initial_connect_timeout;
+  grpc_millis initial_connect_timeout;
   /// const: factor with which to multiply backoff after a failed retry
   double multiplier;
   /// const: amount to randomize backoffs
   double jitter;
   /// const: minimum time between retries in milliseconds
-  int64_t min_timeout_millis;
+  grpc_millis min_timeout_millis;
   /// const: maximum time between retries in milliseconds
-  int64_t max_timeout_millis;
+  grpc_millis max_timeout_millis;
 
   /// random number generator
   uint32_t rng_state;
 
   /// current retry timeout in milliseconds
-  int64_t current_timeout_millis;
-} gpr_backoff;
+  grpc_millis current_timeout_millis;
+} grpc_backoff;
 
 /// Initialize backoff machinery - does not need to be destroyed
-void gpr_backoff_init(gpr_backoff *backoff, int64_t initial_connect_timeout,
-                      double multiplier, double jitter,
-                      int64_t min_timeout_millis, int64_t max_timeout_millis);
+void grpc_backoff_init(grpc_backoff *backoff,
+                       grpc_millis initial_connect_timeout, double multiplier,
+                       double jitter, grpc_millis min_timeout_millis,
+                       grpc_millis max_timeout_millis);
 
 /// Begin retry loop: returns a timespec for the NEXT retry
-gpr_timespec gpr_backoff_begin(gpr_backoff *backoff, gpr_timespec now);
+grpc_millis grpc_backoff_begin(grpc_exec_ctx *exec_ctx, grpc_backoff *backoff);
 /// Step a retry loop: returns a timespec for the NEXT retry
-gpr_timespec gpr_backoff_step(gpr_backoff *backoff, gpr_timespec now);
-/// Reset the backoff, so the next gpr_backoff_step will be a gpr_backoff_begin
+grpc_millis grpc_backoff_step(grpc_exec_ctx *exec_ctx, grpc_backoff *backoff);
+/// Reset the backoff, so the next grpc_backoff_step will be a
+/// grpc_backoff_begin
 /// instead
-void gpr_backoff_reset(gpr_backoff *backoff);
+void grpc_backoff_reset(grpc_backoff *backoff);
+
+#ifdef __cplusplus
+}
+#endif
 
-#endif /* GRPC_CORE_LIB_SUPPORT_BACKOFF_H */
+#endif /* GRPC_CORE_LIB_BACKOFF_BACKOFF_H */
diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.cc
index 69980586aa..69980586aa 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/src/core/lib/channel/channel_args.cc
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index f649a8d9ec..c6a4b00a42 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/src/core/lib/channel/channel_args.h
@@ -23,6 +23,10 @@
 #include <grpc/grpc.h>
 #include "src/core/lib/iomgr/socket_mutator.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Channel args are intentionally immutable, to avoid the need for locking.
 
 /** Copy the arguments in \a src into a new instance */
@@ -118,4 +122,8 @@ grpc_arg grpc_channel_arg_integer_create(char *name, int value);
 grpc_arg grpc_channel_arg_pointer_create(char *name, void *value,
                                          const grpc_arg_pointer_vtable *vtable);
 
-#endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_CHANNEL_CHANNEL_ARGS_H */
\ No newline at end of file
diff --git a/src/core/lib/channel/channel_stack.c b/src/core/lib/channel/channel_stack.cc
index 775c8bc667..775c8bc667 100644
--- a/src/core/lib/channel/channel_stack.c
+++ b/src/core/lib/channel/channel_stack.cc
diff --git a/src/core/lib/channel/channel_stack.h b/src/core/lib/channel/channel_stack.h
index f0de80f0c0..5c00c09889 100644
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@@ -70,7 +70,7 @@ typedef struct {
   grpc_call_context_element *context;
   grpc_slice path;
   gpr_timespec start_time;
-  gpr_timespec deadline;
+  grpc_millis deadline;
   gpr_arena *arena;
   grpc_call_combiner *call_combiner;
 } grpc_call_element_args;
diff --git a/src/core/lib/channel/channel_stack_builder.c b/src/core/lib/channel/channel_stack_builder.cc
index b663ebfb52..b663ebfb52 100644
--- a/src/core/lib/channel/channel_stack_builder.c
+++ b/src/core/lib/channel/channel_stack_builder.cc
diff --git a/src/core/lib/channel/connected_channel.c b/src/core/lib/channel/connected_channel.cc
index 4f37908958..4f37908958 100644
--- a/src/core/lib/channel/connected_channel.c
+++ b/src/core/lib/channel/connected_channel.cc
diff --git a/src/core/lib/channel/connected_channel.h b/src/core/lib/channel/connected_channel.h
index 10c98cce54..b55a1089a0 100644
--- a/src/core/lib/channel/connected_channel.h
+++ b/src/core/lib/channel/connected_channel.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/channel/channel_stack_builder.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_connected_filter;
 
 bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
@@ -30,4 +34,8 @@ bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
 /* Debug helper to dig the transport stream out of a call element */
 grpc_stream *grpc_connected_channel_get_stream(grpc_call_element *elem);
 
-#endif /* GRPC_CORE_LIB_CHANNEL_CONNECTED_CHANNEL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_CHANNEL_CONNECTED_CHANNEL_H */
\ No newline at end of file
diff --git a/src/core/lib/channel/handshaker.c b/src/core/lib/channel/handshaker.cc
index 1753da5721..b27ee37e5b 100644
--- a/src/core/lib/channel/handshaker.c
+++ b/src/core/lib/channel/handshaker.cc
@@ -232,7 +232,7 @@ static void on_timeout(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
 void grpc_handshake_manager_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* mgr,
     grpc_endpoint* endpoint, const grpc_channel_args* channel_args,
-    gpr_timespec deadline, grpc_tcp_server_acceptor* acceptor,
+    grpc_millis deadline, grpc_tcp_server_acceptor* acceptor,
     grpc_iomgr_cb_func on_handshake_done, void* user_data) {
   gpr_mu_lock(&mgr->mu);
   GPR_ASSERT(mgr->index == 0);
@@ -255,9 +255,7 @@ void grpc_handshake_manager_do_handshake(
   gpr_ref(&mgr->refs);
   GRPC_CLOSURE_INIT(&mgr->on_timeout, on_timeout, mgr,
                     grpc_schedule_on_exec_ctx);
-  grpc_timer_init(exec_ctx, &mgr->deadline_timer,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  &mgr->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_timer_init(exec_ctx, &mgr->deadline_timer, deadline, &mgr->on_timeout);
   // Start first handshaker, which also owns a ref.
   gpr_ref(&mgr->refs);
   bool done = call_next_handshaker_locked(exec_ctx, mgr, GRPC_ERROR_NONE);
diff --git a/src/core/lib/channel/handshaker.h b/src/core/lib/channel/handshaker.h
index eb9a59bd08..51ee56af43 100644
--- a/src/core/lib/channel/handshaker.h
+++ b/src/core/lib/channel/handshaker.h
@@ -26,6 +26,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/tcp_server.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /// Handshakers are used to perform initial handshakes on a connection
 /// before the client sends the initial request.  Some examples of what
 /// a handshaker can be used for includes support for HTTP CONNECT on
@@ -145,7 +149,7 @@ void grpc_handshake_manager_shutdown(grpc_exec_ctx* exec_ctx,
 void grpc_handshake_manager_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* mgr,
     grpc_endpoint* endpoint, const grpc_channel_args* channel_args,
-    gpr_timespec deadline, grpc_tcp_server_acceptor* acceptor,
+    grpc_millis deadline, grpc_tcp_server_acceptor* acceptor,
     grpc_iomgr_cb_func on_handshake_done, void* user_data);
 
 /// Add \a mgr to the server side list of all pending handshake managers, the
@@ -164,4 +168,8 @@ void grpc_handshake_manager_pending_list_remove(grpc_handshake_manager** head,
 void grpc_handshake_manager_pending_list_shutdown_all(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* head, grpc_error* why);
 
-#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H */
\ No newline at end of file
diff --git a/src/core/lib/channel/handshaker_factory.c b/src/core/lib/channel/handshaker_factory.cc
index 4deb280c60..4deb280c60 100644
--- a/src/core/lib/channel/handshaker_factory.c
+++ b/src/core/lib/channel/handshaker_factory.cc
diff --git a/src/core/lib/channel/handshaker_factory.h b/src/core/lib/channel/handshaker_factory.h
index 6238e735dc..2a130de252 100644
--- a/src/core/lib/channel/handshaker_factory.h
+++ b/src/core/lib/channel/handshaker_factory.h
@@ -24,6 +24,10 @@
 #include "src/core/lib/channel/handshaker.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // A handshaker factory is used to create handshakers.
 
 typedef struct grpc_handshaker_factory grpc_handshaker_factory;
@@ -48,4 +52,8 @@ void grpc_handshaker_factory_add_handshakers(
 void grpc_handshaker_factory_destroy(
     grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory);
 
-#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_FACTORY_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_FACTORY_H */
\ No newline at end of file
diff --git a/src/core/lib/channel/handshaker_registry.c b/src/core/lib/channel/handshaker_registry.cc
index c6bc87d704..c6bc87d704 100644
--- a/src/core/lib/channel/handshaker_registry.c
+++ b/src/core/lib/channel/handshaker_registry.cc
diff --git a/src/core/lib/channel/handshaker_registry.h b/src/core/lib/channel/handshaker_registry.h
index a3b2ac1dc7..e96bf06b6a 100644
--- a/src/core/lib/channel/handshaker_registry.h
+++ b/src/core/lib/channel/handshaker_registry.h
@@ -24,6 +24,10 @@
 #include "src/core/lib/channel/handshaker_factory.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   HANDSHAKER_CLIENT = 0,
   HANDSHAKER_SERVER,
@@ -45,4 +49,8 @@ void grpc_handshakers_add(grpc_exec_ctx* exec_ctx,
                           const grpc_channel_args* args,
                           grpc_handshake_manager* handshake_mgr);
 
-#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_REGISTRY_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_REGISTRY_H */
\ No newline at end of file
diff --git a/src/core/lib/compression/algorithm_metadata.h b/src/core/lib/compression/algorithm_metadata.h
index 7db771ea74..23333ac0c4 100644
--- a/src/core/lib/compression/algorithm_metadata.h
+++ b/src/core/lib/compression/algorithm_metadata.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/compression/compression_internal.h"
 #include "src/core/lib/transport/metadata.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** Return compression algorithm based metadata value */
 grpc_slice grpc_compression_algorithm_slice(
     grpc_compression_algorithm algorithm);
@@ -56,4 +60,8 @@ grpc_message_compression_algorithm_from_slice(grpc_slice str);
 grpc_stream_compression_algorithm grpc_stream_compression_algorithm_from_slice(
     grpc_slice str);
 
-#endif /* GRPC_CORE_LIB_COMPRESSION_ALGORITHM_METADATA_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_COMPRESSION_ALGORITHM_METADATA_H */
\ No newline at end of file
diff --git a/src/core/lib/compression/compression.c b/src/core/lib/compression/compression.cc
index af2391ba10..31349a58cd 100644
--- a/src/core/lib/compression/compression.c
+++ b/src/core/lib/compression/compression.cc
@@ -94,12 +94,12 @@ grpc_compression_algorithm grpc_compression_algorithm_for_level(
             grpc_message_compression_algorithm_for_level(
                 grpc_compression_level_to_message_compression_level(level),
                 grpc_compression_bitset_to_message_bitset(accepted_encodings)),
-            0));
+            (grpc_stream_compression_algorithm)0));
     return algo;
   } else if (level <= GRPC_COMPRESS_LEVEL_STREAM_HIGH) {
     GPR_ASSERT(
         grpc_compression_algorithm_from_message_stream_compression_algorithm(
-            &algo, 0,
+            &algo, (grpc_message_compression_algorithm)0,
             grpc_stream_compression_algorithm_for_level(
                 grpc_compression_level_to_stream_compression_level(level),
                 grpc_compression_bitset_to_stream_bitset(accepted_encodings))));
diff --git a/src/core/lib/compression/compression_internal.c b/src/core/lib/compression/compression_internal.cc
index e31eb830f1..e31eb830f1 100644
--- a/src/core/lib/compression/compression_internal.c
+++ b/src/core/lib/compression/compression_internal.cc
diff --git a/src/core/lib/compression/compression_internal.h b/src/core/lib/compression/compression_internal.h
index dcd49c8c11..aab5324b67 100644
--- a/src/core/lib/compression/compression_internal.h
+++ b/src/core/lib/compression/compression_internal.h
@@ -21,6 +21,10 @@
 
 #include <grpc/impl/codegen/compression_types.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   GRPC_MESSAGE_COMPRESS_NONE = 0,
   GRPC_MESSAGE_COMPRESS_DEFLATE,
@@ -107,4 +111,8 @@ grpc_stream_compression_algorithm grpc_stream_compression_algorithm_for_level(
 int grpc_stream_compression_algorithm_parse(
     grpc_slice value, grpc_stream_compression_algorithm *algorithm);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_COMPRESSION_COMPRESSION_INTERNAL_H */
diff --git a/src/core/lib/compression/message_compress.c b/src/core/lib/compression/message_compress.cc
index d174992355..d174992355 100644
--- a/src/core/lib/compression/message_compress.c
+++ b/src/core/lib/compression/message_compress.cc
diff --git a/src/core/lib/compression/message_compress.h b/src/core/lib/compression/message_compress.h
index 2882bf7075..7c2eb99443 100644
--- a/src/core/lib/compression/message_compress.h
+++ b/src/core/lib/compression/message_compress.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/compression/compression_internal.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* compress 'input' to 'output' using 'algorithm'.
    On success, appends compressed slices to output and returns 1.
    On failure, appends uncompressed slices to output and returns 0. */
@@ -37,4 +41,8 @@ int grpc_msg_decompress(grpc_exec_ctx* exec_ctx,
                         grpc_message_compression_algorithm algorithm,
                         grpc_slice_buffer* input, grpc_slice_buffer* output);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_COMPRESSION_MESSAGE_COMPRESS_H */
diff --git a/src/core/lib/compression/stream_compression.c b/src/core/lib/compression/stream_compression.cc
index 411489f029..7faeb0d34f 100644
--- a/src/core/lib/compression/stream_compression.c
+++ b/src/core/lib/compression/stream_compression.cc
@@ -21,7 +21,7 @@
 #include "src/core/lib/compression/stream_compression.h"
 #include "src/core/lib/compression/stream_compression_gzip.h"
 
-extern const grpc_stream_compression_vtable
+extern "C" const grpc_stream_compression_vtable
     grpc_stream_compression_identity_vtable;
 
 bool grpc_stream_compress(grpc_stream_compression_context *ctx,
diff --git a/src/core/lib/compression/stream_compression.h b/src/core/lib/compression/stream_compression.h
index 6d073280fa..6ee3ac1966 100644
--- a/src/core/lib/compression/stream_compression.h
+++ b/src/core/lib/compression/stream_compression.h
@@ -26,6 +26,10 @@
 
 #include "src/core/lib/transport/static_metadata.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_stream_compression_vtable grpc_stream_compression_vtable;
 
 /* Stream compression/decompression context */
@@ -111,4 +115,8 @@ void grpc_stream_compression_context_destroy(
 int grpc_stream_compression_method_parse(
     grpc_slice value, bool is_compress, grpc_stream_compression_method *method);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/core/lib/compression/stream_compression_gzip.c b/src/core/lib/compression/stream_compression_gzip.cc
index abcbdb3a91..087b018be5 100644
--- a/src/core/lib/compression/stream_compression_gzip.c
+++ b/src/core/lib/compression/stream_compression_gzip.cc
@@ -222,7 +222,6 @@ static void grpc_stream_compression_context_destroy_gzip(
 }
 
 const grpc_stream_compression_vtable grpc_stream_compression_gzip_vtable = {
-    .compress = grpc_stream_compress_gzip,
-    .decompress = grpc_stream_decompress_gzip,
-    .context_create = grpc_stream_compression_context_create_gzip,
-    .context_destroy = grpc_stream_compression_context_destroy_gzip};
+    grpc_stream_compress_gzip, grpc_stream_decompress_gzip,
+    grpc_stream_compression_context_create_gzip,
+    grpc_stream_compression_context_destroy_gzip};
diff --git a/src/core/lib/compression/stream_compression_gzip.h b/src/core/lib/compression/stream_compression_gzip.h
index 7cf49a0de9..a3f1b0406f 100644
--- a/src/core/lib/compression/stream_compression_gzip.h
+++ b/src/core/lib/compression/stream_compression_gzip.h
@@ -21,6 +21,14 @@
 
 #include "src/core/lib/compression/stream_compression.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_stream_compression_vtable grpc_stream_compression_gzip_vtable;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/core/lib/compression/stream_compression_identity.c b/src/core/lib/compression/stream_compression_identity.cc
index 3dfcf53b85..9b2e6062e1 100644
--- a/src/core/lib/compression/stream_compression_identity.c
+++ b/src/core/lib/compression/stream_compression_identity.cc
@@ -27,7 +27,7 @@
 
 /* Singleton context used for all identity streams. */
 static grpc_stream_compression_context identity_ctx = {
-    .vtable = &grpc_stream_compression_identity_vtable};
+    &grpc_stream_compression_identity_vtable};
 
 static void grpc_stream_compression_pass_through(grpc_slice_buffer *in,
                                                  grpc_slice_buffer *out,
@@ -88,7 +88,6 @@ static void grpc_stream_compression_context_destroy_identity(
 }
 
 const grpc_stream_compression_vtable grpc_stream_compression_identity_vtable = {
-    .compress = grpc_stream_compress_identity,
-    .decompress = grpc_stream_decompress_identity,
-    .context_create = grpc_stream_compression_context_create_identity,
-    .context_destroy = grpc_stream_compression_context_destroy_identity};
+    grpc_stream_compress_identity, grpc_stream_decompress_identity,
+    grpc_stream_compression_context_create_identity,
+    grpc_stream_compression_context_destroy_identity};
diff --git a/src/core/lib/compression/stream_compression_identity.h b/src/core/lib/compression/stream_compression_identity.h
index 41926e949e..3a729fafad 100644
--- a/src/core/lib/compression/stream_compression_identity.h
+++ b/src/core/lib/compression/stream_compression_identity.h
@@ -21,7 +21,15 @@
 
 #include "src/core/lib/compression/stream_compression.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_stream_compression_vtable
     grpc_stream_compression_identity_vtable;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/core/lib/debug/stats.c b/src/core/lib/debug/stats.cc
index 4096384dd9..4096384dd9 100644
--- a/src/core/lib/debug/stats.c
+++ b/src/core/lib/debug/stats.cc
diff --git a/src/core/lib/debug/stats.h b/src/core/lib/debug/stats.h
index 09d190d488..fec1d651e6 100644
--- a/src/core/lib/debug/stats.h
+++ b/src/core/lib/debug/stats.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/debug/stats_data.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_stats_data {
   gpr_atm counters[GRPC_STATS_COUNTER_COUNT];
   gpr_atm histograms[GRPC_STATS_HISTOGRAM_BUCKETS];
@@ -58,4 +62,8 @@ double grpc_stats_histo_percentile(const grpc_stats_data *data,
 size_t grpc_stats_histo_count(const grpc_stats_data *data,
                               grpc_stats_histograms histogram);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/core/lib/debug/stats_data.c b/src/core/lib/debug/stats_data.cc
index fb6055f795..5bd7884e28 100644
--- a/src/core/lib/debug/stats_data.c
+++ b/src/core/lib/debug/stats_data.cc
@@ -77,6 +77,7 @@ const char *grpc_stats_counter_name[GRPC_STATS_COUNTER_COUNT] = {
     "http2_initiate_write_due_to_transport_flow_control_unstalled",
     "http2_initiate_write_due_to_ping_response",
     "http2_initiate_write_due_to_force_rst_stream",
+    "http2_spurious_writes_begun",
     "hpack_recv_indexed",
     "hpack_recv_lithdr_incidx",
     "hpack_recv_lithdr_incidx_v",
@@ -109,8 +110,6 @@ const char *grpc_stats_counter_name[GRPC_STATS_COUNTER_COUNT] = {
     "executor_wakeup_initiated",
     "executor_queue_drained",
     "executor_push_retries",
-    "executor_threads_created",
-    "executor_threads_used",
     "server_requested_calls",
     "server_slowpath_requests_queued",
 };
@@ -179,6 +178,7 @@ const char *grpc_stats_counter_doc[GRPC_STATS_COUNTER_COUNT] = {
     "'transport_flow_control_unstalled'",
     "Number of HTTP2 writes initiated due to 'ping_response'",
     "Number of HTTP2 writes initiated due to 'force_rst_stream'",
+    "Number of HTTP2 writes initiated with nothing to write",
     "Number of HPACK indexed fields received",
     "Number of HPACK literal headers received with incremental indexing",
     "Number of HPACK literal headers received with incremental indexing and "
@@ -219,8 +219,6 @@ const char *grpc_stats_counter_doc[GRPC_STATS_COUNTER_COUNT] = {
     "Number of times an executor queue was drained",
     "Number of times we raced and were forced to retry pushing a closure to "
     "the executor",
-    "Size of the backing thread pool for overflow gRPC Core work",
-    "How many executor threads actually got used",
     "How many calls were requested (not necessarily received) by the server",
     "How many times was the server slow path taken (indicates too few "
     "outstanding requests)",
@@ -238,7 +236,6 @@ const char *grpc_stats_histogram_name[GRPC_STATS_HISTOGRAM_COUNT] = {
     "http2_send_message_per_write",
     "http2_send_trailing_metadata_per_write",
     "http2_send_flowctl_per_write",
-    "executor_closures_per_wakeup",
     "server_cqs_checked",
 };
 const char *grpc_stats_histogram_doc[GRPC_STATS_HISTOGRAM_COUNT] = {
@@ -254,7 +251,6 @@ const char *grpc_stats_histogram_doc[GRPC_STATS_HISTOGRAM_COUNT] = {
     "Number of streams whose payload was written per TCP write",
     "Number of streams terminated per TCP write",
     "Number of flow control updates written per TCP write",
-    "Number of closures executed each time an executor wakes up",
     "How many completion queues were checked looking for a CQ that had "
     "requested the incoming call",
 };
@@ -326,7 +322,6 @@ const uint8_t grpc_stats_table_7[102] = {
 const int grpc_stats_table_8[9] = {0, 1, 2, 4, 7, 13, 23, 39, 64};
 const uint8_t grpc_stats_table_9[9] = {0, 0, 1, 2, 2, 3, 4, 4, 5};
 void grpc_stats_inc_call_initial_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 262144);
   if (value < 6) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_CALL_INITIAL_SIZE,
@@ -352,7 +347,6 @@ void grpc_stats_inc_call_initial_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_0, 64));
 }
 void grpc_stats_inc_poll_events_returned(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 29) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -379,7 +373,6 @@ void grpc_stats_inc_poll_events_returned(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_2, 128));
 }
 void grpc_stats_inc_tcp_write_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_WRITE_SIZE,
@@ -405,7 +398,6 @@ void grpc_stats_inc_tcp_write_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_4, 64));
 }
 void grpc_stats_inc_tcp_write_iov_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -431,7 +423,6 @@ void grpc_stats_inc_tcp_write_iov_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_6, 64));
 }
 void grpc_stats_inc_tcp_read_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_READ_SIZE,
@@ -457,7 +448,6 @@ void grpc_stats_inc_tcp_read_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_4, 64));
 }
 void grpc_stats_inc_tcp_read_offer(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_READ_OFFER,
@@ -484,7 +474,6 @@ void grpc_stats_inc_tcp_read_offer(grpc_exec_ctx *exec_ctx, int value) {
 }
 void grpc_stats_inc_tcp_read_offer_iov_size(grpc_exec_ctx *exec_ctx,
                                             int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -512,7 +501,6 @@ void grpc_stats_inc_tcp_read_offer_iov_size(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_message_size(grpc_exec_ctx *exec_ctx,
                                             int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -540,7 +528,6 @@ void grpc_stats_inc_http2_send_message_size(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_initial_metadata_per_write(
     grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -570,7 +557,6 @@ void grpc_stats_inc_http2_send_initial_metadata_per_write(
 }
 void grpc_stats_inc_http2_send_message_per_write(grpc_exec_ctx *exec_ctx,
                                                  int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -598,7 +584,6 @@ void grpc_stats_inc_http2_send_message_per_write(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_trailing_metadata_per_write(
     grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -628,7 +613,6 @@ void grpc_stats_inc_http2_send_trailing_metadata_per_write(
 }
 void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                                                  int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -654,36 +638,7 @@ void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                            grpc_stats_histo_find_bucket_slow(
                                (exec_ctx), value, grpc_stats_table_6, 64));
 }
-void grpc_stats_inc_executor_closures_per_wakeup(grpc_exec_ctx *exec_ctx,
-                                                 int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
-  value = GPR_CLAMP(value, 0, 1024);
-  if (value < 13) {
-    GRPC_STATS_INC_HISTOGRAM(
-        (exec_ctx), GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP, value);
-    return;
-  }
-  union {
-    double dbl;
-    uint64_t uint;
-  } _val, _bkt;
-  _val.dbl = value;
-  if (_val.uint < 4637863191261478912ull) {
-    int bucket =
-        grpc_stats_table_7[((_val.uint - 4623507967449235456ull) >> 48)] + 13;
-    _bkt.dbl = grpc_stats_table_6[bucket];
-    bucket -= (_val.uint < _bkt.uint);
-    GRPC_STATS_INC_HISTOGRAM(
-        (exec_ctx), GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP, bucket);
-    return;
-  }
-  GRPC_STATS_INC_HISTOGRAM((exec_ctx),
-                           GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP,
-                           grpc_stats_histo_find_bucket_slow(
-                               (exec_ctx), value, grpc_stats_table_6, 64));
-}
 void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 64);
   if (value < 3) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -708,17 +663,17 @@ void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int value) {
                            grpc_stats_histo_find_bucket_slow(
                                (exec_ctx), value, grpc_stats_table_8, 8));
 }
-const int grpc_stats_histo_buckets[14] = {64, 128, 64, 64, 64, 64, 64,
-                                          64, 64,  64, 64, 64, 64, 8};
-const int grpc_stats_histo_start[14] = {0,   64,  192, 256, 320, 384, 448,
-                                        512, 576, 640, 704, 768, 832, 896};
-const int *const grpc_stats_histo_bucket_boundaries[14] = {
+const int grpc_stats_histo_buckets[13] = {64, 128, 64, 64, 64, 64, 64,
+                                          64, 64,  64, 64, 64, 8};
+const int grpc_stats_histo_start[13] = {0,   64,  192, 256, 320, 384, 448,
+                                        512, 576, 640, 704, 768, 832};
+const int *const grpc_stats_histo_bucket_boundaries[13] = {
     grpc_stats_table_0, grpc_stats_table_2, grpc_stats_table_4,
     grpc_stats_table_6, grpc_stats_table_4, grpc_stats_table_4,
     grpc_stats_table_6, grpc_stats_table_4, grpc_stats_table_6,
     grpc_stats_table_6, grpc_stats_table_6, grpc_stats_table_6,
-    grpc_stats_table_6, grpc_stats_table_8};
-void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx, int x) = {
+    grpc_stats_table_8};
+void (*const grpc_stats_inc_histogram[13])(grpc_exec_ctx *exec_ctx, int x) = {
     grpc_stats_inc_call_initial_size,
     grpc_stats_inc_poll_events_returned,
     grpc_stats_inc_tcp_write_size,
@@ -731,5 +686,4 @@ void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx, int x) = {
     grpc_stats_inc_http2_send_message_per_write,
     grpc_stats_inc_http2_send_trailing_metadata_per_write,
     grpc_stats_inc_http2_send_flowctl_per_write,
-    grpc_stats_inc_executor_closures_per_wakeup,
     grpc_stats_inc_server_cqs_checked};
diff --git a/src/core/lib/debug/stats_data.h b/src/core/lib/debug/stats_data.h
index 6c0ad30543..d8e4e7d264 100644
--- a/src/core/lib/debug/stats_data.h
+++ b/src/core/lib/debug/stats_data.h
@@ -24,6 +24,10 @@
 #include <inttypes.h>
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   GRPC_STATS_COUNTER_CLIENT_CALLS_CREATED,
   GRPC_STATS_COUNTER_SERVER_CALLS_CREATED,
@@ -79,6 +83,7 @@ typedef enum {
   GRPC_STATS_COUNTER_HTTP2_INITIATE_WRITE_DUE_TO_TRANSPORT_FLOW_CONTROL_UNSTALLED,
   GRPC_STATS_COUNTER_HTTP2_INITIATE_WRITE_DUE_TO_PING_RESPONSE,
   GRPC_STATS_COUNTER_HTTP2_INITIATE_WRITE_DUE_TO_FORCE_RST_STREAM,
+  GRPC_STATS_COUNTER_HTTP2_SPURIOUS_WRITES_BEGUN,
   GRPC_STATS_COUNTER_HPACK_RECV_INDEXED,
   GRPC_STATS_COUNTER_HPACK_RECV_LITHDR_INCIDX,
   GRPC_STATS_COUNTER_HPACK_RECV_LITHDR_INCIDX_V,
@@ -111,8 +116,6 @@ typedef enum {
   GRPC_STATS_COUNTER_EXECUTOR_WAKEUP_INITIATED,
   GRPC_STATS_COUNTER_EXECUTOR_QUEUE_DRAINED,
   GRPC_STATS_COUNTER_EXECUTOR_PUSH_RETRIES,
-  GRPC_STATS_COUNTER_EXECUTOR_THREADS_CREATED,
-  GRPC_STATS_COUNTER_EXECUTOR_THREADS_USED,
   GRPC_STATS_COUNTER_SERVER_REQUESTED_CALLS,
   GRPC_STATS_COUNTER_SERVER_SLOWPATH_REQUESTS_QUEUED,
   GRPC_STATS_COUNTER_COUNT
@@ -132,7 +135,6 @@ typedef enum {
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_MESSAGE_PER_WRITE,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_TRAILING_METADATA_PER_WRITE,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP,
   GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED,
   GRPC_STATS_HISTOGRAM_COUNT
 } grpc_stats_histograms;
@@ -163,11 +165,9 @@ typedef enum {
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_TRAILING_METADATA_PER_WRITE_BUCKETS = 64,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE_FIRST_SLOT = 768,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE_BUCKETS = 64,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP_FIRST_SLOT = 832,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP_BUCKETS = 64,
-  GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_FIRST_SLOT = 896,
+  GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_FIRST_SLOT = 832,
   GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_BUCKETS = 8,
-  GRPC_STATS_HISTOGRAM_BUCKETS = 904
+  GRPC_STATS_HISTOGRAM_BUCKETS = 840
 } grpc_stats_histogram_constants;
 #define GRPC_STATS_INC_CLIENT_CALLS_CREATED(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_CLIENT_CALLS_CREATED)
@@ -331,6 +331,9 @@ typedef enum {
   GRPC_STATS_INC_COUNTER(                                                     \
       (exec_ctx),                                                             \
       GRPC_STATS_COUNTER_HTTP2_INITIATE_WRITE_DUE_TO_FORCE_RST_STREAM)
+#define GRPC_STATS_INC_HTTP2_SPURIOUS_WRITES_BEGUN(exec_ctx) \
+  GRPC_STATS_INC_COUNTER((exec_ctx),                         \
+                         GRPC_STATS_COUNTER_HTTP2_SPURIOUS_WRITES_BEGUN)
 #define GRPC_STATS_INC_HPACK_RECV_INDEXED(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_HPACK_RECV_INDEXED)
 #define GRPC_STATS_INC_HPACK_RECV_LITHDR_INCIDX(exec_ctx) \
@@ -417,11 +420,6 @@ typedef enum {
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_QUEUE_DRAINED)
 #define GRPC_STATS_INC_EXECUTOR_PUSH_RETRIES(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_PUSH_RETRIES)
-#define GRPC_STATS_INC_EXECUTOR_THREADS_CREATED(exec_ctx) \
-  GRPC_STATS_INC_COUNTER((exec_ctx),                      \
-                         GRPC_STATS_COUNTER_EXECUTOR_THREADS_CREATED)
-#define GRPC_STATS_INC_EXECUTOR_THREADS_USED(exec_ctx) \
-  GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_THREADS_USED)
 #define GRPC_STATS_INC_SERVER_REQUESTED_CALLS(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_SERVER_REQUESTED_CALLS)
 #define GRPC_STATS_INC_SERVER_SLOWPATH_REQUESTS_QUEUED(exec_ctx) \
@@ -468,17 +466,17 @@ void grpc_stats_inc_http2_send_trailing_metadata_per_write(
   grpc_stats_inc_http2_send_flowctl_per_write((exec_ctx), (int)(value))
 void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                                                  int x);
-#define GRPC_STATS_INC_EXECUTOR_CLOSURES_PER_WAKEUP(exec_ctx, value) \
-  grpc_stats_inc_executor_closures_per_wakeup((exec_ctx), (int)(value))
-void grpc_stats_inc_executor_closures_per_wakeup(grpc_exec_ctx *exec_ctx,
-                                                 int x);
 #define GRPC_STATS_INC_SERVER_CQS_CHECKED(exec_ctx, value) \
   grpc_stats_inc_server_cqs_checked((exec_ctx), (int)(value))
 void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int x);
-extern const int grpc_stats_histo_buckets[14];
-extern const int grpc_stats_histo_start[14];
-extern const int *const grpc_stats_histo_bucket_boundaries[14];
-extern void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx,
+extern const int grpc_stats_histo_buckets[13];
+extern const int grpc_stats_histo_start[13];
+extern const int *const grpc_stats_histo_bucket_boundaries[13];
+extern void (*const grpc_stats_inc_histogram[13])(grpc_exec_ctx *exec_ctx,
                                                   int x);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_DEBUG_STATS_DATA_H */
diff --git a/src/core/lib/debug/stats_data.yaml b/src/core/lib/debug/stats_data.yaml
index de575f01c7..5c0ab2262e 100644
--- a/src/core/lib/debug/stats_data.yaml
+++ b/src/core/lib/debug/stats_data.yaml
@@ -189,6 +189,8 @@
   doc: Number of HTTP2 writes initiated due to 'ping_response'
 - counter: http2_initiate_write_due_to_force_rst_stream
   doc: Number of HTTP2 writes initiated due to 'force_rst_stream'
+- counter: http2_spurious_writes_begun
+  doc: Number of HTTP2 writes initiated with nothing to write
 - counter: hpack_recv_indexed
   doc: Number of HPACK indexed fields received
 - counter: hpack_recv_lithdr_incidx
@@ -259,14 +261,6 @@
 - counter: executor_push_retries
   doc: Number of times we raced and were forced to retry pushing a closure to
        the executor
-- counter: executor_threads_created
-  doc: Size of the backing thread pool for overflow gRPC Core work
-- counter: executor_threads_used
-  doc: How many executor threads actually got used
-- histogram: executor_closures_per_wakeup
-  max: 1024
-  buckets: 64
-  doc: Number of closures executed each time an executor wakes up
 # server
 - counter: server_requested_calls
   doc: How many calls were requested (not necessarily received) by the server
@@ -278,3 +272,4 @@
 - counter: server_slowpath_requests_queued
   doc: How many times was the server slow path taken (indicates too few
        outstanding requests)
+
diff --git a/src/core/lib/debug/stats_data_bq_schema.sql b/src/core/lib/debug/stats_data_bq_schema.sql
index 0611ccaff0..54869977b0 100644
--- a/src/core/lib/debug/stats_data_bq_schema.sql
+++ b/src/core/lib/debug/stats_data_bq_schema.sql
@@ -52,6 +52,7 @@ http2_initiate_write_due_to_keepalive_ping_per_iteration:FLOAT,
 http2_initiate_write_due_to_transport_flow_control_unstalled_per_iteration:FLOAT,
 http2_initiate_write_due_to_ping_response_per_iteration:FLOAT,
 http2_initiate_write_due_to_force_rst_stream_per_iteration:FLOAT,
+http2_spurious_writes_begun_per_iteration:FLOAT,
 hpack_recv_indexed_per_iteration:FLOAT,
 hpack_recv_lithdr_incidx_per_iteration:FLOAT,
 hpack_recv_lithdr_incidx_v_per_iteration:FLOAT,
@@ -84,7 +85,5 @@ executor_scheduled_to_self_per_iteration:FLOAT,
 executor_wakeup_initiated_per_iteration:FLOAT,
 executor_queue_drained_per_iteration:FLOAT,
 executor_push_retries_per_iteration:FLOAT,
-executor_threads_created_per_iteration:FLOAT,
-executor_threads_used_per_iteration:FLOAT,
 server_requested_calls_per_iteration:FLOAT,
 server_slowpath_requests_queued_per_iteration:FLOAT
diff --git a/src/core/lib/debug/trace.c b/src/core/lib/debug/trace.cc
index 7cb2789a19..21b0d8c3a6 100644
--- a/src/core/lib/debug/trace.c
+++ b/src/core/lib/debug/trace.cc
@@ -20,6 +20,7 @@
 
 #include <string.h>
 
+#include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include "src/core/lib/support/env.h"
diff --git a/src/core/lib/debug/trace.h b/src/core/lib/debug/trace.h
index 64f2e3fc33..558ba942bb 100644
--- a/src/core/lib/debug/trace.h
+++ b/src/core/lib/debug/trace.h
@@ -23,6 +23,10 @@
 #include <grpc/support/port_platform.h>
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if defined(__has_feature)
 #if __has_feature(thread_sanitizer)
 #define GRPC_THREADSAFE_TRACER
@@ -52,4 +56,8 @@ void grpc_register_tracer(grpc_tracer_flag *flag);
 void grpc_tracer_init(const char *env_var_name);
 void grpc_tracer_shutdown(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_DEBUG_TRACE_H */
diff --git a/src/core/lib/http/format_request.c b/src/core/lib/http/format_request.cc
index 88fb0ab0b6..88fb0ab0b6 100644
--- a/src/core/lib/http/format_request.c
+++ b/src/core/lib/http/format_request.cc
diff --git a/src/core/lib/http/format_request.h b/src/core/lib/http/format_request.h
index 12b42e42fa..a559aac660 100644
--- a/src/core/lib/http/format_request.h
+++ b/src/core/lib/http/format_request.h
@@ -22,6 +22,10 @@
 #include <grpc/slice.h>
 #include "src/core/lib/http/httpcli.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_slice grpc_httpcli_format_get_request(const grpc_httpcli_request *request);
 grpc_slice grpc_httpcli_format_post_request(const grpc_httpcli_request *request,
                                             const char *body_bytes,
@@ -29,4 +33,8 @@ grpc_slice grpc_httpcli_format_post_request(const grpc_httpcli_request *request,
 grpc_slice grpc_httpcli_format_connect_request(
     const grpc_httpcli_request *request);
 
-#endif /* GRPC_CORE_LIB_HTTP_FORMAT_REQUEST_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_HTTP_FORMAT_REQUEST_H */
\ No newline at end of file
diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.cc
index db995943a9..c96800b85c 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.cc
@@ -44,7 +44,7 @@ typedef struct {
   grpc_endpoint *ep;
   char *host;
   char *ssl_host_override;
-  gpr_timespec deadline;
+  grpc_millis deadline;
   int have_read_byte;
   const grpc_httpcli_handshaker *handshaker;
   grpc_closure *on_done;
@@ -65,7 +65,7 @@ static grpc_httpcli_post_override g_post_override = NULL;
 
 static void plaintext_handshake(grpc_exec_ctx *exec_ctx, void *arg,
                                 grpc_endpoint *endpoint, const char *host,
-                                gpr_timespec deadline,
+                                grpc_millis deadline,
                                 void (*on_done)(grpc_exec_ctx *exec_ctx,
                                                 void *arg,
                                                 grpc_endpoint *endpoint)) {
@@ -240,7 +240,7 @@ static void internal_request_begin(grpc_exec_ctx *exec_ctx,
                                    grpc_polling_entity *pollent,
                                    grpc_resource_quota *resource_quota,
                                    const grpc_httpcli_request *request,
-                                   gpr_timespec deadline, grpc_closure *on_done,
+                                   grpc_millis deadline, grpc_closure *on_done,
                                    grpc_httpcli_response *response,
                                    const char *name, grpc_slice request_text) {
   internal_request *req =
@@ -278,9 +278,8 @@ static void internal_request_begin(grpc_exec_ctx *exec_ctx,
 void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
                       grpc_polling_entity *pollent,
                       grpc_resource_quota *resource_quota,
-                      const grpc_httpcli_request *request,
-                      gpr_timespec deadline, grpc_closure *on_done,
-                      grpc_httpcli_response *response) {
+                      const grpc_httpcli_request *request, grpc_millis deadline,
+                      grpc_closure *on_done, grpc_httpcli_response *response) {
   char *name;
   if (g_get_override &&
       g_get_override(exec_ctx, request, deadline, on_done, response)) {
@@ -298,7 +297,7 @@ void grpc_httpcli_post(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
                        grpc_resource_quota *resource_quota,
                        const grpc_httpcli_request *request,
                        const char *body_bytes, size_t body_size,
-                       gpr_timespec deadline, grpc_closure *on_done,
+                       grpc_millis deadline, grpc_closure *on_done,
                        grpc_httpcli_response *response) {
   char *name;
   if (g_post_override &&
diff --git a/src/core/lib/http/httpcli.h b/src/core/lib/http/httpcli.h
index 809618695e..3e6bdc0e46 100644
--- a/src/core/lib/http/httpcli.h
+++ b/src/core/lib/http/httpcli.h
@@ -32,6 +32,10 @@
 /* User agent this library reports */
 #define GRPC_HTTPCLI_USER_AGENT "grpc-httpcli/0.0"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Tracks in-progress http requests
    TODO(ctiller): allow caching and capturing multiple requests for the
                   same content and combining them */
@@ -42,7 +46,7 @@ typedef struct grpc_httpcli_context {
 typedef struct {
   const char *default_port;
   void (*handshake)(grpc_exec_ctx *exec_ctx, void *arg, grpc_endpoint *endpoint,
-                    const char *host, gpr_timespec deadline,
+                    const char *host, grpc_millis deadline,
                     void (*on_done)(grpc_exec_ctx *exec_ctx, void *arg,
                                     grpc_endpoint *endpoint));
 } grpc_httpcli_handshaker;
@@ -83,8 +87,8 @@ void grpc_httpcli_context_destroy(grpc_exec_ctx *exec_ctx,
 void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
                       grpc_polling_entity *pollent,
                       grpc_resource_quota *resource_quota,
-                      const grpc_httpcli_request *request,
-                      gpr_timespec deadline, grpc_closure *on_complete,
+                      const grpc_httpcli_request *request, grpc_millis deadline,
+                      grpc_closure *on_complete,
                       grpc_httpcli_response *response);
 
 /* Asynchronously perform a HTTP POST.
@@ -106,21 +110,25 @@ void grpc_httpcli_post(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
                        grpc_resource_quota *resource_quota,
                        const grpc_httpcli_request *request,
                        const char *body_bytes, size_t body_size,
-                       gpr_timespec deadline, grpc_closure *on_complete,
+                       grpc_millis deadline, grpc_closure *on_complete,
                        grpc_httpcli_response *response);
 
 /* override functions return 1 if they handled the request, 0 otherwise */
 typedef int (*grpc_httpcli_get_override)(grpc_exec_ctx *exec_ctx,
                                          const grpc_httpcli_request *request,
-                                         gpr_timespec deadline,
+                                         grpc_millis deadline,
                                          grpc_closure *on_complete,
                                          grpc_httpcli_response *response);
 typedef int (*grpc_httpcli_post_override)(
     grpc_exec_ctx *exec_ctx, const grpc_httpcli_request *request,
-    const char *body_bytes, size_t body_size, gpr_timespec deadline,
+    const char *body_bytes, size_t body_size, grpc_millis deadline,
     grpc_closure *on_complete, grpc_httpcli_response *response);
 
 void grpc_httpcli_set_override(grpc_httpcli_get_override get,
                                grpc_httpcli_post_override post);
 
-#endif /* GRPC_CORE_LIB_HTTP_HTTPCLI_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_HTTP_HTTPCLI_H */
\ No newline at end of file
diff --git a/src/core/lib/http/httpcli_security_connector.c b/src/core/lib/http/httpcli_security_connector.cc
index c553fa3981..ef6c4a509b 100644
--- a/src/core/lib/http/httpcli_security_connector.c
+++ b/src/core/lib/http/httpcli_security_connector.cc
@@ -106,7 +106,8 @@ static grpc_security_status httpcli_ssl_channel_security_connector_create(
     return GRPC_SECURITY_ERROR;
   }
 
-  c = gpr_zalloc(sizeof(grpc_httpcli_ssl_channel_security_connector));
+  c = (grpc_httpcli_ssl_channel_security_connector *)gpr_zalloc(
+      sizeof(grpc_httpcli_ssl_channel_security_connector));
 
   gpr_ref_init(&c->base.base.refcount, 1);
   c->base.base.vtable = &httpcli_ssl_vtable;
@@ -137,8 +138,8 @@ typedef struct {
 
 static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
                               grpc_error *error) {
-  grpc_handshaker_args *args = arg;
-  on_done_closure *c = args->user_data;
+  grpc_handshaker_args *args = (grpc_handshaker_args *)arg;
+  on_done_closure *c = (on_done_closure *)args->user_data;
   if (error != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(error);
     gpr_log(GPR_ERROR, "Secure transport setup failed: %s", msg);
@@ -156,10 +157,10 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
 
 static void ssl_handshake(grpc_exec_ctx *exec_ctx, void *arg,
                           grpc_endpoint *tcp, const char *host,
-                          gpr_timespec deadline,
+                          grpc_millis deadline,
                           void (*on_done)(grpc_exec_ctx *exec_ctx, void *arg,
                                           grpc_endpoint *endpoint)) {
-  on_done_closure *c = gpr_malloc(sizeof(*c));
+  on_done_closure *c = (on_done_closure *)gpr_malloc(sizeof(*c));
   const char *pem_root_certs = grpc_get_default_ssl_roots();
   if (pem_root_certs == NULL) {
     gpr_log(GPR_ERROR, "Could not get default pem root certs.");
diff --git a/src/core/lib/http/parser.c b/src/core/lib/http/parser.cc
index 0950bd655e..0950bd655e 100644
--- a/src/core/lib/http/parser.c
+++ b/src/core/lib/http/parser.cc
diff --git a/src/core/lib/http/parser.h b/src/core/lib/http/parser.h
index c8dced3901..5484948bea 100644
--- a/src/core/lib/http/parser.h
+++ b/src/core/lib/http/parser.h
@@ -27,6 +27,10 @@
 /* Maximum length of a header string of the form 'Key: Value\r\n' */
 #define GRPC_HTTP_PARSER_MAX_HEADER_LENGTH 4096
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* A single header to be passed in a request */
 typedef struct grpc_http_header {
   char *key;
@@ -109,4 +113,8 @@ void grpc_http_response_destroy(grpc_http_response *response);
 
 extern grpc_tracer_flag grpc_http1_trace;
 
-#endif /* GRPC_CORE_LIB_HTTP_PARSER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_HTTP_PARSER_H */
\ No newline at end of file
diff --git a/src/core/lib/support/block_annotate.h b/src/core/lib/iomgr/block_annotate.h
index 8e3ef7df65..fcbfe9eb1a 100644
--- a/src/core/lib/support/block_annotate.h
+++ b/src/core/lib/iomgr/block_annotate.h
@@ -16,8 +16,8 @@
  *
  */
 
-#ifndef GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H
-#define GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H
+#ifndef GRPC_CORE_LIB_IOMGR_BLOCK_ANNOTATE_H
+#define GRPC_CORE_LIB_IOMGR_BLOCK_ANNOTATE_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -39,17 +39,26 @@ void gpr_thd_end_blocking_region();
   do {                                        \
     gpr_thd_start_blocking_region();          \
   } while (0)
-#define GRPC_SCHEDULING_END_BLOCKING_REGION \
-  do {                                      \
-    gpr_thd_end_blocking_region();          \
+#define GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX \
+  do {                                                  \
+    gpr_thd_end_blocking_region();                      \
+  } while (0)
+#define GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(ec) \
+  do {                                                        \
+    gpr_thd_end_blocking_region();                            \
+    grpc_exec_ctx_invalidate_now((ec));                       \
   } while (0)
 #else
 #define GRPC_SCHEDULING_START_BLOCKING_REGION \
   do {                                        \
   } while (0)
-#define GRPC_SCHEDULING_END_BLOCKING_REGION \
-  do {                                      \
+#define GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX \
+  do {                                                  \
+  } while (0)
+#define GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(ec) \
+  do {                                                        \
+    grpc_exec_ctx_invalidate_now((ec));                       \
   } while (0)
 #endif
 
-#endif /* GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H */
+#endif /* GRPC_CORE_LIB_IOMGR_BLOCK_ANNOTATE_H */
diff --git a/src/core/lib/iomgr/call_combiner.c b/src/core/lib/iomgr/call_combiner.cc
index 48d8eaec18..bab3df021a 100644
--- a/src/core/lib/iomgr/call_combiner.c
+++ b/src/core/lib/iomgr/call_combiner.cc
@@ -18,6 +18,8 @@
 
 #include "src/core/lib/iomgr/call_combiner.h"
 
+#include <inttypes.h>
+
 #include <grpc/support/log.h>
 
 grpc_tracer_flag grpc_call_combiner_trace =
diff --git a/src/core/lib/iomgr/call_combiner.h b/src/core/lib/iomgr/call_combiner.h
index 5cfb3f0c07..527f84fce0 100644
--- a/src/core/lib/iomgr/call_combiner.h
+++ b/src/core/lib/iomgr/call_combiner.h
@@ -27,6 +27,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/support/mpscq.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // A simple, lock-free mechanism for serializing activity related to a
 // single call.  This is similar to a combiner but is more lightweight.
 //
@@ -118,4 +122,8 @@ void grpc_call_combiner_cancel(grpc_exec_ctx* exec_ctx,
                                grpc_call_combiner* call_combiner,
                                grpc_error* error);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_CALL_COMBINER_H */
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.cc
index 00edefc6ae..00edefc6ae 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.cc
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.cc
index f899b25f10..0e707ef839 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.cc
@@ -19,6 +19,7 @@
 #include "src/core/lib/iomgr/combiner.h"
 
 #include <assert.h>
+#include <inttypes.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
diff --git a/src/core/lib/iomgr/combiner.h b/src/core/lib/iomgr/combiner.h
index 8e0434369d..10e5fb480d 100644
--- a/src/core/lib/iomgr/combiner.h
+++ b/src/core/lib/iomgr/combiner.h
@@ -26,6 +26,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/support/mpscq.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Provides serialized access to some resource.
 // Each action queued on a combiner is executed serially in a borrowed thread.
 // The actual thread executing actions may change over time (but there will only
@@ -63,4 +67,8 @@ bool grpc_combiner_continue_exec_ctx(grpc_exec_ctx *exec_ctx);
 
 extern grpc_tracer_flag grpc_combiner_trace;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_COMBINER_H */
diff --git a/src/core/lib/iomgr/endpoint.c b/src/core/lib/iomgr/endpoint.cc
index 37cce335ca..37cce335ca 100644
--- a/src/core/lib/iomgr/endpoint.c
+++ b/src/core/lib/iomgr/endpoint.cc
diff --git a/src/core/lib/iomgr/endpoint.h b/src/core/lib/iomgr/endpoint.h
index 8f0523a981..16ff0ab733 100644
--- a/src/core/lib/iomgr/endpoint.h
+++ b/src/core/lib/iomgr/endpoint.h
@@ -26,6 +26,10 @@
 #include "src/core/lib/iomgr/pollset_set.h"
 #include "src/core/lib/iomgr/resource_quota.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* An endpoint caps a streaming channel between two communicating processes.
    Examples may be: a tcp socket, <stdin+stdout>, or some shared memory. */
 
@@ -95,4 +99,8 @@ struct grpc_endpoint {
   const grpc_endpoint_vtable *vtable;
 };
 
-#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/endpoint_pair.h b/src/core/lib/iomgr/endpoint_pair.h
index b60e62fc3e..f8830022f4 100644
--- a/src/core/lib/iomgr/endpoint_pair.h
+++ b/src/core/lib/iomgr/endpoint_pair.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/iomgr/endpoint.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
   grpc_endpoint *client;
   grpc_endpoint *server;
@@ -29,4 +33,8 @@ typedef struct {
 grpc_endpoint_pair grpc_iomgr_create_endpoint_pair(const char *name,
                                                    grpc_channel_args *args);
 
-#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_PAIR_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_PAIR_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/endpoint_pair_posix.c b/src/core/lib/iomgr/endpoint_pair_posix.cc
index 3ade2148ba..3ade2148ba 100644
--- a/src/core/lib/iomgr/endpoint_pair_posix.c
+++ b/src/core/lib/iomgr/endpoint_pair_posix.cc
diff --git a/src/core/lib/iomgr/endpoint_pair_uv.c b/src/core/lib/iomgr/endpoint_pair_uv.cc
index ff72fe0492..ff72fe0492 100644
--- a/src/core/lib/iomgr/endpoint_pair_uv.c
+++ b/src/core/lib/iomgr/endpoint_pair_uv.cc
diff --git a/src/core/lib/iomgr/endpoint_pair_windows.c b/src/core/lib/iomgr/endpoint_pair_windows.cc
index 782fa2fd69..782fa2fd69 100644
--- a/src/core/lib/iomgr/endpoint_pair_windows.c
+++ b/src/core/lib/iomgr/endpoint_pair_windows.cc
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.cc
index aa05501537..2ea6cf1301 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.cc
@@ -15,9 +15,11 @@
  * limitations under the License.
  *
  */
+#include <grpc/support/port_platform.h>
 
 #include "src/core/lib/iomgr/error.h"
 
+#include <inttypes.h>
 #include <string.h>
 
 #include <grpc/status.h>
diff --git a/src/core/lib/iomgr/error.h b/src/core/lib/iomgr/error.h
index b362948691..b36330a7ab 100644
--- a/src/core/lib/iomgr/error.h
+++ b/src/core/lib/iomgr/error.h
@@ -19,8 +19,8 @@
 #ifndef GRPC_CORE_LIB_IOMGR_ERROR_H
 #define GRPC_CORE_LIB_IOMGR_ERROR_H
 
+#include <inttypes.h>
 #include <stdbool.h>
-#include <stdint.h>
 
 #include <grpc/slice.h>
 #include <grpc/status.h>
diff --git a/src/core/lib/iomgr/error_internal.h b/src/core/lib/iomgr/error_internal.h
index 7507484557..f718e06d4e 100644
--- a/src/core/lib/iomgr/error_internal.h
+++ b/src/core/lib/iomgr/error_internal.h
@@ -24,6 +24,10 @@
 
 #include <grpc/support/sync.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_linked_error grpc_linked_error;
 
 struct grpc_linked_error {
@@ -57,4 +61,8 @@ struct grpc_error {
 
 bool grpc_error_is_special(grpc_error *err);
 
-#endif /* GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/ev_epoll1_linux.c b/src/core/lib/iomgr/ev_epoll1_linux.cc
index 3ac12ab56f..6126e2771c 100644
--- a/src/core/lib/iomgr/ev_epoll1_linux.c
+++ b/src/core/lib/iomgr/ev_epoll1_linux.cc
@@ -20,11 +20,11 @@
 
 /* This polling engine is only relevant on linux kernels supporting epoll() */
 #ifdef GRPC_LINUX_EPOLL
-
 #include "src/core/lib/iomgr/ev_epoll1_linux.h"
 
 #include <assert.h>
 #include <errno.h>
+#include <limits.h>
 #include <poll.h>
 #include <pthread.h>
 #include <string.h>
@@ -40,12 +40,12 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/lockfree_event.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/string.h"
 
 static grpc_wakeup_fd global_wakeup_fd;
@@ -562,25 +562,17 @@ static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   GPR_TIMER_END("pollset_shutdown", 0);
 }
 
-static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
-                                           gpr_timespec now) {
-  gpr_timespec timeout;
-  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
-    return -1;
-  }
-
-  if (gpr_time_cmp(deadline, now) <= 0) {
+static int poll_deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                           grpc_millis millis) {
+  if (millis == GRPC_MILLIS_INF_FUTURE) return -1;
+  grpc_millis delta = millis - grpc_exec_ctx_now(exec_ctx);
+  if (delta > INT_MAX) {
+    return INT_MAX;
+  } else if (delta < 0) {
     return 0;
+  } else {
+    return (int)delta;
   }
-
-  static const gpr_timespec round_up = {
-      0,                 /* tv_sec */
-      GPR_NS_PER_MS - 1, /* tv_nsec */
-      GPR_TIMESPAN       /* clock_type */
-  };
-  timeout = gpr_time_sub(deadline, now);
-  int millis = gpr_time_to_millis(gpr_time_add(timeout, round_up));
-  return millis >= 1 ? millis : 1;
 }
 
 /* Process the epoll events found by do_epoll_wait() function.
@@ -637,11 +629,11 @@ static grpc_error *process_epoll_events(grpc_exec_ctx *exec_ctx,
    (i.e the designated poller thread) will be calling this function. So there is
    no need for any synchronization when accesing fields in g_epoll_set */
 static grpc_error *do_epoll_wait(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
-                                 gpr_timespec now, gpr_timespec deadline) {
+                                 grpc_millis deadline) {
   GPR_TIMER_BEGIN("do_epoll_wait", 0);
 
   int r;
-  int timeout = poll_deadline_to_millis_timeout(deadline, now);
+  int timeout = poll_deadline_to_millis_timeout(exec_ctx, deadline);
   if (timeout != 0) {
     GRPC_SCHEDULING_START_BLOCKING_REGION;
   }
@@ -651,7 +643,7 @@ static grpc_error *do_epoll_wait(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
                    timeout);
   } while (r < 0 && errno == EINTR);
   if (timeout != 0) {
-    GRPC_SCHEDULING_END_BLOCKING_REGION;
+    GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(exec_ctx);
   }
 
   if (r < 0) return GRPC_OS_ERROR(errno, "epoll_wait");
@@ -669,9 +661,10 @@ static grpc_error *do_epoll_wait(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
   return GRPC_ERROR_NONE;
 }
 
-static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                         grpc_pollset_worker **worker_hdl, gpr_timespec *now,
-                         gpr_timespec deadline) {
+static bool begin_worker(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
+                         grpc_pollset_worker *worker,
+                         grpc_pollset_worker **worker_hdl,
+                         grpc_millis deadline) {
   GPR_TIMER_BEGIN("begin_worker", 0);
   if (worker_hdl != NULL) *worker_hdl = worker;
   worker->initialized_cv = false;
@@ -756,14 +749,15 @@ static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker,
                 pollset->shutting_down);
       }
 
-      if (gpr_cv_wait(&worker->cv, &pollset->mu, deadline) &&
+      if (gpr_cv_wait(&worker->cv, &pollset->mu,
+                      grpc_millis_to_timespec(deadline, GPR_CLOCK_REALTIME)) &&
           worker->state == UNKICKED) {
         /* If gpr_cv_wait returns true (i.e a timeout), pretend that the worker
            received a kick */
         SET_KICK_STATE(worker, KICKED);
       }
     }
-    *now = gpr_now(now->clock_type);
+    grpc_exec_ctx_invalidate_now(exec_ctx);
   }
 
   if (GRPC_TRACER_ON(grpc_polling_trace)) {
@@ -942,7 +936,7 @@ static void end_worker(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
    ensure that it is held by the time the function returns */
 static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
                                 grpc_pollset_worker **worker_hdl,
-                                gpr_timespec now, gpr_timespec deadline) {
+                                grpc_millis deadline) {
   grpc_pollset_worker worker;
   grpc_error *error = GRPC_ERROR_NONE;
   static const char *err_desc = "pollset_work";
@@ -953,7 +947,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
     return GRPC_ERROR_NONE;
   }
 
-  if (begin_worker(ps, &worker, worker_hdl, &now, deadline)) {
+  if (begin_worker(exec_ctx, ps, &worker, worker_hdl, deadline)) {
     gpr_tls_set(&g_current_thread_pollset, (intptr_t)ps);
     gpr_tls_set(&g_current_thread_worker, (intptr_t)&worker);
     GPR_ASSERT(!ps->shutting_down);
@@ -976,8 +970,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *ps,
        designated poller */
     if (gpr_atm_acq_load(&g_epoll_set.cursor) ==
         gpr_atm_acq_load(&g_epoll_set.num_events)) {
-      append_error(&error, do_epoll_wait(exec_ctx, ps, now, deadline),
-                   err_desc);
+      append_error(&error, do_epoll_wait(exec_ctx, ps, deadline), err_desc);
     }
     append_error(&error, process_epoll_events(exec_ctx, ps), err_desc);
 
@@ -1257,7 +1250,7 @@ const grpc_event_engine_vtable *grpc_init_epoll1_linux(bool explicit_request) {
 
 #else /* defined(GRPC_LINUX_EPOLL) */
 #if defined(GRPC_POSIX_SOCKET)
-#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/ev_epoll1_linux.h"
 /* If GRPC_LINUX_EPOLL is not defined, it means epoll is not available. Return
  * NULL */
 const grpc_event_engine_vtable *grpc_init_epoll1_linux(bool explicit_request) {
diff --git a/src/core/lib/iomgr/ev_epoll1_linux.h b/src/core/lib/iomgr/ev_epoll1_linux.h
index 0696e0df40..66fd826b49 100644
--- a/src/core/lib/iomgr/ev_epoll1_linux.h
+++ b/src/core/lib/iomgr/ev_epoll1_linux.h
@@ -22,8 +22,16 @@
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/port.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // a polling engine that utilizes a singleton epoll set and turnstile polling
 
 const grpc_event_engine_vtable *grpc_init_epoll1_linux(bool explicit_request);
 
-#endif /* GRPC_CORE_LIB_IOMGR_EV_EPOLL1_LINUX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_EV_EPOLL1_LINUX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/ev_epollex_linux.c b/src/core/lib/iomgr/ev_epollex_linux.cc
index 8eb4de44d9..59dd8fd2fe 100644
--- a/src/core/lib/iomgr/ev_epollex_linux.c
+++ b/src/core/lib/iomgr/ev_epollex_linux.cc
@@ -25,6 +25,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <limits.h>
 #include <poll.h>
 #include <pthread.h>
 #include <string.h>
@@ -38,7 +39,7 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/debug/stats.h"
-#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/is_epollexclusive_available.h"
 #include "src/core/lib/iomgr/lockfree_event.h"
@@ -46,19 +47,18 @@
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/spinlock.h"
 
 /*******************************************************************************
  * Polling object
  */
-
 typedef enum {
   PO_POLLING_GROUP,
   PO_POLLSET_SET,
   PO_POLLSET,
-  PO_FD, /* ordering is important: we always want to lock pollsets before fds:
-            this guarantees that using an fd as a pollable is safe */
+  PO_FD,
+  /* ordering is important: we always want to lock pollsets before fds:
+     this guarantees that using an fd as a pollable is safe */
   PO_EMPTY_POLLABLE,
   PO_COUNT
 } polling_obj_type;
@@ -690,32 +690,16 @@ static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
   *mu = &pollset->pollable_obj.po.mu;
 }
 
-/* Convert a timespec to milliseconds:
-   - Very small or negative poll times are clamped to zero to do a non-blocking
-     poll (which becomes spin polling)
-   - Other small values are rounded up to one millisecond
-   - Longer than a millisecond polls are rounded up to the next nearest
-     millisecond to avoid spinning
-   - Infinite timeouts are converted to -1 */
-static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
-                                           gpr_timespec now) {
-  gpr_timespec timeout;
-  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
-    return -1;
-  }
-
-  if (gpr_time_cmp(deadline, now) <= 0) {
+static int poll_deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                           grpc_millis millis) {
+  if (millis == GRPC_MILLIS_INF_FUTURE) return -1;
+  grpc_millis delta = millis - grpc_exec_ctx_now(exec_ctx);
+  if (delta > INT_MAX)
+    return INT_MAX;
+  else if (delta < 0)
     return 0;
-  }
-
-  static const gpr_timespec round_up = {
-      0,                 /* tv_sec */
-      GPR_NS_PER_MS - 1, /* tv_nsec */
-      GPR_TIMESPAN       /* clock_type */
-  };
-  timeout = gpr_time_sub(deadline, now);
-  int millis = gpr_time_to_millis(gpr_time_add(timeout, round_up));
-  return millis >= 1 ? millis : 1;
+  else
+    return (int)delta;
 }
 
 static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
@@ -810,9 +794,8 @@ static void pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {
 }
 
 static grpc_error *pollset_epoll(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                                 pollable *p, gpr_timespec now,
-                                 gpr_timespec deadline) {
-  int timeout = poll_deadline_to_millis_timeout(deadline, now);
+                                 pollable *p, grpc_millis deadline) {
+  int timeout = poll_deadline_to_millis_timeout(exec_ctx, deadline);
 
   if (GRPC_TRACER_ON(grpc_polling_trace)) {
     char *desc = pollable_desc(p);
@@ -829,7 +812,7 @@ static grpc_error *pollset_epoll(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
     r = epoll_wait(p->epfd, pollset->events, MAX_EPOLL_EVENTS, timeout);
   } while (r < 0 && errno == EINTR);
   if (timeout != 0) {
-    GRPC_SCHEDULING_END_BLOCKING_REGION;
+    GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(exec_ctx);
   }
 
   if (r < 0) return GRPC_OS_ERROR(errno, "epoll_wait");
@@ -884,9 +867,10 @@ static worker_remove_result worker_remove(grpc_pollset_worker **root,
 }
 
 /* Return true if this thread should poll */
-static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                         grpc_pollset_worker **worker_hdl, gpr_timespec *now,
-                         gpr_timespec deadline) {
+static bool begin_worker(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
+                         grpc_pollset_worker *worker,
+                         grpc_pollset_worker **worker_hdl,
+                         grpc_millis deadline) {
   bool do_poll = true;
   if (worker_hdl != NULL) *worker_hdl = worker;
   worker->initialized_cv = false;
@@ -910,10 +894,11 @@ static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker,
         worker->pollable_obj->root_worker != worker) {
       gpr_log(GPR_DEBUG, "PS:%p wait %p w=%p for %dms", pollset,
               worker->pollable_obj, worker,
-              poll_deadline_to_millis_timeout(deadline, *now));
+              poll_deadline_to_millis_timeout(exec_ctx, deadline));
     }
     while (do_poll && worker->pollable_obj->root_worker != worker) {
-      if (gpr_cv_wait(&worker->cv, &worker->pollable_obj->po.mu, deadline)) {
+      if (gpr_cv_wait(&worker->cv, &worker->pollable_obj->po.mu,
+                      grpc_millis_to_timespec(deadline, GPR_CLOCK_REALTIME))) {
         if (GRPC_TRACER_ON(grpc_polling_trace)) {
           gpr_log(GPR_DEBUG, "PS:%p timeout_wait %p w=%p", pollset,
                   worker->pollable_obj, worker);
@@ -936,7 +921,7 @@ static bool begin_worker(grpc_pollset *pollset, grpc_pollset_worker *worker,
       gpr_mu_lock(&pollset->pollable_obj.po.mu);
       gpr_mu_lock(&worker->pollable_obj->po.mu);
     }
-    *now = gpr_now(now->clock_type);
+    grpc_exec_ctx_invalidate_now(exec_ctx);
   }
 
   return do_poll && pollset->shutdown_closure == NULL &&
@@ -967,14 +952,13 @@ static void end_worker(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
    ensure that it is held by the time the function returns */
 static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                                 grpc_pollset_worker **worker_hdl,
-                                gpr_timespec now, gpr_timespec deadline) {
+                                grpc_millis deadline) {
   grpc_pollset_worker worker;
   if (0 && GRPC_TRACER_ON(grpc_polling_trace)) {
-    gpr_log(GPR_DEBUG, "PS:%p work hdl=%p worker=%p now=%" PRId64
-                       ".%09d deadline=%" PRId64 ".%09d kwp=%d root_worker=%p",
-            pollset, worker_hdl, &worker, now.tv_sec, now.tv_nsec,
-            deadline.tv_sec, deadline.tv_nsec, pollset->kicked_without_poller,
-            pollset->root_worker);
+    gpr_log(GPR_DEBUG, "PS:%p work hdl=%p worker=%p now=%" PRIdPTR
+                       " deadline=%" PRIdPTR " kwp=%d root_worker=%p",
+            pollset, worker_hdl, &worker, grpc_exec_ctx_now(exec_ctx), deadline,
+            pollset->kicked_without_poller, pollset->root_worker);
   }
   grpc_error *error = GRPC_ERROR_NONE;
   static const char *err_desc = "pollset_work";
@@ -985,7 +969,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   if (pollset->current_pollable_obj != &pollset->pollable_obj) {
     gpr_mu_lock(&pollset->current_pollable_obj->po.mu);
   }
-  if (begin_worker(pollset, &worker, worker_hdl, &now, deadline)) {
+  if (begin_worker(exec_ctx, pollset, &worker, worker_hdl, deadline)) {
     gpr_tls_set(&g_current_thread_pollset, (intptr_t)pollset);
     gpr_tls_set(&g_current_thread_worker, (intptr_t)&worker);
     GPR_ASSERT(!pollset->shutdown_closure);
@@ -996,7 +980,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
     gpr_mu_unlock(&pollset->pollable_obj.po.mu);
     if (pollset->event_cursor == pollset->event_count) {
       append_error(&error, pollset_epoll(exec_ctx, pollset, worker.pollable_obj,
-                                         now, deadline),
+                                         deadline),
                    err_desc);
     }
     append_error(&error, pollset_process_events(exec_ctx, pollset, false),
@@ -1449,7 +1433,7 @@ const grpc_event_engine_vtable *grpc_init_epollex_linux(
 
 #else /* defined(GRPC_LINUX_EPOLL) */
 #if defined(GRPC_POSIX_SOCKET)
-#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/ev_epollex_linux.h"
 /* If GRPC_LINUX_EPOLL is not defined, it means epoll is not available. Return
  * NULL */
 const grpc_event_engine_vtable *grpc_init_epollex_linux(
diff --git a/src/core/lib/iomgr/ev_epollex_linux.h b/src/core/lib/iomgr/ev_epollex_linux.h
index cff9b43c02..58cc5a24f8 100644
--- a/src/core/lib/iomgr/ev_epollex_linux.h
+++ b/src/core/lib/iomgr/ev_epollex_linux.h
@@ -22,7 +22,15 @@
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/port.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 const grpc_event_engine_vtable *grpc_init_epollex_linux(
     bool explicitly_requested);
 
-#endif /* GRPC_CORE_LIB_IOMGR_EV_EPOLLEX_LINUX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_EV_EPOLLEX_LINUX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/ev_epollsig_linux.c b/src/core/lib/iomgr/ev_epollsig_linux.cc
index 4d8bdf1401..370ea1d50b 100644
--- a/src/core/lib/iomgr/ev_epollsig_linux.c
+++ b/src/core/lib/iomgr/ev_epollsig_linux.cc
@@ -25,6 +25,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <limits.h>
 #include <poll.h>
 #include <pthread.h>
 #include <signal.h>
@@ -40,13 +41,13 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/lockfree_event.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/support/block_annotate.h"
 
 #define GRPC_POLLSET_KICK_BROADCAST ((grpc_pollset_worker *)1)
 
@@ -1089,30 +1090,16 @@ static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
   pollset->shutdown_done = NULL;
 }
 
-/* Convert a timespec to milliseconds:
-   - Very small or negative poll times are clamped to zero to do a non-blocking
-     poll (which becomes spin polling)
-   - Other small values are rounded up to one millisecond
-   - Longer than a millisecond polls are rounded up to the next nearest
-     millisecond to avoid spinning
-   - Infinite timeouts are converted to -1 */
-static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
-                                           gpr_timespec now) {
-  gpr_timespec timeout;
-  static const int64_t max_spin_polling_us = 10;
-  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
-    return -1;
-  }
-
-  if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
-                                                   max_spin_polling_us,
-                                                   GPR_TIMESPAN))) <= 0) {
+static int poll_deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                           grpc_millis millis) {
+  if (millis == GRPC_MILLIS_INF_FUTURE) return -1;
+  grpc_millis delta = millis - grpc_exec_ctx_now(exec_ctx);
+  if (delta > INT_MAX)
+    return INT_MAX;
+  else if (delta < 0)
     return 0;
-  }
-  timeout = gpr_time_sub(deadline, now);
-  int millis = gpr_time_to_millis(gpr_time_add(
-      timeout, gpr_time_from_nanos(GPR_NS_PER_MS - 1, GPR_TIMESPAN)));
-  return millis >= 1 ? millis : 1;
+  else
+    return (int)delta;
 }
 
 static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
@@ -1243,7 +1230,7 @@ static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
   GRPC_STATS_INC_SYSCALL_POLL(exec_ctx);
   ep_rv =
       epoll_pwait(epoll_fd, ep_ev, GRPC_EPOLL_MAX_EVENTS, timeout_ms, sig_mask);
-  GRPC_SCHEDULING_END_BLOCKING_REGION;
+  GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(exec_ctx);
   if (ep_rv < 0) {
     if (errno != EINTR) {
       gpr_asprintf(&err_msg,
@@ -1310,10 +1297,10 @@ static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
    ensure that it is held by the time the function returns */
 static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                                 grpc_pollset_worker **worker_hdl,
-                                gpr_timespec now, gpr_timespec deadline) {
+                                grpc_millis deadline) {
   GPR_TIMER_BEGIN("pollset_work", 0);
   grpc_error *error = GRPC_ERROR_NONE;
-  int timeout_ms = poll_deadline_to_millis_timeout(deadline, now);
+  int timeout_ms = poll_deadline_to_millis_timeout(exec_ctx, deadline);
 
   sigset_t new_mask;
 
@@ -1756,7 +1743,7 @@ const grpc_event_engine_vtable *grpc_init_epollsig_linux(
 
 #else /* defined(GRPC_LINUX_EPOLL) */
 #if defined(GRPC_POSIX_SOCKET)
-#include "src/core/lib/iomgr/ev_posix.h"
+#include "src/core/lib/iomgr/ev_epollsig_linux.h"
 /* If GRPC_LINUX_EPOLL is not defined, it means epoll is not available. Return
  * NULL */
 const grpc_event_engine_vtable *grpc_init_epollsig_linux(
diff --git a/src/core/lib/iomgr/ev_epollsig_linux.h b/src/core/lib/iomgr/ev_epollsig_linux.h
index 88328682b3..c04ff27400 100644
--- a/src/core/lib/iomgr/ev_epollsig_linux.h
+++ b/src/core/lib/iomgr/ev_epollsig_linux.h
@@ -22,6 +22,10 @@
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/port.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 const grpc_event_engine_vtable *grpc_init_epollsig_linux(bool explicit_request);
 
 #ifdef GRPC_LINUX_EPOLL
@@ -30,4 +34,8 @@ void *grpc_pollset_get_polling_island(grpc_pollset *ps);
 bool grpc_are_polling_islands_equal(void *p, void *q);
 #endif /* defined(GRPC_LINUX_EPOLL) */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_EV_EPOLLSIG_LINUX_H */
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.cc
index e170702dca..036a35690c 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.cc
@@ -24,6 +24,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <limits.h>
 #include <poll.h>
 #include <string.h>
 #include <sys/socket.h>
@@ -37,12 +38,11 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/lib/debug/stats.h"
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
-#include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/iomgr/wakeup_fd_cv.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 #include "src/core/lib/profiling/timers.h"
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/murmur_hash.h"
 
 #define GRPC_POLLSET_KICK_BROADCAST ((grpc_pollset_worker *)1)
@@ -50,7 +50,6 @@
 /*******************************************************************************
  * FD declarations
  */
-
 typedef struct grpc_fd_watcher {
   struct grpc_fd_watcher *next;
   struct grpc_fd_watcher *prev;
@@ -200,8 +199,8 @@ static void pollset_set_add_fd(grpc_exec_ctx *exec_ctx,
    - longer than a millisecond polls are rounded up to the next nearest
      millisecond to avoid spinning
    - infinite timeouts are converted to -1 */
-static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
-                                           gpr_timespec now);
+static int poll_deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                           grpc_millis deadline);
 
 /* Allow kick to wakeup the currently polling worker */
 #define GRPC_POLLSET_CAN_KICK_SELF 1
@@ -876,7 +875,7 @@ static void work_combine_error(grpc_error **composite, grpc_error *error) {
 
 static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                                 grpc_pollset_worker **worker_hdl,
-                                gpr_timespec now, gpr_timespec deadline) {
+                                grpc_millis deadline) {
   grpc_pollset_worker worker;
   if (worker_hdl) *worker_hdl = &worker;
   grpc_error *error = GRPC_ERROR_NONE;
@@ -945,7 +944,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
       grpc_fd_watcher *watchers;
       struct pollfd *pfds;
 
-      timeout = poll_deadline_to_millis_timeout(deadline, now);
+      timeout = poll_deadline_to_millis_timeout(exec_ctx, deadline);
 
       if (pollset->fd_count + 2 <= inline_elements) {
         pfds = pollfd_space;
@@ -991,7 +990,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
       GRPC_SCHEDULING_START_BLOCKING_REGION;
       GRPC_STATS_INC_SYSCALL_POLL(exec_ctx);
       r = grpc_poll_function(pfds, pfd_count, timeout);
-      GRPC_SCHEDULING_END_BLOCKING_REGION;
+      GRPC_SCHEDULING_END_BLOCKING_REGION_WITH_EXEC_CTX(exec_ctx);
 
       if (GRPC_TRACER_ON(grpc_polling_trace)) {
         gpr_log(GPR_DEBUG, "%p poll=%d", pollset, r);
@@ -1068,13 +1067,10 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
       if (queued_work || worker.kicked_specifically) {
         /* If there's queued work on the list, then set the deadline to be
            immediate so we get back out of the polling loop quickly */
-        deadline = gpr_inf_past(GPR_CLOCK_MONOTONIC);
+        deadline = 0;
       }
       keep_polling = 1;
     }
-    if (keep_polling) {
-      now = gpr_now(now.clock_type);
-    }
   }
   gpr_tls_set(&g_current_thread_poller, 0);
   if (added_worker) {
@@ -1126,21 +1122,14 @@ static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   }
 }
 
-static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
-                                           gpr_timespec now) {
-  gpr_timespec timeout;
-  static const int64_t max_spin_polling_us = 10;
-  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
-    return -1;
-  }
-  if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
-                                                   max_spin_polling_us,
-                                                   GPR_TIMESPAN))) <= 0) {
-    return 0;
-  }
-  timeout = gpr_time_sub(deadline, now);
-  return gpr_time_to_millis(gpr_time_add(
-      timeout, gpr_time_from_nanos(GPR_NS_PER_MS - 1, GPR_TIMESPAN)));
+static int poll_deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                           grpc_millis deadline) {
+  if (deadline == GRPC_MILLIS_INF_FUTURE) return -1;
+  if (deadline == 0) return 0;
+  grpc_millis n = deadline - grpc_exec_ctx_now(exec_ctx);
+  if (n < 0) return 0;
+  if (n > INT_MAX) return -1;
+  return (int)n;
 }
 
 /*******************************************************************************
diff --git a/src/core/lib/iomgr/ev_poll_posix.h b/src/core/lib/iomgr/ev_poll_posix.h
index d444e60944..84b68155b5 100644
--- a/src/core/lib/iomgr/ev_poll_posix.h
+++ b/src/core/lib/iomgr/ev_poll_posix.h
@@ -21,7 +21,15 @@
 
 #include "src/core/lib/iomgr/ev_posix.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 const grpc_event_engine_vtable *grpc_init_poll_posix(bool explicit_request);
 const grpc_event_engine_vtable *grpc_init_poll_cv_posix(bool explicit_request);
 
-#endif /* GRPC_CORE_LIB_IOMGR_EV_POLL_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_EV_POLL_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/ev_posix.c b/src/core/lib/iomgr/ev_posix.cc
index 4d3ae2228e..e4033fab1d 100644
--- a/src/core/lib/iomgr/ev_posix.c
+++ b/src/core/lib/iomgr/ev_posix.cc
@@ -205,9 +205,9 @@ void grpc_pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {
 }
 
 grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                              grpc_pollset_worker **worker, gpr_timespec now,
-                              gpr_timespec deadline) {
-  return g_event_engine->pollset_work(exec_ctx, pollset, worker, now, deadline);
+                              grpc_pollset_worker **worker,
+                              grpc_millis deadline) {
+  return g_event_engine->pollset_work(exec_ctx, pollset, worker, deadline);
 }
 
 grpc_error *grpc_pollset_kick(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
diff --git a/src/core/lib/iomgr/ev_posix.h b/src/core/lib/iomgr/ev_posix.h
index 1ff2ff1413..955326c5f7 100644
--- a/src/core/lib/iomgr/ev_posix.h
+++ b/src/core/lib/iomgr/ev_posix.h
@@ -27,6 +27,10 @@
 #include "src/core/lib/iomgr/pollset_set.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_tracer_flag grpc_polling_trace; /* Disabled by default */
 
 typedef struct grpc_fd grpc_fd;
@@ -52,8 +56,8 @@ typedef struct grpc_event_engine_vtable {
                            grpc_closure *closure);
   void (*pollset_destroy)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset);
   grpc_error *(*pollset_work)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                              grpc_pollset_worker **worker, gpr_timespec now,
-                              gpr_timespec deadline);
+                              grpc_pollset_worker **worker,
+                              grpc_millis deadline);
   grpc_error *(*pollset_kick)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                               grpc_pollset_worker *specific_worker);
   void (*pollset_add_fd)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
@@ -158,4 +162,8 @@ extern grpc_poll_function_type grpc_poll_function;
 void grpc_set_event_engine_test_only(const grpc_event_engine_vtable *);
 const grpc_event_engine_vtable *grpc_get_event_engine_test_only();
 
-#endif /* GRPC_CORE_LIB_IOMGR_EV_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_EV_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/ev_windows.c b/src/core/lib/iomgr/ev_windows.cc
index c24dfaeaf7..c24dfaeaf7 100644
--- a/src/core/lib/iomgr/ev_windows.c
+++ b/src/core/lib/iomgr/ev_windows.cc
diff --git a/src/core/lib/iomgr/exec_ctx.c b/src/core/lib/iomgr/exec_ctx.cc
index 41c69add17..3d17afcb8f 100644
--- a/src/core/lib/iomgr/exec_ctx.c
+++ b/src/core/lib/iomgr/exec_ctx.cc
@@ -104,9 +104,69 @@ static void exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
   grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
 }
 
-void grpc_exec_ctx_global_init(void) {}
+static gpr_timespec
+    g_start_time[GPR_TIMESPAN + 1];  // assumes GPR_TIMESPAN is the
+                                     // last enum value in
+                                     // gpr_clock_type
+
+void grpc_exec_ctx_global_init(void) {
+  for (int i = 0; i < GPR_TIMESPAN; i++) {
+    g_start_time[i] = gpr_now((gpr_clock_type)i);
+  }
+  // allows uniform treatment in conversion functions
+  g_start_time[GPR_TIMESPAN] = gpr_time_0(GPR_TIMESPAN);
+}
+
 void grpc_exec_ctx_global_shutdown(void) {}
 
+static gpr_atm timespec_to_atm_round_down(gpr_timespec ts) {
+  ts = gpr_time_sub(ts, g_start_time[ts.clock_type]);
+  double x =
+      GPR_MS_PER_SEC * (double)ts.tv_sec + (double)ts.tv_nsec / GPR_NS_PER_MS;
+  if (x < 0) return 0;
+  if (x > GPR_ATM_MAX) return GPR_ATM_MAX;
+  return (gpr_atm)x;
+}
+
+static gpr_atm timespec_to_atm_round_up(gpr_timespec ts) {
+  ts = gpr_time_sub(ts, g_start_time[ts.clock_type]);
+  double x = GPR_MS_PER_SEC * (double)ts.tv_sec +
+             (double)ts.tv_nsec / GPR_NS_PER_MS +
+             (double)(GPR_NS_PER_SEC - 1) / (double)GPR_NS_PER_SEC;
+  if (x < 0) return 0;
+  if (x > GPR_ATM_MAX) return GPR_ATM_MAX;
+  return (gpr_atm)x;
+}
+
+grpc_millis grpc_exec_ctx_now(grpc_exec_ctx *exec_ctx) {
+  if (!exec_ctx->now_is_valid) {
+    exec_ctx->now = timespec_to_atm_round_down(gpr_now(GPR_CLOCK_MONOTONIC));
+    exec_ctx->now_is_valid = true;
+  }
+  return exec_ctx->now;
+}
+
+void grpc_exec_ctx_invalidate_now(grpc_exec_ctx *exec_ctx) {
+  exec_ctx->now_is_valid = false;
+}
+
+gpr_timespec grpc_millis_to_timespec(grpc_millis millis,
+                                     gpr_clock_type clock_type) {
+  if (clock_type == GPR_TIMESPAN) {
+    return gpr_time_from_millis(millis, GPR_TIMESPAN);
+  }
+  return gpr_time_add(g_start_time[clock_type],
+                      gpr_time_from_millis(millis, GPR_TIMESPAN));
+}
+
+grpc_millis grpc_timespec_to_millis_round_down(gpr_timespec ts) {
+  return timespec_to_atm_round_down(ts);
+}
+
+grpc_millis grpc_timespec_to_millis_round_up(gpr_timespec ts) {
+  return timespec_to_atm_round_up(ts);
+}
+
 static const grpc_closure_scheduler_vtable exec_ctx_scheduler_vtable = {
     exec_ctx_run, exec_ctx_sched, "exec_ctx"};
 static grpc_closure_scheduler exec_ctx_scheduler = {&exec_ctx_scheduler_vtable};
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index c89792c8c4..44b9be7aa9 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -19,10 +19,19 @@
 #ifndef GRPC_CORE_LIB_IOMGR_EXEC_CTX_H
 #define GRPC_CORE_LIB_IOMGR_EXEC_CTX_H
 
+#include <grpc/support/atm.h>
 #include <grpc/support/cpu.h>
+
 #include "src/core/lib/iomgr/closure.h"
 
-/* #define GRPC_EXECUTION_CONTEXT_SANITIZER 1 */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef gpr_atm grpc_millis;
+
+#define GRPC_MILLIS_INF_FUTURE GPR_ATM_MAX
+#define GRPC_MILLIS_INF_PAST GPR_ATM_MIN
 
 /** A workqueue represents a list of work to be executed asynchronously.
     Forward declared here to avoid a circular dependency with workqueue.h. */
@@ -66,6 +75,9 @@ struct grpc_exec_ctx {
   unsigned starting_cpu;
   void *check_ready_to_finish_arg;
   bool (*check_ready_to_finish)(grpc_exec_ctx *exec_ctx, void *arg);
+
+  bool now_is_valid;
+  grpc_millis now;
 };
 
 /* initializer for grpc_exec_ctx:
@@ -73,7 +85,7 @@ struct grpc_exec_ctx {
 #define GRPC_EXEC_CTX_INITIALIZER(flags, finish_check, finish_check_arg) \
   {                                                                      \
     GRPC_CLOSURE_LIST_INIT, NULL, NULL, flags, gpr_cpu_current_cpu(),    \
-        finish_check_arg, finish_check                                   \
+        finish_check_arg, finish_check, false, 0                         \
   }
 
 /* initialize an execution context at the top level of an API call into grpc
@@ -106,4 +118,14 @@ void grpc_exec_ctx_global_init(void);
 void grpc_exec_ctx_global_init(void);
 void grpc_exec_ctx_global_shutdown(void);
 
+grpc_millis grpc_exec_ctx_now(grpc_exec_ctx *exec_ctx);
+void grpc_exec_ctx_invalidate_now(grpc_exec_ctx *exec_ctx);
+gpr_timespec grpc_millis_to_timespec(grpc_millis millis, gpr_clock_type clock);
+grpc_millis grpc_timespec_to_millis_round_down(gpr_timespec timespec);
+grpc_millis grpc_timespec_to_millis_round_up(gpr_timespec timespec);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_EXEC_CTX_H */
diff --git a/src/core/lib/iomgr/executor.c b/src/core/lib/iomgr/executor.cc
index 2439f15a8a..92c3e70301 100644
--- a/src/core/lib/iomgr/executor.c
+++ b/src/core/lib/iomgr/executor.cc
@@ -32,14 +32,16 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/support/spinlock.h"
 
+#define MAX_DEPTH 2
+
 typedef struct {
   gpr_mu mu;
   gpr_cv cv;
   grpc_closure_list elems;
+  size_t depth;
   bool shutdown;
   bool queued_long_job;
   gpr_thd_id id;
-  grpc_closure_list local_elems;
 } thread_state;
 
 static thread_state *g_thread_state;
@@ -54,35 +56,32 @@ static grpc_tracer_flag executor_trace =
 
 static void executor_thread(void *arg);
 
-static void run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list *list) {
-  int n = 0;  // number of closures executed
+static size_t run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list list) {
+  size_t n = 0;
 
-  while (!grpc_closure_list_empty(*list)) {
-    grpc_closure *c = list->head;
-    grpc_closure_list_init(list);
-    while (c != NULL) {
-      grpc_closure *next = c->next_data.next;
-      grpc_error *error = c->error_data.error;
-      if (GRPC_TRACER_ON(executor_trace)) {
+  grpc_closure *c = list.head;
+  while (c != NULL) {
+    grpc_closure *next = c->next_data.next;
+    grpc_error *error = c->error_data.error;
+    if (GRPC_TRACER_ON(executor_trace)) {
 #ifndef NDEBUG
-        gpr_log(GPR_DEBUG, "EXECUTOR: run %p [created by %s:%d]", c,
-                c->file_created, c->line_created);
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p [created by %s:%d]", c,
+              c->file_created, c->line_created);
 #else
-        gpr_log(GPR_DEBUG, "EXECUTOR: run %p", c);
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p", c);
 #endif
-      }
+    }
 #ifndef NDEBUG
-      c->scheduled = false;
+    c->scheduled = false;
 #endif
-      n++;
-      c->cb(exec_ctx, c->cb_arg, error);
-      GRPC_ERROR_UNREF(error);
-      c = next;
-      grpc_exec_ctx_flush(exec_ctx);
-    }
+    c->cb(exec_ctx, c->cb_arg, error);
+    GRPC_ERROR_UNREF(error);
+    c = next;
+    n++;
+    grpc_exec_ctx_flush(exec_ctx);
   }
 
-  GRPC_STATS_INC_EXECUTOR_CLOSURES_PER_WAKEUP(exec_ctx, n);
+  return n;
 }
 
 bool grpc_executor_is_threaded() {
@@ -101,7 +100,7 @@ void grpc_executor_set_threading(grpc_exec_ctx *exec_ctx, bool threading) {
     for (size_t i = 0; i < g_max_threads; i++) {
       gpr_mu_init(&g_thread_state[i].mu);
       gpr_cv_init(&g_thread_state[i].cv);
-      g_thread_state[i].elems = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT;
+      g_thread_state[i].elems = GRPC_CLOSURE_LIST_INIT;
     }
 
     gpr_thd_options opt = gpr_thd_options_default();
@@ -127,7 +126,7 @@ void grpc_executor_set_threading(grpc_exec_ctx *exec_ctx, bool threading) {
     for (size_t i = 0; i < g_max_threads; i++) {
       gpr_mu_destroy(&g_thread_state[i].mu);
       gpr_cv_destroy(&g_thread_state[i].cv);
-      run_closures(exec_ctx, &g_thread_state[i].elems);
+      run_closures(exec_ctx, g_thread_state[i].elems);
     }
     gpr_free(g_thread_state);
     gpr_tls_destroy(&g_this_thread_state);
@@ -151,14 +150,14 @@ static void executor_thread(void *arg) {
   grpc_exec_ctx exec_ctx =
       GRPC_EXEC_CTX_INITIALIZER(0, grpc_never_ready_to_finish, NULL);
 
-  GRPC_STATS_INC_EXECUTOR_THREADS_CREATED(&exec_ctx);
-
-  bool used = false;
+  size_t subtract_depth = 0;
   for (;;) {
     if (GRPC_TRACER_ON(executor_trace)) {
-      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: step", (int)(ts - g_thread_state));
+      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: step (sub_depth=%" PRIdPTR ")",
+              (int)(ts - g_thread_state), subtract_depth);
     }
     gpr_mu_lock(&ts->mu);
+    ts->depth -= subtract_depth;
     while (grpc_closure_list_empty(ts->elems) && !ts->shutdown) {
       ts->queued_long_job = false;
       gpr_cv_wait(&ts->cv, &ts->mu, gpr_inf_future(GPR_CLOCK_REALTIME));
@@ -171,20 +170,16 @@ static void executor_thread(void *arg) {
       gpr_mu_unlock(&ts->mu);
       break;
     }
-    if (!used) {
-      GRPC_STATS_INC_EXECUTOR_THREADS_USED(&exec_ctx);
-      used = true;
-    }
     GRPC_STATS_INC_EXECUTOR_QUEUE_DRAINED(&exec_ctx);
-    GPR_ASSERT(grpc_closure_list_empty(ts->local_elems));
-    ts->local_elems = ts->elems;
-    ts->elems = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT;
+    grpc_closure_list exec = ts->elems;
+    ts->elems = GRPC_CLOSURE_LIST_INIT;
     gpr_mu_unlock(&ts->mu);
     if (GRPC_TRACER_ON(executor_trace)) {
       gpr_log(GPR_DEBUG, "EXECUTOR[%d]: execute", (int)(ts - g_thread_state));
     }
 
-    run_closures(&exec_ctx, &ts->local_elems);
+    grpc_exec_ctx_invalidate_now(&exec_ctx);
+    subtract_depth = run_closures(&exec_ctx, exec);
   }
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -217,10 +212,6 @@ static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
       ts = &g_thread_state[GPR_HASH_POINTER(exec_ctx, cur_thread_count)];
     } else {
       GRPC_STATS_INC_EXECUTOR_SCHEDULED_TO_SELF(exec_ctx);
-      if (is_short) {
-        grpc_closure_list_append(&ts->local_elems, closure, error);
-        return;
-      }
     }
     thread_state *orig_ts = ts;
 
@@ -260,7 +251,8 @@ static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
         gpr_cv_signal(&ts->cv);
       }
       grpc_closure_list_append(&ts->elems, closure, error);
-      try_new_thread = ts->elems.head != closure &&
+      ts->depth++;
+      try_new_thread = ts->depth > MAX_DEPTH &&
                        cur_thread_count < g_max_threads && !ts->shutdown;
       if (!is_short) ts->queued_long_job = true;
       gpr_mu_unlock(&ts->mu);
diff --git a/src/core/lib/iomgr/executor.h b/src/core/lib/iomgr/executor.h
index 0412c02790..ab3fc901de 100644
--- a/src/core/lib/iomgr/executor.h
+++ b/src/core/lib/iomgr/executor.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/iomgr/closure.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   GRPC_EXECUTOR_SHORT,
   GRPC_EXECUTOR_LONG
@@ -45,4 +49,8 @@ bool grpc_executor_is_threaded();
    grpc_executor_shutdown */
 void grpc_executor_set_threading(grpc_exec_ctx *exec_ctx, bool enable);
 
-#endif /* GRPC_CORE_LIB_IOMGR_EXECUTOR_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_EXECUTOR_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/gethostname.h b/src/core/lib/iomgr/gethostname.h
index 9c6b9d8d42..f335fea586 100644
--- a/src/core/lib/iomgr/gethostname.h
+++ b/src/core/lib/iomgr/gethostname.h
@@ -19,8 +19,16 @@
 #ifndef GRPC_CORE_LIB_IOMGR_GETHOSTNAME_H
 #define GRPC_CORE_LIB_IOMGR_GETHOSTNAME_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Returns the hostname of the local machine.
 // Caller takes ownership of result.
 char *grpc_gethostname();
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_GETHOSTNAME_H */
diff --git a/src/core/lib/iomgr/gethostname_fallback.c b/src/core/lib/iomgr/gethostname_fallback.cc
index 6229461568..e6f4c2f760 100644
--- a/src/core/lib/iomgr/gethostname_fallback.c
+++ b/src/core/lib/iomgr/gethostname_fallback.cc
@@ -16,6 +16,7 @@
  *
  */
 
+#include "src/core/lib/iomgr/gethostname.h"
 #include "src/core/lib/iomgr/port.h"
 
 #ifdef GRPC_GETHOSTNAME_FALLBACK
diff --git a/src/core/lib/iomgr/gethostname_host_name_max.c b/src/core/lib/iomgr/gethostname_host_name_max.cc
index 4d0511412e..cdaf097c3e 100644
--- a/src/core/lib/iomgr/gethostname_host_name_max.c
+++ b/src/core/lib/iomgr/gethostname_host_name_max.cc
@@ -16,6 +16,7 @@
  *
  */
 
+#include "src/core/lib/iomgr/gethostname.h"
 #include "src/core/lib/iomgr/port.h"
 
 #ifdef GRPC_POSIX_HOST_NAME_MAX
diff --git a/src/core/lib/iomgr/gethostname_sysconf.c b/src/core/lib/iomgr/gethostname_sysconf.cc
index 51bac5d69d..8441e0615e 100644
--- a/src/core/lib/iomgr/gethostname_sysconf.c
+++ b/src/core/lib/iomgr/gethostname_sysconf.cc
@@ -16,6 +16,7 @@
  *
  */
 
+#include "src/core/lib/iomgr/gethostname.h"
 #include "src/core/lib/iomgr/port.h"
 
 #ifdef GRPC_POSIX_SYSCONF
diff --git a/src/core/lib/iomgr/iocp_windows.c b/src/core/lib/iomgr/iocp_windows.cc
index c082179c0b..336cc86c75 100644
--- a/src/core/lib/iomgr/iocp_windows.c
+++ b/src/core/lib/iomgr/iocp_windows.cc
@@ -26,6 +26,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/log_windows.h>
 #include <grpc/support/thd.h>
+#include <grpc/support/useful.h>
 
 #include "src/core/lib/debug/stats.h"
 #include "src/core/lib/iomgr/iocp_windows.h"
@@ -40,25 +41,17 @@ static gpr_atm g_custom_events = 0;
 
 static HANDLE g_iocp;
 
-static DWORD deadline_to_millis_timeout(gpr_timespec deadline,
-                                        gpr_timespec now) {
+static DWORD deadline_to_millis_timeout(grpc_exec_ctx *exec_ctx,
+                                        grpc_millis deadline) {
   gpr_timespec timeout;
-  static const int64_t max_spin_polling_us = 10;
-  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
+  if (deadline == GRPC_MILLIS_INF_FUTURE) {
     return INFINITE;
   }
-  if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
-                                                   max_spin_polling_us,
-                                                   GPR_TIMESPAN))) <= 0) {
-    return 0;
-  }
-  timeout = gpr_time_sub(deadline, now);
-  return (DWORD)gpr_time_to_millis(gpr_time_add(
-      timeout, gpr_time_from_nanos(GPR_NS_PER_MS - 1, GPR_TIMESPAN)));
+  return (DWORD)GPR_MAX(0, deadline - grpc_exec_ctx_now(exec_ctx));
 }
 
 grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
-                                     gpr_timespec deadline) {
+                                     grpc_millis deadline) {
   BOOL success;
   DWORD bytes = 0;
   DWORD flags = 0;
@@ -67,9 +60,9 @@ grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
   grpc_winsocket *socket;
   grpc_winsocket_callback_info *info;
   GRPC_STATS_INC_SYSCALL_POLL(exec_ctx);
-  success = GetQueuedCompletionStatus(
-      g_iocp, &bytes, &completion_key, &overlapped,
-      deadline_to_millis_timeout(deadline, gpr_now(deadline.clock_type)));
+  success =
+      GetQueuedCompletionStatus(g_iocp, &bytes, &completion_key, &overlapped,
+                                deadline_to_millis_timeout(exec_ctx, deadline));
   if (success == 0 && overlapped == NULL) {
     return GRPC_IOCP_WORK_TIMEOUT;
   }
@@ -121,7 +114,7 @@ void grpc_iocp_flush(void) {
   grpc_iocp_work_status work_status;
 
   do {
-    work_status = grpc_iocp_work(&exec_ctx, gpr_inf_past(GPR_CLOCK_MONOTONIC));
+    work_status = grpc_iocp_work(&exec_ctx, GRPC_MILLIS_INF_PAST);
   } while (work_status == GRPC_IOCP_WORK_KICK ||
            grpc_exec_ctx_flush(&exec_ctx));
 }
@@ -129,7 +122,7 @@ void grpc_iocp_flush(void) {
 void grpc_iocp_shutdown(void) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   while (gpr_atm_acq_load(&g_custom_events)) {
-    grpc_iocp_work(&exec_ctx, gpr_inf_future(GPR_CLOCK_MONOTONIC));
+    grpc_iocp_work(&exec_ctx, GRPC_MILLIS_INF_FUTURE);
     grpc_exec_ctx_flush(&exec_ctx);
   }
   grpc_exec_ctx_finish(&exec_ctx);
diff --git a/src/core/lib/iomgr/iocp_windows.h b/src/core/lib/iomgr/iocp_windows.h
index 9c89e868c5..aefe7a294a 100644
--- a/src/core/lib/iomgr/iocp_windows.h
+++ b/src/core/lib/iomgr/iocp_windows.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/iomgr/socket_windows.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   GRPC_IOCP_WORK_WORK,
   GRPC_IOCP_WORK_TIMEOUT,
@@ -30,11 +34,15 @@ typedef enum {
 } grpc_iocp_work_status;
 
 grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
-                                     gpr_timespec deadline);
+                                     grpc_millis deadline);
 void grpc_iocp_init(void);
 void grpc_iocp_kick(void);
 void grpc_iocp_flush(void);
 void grpc_iocp_shutdown(void);
 void grpc_iocp_add_socket(grpc_winsocket *);
 
-#endif /* GRPC_CORE_LIB_IOMGR_IOCP_WINDOWS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_IOCP_WINDOWS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/iomgr.c b/src/core/lib/iomgr/iomgr.cc
index f63f190155..d6a5b4a76c 100644
--- a/src/core/lib/iomgr/iomgr.c
+++ b/src/core/lib/iomgr/iomgr.cc
@@ -16,8 +16,11 @@
  *
  */
 
+#include <grpc/support/port_platform.h>
+
 #include "src/core/lib/iomgr/iomgr.h"
 
+#include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -48,7 +51,7 @@ void grpc_iomgr_init(grpc_exec_ctx *exec_ctx) {
   gpr_cv_init(&g_rcv);
   grpc_exec_ctx_global_init();
   grpc_executor_init(exec_ctx);
-  grpc_timer_list_init(gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_timer_list_init(exec_ctx);
   g_root_object.next = g_root_object.prev = &g_root_object;
   g_root_object.name = (char *)"root";
   grpc_network_status_init();
@@ -95,8 +98,9 @@ void grpc_iomgr_shutdown(grpc_exec_ctx *exec_ctx) {
       }
       last_warning_time = gpr_now(GPR_CLOCK_REALTIME);
     }
-    if (grpc_timer_check(exec_ctx, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL) ==
-        GRPC_TIMERS_FIRED) {
+    exec_ctx->now_is_valid = true;
+    exec_ctx->now = GRPC_MILLIS_INF_FUTURE;
+    if (grpc_timer_check(exec_ctx, NULL) == GRPC_TIMERS_FIRED) {
       gpr_mu_unlock(&g_mu);
       grpc_exec_ctx_flush(exec_ctx);
       grpc_iomgr_platform_flush();
diff --git a/src/core/lib/iomgr/iomgr.h b/src/core/lib/iomgr/iomgr.h
index e3cd6ebe79..fea08496fe 100644
--- a/src/core/lib/iomgr/iomgr.h
+++ b/src/core/lib/iomgr/iomgr.h
@@ -22,6 +22,10 @@
 #include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include "src/core/lib/iomgr/port.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** Initializes the iomgr. */
 void grpc_iomgr_init(grpc_exec_ctx *exec_ctx);
 
@@ -32,4 +36,8 @@ void grpc_iomgr_start(grpc_exec_ctx *exec_ctx);
  * exec_ctx. */
 void grpc_iomgr_shutdown(grpc_exec_ctx *exec_ctx);
 
-#endif /* GRPC_CORE_LIB_IOMGR_IOMGR_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_IOMGR_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/iomgr_internal.h b/src/core/lib/iomgr/iomgr_internal.h
index 836d82515d..005abbed13 100644
--- a/src/core/lib/iomgr/iomgr_internal.h
+++ b/src/core/lib/iomgr/iomgr_internal.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/iomgr/iomgr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_iomgr_object {
   char *name;
   struct grpc_iomgr_object *next;
@@ -40,4 +44,8 @@ void grpc_iomgr_platform_shutdown(void);
 
 bool grpc_iomgr_abort_on_leaks(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_IOMGR_INTERNAL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_IOMGR_INTERNAL_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/iomgr_posix.c b/src/core/lib/iomgr/iomgr_posix.cc
index f5875a247e..f5875a247e 100644
--- a/src/core/lib/iomgr/iomgr_posix.c
+++ b/src/core/lib/iomgr/iomgr_posix.cc
diff --git a/src/core/lib/iomgr/iomgr_uv.c b/src/core/lib/iomgr/iomgr_uv.cc
index df5d23af3b..df5d23af3b 100644
--- a/src/core/lib/iomgr/iomgr_uv.c
+++ b/src/core/lib/iomgr/iomgr_uv.cc
diff --git a/src/core/lib/iomgr/iomgr_uv.h b/src/core/lib/iomgr/iomgr_uv.h
index 3b4daaa73b..bc42ca8c1c 100644
--- a/src/core/lib/iomgr/iomgr_uv.h
+++ b/src/core/lib/iomgr/iomgr_uv.h
@@ -23,10 +23,18 @@
 
 #include <grpc/support/thd.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* The thread ID of the thread on which grpc was initialized. Used to verify
  * that all calls into libuv are made on that same thread */
 extern gpr_thd_id g_init_thread;
 
+#ifdef __cplusplus
+}
+#endif
+
 #ifdef GRPC_UV_THREAD_CHECK
 #define GRPC_UV_ASSERT_SAME_THREAD() \
   GPR_ASSERT(gpr_thd_currentid() == g_init_thread)
diff --git a/src/core/lib/iomgr/iomgr_windows.c b/src/core/lib/iomgr/iomgr_windows.cc
index 630370166d..630370166d 100644
--- a/src/core/lib/iomgr/iomgr_windows.c
+++ b/src/core/lib/iomgr/iomgr_windows.cc
diff --git a/src/core/lib/iomgr/is_epollexclusive_available.c b/src/core/lib/iomgr/is_epollexclusive_available.cc
index d08844c0df..d08844c0df 100644
--- a/src/core/lib/iomgr/is_epollexclusive_available.c
+++ b/src/core/lib/iomgr/is_epollexclusive_available.cc
diff --git a/src/core/lib/iomgr/is_epollexclusive_available.h b/src/core/lib/iomgr/is_epollexclusive_available.h
index 1d2e133a3b..5c3e483065 100644
--- a/src/core/lib/iomgr/is_epollexclusive_available.h
+++ b/src/core/lib/iomgr/is_epollexclusive_available.h
@@ -21,6 +21,14 @@
 
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 bool grpc_is_epollexclusive_available(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_IS_EPOLLEXCLUSIVE_AVAILABLE_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_IS_EPOLLEXCLUSIVE_AVAILABLE_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/load_file.c b/src/core/lib/iomgr/load_file.cc
index 0b4d41ea4b..5cb4099ea4 100644
--- a/src/core/lib/iomgr/load_file.c
+++ b/src/core/lib/iomgr/load_file.cc
@@ -25,7 +25,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/lib/support/block_annotate.h"
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/support/string.h"
 
 grpc_error *grpc_load_file(const char *filename, int add_null_terminator,
@@ -73,6 +73,6 @@ end:
     GRPC_ERROR_UNREF(error);
     error = error_out;
   }
-  GRPC_SCHEDULING_END_BLOCKING_REGION;
+  GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX;
   return error;
 }
diff --git a/src/core/lib/iomgr/lockfree_event.c b/src/core/lib/iomgr/lockfree_event.cc
index f967b22ba9..f967b22ba9 100644
--- a/src/core/lib/iomgr/lockfree_event.c
+++ b/src/core/lib/iomgr/lockfree_event.cc
diff --git a/src/core/lib/iomgr/lockfree_event.h b/src/core/lib/iomgr/lockfree_event.h
index 6a14a0f3b2..925f004945 100644
--- a/src/core/lib/iomgr/lockfree_event.h
+++ b/src/core/lib/iomgr/lockfree_event.h
@@ -25,6 +25,10 @@
 
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void grpc_lfev_init(gpr_atm *state);
 void grpc_lfev_destroy(gpr_atm *state);
 bool grpc_lfev_is_shutdown(gpr_atm *state);
@@ -37,4 +41,8 @@ bool grpc_lfev_set_shutdown(grpc_exec_ctx *exec_ctx, gpr_atm *state,
 void grpc_lfev_set_ready(grpc_exec_ctx *exec_ctx, gpr_atm *state,
                          const char *variable);
 
-#endif /* GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_LOCKFREE_EVENT_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/network_status_tracker.c b/src/core/lib/iomgr/network_status_tracker.cc
index 4e5c1d5408..57a7faa9f1 100644
--- a/src/core/lib/iomgr/network_status_tracker.c
+++ b/src/core/lib/iomgr/network_status_tracker.cc
@@ -16,6 +16,7 @@
  *
  */
 
+#include "src/core/lib/iomgr/network_status_tracker.h"
 #include "src/core/lib/iomgr/endpoint.h"
 
 void grpc_network_status_shutdown(void) {}
diff --git a/src/core/lib/iomgr/network_status_tracker.h b/src/core/lib/iomgr/network_status_tracker.h
index c0295c1f74..af50d51257 100644
--- a/src/core/lib/iomgr/network_status_tracker.h
+++ b/src/core/lib/iomgr/network_status_tracker.h
@@ -20,6 +20,10 @@
 #define GRPC_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H
 #include "src/core/lib/iomgr/endpoint.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void grpc_network_status_init(void);
 void grpc_network_status_shutdown(void);
 
@@ -27,4 +31,8 @@ void grpc_network_status_register_endpoint(grpc_endpoint *ep);
 void grpc_network_status_unregister_endpoint(grpc_endpoint *ep);
 void grpc_network_status_shutdown_all_endpoints();
 
-#endif /* GRPC_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_NETWORK_STATUS_TRACKER_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/polling_entity.c b/src/core/lib/iomgr/polling_entity.cc
index 8591a5518e..8591a5518e 100644
--- a/src/core/lib/iomgr/polling_entity.c
+++ b/src/core/lib/iomgr/polling_entity.cc
diff --git a/src/core/lib/iomgr/polling_entity.h b/src/core/lib/iomgr/polling_entity.h
index a161e1fea6..4a37acf212 100644
--- a/src/core/lib/iomgr/polling_entity.h
+++ b/src/core/lib/iomgr/polling_entity.h
@@ -22,6 +22,10 @@
 #include "src/core/lib/iomgr/pollset.h"
 #include "src/core/lib/iomgr/pollset_set.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum grpc_pollset_tag {
   GRPC_POLLS_NONE,
   GRPC_POLLS_POLLSET,
@@ -64,4 +68,8 @@ void grpc_polling_entity_add_to_pollset_set(grpc_exec_ctx *exec_ctx,
 void grpc_polling_entity_del_from_pollset_set(grpc_exec_ctx *exec_ctx,
                                               grpc_polling_entity *pollent,
                                               grpc_pollset_set *pss_dst);
-#endif /* GRPC_CORE_LIB_IOMGR_POLLING_ENTITY_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_POLLING_ENTITY_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/pollset.h b/src/core/lib/iomgr/pollset.h
index a0f6b3a9d3..799fae154c 100644
--- a/src/core/lib/iomgr/pollset.h
+++ b/src/core/lib/iomgr/pollset.h
@@ -25,6 +25,10 @@
 
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef NDEBUG
 extern grpc_tracer_flag grpc_trace_fd_refcount;
 #endif
@@ -71,8 +75,8 @@ void grpc_pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset);
    pollset
    lock */
 grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                              grpc_pollset_worker **worker, gpr_timespec now,
-                              gpr_timespec deadline) GRPC_MUST_USE_RESULT;
+                              grpc_pollset_worker **worker,
+                              grpc_millis deadline) GRPC_MUST_USE_RESULT;
 
 /* Break one polling thread out of polling work for this pollset.
    If specific_worker is non-NULL, then kick that worker. */
@@ -80,4 +84,8 @@ grpc_error *grpc_pollset_kick(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                               grpc_pollset_worker *specific_worker)
     GRPC_MUST_USE_RESULT;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_POLLSET_H */
diff --git a/src/core/lib/iomgr/pollset_set.h b/src/core/lib/iomgr/pollset_set.h
index 29c0f03561..17df86542d 100644
--- a/src/core/lib/iomgr/pollset_set.h
+++ b/src/core/lib/iomgr/pollset_set.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/iomgr/pollset.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* A grpc_pollset_set is a set of pollsets that are interested in an
    action. Adding a pollset to a pollset_set automatically adds any
    fd's (etc) that have been registered with the set_set to that pollset.
@@ -44,4 +48,8 @@ void grpc_pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
                                       grpc_pollset_set *bag,
                                       grpc_pollset_set *item);
 
-#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_SET_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_SET_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/pollset_set_uv.c b/src/core/lib/iomgr/pollset_set_uv.cc
index 90186edbb7..90186edbb7 100644
--- a/src/core/lib/iomgr/pollset_set_uv.c
+++ b/src/core/lib/iomgr/pollset_set_uv.cc
diff --git a/src/core/lib/iomgr/pollset_set_windows.c b/src/core/lib/iomgr/pollset_set_windows.cc
index 2105a47ad4..2105a47ad4 100644
--- a/src/core/lib/iomgr/pollset_set_windows.c
+++ b/src/core/lib/iomgr/pollset_set_windows.cc
diff --git a/src/core/lib/iomgr/pollset_uv.c b/src/core/lib/iomgr/pollset_uv.cc
index 2651325e25..b9901bf8ef 100644
--- a/src/core/lib/iomgr/pollset_uv.c
+++ b/src/core/lib/iomgr/pollset_uv.cc
@@ -65,7 +65,7 @@ void dummy_handle_close_cb(uv_handle_t *handle) { gpr_free(handle); }
 
 void grpc_pollset_global_init(void) {
   gpr_mu_init(&grpc_polling_mu);
-  dummy_uv_handle = gpr_malloc(sizeof(uv_timer_t));
+  dummy_uv_handle = (uv_timer_t *)gpr_malloc(sizeof(uv_timer_t));
   uv_timer_init(uv_default_loop(), dummy_uv_handle);
   grpc_pollset_work_run_loop = 1;
 }
@@ -116,13 +116,14 @@ void grpc_pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {
 
 grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                               grpc_pollset_worker **worker_hdl,
-                              gpr_timespec now, gpr_timespec deadline) {
+                              grpc_millis deadline) {
   uint64_t timeout;
   GRPC_UV_ASSERT_SAME_THREAD();
   gpr_mu_unlock(&grpc_polling_mu);
   if (grpc_pollset_work_run_loop) {
-    if (gpr_time_cmp(deadline, now) >= 0) {
-      timeout = (uint64_t)gpr_time_to_millis(gpr_time_sub(deadline, now));
+    grpc_millis now = grpc_exec_ctx_now(exec_ctx);
+    if (deadline >= now) {
+      timeout = deadline - now;
     } else {
       timeout = 0;
     }
diff --git a/src/core/lib/iomgr/pollset_uv.h b/src/core/lib/iomgr/pollset_uv.h
index 566c110ca6..d8f72ff867 100644
--- a/src/core/lib/iomgr/pollset_uv.h
+++ b/src/core/lib/iomgr/pollset_uv.h
@@ -19,9 +19,17 @@
 #ifndef GRPC_CORE_LIB_IOMGR_POLLSET_UV_H
 #define GRPC_CORE_LIB_IOMGR_POLLSET_UV_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern int grpc_pollset_work_run_loop;
 
 void grpc_pollset_global_init(void);
 void grpc_pollset_global_shutdown(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_UV_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_UV_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/pollset_windows.c b/src/core/lib/iomgr/pollset_windows.cc
index eb295d3eeb..bb4df83fc1 100644
--- a/src/core/lib/iomgr/pollset_windows.c
+++ b/src/core/lib/iomgr/pollset_windows.cc
@@ -110,7 +110,7 @@ void grpc_pollset_destroy(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {}
 
 grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                               grpc_pollset_worker **worker_hdl,
-                              gpr_timespec now, gpr_timespec deadline) {
+                              grpc_millis deadline) {
   grpc_pollset_worker worker;
   if (worker_hdl) *worker_hdl = &worker;
 
@@ -159,7 +159,8 @@ grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                       &worker);
     added_worker = 1;
     while (!worker.kicked) {
-      if (gpr_cv_wait(&worker.cv, &grpc_polling_mu, deadline)) {
+      if (gpr_cv_wait(&worker.cv, &grpc_polling_mu,
+                      grpc_millis_to_timespec(deadline, GPR_CLOCK_REALTIME))) {
         break;
       }
     }
diff --git a/src/core/lib/iomgr/pollset_windows.h b/src/core/lib/iomgr/pollset_windows.h
index 71878c3d30..7733d26471 100644
--- a/src/core/lib/iomgr/pollset_windows.h
+++ b/src/core/lib/iomgr/pollset_windows.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/iomgr/socket_windows.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* There isn't really any such thing as a pollset under Windows, due to the
    nature of the IO completion ports. A Windows "pollset" is merely a mutex
    used to synchronize with the IOCP, and workers are condition variables
@@ -60,4 +64,8 @@ struct grpc_pollset {
 void grpc_pollset_global_init(void);
 void grpc_pollset_global_shutdown(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_WINDOWS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_POLLSET_WINDOWS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/resolve_address.h b/src/core/lib/iomgr/resolve_address.h
index fe1dd78576..4a6df2cf26 100644
--- a/src/core/lib/iomgr/resolve_address.h
+++ b/src/core/lib/iomgr/resolve_address.h
@@ -25,6 +25,10 @@
 
 #define GRPC_MAX_SOCKADDR_SIZE 128
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
   char addr[GRPC_MAX_SOCKADDR_SIZE];
   size_t len;
@@ -52,4 +56,8 @@ extern grpc_error *(*grpc_blocking_resolve_address)(
     const char *name, const char *default_port,
     grpc_resolved_addresses **addresses);
 
-#endif /* GRPC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_RESOLVE_ADDRESS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/resolve_address_posix.c b/src/core/lib/iomgr/resolve_address_posix.cc
index 60cfeebd47..1b783495df 100644
--- a/src/core/lib/iomgr/resolve_address_posix.c
+++ b/src/core/lib/iomgr/resolve_address_posix.cc
@@ -33,10 +33,10 @@
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
 #include <grpc/support/useful.h>
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/string.h"
 
 static grpc_error *blocking_resolve_address_impl(
@@ -81,7 +81,7 @@ static grpc_error *blocking_resolve_address_impl(
 
   GRPC_SCHEDULING_START_BLOCKING_REGION;
   s = getaddrinfo(host, port, &hints, &result);
-  GRPC_SCHEDULING_END_BLOCKING_REGION;
+  GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX;
 
   if (s != 0) {
     /* Retry if well-known service name is recognized */
@@ -90,7 +90,7 @@ static grpc_error *blocking_resolve_address_impl(
       if (strcmp(port, svc[i][0]) == 0) {
         GRPC_SCHEDULING_START_BLOCKING_REGION;
         s = getaddrinfo(host, svc[i][1], &hints, &result);
-        GRPC_SCHEDULING_END_BLOCKING_REGION;
+        GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX;
         break;
       }
     }
diff --git a/src/core/lib/iomgr/resolve_address_uv.c b/src/core/lib/iomgr/resolve_address_uv.cc
index 2d438e8b48..4f7f234877 100644
--- a/src/core/lib/iomgr/resolve_address_uv.c
+++ b/src/core/lib/iomgr/resolve_address_uv.cc
@@ -49,11 +49,12 @@ static int retry_named_port_failure(int status, request *r,
                                     uv_getaddrinfo_cb getaddrinfo_cb) {
   if (status != 0) {
     // This loop is copied from resolve_address_posix.c
-    char *svc[][2] = {{"http", "80"}, {"https", "443"}};
+    const char *svc[][2] = {{"http", "80"}, {"https", "443"}};
     for (size_t i = 0; i < GPR_ARRAY_SIZE(svc); i++) {
       if (strcmp(r->port, svc[i][0]) == 0) {
         int retry_status;
-        uv_getaddrinfo_t *req = gpr_malloc(sizeof(uv_getaddrinfo_t));
+        uv_getaddrinfo_t *req =
+            (uv_getaddrinfo_t *)gpr_malloc(sizeof(uv_getaddrinfo_t));
         req->data = r;
         r->port = gpr_strdup(svc[i][1]);
         retry_status = uv_getaddrinfo(uv_default_loop(), req, getaddrinfo_cb,
@@ -85,13 +86,14 @@ static grpc_error *handle_addrinfo_result(int status, struct addrinfo *result,
                            grpc_slice_from_static_string(uv_strerror(status)));
     return error;
   }
-  (*addresses) = gpr_malloc(sizeof(grpc_resolved_addresses));
+  (*addresses) =
+      (grpc_resolved_addresses *)gpr_malloc(sizeof(grpc_resolved_addresses));
   (*addresses)->naddrs = 0;
   for (resp = result; resp != NULL; resp = resp->ai_next) {
     (*addresses)->naddrs++;
   }
-  (*addresses)->addrs =
-      gpr_malloc(sizeof(grpc_resolved_address) * (*addresses)->naddrs);
+  (*addresses)->addrs = (grpc_resolved_address *)gpr_malloc(
+      sizeof(grpc_resolved_address) * (*addresses)->naddrs);
   i = 0;
   for (resp = result; resp != NULL; resp = resp->ai_next) {
     memcpy(&(*addresses)->addrs[i].addr, resp->ai_addr, resp->ai_addrlen);
@@ -174,6 +176,7 @@ static grpc_error *blocking_resolve_address_impl(
   int s;
   grpc_error *err;
   int retry_status;
+  request r;
 
   GRPC_UV_ASSERT_SAME_THREAD();
 
@@ -191,8 +194,10 @@ static grpc_error *blocking_resolve_address_impl(
   hints.ai_flags = AI_PASSIVE;     /* for wildcard IP address */
 
   s = uv_getaddrinfo(uv_default_loop(), &req, NULL, host, port, &hints);
-  request r = {
-      .addresses = addresses, .hints = &hints, .host = host, .port = port};
+  r.addresses = addresses;
+  r.hints = &hints;
+  r.host = host;
+  r.port = port;
   retry_status = retry_named_port_failure(s, &r, NULL);
   if (retry_status <= 0) {
     s = retry_status;
@@ -239,16 +244,16 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
     gpr_free(port);
     return;
   }
-  r = gpr_malloc(sizeof(request));
+  r = (request *)gpr_malloc(sizeof(request));
   r->on_done = on_done;
   r->addresses = addrs;
   r->host = host;
   r->port = port;
-  req = gpr_malloc(sizeof(uv_getaddrinfo_t));
+  req = (uv_getaddrinfo_t *)gpr_malloc(sizeof(uv_getaddrinfo_t));
   req->data = r;
 
   /* Call getaddrinfo */
-  hints = gpr_malloc(sizeof(struct addrinfo));
+  hints = (addrinfo *)gpr_malloc(sizeof(struct addrinfo));
   memset(hints, 0, sizeof(struct addrinfo));
   hints->ai_family = AF_UNSPEC;     /* ipv4 or ipv6 */
   hints->ai_socktype = SOCK_STREAM; /* stream socket */
diff --git a/src/core/lib/iomgr/resolve_address_windows.c b/src/core/lib/iomgr/resolve_address_windows.cc
index 0cb0029f4e..451f01a701 100644
--- a/src/core/lib/iomgr/resolve_address_windows.c
+++ b/src/core/lib/iomgr/resolve_address_windows.cc
@@ -23,6 +23,7 @@
 
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#include <inttypes.h>
 #include <string.h>
 #include <sys/types.h>
 
@@ -33,10 +34,10 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
+#include "src/core/lib/iomgr/block_annotate.h"
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/string.h"
 
 typedef struct {
@@ -86,20 +87,21 @@ static grpc_error *blocking_resolve_address_impl(
 
   GRPC_SCHEDULING_START_BLOCKING_REGION;
   s = getaddrinfo(host, port, &hints, &result);
-  GRPC_SCHEDULING_END_BLOCKING_REGION;
+  GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX;
   if (s != 0) {
     error = GRPC_WSA_ERROR(WSAGetLastError(), "getaddrinfo");
     goto done;
   }
 
   /* Success path: set addrs non-NULL, fill it in */
-  (*addresses) = gpr_malloc(sizeof(grpc_resolved_addresses));
+  (*addresses) =
+      (grpc_resolved_addresses *)gpr_malloc(sizeof(grpc_resolved_addresses));
   (*addresses)->naddrs = 0;
   for (resp = result; resp != NULL; resp = resp->ai_next) {
     (*addresses)->naddrs++;
   }
-  (*addresses)->addrs =
-      gpr_malloc(sizeof(grpc_resolved_address) * (*addresses)->naddrs);
+  (*addresses)->addrs = (grpc_resolved_address *)gpr_malloc(
+      sizeof(grpc_resolved_address) * (*addresses)->naddrs);
   i = 0;
   for (resp = result; resp != NULL; resp = resp->ai_next) {
     memcpy(&(*addresses)->addrs[i].addr, resp->ai_addr, resp->ai_addrlen);
@@ -132,7 +134,7 @@ grpc_error *(*grpc_blocking_resolve_address)(
  * grpc_blocking_resolve_address */
 static void do_request_thread(grpc_exec_ctx *exec_ctx, void *rp,
                               grpc_error *error) {
-  request *r = rp;
+  request *r = (request *)rp;
   if (error == GRPC_ERROR_NONE) {
     error =
         grpc_blocking_resolve_address(r->name, r->default_port, r->addresses);
@@ -157,7 +159,7 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  grpc_pollset_set *interested_parties,
                                  grpc_closure *on_done,
                                  grpc_resolved_addresses **addresses) {
-  request *r = gpr_malloc(sizeof(request));
+  request *r = (request *)gpr_malloc(sizeof(request));
   GRPC_CLOSURE_INIT(&r->request_closure, do_request_thread, r,
                     grpc_executor_scheduler(GRPC_EXECUTOR_SHORT));
   r->name = gpr_strdup(name);
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.cc
index 4d69986fbc..ecb5747da8 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.cc
@@ -18,6 +18,7 @@
 
 #include "src/core/lib/iomgr/resource_quota.h"
 
+#include <inttypes.h>
 #include <limits.h>
 #include <stdint.h>
 #include <string.h>
@@ -88,6 +89,8 @@ struct grpc_resource_user {
   grpc_closure_list on_allocated;
   /* True if we are currently trying to allocate from the quota, false if not */
   bool allocating;
+  /* How many bytes of allocations are outstanding */
+  int64_t outstanding_allocations;
   /* True if we are currently trying to add ourselves to the non-free quota
      list, false otherwise */
   bool added_to_free_pool;
@@ -152,6 +155,9 @@ struct grpc_resource_quota {
   char *name;
 };
 
+static void ru_unref_by(grpc_exec_ctx *exec_ctx,
+                        grpc_resource_user *resource_user, gpr_atm amount);
+
 /*******************************************************************************
  * list management
  */
@@ -288,6 +294,25 @@ static bool rq_alloc(grpc_exec_ctx *exec_ctx,
   while ((resource_user = rulist_pop_head(resource_quota,
                                           GRPC_RULIST_AWAITING_ALLOCATION))) {
     gpr_mu_lock(&resource_user->mu);
+    if (GRPC_TRACER_ON(grpc_resource_quota_trace)) {
+      gpr_log(GPR_DEBUG, "RQ: check allocation for user %p shutdown=%" PRIdPTR
+                         " free_pool=%" PRId64,
+              resource_user, gpr_atm_no_barrier_load(&resource_user->shutdown),
+              resource_user->free_pool);
+    }
+    if (gpr_atm_no_barrier_load(&resource_user->shutdown)) {
+      resource_user->allocating = false;
+      grpc_closure_list_fail_all(
+          &resource_user->on_allocated,
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Resource user shutdown"));
+      int64_t aborted_allocations = resource_user->outstanding_allocations;
+      resource_user->outstanding_allocations = 0;
+      resource_user->free_pool += aborted_allocations;
+      GRPC_CLOSURE_LIST_SCHED(exec_ctx, &resource_user->on_allocated);
+      gpr_mu_unlock(&resource_user->mu);
+      ru_unref_by(exec_ctx, resource_user, (gpr_atm)aborted_allocations);
+      continue;
+    }
     if (resource_user->free_pool < 0 &&
         -resource_user->free_pool <= resource_quota->free_pool) {
       int64_t amt = -resource_user->free_pool;
@@ -307,6 +332,7 @@ static bool rq_alloc(grpc_exec_ctx *exec_ctx,
     }
     if (resource_user->free_pool >= 0) {
       resource_user->allocating = false;
+      resource_user->outstanding_allocations = 0;
       GRPC_CLOSURE_LIST_SCHED(exec_ctx, &resource_user->on_allocated);
       gpr_mu_unlock(&resource_user->mu);
     } else {
@@ -487,6 +513,9 @@ static void ru_post_destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *ru,
 }
 
 static void ru_shutdown(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
+  if (GRPC_TRACER_ON(grpc_resource_quota_trace)) {
+    gpr_log(GPR_DEBUG, "RU shutdown %p", ru);
+  }
   grpc_resource_user *resource_user = (grpc_resource_user *)ru;
   GRPC_CLOSURE_SCHED(exec_ctx, resource_user->reclaimers[0],
                      GRPC_ERROR_CANCELLED);
@@ -496,6 +525,9 @@ static void ru_shutdown(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
   resource_user->reclaimers[1] = NULL;
   rulist_remove(resource_user, GRPC_RULIST_RECLAIMER_BENIGN);
   rulist_remove(resource_user, GRPC_RULIST_RECLAIMER_DESTRUCTIVE);
+  if (resource_user->allocating) {
+    rq_step_sched(exec_ctx, resource_user->resource_quota);
+  }
 }
 
 static void ru_destroy(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
@@ -717,6 +749,7 @@ grpc_resource_user *grpc_resource_user_create(
   resource_user->reclaimers[1] = NULL;
   resource_user->new_reclaimers[0] = NULL;
   resource_user->new_reclaimers[1] = NULL;
+  resource_user->outstanding_allocations = 0;
   for (int i = 0; i < GRPC_RULIST_COUNT; i++) {
     resource_user->links[i].next = resource_user->links[i].prev = NULL;
   }
@@ -777,6 +810,7 @@ void grpc_resource_user_alloc(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&resource_user->mu);
   ru_ref_by(resource_user, (gpr_atm)size);
   resource_user->free_pool -= (int64_t)size;
+  resource_user->outstanding_allocations += (int64_t)size;
   if (GRPC_TRACER_ON(grpc_resource_quota_trace)) {
     gpr_log(GPR_DEBUG, "RQ %s %s: alloc %" PRIdPTR "; free_pool -> %" PRId64,
             resource_user->resource_quota->name, resource_user->name, size,
@@ -791,6 +825,7 @@ void grpc_resource_user_alloc(grpc_exec_ctx *exec_ctx,
                          GRPC_ERROR_NONE);
     }
   } else {
+    resource_user->outstanding_allocations -= (int64_t)size;
     GRPC_CLOSURE_SCHED(exec_ctx, optional_on_done, GRPC_ERROR_NONE);
   }
   gpr_mu_unlock(&resource_user->mu);
diff --git a/src/core/lib/iomgr/resource_quota.h b/src/core/lib/iomgr/resource_quota.h
index d66f9ae774..3afb525434 100644
--- a/src/core/lib/iomgr/resource_quota.h
+++ b/src/core/lib/iomgr/resource_quota.h
@@ -24,6 +24,10 @@
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** \file Tracks resource usage against a pool.
 
     The current implementation tracks only memory usage, but in the future
@@ -150,4 +154,8 @@ grpc_slice grpc_resource_user_slice_malloc(grpc_exec_ctx *exec_ctx,
                                            grpc_resource_user *resource_user,
                                            size_t size);
 
-#endif /* GRPC_CORE_LIB_IOMGR_RESOURCE_QUOTA_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_RESOURCE_QUOTA_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/sockaddr_utils.c b/src/core/lib/iomgr/sockaddr_utils.cc
index 3f4145d104..8a2e6ed89b 100644
--- a/src/core/lib/iomgr/sockaddr_utils.c
+++ b/src/core/lib/iomgr/sockaddr_utils.cc
@@ -19,6 +19,7 @@
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 
 #include <errno.h>
+#include <inttypes.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
diff --git a/src/core/lib/iomgr/sockaddr_utils.h b/src/core/lib/iomgr/sockaddr_utils.h
index a589a19705..129bb54fc9 100644
--- a/src/core/lib/iomgr/sockaddr_utils.h
+++ b/src/core/lib/iomgr/sockaddr_utils.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Returns true if addr is an IPv4-mapped IPv6 address within the
    ::ffff:0.0.0.0/96 range, or false otherwise.
 
@@ -77,4 +81,8 @@ const char *grpc_sockaddr_get_uri_scheme(const grpc_resolved_address *addr);
 
 int grpc_sockaddr_get_family(const grpc_resolved_address *resolved_addr);
 
-#endif /* GRPC_CORE_LIB_IOMGR_SOCKADDR_UTILS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_SOCKADDR_UTILS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/socket_factory_posix.c b/src/core/lib/iomgr/socket_factory_posix.cc
index 8e907703ae..8e907703ae 100644
--- a/src/core/lib/iomgr/socket_factory_posix.c
+++ b/src/core/lib/iomgr/socket_factory_posix.cc
diff --git a/src/core/lib/iomgr/socket_mutator.c b/src/core/lib/iomgr/socket_mutator.cc
index b0435d5a07..b0435d5a07 100644
--- a/src/core/lib/iomgr/socket_mutator.c
+++ b/src/core/lib/iomgr/socket_mutator.cc
diff --git a/src/core/lib/iomgr/socket_utils.h b/src/core/lib/iomgr/socket_utils.h
index 03fe46e5e9..f319e931b6 100644
--- a/src/core/lib/iomgr/socket_utils.h
+++ b/src/core/lib/iomgr/socket_utils.h
@@ -21,7 +21,15 @@
 
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* A wrapper for inet_ntop on POSIX systems and InetNtop on Windows systems */
 const char *grpc_inet_ntop(int af, const void *src, char *dst, size_t size);
 
-#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_UTILS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_UTILS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/socket_utils_common_posix.c b/src/core/lib/iomgr/socket_utils_common_posix.cc
index b8e2a0cdfd..b8e2a0cdfd 100644
--- a/src/core/lib/iomgr/socket_utils_common_posix.c
+++ b/src/core/lib/iomgr/socket_utils_common_posix.cc
diff --git a/src/core/lib/iomgr/socket_utils_linux.c b/src/core/lib/iomgr/socket_utils_linux.cc
index e7b094d216..e7b094d216 100644
--- a/src/core/lib/iomgr/socket_utils_linux.c
+++ b/src/core/lib/iomgr/socket_utils_linux.cc
diff --git a/src/core/lib/iomgr/socket_utils_posix.c b/src/core/lib/iomgr/socket_utils_posix.cc
index dfd1ffd1e3..dfd1ffd1e3 100644
--- a/src/core/lib/iomgr/socket_utils_posix.c
+++ b/src/core/lib/iomgr/socket_utils_posix.cc
diff --git a/src/core/lib/iomgr/socket_utils_posix.h b/src/core/lib/iomgr/socket_utils_posix.h
index eef80b439e..623b83f08b 100644
--- a/src/core/lib/iomgr/socket_utils_posix.h
+++ b/src/core/lib/iomgr/socket_utils_posix.h
@@ -29,6 +29,10 @@
 #include "src/core/lib/iomgr/socket_factory_posix.h"
 #include "src/core/lib/iomgr/socket_mutator.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* a wrapper for accept or accept4 */
 int grpc_accept4(int sockfd, grpc_resolved_address *resolved_addr, int nonblock,
                  int cloexec);
@@ -129,4 +133,8 @@ grpc_error *grpc_create_dualstack_socket_using_factory(
     grpc_socket_factory *factory, const grpc_resolved_address *addr, int type,
     int protocol, grpc_dualstack_mode *dsmode, int *newfd);
 
-#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_UTILS_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_UTILS_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/socket_utils_uv.c b/src/core/lib/iomgr/socket_utils_uv.cc
index 0f7de4dfad..0f7de4dfad 100644
--- a/src/core/lib/iomgr/socket_utils_uv.c
+++ b/src/core/lib/iomgr/socket_utils_uv.cc
diff --git a/src/core/lib/iomgr/socket_utils_windows.c b/src/core/lib/iomgr/socket_utils_windows.cc
index 2732c159aa..6e85e4b61f 100644
--- a/src/core/lib/iomgr/socket_utils_windows.c
+++ b/src/core/lib/iomgr/socket_utils_windows.cc
@@ -26,12 +26,8 @@
 #include <grpc/support/log.h>
 
 const char *grpc_inet_ntop(int af, const void *src, char *dst, size_t size) {
-#ifdef GPR_WIN_INET_NTOP
-  return inet_ntop(af, src, dst, size);
-#else
   /* Windows InetNtopA wants a mutable ip pointer */
   return InetNtopA(af, (void *)src, dst, size);
-#endif /* GPR_WIN_INET_NTOP */
 }
 
 #endif /* GRPC_WINDOWS_SOCKETUTILS */
diff --git a/src/core/lib/iomgr/socket_windows.c b/src/core/lib/iomgr/socket_windows.cc
index a0d731b942..8c7f7cf683 100644
--- a/src/core/lib/iomgr/socket_windows.c
+++ b/src/core/lib/iomgr/socket_windows.cc
@@ -38,7 +38,7 @@
 
 grpc_winsocket *grpc_winsocket_create(SOCKET socket, const char *name) {
   char *final_name;
-  grpc_winsocket *r = gpr_malloc(sizeof(grpc_winsocket));
+  grpc_winsocket *r = (grpc_winsocket *)gpr_malloc(sizeof(grpc_winsocket));
   memset(r, 0, sizeof(grpc_winsocket));
   r->socket = socket;
   gpr_mu_init(&r->state_mu);
diff --git a/src/core/lib/iomgr/socket_windows.h b/src/core/lib/iomgr/socket_windows.h
index 67dc4ca53e..a00a7615a3 100644
--- a/src/core/lib/iomgr/socket_windows.h
+++ b/src/core/lib/iomgr/socket_windows.h
@@ -28,6 +28,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* This holds the data for an outstanding read or write on a socket.
    The mutex to protect the concurrent access to that data is the one
    inside the winsocket wrapper. */
@@ -107,4 +111,8 @@ void grpc_socket_become_ready(grpc_exec_ctx *exec_ctx,
                               grpc_winsocket *winsocket,
                               grpc_winsocket_callback_info *ci);
 
-#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_WINDOWS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_SOCKET_WINDOWS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_client.h b/src/core/lib/iomgr/tcp_client.h
index 6c9e51ae84..1b102b5784 100644
--- a/src/core/lib/iomgr/tcp_client.h
+++ b/src/core/lib/iomgr/tcp_client.h
@@ -25,6 +25,10 @@
 #include "src/core/lib/iomgr/pollset_set.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Asynchronously connect to an address (specified as (addr, len)), and call
    cb with arg and the completed connection when done (or call cb with arg and
    NULL on failure).
@@ -35,6 +39,10 @@ void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *on_connect,
                              grpc_pollset_set *interested_parties,
                              const grpc_channel_args *channel_args,
                              const grpc_resolved_address *addr,
-                             gpr_timespec deadline);
+                             grpc_millis deadline);
+
+#ifdef __cplusplus
+}
+#endif
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_CLIENT_H */
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_CLIENT_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_client_posix.c b/src/core/lib/iomgr/tcp_client_posix.cc
index 39dbb506e2..5611dd9062 100644
--- a/src/core/lib/iomgr/tcp_client_posix.c
+++ b/src/core/lib/iomgr/tcp_client_posix.cc
@@ -48,7 +48,6 @@ extern grpc_tracer_flag grpc_tcp_trace;
 typedef struct {
   gpr_mu mu;
   grpc_fd *fd;
-  gpr_timespec deadline;
   grpc_timer alarm;
   grpc_closure on_alarm;
   int refs;
@@ -244,7 +243,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
                                     grpc_pollset_set *interested_parties,
                                     const grpc_channel_args *channel_args,
                                     const grpc_resolved_address *addr,
-                                    gpr_timespec deadline) {
+                                    grpc_millis deadline) {
   int fd;
   grpc_dualstack_mode dsmode;
   int err;
@@ -325,9 +324,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
 
   gpr_mu_lock(&ac->mu);
   GRPC_CLOSURE_INIT(&ac->on_alarm, tc_on_alarm, ac, grpc_schedule_on_exec_ctx);
-  grpc_timer_init(exec_ctx, &ac->alarm,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  &ac->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_timer_init(exec_ctx, &ac->alarm, deadline, &ac->on_alarm);
   grpc_fd_notify_on_write(exec_ctx, ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);
 
@@ -337,18 +334,20 @@ done:
 }
 
 // overridden by api_fuzzer.c
+extern "C" {
 void (*grpc_tcp_client_connect_impl)(
     grpc_exec_ctx *exec_ctx, grpc_closure *closure, grpc_endpoint **ep,
     grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
     const grpc_resolved_address *addr,
-    gpr_timespec deadline) = tcp_client_connect_impl;
+    grpc_millis deadline) = tcp_client_connect_impl;
+}
 
 void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                              grpc_endpoint **ep,
                              grpc_pollset_set *interested_parties,
                              const grpc_channel_args *channel_args,
                              const grpc_resolved_address *addr,
-                             gpr_timespec deadline) {
+                             grpc_millis deadline) {
   grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
                                channel_args, addr, deadline);
 }
diff --git a/src/core/lib/iomgr/tcp_client_posix.h b/src/core/lib/iomgr/tcp_client_posix.h
index b5a3814799..0b9775504c 100644
--- a/src/core/lib/iomgr/tcp_client_posix.h
+++ b/src/core/lib/iomgr/tcp_client_posix.h
@@ -23,8 +23,16 @@
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/tcp_client.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_endpoint *grpc_tcp_client_create_from_fd(
     grpc_exec_ctx *exec_ctx, grpc_fd *fd, const grpc_channel_args *channel_args,
     const char *addr_str);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_CLIENT_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_CLIENT_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_client_uv.c b/src/core/lib/iomgr/tcp_client_uv.cc
index 786c456b73..f3e9366299 100644
--- a/src/core/lib/iomgr/tcp_client_uv.c
+++ b/src/core/lib/iomgr/tcp_client_uv.cc
@@ -58,7 +58,7 @@ static void tcp_close_callback(uv_handle_t *handle) { gpr_free(handle); }
 static void uv_tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp,
                            grpc_error *error) {
   int done;
-  grpc_uv_tcp_connect *connect = acp;
+  grpc_uv_tcp_connect *connect = (grpc_uv_tcp_connect *)acp;
   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s",
@@ -77,7 +77,7 @@ static void uv_tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp,
 }
 
 static void uv_tc_on_connect(uv_connect_t *req, int status) {
-  grpc_uv_tcp_connect *connect = req->data;
+  grpc_uv_tcp_connect *connect = (grpc_uv_tcp_connect *)req->data;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_error *error = GRPC_ERROR_NONE;
   int done;
@@ -119,7 +119,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
                                     grpc_pollset_set *interested_parties,
                                     const grpc_channel_args *channel_args,
                                     const grpc_resolved_address *resolved_addr,
-                                    gpr_timespec deadline) {
+                                    grpc_millis deadline) {
   grpc_uv_tcp_connect *connect;
   grpc_resource_quota *resource_quota = grpc_resource_quota_create(NULL);
   (void)channel_args;
@@ -132,20 +132,20 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
       if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
         grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
         resource_quota = grpc_resource_quota_ref_internal(
-            channel_args->args[i].value.pointer.p);
+            (grpc_resource_quota *)channel_args->args[i].value.pointer.p);
       }
     }
   }
 
-  connect = gpr_zalloc(sizeof(grpc_uv_tcp_connect));
+  connect = (grpc_uv_tcp_connect *)gpr_zalloc(sizeof(grpc_uv_tcp_connect));
   connect->closure = closure;
   connect->endpoint = ep;
-  connect->tcp_handle = gpr_malloc(sizeof(uv_tcp_t));
+  connect->tcp_handle = (uv_tcp_t *)gpr_malloc(sizeof(uv_tcp_t));
   connect->addr_name = grpc_sockaddr_to_uri(resolved_addr);
   connect->resource_quota = resource_quota;
   uv_tcp_init(uv_default_loop(), connect->tcp_handle);
   connect->connect_req.data = connect;
-  connect->refs = 1;
+  connect->refs = 2;  // One for the connect operation, one for the timer.
 
   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting",
@@ -158,24 +158,24 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
                  uv_tc_on_connect);
   GRPC_CLOSURE_INIT(&connect->on_alarm, uv_tc_on_alarm, connect,
                     grpc_schedule_on_exec_ctx);
-  grpc_timer_init(exec_ctx, &connect->alarm,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  &connect->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_timer_init(exec_ctx, &connect->alarm, deadline, &connect->on_alarm);
 }
 
 // overridden by api_fuzzer.c
+extern "C" {
 void (*grpc_tcp_client_connect_impl)(
     grpc_exec_ctx *exec_ctx, grpc_closure *closure, grpc_endpoint **ep,
     grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
     const grpc_resolved_address *addr,
-    gpr_timespec deadline) = tcp_client_connect_impl;
+    grpc_millis deadline) = tcp_client_connect_impl;
+}
 
 void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                              grpc_endpoint **ep,
                              grpc_pollset_set *interested_parties,
                              const grpc_channel_args *channel_args,
                              const grpc_resolved_address *addr,
-                             gpr_timespec deadline) {
+                             grpc_millis deadline) {
   grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
                                channel_args, addr, deadline);
 }
diff --git a/src/core/lib/iomgr/tcp_client_windows.c b/src/core/lib/iomgr/tcp_client_windows.cc
index fc62105cc9..9adf7ee4e9 100644
--- a/src/core/lib/iomgr/tcp_client_windows.c
+++ b/src/core/lib/iomgr/tcp_client_windows.cc
@@ -18,6 +18,8 @@
 
 #include "src/core/lib/iomgr/port.h"
 
+#include <inttypes.h>
+
 #ifdef GRPC_WINSOCK_SOCKET
 
 #include "src/core/lib/iomgr/sockaddr_windows.h"
@@ -41,7 +43,6 @@ typedef struct {
   grpc_closure *on_done;
   gpr_mu mu;
   grpc_winsocket *socket;
-  gpr_timespec deadline;
   grpc_timer alarm;
   grpc_closure on_alarm;
   char *addr_name;
@@ -66,7 +67,7 @@ static void async_connect_unlock_and_cleanup(grpc_exec_ctx *exec_ctx,
 }
 
 static void on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
-  async_connect *ac = acp;
+  async_connect *ac = (async_connect *)acp;
   gpr_mu_lock(&ac->mu);
   grpc_winsocket *socket = ac->socket;
   ac->socket = NULL;
@@ -77,7 +78,7 @@ static void on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
 }
 
 static void on_connect(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
-  async_connect *ac = acp;
+  async_connect *ac = (async_connect *)acp;
   grpc_endpoint **ep = ac->endpoint;
   GPR_ASSERT(*ep == NULL);
   grpc_closure *on_done = ac->on_done;
@@ -124,7 +125,7 @@ static void on_connect(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
 static void tcp_client_connect_impl(
     grpc_exec_ctx *exec_ctx, grpc_closure *on_done, grpc_endpoint **endpoint,
     grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
-    const grpc_resolved_address *addr, gpr_timespec deadline) {
+    const grpc_resolved_address *addr, grpc_millis deadline) {
   SOCKET sock = INVALID_SOCKET;
   BOOL success;
   int status;
@@ -193,7 +194,7 @@ static void tcp_client_connect_impl(
     }
   }
 
-  ac = gpr_malloc(sizeof(async_connect));
+  ac = (async_connect *)gpr_malloc(sizeof(async_connect));
   ac->on_done = on_done;
   ac->socket = socket;
   gpr_mu_init(&ac->mu);
@@ -204,8 +205,7 @@ static void tcp_client_connect_impl(
   GRPC_CLOSURE_INIT(&ac->on_connect, on_connect, ac, grpc_schedule_on_exec_ctx);
 
   GRPC_CLOSURE_INIT(&ac->on_alarm, on_alarm, ac, grpc_schedule_on_exec_ctx);
-  grpc_timer_init(exec_ctx, &ac->alarm, deadline, &ac->on_alarm,
-                  gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_timer_init(exec_ctx, &ac->alarm, deadline, &ac->on_alarm);
   grpc_socket_notify_on_write(exec_ctx, socket, &ac->on_connect);
   return;
 
@@ -226,18 +226,20 @@ failure:
 }
 
 // overridden by api_fuzzer.c
+extern "C" {
 void (*grpc_tcp_client_connect_impl)(
     grpc_exec_ctx *exec_ctx, grpc_closure *closure, grpc_endpoint **ep,
     grpc_pollset_set *interested_parties, const grpc_channel_args *channel_args,
     const grpc_resolved_address *addr,
-    gpr_timespec deadline) = tcp_client_connect_impl;
+    grpc_millis deadline) = tcp_client_connect_impl;
+}
 
 void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                              grpc_endpoint **ep,
                              grpc_pollset_set *interested_parties,
                              const grpc_channel_args *channel_args,
                              const grpc_resolved_address *addr,
-                             gpr_timespec deadline) {
+                             grpc_millis deadline) {
   grpc_tcp_client_connect_impl(exec_ctx, closure, ep, interested_parties,
                                channel_args, addr, deadline);
 }
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.cc
index 7e271294fd..7fcaef7679 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.cc
@@ -135,13 +135,11 @@ static void run_poller(grpc_exec_ctx *exec_ctx, void *bp,
     gpr_log(GPR_DEBUG, "BACKUP_POLLER:%p run", p);
   }
   gpr_mu_lock(p->pollset_mu);
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
-  gpr_timespec deadline =
-      gpr_time_add(now, gpr_time_from_seconds(10, GPR_TIMESPAN));
+  grpc_millis deadline = grpc_exec_ctx_now(exec_ctx) + 13 * GPR_MS_PER_SEC;
   GRPC_STATS_INC_TCP_BACKUP_POLLER_POLLS(exec_ctx);
-  GRPC_LOG_IF_ERROR("backup_poller:pollset_work",
-                    grpc_pollset_work(exec_ctx, BACKUP_POLLER_POLLSET(p), NULL,
-                                      now, deadline));
+  GRPC_LOG_IF_ERROR(
+      "backup_poller:pollset_work",
+      grpc_pollset_work(exec_ctx, BACKUP_POLLER_POLLSET(p), NULL, deadline));
   gpr_mu_unlock(p->pollset_mu);
   /* last "uncovered" notification is the ref that keeps us polling, if we get
    * there try a cas to release it */
diff --git a/src/core/lib/iomgr/tcp_posix.h b/src/core/lib/iomgr/tcp_posix.h
index 6831a4a57f..dda78b2f8e 100644
--- a/src/core/lib/iomgr/tcp_posix.h
+++ b/src/core/lib/iomgr/tcp_posix.h
@@ -33,6 +33,10 @@
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_tracer_flag grpc_tcp_trace;
 
 /* Create a tcp endpoint given a file desciptor and a read slice size.
@@ -53,4 +57,8 @@ int grpc_tcp_fd(grpc_endpoint *ep);
 void grpc_tcp_destroy_and_release_fd(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
                                      int *fd, grpc_closure *done);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_server.h b/src/core/lib/iomgr/tcp_server.h
index 8a126b6dee..3f190ac285 100644
--- a/src/core/lib/iomgr/tcp_server.h
+++ b/src/core/lib/iomgr/tcp_server.h
@@ -25,6 +25,10 @@
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Forward decl of grpc_tcp_server */
 typedef struct grpc_tcp_server grpc_tcp_server;
 
@@ -98,4 +102,8 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s);
 void grpc_tcp_server_shutdown_listeners(grpc_exec_ctx *exec_ctx,
                                         grpc_tcp_server *s);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_server_posix.c b/src/core/lib/iomgr/tcp_server_posix.cc
index 06612d639c..06612d639c 100644
--- a/src/core/lib/iomgr/tcp_server_posix.c
+++ b/src/core/lib/iomgr/tcp_server_posix.cc
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix.h b/src/core/lib/iomgr/tcp_server_utils_posix.h
index 85dea515d9..4bb0660f09 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix.h
+++ b/src/core/lib/iomgr/tcp_server_utils_posix.h
@@ -24,6 +24,10 @@
 #include "src/core/lib/iomgr/socket_utils_posix.h"
 #include "src/core/lib/iomgr/tcp_server.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* one listening port */
 typedef struct grpc_tcp_listener {
   int fd;
@@ -117,4 +121,8 @@ grpc_error *grpc_tcp_server_prepare_socket(int fd,
 /* Ruturn true if the platform supports ifaddrs */
 bool grpc_tcp_server_have_ifaddrs(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_common.c b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
index a828bee074..a828bee074 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix_common.c
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.c b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc
index a243b69f35..a243b69f35 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.c
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_ifaddrs.cc
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.c b/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.cc
index 34eab20d6a..34eab20d6a 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.c
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_noifaddrs.cc
diff --git a/src/core/lib/iomgr/tcp_server_uv.c b/src/core/lib/iomgr/tcp_server_uv.cc
index 3b9332321f..348838c495 100644
--- a/src/core/lib/iomgr/tcp_server_uv.c
+++ b/src/core/lib/iomgr/tcp_server_uv.cc
@@ -77,14 +77,14 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
                                    grpc_closure *shutdown_complete,
                                    const grpc_channel_args *args,
                                    grpc_tcp_server **server) {
-  grpc_tcp_server *s = gpr_malloc(sizeof(grpc_tcp_server));
+  grpc_tcp_server *s = (grpc_tcp_server *)gpr_malloc(sizeof(grpc_tcp_server));
   s->resource_quota = grpc_resource_quota_create(NULL);
   for (size_t i = 0; i < (args == NULL ? 0 : args->num_args); i++) {
     if (0 == strcmp(GRPC_ARG_RESOURCE_QUOTA, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_POINTER) {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
-        s->resource_quota =
-            grpc_resource_quota_ref_internal(args->args[i].value.pointer.p);
+        s->resource_quota = grpc_resource_quota_ref_internal(
+            (grpc_resource_quota *)args->args[i].value.pointer.p);
       } else {
         grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
@@ -190,15 +190,16 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
 }
 
 static void finish_accept(grpc_exec_ctx *exec_ctx, grpc_tcp_listener *sp) {
-  grpc_tcp_server_acceptor *acceptor = gpr_malloc(sizeof(*acceptor));
-  uv_tcp_t *client;
+  grpc_tcp_server_acceptor *acceptor =
+      (grpc_tcp_server_acceptor *)gpr_malloc(sizeof(*acceptor));
+  uv_tcp_t *client = NULL;
   grpc_endpoint *ep = NULL;
   grpc_resolved_address peer_name;
   char *peer_name_string;
   int err;
   uv_tcp_t *server = sp->handle;
 
-  client = gpr_malloc(sizeof(uv_tcp_t));
+  client = (uv_tcp_t *)gpr_malloc(sizeof(uv_tcp_t));
   uv_tcp_init(uv_default_loop(), client);
   // UV documentation says this is guaranteed to succeed
   uv_accept((uv_stream_t *)server, (uv_stream_t *)client);
@@ -303,7 +304,7 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, uv_tcp_t *handle,
 
   GPR_ASSERT(port >= 0);
   GPR_ASSERT(!s->on_accept_cb && "must add ports before starting server");
-  sp = gpr_zalloc(sizeof(grpc_tcp_listener));
+  sp = (grpc_tcp_listener *)gpr_zalloc(sizeof(grpc_tcp_listener));
   sp->next = NULL;
   if (s->head == NULL) {
     s->head = sp;
@@ -355,7 +356,8 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
                                   (int *)&sockname_temp.len)) {
         *port = grpc_sockaddr_get_port(&sockname_temp);
         if (*port > 0) {
-          allocated_addr = gpr_malloc(sizeof(grpc_resolved_address));
+          allocated_addr = (grpc_resolved_address *)gpr_malloc(
+              sizeof(grpc_resolved_address));
           memcpy(allocated_addr, addr, sizeof(grpc_resolved_address));
           grpc_sockaddr_set_port(allocated_addr, *port);
           addr = allocated_addr;
@@ -376,7 +378,7 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
     addr = &wildcard;
   }
 
-  handle = gpr_malloc(sizeof(uv_tcp_t));
+  handle = (uv_tcp_t *)gpr_malloc(sizeof(uv_tcp_t));
 
   family = grpc_sockaddr_get_family(addr);
   status = uv_tcp_init_ex(uv_default_loop(), handle, (unsigned int)family);
diff --git a/src/core/lib/iomgr/tcp_server_windows.c b/src/core/lib/iomgr/tcp_server_windows.cc
index 0162afc1ad..f198aaaa5b 100644
--- a/src/core/lib/iomgr/tcp_server_windows.c
+++ b/src/core/lib/iomgr/tcp_server_windows.cc
@@ -22,6 +22,7 @@
 
 #include "src/core/lib/iomgr/sockaddr.h"
 
+#include <inttypes.h>
 #include <io.h>
 
 #include <grpc/support/alloc.h>
@@ -97,7 +98,7 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
                                    grpc_closure *shutdown_complete,
                                    const grpc_channel_args *args,
                                    grpc_tcp_server **server) {
-  grpc_tcp_server *s = gpr_malloc(sizeof(grpc_tcp_server));
+  grpc_tcp_server *s = (grpc_tcp_server *)gpr_malloc(sizeof(grpc_tcp_server));
   s->channel_args = grpc_channel_args_copy(args);
   gpr_ref_init(&s->refs, 1);
   gpr_mu_init(&s->mu);
@@ -115,7 +116,7 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
 
 static void destroy_server(grpc_exec_ctx *exec_ctx, void *arg,
                            grpc_error *error) {
-  grpc_tcp_server *s = arg;
+  grpc_tcp_server *s = (grpc_tcp_server *)arg;
 
   /* Now that the accepts have been aborted, we can destroy the sockets.
      The IOCP won't get notified on these, so we can flag them as already
@@ -188,6 +189,7 @@ static grpc_error *prepare_socket(SOCKET sock,
                                   int *port) {
   grpc_resolved_address sockname_temp;
   grpc_error *error = GRPC_ERROR_NONE;
+  int sockname_temp_len;
 
   error = grpc_tcp_prepare_socket(sock);
   if (error != GRPC_ERROR_NONE) {
@@ -205,7 +207,7 @@ static grpc_error *prepare_socket(SOCKET sock,
     goto failure;
   }
 
-  int sockname_temp_len = sizeof(struct sockaddr_storage);
+  sockname_temp_len = sizeof(struct sockaddr_storage);
   if (getsockname(sock, (struct sockaddr *)sockname_temp.addr,
                   &sockname_temp_len) == SOCKET_ERROR) {
     error = GRPC_WSA_ERROR(WSAGetLastError(), "getsockname");
@@ -294,7 +296,7 @@ failure:
 
 /* Event manager callback when reads are ready. */
 static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  grpc_tcp_listener *sp = arg;
+  grpc_tcp_listener *sp = (grpc_tcp_listener *)arg;
   SOCKET sock = sp->new_socket;
   grpc_winsocket_callback_info *info = &sp->socket->read_info;
   grpc_endpoint *ep = NULL;
@@ -368,7 +370,8 @@ static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
      managed to accept a connection, and created an endpoint. */
   if (ep) {
     // Create acceptor.
-    grpc_tcp_server_acceptor *acceptor = gpr_malloc(sizeof(*acceptor));
+    grpc_tcp_server_acceptor *acceptor =
+        (grpc_tcp_server_acceptor *)gpr_malloc(sizeof(*acceptor));
     acceptor->from_server = sp->server;
     acceptor->port_index = sp->port_index;
     acceptor->fd_index = 0;
@@ -421,7 +424,7 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, SOCKET sock,
   GPR_ASSERT(port >= 0);
   gpr_mu_lock(&s->mu);
   GPR_ASSERT(!s->on_accept_cb && "must add ports before starting server");
-  sp = gpr_malloc(sizeof(grpc_tcp_listener));
+  sp = (grpc_tcp_listener *)gpr_malloc(sizeof(grpc_tcp_listener));
   sp->next = NULL;
   if (s->head == NULL) {
     s->head = sp;
@@ -472,7 +475,8 @@ grpc_error *grpc_tcp_server_add_port(grpc_tcp_server *s,
         sockname_temp.len = (size_t)sockname_temp_len;
         *port = grpc_sockaddr_get_port(&sockname_temp);
         if (*port > 0) {
-          allocated_addr = gpr_malloc(sizeof(grpc_resolved_address));
+          allocated_addr = (grpc_resolved_address *)gpr_malloc(
+              sizeof(grpc_resolved_address));
           memcpy(allocated_addr, addr, sizeof(grpc_resolved_address));
           grpc_sockaddr_set_port(allocated_addr, *port);
           addr = allocated_addr;
diff --git a/src/core/lib/iomgr/tcp_uv.c b/src/core/lib/iomgr/tcp_uv.cc
index a05c19b4ac..e311964dbc 100644
--- a/src/core/lib/iomgr/tcp_uv.c
+++ b/src/core/lib/iomgr/tcp_uv.cc
@@ -114,7 +114,7 @@ static void tcp_ref(grpc_tcp *tcp) { gpr_ref(&tcp->refcount); }
 
 static void uv_close_callback(uv_handle_t *handle) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_tcp *tcp = handle->data;
+  grpc_tcp *tcp = (grpc_tcp *)handle->data;
   TCP_UNREF(&exec_ctx, tcp, "destroy");
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -128,7 +128,7 @@ static grpc_slice alloc_read_slice(grpc_exec_ctx *exec_ctx,
 static void alloc_uv_buf(uv_handle_t *handle, size_t suggested_size,
                          uv_buf_t *buf) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_tcp *tcp = handle->data;
+  grpc_tcp *tcp = (grpc_tcp *)handle->data;
   (void)suggested_size;
   buf->base = (char *)GRPC_SLICE_START_PTR(tcp->read_slice);
   buf->len = GRPC_SLICE_LENGTH(tcp->read_slice);
@@ -140,7 +140,7 @@ static void read_callback(uv_stream_t *stream, ssize_t nread,
   grpc_slice sub;
   grpc_error *error;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_tcp *tcp = stream->data;
+  grpc_tcp *tcp = (grpc_tcp *)stream->data;
   grpc_closure *cb = tcp->read_cb;
   if (nread == 0) {
     // Nothing happened. Wait for the next callback
@@ -207,7 +207,7 @@ static void uv_endpoint_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 }
 
 static void write_callback(uv_write_t *req, int status) {
-  grpc_tcp *tcp = req->data;
+  grpc_tcp *tcp = (grpc_tcp *)req->data;
   grpc_error *error;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_closure *cb = tcp->write_cb;
@@ -269,7 +269,7 @@ static void uv_endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   tcp->write_cb = cb;
   buffer_count = (unsigned int)tcp->write_slices->count;
-  buffers = gpr_malloc(sizeof(uv_buf_t) * buffer_count);
+  buffers = (uv_buf_t *)gpr_malloc(sizeof(uv_buf_t) * buffer_count);
   grpc_resource_user_alloc(exec_ctx, tcp->resource_user,
                            sizeof(uv_buf_t) * buffer_count, NULL);
   for (i = 0; i < buffer_count; i++) {
diff --git a/src/core/lib/iomgr/tcp_uv.h b/src/core/lib/iomgr/tcp_uv.h
index 0e67481d35..ba7db8a0f7 100644
--- a/src/core/lib/iomgr/tcp_uv.h
+++ b/src/core/lib/iomgr/tcp_uv.h
@@ -38,8 +38,16 @@ extern grpc_tracer_flag grpc_tcp_trace;
 
 #define GRPC_TCP_DEFAULT_READ_SLICE_SIZE 8192
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_endpoint *grpc_tcp_create(uv_tcp_t *handle,
                                grpc_resource_quota *resource_quota,
                                char *peer_string);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TCP_UV_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TCP_UV_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/tcp_windows.c b/src/core/lib/iomgr/tcp_windows.cc
index 2cbb97403b..dc84e564a9 100644
--- a/src/core/lib/iomgr/tcp_windows.c
+++ b/src/core/lib/iomgr/tcp_windows.cc
@@ -37,6 +37,7 @@
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/socket_windows.h"
 #include "src/core/lib/iomgr/tcp_client.h"
+#include "src/core/lib/iomgr/tcp_windows.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/slice/slice_internal.h"
 
@@ -158,7 +159,7 @@ static void tcp_ref(grpc_tcp *tcp) { gpr_ref(&tcp->refcount); }
 
 /* Asynchronous callback from the IOCP, or the background thread. */
 static void on_read(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
-  grpc_tcp *tcp = tcpp;
+  grpc_tcp *tcp = (grpc_tcp *)tcpp;
   grpc_closure *cb = tcp->read_cb;
   grpc_winsocket *socket = tcp->socket;
   grpc_slice sub;
@@ -418,14 +419,14 @@ static grpc_endpoint_vtable vtable = {
 
 grpc_endpoint *grpc_tcp_create(grpc_exec_ctx *exec_ctx, grpc_winsocket *socket,
                                grpc_channel_args *channel_args,
-                               char *peer_string) {
+                               const char *peer_string) {
   grpc_resource_quota *resource_quota = grpc_resource_quota_create(NULL);
   if (channel_args != NULL) {
     for (size_t i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
         grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
         resource_quota = grpc_resource_quota_ref_internal(
-            channel_args->args[i].value.pointer.p);
+            (grpc_resource_quota *)channel_args->args[i].value.pointer.p);
       }
     }
   }
diff --git a/src/core/lib/iomgr/tcp_windows.h b/src/core/lib/iomgr/tcp_windows.h
index 864184ce84..f3697f707c 100644
--- a/src/core/lib/iomgr/tcp_windows.h
+++ b/src/core/lib/iomgr/tcp_windows.h
@@ -32,13 +32,21 @@
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/socket_windows.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Create a tcp endpoint given a winsock handle.
  * Takes ownership of the handle.
  */
 grpc_endpoint *grpc_tcp_create(grpc_exec_ctx *exec_ctx, grpc_winsocket *socket,
                                grpc_channel_args *channel_args,
-                               char *peer_string);
+                               const char *peer_string);
 
 grpc_error *grpc_tcp_prepare_socket(SOCKET sock);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_TCP_WINDOWS_H */
diff --git a/src/core/lib/iomgr/time_averaged_stats.c b/src/core/lib/iomgr/time_averaged_stats.cc
index 3bddec04dd..3bddec04dd 100644
--- a/src/core/lib/iomgr/time_averaged_stats.c
+++ b/src/core/lib/iomgr/time_averaged_stats.cc
diff --git a/src/core/lib/iomgr/time_averaged_stats.h b/src/core/lib/iomgr/time_averaged_stats.h
index 8745f7fa13..e255b58fee 100644
--- a/src/core/lib/iomgr/time_averaged_stats.h
+++ b/src/core/lib/iomgr/time_averaged_stats.h
@@ -19,6 +19,10 @@
 #ifndef GRPC_CORE_LIB_IOMGR_TIME_AVERAGED_STATS_H
 #define GRPC_CORE_LIB_IOMGR_TIME_AVERAGED_STATS_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* This tracks a time-decaying weighted average.  It works by collecting
    batches of samples and then mixing their average into a time-decaying
    weighted mean.  It is designed for batch operations where we do many adds
@@ -70,4 +74,8 @@ void grpc_time_averaged_stats_add_sample(grpc_time_averaged_stats* stats,
    value. */
 double grpc_time_averaged_stats_update_average(grpc_time_averaged_stats* stats);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TIME_AVERAGED_STATS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TIME_AVERAGED_STATS_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/timer.h b/src/core/lib/iomgr/timer.h
index ac392f87fe..419e834cf1 100644
--- a/src/core/lib/iomgr/timer.h
+++ b/src/core/lib/iomgr/timer.h
@@ -32,6 +32,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/iomgr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_timer grpc_timer;
 
 /* Initialize *timer. When expired or canceled, closure will be called with
@@ -41,8 +45,7 @@ typedef struct grpc_timer grpc_timer;
    application callback is also responsible for maintaining information about
    when to free up any user-level state. */
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_closure *closure,
-                     gpr_timespec now);
+                     grpc_millis deadline, grpc_closure *closure);
 
 /* Initialize *timer without setting it. This can later be passed through
    the regular init or cancel */
@@ -92,8 +95,8 @@ typedef enum {
    with high probability at least one thread in the system will see an update
    at any time slice. */
 grpc_timer_check_result grpc_timer_check(grpc_exec_ctx *exec_ctx,
-                                         gpr_timespec now, gpr_timespec *next);
-void grpc_timer_list_init(gpr_timespec now);
+                                         grpc_millis *next);
+void grpc_timer_list_init(grpc_exec_ctx *exec_ctx);
 void grpc_timer_list_shutdown(grpc_exec_ctx *exec_ctx);
 
 /* Consume a kick issued by grpc_kick_poller */
@@ -103,4 +106,8 @@ void grpc_timer_consume_kick(void);
 
 void grpc_kick_poller(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_TIMER_H */
diff --git a/src/core/lib/iomgr/timer_generic.c b/src/core/lib/iomgr/timer_generic.cc
index e9a7236c8c..b8e895de6f 100644
--- a/src/core/lib/iomgr/timer_generic.c
+++ b/src/core/lib/iomgr/timer_generic.cc
@@ -18,6 +18,8 @@
 
 #include "src/core/lib/iomgr/port.h"
 
+#include <inttypes.h>
+
 #ifdef GRPC_TIMER_USE_GENERIC
 
 #include "src/core/lib/iomgr/timer.h"
@@ -41,9 +43,11 @@
 #define MIN_QUEUE_WINDOW_DURATION 0.01
 #define MAX_QUEUE_WINDOW_DURATION 1
 
+extern "C" {
 grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false, "timer");
 grpc_tracer_flag grpc_timer_check_trace =
     GRPC_TRACER_INITIALIZER(false, "timer_check");
+}
 
 /* A "timer shard". Contains a 'heap' and a 'list' of timers. All timers with
  * deadlines earlier than 'queue_deadline" cap are maintained in the heap and
@@ -79,6 +83,125 @@ static timer_shard g_shards[NUM_SHARDS];
  * Access to this is protected by g_shared_mutables.mu */
 static timer_shard *g_shard_queue[NUM_SHARDS];
 
+#ifndef NDEBUG
+
+/* == Hash table for duplicate timer detection == */
+
+#define NUM_HASH_BUCKETS 1009 /* Prime number close to 1000 */
+
+static gpr_mu g_hash_mu[NUM_HASH_BUCKETS]; /* One mutex per bucket */
+static grpc_timer *g_timer_ht[NUM_HASH_BUCKETS] = {NULL};
+
+static void init_timer_ht() {
+  for (int i = 0; i < NUM_HASH_BUCKETS; i++) {
+    gpr_mu_init(&g_hash_mu[i]);
+  }
+}
+
+static bool is_in_ht(grpc_timer *t) {
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  grpc_timer *p = g_timer_ht[i];
+  while (p != NULL && p != t) {
+    p = p->hash_table_next;
+  }
+  gpr_mu_unlock(&g_hash_mu[i]);
+
+  return (p == t);
+}
+
+static void add_to_ht(grpc_timer *t) {
+  GPR_ASSERT(!t->hash_table_next);
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  grpc_timer *p = g_timer_ht[i];
+  while (p != NULL && p != t) {
+    p = p->hash_table_next;
+  }
+
+  if (p == t) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** Duplicate timer (%p) being added. Closure: (%p), created at: "
+            "(%s:%d), scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+
+  /* Timer not present in the bucket. Insert at head of the list */
+  t->hash_table_next = g_timer_ht[i];
+  g_timer_ht[i] = t;
+  gpr_mu_unlock(&g_hash_mu[i]);
+}
+
+static void remove_from_ht(grpc_timer *t) {
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+  bool removed = false;
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  if (g_timer_ht[i] == t) {
+    g_timer_ht[i] = g_timer_ht[i]->hash_table_next;
+    removed = true;
+  } else if (g_timer_ht[i] != NULL) {
+    grpc_timer *p = g_timer_ht[i];
+    while (p->hash_table_next != NULL && p->hash_table_next != t) {
+      p = p->hash_table_next;
+    }
+
+    if (p->hash_table_next == t) {
+      p->hash_table_next = t->hash_table_next;
+      removed = true;
+    }
+  }
+  gpr_mu_unlock(&g_hash_mu[i]);
+
+  if (!removed) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** Removing timer (%p) that is not added to hash table. Closure "
+            "(%p), created at: (%s:%d), scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+
+  t->hash_table_next = NULL;
+}
+
+/* If a timer is added to a timer shard (either heap or a list), it cannot
+ * be pending. A timer is added to hash table only-if it is added to the
+ * timer shard.
+ * Therefore, if timer->pending is false, it cannot be in hash table */
+static void validate_non_pending_timer(grpc_timer *t) {
+  if (!t->pending && is_in_ht(t)) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** gpr_timer_cancel() called on a non-pending timer (%p) which "
+            "is in the hash table. Closure: (%p), created at: (%s:%d), "
+            "scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+}
+
+#define INIT_TIMER_HASH_TABLE() init_timer_ht()
+#define ADD_TO_HASH_TABLE(t) add_to_ht((t))
+#define REMOVE_FROM_HASH_TABLE(t) remove_from_ht((t))
+#define VALIDATE_NON_PENDING_TIMER(t) validate_non_pending_timer((t))
+
+#else
+
+#define INIT_TIMER_HASH_TABLE()
+#define ADD_TO_HASH_TABLE(t)
+#define REMOVE_FROM_HASH_TABLE(t)
+#define VALIDATE_NON_PENDING_TIMER(t)
+
+#endif
+
 /* Thread local variable that stores the deadline of the next timer the thread
  * has last-seen. This is an optimization to prevent the thread from checking
  * shared_mutables.min_timer (which requires acquiring shared_mutables.mu lock,
@@ -97,9 +220,6 @@ struct shared_mutables {
 
 static struct shared_mutables g_shared_mutables;
 
-static gpr_clock_type g_clock_type;
-static gpr_timespec g_start_time;
-
 static gpr_atm saturating_add(gpr_atm a, gpr_atm b) {
   if (a > GPR_ATM_MAX - b) {
     return GPR_ATM_MAX;
@@ -112,52 +232,19 @@ static grpc_timer_check_result run_some_expired_timers(grpc_exec_ctx *exec_ctx,
                                                        gpr_atm *next,
                                                        grpc_error *error);
 
-static gpr_timespec dbl_to_ts(double d) {
-  gpr_timespec ts;
-  ts.tv_sec = (int64_t)d;
-  ts.tv_nsec = (int32_t)(1e9 * (d - (double)ts.tv_sec));
-  ts.clock_type = GPR_TIMESPAN;
-  return ts;
-}
-
-static gpr_atm timespec_to_atm_round_up(gpr_timespec ts) {
-  ts = gpr_time_sub(ts, g_start_time);
-  double x = GPR_MS_PER_SEC * (double)ts.tv_sec +
-             (double)ts.tv_nsec / GPR_NS_PER_MS +
-             (double)(GPR_NS_PER_SEC - 1) / (double)GPR_NS_PER_SEC;
-  if (x < 0) return 0;
-  if (x > GPR_ATM_MAX) return GPR_ATM_MAX;
-  return (gpr_atm)x;
-}
-
-static gpr_atm timespec_to_atm_round_down(gpr_timespec ts) {
-  ts = gpr_time_sub(ts, g_start_time);
-  double x =
-      GPR_MS_PER_SEC * (double)ts.tv_sec + (double)ts.tv_nsec / GPR_NS_PER_MS;
-  if (x < 0) return 0;
-  if (x > GPR_ATM_MAX) return GPR_ATM_MAX;
-  return (gpr_atm)x;
-}
-
-static gpr_timespec atm_to_timespec(gpr_atm x) {
-  return gpr_time_add(g_start_time, dbl_to_ts((double)x / 1000.0));
-}
-
 static gpr_atm compute_min_deadline(timer_shard *shard) {
   return grpc_timer_heap_is_empty(&shard->heap)
              ? saturating_add(shard->queue_deadline_cap, 1)
              : grpc_timer_heap_top(&shard->heap)->deadline;
 }
 
-void grpc_timer_list_init(gpr_timespec now) {
+void grpc_timer_list_init(grpc_exec_ctx *exec_ctx) {
   uint32_t i;
 
   g_shared_mutables.initialized = true;
   g_shared_mutables.checker_mu = GPR_SPINLOCK_INITIALIZER;
   gpr_mu_init(&g_shared_mutables.mu);
-  g_clock_type = now.clock_type;
-  g_start_time = now;
-  g_shared_mutables.min_timer = timespec_to_atm_round_down(now);
+  g_shared_mutables.min_timer = grpc_exec_ctx_now(exec_ctx);
   gpr_tls_init(&g_last_seen_min_timer);
   gpr_tls_set(&g_last_seen_min_timer, 0);
   grpc_register_tracer(&grpc_timer_trace);
@@ -175,6 +262,8 @@ void grpc_timer_list_init(gpr_timespec now) {
     shard->min_deadline = compute_min_deadline(shard);
     g_shard_queue[i] = shard;
   }
+
+  INIT_TIMER_HASH_TABLE();
 }
 
 void grpc_timer_list_shutdown(grpc_exec_ctx *exec_ctx) {
@@ -192,10 +281,6 @@ void grpc_timer_list_shutdown(grpc_exec_ctx *exec_ctx) {
   g_shared_mutables.initialized = false;
 }
 
-static double ts_to_dbl(gpr_timespec ts) {
-  return (double)ts.tv_sec + 1e-9 * ts.tv_nsec;
-}
-
 /* returns true if the first element in the list */
 static void list_join(grpc_timer *head, grpc_timer *timer) {
   timer->next = head;
@@ -236,20 +321,20 @@ static void note_deadline_change(timer_shard *shard) {
 void grpc_timer_init_unset(grpc_timer *timer) { timer->pending = false; }
 
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_closure *closure,
-                     gpr_timespec now) {
+                     grpc_millis deadline, grpc_closure *closure) {
   int is_first_timer = 0;
   timer_shard *shard = &g_shards[GPR_HASH_POINTER(timer, NUM_SHARDS)];
-  GPR_ASSERT(deadline.clock_type == g_clock_type);
-  GPR_ASSERT(now.clock_type == g_clock_type);
   timer->closure = closure;
-  gpr_atm deadline_atm = timer->deadline = timespec_to_atm_round_up(deadline);
+  timer->deadline = deadline;
+
+#ifndef NDEBUG
+  timer->hash_table_next = NULL;
+#endif
 
   if (GRPC_TRACER_ON(grpc_timer_trace)) {
-    gpr_log(GPR_DEBUG, "TIMER %p: SET %" PRId64 ".%09d [%" PRIdPTR
-                       "] now %" PRId64 ".%09d [%" PRIdPTR "] call %p[%p]",
-            timer, deadline.tv_sec, deadline.tv_nsec, deadline_atm, now.tv_sec,
-            now.tv_nsec, timespec_to_atm_round_down(now), closure, closure->cb);
+    gpr_log(GPR_DEBUG,
+            "TIMER %p: SET %" PRIdPTR " now %" PRIdPTR " call %p[%p]", timer,
+            deadline, grpc_exec_ctx_now(exec_ctx), closure, closure->cb);
   }
 
   if (!g_shared_mutables.initialized) {
@@ -262,7 +347,8 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
 
   gpr_mu_lock(&shard->mu);
   timer->pending = true;
-  if (gpr_time_cmp(deadline, now) <= 0) {
+  grpc_millis now = grpc_exec_ctx_now(exec_ctx);
+  if (deadline <= now) {
     timer->pending = false;
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_NONE);
     gpr_mu_unlock(&shard->mu);
@@ -271,8 +357,11 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
   }
 
   grpc_time_averaged_stats_add_sample(&shard->stats,
-                                      ts_to_dbl(gpr_time_sub(deadline, now)));
-  if (deadline_atm < shard->queue_deadline_cap) {
+                                      (double)(deadline - now) / 1000.0);
+
+  ADD_TO_HASH_TABLE(timer);
+
+  if (deadline < shard->queue_deadline_cap) {
     is_first_timer = grpc_timer_heap_add(&shard->heap, timer);
   } else {
     timer->heap_index = INVALID_HEAP_INDEX;
@@ -303,12 +392,12 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
       gpr_log(GPR_DEBUG, "  .. old shard min_deadline=%" PRIdPTR,
               shard->min_deadline);
     }
-    if (deadline_atm < shard->min_deadline) {
+    if (deadline < shard->min_deadline) {
       gpr_atm old_min_deadline = g_shard_queue[0]->min_deadline;
-      shard->min_deadline = deadline_atm;
+      shard->min_deadline = deadline;
       note_deadline_change(shard);
-      if (shard->shard_queue_index == 0 && deadline_atm < old_min_deadline) {
-        gpr_atm_no_barrier_store(&g_shared_mutables.min_timer, deadline_atm);
+      if (shard->shard_queue_index == 0 && deadline < old_min_deadline) {
+        gpr_atm_no_barrier_store(&g_shared_mutables.min_timer, deadline);
         grpc_kick_poller();
       }
     }
@@ -333,7 +422,10 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
     gpr_log(GPR_DEBUG, "TIMER %p: CANCEL pending=%s", timer,
             timer->pending ? "true" : "false");
   }
+
   if (timer->pending) {
+    REMOVE_FROM_HASH_TABLE(timer);
+
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_CANCELLED);
     timer->pending = false;
     if (timer->heap_index == INVALID_HEAP_INDEX) {
@@ -341,6 +433,8 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
     } else {
       grpc_timer_heap_remove(&shard->heap, timer);
     }
+  } else {
+    VALIDATE_NON_PENDING_TIMER(timer);
   }
   gpr_mu_unlock(&shard->mu);
 }
@@ -407,8 +501,9 @@ static grpc_timer *pop_one(timer_shard *shard, gpr_atm now) {
     }
     if (timer->deadline > now) return NULL;
     if (GRPC_TRACER_ON(grpc_timer_trace)) {
-      gpr_log(GPR_DEBUG, "TIMER %p: FIRE %" PRIdPTR "ms late", timer,
-              now - timer->deadline);
+      gpr_log(GPR_DEBUG, "TIMER %p: FIRE %" PRIdPTR "ms late via %s scheduler",
+              timer, now - timer->deadline,
+              timer->closure->scheduler->vtable->name);
     }
     timer->pending = false;
     grpc_timer_heap_pop(&shard->heap);
@@ -424,11 +519,16 @@ static size_t pop_timers(grpc_exec_ctx *exec_ctx, timer_shard *shard,
   grpc_timer *timer;
   gpr_mu_lock(&shard->mu);
   while ((timer = pop_one(shard, now))) {
+    REMOVE_FROM_HASH_TABLE(timer);
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_REF(error));
     n++;
   }
   *new_min_deadline = compute_min_deadline(shard);
   gpr_mu_unlock(&shard->mu);
+  if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
+    gpr_log(GPR_DEBUG, "  .. shard[%d] popped %" PRIdPTR,
+            (int)(shard - g_shards), n);
+  }
   return n;
 }
 
@@ -501,29 +601,27 @@ static grpc_timer_check_result run_some_expired_timers(grpc_exec_ctx *exec_ctx,
 }
 
 grpc_timer_check_result grpc_timer_check(grpc_exec_ctx *exec_ctx,
-                                         gpr_timespec now, gpr_timespec *next) {
+                                         grpc_millis *next) {
   // prelude
-  GPR_ASSERT(now.clock_type == g_clock_type);
-  gpr_atm now_atm = timespec_to_atm_round_down(now);
+  grpc_millis now = grpc_exec_ctx_now(exec_ctx);
 
   /* fetch from a thread-local first: this avoids contention on a globally
      mutable cacheline in the common case */
-  gpr_atm min_timer = gpr_tls_get(&g_last_seen_min_timer);
-  if (now_atm < min_timer) {
+  grpc_millis min_timer = gpr_tls_get(&g_last_seen_min_timer);
+  if (now < min_timer) {
     if (next != NULL) {
-      *next =
-          atm_to_timespec(GPR_MIN(timespec_to_atm_round_up(*next), min_timer));
+      *next = GPR_MIN(*next, min_timer);
     }
     if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
       gpr_log(GPR_DEBUG,
-              "TIMER CHECK SKIP: now_atm=%" PRIdPTR " min_timer=%" PRIdPTR,
-              now_atm, min_timer);
+              "TIMER CHECK SKIP: now=%" PRIdPTR " min_timer=%" PRIdPTR, now,
+              min_timer);
     }
     return GRPC_TIMERS_CHECKED_AND_EMPTY;
   }
 
   grpc_error *shutdown_error =
-      gpr_time_cmp(now, gpr_inf_future(now.clock_type)) != 0
+      now != GRPC_MILLIS_INF_FUTURE
           ? GRPC_ERROR_NONE
           : GRPC_ERROR_CREATE_FROM_STATIC_STRING("Shutting down timer system");
 
@@ -533,34 +631,24 @@ grpc_timer_check_result grpc_timer_check(grpc_exec_ctx *exec_ctx,
     if (next == NULL) {
       next_str = gpr_strdup("NULL");
     } else {
-      gpr_asprintf(&next_str, "%" PRId64 ".%09d [%" PRIdPTR "]", next->tv_sec,
-                   next->tv_nsec, timespec_to_atm_round_down(*next));
+      gpr_asprintf(&next_str, "%" PRIdPTR, *next);
     }
-    gpr_log(GPR_DEBUG, "TIMER CHECK BEGIN: now=%" PRId64 ".%09d [%" PRIdPTR
-                       "] next=%s tls_min=%" PRIdPTR " glob_min=%" PRIdPTR,
-            now.tv_sec, now.tv_nsec, now_atm, next_str,
-            gpr_tls_get(&g_last_seen_min_timer),
+    gpr_log(GPR_DEBUG, "TIMER CHECK BEGIN: now=%" PRIdPTR
+                       " next=%s tls_min=%" PRIdPTR " glob_min=%" PRIdPTR,
+            now, next_str, gpr_tls_get(&g_last_seen_min_timer),
             gpr_atm_no_barrier_load(&g_shared_mutables.min_timer));
     gpr_free(next_str);
   }
   // actual code
-  grpc_timer_check_result r;
-  gpr_atm next_atm;
-  if (next == NULL) {
-    r = run_some_expired_timers(exec_ctx, now_atm, NULL, shutdown_error);
-  } else {
-    next_atm = timespec_to_atm_round_down(*next);
-    r = run_some_expired_timers(exec_ctx, now_atm, &next_atm, shutdown_error);
-    *next = atm_to_timespec(next_atm);
-  }
+  grpc_timer_check_result r =
+      run_some_expired_timers(exec_ctx, now, next, shutdown_error);
   // tracing
   if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
     char *next_str;
     if (next == NULL) {
       next_str = gpr_strdup("NULL");
     } else {
-      gpr_asprintf(&next_str, "%" PRId64 ".%09d [%" PRIdPTR "]", next->tv_sec,
-                   next->tv_nsec, next_atm);
+      gpr_asprintf(&next_str, "%" PRIdPTR, *next);
     }
     gpr_log(GPR_DEBUG, "TIMER CHECK END: r=%d; next=%s", r, next_str);
     gpr_free(next_str);
diff --git a/src/core/lib/iomgr/timer_generic.h b/src/core/lib/iomgr/timer_generic.h
index 72a4ac1f10..f0597f6ea0 100644
--- a/src/core/lib/iomgr/timer_generic.h
+++ b/src/core/lib/iomgr/timer_generic.h
@@ -29,6 +29,9 @@ struct grpc_timer {
   struct grpc_timer *next;
   struct grpc_timer *prev;
   grpc_closure *closure;
+#ifndef NDEBUG
+  struct grpc_timer *hash_table_next;
+#endif
 };
 
 #endif /* GRPC_CORE_LIB_IOMGR_TIMER_GENERIC_H */
diff --git a/src/core/lib/iomgr/timer_heap.c b/src/core/lib/iomgr/timer_heap.cc
index 2648d5da5d..2648d5da5d 100644
--- a/src/core/lib/iomgr/timer_heap.c
+++ b/src/core/lib/iomgr/timer_heap.cc
diff --git a/src/core/lib/iomgr/timer_heap.h b/src/core/lib/iomgr/timer_heap.h
index 0d64199ab9..f15e8a3abb 100644
--- a/src/core/lib/iomgr/timer_heap.h
+++ b/src/core/lib/iomgr/timer_heap.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/iomgr/timer.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
   grpc_timer **timers;
   uint32_t timer_count;
@@ -39,4 +43,8 @@ void grpc_timer_heap_pop(grpc_timer_heap *heap);
 
 int grpc_timer_heap_is_empty(grpc_timer_heap *heap);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TIMER_HEAP_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TIMER_HEAP_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/timer_manager.c b/src/core/lib/iomgr/timer_manager.cc
index 04ca44563d..1248f82189 100644
--- a/src/core/lib/iomgr/timer_manager.c
+++ b/src/core/lib/iomgr/timer_manager.cc
@@ -20,8 +20,11 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/port_platform.h>
 #include <grpc/support/thd.h>
 
+#include <inttypes.h>
+
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/timer.h"
 
@@ -30,7 +33,7 @@ typedef struct completed_thread {
   struct completed_thread *next;
 } completed_thread;
 
-extern grpc_tracer_flag grpc_timer_check_trace;
+extern "C" grpc_tracer_flag grpc_timer_check_trace;
 
 // global mutex
 static gpr_mu g_mu;
@@ -52,7 +55,7 @@ static bool g_kicked;
 static bool g_has_timed_waiter;
 // the deadline of the current timed waiter thread (only relevant if
 // g_has_timed_waiter is true)
-static gpr_timespec g_timed_waiter_deadline;
+static grpc_millis g_timed_waiter_deadline;
 // generation counter to track which thread is waiting for the next timer
 static uint64_t g_timed_waiter_generation;
 
@@ -96,9 +99,8 @@ static void start_timer_thread_and_unlock(void) {
 
 void grpc_timer_manager_tick() {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  gpr_timespec next = gpr_inf_future(GPR_CLOCK_MONOTONIC);
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
-  grpc_timer_check(&exec_ctx, now, &next);
+  grpc_millis next = GRPC_MILLIS_INF_FUTURE;
+  grpc_timer_check(&exec_ctx, &next);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -121,6 +123,9 @@ static void run_some_timers(grpc_exec_ctx *exec_ctx) {
     gpr_mu_unlock(&g_mu);
   }
   // without our lock, flush the exec_ctx
+  if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
+    gpr_log(GPR_DEBUG, "flush exec_ctx");
+  }
   grpc_exec_ctx_flush(exec_ctx);
   gpr_mu_lock(&g_mu);
   // garbage collect any threads hanging out that are dead
@@ -133,8 +138,7 @@ static void run_some_timers(grpc_exec_ctx *exec_ctx) {
 // wait until 'next' (or forever if there is already a timed waiter in the pool)
 // returns true if the thread should continue executing (false if it should
 // shutdown)
-static bool wait_until(gpr_timespec next) {
-  const gpr_timespec inf_future = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+static bool wait_until(grpc_exec_ctx *exec_ctx, grpc_millis next) {
   gpr_mu_lock(&g_mu);
   // if we're not threaded anymore, leave
   if (!g_threaded) {
@@ -168,30 +172,29 @@ static bool wait_until(gpr_timespec next) {
        unless their 'next' is earlier than the current timed-waiter's deadline
        (in which case the thread with earlier 'next' takes over as the new timed
        waiter) */
-    if (gpr_time_cmp(next, inf_future) != 0) {
-      if (!g_has_timed_waiter ||
-          (gpr_time_cmp(next, g_timed_waiter_deadline) < 0)) {
+    if (next != GRPC_MILLIS_INF_FUTURE) {
+      if (!g_has_timed_waiter || (next < g_timed_waiter_deadline)) {
         my_timed_waiter_generation = ++g_timed_waiter_generation;
         g_has_timed_waiter = true;
         g_timed_waiter_deadline = next;
 
         if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
-          gpr_timespec wait_time =
-              gpr_time_sub(next, gpr_now(GPR_CLOCK_MONOTONIC));
-          gpr_log(GPR_DEBUG, "sleep for a %" PRId64 ".%09d seconds",
-                  wait_time.tv_sec, wait_time.tv_nsec);
+          grpc_millis wait_time = next - grpc_exec_ctx_now(exec_ctx);
+          gpr_log(GPR_DEBUG, "sleep for a %" PRIdPTR " milliseconds",
+                  wait_time);
         }
       } else {  // g_timed_waiter == true && next >= g_timed_waiter_deadline
-        next = inf_future;
+        next = GRPC_MILLIS_INF_FUTURE;
       }
     }
 
     if (GRPC_TRACER_ON(grpc_timer_check_trace) &&
-        gpr_time_cmp(next, inf_future) == 0) {
+        next == GRPC_MILLIS_INF_FUTURE) {
       gpr_log(GPR_DEBUG, "sleep until kicked");
     }
 
-    gpr_cv_wait(&g_cv_wait, &g_mu, next);
+    gpr_cv_wait(&g_cv_wait, &g_mu,
+                grpc_millis_to_timespec(next, GPR_CLOCK_REALTIME));
 
     if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
       gpr_log(GPR_DEBUG, "wait ended: was_timed:%d kicked:%d",
@@ -203,7 +206,7 @@ static bool wait_until(gpr_timespec next) {
     // there's work to do after checking timers (code above)
     if (my_timed_waiter_generation == g_timed_waiter_generation) {
       g_has_timed_waiter = false;
-      g_timed_waiter_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+      g_timed_waiter_deadline = GRPC_MILLIS_INF_FUTURE;
     }
   }
 
@@ -219,12 +222,11 @@ static bool wait_until(gpr_timespec next) {
 }
 
 static void timer_main_loop(grpc_exec_ctx *exec_ctx) {
-  const gpr_timespec inf_future = gpr_inf_future(GPR_CLOCK_MONOTONIC);
   for (;;) {
-    gpr_timespec next = inf_future;
-    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    grpc_millis next = GRPC_MILLIS_INF_FUTURE;
+    grpc_exec_ctx_invalidate_now(exec_ctx);
     // check timer state, updates next to the next time to run a check
-    switch (grpc_timer_check(exec_ctx, now, &next)) {
+    switch (grpc_timer_check(exec_ctx, &next)) {
       case GRPC_TIMERS_FIRED:
         run_some_timers(exec_ctx);
         break;
@@ -241,10 +243,10 @@ static void timer_main_loop(grpc_exec_ctx *exec_ctx) {
         if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
           gpr_log(GPR_DEBUG, "timers not checked: expect another thread to");
         }
-        next = inf_future;
+        next = GRPC_MILLIS_INF_FUTURE;
       /* fall through */
       case GRPC_TIMERS_CHECKED_AND_EMPTY:
-        if (!wait_until(next)) {
+        if (!wait_until(exec_ctx, next)) {
           return;
         }
         break;
@@ -300,7 +302,7 @@ void grpc_timer_manager_init(void) {
   g_completed_threads = NULL;
 
   g_has_timed_waiter = false;
-  g_timed_waiter_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+  g_timed_waiter_deadline = GRPC_MILLIS_INF_FUTURE;
 
   start_threads();
 }
@@ -347,7 +349,7 @@ void grpc_kick_poller(void) {
   gpr_mu_lock(&g_mu);
   g_kicked = true;
   g_has_timed_waiter = false;
-  g_timed_waiter_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+  g_timed_waiter_deadline = GRPC_MILLIS_INF_FUTURE;
   ++g_timed_waiter_generation;
   gpr_cv_signal(&g_cv_wait);
   gpr_mu_unlock(&g_mu);
diff --git a/src/core/lib/iomgr/timer_manager.h b/src/core/lib/iomgr/timer_manager.h
index 0ba502928a..d8a59a9477 100644
--- a/src/core/lib/iomgr/timer_manager.h
+++ b/src/core/lib/iomgr/timer_manager.h
@@ -21,6 +21,10 @@
 
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Timer Manager tries to keep one thread waiting for the next timeout at all
    times */
 
@@ -34,4 +38,8 @@ void grpc_timer_manager_set_threading(bool enabled);
  * disabled */
 void grpc_timer_manager_tick(void);
 
-#endif /* GRPC_CORE_LIB_IOMGR_TIMER_MANAGER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_TIMER_MANAGER_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/timer_uv.c b/src/core/lib/iomgr/timer_uv.cc
index adced41f53..bd1e922c7f 100644
--- a/src/core/lib/iomgr/timer_uv.c
+++ b/src/core/lib/iomgr/timer_uv.cc
@@ -29,9 +29,11 @@
 
 #include <uv.h>
 
+extern "C" {
 grpc_tracer_flag grpc_timer_trace = GRPC_TRACER_INITIALIZER(false, "timer");
 grpc_tracer_flag grpc_timer_check_trace =
     GRPC_TRACER_INITIALIZER(false, "timer_check");
+}
 
 static void timer_close_callback(uv_handle_t *handle) { gpr_free(handle); }
 
@@ -53,20 +55,19 @@ void run_expired_timer(uv_timer_t *handle) {
 }
 
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_closure *closure,
-                     gpr_timespec now) {
+                     grpc_millis deadline, grpc_closure *closure) {
   uint64_t timeout;
   uv_timer_t *uv_timer;
   GRPC_UV_ASSERT_SAME_THREAD();
   timer->closure = closure;
-  if (gpr_time_cmp(deadline, now) <= 0) {
+  if (deadline <= grpc_exec_ctx_now(exec_ctx)) {
     timer->pending = 0;
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_NONE);
     return;
   }
   timer->pending = 1;
-  timeout = (uint64_t)gpr_time_to_millis(gpr_time_sub(deadline, now));
-  uv_timer = gpr_malloc(sizeof(uv_timer_t));
+  timeout = (uint64_t)(deadline - grpc_exec_ctx_now(exec_ctx));
+  uv_timer = (uv_timer_t *)gpr_malloc(sizeof(uv_timer_t));
   uv_timer_init(uv_default_loop(), uv_timer);
   uv_timer->data = timer;
   timer->uv_timer = uv_timer;
@@ -89,7 +90,7 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
 }
 
 grpc_timer_check_result grpc_timer_check(grpc_exec_ctx *exec_ctx,
-                                         gpr_timespec now, gpr_timespec *next) {
+                                         grpc_millis *next) {
   return GRPC_TIMERS_NOT_CHECKED;
 }
 
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.cc
index 00b2e68bb5..00b2e68bb5 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.cc
diff --git a/src/core/lib/iomgr/udp_server.h b/src/core/lib/iomgr/udp_server.h
index 881468ea2c..bcd8572260 100644
--- a/src/core/lib/iomgr/udp_server.h
+++ b/src/core/lib/iomgr/udp_server.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Forward decl of struct grpc_server */
 /* This is not typedef'ed to avoid a typedef-redefinition error */
 struct grpc_server;
@@ -73,4 +77,8 @@ int grpc_udp_server_add_port(grpc_udp_server *s,
 void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *server,
                              grpc_closure *on_done);
 
-#endif /* GRPC_CORE_LIB_IOMGR_UDP_SERVER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_UDP_SERVER_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/unix_sockets_posix.c b/src/core/lib/iomgr/unix_sockets_posix.cc
index 35f898f13a..35f898f13a 100644
--- a/src/core/lib/iomgr/unix_sockets_posix.c
+++ b/src/core/lib/iomgr/unix_sockets_posix.cc
diff --git a/src/core/lib/iomgr/unix_sockets_posix.h b/src/core/lib/iomgr/unix_sockets_posix.h
index 25b64b3eec..b96131ae1c 100644
--- a/src/core/lib/iomgr/unix_sockets_posix.h
+++ b/src/core/lib/iomgr/unix_sockets_posix.h
@@ -25,6 +25,10 @@
 
 #include "src/core/lib/iomgr/resolve_address.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void grpc_create_socketpair_if_unix(int sv[2]);
 
 grpc_error *grpc_resolve_unix_domain_address(
@@ -38,4 +42,8 @@ void grpc_unlink_if_unix_domain_socket(
 char *grpc_sockaddr_to_uri_unix_if_possible(
     const grpc_resolved_address *resolved_addr);
 
-#endif /* GRPC_CORE_LIB_IOMGR_UNIX_SOCKETS_POSIX_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_UNIX_SOCKETS_POSIX_H */
\ No newline at end of file
diff --git a/src/core/lib/iomgr/unix_sockets_posix_noop.c b/src/core/lib/iomgr/unix_sockets_posix_noop.cc
index e46b1c003d..e46b1c003d 100644
--- a/src/core/lib/iomgr/unix_sockets_posix_noop.c
+++ b/src/core/lib/iomgr/unix_sockets_posix_noop.cc
diff --git a/src/core/lib/iomgr/wakeup_fd_cv.c b/src/core/lib/iomgr/wakeup_fd_cv.cc
index 268e0175dd..268e0175dd 100644
--- a/src/core/lib/iomgr/wakeup_fd_cv.c
+++ b/src/core/lib/iomgr/wakeup_fd_cv.cc
diff --git a/src/core/lib/iomgr/wakeup_fd_cv.h b/src/core/lib/iomgr/wakeup_fd_cv.h
index dc170ad5b4..dcd7bdb560 100644
--- a/src/core/lib/iomgr/wakeup_fd_cv.h
+++ b/src/core/lib/iomgr/wakeup_fd_cv.h
@@ -40,6 +40,10 @@
 #define GRPC_FD_TO_IDX(fd) (-(fd)-1)
 #define GRPC_IDX_TO_FD(idx) (-(idx)-1)
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct cv_node {
   gpr_cv* cv;
   struct cv_node* next;
@@ -62,4 +66,10 @@ typedef struct cv_fd_table {
   grpc_poll_function_type poll;
 } cv_fd_table;
 
+extern const grpc_wakeup_fd_vtable grpc_cv_wakeup_fd_vtable;
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H */
diff --git a/src/core/lib/iomgr/wakeup_fd_eventfd.c b/src/core/lib/iomgr/wakeup_fd_eventfd.cc
index 81cb7ee280..81cb7ee280 100644
--- a/src/core/lib/iomgr/wakeup_fd_eventfd.c
+++ b/src/core/lib/iomgr/wakeup_fd_eventfd.cc
diff --git a/src/core/lib/iomgr/wakeup_fd_nospecial.c b/src/core/lib/iomgr/wakeup_fd_nospecial.cc
index 4c20b8c1b7..4c20b8c1b7 100644
--- a/src/core/lib/iomgr/wakeup_fd_nospecial.c
+++ b/src/core/lib/iomgr/wakeup_fd_nospecial.cc
diff --git a/src/core/lib/iomgr/wakeup_fd_pipe.c b/src/core/lib/iomgr/wakeup_fd_pipe.cc
index 4189488f8a..05d69dc9cc 100644
--- a/src/core/lib/iomgr/wakeup_fd_pipe.c
+++ b/src/core/lib/iomgr/wakeup_fd_pipe.cc
@@ -20,6 +20,7 @@
 
 #ifdef GRPC_POSIX_WAKEUP_FD
 
+#include "src/core/lib/iomgr/wakeup_fd_pipe.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
 #include <errno.h>
diff --git a/src/core/lib/iomgr/wakeup_fd_pipe.h b/src/core/lib/iomgr/wakeup_fd_pipe.h
index f860406bda..9bbb5e2ff7 100644
--- a/src/core/lib/iomgr/wakeup_fd_pipe.h
+++ b/src/core/lib/iomgr/wakeup_fd_pipe.h
@@ -21,6 +21,14 @@
 
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
-extern grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable;
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern const grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable;
+
+#ifdef __cplusplus
+}
+#endif
 
 #endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_PIPE_H */
diff --git a/src/core/lib/iomgr/wakeup_fd_posix.c b/src/core/lib/iomgr/wakeup_fd_posix.cc
index 25daa7d3fb..9af96d314b 100644
--- a/src/core/lib/iomgr/wakeup_fd_posix.c
+++ b/src/core/lib/iomgr/wakeup_fd_posix.cc
@@ -25,7 +25,6 @@
 #include "src/core/lib/iomgr/wakeup_fd_pipe.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
-extern grpc_wakeup_fd_vtable grpc_cv_wakeup_fd_vtable;
 static const grpc_wakeup_fd_vtable *wakeup_fd_vtable = NULL;
 
 int grpc_allow_specialized_wakeup_fd = 1;
diff --git a/src/core/lib/iomgr/wakeup_fd_posix.h b/src/core/lib/iomgr/wakeup_fd_posix.h
index a9584d0d48..ae7849f98c 100644
--- a/src/core/lib/iomgr/wakeup_fd_posix.h
+++ b/src/core/lib/iomgr/wakeup_fd_posix.h
@@ -49,6 +49,10 @@
 
 #include "src/core/lib/iomgr/error.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void grpc_wakeup_fd_global_init(void);
 void grpc_wakeup_fd_global_destroy(void);
 
@@ -91,4 +95,8 @@ void grpc_wakeup_fd_destroy(grpc_wakeup_fd* fd_info);
  * wakeup_fd_nospecial.c if no such implementation exists. */
 extern const grpc_wakeup_fd_vtable grpc_specialized_wakeup_fd_vtable;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_POSIX_H */
diff --git a/src/core/lib/json/json.c b/src/core/lib/json/json.cc
index 4ad51f662a..4ad51f662a 100644
--- a/src/core/lib/json/json.c
+++ b/src/core/lib/json/json.cc
diff --git a/src/core/lib/json/json.h b/src/core/lib/json/json.h
index bbd43025eb..81b7e0c9da 100644
--- a/src/core/lib/json/json.h
+++ b/src/core/lib/json/json.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/json/json_common.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* A tree-like structure to hold json values. The key and value pointers
  * are not owned by it.
  */
@@ -70,4 +74,8 @@ char* grpc_json_dump_to_string(grpc_json* json, int indent);
 grpc_json* grpc_json_create(grpc_json_type type);
 void grpc_json_destroy(grpc_json* json);
 
-#endif /* GRPC_CORE_LIB_JSON_JSON_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_H */
\ No newline at end of file
diff --git a/src/core/lib/json/json_reader.c b/src/core/lib/json/json_reader.cc
index 094a35176c..094a35176c 100644
--- a/src/core/lib/json/json_reader.c
+++ b/src/core/lib/json/json_reader.cc
diff --git a/src/core/lib/json/json_reader.h b/src/core/lib/json/json_reader.h
index 577fbbbaf6..ab2384f7a7 100644
--- a/src/core/lib/json/json_reader.h
+++ b/src/core/lib/json/json_reader.h
@@ -22,6 +22,10 @@
 #include <grpc/support/port_platform.h>
 #include "src/core/lib/json/json_common.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   GRPC_JSON_STATE_OBJECT_KEY_BEGIN,
   GRPC_JSON_STATE_OBJECT_KEY_STRING,
@@ -142,4 +146,8 @@ void grpc_json_reader_init(grpc_json_reader *reader,
  */
 int grpc_json_reader_is_complete(grpc_json_reader *reader);
 
-#endif /* GRPC_CORE_LIB_JSON_JSON_READER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_READER_H */
\ No newline at end of file
diff --git a/src/core/lib/json/json_string.c b/src/core/lib/json/json_string.cc
index 3178d2d2b4..3178d2d2b4 100644
--- a/src/core/lib/json/json_string.c
+++ b/src/core/lib/json/json_string.cc
diff --git a/src/core/lib/json/json_writer.c b/src/core/lib/json/json_writer.cc
index eab1bff7a6..eab1bff7a6 100644
--- a/src/core/lib/json/json_writer.c
+++ b/src/core/lib/json/json_writer.cc
diff --git a/src/core/lib/json/json_writer.h b/src/core/lib/json/json_writer.h
index 8779039d42..18bd2a80fe 100644
--- a/src/core/lib/json/json_writer.h
+++ b/src/core/lib/json/json_writer.h
@@ -35,6 +35,10 @@
 
 #include "src/core/lib/json/json_common.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_json_writer_vtable {
   /* Adds a character to the output stream. */
   void (*output_char)(void *userdata, char);
@@ -79,4 +83,8 @@ void grpc_json_writer_value_raw_with_len(grpc_json_writer *writer,
 void grpc_json_writer_value_string(grpc_json_writer *writer,
                                    const char *string);
 
-#endif /* GRPC_CORE_LIB_JSON_JSON_WRITER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_WRITER_H */
\ No newline at end of file
diff --git a/src/core/lib/profiling/basic_timers.c b/src/core/lib/profiling/basic_timers.cc
index c7645b74f2..ab9d60481c 100644
--- a/src/core/lib/profiling/basic_timers.c
+++ b/src/core/lib/profiling/basic_timers.cc
@@ -18,10 +18,10 @@
 
 #include <grpc/support/port_platform.h>
 
-#ifdef GRPC_BASIC_PROFILER
-
 #include "src/core/lib/profiling/timers.h"
 
+#ifdef GRPC_BASIC_PROFILER
+
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
diff --git a/src/core/lib/profiling/stap_timers.c b/src/core/lib/profiling/stap_timers.cc
index c86d74f058..c86d74f058 100644
--- a/src/core/lib/profiling/stap_timers.c
+++ b/src/core/lib/profiling/stap_timers.cc
diff --git a/src/core/lib/security/context/security_context.c b/src/core/lib/security/context/security_context.cc
index 8fff2c92c5..31d800b9b4 100644
--- a/src/core/lib/security/context/security_context.c
+++ b/src/core/lib/security/context/security_context.cc
@@ -82,7 +82,8 @@ void grpc_auth_context_release(grpc_auth_context *context) {
 /* --- grpc_client_security_context --- */
 
 grpc_client_security_context *grpc_client_security_context_create(void) {
-  return gpr_zalloc(sizeof(grpc_client_security_context));
+  return (grpc_client_security_context *)gpr_zalloc(
+      sizeof(grpc_client_security_context));
 }
 
 void grpc_client_security_context_destroy(void *ctx) {
@@ -100,7 +101,8 @@ void grpc_client_security_context_destroy(void *ctx) {
 /* --- grpc_server_security_context --- */
 
 grpc_server_security_context *grpc_server_security_context_create(void) {
-  return gpr_zalloc(sizeof(grpc_server_security_context));
+  return (grpc_server_security_context *)gpr_zalloc(
+      sizeof(grpc_server_security_context));
 }
 
 void grpc_server_security_context_destroy(void *ctx) {
@@ -117,7 +119,8 @@ void grpc_server_security_context_destroy(void *ctx) {
 static grpc_auth_property_iterator empty_iterator = {NULL, 0, NULL};
 
 grpc_auth_context *grpc_auth_context_create(grpc_auth_context *chained) {
-  grpc_auth_context *ctx = gpr_zalloc(sizeof(grpc_auth_context));
+  grpc_auth_context *ctx =
+      (grpc_auth_context *)gpr_zalloc(sizeof(grpc_auth_context));
   gpr_ref_init(&ctx->refcount, 1);
   if (chained != NULL) {
     ctx->chained = GRPC_AUTH_CONTEXT_REF(chained, "chained");
@@ -258,9 +261,9 @@ static void ensure_auth_context_capacity(grpc_auth_context *ctx) {
   if (ctx->properties.count == ctx->properties.capacity) {
     ctx->properties.capacity =
         GPR_MAX(ctx->properties.capacity + 8, ctx->properties.capacity * 2);
-    ctx->properties.array =
-        gpr_realloc(ctx->properties.array,
-                    ctx->properties.capacity * sizeof(grpc_auth_property));
+    ctx->properties.array = (grpc_auth_property *)gpr_realloc(
+        ctx->properties.array,
+        ctx->properties.capacity * sizeof(grpc_auth_property));
   }
 }
 
@@ -275,7 +278,7 @@ void grpc_auth_context_add_property(grpc_auth_context *ctx, const char *name,
   ensure_auth_context_capacity(ctx);
   prop = &ctx->properties.array[ctx->properties.count++];
   prop->name = gpr_strdup(name);
-  prop->value = gpr_malloc(value_length + 1);
+  prop->value = (char *)gpr_malloc(value_length + 1);
   memcpy(prop->value, value, value_length);
   prop->value[value_length] = '\0';
   prop->value_length = value_length;
@@ -302,11 +305,12 @@ void grpc_auth_property_reset(grpc_auth_property *property) {
 }
 
 static void auth_context_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
-  GRPC_AUTH_CONTEXT_UNREF(p, "auth_context_pointer_arg");
+  GRPC_AUTH_CONTEXT_UNREF((grpc_auth_context *)p, "auth_context_pointer_arg");
 }
 
 static void *auth_context_pointer_arg_copy(void *p) {
-  return GRPC_AUTH_CONTEXT_REF(p, "auth_context_pointer_arg");
+  return GRPC_AUTH_CONTEXT_REF((grpc_auth_context *)p,
+                               "auth_context_pointer_arg");
 }
 
 static int auth_context_pointer_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
@@ -316,7 +320,7 @@ static const grpc_arg_pointer_vtable auth_context_pointer_vtable = {
     auth_context_pointer_cmp};
 
 grpc_arg grpc_auth_context_to_arg(grpc_auth_context *p) {
-  return grpc_channel_arg_pointer_create(GRPC_AUTH_CONTEXT_ARG, p,
+  return grpc_channel_arg_pointer_create((char *)GRPC_AUTH_CONTEXT_ARG, p,
                                          &auth_context_pointer_vtable);
 }
 
@@ -327,7 +331,7 @@ grpc_auth_context *grpc_auth_context_from_arg(const grpc_arg *arg) {
             GRPC_AUTH_CONTEXT_ARG);
     return NULL;
   }
-  return arg->value.pointer.p;
+  return (grpc_auth_context *)arg->value.pointer.p;
 }
 
 grpc_auth_context *grpc_find_auth_context_in_args(
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.cc
index 09fd60a12c..779300ac07 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.cc
@@ -79,7 +79,8 @@ static bool composite_call_get_request_metadata(
     grpc_error **error) {
   grpc_composite_call_credentials *c = (grpc_composite_call_credentials *)creds;
   grpc_composite_call_credentials_metadata_context *ctx;
-  ctx = gpr_zalloc(sizeof(grpc_composite_call_credentials_metadata_context));
+  ctx = (grpc_composite_call_credentials_metadata_context *)gpr_zalloc(
+      sizeof(grpc_composite_call_credentials_metadata_context));
   ctx->composite_creds = c;
   ctx->pollent = pollent;
   ctx->auth_md_context = auth_md_context;
@@ -87,6 +88,7 @@ static bool composite_call_get_request_metadata(
   ctx->on_request_metadata = on_request_metadata;
   GRPC_CLOSURE_INIT(&ctx->internal_on_request_metadata,
                     composite_call_metadata_cb, ctx, grpc_schedule_on_exec_ctx);
+  bool synchronous = true;
   while (ctx->creds_index < ctx->composite_creds->inner.num_creds) {
     grpc_call_credentials *inner_creds =
         ctx->composite_creds->inner.creds_array[ctx->creds_index++];
@@ -95,19 +97,12 @@ static bool composite_call_get_request_metadata(
             ctx->md_array, &ctx->internal_on_request_metadata, error)) {
       if (*error != GRPC_ERROR_NONE) break;
     } else {
+      synchronous = false;  // Async return.
       break;
     }
   }
-  // If we got through all creds synchronously or we got a synchronous
-  // error on one of them, return synchronously.
-  if (ctx->creds_index == ctx->composite_creds->inner.num_creds ||
-      *error != GRPC_ERROR_NONE) {
-    gpr_free(ctx);
-    return true;
-  }
-  // At least one inner cred is returning asynchronously, so we'll
-  // return asynchronously as well.
-  return false;
+  if (synchronous) gpr_free(ctx);
+  return synchronous;
 }
 
 static void composite_call_cancel_get_request_metadata(
@@ -152,7 +147,8 @@ grpc_call_credentials *grpc_composite_call_credentials_create(
   GPR_ASSERT(reserved == NULL);
   GPR_ASSERT(creds1 != NULL);
   GPR_ASSERT(creds2 != NULL);
-  c = gpr_zalloc(sizeof(grpc_composite_call_credentials));
+  c = (grpc_composite_call_credentials *)gpr_zalloc(
+      sizeof(grpc_composite_call_credentials));
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_COMPOSITE;
   c->base.vtable = &composite_call_credentials_vtable;
   gpr_ref_init(&c->base.refcount, 1);
@@ -160,7 +156,8 @@ grpc_call_credentials *grpc_composite_call_credentials_create(
   creds2_array = get_creds_array(&creds2);
   c->inner.num_creds = creds1_array.num_creds + creds2_array.num_creds;
   creds_array_byte_size = c->inner.num_creds * sizeof(grpc_call_credentials *);
-  c->inner.creds_array = gpr_zalloc(creds_array_byte_size);
+  c->inner.creds_array =
+      (grpc_call_credentials **)gpr_zalloc(creds_array_byte_size);
   for (i = 0; i < creds1_array.num_creds; i++) {
     grpc_call_credentials *cur_creds = creds1_array.creds_array[i];
     c->inner.creds_array[i] = grpc_call_credentials_ref(cur_creds);
@@ -254,7 +251,8 @@ static grpc_channel_credentials_vtable composite_channel_credentials_vtable = {
 grpc_channel_credentials *grpc_composite_channel_credentials_create(
     grpc_channel_credentials *channel_creds, grpc_call_credentials *call_creds,
     void *reserved) {
-  grpc_composite_channel_credentials *c = gpr_zalloc(sizeof(*c));
+  grpc_composite_channel_credentials *c =
+      (grpc_composite_channel_credentials *)gpr_zalloc(sizeof(*c));
   GPR_ASSERT(channel_creds != NULL && call_creds != NULL && reserved == NULL);
   GRPC_API_TRACE(
       "grpc_composite_channel_credentials_create(channel_creds=%p, "
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.h b/src/core/lib/security/credentials/composite/composite_credentials.h
index 3076afcb7e..6e9f9a8f6f 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.h
+++ b/src/core/lib/security/credentials/composite/composite_credentials.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
   grpc_call_credentials **creds_array;
   size_t num_creds;
@@ -53,5 +57,9 @@ typedef struct {
   grpc_call_credentials_array inner;
 } grpc_composite_call_credentials;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_COMPOSITE_COMPOSITE_CREDENTIALS_H \
           */
diff --git a/src/core/lib/security/credentials/credentials.c b/src/core/lib/security/credentials/credentials.cc
index 8a67c9865b..ebbf350865 100644
--- a/src/core/lib/security/credentials/credentials.c
+++ b/src/core/lib/security/credentials/credentials.cc
@@ -40,7 +40,8 @@
 grpc_credentials_metadata_request *grpc_credentials_metadata_request_create(
     grpc_call_credentials *creds) {
   grpc_credentials_metadata_request *r =
-      gpr_zalloc(sizeof(grpc_credentials_metadata_request));
+      (grpc_credentials_metadata_request *)gpr_zalloc(
+          sizeof(grpc_credentials_metadata_request));
   r->creds = grpc_call_credentials_ref(creds);
   return r;
 }
@@ -148,11 +149,11 @@ grpc_channel_credentials_duplicate_without_call_credentials(
 }
 
 static void credentials_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
-  grpc_channel_credentials_unref(exec_ctx, p);
+  grpc_channel_credentials_unref(exec_ctx, (grpc_channel_credentials *)p);
 }
 
 static void *credentials_pointer_arg_copy(void *p) {
-  return grpc_channel_credentials_ref(p);
+  return grpc_channel_credentials_ref((grpc_channel_credentials *)p);
 }
 
 static int credentials_pointer_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
@@ -163,8 +164,9 @@ static const grpc_arg_pointer_vtable credentials_pointer_vtable = {
 
 grpc_arg grpc_channel_credentials_to_arg(
     grpc_channel_credentials *credentials) {
-  return grpc_channel_arg_pointer_create(
-      GRPC_ARG_CHANNEL_CREDENTIALS, credentials, &credentials_pointer_vtable);
+  return grpc_channel_arg_pointer_create((char *)GRPC_ARG_CHANNEL_CREDENTIALS,
+                                         credentials,
+                                         &credentials_pointer_vtable);
 }
 
 grpc_channel_credentials *grpc_channel_credentials_from_arg(
@@ -175,7 +177,7 @@ grpc_channel_credentials *grpc_channel_credentials_from_arg(
             GRPC_ARG_CHANNEL_CREDENTIALS);
     return NULL;
   }
-  return arg->value.pointer.p;
+  return (grpc_channel_credentials *)arg->value.pointer.p;
 }
 
 grpc_channel_credentials *grpc_channel_credentials_find_in_args(
@@ -244,11 +246,11 @@ void grpc_server_credentials_set_auth_metadata_processor(
 
 static void server_credentials_pointer_arg_destroy(grpc_exec_ctx *exec_ctx,
                                                    void *p) {
-  grpc_server_credentials_unref(exec_ctx, p);
+  grpc_server_credentials_unref(exec_ctx, (grpc_server_credentials *)p);
 }
 
 static void *server_credentials_pointer_arg_copy(void *p) {
-  return grpc_server_credentials_ref(p);
+  return grpc_server_credentials_ref((grpc_server_credentials *)p);
 }
 
 static int server_credentials_pointer_cmp(void *a, void *b) {
@@ -260,7 +262,7 @@ static const grpc_arg_pointer_vtable cred_ptr_vtable = {
     server_credentials_pointer_cmp};
 
 grpc_arg grpc_server_credentials_to_arg(grpc_server_credentials *p) {
-  return grpc_channel_arg_pointer_create(GRPC_SERVER_CREDENTIALS_ARG, p,
+  return grpc_channel_arg_pointer_create((char *)GRPC_SERVER_CREDENTIALS_ARG, p,
                                          &cred_ptr_vtable);
 }
 
@@ -271,7 +273,7 @@ grpc_server_credentials *grpc_server_credentials_from_arg(const grpc_arg *arg) {
             GRPC_SERVER_CREDENTIALS_ARG);
     return NULL;
   }
-  return arg->value.pointer.p;
+  return (grpc_server_credentials *)arg->value.pointer.p;
 }
 
 grpc_server_credentials *grpc_find_server_credentials_in_args(
diff --git a/src/core/lib/security/credentials/credentials.h b/src/core/lib/security/credentials/credentials.h
index 04a54b0ca8..73e39ae039 100644
--- a/src/core/lib/security/credentials/credentials.h
+++ b/src/core/lib/security/credentials/credentials.h
@@ -29,6 +29,10 @@
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/security/transport/security_connector.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct grpc_http_response;
 
 /* --- Constants. --- */
@@ -252,4 +256,8 @@ grpc_credentials_metadata_request *grpc_credentials_metadata_request_create(
 void grpc_credentials_metadata_request_destroy(
     grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *r);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_CREDENTIALS_H */
diff --git a/src/core/lib/security/credentials/credentials_metadata.c b/src/core/lib/security/credentials/credentials_metadata.cc
index ccd39e610f..5ba98bda4e 100644
--- a/src/core/lib/security/credentials/credentials_metadata.c
+++ b/src/core/lib/security/credentials/credentials_metadata.cc
@@ -33,7 +33,8 @@ static void mdelem_list_ensure_capacity(grpc_credentials_mdelem_array *list,
   while (new_size < target_size) {
     new_size *= 2;
   }
-  list->md = gpr_realloc(list->md, sizeof(grpc_mdelem) * new_size);
+  list->md =
+      (grpc_mdelem *)gpr_realloc(list->md, sizeof(grpc_mdelem) * new_size);
 }
 
 void grpc_credentials_mdelem_array_add(grpc_credentials_mdelem_array *list,
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.cc
index ac9017850f..795ca0660a 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.cc
@@ -60,7 +60,8 @@ static grpc_server_credentials_vtable
 
 grpc_channel_credentials *grpc_fake_transport_security_credentials_create(
     void) {
-  grpc_channel_credentials *c = gpr_zalloc(sizeof(grpc_channel_credentials));
+  grpc_channel_credentials *c =
+      (grpc_channel_credentials *)gpr_zalloc(sizeof(grpc_channel_credentials));
   c->type = GRPC_CHANNEL_CREDENTIALS_TYPE_FAKE_TRANSPORT_SECURITY;
   c->vtable = &fake_transport_security_credentials_vtable;
   gpr_ref_init(&c->refcount, 1);
@@ -69,7 +70,8 @@ grpc_channel_credentials *grpc_fake_transport_security_credentials_create(
 
 grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
     void) {
-  grpc_server_credentials *c = gpr_malloc(sizeof(grpc_server_credentials));
+  grpc_server_credentials *c =
+      (grpc_server_credentials *)gpr_malloc(sizeof(grpc_server_credentials));
   memset(c, 0, sizeof(grpc_server_credentials));
   c->type = GRPC_CHANNEL_CREDENTIALS_TYPE_FAKE_TRANSPORT_SECURITY;
   gpr_ref_init(&c->refcount, 1);
@@ -78,8 +80,8 @@ grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
 }
 
 grpc_arg grpc_fake_transport_expected_targets_arg(char *expected_targets) {
-  return grpc_channel_arg_string_create(GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS,
-                                        expected_targets);
+  return grpc_channel_arg_string_create(
+      (char *)GRPC_ARG_FAKE_SECURITY_EXPECTED_TARGETS, expected_targets);
 }
 
 const char *grpc_fake_transport_get_expected_targets(
@@ -129,7 +131,8 @@ grpc_call_credentials *grpc_md_only_test_credentials_create(
     grpc_exec_ctx *exec_ctx, const char *md_key, const char *md_value,
     bool is_async) {
   grpc_md_only_test_credentials *c =
-      gpr_zalloc(sizeof(grpc_md_only_test_credentials));
+      (grpc_md_only_test_credentials *)gpr_zalloc(
+          sizeof(grpc_md_only_test_credentials));
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_OAUTH2;
   c->base.vtable = &md_only_test_vtable;
   gpr_ref_init(&c->base.refcount, 1);
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.h b/src/core/lib/security/credentials/fake/fake_credentials.h
index aa0f3b6e20..64f6f439f0 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.h
+++ b/src/core/lib/security/credentials/fake/fake_credentials.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* -- Fake transport security credentials. -- */
 
 /* Creates a fake transport security credentials object for testing. */
@@ -56,4 +60,8 @@ typedef struct {
   bool is_async;
 } grpc_md_only_test_credentials;
 
-#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_FAKE_FAKE_CREDENTIALS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_FAKE_FAKE_CREDENTIALS_H */
\ No newline at end of file
diff --git a/src/core/lib/security/credentials/google_default/credentials_generic.c b/src/core/lib/security/credentials/google_default/credentials_generic.cc
index 4f79718f3d..4f79718f3d 100644
--- a/src/core/lib/security/credentials/google_default/credentials_generic.c
+++ b/src/core/lib/security/credentials/google_default/credentials_generic.cc
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.c b/src/core/lib/security/credentials/google_default/google_default_credentials.cc
index 691d66df69..5b2ddceb4a 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.c
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.cc
@@ -28,6 +28,7 @@
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/iomgr/load_file.h"
 #include "src/core/lib/iomgr/polling_entity.h"
+#include "src/core/lib/security/credentials/google_default/google_default_credentials.h"
 #include "src/core/lib/security/credentials/jwt/jwt_credentials.h"
 #include "src/core/lib/security/credentials/oauth2/oauth2_credentials.h"
 #include "src/core/lib/slice/slice_internal.h"
@@ -85,7 +86,7 @@ static void on_compute_engine_detection_http_response(grpc_exec_ctx *exec_ctx,
 }
 
 static void destroy_pollset(grpc_exec_ctx *exec_ctx, void *p, grpc_error *e) {
-  grpc_pollset_destroy(exec_ctx, p);
+  grpc_pollset_destroy(exec_ctx, (grpc_pollset *)p);
 }
 
 static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
@@ -96,9 +97,9 @@ static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
 
   /* The http call is local. If it takes more than one sec, it is for sure not
      on compute engine. */
-  gpr_timespec max_detection_delay = gpr_time_from_seconds(1, GPR_TIMESPAN);
+  grpc_millis max_detection_delay = GPR_MS_PER_SEC;
 
-  grpc_pollset *pollset = gpr_zalloc(grpc_pollset_size());
+  grpc_pollset *pollset = (grpc_pollset *)gpr_zalloc(grpc_pollset_size());
   grpc_pollset_init(pollset, &g_polling_mu);
   detector.pollent = grpc_polling_entity_create_from_pollset(pollset);
   detector.is_done = 0;
@@ -106,8 +107,8 @@ static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
 
   memset(&detector.response, 0, sizeof(detector.response));
   memset(&request, 0, sizeof(grpc_httpcli_request));
-  request.host = GRPC_COMPUTE_ENGINE_DETECTION_HOST;
-  request.http.path = "/";
+  request.host = (char *)GRPC_COMPUTE_ENGINE_DETECTION_HOST;
+  request.http.path = (char *)"/";
 
   grpc_httpcli_context_init(&context);
 
@@ -115,7 +116,7 @@ static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
       grpc_resource_quota_create("google_default_credentials");
   grpc_httpcli_get(
       exec_ctx, &context, &detector.pollent, resource_quota, &request,
-      gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), max_detection_delay),
+      grpc_exec_ctx_now(exec_ctx) + max_detection_delay,
       GRPC_CLOSURE_CREATE(on_compute_engine_detection_http_response, &detector,
                           grpc_schedule_on_exec_ctx),
       &detector.response);
@@ -132,8 +133,7 @@ static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
             "pollset_work",
             grpc_pollset_work(exec_ctx,
                               grpc_polling_entity_pollset(&detector.pollent),
-                              &worker, gpr_now(GPR_CLOCK_MONOTONIC),
-                              gpr_inf_future(GPR_CLOCK_MONOTONIC)))) {
+                              &worker, GRPC_MILLIS_INF_FUTURE))) {
       detector.is_done = 1;
       detector.success = 0;
     }
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.h b/src/core/lib/security/credentials/google_default/google_default_credentials.h
index c3755e01a6..66677873ca 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.h
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "gcloud"
 #define GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE \
   "application_default_credentials.json"
@@ -41,5 +45,9 @@
 
 void grpc_flush_cached_google_default_credentials(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H \
           */
diff --git a/src/core/lib/security/credentials/iam/iam_credentials.c b/src/core/lib/security/credentials/iam/iam_credentials.cc
index 3de8319d98..e9cf208c16 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.c
+++ b/src/core/lib/security/credentials/iam/iam_credentials.cc
@@ -64,7 +64,8 @@ grpc_call_credentials *grpc_google_iam_credentials_create(
   GPR_ASSERT(reserved == NULL);
   GPR_ASSERT(token != NULL);
   GPR_ASSERT(authority_selector != NULL);
-  grpc_google_iam_credentials *c = gpr_zalloc(sizeof(*c));
+  grpc_google_iam_credentials *c =
+      (grpc_google_iam_credentials *)gpr_zalloc(sizeof(*c));
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_IAM;
   c->base.vtable = &iam_vtable;
   gpr_ref_init(&c->base.refcount, 1);
diff --git a/src/core/lib/security/credentials/jwt/json_token.c b/src/core/lib/security/credentials/jwt/json_token.cc
index fff71255a5..8c30353470 100644
--- a/src/core/lib/security/credentials/jwt/json_token.c
+++ b/src/core/lib/security/credentials/jwt/json_token.cc
@@ -20,6 +20,7 @@
 
 #include <string.h>
 
+#include <grpc/grpc_security.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -29,9 +30,11 @@
 #include "src/core/lib/slice/b64.h"
 #include "src/core/lib/support/string.h"
 
+extern "C" {
 #include <openssl/bio.h>
 #include <openssl/evp.h>
 #include <openssl/pem.h>
+}
 
 /* --- Constants. --- */
 
@@ -96,7 +99,7 @@ grpc_auth_json_key grpc_auth_json_key_create_from_json(const grpc_json *json) {
     gpr_log(GPR_ERROR, "Could not write into openssl BIO.");
     goto end;
   }
-  result.private_key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, "");
+  result.private_key = PEM_read_bio_RSAPrivateKey(bio, NULL, NULL, (void *)"");
   if (result.private_key == NULL) {
     gpr_log(GPR_ERROR, "Could not deserialize private key.");
     goto end;
@@ -214,7 +217,7 @@ static char *dot_concat_and_free_strings(char *str1, char *str2) {
   size_t str1_len = strlen(str1);
   size_t str2_len = strlen(str2);
   size_t result_len = str1_len + 1 /* dot */ + str2_len;
-  char *result = gpr_malloc(result_len + 1 /* NULL terminated */);
+  char *result = (char *)gpr_malloc(result_len + 1 /* NULL terminated */);
   char *current = result;
   memcpy(current, str1, str1_len);
   current += str1_len;
@@ -266,7 +269,7 @@ char *compute_and_encode_signature(const grpc_auth_json_key *json_key,
     gpr_log(GPR_ERROR, "DigestFinal (get signature length) failed.");
     goto end;
   }
-  sig = gpr_malloc(sig_len);
+  sig = (unsigned char *)gpr_malloc(sig_len);
   if (EVP_DigestSignFinal(md_ctx, sig, &sig_len) != 1) {
     gpr_log(GPR_ERROR, "DigestFinal (signature compute) failed.");
     goto end;
diff --git a/src/core/lib/security/credentials/jwt/json_token.h b/src/core/lib/security/credentials/jwt/json_token.h
index e50790ef2e..b923b02df6 100644
--- a/src/core/lib/security/credentials/jwt/json_token.h
+++ b/src/core/lib/security/credentials/jwt/json_token.h
@@ -19,6 +19,10 @@
 #ifndef GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JSON_TOKEN_H
 #define GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JSON_TOKEN_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <grpc/slice.h>
 #include <openssl/rsa.h>
 
@@ -70,4 +74,8 @@ typedef char *(*grpc_jwt_encode_and_sign_override)(
 void grpc_jwt_encode_and_sign_set_override(
     grpc_jwt_encode_and_sign_override func);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JSON_TOKEN_H */
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.c b/src/core/lib/security/credentials/jwt/jwt_credentials.cc
index 02c82e99ba..835dd677ed 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.c
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.cc
@@ -16,8 +16,11 @@
  *
  */
 
+#include <grpc/support/port_platform.h>
+
 #include "src/core/lib/security/credentials/jwt/jwt_credentials.h"
 
+#include <inttypes.h>
 #include <string.h>
 
 #include "src/core/lib/surface/api_trace.h"
@@ -125,7 +128,8 @@ grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
     gpr_log(GPR_ERROR, "Invalid input for jwt credentials creation");
     return NULL;
   }
-  c = gpr_zalloc(sizeof(grpc_service_account_jwt_access_credentials));
+  c = (grpc_service_account_jwt_access_credentials *)gpr_zalloc(
+      sizeof(grpc_service_account_jwt_access_credentials));
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_JWT;
   gpr_ref_init(&c->base.refcount, 1);
   c->base.vtable = &jwt_vtable;
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.h b/src/core/lib/security/credentials/jwt/jwt_credentials.h
index 07f4022669..c09485fd55 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.h
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.h
@@ -22,6 +22,10 @@
 #include "src/core/lib/security/credentials/credentials.h"
 #include "src/core/lib/security/credentials/jwt/json_token.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct {
   grpc_call_credentials base;
 
@@ -45,4 +49,8 @@ grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
     grpc_exec_ctx *exec_ctx, grpc_auth_json_key key,
     gpr_timespec token_lifetime);
 
-#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_CREDENTIALS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_CREDENTIALS_H */
\ No newline at end of file
diff --git a/src/core/lib/security/credentials/jwt/jwt_verifier.c b/src/core/lib/security/credentials/jwt/jwt_verifier.cc
index a27284bc50..39e72c195b 100644
--- a/src/core/lib/security/credentials/jwt/jwt_verifier.c
+++ b/src/core/lib/security/credentials/jwt/jwt_verifier.cc
@@ -26,7 +26,10 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/useful.h>
+
+extern "C" {
 #include <openssl/pem.h>
+}
 
 #include "src/core/lib/http/httpcli.h"
 #include "src/core/lib/iomgr/polling_entity.h"
@@ -129,7 +132,7 @@ static void jose_header_destroy(grpc_exec_ctx *exec_ctx, jose_header *h) {
 static jose_header *jose_header_from_json(grpc_exec_ctx *exec_ctx,
                                           grpc_json *json, grpc_slice buffer) {
   grpc_json *cur;
-  jose_header *h = gpr_zalloc(sizeof(jose_header));
+  jose_header *h = (jose_header *)gpr_zalloc(sizeof(jose_header));
   h->buffer = buffer;
   for (cur = json->child; cur != NULL; cur = cur->next) {
     if (strcmp(cur->key, "alg") == 0) {
@@ -231,7 +234,8 @@ gpr_timespec grpc_jwt_claims_not_before(const grpc_jwt_claims *claims) {
 grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_exec_ctx *exec_ctx,
                                            grpc_json *json, grpc_slice buffer) {
   grpc_json *cur;
-  grpc_jwt_claims *claims = gpr_malloc(sizeof(grpc_jwt_claims));
+  grpc_jwt_claims *claims =
+      (grpc_jwt_claims *)gpr_malloc(sizeof(grpc_jwt_claims));
   memset(claims, 0, sizeof(grpc_jwt_claims));
   claims->json = json;
   claims->buffer = buffer;
@@ -347,7 +351,7 @@ static verifier_cb_ctx *verifier_cb_ctx_create(
     const char *signed_jwt, size_t signed_jwt_len, void *user_data,
     grpc_jwt_verification_done_cb cb) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  verifier_cb_ctx *ctx = gpr_zalloc(sizeof(verifier_cb_ctx));
+  verifier_cb_ctx *ctx = (verifier_cb_ctx *)gpr_zalloc(sizeof(verifier_cb_ctx));
   ctx->verifier = verifier;
   ctx->pollent = grpc_polling_entity_create_from_pollset(pollset);
   ctx->header = header;
@@ -380,7 +384,7 @@ void verifier_cb_ctx_destroy(grpc_exec_ctx *exec_ctx, verifier_cb_ctx *ctx) {
 gpr_timespec grpc_jwt_verifier_clock_skew = {60, 0, GPR_TIMESPAN};
 
 /* Max delay defaults to one minute. */
-gpr_timespec grpc_jwt_verifier_max_delay = {60, 0, GPR_TIMESPAN};
+grpc_millis grpc_jwt_verifier_max_delay = 60 * GPR_MS_PER_SEC;
 
 typedef struct {
   char *email_domain;
@@ -676,6 +680,7 @@ static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_json *json = json_from_http(response);
   grpc_httpcli_request req;
   const char *jwks_uri;
+  grpc_resource_quota *resource_quota = NULL;
 
   /* TODO(jboeuf): Cache the jwks_uri in order to avoid this hop next time. */
   if (json == NULL) goto error;
@@ -693,9 +698,9 @@ static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
   jwks_uri += 8;
   req.handshaker = &grpc_httpcli_ssl;
   req.host = gpr_strdup(jwks_uri);
-  req.http.path = strchr(jwks_uri, '/');
+  req.http.path = (char *)strchr(jwks_uri, '/');
   if (req.http.path == NULL) {
-    req.http.path = "";
+    req.http.path = (char *)"";
   } else {
     *(req.host + (req.http.path - jwks_uri)) = '\0';
   }
@@ -703,11 +708,10 @@ static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
   /* TODO(ctiller): Carry the resource_quota in ctx and share it with the host
      channel. This would allow us to cancel an authentication query when under
      extreme memory pressure. */
-  grpc_resource_quota *resource_quota =
-      grpc_resource_quota_create("jwt_verifier");
+  resource_quota = grpc_resource_quota_create("jwt_verifier");
   grpc_httpcli_get(
       exec_ctx, &ctx->verifier->http_ctx, &ctx->pollent, resource_quota, &req,
-      gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
+      grpc_exec_ctx_now(exec_ctx) + grpc_jwt_verifier_max_delay,
       GRPC_CLOSURE_CREATE(on_keys_retrieved, ctx, grpc_schedule_on_exec_ctx),
       &ctx->responses[HTTP_RESPONSE_KEYS]);
   grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
@@ -760,7 +764,8 @@ const char *grpc_jwt_issuer_email_domain(const char *issuer) {
   if (dot == NULL || dot == email_domain) return email_domain;
   GPR_ASSERT(dot > email_domain);
   /* There may be a subdomain, we just want the domain. */
-  dot = gpr_memrchr(email_domain, '.', (size_t)(dot - email_domain));
+  dot = (const char *)gpr_memrchr((void *)email_domain, '.',
+                                  (size_t)(dot - email_domain));
   if (dot == NULL) return email_domain;
   return dot + 1;
 }
@@ -773,6 +778,7 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
   char *path_prefix = NULL;
   const char *iss;
   grpc_httpcli_request req;
+  grpc_resource_quota *resource_quota = NULL;
   memset(&req, 0, sizeof(grpc_httpcli_request));
   req.handshaker = &grpc_httpcli_ssl;
   http_response_index rsp_idx;
@@ -831,12 +837,11 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
   /* TODO(ctiller): Carry the resource_quota in ctx and share it with the host
      channel. This would allow us to cancel an authentication query when under
      extreme memory pressure. */
-  grpc_resource_quota *resource_quota =
-      grpc_resource_quota_create("jwt_verifier");
-  grpc_httpcli_get(
-      exec_ctx, &ctx->verifier->http_ctx, &ctx->pollent, resource_quota, &req,
-      gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
-      http_cb, &ctx->responses[rsp_idx]);
+  resource_quota = grpc_resource_quota_create("jwt_verifier");
+  grpc_httpcli_get(exec_ctx, &ctx->verifier->http_ctx, &ctx->pollent,
+                   resource_quota, &req,
+                   grpc_exec_ctx_now(exec_ctx) + grpc_jwt_verifier_max_delay,
+                   http_cb, &ctx->responses[rsp_idx]);
   grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
   gpr_free(req.host);
   gpr_free(req.http.path);
@@ -901,12 +906,14 @@ error:
 grpc_jwt_verifier *grpc_jwt_verifier_create(
     const grpc_jwt_verifier_email_domain_key_url_mapping *mappings,
     size_t num_mappings) {
-  grpc_jwt_verifier *v = gpr_zalloc(sizeof(grpc_jwt_verifier));
+  grpc_jwt_verifier *v =
+      (grpc_jwt_verifier *)gpr_zalloc(sizeof(grpc_jwt_verifier));
   grpc_httpcli_context_init(&v->http_ctx);
 
   /* We know at least of one mapping. */
   v->allocated_mappings = 1 + num_mappings;
-  v->mappings = gpr_malloc(v->allocated_mappings * sizeof(email_key_mapping));
+  v->mappings = (email_key_mapping *)gpr_malloc(v->allocated_mappings *
+                                                sizeof(email_key_mapping));
   verifier_put_mapping(v, GRPC_GOOGLE_SERVICE_ACCOUNTS_EMAIL_DOMAIN,
                        GRPC_GOOGLE_SERVICE_ACCOUNTS_KEY_URL_PREFIX);
   /* User-Provided mappings. */
diff --git a/src/core/lib/security/credentials/jwt/jwt_verifier.h b/src/core/lib/security/credentials/jwt/jwt_verifier.h
index 8fac452d4e..998365e75c 100644
--- a/src/core/lib/security/credentials/jwt/jwt_verifier.h
+++ b/src/core/lib/security/credentials/jwt/jwt_verifier.h
@@ -32,6 +32,10 @@
 #define GRPC_GOOGLE_SERVICE_ACCOUNTS_KEY_URL_PREFIX \
   "www.googleapis.com/robot/v1/metadata/x509"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* --- grpc_jwt_verifier_status. --- */
 
 typedef enum {
@@ -81,7 +85,7 @@ typedef struct {
 
 /* Globals to control the verifier. Not thread-safe. */
 extern gpr_timespec grpc_jwt_verifier_clock_skew;
-extern gpr_timespec grpc_jwt_verifier_max_delay;
+extern grpc_millis grpc_jwt_verifier_max_delay;
 
 /* The verifier can be created with some custom mappings to help with key
    discovery in the case where the issuer is an email address.
@@ -122,4 +126,8 @@ grpc_jwt_verifier_status grpc_jwt_claims_check(const grpc_jwt_claims *claims,
                                                const char *audience);
 const char *grpc_jwt_issuer_email_domain(const char *issuer);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_VERIFIER_H */
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c b/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc
index 10b270c49c..f52a424e36 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc
@@ -117,7 +117,7 @@ static void oauth2_token_fetcher_destruct(grpc_exec_ctx *exec_ctx,
 grpc_credentials_status
 grpc_oauth2_token_fetcher_credentials_parse_server_response(
     grpc_exec_ctx *exec_ctx, const grpc_http_response *response,
-    grpc_mdelem *token_md, gpr_timespec *token_lifetime) {
+    grpc_mdelem *token_md, grpc_millis *token_lifetime) {
   char *null_terminated_body = NULL;
   char *new_access_token = NULL;
   grpc_credentials_status status = GRPC_CREDENTIALS_OK;
@@ -130,7 +130,7 @@ grpc_oauth2_token_fetcher_credentials_parse_server_response(
   }
 
   if (response->body_length > 0) {
-    null_terminated_body = gpr_malloc(response->body_length + 1);
+    null_terminated_body = (char *)gpr_malloc(response->body_length + 1);
     null_terminated_body[response->body_length] = '\0';
     memcpy(null_terminated_body, response->body, response->body_length);
   }
@@ -183,9 +183,7 @@ grpc_oauth2_token_fetcher_credentials_parse_server_response(
     }
     gpr_asprintf(&new_access_token, "%s %s", token_type->value,
                  access_token->value);
-    token_lifetime->tv_sec = strtol(expires_in->value, NULL, 10);
-    token_lifetime->tv_nsec = 0;
-    token_lifetime->clock_type = GPR_TIMESPAN;
+    *token_lifetime = strtol(expires_in->value, NULL, 10) * GPR_MS_PER_SEC;
     if (!GRPC_MDISNULL(*token_md)) GRPC_MDELEM_UNREF(exec_ctx, *token_md);
     *token_md = grpc_mdelem_from_slices(
         exec_ctx,
@@ -214,7 +212,7 @@ static void on_oauth2_token_fetcher_http_response(grpc_exec_ctx *exec_ctx,
   grpc_oauth2_token_fetcher_credentials *c =
       (grpc_oauth2_token_fetcher_credentials *)r->creds;
   grpc_mdelem access_token_md = GRPC_MDNULL;
-  gpr_timespec token_lifetime;
+  grpc_millis token_lifetime;
   grpc_credentials_status status =
       grpc_oauth2_token_fetcher_credentials_parse_server_response(
           exec_ctx, &r->response, &access_token_md, &token_lifetime);
@@ -222,10 +220,9 @@ static void on_oauth2_token_fetcher_http_response(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&c->mu);
   c->token_fetch_pending = false;
   c->access_token_md = GRPC_MDELEM_REF(access_token_md);
-  c->token_expiration =
-      status == GRPC_CREDENTIALS_OK
-          ? gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), token_lifetime)
-          : gpr_inf_past(GPR_CLOCK_REALTIME);
+  c->token_expiration = status == GRPC_CREDENTIALS_OK
+                            ? grpc_exec_ctx_now(exec_ctx) + token_lifetime
+                            : 0;
   grpc_oauth2_pending_get_request_metadata *pending_request =
       c->pending_requests;
   c->pending_requests = NULL;
@@ -260,14 +257,12 @@ static bool oauth2_token_fetcher_get_request_metadata(
   grpc_oauth2_token_fetcher_credentials *c =
       (grpc_oauth2_token_fetcher_credentials *)creds;
   // Check if we can use the cached token.
-  gpr_timespec refresh_threshold = gpr_time_from_seconds(
-      GRPC_SECURE_TOKEN_REFRESH_THRESHOLD_SECS, GPR_TIMESPAN);
+  grpc_millis refresh_threshold =
+      GRPC_SECURE_TOKEN_REFRESH_THRESHOLD_SECS * GPR_MS_PER_SEC;
   grpc_mdelem cached_access_token_md = GRPC_MDNULL;
   gpr_mu_lock(&c->mu);
   if (!GRPC_MDISNULL(c->access_token_md) &&
-      (gpr_time_cmp(
-           gpr_time_sub(c->token_expiration, gpr_now(GPR_CLOCK_REALTIME)),
-           refresh_threshold) > 0)) {
+      (c->token_expiration + grpc_exec_ctx_now(exec_ctx) > refresh_threshold)) {
     cached_access_token_md = GRPC_MDELEM_REF(c->access_token_md);
   }
   if (!GRPC_MDISNULL(cached_access_token_md)) {
@@ -296,10 +291,10 @@ static bool oauth2_token_fetcher_get_request_metadata(
   gpr_mu_unlock(&c->mu);
   if (start_fetch) {
     grpc_call_credentials_ref(creds);
-    c->fetch_func(
-        exec_ctx, grpc_credentials_metadata_request_create(creds),
-        &c->httpcli_context, &c->pollent, on_oauth2_token_fetcher_http_response,
-        gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), refresh_threshold));
+    c->fetch_func(exec_ctx, grpc_credentials_metadata_request_create(creds),
+                  &c->httpcli_context, &c->pollent,
+                  on_oauth2_token_fetcher_http_response,
+                  grpc_exec_ctx_now(exec_ctx) + refresh_threshold);
   }
   return false;
 }
@@ -340,7 +335,7 @@ static void init_oauth2_token_fetcher(grpc_oauth2_token_fetcher_credentials *c,
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_OAUTH2;
   gpr_ref_init(&c->base.refcount, 1);
   gpr_mu_init(&c->mu);
-  c->token_expiration = gpr_inf_past(GPR_CLOCK_REALTIME);
+  c->token_expiration = 0;
   c->fetch_func = fetch_func;
   c->pollent =
       grpc_polling_entity_create_from_pollset_set(grpc_pollset_set_create());
@@ -358,12 +353,12 @@ static grpc_call_credentials_vtable compute_engine_vtable = {
 static void compute_engine_fetch_oauth2(
     grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *metadata_req,
     grpc_httpcli_context *httpcli_context, grpc_polling_entity *pollent,
-    grpc_iomgr_cb_func response_cb, gpr_timespec deadline) {
-  grpc_http_header header = {"Metadata-Flavor", "Google"};
+    grpc_iomgr_cb_func response_cb, grpc_millis deadline) {
+  grpc_http_header header = {(char *)"Metadata-Flavor", (char *)"Google"};
   grpc_httpcli_request request;
   memset(&request, 0, sizeof(grpc_httpcli_request));
-  request.host = GRPC_COMPUTE_ENGINE_METADATA_HOST;
-  request.http.path = GRPC_COMPUTE_ENGINE_METADATA_TOKEN_PATH;
+  request.host = (char *)GRPC_COMPUTE_ENGINE_METADATA_HOST;
+  request.http.path = (char *)GRPC_COMPUTE_ENGINE_METADATA_TOKEN_PATH;
   request.http.hdr_count = 1;
   request.http.hdrs = &header;
   /* TODO(ctiller): Carry the resource_quota in ctx and share it with the host
@@ -381,7 +376,8 @@ static void compute_engine_fetch_oauth2(
 grpc_call_credentials *grpc_google_compute_engine_credentials_create(
     void *reserved) {
   grpc_oauth2_token_fetcher_credentials *c =
-      gpr_malloc(sizeof(grpc_oauth2_token_fetcher_credentials));
+      (grpc_oauth2_token_fetcher_credentials *)gpr_malloc(
+          sizeof(grpc_oauth2_token_fetcher_credentials));
   GRPC_API_TRACE("grpc_compute_engine_credentials_create(reserved=%p)", 1,
                  (reserved));
   GPR_ASSERT(reserved == NULL);
@@ -409,19 +405,19 @@ static grpc_call_credentials_vtable refresh_token_vtable = {
 static void refresh_token_fetch_oauth2(
     grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *metadata_req,
     grpc_httpcli_context *httpcli_context, grpc_polling_entity *pollent,
-    grpc_iomgr_cb_func response_cb, gpr_timespec deadline) {
+    grpc_iomgr_cb_func response_cb, grpc_millis deadline) {
   grpc_google_refresh_token_credentials *c =
       (grpc_google_refresh_token_credentials *)metadata_req->creds;
-  grpc_http_header header = {"Content-Type",
-                             "application/x-www-form-urlencoded"};
+  grpc_http_header header = {(char *)"Content-Type",
+                             (char *)"application/x-www-form-urlencoded"};
   grpc_httpcli_request request;
   char *body = NULL;
   gpr_asprintf(&body, GRPC_REFRESH_TOKEN_POST_BODY_FORMAT_STRING,
                c->refresh_token.client_id, c->refresh_token.client_secret,
                c->refresh_token.refresh_token);
   memset(&request, 0, sizeof(grpc_httpcli_request));
-  request.host = GRPC_GOOGLE_OAUTH2_SERVICE_HOST;
-  request.http.path = GRPC_GOOGLE_OAUTH2_SERVICE_TOKEN_PATH;
+  request.host = (char *)GRPC_GOOGLE_OAUTH2_SERVICE_HOST;
+  request.http.path = (char *)GRPC_GOOGLE_OAUTH2_SERVICE_TOKEN_PATH;
   request.http.hdr_count = 1;
   request.http.hdrs = &header;
   request.handshaker = &grpc_httpcli_ssl;
@@ -447,7 +443,8 @@ grpc_refresh_token_credentials_create_from_auth_refresh_token(
     gpr_log(GPR_ERROR, "Invalid input for refresh token credentials creation");
     return NULL;
   }
-  c = gpr_zalloc(sizeof(grpc_google_refresh_token_credentials));
+  c = (grpc_google_refresh_token_credentials *)gpr_zalloc(
+      sizeof(grpc_google_refresh_token_credentials));
   init_oauth2_token_fetcher(&c->base, refresh_token_fetch_oauth2);
   c->base.base.vtable = &refresh_token_vtable;
   c->refresh_token = refresh_token;
@@ -515,7 +512,8 @@ static grpc_call_credentials_vtable access_token_vtable = {
 grpc_call_credentials *grpc_access_token_credentials_create(
     const char *access_token, void *reserved) {
   grpc_access_token_credentials *c =
-      gpr_zalloc(sizeof(grpc_access_token_credentials));
+      (grpc_access_token_credentials *)gpr_zalloc(
+          sizeof(grpc_access_token_credentials));
   GRPC_API_TRACE(
       "grpc_access_token_credentials_create(access_token=<redacted>, "
       "reserved=%p)",
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
index d9ad6691b8..4beaec93e3 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
@@ -22,6 +22,10 @@
 #include "src/core/lib/json/json.h"
 #include "src/core/lib/security/credentials/credentials.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // auth_refresh_token parsing.
 typedef struct {
   const char *type;
@@ -57,7 +61,7 @@ typedef void (*grpc_fetch_oauth2_func)(grpc_exec_ctx *exec_ctx,
                                        grpc_httpcli_context *http_context,
                                        grpc_polling_entity *pollent,
                                        grpc_iomgr_cb_func cb,
-                                       gpr_timespec deadline);
+                                       grpc_millis deadline);
 
 typedef struct grpc_oauth2_pending_get_request_metadata {
   grpc_credentials_mdelem_array *md_array;
@@ -70,7 +74,7 @@ typedef struct {
   grpc_call_credentials base;
   gpr_mu mu;
   grpc_mdelem access_token_md;
-  gpr_timespec token_expiration;
+  grpc_millis token_expiration;
   bool token_fetch_pending;
   grpc_oauth2_pending_get_request_metadata *pending_requests;
   grpc_httpcli_context httpcli_context;
@@ -100,6 +104,10 @@ grpc_refresh_token_credentials_create_from_auth_refresh_token(
 grpc_credentials_status
 grpc_oauth2_token_fetcher_credentials_parse_server_response(
     grpc_exec_ctx *exec_ctx, const struct grpc_http_response *response,
-    grpc_mdelem *token_md, gpr_timespec *token_lifetime);
+    grpc_mdelem *token_md, grpc_millis *token_lifetime);
+
+#ifdef __cplusplus
+}
+#endif
 
-#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H */
+#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H */
\ No newline at end of file
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.c b/src/core/lib/security/credentials/plugin/plugin_credentials.cc
index 73e0c23e0f..8106a730fe 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.c
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.cc
@@ -31,6 +31,9 @@
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/validate_metadata.h"
 
+grpc_tracer_flag grpc_plugin_credentials_trace =
+    GRPC_TRACER_INITIALIZER(false, "plugin_credentials");
+
 static void plugin_destruct(grpc_exec_ctx *exec_ctx,
                             grpc_call_credentials *creds) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
@@ -53,6 +56,62 @@ static void pending_request_remove_locked(
   }
 }
 
+// Checks if the request has been cancelled.
+// If not, removes it from the pending list, so that it cannot be
+// cancelled out from under us.
+// When this returns, r->cancelled indicates whether the request was
+// cancelled before completion.
+static void pending_request_complete(
+    grpc_exec_ctx *exec_ctx, grpc_plugin_credentials_pending_request *r) {
+  gpr_mu_lock(&r->creds->mu);
+  if (!r->cancelled) pending_request_remove_locked(r->creds, r);
+  gpr_mu_unlock(&r->creds->mu);
+  // Ref to credentials not needed anymore.
+  grpc_call_credentials_unref(exec_ctx, &r->creds->base);
+}
+
+static grpc_error *process_plugin_result(
+    grpc_exec_ctx *exec_ctx, grpc_plugin_credentials_pending_request *r,
+    const grpc_metadata *md, size_t num_md, grpc_status_code status,
+    const char *error_details) {
+  grpc_error *error = GRPC_ERROR_NONE;
+  if (status != GRPC_STATUS_OK) {
+    char *msg;
+    gpr_asprintf(&msg, "Getting metadata from plugin failed with error: %s",
+                 error_details);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
+    gpr_free(msg);
+  } else {
+    bool seen_illegal_header = false;
+    for (size_t i = 0; i < num_md; ++i) {
+      if (!GRPC_LOG_IF_ERROR("validate_metadata_from_plugin",
+                             grpc_validate_header_key_is_legal(md[i].key))) {
+        seen_illegal_header = true;
+        break;
+      } else if (!grpc_is_binary_header(md[i].key) &&
+                 !GRPC_LOG_IF_ERROR(
+                     "validate_metadata_from_plugin",
+                     grpc_validate_header_nonbin_value_is_legal(md[i].value))) {
+        gpr_log(GPR_ERROR, "Plugin added invalid metadata value.");
+        seen_illegal_header = true;
+        break;
+      }
+    }
+    if (seen_illegal_header) {
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Illegal metadata");
+    } else {
+      for (size_t i = 0; i < num_md; ++i) {
+        grpc_mdelem mdelem = grpc_mdelem_from_slices(
+            exec_ctx, grpc_slice_ref_internal(md[i].key),
+            grpc_slice_ref_internal(md[i].value));
+        grpc_credentials_mdelem_array_add(r->md_array, mdelem);
+        GRPC_MDELEM_UNREF(exec_ctx, mdelem);
+      }
+    }
+  }
+  return error;
+}
+
 static void plugin_md_request_metadata_ready(void *request,
                                              const grpc_metadata *md,
                                              size_t num_md,
@@ -64,54 +123,24 @@ static void plugin_md_request_metadata_ready(void *request,
       NULL, NULL);
   grpc_plugin_credentials_pending_request *r =
       (grpc_plugin_credentials_pending_request *)request;
-  // Check if the request has been cancelled.
-  // If not, remove it from the pending list, so that it cannot be
-  // cancelled out from under us.
-  gpr_mu_lock(&r->creds->mu);
-  if (!r->cancelled) pending_request_remove_locked(r->creds, r);
-  gpr_mu_unlock(&r->creds->mu);
-  grpc_call_credentials_unref(&exec_ctx, &r->creds->base);
+  if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+    gpr_log(GPR_INFO,
+            "plugin_credentials[%p]: request %p: plugin returned "
+            "asynchronously",
+            r->creds, r);
+  }
+  // Remove request from pending list if not previously cancelled.
+  pending_request_complete(&exec_ctx, r);
   // If it has not been cancelled, process it.
   if (!r->cancelled) {
-    if (status != GRPC_STATUS_OK) {
-      char *msg;
-      gpr_asprintf(&msg, "Getting metadata from plugin failed with error: %s",
-                   error_details);
-      GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata,
-                         GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg));
-      gpr_free(msg);
-    } else {
-      bool seen_illegal_header = false;
-      for (size_t i = 0; i < num_md; ++i) {
-        if (!GRPC_LOG_IF_ERROR("validate_metadata_from_plugin",
-                               grpc_validate_header_key_is_legal(md[i].key))) {
-          seen_illegal_header = true;
-          break;
-        } else if (!grpc_is_binary_header(md[i].key) &&
-                   !GRPC_LOG_IF_ERROR(
-                       "validate_metadata_from_plugin",
-                       grpc_validate_header_nonbin_value_is_legal(
-                           md[i].value))) {
-          gpr_log(GPR_ERROR, "Plugin added invalid metadata value.");
-          seen_illegal_header = true;
-          break;
-        }
-      }
-      if (seen_illegal_header) {
-        GRPC_CLOSURE_SCHED(
-            &exec_ctx, r->on_request_metadata,
-            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Illegal metadata"));
-      } else {
-        for (size_t i = 0; i < num_md; ++i) {
-          grpc_mdelem mdelem = grpc_mdelem_from_slices(
-              &exec_ctx, grpc_slice_ref_internal(md[i].key),
-              grpc_slice_ref_internal(md[i].value));
-          grpc_credentials_mdelem_array_add(r->md_array, mdelem);
-          GRPC_MDELEM_UNREF(&exec_ctx, mdelem);
-        }
-        GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata, GRPC_ERROR_NONE);
-      }
-    }
+    grpc_error *error =
+        process_plugin_result(&exec_ctx, r, md, num_md, status, error_details);
+    GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata, error);
+  } else if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+    gpr_log(GPR_INFO,
+            "plugin_credentials[%p]: request %p: plugin was previously "
+            "cancelled",
+            r->creds, r);
   }
   gpr_free(r);
   grpc_exec_ctx_finish(&exec_ctx);
@@ -125,6 +154,7 @@ static bool plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                         grpc_closure *on_request_metadata,
                                         grpc_error **error) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
+  bool retval = true;  // Synchronous return.
   if (c->plugin.get_metadata != NULL) {
     // Create pending_request object.
     grpc_plugin_credentials_pending_request *pending_request =
@@ -142,12 +172,60 @@ static bool plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
     c->pending_requests = pending_request;
     gpr_mu_unlock(&c->mu);
     // Invoke the plugin.  The callback holds a ref to us.
+    if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+      gpr_log(GPR_INFO, "plugin_credentials[%p]: request %p: invoking plugin",
+              c, pending_request);
+    }
     grpc_call_credentials_ref(creds);
-    c->plugin.get_metadata(c->plugin.state, context,
-                           plugin_md_request_metadata_ready, pending_request);
-    return false;
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX];
+    size_t num_creds_md = 0;
+    grpc_status_code status = GRPC_STATUS_OK;
+    const char *error_details = NULL;
+    if (!c->plugin.get_metadata(c->plugin.state, context,
+                                plugin_md_request_metadata_ready,
+                                pending_request, creds_md, &num_creds_md,
+                                &status, &error_details)) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p: plugin will return "
+                "asynchronously",
+                c, pending_request);
+      }
+      return false;  // Asynchronous return.
+    }
+    // Returned synchronously.
+    // Remove request from pending list if not previously cancelled.
+    pending_request_complete(exec_ctx, pending_request);
+    // If the request was cancelled, the error will have been returned
+    // asynchronously by plugin_cancel_get_request_metadata(), so return
+    // false.  Otherwise, process the result.
+    if (pending_request->cancelled) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p was cancelled, error "
+                "will be returned asynchronously",
+                c, pending_request);
+      }
+      retval = false;
+    } else {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p: plugin returned "
+                "synchronously",
+                c, pending_request);
+      }
+      *error = process_plugin_result(exec_ctx, pending_request, creds_md,
+                                     num_creds_md, status, error_details);
+    }
+    // Clean up.
+    for (size_t i = 0; i < num_creds_md; ++i) {
+      grpc_slice_unref_internal(exec_ctx, creds_md[i].key);
+      grpc_slice_unref_internal(exec_ctx, creds_md[i].value);
+    }
+    gpr_free((void *)error_details);
+    gpr_free(pending_request);
   }
-  return true;
+  return retval;
 }
 
 static void plugin_cancel_get_request_metadata(
@@ -159,6 +237,10 @@ static void plugin_cancel_get_request_metadata(
            c->pending_requests;
        pending_request != NULL; pending_request = pending_request->next) {
     if (pending_request->md_array == md_array) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO, "plugin_credentials[%p]: cancelling request %p", c,
+                pending_request);
+      }
       pending_request->cancelled = true;
       GRPC_CLOSURE_SCHED(exec_ctx, pending_request->on_request_metadata,
                          GRPC_ERROR_REF(error));
@@ -176,7 +258,8 @@ static grpc_call_credentials_vtable plugin_vtable = {
 
 grpc_call_credentials *grpc_metadata_credentials_create_from_plugin(
     grpc_metadata_credentials_plugin plugin, void *reserved) {
-  grpc_plugin_credentials *c = gpr_zalloc(sizeof(*c));
+  grpc_plugin_credentials *c =
+      (grpc_plugin_credentials *)gpr_zalloc(sizeof(*c));
   GRPC_API_TRACE("grpc_metadata_credentials_create_from_plugin(reserved=%p)", 1,
                  (reserved));
   GPR_ASSERT(reserved == NULL);
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.h b/src/core/lib/security/credentials/plugin/plugin_credentials.h
index 57266d589a..f56df9eac5 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.h
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.h
@@ -21,6 +21,8 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+extern grpc_tracer_flag grpc_plugin_credentials_trace;
+
 struct grpc_plugin_credentials;
 
 typedef struct grpc_plugin_credentials_pending_request {
diff --git a/src/core/lib/security/credentials/ssl/ssl_credentials.c b/src/core/lib/security/credentials/ssl/ssl_credentials.cc
index 006db1ec76..9df69a2a3d 100644
--- a/src/core/lib/security/credentials/ssl/ssl_credentials.c
+++ b/src/core/lib/security/credentials/ssl/ssl_credentials.cc
@@ -66,8 +66,8 @@ static grpc_security_status ssl_create_security_connector(
   if (status != GRPC_SECURITY_OK) {
     return status;
   }
-  grpc_arg new_arg =
-      grpc_channel_arg_string_create(GRPC_ARG_HTTP2_SCHEME, "https");
+  grpc_arg new_arg = grpc_channel_arg_string_create(
+      (char *)GRPC_ARG_HTTP2_SCHEME, (char *)"https");
   *new_args = grpc_channel_args_copy_and_add(args, &new_arg, 1);
   return status;
 }
@@ -94,7 +94,8 @@ static void ssl_build_config(const char *pem_root_certs,
 grpc_channel_credentials *grpc_ssl_credentials_create(
     const char *pem_root_certs, grpc_ssl_pem_key_cert_pair *pem_key_cert_pair,
     void *reserved) {
-  grpc_ssl_credentials *c = gpr_zalloc(sizeof(grpc_ssl_credentials));
+  grpc_ssl_credentials *c =
+      (grpc_ssl_credentials *)gpr_zalloc(sizeof(grpc_ssl_credentials));
   GRPC_API_TRACE(
       "grpc_ssl_credentials_create(pem_root_certs=%s, "
       "pem_key_cert_pair=%p, "
@@ -145,8 +146,8 @@ static void ssl_build_server_config(
   }
   if (num_key_cert_pairs > 0) {
     GPR_ASSERT(pem_key_cert_pairs != NULL);
-    config->pem_key_cert_pairs =
-        gpr_zalloc(num_key_cert_pairs * sizeof(tsi_ssl_pem_key_cert_pair));
+    config->pem_key_cert_pairs = (tsi_ssl_pem_key_cert_pair *)gpr_zalloc(
+        num_key_cert_pairs * sizeof(tsi_ssl_pem_key_cert_pair));
   }
   config->num_key_cert_pairs = num_key_cert_pairs;
   for (i = 0; i < num_key_cert_pairs; i++) {
@@ -175,8 +176,8 @@ grpc_server_credentials *grpc_ssl_server_credentials_create_ex(
     size_t num_key_cert_pairs,
     grpc_ssl_client_certificate_request_type client_certificate_request,
     void *reserved) {
-  grpc_ssl_server_credentials *c =
-      gpr_zalloc(sizeof(grpc_ssl_server_credentials));
+  grpc_ssl_server_credentials *c = (grpc_ssl_server_credentials *)gpr_zalloc(
+      sizeof(grpc_ssl_server_credentials));
   GRPC_API_TRACE(
       "grpc_ssl_server_credentials_create_ex("
       "pem_root_certs=%s, pem_key_cert_pairs=%p, num_key_cert_pairs=%lu, "
diff --git a/src/core/lib/security/transport/auth_filters.h b/src/core/lib/security/transport/auth_filters.h
index bd5902a128..ba5df7fe70 100644
--- a/src/core/lib/security/transport/auth_filters.h
+++ b/src/core/lib/security/transport/auth_filters.h
@@ -21,7 +21,15 @@
 
 #include "src/core/lib/channel/channel_stack.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_client_auth_filter;
 extern const grpc_channel_filter grpc_server_auth_filter;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_AUTH_FILTERS_H */
diff --git a/src/core/lib/security/transport/client_auth_filter.c b/src/core/lib/security/transport/client_auth_filter.cc
index dd7dd44e79..a8464dbf9e 100644
--- a/src/core/lib/security/transport/client_auth_filter.c
+++ b/src/core/lib/security/transport/client_auth_filter.cc
@@ -93,8 +93,9 @@ static void add_error(grpc_error **combined, grpc_error *error) {
 static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *arg,
                                     grpc_error *input_error) {
   grpc_transport_stream_op_batch *batch = (grpc_transport_stream_op_batch *)arg;
-  grpc_call_element *elem = batch->handler_private.extra_arg;
-  call_data *calld = elem->call_data;
+  grpc_call_element *elem =
+      (grpc_call_element *)batch->handler_private.extra_arg;
+  call_data *calld = (call_data *)elem->call_data;
   reset_auth_metadata_context(&calld->auth_md_context);
   grpc_error *error = GRPC_ERROR_REF(input_error);
   if (error == GRPC_ERROR_NONE) {
@@ -163,8 +164,8 @@ static void cancel_get_request_metadata(grpc_exec_ctx *exec_ctx, void *arg,
 static void send_security_metadata(grpc_exec_ctx *exec_ctx,
                                    grpc_call_element *elem,
                                    grpc_transport_stream_op_batch *batch) {
-  call_data *calld = elem->call_data;
-  channel_data *chand = elem->channel_data;
+  call_data *calld = (call_data *)elem->call_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
   grpc_client_security_context *ctx =
       (grpc_client_security_context *)batch->payload
           ->context[GRPC_CONTEXT_SECURITY]
@@ -225,8 +226,9 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
 static void on_host_checked(grpc_exec_ctx *exec_ctx, void *arg,
                             grpc_error *error) {
   grpc_transport_stream_op_batch *batch = (grpc_transport_stream_op_batch *)arg;
-  grpc_call_element *elem = batch->handler_private.extra_arg;
-  call_data *calld = elem->call_data;
+  grpc_call_element *elem =
+      (grpc_call_element *)batch->handler_private.extra_arg;
+  call_data *calld = (call_data *)elem->call_data;
   if (error == GRPC_ERROR_NONE) {
     send_security_metadata(exec_ctx, elem, batch);
   } else {
@@ -264,8 +266,8 @@ static void auth_start_transport_stream_op_batch(
   GPR_TIMER_BEGIN("auth_start_transport_stream_op_batch", 0);
 
   /* grab pointers to our data from the call element */
-  call_data *calld = elem->call_data;
-  channel_data *chand = elem->channel_data;
+  call_data *calld = (call_data *)elem->call_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
 
   if (!batch->cancel_stream) {
     GPR_ASSERT(batch->payload->context != NULL);
@@ -276,7 +278,9 @@ static void auth_start_transport_stream_op_batch(
           grpc_client_security_context_destroy;
     }
     grpc_client_security_context *sec_ctx =
-        batch->payload->context[GRPC_CONTEXT_SECURITY].value;
+        (grpc_client_security_context *)batch->payload
+            ->context[GRPC_CONTEXT_SECURITY]
+            .value;
     GRPC_AUTH_CONTEXT_UNREF(sec_ctx->auth_context, "client auth filter");
     sec_ctx->auth_context =
         GRPC_AUTH_CONTEXT_REF(chand->auth_context, "client_auth_filter");
@@ -339,7 +343,7 @@ static void auth_start_transport_stream_op_batch(
 static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
                                   grpc_call_element *elem,
                                   const grpc_call_element_args *args) {
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   calld->owning_call = args->call_stack;
   calld->call_combiner = args->call_combiner;
   return GRPC_ERROR_NONE;
@@ -348,7 +352,7 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
 static void set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
                                        grpc_call_element *elem,
                                        grpc_polling_entity *pollent) {
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   calld->pollent = pollent;
 }
 
@@ -356,7 +360,7 @@ static void set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx,
 static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               const grpc_call_final_info *final_info,
                               grpc_closure *ignored) {
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   grpc_credentials_mdelem_array_destroy(exec_ctx, &calld->md_array);
   grpc_call_credentials_unref(exec_ctx, calld->creds);
   if (calld->have_host) {
@@ -386,7 +390,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
   }
 
   /* grab pointers to our data from the channel element */
-  channel_data *chand = elem->channel_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
 
   /* The first and the last filters tend to be implemented differently to
      handle the case that there's no 'next' filter to call on the up or down
@@ -406,7 +410,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
   /* grab pointers to our data from the channel element */
-  channel_data *chand = elem->channel_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
   grpc_channel_security_connector *sc = chand->security_connector;
   if (sc != NULL) {
     GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, &sc->base, "client_auth_filter");
diff --git a/src/core/lib/security/transport/lb_targets_info.c b/src/core/lib/security/transport/lb_targets_info.cc
index 5583a4e0ff..947fc1addf 100644
--- a/src/core/lib/security/transport/lb_targets_info.c
+++ b/src/core/lib/security/transport/lb_targets_info.cc
@@ -25,19 +25,22 @@
  * secure naming purposes. */
 #define GRPC_ARG_LB_SECURE_NAMING_MAP "grpc.lb_secure_naming_map"
 
-static void *targets_info_copy(void *p) { return grpc_slice_hash_table_ref(p); }
+static void *targets_info_copy(void *p) {
+  return grpc_slice_hash_table_ref((grpc_slice_hash_table *)p);
+}
 static void targets_info_destroy(grpc_exec_ctx *exec_ctx, void *p) {
-  grpc_slice_hash_table_unref(exec_ctx, p);
+  grpc_slice_hash_table_unref(exec_ctx, (grpc_slice_hash_table *)p);
 }
 static int targets_info_cmp(void *a, void *b) {
-  return grpc_slice_hash_table_cmp(a, b);
+  return grpc_slice_hash_table_cmp((const grpc_slice_hash_table *)a,
+                                   (const grpc_slice_hash_table *)b);
 }
 static const grpc_arg_pointer_vtable server_to_balancer_names_vtable = {
     targets_info_copy, targets_info_destroy, targets_info_cmp};
 
 grpc_arg grpc_lb_targets_info_create_channel_arg(
     grpc_slice_hash_table *targets_info) {
-  return grpc_channel_arg_pointer_create(GRPC_ARG_LB_SECURE_NAMING_MAP,
+  return grpc_channel_arg_pointer_create((char *)GRPC_ARG_LB_SECURE_NAMING_MAP,
                                          targets_info,
                                          &server_to_balancer_names_vtable);
 }
@@ -48,7 +51,7 @@ grpc_slice_hash_table *grpc_lb_targets_info_find_in_args(
       grpc_channel_args_find(args, GRPC_ARG_LB_SECURE_NAMING_MAP);
   if (targets_info_arg != NULL) {
     GPR_ASSERT(targets_info_arg->type == GRPC_ARG_POINTER);
-    return targets_info_arg->value.pointer.p;
+    return (grpc_slice_hash_table *)targets_info_arg->value.pointer.p;
   }
   return NULL;
 }
diff --git a/src/core/lib/security/transport/lb_targets_info.h b/src/core/lib/security/transport/lb_targets_info.h
index c3d685df5f..705d33b0ab 100644
--- a/src/core/lib/security/transport/lb_targets_info.h
+++ b/src/core/lib/security/transport/lb_targets_info.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/slice/slice_hash_table.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** Return a channel argument containing \a targets_info. */
 grpc_arg grpc_lb_targets_info_create_channel_arg(
     grpc_slice_hash_table *targets_info);
@@ -29,4 +33,8 @@ grpc_arg grpc_lb_targets_info_create_channel_arg(
 grpc_slice_hash_table *grpc_lb_targets_info_find_in_args(
     const grpc_channel_args *args);
 
-#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_LB_TARGETS_INFO_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_LB_TARGETS_INFO_H */
\ No newline at end of file
diff --git a/src/core/lib/security/transport/secure_endpoint.c b/src/core/lib/security/transport/secure_endpoint.cc
index ae5633b82c..ae5633b82c 100644
--- a/src/core/lib/security/transport/secure_endpoint.c
+++ b/src/core/lib/security/transport/secure_endpoint.cc
diff --git a/src/core/lib/security/transport/secure_endpoint.h b/src/core/lib/security/transport/secure_endpoint.h
index 3323a6ff42..832cc1c0ce 100644
--- a/src/core/lib/security/transport/secure_endpoint.h
+++ b/src/core/lib/security/transport/secure_endpoint.h
@@ -22,6 +22,10 @@
 #include <grpc/slice.h>
 #include "src/core/lib/iomgr/endpoint.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct tsi_frame_protector;
 struct tsi_zero_copy_grpc_protector;
 
@@ -36,4 +40,8 @@ grpc_endpoint *grpc_secure_endpoint_create(
     grpc_endpoint *to_wrap, grpc_slice *leftover_slices,
     size_t leftover_nslices);
 
-#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURE_ENDPOINT_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURE_ENDPOINT_H */
\ No newline at end of file
diff --git a/src/core/lib/security/transport/security_connector.c b/src/core/lib/security/transport/security_connector.cc
index 2a9e939d40..51844fb91f 100644
--- a/src/core/lib/security/transport/security_connector.c
+++ b/src/core/lib/security/transport/security_connector.cc
@@ -200,11 +200,13 @@ void grpc_security_connector_unref(grpc_exec_ctx *exec_ctx,
 }
 
 static void connector_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
-  GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, p, "connector_pointer_arg_destroy");
+  GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, (grpc_security_connector *)p,
+                                "connector_pointer_arg_destroy");
 }
 
 static void *connector_pointer_arg_copy(void *p) {
-  return GRPC_SECURITY_CONNECTOR_REF(p, "connector_pointer_arg_copy");
+  return GRPC_SECURITY_CONNECTOR_REF((grpc_security_connector *)p,
+                                     "connector_pointer_arg_copy");
 }
 
 static int connector_pointer_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
@@ -214,8 +216,8 @@ static const grpc_arg_pointer_vtable connector_pointer_vtable = {
     connector_pointer_cmp};
 
 grpc_arg grpc_security_connector_to_arg(grpc_security_connector *sc) {
-  return grpc_channel_arg_pointer_create(GRPC_ARG_SECURITY_CONNECTOR, sc,
-                                         &connector_pointer_vtable);
+  return grpc_channel_arg_pointer_create((char *)GRPC_ARG_SECURITY_CONNECTOR,
+                                         sc, &connector_pointer_vtable);
 }
 
 grpc_security_connector *grpc_security_connector_from_arg(const grpc_arg *arg) {
@@ -225,7 +227,7 @@ grpc_security_connector *grpc_security_connector_from_arg(const grpc_arg *arg) {
             GRPC_ARG_SECURITY_CONNECTOR);
     return NULL;
   }
-  return arg->value.pointer.p;
+  return (grpc_security_connector *)arg->value.pointer.p;
 }
 
 grpc_security_connector *grpc_security_connector_find_in_args(
@@ -424,7 +426,8 @@ static grpc_security_connector_vtable fake_server_vtable = {
 grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
     grpc_call_credentials *request_metadata_creds, const char *target,
     const grpc_channel_args *args) {
-  grpc_fake_channel_security_connector *c = gpr_zalloc(sizeof(*c));
+  grpc_fake_channel_security_connector *c =
+      (grpc_fake_channel_security_connector *)gpr_zalloc(sizeof(*c));
   gpr_ref_init(&c->base.base.refcount, 1);
   c->base.base.url_scheme = GRPC_FAKE_SECURITY_URL_SCHEME;
   c->base.base.vtable = &fake_channel_vtable;
@@ -443,7 +446,8 @@ grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
 grpc_server_security_connector *grpc_fake_server_security_connector_create(
     void) {
   grpc_server_security_connector *c =
-      gpr_zalloc(sizeof(grpc_server_security_connector));
+      (grpc_server_security_connector *)gpr_zalloc(
+          sizeof(grpc_server_security_connector));
   gpr_ref_init(&c->base.refcount, 1);
   c->base.vtable = &fake_server_vtable;
   c->base.url_scheme = GRPC_FAKE_SECURITY_URL_SCHEME;
@@ -658,7 +662,8 @@ tsi_peer tsi_shallow_peer_from_ssl_auth_context(
   while (grpc_auth_property_iterator_next(&it) != NULL) max_num_props++;
 
   if (max_num_props > 0) {
-    peer.properties = gpr_malloc(max_num_props * sizeof(tsi_peer_property));
+    peer.properties = (tsi_peer_property *)gpr_malloc(
+        max_num_props * sizeof(tsi_peer_property));
     it = grpc_auth_context_property_iterator(auth_context);
     while ((prop = grpc_auth_property_iterator_next(&it)) != NULL) {
       if (strcmp(prop->name, GRPC_X509_SAN_PROPERTY_NAME) == 0) {
@@ -804,13 +809,13 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
     const char *overridden_target_name, grpc_channel_security_connector **sc) {
   size_t num_alpn_protocols = grpc_chttp2_num_alpn_versions();
   const char **alpn_protocol_strings =
-      gpr_malloc(sizeof(const char *) * num_alpn_protocols);
+      (const char **)gpr_malloc(sizeof(const char *) * num_alpn_protocols);
   tsi_result result = TSI_OK;
   grpc_ssl_channel_security_connector *c;
   size_t i;
   const char *pem_root_certs;
   char *port;
-
+  bool has_key_cert_pair;
   for (i = 0; i < num_alpn_protocols; i++) {
     alpn_protocol_strings[i] = grpc_chttp2_get_alpn_version_index(i);
   }
@@ -829,7 +834,8 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
     pem_root_certs = config->pem_root_certs;
   }
 
-  c = gpr_zalloc(sizeof(grpc_ssl_channel_security_connector));
+  c = (grpc_ssl_channel_security_connector *)gpr_zalloc(
+      sizeof(grpc_ssl_channel_security_connector));
 
   gpr_ref_init(&c->base.base.refcount, 1);
   c->base.base.vtable = &ssl_channel_vtable;
@@ -845,8 +851,8 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
     c->overridden_target_name = gpr_strdup(overridden_target_name);
   }
 
-  bool has_key_cert_pair = config->pem_key_cert_pair.private_key != NULL &&
-                           config->pem_key_cert_pair.cert_chain != NULL;
+  has_key_cert_pair = config->pem_key_cert_pair.private_key != NULL &&
+                      config->pem_key_cert_pair.cert_chain != NULL;
   result = tsi_create_ssl_client_handshaker_factory(
       has_key_cert_pair ? &config->pem_key_cert_pair : NULL, pem_root_certs,
       ssl_cipher_suites(), alpn_protocol_strings, (uint16_t)num_alpn_protocols,
@@ -872,7 +878,7 @@ grpc_security_status grpc_ssl_server_security_connector_create(
     grpc_server_security_connector **sc) {
   size_t num_alpn_protocols = grpc_chttp2_num_alpn_versions();
   const char **alpn_protocol_strings =
-      gpr_malloc(sizeof(const char *) * num_alpn_protocols);
+      (const char **)gpr_malloc(sizeof(const char *) * num_alpn_protocols);
   tsi_result result = TSI_OK;
   grpc_ssl_server_security_connector *c;
   size_t i;
@@ -885,7 +891,8 @@ grpc_security_status grpc_ssl_server_security_connector_create(
     gpr_log(GPR_ERROR, "An SSL server needs a key and a cert.");
     goto error;
   }
-  c = gpr_zalloc(sizeof(grpc_ssl_server_security_connector));
+  c = (grpc_ssl_server_security_connector *)gpr_zalloc(
+      sizeof(grpc_ssl_server_security_connector));
 
   gpr_ref_init(&c->base.base.refcount, 1);
   c->base.base.url_scheme = GRPC_SSL_URL_SCHEME;
diff --git a/src/core/lib/security/transport/security_connector.h b/src/core/lib/security/transport/security_connector.h
index 4f9b63ad20..4d87cd0c80 100644
--- a/src/core/lib/security/transport/security_connector.h
+++ b/src/core/lib/security/transport/security_connector.h
@@ -29,6 +29,10 @@
 #include "src/core/tsi/ssl_transport_security.h"
 #include "src/core/tsi/transport_security_interface.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef NDEBUG
 extern grpc_tracer_flag grpc_trace_security_connector_refcount;
 #endif
@@ -245,4 +249,8 @@ tsi_peer tsi_shallow_peer_from_ssl_auth_context(
     const grpc_auth_context *auth_context);
 void tsi_shallow_peer_destruct(tsi_peer *peer);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_CONNECTOR_H */
diff --git a/src/core/lib/security/transport/security_handshaker.c b/src/core/lib/security/transport/security_handshaker.cc
index 3d19605617..3d19605617 100644
--- a/src/core/lib/security/transport/security_handshaker.c
+++ b/src/core/lib/security/transport/security_handshaker.cc
diff --git a/src/core/lib/security/transport/security_handshaker.h b/src/core/lib/security/transport/security_handshaker.h
index 95bf127fc6..345065f26c 100644
--- a/src/core/lib/security/transport/security_handshaker.h
+++ b/src/core/lib/security/transport/security_handshaker.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/security/transport/security_connector.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /// Creates a security handshaker using \a handshaker.
 grpc_handshaker *grpc_security_handshaker_create(
     grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
@@ -31,4 +35,8 @@ grpc_handshaker *grpc_security_handshaker_create(
 /// Registers security handshaker factories.
 void grpc_security_register_handshaker_factories();
 
-#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_HANDSHAKER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_HANDSHAKER_H */
\ No newline at end of file
diff --git a/src/core/lib/security/transport/server_auth_filter.c b/src/core/lib/security/transport/server_auth_filter.cc
index 7f523c0883..f5e02f42fe 100644
--- a/src/core/lib/security/transport/server_auth_filter.c
+++ b/src/core/lib/security/transport/server_auth_filter.cc
@@ -63,8 +63,8 @@ static grpc_metadata_array metadata_batch_to_md_array(
     grpc_slice value = GRPC_MDVALUE(md);
     if (result.count == result.capacity) {
       result.capacity = GPR_MAX(result.capacity + 8, result.capacity * 2);
-      result.metadata =
-          gpr_realloc(result.metadata, result.capacity * sizeof(grpc_metadata));
+      result.metadata = (grpc_metadata *)gpr_realloc(
+          result.metadata, result.capacity * sizeof(grpc_metadata));
     }
     usr_md = &result.metadata[result.count++];
     usr_md->key = grpc_slice_ref_internal(key);
@@ -76,8 +76,8 @@ static grpc_metadata_array metadata_batch_to_md_array(
 static grpc_filtered_mdelem remove_consumed_md(grpc_exec_ctx *exec_ctx,
                                                void *user_data,
                                                grpc_mdelem md) {
-  grpc_call_element *elem = user_data;
-  call_data *calld = elem->call_data;
+  grpc_call_element *elem = (grpc_call_element *)user_data;
+  call_data *calld = (call_data *)elem->call_data;
   size_t i;
   for (i = 0; i < calld->num_consumed_md; i++) {
     const grpc_metadata *consumed_md = &calld->consumed_md[i];
@@ -95,7 +95,7 @@ static void on_md_processing_done_inner(grpc_exec_ctx *exec_ctx,
                                         const grpc_metadata *response_md,
                                         size_t num_response_md,
                                         grpc_error *error) {
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   grpc_transport_stream_op_batch *batch = calld->recv_initial_metadata_batch;
   /* TODO(jboeuf): Implement support for response_md. */
   if (response_md != NULL && num_response_md > 0) {
@@ -119,8 +119,8 @@ static void on_md_processing_done(
     void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
     const grpc_metadata *response_md, size_t num_response_md,
     grpc_status_code status, const char *error_details) {
-  grpc_call_element *elem = user_data;
-  call_data *calld = elem->call_data;
+  grpc_call_element *elem = (grpc_call_element *)user_data;
+  call_data *calld = (call_data *)elem->call_data;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   // If the call was not cancelled while we were in flight, process the result.
   if (gpr_atm_full_cas(&calld->state, (gpr_atm)STATE_INIT,
@@ -149,7 +149,7 @@ static void on_md_processing_done(
 
 static void cancel_call(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   grpc_call_element *elem = (grpc_call_element *)arg;
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   // If the result was not already processed, invoke the callback now.
   if (error != GRPC_ERROR_NONE &&
       gpr_atm_full_cas(&calld->state, (gpr_atm)STATE_INIT,
@@ -163,8 +163,8 @@ static void cancel_call(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
 static void recv_initial_metadata_ready(grpc_exec_ctx *exec_ctx, void *arg,
                                         grpc_error *error) {
   grpc_call_element *elem = (grpc_call_element *)arg;
-  channel_data *chand = elem->channel_data;
-  call_data *calld = elem->call_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
+  call_data *calld = (call_data *)elem->call_data;
   grpc_transport_stream_op_batch *batch = calld->recv_initial_metadata_batch;
   if (error == GRPC_ERROR_NONE) {
     if (chand->creds != NULL && chand->creds->processor.process != NULL) {
@@ -191,7 +191,7 @@ static void recv_initial_metadata_ready(grpc_exec_ctx *exec_ctx, void *arg,
 static void auth_start_transport_stream_op_batch(
     grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     grpc_transport_stream_op_batch *batch) {
-  call_data *calld = elem->call_data;
+  call_data *calld = (call_data *)elem->call_data;
   if (batch->recv_initial_metadata) {
     // Inject our callback.
     calld->recv_initial_metadata_batch = batch;
@@ -207,8 +207,8 @@ static void auth_start_transport_stream_op_batch(
 static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
                                   grpc_call_element *elem,
                                   const grpc_call_element_args *args) {
-  call_data *calld = elem->call_data;
-  channel_data *chand = elem->channel_data;
+  call_data *calld = (call_data *)elem->call_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
   calld->call_combiner = args->call_combiner;
   calld->owning_call = args->call_stack;
   GRPC_CLOSURE_INIT(&calld->recv_initial_metadata_ready,
@@ -240,7 +240,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
                                      grpc_channel_element *elem,
                                      grpc_channel_element_args *args) {
   GPR_ASSERT(!args->is_last);
-  channel_data *chand = elem->channel_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
   grpc_auth_context *auth_context =
       grpc_find_auth_context_in_args(args->channel_args);
   GPR_ASSERT(auth_context != NULL);
@@ -255,7 +255,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
 /* Destructor for channel data */
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
-  channel_data *chand = elem->channel_data;
+  channel_data *chand = (channel_data *)elem->channel_data;
   GRPC_AUTH_CONTEXT_UNREF(chand->auth_context, "server_auth_filter");
   grpc_server_credentials_unref(exec_ctx, chand->creds);
 }
diff --git a/src/core/lib/security/transport/tsi_error.c b/src/core/lib/security/transport/tsi_error.cc
index 72f9600e84..72f9600e84 100644
--- a/src/core/lib/security/transport/tsi_error.c
+++ b/src/core/lib/security/transport/tsi_error.cc
diff --git a/src/core/lib/security/transport/tsi_error.h b/src/core/lib/security/transport/tsi_error.h
index 87a63a8a7c..4c78b06603 100644
--- a/src/core/lib/security/transport/tsi_error.h
+++ b/src/core/lib/security/transport/tsi_error.h
@@ -22,6 +22,14 @@
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/tsi/transport_security_interface.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_error *grpc_set_tsi_error_result(grpc_error *error, tsi_result result);
 
-#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_TSI_ERROR_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_TSI_ERROR_H */
\ No newline at end of file
diff --git a/src/core/lib/security/util/json_util.c b/src/core/lib/security/util/json_util.cc
index d847addef9..d847addef9 100644
--- a/src/core/lib/security/util/json_util.c
+++ b/src/core/lib/security/util/json_util.cc
diff --git a/src/core/lib/security/util/json_util.h b/src/core/lib/security/util/json_util.h
index 5ea831e27e..43a2f6b9d1 100644
--- a/src/core/lib/security/util/json_util.h
+++ b/src/core/lib/security/util/json_util.h
@@ -28,6 +28,10 @@
 #define GRPC_AUTH_JSON_TYPE_SERVICE_ACCOUNT "service_account"
 #define GRPC_AUTH_JSON_TYPE_AUTHORIZED_USER "authorized_user"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Gets a child property from a json node.
 const char *grpc_json_get_string_property(const grpc_json *json,
                                           const char *prop_name);
@@ -37,4 +41,8 @@ const char *grpc_json_get_string_property(const grpc_json *json,
 bool grpc_copy_json_string_property(const grpc_json *json,
                                     const char *prop_name, char **copied_value);
 
-#endif /* GRPC_CORE_LIB_SECURITY_UTIL_JSON_UTIL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SECURITY_UTIL_JSON_UTIL_H */
\ No newline at end of file
diff --git a/src/core/lib/slice/b64.c b/src/core/lib/slice/b64.cc
index 50264719a4..50264719a4 100644
--- a/src/core/lib/slice/b64.c
+++ b/src/core/lib/slice/b64.cc
diff --git a/src/core/lib/slice/b64.h b/src/core/lib/slice/b64.h
index 3fd15febe5..c01da56575 100644
--- a/src/core/lib/slice/b64.h
+++ b/src/core/lib/slice/b64.h
@@ -21,6 +21,10 @@
 
 #include <grpc/slice.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Encodes data using base64. It is the caller's responsability to free
    the returned char * using gpr_free. Returns NULL on NULL input.
    TODO(makdharma) : change the flags to bool from int */
@@ -47,4 +51,8 @@ grpc_slice grpc_base64_decode(grpc_exec_ctx *exec_ctx, const char *b64,
 grpc_slice grpc_base64_decode_with_len(grpc_exec_ctx *exec_ctx, const char *b64,
                                        size_t b64_len, int url_safe);
 
-#endif /* GRPC_CORE_LIB_SLICE_B64_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SLICE_B64_H */
\ No newline at end of file
diff --git a/src/core/lib/slice/percent_encoding.c b/src/core/lib/slice/percent_encoding.cc
index effc8d7ad6..effc8d7ad6 100644
--- a/src/core/lib/slice/percent_encoding.c
+++ b/src/core/lib/slice/percent_encoding.cc
diff --git a/src/core/lib/slice/percent_encoding.h b/src/core/lib/slice/percent_encoding.h
index faae26a683..e6f85120c3 100644
--- a/src/core/lib/slice/percent_encoding.h
+++ b/src/core/lib/slice/percent_encoding.h
@@ -30,6 +30,10 @@
 
 #include <grpc/slice.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* URL percent encoding spec bitfield (usabel as 'unreserved_bytes' in
    grpc_percent_encode_slice, grpc_strict_percent_decode_slice).
    Flags [A-Za-z0-9-_.~] as unreserved bytes for the percent encoding routines
@@ -60,4 +64,8 @@ bool grpc_strict_percent_decode_slice(grpc_slice slice_in,
    This cannot fail. */
 grpc_slice grpc_permissive_percent_decode_slice(grpc_slice slice_in);
 
-#endif /* GRPC_CORE_LIB_SLICE_PERCENT_ENCODING_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SLICE_PERCENT_ENCODING_H */
\ No newline at end of file
diff --git a/src/core/lib/slice/slice.c b/src/core/lib/slice/slice.cc
index 0764eda052..0764eda052 100644
--- a/src/core/lib/slice/slice.c
+++ b/src/core/lib/slice/slice.cc
diff --git a/src/core/lib/slice/slice_buffer.c b/src/core/lib/slice/slice_buffer.cc
index 63ffc0b00d..63ffc0b00d 100644
--- a/src/core/lib/slice/slice_buffer.c
+++ b/src/core/lib/slice/slice_buffer.cc
diff --git a/src/core/lib/slice/slice_hash_table.c b/src/core/lib/slice/slice_hash_table.cc
index 6c2c9c201c..6c2c9c201c 100644
--- a/src/core/lib/slice/slice_hash_table.c
+++ b/src/core/lib/slice/slice_hash_table.cc
diff --git a/src/core/lib/slice/slice_hash_table.h b/src/core/lib/slice/slice_hash_table.h
index 339078fef5..3c3f0e61f3 100644
--- a/src/core/lib/slice/slice_hash_table.h
+++ b/src/core/lib/slice/slice_hash_table.h
@@ -19,6 +19,10 @@
 
 #include "src/core/lib/transport/metadata.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** Hash table implementation.
  *
  * This implementation uses open addressing
@@ -67,4 +71,8 @@ void *grpc_slice_hash_table_get(const grpc_slice_hash_table *table,
 int grpc_slice_hash_table_cmp(const grpc_slice_hash_table *a,
                               const grpc_slice_hash_table *b);
 
-#endif /* GRPC_CORE_LIB_SLICE_SLICE_HASH_TABLE_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SLICE_SLICE_HASH_TABLE_H */
\ No newline at end of file
diff --git a/src/core/lib/slice/slice_intern.c b/src/core/lib/slice/slice_intern.cc
index ec71b3ca1d..1ea9a2aa67 100644
--- a/src/core/lib/slice/slice_intern.c
+++ b/src/core/lib/slice/slice_intern.cc
@@ -18,6 +18,7 @@
 
 #include "src/core/lib/slice/slice_internal.h"
 
+#include <inttypes.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
diff --git a/src/core/lib/slice/slice_internal.h b/src/core/lib/slice/slice_internal.h
index 6df0b4b50b..8591185c53 100644
--- a/src/core/lib/slice/slice_internal.h
+++ b/src/core/lib/slice/slice_internal.h
@@ -24,6 +24,10 @@
 
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_slice grpc_slice_ref_internal(grpc_slice slice);
 void grpc_slice_unref_internal(grpc_exec_ctx *exec_ctx, grpc_slice slice);
 void grpc_slice_buffer_reset_and_unref_internal(grpc_exec_ctx *exec_ctx,
@@ -46,4 +50,8 @@ grpc_slice grpc_slice_maybe_static_intern(grpc_slice slice,
 uint32_t grpc_static_slice_hash(grpc_slice s);
 int grpc_static_slice_eq(grpc_slice a, grpc_slice b);
 
-#endif /* GRPC_CORE_LIB_SLICE_SLICE_INTERNAL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SLICE_SLICE_INTERNAL_H */
\ No newline at end of file
diff --git a/src/core/lib/slice/slice_string_helpers.c b/src/core/lib/slice/slice_string_helpers.cc
index 3f054daf32..3f054daf32 100644
--- a/src/core/lib/slice/slice_string_helpers.c
+++ b/src/core/lib/slice/slice_string_helpers.cc
diff --git a/src/core/lib/slice/slice_traits.h b/src/core/lib/slice/slice_traits.h
index 4b898bdcd4..1eda17cf00 100644
--- a/src/core/lib/slice/slice_traits.h
+++ b/src/core/lib/slice/slice_traits.h
@@ -22,8 +22,16 @@
 #include <grpc/slice.h>
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 bool grpc_slice_is_legal_header(grpc_slice s);
 bool grpc_slice_is_legal_nonbin_header(grpc_slice s);
 bool grpc_slice_is_bin_suffixed(grpc_slice s);
 
-#endif /* GRPC_CORE_LIB_SLICE_SLICE_TRAITS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SLICE_SLICE_TRAITS_H */
\ No newline at end of file
diff --git a/src/core/lib/support/alloc.c b/src/core/lib/support/alloc.cc
index 886d69d64c..886d69d64c 100644
--- a/src/core/lib/support/alloc.c
+++ b/src/core/lib/support/alloc.cc
diff --git a/src/core/lib/support/arena.c b/src/core/lib/support/arena.cc
index 9e0f73ae3d..9e0f73ae3d 100644
--- a/src/core/lib/support/arena.c
+++ b/src/core/lib/support/arena.cc
diff --git a/src/core/lib/support/arena.h b/src/core/lib/support/arena.h
index 47f0e4d16b..8a50786348 100644
--- a/src/core/lib/support/arena.h
+++ b/src/core/lib/support/arena.h
@@ -27,6 +27,10 @@
 
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct gpr_arena gpr_arena;
 
 // Create an arena, with \a initial_size bytes in the first allocated buffer
@@ -36,4 +40,8 @@ void *gpr_arena_alloc(gpr_arena *arena, size_t size);
 // Destroy an arena, returning the total number of bytes allocated
 size_t gpr_arena_destroy(gpr_arena *arena);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_ARENA_H */
diff --git a/src/core/lib/support/atm.c b/src/core/lib/support/atm.cc
index 2f37d62f76..2f37d62f76 100644
--- a/src/core/lib/support/atm.c
+++ b/src/core/lib/support/atm.cc
diff --git a/src/core/lib/support/avl.c b/src/core/lib/support/avl.cc
index 0e28b24c98..0e28b24c98 100644
--- a/src/core/lib/support/avl.c
+++ b/src/core/lib/support/avl.cc
diff --git a/src/core/lib/support/cmdline.c b/src/core/lib/support/cmdline.cc
index 9fb80d4460..9fb80d4460 100644
--- a/src/core/lib/support/cmdline.c
+++ b/src/core/lib/support/cmdline.cc
diff --git a/src/core/lib/support/cpu_iphone.c b/src/core/lib/support/cpu_iphone.cc
index dfd69b9fd8..2847e03ba5 100644
--- a/src/core/lib/support/cpu_iphone.c
+++ b/src/core/lib/support/cpu_iphone.cc
@@ -18,6 +18,8 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <grpc/support/cpu.h>
+
 #ifdef GPR_CPU_IPHONE
 
 /* Probably 2 instead of 1, but see comment on gpr_cpu_current_cpu. */
diff --git a/src/core/lib/support/cpu_linux.c b/src/core/lib/support/cpu_linux.cc
index 2280668442..2280668442 100644
--- a/src/core/lib/support/cpu_linux.c
+++ b/src/core/lib/support/cpu_linux.cc
diff --git a/src/core/lib/support/cpu_posix.c b/src/core/lib/support/cpu_posix.cc
index a1ba8202a8..503a96b4c8 100644
--- a/src/core/lib/support/cpu_posix.c
+++ b/src/core/lib/support/cpu_posix.cc
@@ -24,6 +24,7 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <grpc/support/cpu.h>
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/useful.h>
diff --git a/src/core/lib/support/cpu_windows.c b/src/core/lib/support/cpu_windows.cc
index af26ff3679..8d89453403 100644
--- a/src/core/lib/support/cpu_windows.c
+++ b/src/core/lib/support/cpu_windows.cc
@@ -19,6 +19,7 @@
 #include <grpc/support/port_platform.h>
 
 #ifdef GPR_WINDOWS
+#include <grpc/support/cpu.h>
 #include <grpc/support/log.h>
 
 unsigned gpr_cpu_num_cores(void) {
diff --git a/src/core/lib/support/env_linux.c b/src/core/lib/support/env_linux.cc
index 4c45a977ca..4c45a977ca 100644
--- a/src/core/lib/support/env_linux.c
+++ b/src/core/lib/support/env_linux.cc
diff --git a/src/core/lib/support/env_posix.c b/src/core/lib/support/env_posix.cc
index b88822ca02..b88822ca02 100644
--- a/src/core/lib/support/env_posix.c
+++ b/src/core/lib/support/env_posix.cc
diff --git a/src/core/lib/support/env_windows.c b/src/core/lib/support/env_windows.cc
index 652eeb61c6..73c643c560 100644
--- a/src/core/lib/support/env_windows.c
+++ b/src/core/lib/support/env_windows.cc
@@ -45,7 +45,7 @@ char *gpr_getenv(const char *name) {
   ret = GetEnvironmentVariable(tname, NULL, 0);
   if (ret == 0) return NULL;
   size = ret * (DWORD)sizeof(TCHAR);
-  tresult = gpr_malloc(size);
+  tresult = (LPTSTR)gpr_malloc(size);
   ret = GetEnvironmentVariable(tname, tresult, size);
   gpr_free(tname);
   if (ret == 0) {
diff --git a/src/core/lib/support/histogram.c b/src/core/lib/support/histogram.cc
index 6d5ead9aa6..6d5ead9aa6 100644
--- a/src/core/lib/support/histogram.c
+++ b/src/core/lib/support/histogram.cc
diff --git a/src/core/lib/support/host_port.c b/src/core/lib/support/host_port.cc
index 3302e574ab..3302e574ab 100644
--- a/src/core/lib/support/host_port.c
+++ b/src/core/lib/support/host_port.cc
diff --git a/src/core/lib/support/log.c b/src/core/lib/support/log.cc
index fadb4d9a2c..69f92e001c 100644
--- a/src/core/lib/support/log.c
+++ b/src/core/lib/support/log.cc
@@ -27,7 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
-extern void gpr_default_log(gpr_log_func_args *args);
+extern "C" void gpr_default_log(gpr_log_func_args *args);
 static gpr_atm g_log_func = (gpr_atm)gpr_default_log;
 static gpr_atm g_min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
 
diff --git a/src/core/lib/support/log_android.c b/src/core/lib/support/log_android.cc
index 6f1cec51f1..9e8529cbac 100644
--- a/src/core/lib/support/log_android.c
+++ b/src/core/lib/support/log_android.cc
@@ -39,8 +39,8 @@ static android_LogPriority severity_to_log_priority(gpr_log_severity severity) {
   return ANDROID_LOG_DEFAULT;
 }
 
-void gpr_log(const char *file, int line, gpr_log_severity severity,
-             const char *format, ...) {
+extern "C" void gpr_log(const char *file, int line, gpr_log_severity severity,
+                        const char *format, ...) {
   char *message = NULL;
   va_list args;
   va_start(args, format);
@@ -50,8 +50,8 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   free(message);
 }
 
-void gpr_default_log(gpr_log_func_args *args) {
-  char *final_slash;
+extern "C" void gpr_default_log(gpr_log_func_args *args) {
+  const char *final_slash;
   const char *display_file;
   char *output = NULL;
 
diff --git a/src/core/lib/support/log_linux.c b/src/core/lib/support/log_linux.cc
index 7755018693..0914acedf4 100644
--- a/src/core/lib/support/log_linux.c
+++ b/src/core/lib/support/log_linux.cc
@@ -56,7 +56,7 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   free(message);
 }
 
-void gpr_default_log(gpr_log_func_args *args) {
+extern "C" void gpr_default_log(gpr_log_func_args *args) {
   const char *final_slash;
   char *prefix;
   const char *display_file;
diff --git a/src/core/lib/support/log_posix.c b/src/core/lib/support/log_posix.cc
index 8b376fce41..29530c858f 100644
--- a/src/core/lib/support/log_posix.c
+++ b/src/core/lib/support/log_posix.cc
@@ -48,7 +48,7 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   } else if ((size_t)ret <= sizeof(buf) - 1) {
     message = buf;
   } else {
-    message = allocated = gpr_malloc((size_t)ret + 1);
+    message = allocated = (char *)gpr_malloc((size_t)ret + 1);
     va_start(args, format);
     vsnprintf(message, (size_t)(ret + 1), format, args);
     va_end(args);
@@ -57,8 +57,8 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   gpr_free(allocated);
 }
 
-void gpr_default_log(gpr_log_func_args *args) {
-  char *final_slash;
+extern "C" void gpr_default_log(gpr_log_func_args *args) {
+  const char *final_slash;
   const char *display_file;
   char time_buffer[64];
   time_t timer;
diff --git a/src/core/lib/support/log_windows.c b/src/core/lib/support/log_windows.cc
index 0fdab79ae6..ee52abea73 100644
--- a/src/core/lib/support/log_windows.c
+++ b/src/core/lib/support/log_windows.cc
@@ -47,7 +47,7 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
   } else {
     /* Allocate a new buffer, with space for the NUL terminator. */
     size_t strp_buflen = (size_t)ret + 1;
-    message = gpr_malloc(strp_buflen);
+    message = (char *)gpr_malloc(strp_buflen);
 
     /* Print to the buffer. */
     va_start(args, format);
@@ -65,8 +65,8 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
 }
 
 /* Simple starter implementation */
-void gpr_default_log(gpr_log_func_args *args) {
-  char *final_slash;
+extern "C" void gpr_default_log(gpr_log_func_args *args) {
+  const char *final_slash;
   const char *display_file;
   char time_buffer[64];
   time_t timer;
diff --git a/src/core/lib/support/mpscq.c b/src/core/lib/support/mpscq.cc
index e9f893988d..e9f893988d 100644
--- a/src/core/lib/support/mpscq.c
+++ b/src/core/lib/support/mpscq.cc
diff --git a/src/core/lib/support/mpscq.h b/src/core/lib/support/mpscq.h
index daa51768f7..ca63a044bb 100644
--- a/src/core/lib/support/mpscq.h
+++ b/src/core/lib/support/mpscq.h
@@ -23,6 +23,10 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Multiple-producer single-consumer lock free queue, based upon the
 // implementation from Dmitry Vyukov here:
 // http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue
@@ -50,4 +54,8 @@ gpr_mpscq_node *gpr_mpscq_pop(gpr_mpscq *q);
 // Pop a node; sets *empty to true if the queue is empty, or false if it is not
 gpr_mpscq_node *gpr_mpscq_pop_and_check_end(gpr_mpscq *q, bool *empty);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_MPSCQ_H */
diff --git a/src/core/lib/support/murmur_hash.c b/src/core/lib/support/murmur_hash.cc
index f06b970de7..f06b970de7 100644
--- a/src/core/lib/support/murmur_hash.c
+++ b/src/core/lib/support/murmur_hash.cc
diff --git a/src/core/lib/support/murmur_hash.h b/src/core/lib/support/murmur_hash.h
index 7510b4d09c..a4c642e49f 100644
--- a/src/core/lib/support/murmur_hash.h
+++ b/src/core/lib/support/murmur_hash.h
@@ -23,7 +23,15 @@
 
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* compute the hash of key (length len) */
 uint32_t gpr_murmur_hash3(const void *key, size_t len, uint32_t seed);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_MURMUR_HASH_H */
diff --git a/src/core/lib/support/spinlock.h b/src/core/lib/support/spinlock.h
index 37adda11b0..47584f6279 100644
--- a/src/core/lib/support/spinlock.h
+++ b/src/core/lib/support/spinlock.h
@@ -25,9 +25,14 @@
    a concurrency code smell. */
 typedef struct { gpr_atm atm; } gpr_spinlock;
 
+#ifdef __cplusplus
+#define GPR_SPINLOCK_INITIALIZER (gpr_spinlock{0})
+#else
 #define GPR_SPINLOCK_INITIALIZER ((gpr_spinlock){0})
+#endif
 #define GPR_SPINLOCK_STATIC_INITIALIZER \
   { 0 }
+
 #define gpr_spinlock_trylock(lock) (gpr_atm_acq_cas(&(lock)->atm, 0, 1))
 #define gpr_spinlock_unlock(lock) (gpr_atm_rel_store(&(lock)->atm, 0))
 #define gpr_spinlock_lock(lock) \
diff --git a/src/core/lib/support/stack_lockfree.c b/src/core/lib/support/stack_lockfree.cc
index 0fb64ed001..0fb64ed001 100644
--- a/src/core/lib/support/stack_lockfree.c
+++ b/src/core/lib/support/stack_lockfree.cc
diff --git a/src/core/lib/support/stack_lockfree.h b/src/core/lib/support/stack_lockfree.h
index 6324211b72..706f63fbf6 100644
--- a/src/core/lib/support/stack_lockfree.h
+++ b/src/core/lib/support/stack_lockfree.h
@@ -21,6 +21,10 @@
 
 #include <stddef.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct gpr_stack_lockfree gpr_stack_lockfree;
 
 /* This stack must specify the maximum number of entries to track.
@@ -35,4 +39,8 @@ int gpr_stack_lockfree_push(gpr_stack_lockfree *, int entry);
 /* Returns -1 on empty or the actual entry number */
 int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_STACK_LOCKFREE_H */
diff --git a/src/core/lib/support/string.c b/src/core/lib/support/string.cc
index 6b172df82f..d55863892f 100644
--- a/src/core/lib/support/string.c
+++ b/src/core/lib/support/string.cc
@@ -27,6 +27,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/port_platform.h>
+#include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
 char *gpr_strdup(const char *src) {
diff --git a/src/core/lib/support/string_posix.c b/src/core/lib/support/string_posix.cc
index e768faf739..92de21a6e1 100644
--- a/src/core/lib/support/string_posix.c
+++ b/src/core/lib/support/string_posix.cc
@@ -25,6 +25,7 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
 
 int gpr_asprintf(char **strp, const char *format, ...) {
   va_list args;
diff --git a/src/core/lib/support/string_util_windows.c b/src/core/lib/support/string_util_windows.cc
index 2a03404448..b365512ee3 100644
--- a/src/core/lib/support/string_util_windows.c
+++ b/src/core/lib/support/string_util_windows.cc
@@ -26,15 +26,18 @@
    anything else, especially strsafe.h. */
 #include <wchar.h>
 
+#include <inttypes.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 #include <strsafe.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/log_windows.h>
 #include <grpc/support/string_util.h>
 
 #include "src/core/lib/support/string.h"
+#include "src/core/lib/support/string_windows.h"
 
 #if defined UNICODE || defined _UNICODE
 LPTSTR
@@ -42,7 +45,7 @@ gpr_char_to_tchar(LPCSTR input) {
   LPTSTR ret;
   int needed = MultiByteToWideChar(CP_UTF8, 0, input, -1, NULL, 0);
   if (needed <= 0) return NULL;
-  ret = gpr_malloc((unsigned)needed * sizeof(TCHAR));
+  ret = (LPTSTR)gpr_malloc((unsigned)needed * sizeof(TCHAR));
   MultiByteToWideChar(CP_UTF8, 0, input, -1, ret, needed);
   return ret;
 }
@@ -52,14 +55,14 @@ gpr_tchar_to_char(LPCTSTR input) {
   LPSTR ret;
   int needed = WideCharToMultiByte(CP_UTF8, 0, input, -1, NULL, 0, NULL, NULL);
   if (needed <= 0) return NULL;
-  ret = gpr_malloc((unsigned)needed);
+  ret = (LPSTR)gpr_malloc((unsigned)needed);
   WideCharToMultiByte(CP_UTF8, 0, input, -1, ret, needed, NULL, NULL);
   return ret;
 }
 #else
-char *gpr_tchar_to_char(LPTSTR input) { return gpr_strdup(input); }
+LPSTR gpr_tchar_to_char(LPCTSTR input) { return (LPSTR)gpr_strdup(input); }
 
-char *gpr_char_to_tchar(LPTSTR input) { return gpr_strdup(input); }
+LPTSTR gpr_char_to_tchar(LPCTSTR input) { return (LPTSTR)gpr_strdup(input); }
 #endif
 
 char *gpr_format_message(int messageid) {
diff --git a/src/core/lib/support/string_windows.c b/src/core/lib/support/string_windows.cc
index 50278d9559..d37863c066 100644
--- a/src/core/lib/support/string_windows.c
+++ b/src/core/lib/support/string_windows.cc
@@ -27,6 +27,7 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
 
 #include "src/core/lib/support/string.h"
 
@@ -46,7 +47,7 @@ int gpr_asprintf(char **strp, const char *format, ...) {
 
   /* Allocate a new buffer, with space for the NUL terminator. */
   strp_buflen = (size_t)ret + 1;
-  if ((*strp = gpr_malloc(strp_buflen)) == NULL) {
+  if ((*strp = (char *)gpr_malloc(strp_buflen)) == NULL) {
     /* This shouldn't happen, because gpr_malloc() calls abort(). */
     return -1;
   }
diff --git a/src/core/lib/support/string_windows.h b/src/core/lib/support/string_windows.h
index 7c7f31e7aa..6771647581 100644
--- a/src/core/lib/support/string_windows.h
+++ b/src/core/lib/support/string_windows.h
@@ -21,6 +21,10 @@
 
 #include <grpc/support/port_platform.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifdef GPR_WINDOWS
 
 /* These allocate new strings using gpr_malloc to convert from and to utf-8. */
@@ -29,4 +33,8 @@ LPSTR gpr_tchar_to_char(LPCTSTR input);
 
 #endif /* GPR_WINDOWS */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_STRING_WINDOWS_H */
diff --git a/src/core/lib/support/subprocess_posix.c b/src/core/lib/support/subprocess_posix.cc
index af75162ee9..af75162ee9 100644
--- a/src/core/lib/support/subprocess_posix.c
+++ b/src/core/lib/support/subprocess_posix.cc
diff --git a/src/core/lib/support/subprocess_windows.c b/src/core/lib/support/subprocess_windows.cc
index 7412f8d344..6769f1d3a4 100644
--- a/src/core/lib/support/subprocess_windows.c
+++ b/src/core/lib/support/subprocess_windows.cc
@@ -61,7 +61,7 @@ gpr_subprocess *gpr_subprocess_create(int argc, const char **argv) {
   }
   gpr_free(args_tchar);
 
-  r = gpr_malloc(sizeof(gpr_subprocess));
+  r = (gpr_subprocess *)gpr_malloc(sizeof(gpr_subprocess));
   memset(r, 0, sizeof(*r));
   r->pi = pi;
   return r;
diff --git a/src/core/lib/support/sync.c b/src/core/lib/support/sync.cc
index 994dcb0e14..994dcb0e14 100644
--- a/src/core/lib/support/sync.c
+++ b/src/core/lib/support/sync.cc
diff --git a/src/core/lib/support/sync_posix.c b/src/core/lib/support/sync_posix.cc
index 62d800b18c..62d800b18c 100644
--- a/src/core/lib/support/sync_posix.c
+++ b/src/core/lib/support/sync_posix.cc
diff --git a/src/core/lib/support/sync_windows.c b/src/core/lib/support/sync_windows.cc
index 008c5aecba..62fdd40af7 100644
--- a/src/core/lib/support/sync_windows.c
+++ b/src/core/lib/support/sync_windows.cc
@@ -104,7 +104,7 @@ struct run_once_func_arg {
   void (*init_function)(void);
 };
 static BOOL CALLBACK run_once_func(gpr_once *once, void *v, void **pv) {
-  struct run_once_func_arg *arg = v;
+  struct run_once_func_arg *arg = (struct run_once_func_arg *)v;
   (*arg->init_function)();
   return 1;
 }
diff --git a/src/core/lib/support/thd.c b/src/core/lib/support/thd.cc
index ca62615d65..ca62615d65 100644
--- a/src/core/lib/support/thd.c
+++ b/src/core/lib/support/thd.cc
diff --git a/src/core/lib/support/thd_posix.c b/src/core/lib/support/thd_posix.cc
index 98afd10df7..98afd10df7 100644
--- a/src/core/lib/support/thd_posix.c
+++ b/src/core/lib/support/thd_posix.cc
diff --git a/src/core/lib/support/thd_windows.c b/src/core/lib/support/thd_windows.cc
index 54533e9412..1a82805dd9 100644
--- a/src/core/lib/support/thd_windows.c
+++ b/src/core/lib/support/thd_windows.cc
@@ -66,7 +66,7 @@ static DWORD WINAPI thread_body(void *v) {
 int gpr_thd_new(gpr_thd_id *t, void (*thd_body)(void *arg), void *arg,
                 const gpr_thd_options *options) {
   HANDLE handle;
-  struct thd_info *info = gpr_malloc(sizeof(*info));
+  struct thd_info *info = (struct thd_info *)gpr_malloc(sizeof(*info));
   info->body = thd_body;
   info->arg = arg;
   *t = 0;
diff --git a/src/core/lib/support/time.c b/src/core/lib/support/time.cc
index 6903674d75..6903674d75 100644
--- a/src/core/lib/support/time.c
+++ b/src/core/lib/support/time.cc
diff --git a/src/core/lib/support/time_posix.c b/src/core/lib/support/time_posix.cc
index 3ead40d807..3267ea6b54 100644
--- a/src/core/lib/support/time_posix.c
+++ b/src/core/lib/support/time_posix.cc
@@ -30,7 +30,6 @@
 #include <grpc/support/atm.h>
 #include <grpc/support/log.h>
 #include <grpc/support/time.h>
-#include "src/core/lib/support/block_annotate.h"
 
 static struct timespec timespec_from_gpr(gpr_timespec gts) {
   struct timespec rv;
@@ -128,7 +127,9 @@ static gpr_timespec now_impl(gpr_clock_type clock) {
 }
 #endif
 
+extern "C" {
 gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
+}
 
 #ifdef GPR_LOW_LEVEL_COUNTERS
 gpr_atm gpr_now_call_count;
@@ -157,9 +158,7 @@ void gpr_sleep_until(gpr_timespec until) {
 
     delta = gpr_time_sub(until, now);
     delta_ts = timespec_from_gpr(delta);
-    GRPC_SCHEDULING_START_BLOCKING_REGION;
     ns_result = nanosleep(&delta_ts, NULL);
-    GRPC_SCHEDULING_END_BLOCKING_REGION;
     if (ns_result == 0) {
       break;
     }
diff --git a/src/core/lib/support/time_precise.c b/src/core/lib/support/time_precise.cc
index 6ce19e53cc..05ef7c59bc 100644
--- a/src/core/lib/support/time_precise.c
+++ b/src/core/lib/support/time_precise.cc
@@ -20,6 +20,8 @@
 #include <grpc/support/time.h>
 #include <stdio.h>
 
+#include "src/core/lib/support/time_precise.h"
+
 #ifdef GRPC_TIMERS_RDTSC
 #if defined(__i386__)
 static void gpr_get_cycle_counter(int64_t int *clk) {
diff --git a/src/core/lib/support/time_precise.h b/src/core/lib/support/time_precise.h
index aa28d6d7c4..cb15cdf919 100644
--- a/src/core/lib/support/time_precise.h
+++ b/src/core/lib/support/time_precise.h
@@ -21,7 +21,15 @@
 
 #include <grpc/support/time.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void gpr_precise_clock_init(void);
 void gpr_precise_clock_now(gpr_timespec *clk);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SUPPORT_TIME_PRECISE_H */
diff --git a/src/core/lib/support/time_windows.c b/src/core/lib/support/time_windows.cc
index 40df3761c0..08c1b22964 100644
--- a/src/core/lib/support/time_windows.c
+++ b/src/core/lib/support/time_windows.cc
@@ -28,7 +28,6 @@
 #include <process.h>
 #include <sys/timeb.h>
 
-#include "src/core/lib/support/block_annotate.h"
 #include "src/core/lib/support/time_precise.h"
 
 static LARGE_INTEGER g_start_time;
@@ -69,7 +68,9 @@ static gpr_timespec now_impl(gpr_clock_type clock) {
   return now_tv;
 }
 
+extern "C" {
 gpr_timespec (*gpr_now_impl)(gpr_clock_type clock_type) = now_impl;
+}
 
 gpr_timespec gpr_now(gpr_clock_type clock_type) {
   return gpr_now_impl(clock_type);
@@ -92,9 +93,7 @@ void gpr_sleep_until(gpr_timespec until) {
     sleep_millis =
         delta.tv_sec * GPR_MS_PER_SEC + delta.tv_nsec / GPR_NS_PER_MS;
     GPR_ASSERT((sleep_millis >= 0) && (sleep_millis <= INT_MAX));
-    GRPC_SCHEDULING_START_BLOCKING_REGION;
     Sleep((DWORD)sleep_millis);
-    GRPC_SCHEDULING_END_BLOCKING_REGION;
   }
 }
 
diff --git a/src/core/lib/support/tls_pthread.c b/src/core/lib/support/tls_pthread.cc
index 9ebee577fe..9ebee577fe 100644
--- a/src/core/lib/support/tls_pthread.c
+++ b/src/core/lib/support/tls_pthread.cc
diff --git a/src/core/lib/support/tmpfile_msys.c b/src/core/lib/support/tmpfile_msys.cc
index 614c0a4a18..614c0a4a18 100644
--- a/src/core/lib/support/tmpfile_msys.c
+++ b/src/core/lib/support/tmpfile_msys.cc
diff --git a/src/core/lib/support/tmpfile_posix.c b/src/core/lib/support/tmpfile_posix.cc
index 7ad3af0a57..7ad3af0a57 100644
--- a/src/core/lib/support/tmpfile_posix.c
+++ b/src/core/lib/support/tmpfile_posix.cc
diff --git a/src/core/lib/support/tmpfile_windows.c b/src/core/lib/support/tmpfile_windows.cc
index 47b4510a72..47b4510a72 100644
--- a/src/core/lib/support/tmpfile_windows.c
+++ b/src/core/lib/support/tmpfile_windows.cc
diff --git a/src/core/lib/support/wrap_memcpy.c b/src/core/lib/support/wrap_memcpy.cc
index cff056dc3b..c2362bf5b8 100644
--- a/src/core/lib/support/wrap_memcpy.c
+++ b/src/core/lib/support/wrap_memcpy.cc
@@ -26,6 +26,7 @@
  * Enable by setting LDFLAGS=-Wl,-wrap,memcpy when linking.
  */
 
+extern "C" {
 #ifdef __linux__
 #if defined(__x86_64__) && !defined(GPR_MUSL_LIBC_COMPAT)
 __asm__(".symver memcpy,memcpy@GLIBC_2.2.5");
@@ -38,3 +39,4 @@ void *__wrap_memcpy(void *destination, const void *source, size_t num) {
 }
 #endif
 #endif
+}
diff --git a/src/core/lib/surface/alarm.c b/src/core/lib/surface/alarm.cc
index 7712f560b9..16a16bfd93 100644
--- a/src/core/lib/surface/alarm.c
+++ b/src/core/lib/surface/alarm.cc
@@ -15,6 +15,10 @@
  * limitations under the License.
  *
  */
+#include <grpc/support/port_platform.h>
+
+#include <inttypes.h>
+
 #include "src/core/lib/surface/alarm_internal.h"
 
 #include <grpc/grpc.h>
@@ -122,8 +126,7 @@ void grpc_alarm_set(grpc_alarm *alarm, grpc_completion_queue *cq,
 
   GPR_ASSERT(grpc_cq_begin_op(cq, tag));
   grpc_timer_init(&exec_ctx, &alarm->alarm,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  &alarm->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
+                  grpc_timespec_to_millis_round_up(deadline), &alarm->on_alarm);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
diff --git a/src/core/lib/surface/alarm_internal.h b/src/core/lib/surface/alarm_internal.h
index 7f2126c5c9..136b60547f 100644
--- a/src/core/lib/surface/alarm_internal.h
+++ b/src/core/lib/surface/alarm_internal.h
@@ -22,6 +22,10 @@
 #include <grpc/support/log.h>
 #include "src/core/lib/debug/trace.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef NDEBUG
 
 extern grpc_tracer_flag grpc_trace_alarm_refcount;
@@ -37,4 +41,8 @@ extern grpc_tracer_flag grpc_trace_alarm_refcount;
 
 #endif /* defined(NDEBUG) */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_ALARM_INTERNAL_H */
diff --git a/src/core/lib/surface/api_trace.c b/src/core/lib/surface/api_trace.cc
index 56973303da..56973303da 100644
--- a/src/core/lib/surface/api_trace.c
+++ b/src/core/lib/surface/api_trace.cc
diff --git a/src/core/lib/surface/api_trace.h b/src/core/lib/surface/api_trace.h
index 849cbaaef6..105abdf629 100644
--- a/src/core/lib/surface/api_trace.h
+++ b/src/core/lib/surface/api_trace.h
@@ -22,6 +22,10 @@
 #include <grpc/support/log.h>
 #include "src/core/lib/debug/trace.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_tracer_flag grpc_api_trace;
 
 /* Provide unwrapping macros because we're in C89 and variadic macros weren't
@@ -47,4 +51,8 @@ extern grpc_tracer_flag grpc_api_trace;
     gpr_log(GPR_INFO, fmt GRPC_API_TRACE_UNWRAP##nargs args); \
   }
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_API_TRACE_H */
diff --git a/src/core/lib/surface/byte_buffer.c b/src/core/lib/surface/byte_buffer.cc
index 7ed550ef87..7ed550ef87 100644
--- a/src/core/lib/surface/byte_buffer.c
+++ b/src/core/lib/surface/byte_buffer.cc
diff --git a/src/core/lib/surface/byte_buffer_reader.c b/src/core/lib/surface/byte_buffer_reader.cc
index 373ee1fe8b..373ee1fe8b 100644
--- a/src/core/lib/surface/byte_buffer_reader.c
+++ b/src/core/lib/surface/byte_buffer_reader.cc
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.cc
index 4f8cf08c52..781100d98a 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.cc
@@ -41,6 +41,7 @@
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/call.h"
+#include "src/core/lib/surface/call_test_only.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/completion_queue.h"
 #include "src/core/lib/surface/validate_metadata.h"
@@ -93,10 +94,11 @@ static gpr_atm pack_received_status(received_status r) {
 }
 
 static received_status unpack_received_status(gpr_atm atm) {
-  return (atm & 1) == 0
-             ? (received_status){.is_set = false, .error = GRPC_ERROR_NONE}
-             : (received_status){.is_set = true,
-                                 .error = (grpc_error *)(atm & ~(gpr_atm)1)};
+  if ((atm & 1) == 0) {
+    return {false, GRPC_ERROR_NONE};
+  } else {
+    return {true, (grpc_error *)(atm & ~(gpr_atm)1)};
+  }
 }
 
 #define MAX_ERRORS_PER_BATCH 4
@@ -214,7 +216,7 @@ struct grpc_call {
      server, it's trailing metadata */
   grpc_linked_mdelem send_extra_metadata[MAX_SEND_EXTRA_METADATA_COUNT];
   int send_extra_metadata_count;
-  gpr_timespec send_deadline;
+  grpc_millis send_deadline;
 
   grpc_slice_buffer_stream sending_stream;
 
@@ -281,7 +283,7 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call_stack,
                          grpc_error *error);
 static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
                                   grpc_error *error);
-static void get_final_status(grpc_call *call,
+static void get_final_status(grpc_exec_ctx *exec_ctx, grpc_call *call,
                              void (*set_value)(grpc_status_code code,
                                                void *user_data),
                              void *set_value_user_data, grpc_slice *details);
@@ -370,11 +372,10 @@ grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
   }
   for (i = 0; i < 2; i++) {
     for (j = 0; j < 2; j++) {
-      call->metadata_batch[i][j].deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+      call->metadata_batch[i][j].deadline = GRPC_MILLIS_INF_FUTURE;
     }
   }
-  gpr_timespec send_deadline =
-      gpr_convert_clock_type(args->send_deadline, GPR_CLOCK_MONOTONIC);
+  grpc_millis send_deadline = args->send_deadline;
 
   bool immediately_cancel = false;
 
@@ -392,10 +393,7 @@ grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
     gpr_mu_lock(&pc->child_list_mu);
 
     if (args->propagation_mask & GRPC_PROPAGATE_DEADLINE) {
-      send_deadline = gpr_time_min(
-          gpr_convert_clock_type(send_deadline,
-                                 args->parent->send_deadline.clock_type),
-          args->parent->send_deadline);
+      send_deadline = GPR_MIN(send_deadline, args->parent->send_deadline);
     }
     /* for now GRPC_PROPAGATE_TRACING_CONTEXT *MUST* be passed with
      * GRPC_PROPAGATE_STATS_CONTEXT */
@@ -439,15 +437,14 @@ grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
 
   GRPC_CHANNEL_INTERNAL_REF(args->channel, "call");
   /* initial refcount dropped by grpc_call_unref */
-  grpc_call_element_args call_args = {
-      .call_stack = CALL_STACK_FROM_CALL(call),
-      .server_transport_data = args->server_transport_data,
-      .context = call->context,
-      .path = path,
-      .start_time = call->start_time,
-      .deadline = send_deadline,
-      .arena = call->arena,
-      .call_combiner = &call->call_combiner};
+  grpc_call_element_args call_args = {CALL_STACK_FROM_CALL(call),
+                                      args->server_transport_data,
+                                      call->context,
+                                      path,
+                                      call->start_time,
+                                      send_deadline,
+                                      call->arena,
+                                      &call->call_combiner};
   add_init_error(&error, grpc_call_stack_init(exec_ctx, channel_stack, 1,
                                               destroy_call, call, &call_args));
   if (error != GRPC_ERROR_NONE) {
@@ -550,8 +547,8 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call,
     GRPC_CQ_INTERNAL_UNREF(exec_ctx, c->cq, "bind");
   }
 
-  get_final_status(c, set_status_value_directly, &c->final_info.final_status,
-                   NULL);
+  get_final_status(exec_ctx, c, set_status_value_directly,
+                   &c->final_info.final_status, NULL);
   c->final_info.stats.latency =
       gpr_time_sub(gpr_now(GPR_CLOCK_MONOTONIC), c->start_time);
 
@@ -737,13 +734,16 @@ static void cancel_with_status(grpc_exec_ctx *exec_ctx, grpc_call *c,
  * FINAL STATUS CODE MANIPULATION
  */
 
-static bool get_final_status_from(
-    grpc_call *call, grpc_error *error, bool allow_ok_status,
-    void (*set_value)(grpc_status_code code, void *user_data),
-    void *set_value_user_data, grpc_slice *details) {
+static bool get_final_status_from(grpc_exec_ctx *exec_ctx, grpc_call *call,
+                                  grpc_error *error, bool allow_ok_status,
+                                  void (*set_value)(grpc_status_code code,
+                                                    void *user_data),
+                                  void *set_value_user_data,
+                                  grpc_slice *details) {
   grpc_status_code code;
   grpc_slice slice = grpc_empty_slice();
-  grpc_error_get_status(error, call->send_deadline, &code, &slice, NULL);
+  grpc_error_get_status(exec_ctx, error, call->send_deadline, &code, &slice,
+                        NULL);
   if (code == GRPC_STATUS_OK && !allow_ok_status) {
     return false;
   }
@@ -755,7 +755,7 @@ static bool get_final_status_from(
   return true;
 }
 
-static void get_final_status(grpc_call *call,
+static void get_final_status(grpc_exec_ctx *exec_ctx, grpc_call *call,
                              void (*set_value)(grpc_status_code code,
                                                void *user_data),
                              void *set_value_user_data, grpc_slice *details) {
@@ -780,8 +780,9 @@ static void get_final_status(grpc_call *call,
     for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
       if (status[i].is_set &&
           grpc_error_has_clear_grpc_status(status[i].error)) {
-        if (get_final_status_from(call, status[i].error, allow_ok_status != 0,
-                                  set_value, set_value_user_data, details)) {
+        if (get_final_status_from(exec_ctx, call, status[i].error,
+                                  allow_ok_status != 0, set_value,
+                                  set_value_user_data, details)) {
           return;
         }
       }
@@ -789,8 +790,9 @@ static void get_final_status(grpc_call *call,
     /* If no clearly defined status exists, search for 'anything' */
     for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
       if (status[i].is_set) {
-        if (get_final_status_from(call, status[i].error, allow_ok_status != 0,
-                                  set_value, set_value_user_data, details)) {
+        if (get_final_status_from(exec_ctx, call, status[i].error,
+                                  allow_ok_status != 0, set_value,
+                                  set_value_user_data, details)) {
           return;
         }
       }
@@ -807,10 +809,8 @@ static void get_final_status(grpc_call *call,
 static void set_status_from_error(grpc_exec_ctx *exec_ctx, grpc_call *call,
                                   status_source source, grpc_error *error) {
   if (!gpr_atm_rel_cas(&call->status[source],
-                       pack_received_status((received_status){
-                           .is_set = false, .error = GRPC_ERROR_NONE}),
-                       pack_received_status((received_status){
-                           .is_set = true, .error = error}))) {
+                       pack_received_status({false, GRPC_ERROR_NONE}),
+                       pack_received_status({true, error}))) {
     GRPC_ERROR_UNREF(error);
   }
 }
@@ -1288,17 +1288,22 @@ static void post_batch_completion(grpc_exec_ctx *exec_ctx,
     }
 
     if (call->is_client) {
-      get_final_status(call, set_status_value_directly,
+      get_final_status(exec_ctx, call, set_status_value_directly,
                        call->final_op.client.status,
                        call->final_op.client.status_details);
     } else {
-      get_final_status(call, set_cancelled_value,
+      get_final_status(exec_ctx, call, set_cancelled_value,
                        call->final_op.server.cancelled, NULL);
     }
 
     GRPC_ERROR_UNREF(error);
     error = GRPC_ERROR_NONE;
   }
+  if (error != GRPC_ERROR_NONE && bctl->op.recv_message &&
+      *call->receiving_buffer != NULL) {
+    grpc_byte_buffer_destroy(*call->receiving_buffer);
+    *call->receiving_buffer = NULL;
+  }
 
   if (bctl->completion_data.notify_tag.is_closure) {
     /* unrefs bctl->error */
@@ -1408,7 +1413,8 @@ static void process_data_after_md(grpc_exec_ctx *exec_ctx,
       grpc_compression_algorithm algo;
       GPR_ASSERT(
           grpc_compression_algorithm_from_message_stream_compression_algorithm(
-              &algo, call->incoming_message_compression_algorithm, 0));
+              &algo, call->incoming_message_compression_algorithm,
+              (grpc_stream_compression_algorithm)0));
       *call->receiving_buffer =
           grpc_raw_compressed_byte_buffer_create(NULL, 0, algo);
     } else {
@@ -1552,11 +1558,8 @@ static void receiving_initial_metadata_ready(grpc_exec_ctx *exec_ctx,
     validate_filtered_metadata(exec_ctx, bctl);
     GPR_TIMER_END("validate_filtered_metadata", 0);
 
-    if (gpr_time_cmp(md->deadline, gpr_inf_future(md->deadline.clock_type)) !=
-            0 &&
-        !call->is_client) {
-      call->send_deadline =
-          gpr_convert_clock_type(md->deadline, GPR_CLOCK_MONOTONIC);
+    if (md->deadline != GRPC_MILLIS_INF_FUTURE && !call->is_client) {
+      call->send_deadline = md->deadline;
     }
   }
 
diff --git a/src/core/lib/surface/call.h b/src/core/lib/surface/call.h
index c680139cf6..27c2f5243c 100644
--- a/src/core/lib/surface/call.h
+++ b/src/core/lib/surface/call.h
@@ -49,7 +49,7 @@ typedef struct grpc_call_create_args {
   grpc_mdelem *add_initial_metadata;
   size_t add_initial_metadata_count;
 
-  gpr_timespec send_deadline;
+  grpc_millis send_deadline;
 } grpc_call_create_args;
 
 /* Create a new call based on \a args.
diff --git a/src/core/lib/surface/call_details.c b/src/core/lib/surface/call_details.cc
index ea9208c7e3..ea9208c7e3 100644
--- a/src/core/lib/surface/call_details.c
+++ b/src/core/lib/surface/call_details.cc
diff --git a/src/core/lib/surface/call_log_batch.c b/src/core/lib/surface/call_log_batch.cc
index 4a1c265817..5557927b7c 100644
--- a/src/core/lib/surface/call_log_batch.c
+++ b/src/core/lib/surface/call_log_batch.cc
@@ -18,6 +18,8 @@
 
 #include "src/core/lib/surface/call.h"
 
+#include <inttypes.h>
+
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 #include "src/core/lib/slice/slice_string_helpers.h"
diff --git a/src/core/lib/surface/channel.c b/src/core/lib/surface/channel.cc
index fc7d745463..b2395302f4 100644
--- a/src/core/lib/surface/channel.c
+++ b/src/core/lib/surface/channel.cc
@@ -18,6 +18,7 @@
 
 #include "src/core/lib/surface/channel.h"
 
+#include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -144,17 +145,15 @@ grpc_channel *grpc_channel_create_with_builder(
       channel->compression_options.default_level.level =
           (grpc_compression_level)grpc_channel_arg_get_integer(
               &args->args[i],
-              (grpc_integer_options){GRPC_COMPRESS_LEVEL_NONE,
-                                     GRPC_COMPRESS_LEVEL_NONE,
-                                     GRPC_COMPRESS_LEVEL_COUNT - 1});
+              {GRPC_COMPRESS_LEVEL_NONE, GRPC_COMPRESS_LEVEL_NONE,
+               GRPC_COMPRESS_LEVEL_COUNT - 1});
     } else if (0 == strcmp(args->args[i].key,
                            GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM)) {
       channel->compression_options.default_algorithm.is_set = true;
       channel->compression_options.default_algorithm.algorithm =
           (grpc_compression_algorithm)grpc_channel_arg_get_integer(
-              &args->args[i],
-              (grpc_integer_options){GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE,
-                                     GRPC_COMPRESS_ALGORITHMS_COUNT - 1});
+              &args->args[i], {GRPC_COMPRESS_NONE, GRPC_COMPRESS_NONE,
+                               GRPC_COMPRESS_ALGORITHMS_COUNT - 1});
     } else if (0 ==
                strcmp(args->args[i].key,
                       GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET)) {
@@ -236,7 +235,7 @@ static grpc_call *grpc_channel_create_call_internal(
     grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
     uint32_t propagation_mask, grpc_completion_queue *cq,
     grpc_pollset_set *pollset_set_alternative, grpc_mdelem path_mdelem,
-    grpc_mdelem authority_mdelem, gpr_timespec deadline) {
+    grpc_mdelem authority_mdelem, grpc_millis deadline) {
   grpc_mdelem send_metadata[2];
   size_t num_metadata = 0;
 
@@ -282,7 +281,7 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
       host != NULL ? grpc_mdelem_from_slices(&exec_ctx, GRPC_MDSTR_AUTHORITY,
                                              grpc_slice_ref_internal(*host))
                    : GRPC_MDNULL,
-      deadline);
+      grpc_timespec_to_millis_round_up(deadline));
   grpc_exec_ctx_finish(&exec_ctx);
   return call;
 }
@@ -290,7 +289,7 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
 grpc_call *grpc_channel_create_pollset_set_call(
     grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
     uint32_t propagation_mask, grpc_pollset_set *pollset_set, grpc_slice method,
-    const grpc_slice *host, gpr_timespec deadline, void *reserved) {
+    const grpc_slice *host, grpc_millis deadline, void *reserved) {
   GPR_ASSERT(!reserved);
   return grpc_channel_create_call_internal(
       exec_ctx, channel, parent_call, propagation_mask, NULL, pollset_set,
@@ -346,7 +345,8 @@ grpc_call *grpc_channel_create_registered_call(
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_call *call = grpc_channel_create_call_internal(
       &exec_ctx, channel, parent_call, propagation_mask, completion_queue, NULL,
-      GRPC_MDELEM_REF(rc->path), GRPC_MDELEM_REF(rc->authority), deadline);
+      GRPC_MDELEM_REF(rc->path), GRPC_MDELEM_REF(rc->authority),
+      grpc_timespec_to_millis_round_up(deadline));
   grpc_exec_ctx_finish(&exec_ctx);
   return call;
 }
diff --git a/src/core/lib/surface/channel.h b/src/core/lib/surface/channel.h
index 528bb868e2..4d1c7e369f 100644
--- a/src/core/lib/surface/channel.h
+++ b/src/core/lib/surface/channel.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/channel/channel_stack_builder.h"
 #include "src/core/lib/surface/channel_stack_type.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
                                   const grpc_channel_args *args,
                                   grpc_channel_stack_type channel_stack_type,
@@ -43,7 +47,7 @@ grpc_channel *grpc_channel_create_with_builder(
 grpc_call *grpc_channel_create_pollset_set_call(
     grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
     uint32_t propagation_mask, grpc_pollset_set *pollset_set, grpc_slice method,
-    const grpc_slice *host, gpr_timespec deadline, void *reserved);
+    const grpc_slice *host, grpc_millis deadline, void *reserved);
 
 /** Get a (borrowed) pointer to this channels underlying channel stack */
 grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel);
@@ -81,4 +85,8 @@ void grpc_channel_internal_unref(grpc_exec_ctx *exec_ctx,
 grpc_compression_options grpc_channel_compression_options(
     const grpc_channel *channel);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_H */
diff --git a/src/core/lib/surface/channel_init.c b/src/core/lib/surface/channel_init.cc
index 33f444b89e..33f444b89e 100644
--- a/src/core/lib/surface/channel_init.c
+++ b/src/core/lib/surface/channel_init.cc
diff --git a/src/core/lib/surface/channel_ping.c b/src/core/lib/surface/channel_ping.cc
index f45b568958..f45b568958 100644
--- a/src/core/lib/surface/channel_ping.c
+++ b/src/core/lib/surface/channel_ping.cc
diff --git a/src/core/lib/surface/channel_stack_type.c b/src/core/lib/surface/channel_stack_type.cc
index 5f5c877727..5f5c877727 100644
--- a/src/core/lib/surface/channel_stack_type.c
+++ b/src/core/lib/surface/channel_stack_type.cc
diff --git a/src/core/lib/surface/channel_stack_type.h b/src/core/lib/surface/channel_stack_type.h
index 3f0e14ffc0..903b90a071 100644
--- a/src/core/lib/surface/channel_stack_type.h
+++ b/src/core/lib/surface/channel_stack_type.h
@@ -21,6 +21,10 @@
 
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef enum {
   // normal top-half client channel with load-balancing, connection management
   GRPC_CLIENT_CHANNEL,
@@ -42,4 +46,8 @@ bool grpc_channel_stack_type_is_client(grpc_channel_stack_type type);
 
 const char *grpc_channel_stack_type_string(grpc_channel_stack_type type);
 
-#endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_STACK_TYPE_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_CHANNEL_STACK_TYPE_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.cc
index fed66e3a20..36b4b835f8 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.cc
@@ -15,8 +15,11 @@
  * limitations under the License.
  *
  */
+#include <grpc/support/port_platform.h>
+
 #include "src/core/lib/surface/completion_queue.h"
 
+#include <inttypes.h>
 #include <stdio.h>
 #include <string.h>
 
@@ -58,8 +61,7 @@ typedef struct {
   grpc_error *(*kick)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                       grpc_pollset_worker *specific_worker);
   grpc_error *(*work)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                      grpc_pollset_worker **worker, gpr_timespec now,
-                      gpr_timespec deadline);
+                      grpc_pollset_worker **worker, grpc_millis deadline);
   void (*shutdown)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                    grpc_closure *closure);
   void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset);
@@ -97,8 +99,7 @@ static void non_polling_poller_destroy(grpc_exec_ctx *exec_ctx,
 static grpc_error *non_polling_poller_work(grpc_exec_ctx *exec_ctx,
                                            grpc_pollset *pollset,
                                            grpc_pollset_worker **worker,
-                                           gpr_timespec now,
-                                           gpr_timespec deadline) {
+                                           grpc_millis deadline) {
   non_polling_poller *npp = (non_polling_poller *)pollset;
   if (npp->shutdown) return GRPC_ERROR_NONE;
   non_polling_worker w;
@@ -112,7 +113,10 @@ static grpc_error *non_polling_poller_work(grpc_exec_ctx *exec_ctx,
     w.next->prev = w.prev->next = &w;
   }
   w.kicked = false;
-  while (!npp->shutdown && !w.kicked && !gpr_cv_wait(&w.cv, &npp->mu, deadline))
+  gpr_timespec deadline_ts =
+      grpc_millis_to_timespec(deadline, GPR_CLOCK_REALTIME);
+  while (!npp->shutdown && !w.kicked &&
+         !gpr_cv_wait(&w.cv, &npp->mu, deadline_ts))
     ;
   if (&w == npp->root) {
     npp->root = w.next;
@@ -164,32 +168,15 @@ static void non_polling_poller_shutdown(grpc_exec_ctx *exec_ctx,
 
 static const cq_poller_vtable g_poller_vtable_by_poller_type[] = {
     /* GRPC_CQ_DEFAULT_POLLING */
-    {.can_get_pollset = true,
-     .can_listen = true,
-     .size = grpc_pollset_size,
-     .init = grpc_pollset_init,
-     .kick = grpc_pollset_kick,
-     .work = grpc_pollset_work,
-     .shutdown = grpc_pollset_shutdown,
-     .destroy = grpc_pollset_destroy},
+    {true, true, grpc_pollset_size, grpc_pollset_init, grpc_pollset_kick,
+     grpc_pollset_work, grpc_pollset_shutdown, grpc_pollset_destroy},
     /* GRPC_CQ_NON_LISTENING */
-    {.can_get_pollset = true,
-     .can_listen = false,
-     .size = grpc_pollset_size,
-     .init = grpc_pollset_init,
-     .kick = grpc_pollset_kick,
-     .work = grpc_pollset_work,
-     .shutdown = grpc_pollset_shutdown,
-     .destroy = grpc_pollset_destroy},
+    {true, false, grpc_pollset_size, grpc_pollset_init, grpc_pollset_kick,
+     grpc_pollset_work, grpc_pollset_shutdown, grpc_pollset_destroy},
     /* GRPC_CQ_NON_POLLING */
-    {.can_get_pollset = false,
-     .can_listen = false,
-     .size = non_polling_poller_size,
-     .init = non_polling_poller_init,
-     .kick = non_polling_poller_kick,
-     .work = non_polling_poller_work,
-     .shutdown = non_polling_poller_shutdown,
-     .destroy = non_polling_poller_destroy},
+    {false, false, non_polling_poller_size, non_polling_poller_init,
+     non_polling_poller_kick, non_polling_poller_work,
+     non_polling_poller_shutdown, non_polling_poller_destroy},
 };
 
 typedef struct cq_vtable {
@@ -757,7 +744,7 @@ void grpc_cq_end_op(grpc_exec_ctx *exec_ctx, grpc_completion_queue *cq,
 typedef struct {
   gpr_atm last_seen_things_queued_ever;
   grpc_completion_queue *cq;
-  gpr_timespec deadline;
+  grpc_millis deadline;
   grpc_cq_completion *stolen_completion;
   void *tag; /* for pluck */
   bool first_loop;
@@ -786,8 +773,7 @@ static bool cq_is_next_finished(grpc_exec_ctx *exec_ctx, void *arg) {
       return true;
     }
   }
-  return !a->first_loop &&
-         gpr_time_cmp(a->deadline, gpr_now(a->deadline.clock_type)) < 0;
+  return !a->first_loop && a->deadline < grpc_exec_ctx_now(exec_ctx);
 }
 
 #ifndef NDEBUG
@@ -816,7 +802,6 @@ static void dump_pending_tags(grpc_completion_queue *cq) {}
 static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
                           void *reserved) {
   grpc_event ret;
-  gpr_timespec now;
   cq_next_data *cqd = (cq_next_data *)DATA_FROM_CQ(cq);
 
   GPR_TIMER_BEGIN("grpc_completion_queue_next", 0);
@@ -833,23 +818,20 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
 
   dump_pending_tags(cq);
 
-  deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
-
   GRPC_CQ_INTERNAL_REF(cq, "next");
 
+  grpc_millis deadline_millis = grpc_timespec_to_millis_round_up(deadline);
   cq_is_finished_arg is_finished_arg = {
-      .last_seen_things_queued_ever =
-          gpr_atm_no_barrier_load(&cqd->things_queued_ever),
-      .cq = cq,
-      .deadline = deadline,
-      .stolen_completion = NULL,
-      .tag = NULL,
-      .first_loop = true};
+      gpr_atm_no_barrier_load(&cqd->things_queued_ever),
+      cq,
+      deadline_millis,
+      NULL,
+      NULL,
+      true};
   grpc_exec_ctx exec_ctx =
       GRPC_EXEC_CTX_INITIALIZER(0, cq_is_next_finished, &is_finished_arg);
-
   for (;;) {
-    gpr_timespec iteration_deadline = deadline;
+    grpc_millis iteration_deadline = deadline_millis;
 
     if (is_finished_arg.stolen_completion != NULL) {
       grpc_cq_completion *c = is_finished_arg.stolen_completion;
@@ -876,7 +858,7 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
          attempt at popping. Not doing this can potentially deadlock this
          thread forever (if the deadline is infinity) */
       if (cq_event_queue_num_items(&cqd->queue) > 0) {
-        iteration_deadline = gpr_time_0(GPR_CLOCK_MONOTONIC);
+        iteration_deadline = 0;
       }
     }
 
@@ -897,8 +879,8 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
       break;
     }
 
-    now = gpr_now(GPR_CLOCK_MONOTONIC);
-    if (!is_finished_arg.first_loop && gpr_time_cmp(now, deadline) >= 0) {
+    if (!is_finished_arg.first_loop &&
+        grpc_exec_ctx_now(&exec_ctx) >= deadline_millis) {
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       dump_pending_tags(cq);
@@ -909,7 +891,7 @@ static grpc_event cq_next(grpc_completion_queue *cq, gpr_timespec deadline,
     gpr_mu_lock(cq->mu);
     cq->num_polls++;
     grpc_error *err = cq->poller_vtable->work(&exec_ctx, POLLSET_FROM_CQ(cq),
-                                              NULL, now, iteration_deadline);
+                                              NULL, iteration_deadline);
     gpr_mu_unlock(cq->mu);
 
     if (err != GRPC_ERROR_NONE) {
@@ -1046,8 +1028,7 @@ static bool cq_is_pluck_finished(grpc_exec_ctx *exec_ctx, void *arg) {
     }
     gpr_mu_unlock(cq->mu);
   }
-  return !a->first_loop &&
-         gpr_time_cmp(a->deadline, gpr_now(a->deadline.clock_type)) < 0;
+  return !a->first_loop && a->deadline < grpc_exec_ctx_now(exec_ctx);
 }
 
 static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
@@ -1056,7 +1037,6 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
   grpc_cq_completion *c;
   grpc_cq_completion *prev;
   grpc_pollset_worker *worker = NULL;
-  gpr_timespec now;
   cq_pluck_data *cqd = (cq_pluck_data *)DATA_FROM_CQ(cq);
 
   GPR_TIMER_BEGIN("grpc_completion_queue_pluck", 0);
@@ -1075,18 +1055,16 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
 
   dump_pending_tags(cq);
 
-  deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
-
   GRPC_CQ_INTERNAL_REF(cq, "pluck");
   gpr_mu_lock(cq->mu);
+  grpc_millis deadline_millis = grpc_timespec_to_millis_round_up(deadline);
   cq_is_finished_arg is_finished_arg = {
-      .last_seen_things_queued_ever =
-          gpr_atm_no_barrier_load(&cqd->things_queued_ever),
-      .cq = cq,
-      .deadline = deadline,
-      .stolen_completion = NULL,
-      .tag = tag,
-      .first_loop = true};
+      gpr_atm_no_barrier_load(&cqd->things_queued_ever),
+      cq,
+      deadline_millis,
+      NULL,
+      tag,
+      true};
   grpc_exec_ctx exec_ctx =
       GRPC_EXEC_CTX_INITIALIZER(0, cq_is_pluck_finished, &is_finished_arg);
   for (;;) {
@@ -1135,8 +1113,8 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
       dump_pending_tags(cq);
       break;
     }
-    now = gpr_now(GPR_CLOCK_MONOTONIC);
-    if (!is_finished_arg.first_loop && gpr_time_cmp(now, deadline) >= 0) {
+    if (!is_finished_arg.first_loop &&
+        grpc_exec_ctx_now(&exec_ctx) >= deadline_millis) {
       del_plucker(cq, tag, &worker);
       gpr_mu_unlock(cq->mu);
       memset(&ret, 0, sizeof(ret));
@@ -1144,10 +1122,9 @@ static grpc_event cq_pluck(grpc_completion_queue *cq, void *tag,
       dump_pending_tags(cq);
       break;
     }
-
     cq->num_polls++;
     grpc_error *err = cq->poller_vtable->work(&exec_ctx, POLLSET_FROM_CQ(cq),
-                                              &worker, now, deadline);
+                                              &worker, deadline_millis);
     if (err != GRPC_ERROR_NONE) {
       del_plucker(cq, tag, &worker);
       gpr_mu_unlock(cq->mu);
diff --git a/src/core/lib/surface/completion_queue_factory.c b/src/core/lib/surface/completion_queue_factory.cc
index aeecff5306..aeecff5306 100644
--- a/src/core/lib/surface/completion_queue_factory.c
+++ b/src/core/lib/surface/completion_queue_factory.cc
diff --git a/src/core/lib/surface/completion_queue_factory.h b/src/core/lib/surface/completion_queue_factory.h
index 89be8f8216..cb0af6f0fb 100644
--- a/src/core/lib/surface/completion_queue_factory.h
+++ b/src/core/lib/surface/completion_queue_factory.h
@@ -22,6 +22,10 @@
 #include <grpc/grpc.h>
 #include "src/core/lib/surface/completion_queue.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_completion_queue_factory_vtable {
   grpc_completion_queue* (*create)(const grpc_completion_queue_factory*,
                                    const grpc_completion_queue_attributes*);
@@ -33,4 +37,8 @@ struct grpc_completion_queue_factory {
   grpc_completion_queue_factory_vtable* vtable;
 };
 
-#endif /* GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_FACTORY_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_COMPLETION_QUEUE_FACTORY_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/event_string.c b/src/core/lib/surface/event_string.cc
index f236272e2a..f236272e2a 100644
--- a/src/core/lib/surface/event_string.c
+++ b/src/core/lib/surface/event_string.cc
diff --git a/src/core/lib/surface/event_string.h b/src/core/lib/surface/event_string.h
index f00efca7f3..127609c404 100644
--- a/src/core/lib/surface/event_string.h
+++ b/src/core/lib/surface/event_string.h
@@ -21,7 +21,15 @@
 
 #include <grpc/grpc.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Returns a string describing an event. Must be later freed with gpr_free() */
 char *grpc_event_string(grpc_event *ev);
 
-#endif /* GRPC_CORE_LIB_SURFACE_EVENT_STRING_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_EVENT_STRING_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.cc
index b089da2c54..b089da2c54 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.cc
diff --git a/src/core/lib/surface/init.h b/src/core/lib/surface/init.h
index 9353208332..b2f48576e5 100644
--- a/src/core/lib/surface/init.h
+++ b/src/core/lib/surface/init.h
@@ -19,9 +19,17 @@
 #ifndef GRPC_CORE_LIB_SURFACE_INIT_H
 #define GRPC_CORE_LIB_SURFACE_INIT_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void grpc_register_security_filters(void);
 void grpc_security_pre_init(void);
 void grpc_security_init(void);
 int grpc_is_initialized(void);
 
-#endif /* GRPC_CORE_LIB_SURFACE_INIT_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_INIT_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/init_secure.c b/src/core/lib/surface/init_secure.cc
index 2366c24910..8fbde3d1b4 100644
--- a/src/core/lib/surface/init_secure.c
+++ b/src/core/lib/surface/init_secure.cc
@@ -25,6 +25,7 @@
 
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/security/credentials/credentials.h"
+#include "src/core/lib/security/credentials/plugin/plugin_credentials.h"
 #include "src/core/lib/security/transport/auth_filters.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
 #include "src/core/lib/security/transport/security_connector.h"
@@ -84,4 +85,7 @@ void grpc_register_security_filters(void) {
                                    maybe_prepend_server_auth_filter, NULL);
 }
 
-void grpc_security_init() { grpc_security_register_handshaker_factories(); }
+void grpc_security_init() {
+  grpc_security_register_handshaker_factories();
+  grpc_register_tracer(&grpc_plugin_credentials_trace);
+}
diff --git a/src/core/lib/surface/init_unsecure.c b/src/core/lib/surface/init_unsecure.cc
index b852cab985..b852cab985 100644
--- a/src/core/lib/surface/init_unsecure.c
+++ b/src/core/lib/surface/init_unsecure.cc
diff --git a/src/core/lib/surface/lame_client.cc b/src/core/lib/surface/lame_client.cc
index 6286f9159d..88e26cbeb7 100644
--- a/src/core/lib/surface/lame_client.cc
+++ b/src/core/lib/surface/lame_client.cc
@@ -74,7 +74,7 @@ static void fill_metadata(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   mdb->list.head = &calld->status;
   mdb->list.tail = &calld->details;
   mdb->list.count = 2;
-  mdb->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
+  mdb->deadline = GRPC_MILLIS_INF_FUTURE;
 }
 
 static void lame_start_transport_stream_op_batch(
diff --git a/src/core/lib/surface/lame_client.h b/src/core/lib/surface/lame_client.h
index 3ce353f101..2f6f9cd046 100644
--- a/src/core/lib/surface/lame_client.h
+++ b/src/core/lib/surface/lame_client.h
@@ -21,6 +21,14 @@
 
 #include "src/core/lib/channel/channel_stack.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_lame_filter;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_LAME_CLIENT_H */
diff --git a/src/core/lib/surface/metadata_array.c b/src/core/lib/surface/metadata_array.cc
index 0afb8b4b87..0afb8b4b87 100644
--- a/src/core/lib/surface/metadata_array.c
+++ b/src/core/lib/surface/metadata_array.cc
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.cc
index 1d0fd472d0..dd09cb91de 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.cc
@@ -137,7 +137,7 @@ struct call_data {
   bool host_set;
   grpc_slice path;
   grpc_slice host;
-  gpr_timespec deadline;
+  grpc_millis deadline;
 
   grpc_completion_queue *cq_new;
 
@@ -492,11 +492,13 @@ static void publish_call(grpc_exec_ctx *exec_ctx, grpc_server *server,
       GPR_ASSERT(calld->path_set);
       rc->data.batch.details->host = grpc_slice_ref_internal(calld->host);
       rc->data.batch.details->method = grpc_slice_ref_internal(calld->path);
-      rc->data.batch.details->deadline = calld->deadline;
+      rc->data.batch.details->deadline =
+          grpc_millis_to_timespec(calld->deadline, GPR_CLOCK_MONOTONIC);
       rc->data.batch.details->flags = calld->recv_initial_metadata_flags;
       break;
     case REGISTERED_CALL:
-      *rc->data.registered.deadline = calld->deadline;
+      *rc->data.registered.deadline =
+          grpc_millis_to_timespec(calld->deadline, GPR_CLOCK_MONOTONIC);
       if (rc->data.registered.optional_payload) {
         *rc->data.registered.optional_payload = calld->payload;
         calld->payload = NULL;
@@ -739,7 +741,7 @@ static void server_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx, void *ptr,
                                             grpc_error *error) {
   grpc_call_element *elem = (grpc_call_element *)ptr;
   call_data *calld = (call_data *)elem->call_data;
-  gpr_timespec op_deadline;
+  grpc_millis op_deadline;
 
   if (error == GRPC_ERROR_NONE) {
     GPR_ASSERT(calld->recv_initial_metadata->idx.named.path != NULL);
@@ -759,7 +761,7 @@ static void server_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx, void *ptr,
     GRPC_ERROR_REF(error);
   }
   op_deadline = calld->recv_initial_metadata->deadline;
-  if (0 != gpr_time_cmp(op_deadline, gpr_inf_future(op_deadline.clock_type))) {
+  if (op_deadline != GRPC_MILLIS_INF_FUTURE) {
     calld->deadline = op_deadline;
   }
   if (calld->host_set && calld->path_set) {
@@ -833,7 +835,7 @@ static void accept_stream(grpc_exec_ctx *exec_ctx, void *cd,
   memset(&args, 0, sizeof(args));
   args.channel = chand->channel;
   args.server_transport_data = transport_server_data;
-  args.send_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+  args.send_deadline = GRPC_MILLIS_INF_FUTURE;
   grpc_call *call;
   grpc_error *error = grpc_call_create(exec_ctx, &args, &call);
   grpc_call_element *elem =
@@ -881,7 +883,7 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   call_data *calld = (call_data *)elem->call_data;
   channel_data *chand = (channel_data *)elem->channel_data;
   memset(calld, 0, sizeof(call_data));
-  calld->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
+  calld->deadline = GRPC_MILLIS_INF_FUTURE;
   calld->call = grpc_call_from_top_element(elem);
   gpr_mu_init(&calld->mu_state);
 
diff --git a/src/core/lib/surface/server.h b/src/core/lib/surface/server.h
index dd5639d97a..1114715833 100644
--- a/src/core/lib/surface/server.h
+++ b/src/core/lib/surface/server.h
@@ -24,6 +24,10 @@
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/transport/transport.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_server_top_filter;
 
 /** Lightweight tracing of server channel state */
@@ -54,4 +58,8 @@ int grpc_server_has_open_connections(grpc_server *server);
 void grpc_server_get_pollsets(grpc_server *server, grpc_pollset ***pollsets,
                               size_t *pollset_count);
 
-#endif /* GRPC_CORE_LIB_SURFACE_SERVER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_SERVER_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/validate_metadata.c b/src/core/lib/surface/validate_metadata.cc
index 61209ae48d..81d07fae44 100644
--- a/src/core/lib/surface/validate_metadata.c
+++ b/src/core/lib/surface/validate_metadata.cc
@@ -26,6 +26,7 @@
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/surface/validate_metadata.h"
 
 static grpc_error *conforms_to(grpc_slice slice, const uint8_t *legal_bits,
                                const char *err_desc) {
diff --git a/src/core/lib/surface/validate_metadata.h b/src/core/lib/surface/validate_metadata.h
index de869d89b4..aa02419d9f 100644
--- a/src/core/lib/surface/validate_metadata.h
+++ b/src/core/lib/surface/validate_metadata.h
@@ -22,7 +22,15 @@
 #include <grpc/slice.h>
 #include "src/core/lib/iomgr/error.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 grpc_error *grpc_validate_header_key_is_legal(grpc_slice slice);
 grpc_error *grpc_validate_header_nonbin_value_is_legal(grpc_slice slice);
 
-#endif /* GRPC_CORE_LIB_SURFACE_VALIDATE_METADATA_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_SURFACE_VALIDATE_METADATA_H */
\ No newline at end of file
diff --git a/src/core/lib/surface/version.c b/src/core/lib/surface/version.cc
index fd6ea4daa9..6cb8e7e1a0 100644
--- a/src/core/lib/surface/version.c
+++ b/src/core/lib/surface/version.cc
@@ -23,4 +23,4 @@
 
 const char *grpc_version_string(void) { return "5.0.0-dev"; }
 
-const char *grpc_g_stands_for(void) { return "gambit"; }
+const char *grpc_g_stands_for(void) { return "generous"; }
diff --git a/src/core/lib/transport/bdp_estimator.c b/src/core/lib/transport/bdp_estimator.cc
index 8b57693413..6ed427ce5c 100644
--- a/src/core/lib/transport/bdp_estimator.c
+++ b/src/core/lib/transport/bdp_estimator.cc
@@ -18,6 +18,7 @@
 
 #include "src/core/lib/transport/bdp_estimator.h"
 
+#include <inttypes.h>
 #include <stdlib.h>
 
 #include <grpc/support/log.h>
@@ -29,8 +30,12 @@ grpc_tracer_flag grpc_bdp_estimator_trace =
 void grpc_bdp_estimator_init(grpc_bdp_estimator *estimator, const char *name) {
   estimator->estimate = 65536;
   estimator->ping_state = GRPC_BDP_PING_UNSCHEDULED;
+  estimator->ping_start_time = gpr_time_0(GPR_CLOCK_MONOTONIC);
+  estimator->next_ping_scheduled = 0;
   estimator->name = name;
   estimator->bw_est = 0;
+  estimator->inter_ping_delay = 100.0;  // start at 100ms
+  estimator->stable_estimate_count = 0;
 }
 
 bool grpc_bdp_estimator_get_estimate(const grpc_bdp_estimator *estimator,
@@ -50,10 +55,11 @@ void grpc_bdp_estimator_add_incoming_bytes(grpc_bdp_estimator *estimator,
   estimator->accumulator += num_bytes;
 }
 
-bool grpc_bdp_estimator_need_ping(const grpc_bdp_estimator *estimator) {
+bool grpc_bdp_estimator_need_ping(grpc_exec_ctx *exec_ctx,
+                                  const grpc_bdp_estimator *estimator) {
   switch (estimator->ping_state) {
     case GRPC_BDP_PING_UNSCHEDULED:
-      return true;
+      return grpc_exec_ctx_now(exec_ctx) >= estimator->next_ping_scheduled;
     case GRPC_BDP_PING_SCHEDULED:
       return false;
     case GRPC_BDP_PING_STARTED:
@@ -83,11 +89,13 @@ void grpc_bdp_estimator_start_ping(grpc_bdp_estimator *estimator) {
   estimator->ping_start_time = gpr_now(GPR_CLOCK_MONOTONIC);
 }
 
-void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator) {
-  gpr_timespec dt_ts =
-      gpr_time_sub(gpr_now(GPR_CLOCK_MONOTONIC), estimator->ping_start_time);
+void grpc_bdp_estimator_complete_ping(grpc_exec_ctx *exec_ctx,
+                                      grpc_bdp_estimator *estimator) {
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+  gpr_timespec dt_ts = gpr_time_sub(now, estimator->ping_start_time);
   double dt = (double)dt_ts.tv_sec + 1e-9 * (double)dt_ts.tv_nsec;
   double bw = dt > 0 ? ((double)estimator->accumulator / dt) : 0;
+  int start_inter_ping_delay = estimator->inter_ping_delay;
   if (GRPC_TRACER_ON(grpc_bdp_estimator_trace)) {
     gpr_log(GPR_DEBUG, "bdp[%s]:complete acc=%" PRId64 " est=%" PRId64
                        " dt=%lf bw=%lfMbs bw_est=%lfMbs",
@@ -104,7 +112,26 @@ void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator) {
       gpr_log(GPR_DEBUG, "bdp[%s]: estimate increased to %" PRId64,
               estimator->name, estimator->estimate);
     }
+    estimator->inter_ping_delay /= 2;  // if the ping estimate changes,
+                                       // exponentially get faster at probing
+  } else if (estimator->inter_ping_delay < 10000) {
+    estimator->stable_estimate_count++;
+    if (estimator->stable_estimate_count >= 2) {
+      estimator->inter_ping_delay +=
+          100 +
+          (int)(rand() * 100.0 / RAND_MAX);  // if the ping estimate is steady,
+                                             // slowly ramp down the probe time
+    }
+  }
+  if (start_inter_ping_delay != estimator->inter_ping_delay) {
+    estimator->stable_estimate_count = 0;
+    if (GRPC_TRACER_ON(grpc_bdp_estimator_trace)) {
+      gpr_log(GPR_DEBUG, "bdp[%s]:update_inter_time to %dms", estimator->name,
+              estimator->inter_ping_delay);
+    }
   }
   estimator->ping_state = GRPC_BDP_PING_UNSCHEDULED;
   estimator->accumulator = 0;
+  estimator->next_ping_scheduled =
+      grpc_exec_ctx_now(exec_ctx) + estimator->inter_ping_delay;
 }
diff --git a/src/core/lib/transport/bdp_estimator.h b/src/core/lib/transport/bdp_estimator.h
index 1ef0dc99dd..480d5237b8 100644
--- a/src/core/lib/transport/bdp_estimator.h
+++ b/src/core/lib/transport/bdp_estimator.h
@@ -23,10 +23,15 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 
 #define GRPC_BDP_SAMPLES 16
 #define GRPC_BDP_MIN_SAMPLES_FOR_ESTIMATE 3
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_tracer_flag grpc_bdp_estimator_trace;
 
 typedef enum {
@@ -39,7 +44,12 @@ typedef struct grpc_bdp_estimator {
   grpc_bdp_estimator_ping_state ping_state;
   int64_t accumulator;
   int64_t estimate;
+  // when was the current ping started?
   gpr_timespec ping_start_time;
+  // when should the next ping start?
+  grpc_millis next_ping_scheduled;
+  int inter_ping_delay;
+  int stable_estimate_count;
   double bw_est;
   const char *name;
 } grpc_bdp_estimator;
@@ -55,7 +65,8 @@ bool grpc_bdp_estimator_get_bw(const grpc_bdp_estimator *estimator, double *bw);
 void grpc_bdp_estimator_add_incoming_bytes(grpc_bdp_estimator *estimator,
                                            int64_t num_bytes);
 // Returns true if the user should schedule a ping
-bool grpc_bdp_estimator_need_ping(const grpc_bdp_estimator *estimator);
+bool grpc_bdp_estimator_need_ping(grpc_exec_ctx *exec_ctx,
+                                  const grpc_bdp_estimator *estimator);
 // Schedule a ping: call in response to receiving a true from
 // grpc_bdp_estimator_add_incoming_bytes once a ping has been scheduled by a
 // transport (but not necessarily started)
@@ -64,6 +75,11 @@ void grpc_bdp_estimator_schedule_ping(grpc_bdp_estimator *estimator);
 // the ping is on the wire
 void grpc_bdp_estimator_start_ping(grpc_bdp_estimator *estimator);
 // Completes a previously started ping
-void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator);
+void grpc_bdp_estimator_complete_ping(grpc_exec_ctx *exec_ctx,
+                                      grpc_bdp_estimator *estimator);
+
+#ifdef __cplusplus
+}
+#endif
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H */
+#endif /* GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/byte_stream.c b/src/core/lib/transport/byte_stream.cc
index 08f61629a9..08f61629a9 100644
--- a/src/core/lib/transport/byte_stream.c
+++ b/src/core/lib/transport/byte_stream.cc
diff --git a/src/core/lib/transport/byte_stream.h b/src/core/lib/transport/byte_stream.h
index be2a35213e..d3e04df5c0 100644
--- a/src/core/lib/transport/byte_stream.h
+++ b/src/core/lib/transport/byte_stream.h
@@ -28,6 +28,10 @@
 /** Mask of all valid internal flags. */
 #define GRPC_WRITE_INTERNAL_USED_MASK (GRPC_WRITE_INTERNAL_COMPRESS)
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_byte_stream grpc_byte_stream;
 
 typedef struct {
@@ -135,4 +139,8 @@ void grpc_caching_byte_stream_init(grpc_caching_byte_stream *stream,
 // Resets the byte stream to the start of the underlying stream.
 void grpc_caching_byte_stream_reset(grpc_caching_byte_stream *stream);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_BYTE_STREAM_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/connectivity_state.c b/src/core/lib/transport/connectivity_state.cc
index f328a6cdbb..f328a6cdbb 100644
--- a/src/core/lib/transport/connectivity_state.c
+++ b/src/core/lib/transport/connectivity_state.cc
diff --git a/src/core/lib/transport/connectivity_state.h b/src/core/lib/transport/connectivity_state.h
index 2fece6cc21..1796a540a7 100644
--- a/src/core/lib/transport/connectivity_state.h
+++ b/src/core/lib/transport/connectivity_state.h
@@ -23,6 +23,10 @@
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_connectivity_state_watcher {
   /** we keep watchers in a linked list */
   struct grpc_connectivity_state_watcher *next;
@@ -84,4 +88,8 @@ bool grpc_connectivity_state_notify_on_state_change(
     grpc_exec_ctx *exec_ctx, grpc_connectivity_state_tracker *tracker,
     grpc_connectivity_state *current, grpc_closure *notify);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_CONNECTIVITY_STATE_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_CONNECTIVITY_STATE_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/error_utils.c b/src/core/lib/transport/error_utils.cc
index 5e3920b627..2e3b61b7ab 100644
--- a/src/core/lib/transport/error_utils.c
+++ b/src/core/lib/transport/error_utils.cc
@@ -39,8 +39,9 @@ static grpc_error *recursively_find_error_with_field(grpc_error *error,
   return NULL;
 }
 
-void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
-                           grpc_status_code *code, grpc_slice *slice,
+void grpc_error_get_status(grpc_exec_ctx *exec_ctx, grpc_error *error,
+                           grpc_millis deadline, grpc_status_code *code,
+                           grpc_slice *slice,
                            grpc_http2_error_code *http_error) {
   // Start with the parent error and recurse through the tree of children
   // until we find the first one that has a status code.
@@ -63,8 +64,8 @@ void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
     status = (grpc_status_code)integer;
   } else if (grpc_error_get_int(found_error, GRPC_ERROR_INT_HTTP2_ERROR,
                                 &integer)) {
-    status = grpc_http2_error_to_grpc_status((grpc_http2_error_code)integer,
-                                             deadline);
+    status = grpc_http2_error_to_grpc_status(
+        exec_ctx, (grpc_http2_error_code)integer, deadline);
   }
   if (code != NULL) *code = status;
 
diff --git a/src/core/lib/transport/error_utils.h b/src/core/lib/transport/error_utils.h
index e530884215..2c97f9f0bc 100644
--- a/src/core/lib/transport/error_utils.h
+++ b/src/core/lib/transport/error_utils.h
@@ -20,16 +20,22 @@
 #define GRPC_CORE_LIB_TRANSPORT_ERROR_UTILS_H
 
 #include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/transport/http2_errors.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /// A utility function to get the status code and message to be returned
 /// to the application.  If not set in the top-level message, looks
 /// through child errors until it finds the first one with these attributes.
 /// All attributes are pulled from the same child error. If any of the
 /// attributes (code, msg, http_status) are unneeded, they can be passed as
 /// NULL.
-void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
-                           grpc_status_code *code, grpc_slice *slice,
+void grpc_error_get_status(grpc_exec_ctx *exec_ctx, grpc_error *error,
+                           grpc_millis deadline, grpc_status_code *code,
+                           grpc_slice *slice,
                            grpc_http2_error_code *http_status);
 
 /// A utility function to check whether there is a clear status code that
@@ -38,4 +44,8 @@ void grpc_error_get_status(grpc_error *error, gpr_timespec deadline,
 /// GRPC_ERROR_CANCELLED
 bool grpc_error_has_clear_grpc_status(grpc_error *error);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_ERROR_UTILS_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_ERROR_UTILS_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/metadata.c b/src/core/lib/transport/metadata.cc
index 188b485625..5455b2481b 100644
--- a/src/core/lib/transport/metadata.c
+++ b/src/core/lib/transport/metadata.cc
@@ -19,6 +19,7 @@
 #include "src/core/lib/transport/metadata.h"
 
 #include <assert.h>
+#include <inttypes.h>
 #include <stddef.h>
 #include <string.h>
 
diff --git a/src/core/lib/transport/metadata.h b/src/core/lib/transport/metadata.h
index 974469e436..9f82225dc3 100644
--- a/src/core/lib/transport/metadata.h
+++ b/src/core/lib/transport/metadata.h
@@ -102,8 +102,13 @@ struct grpc_mdelem {
   ((grpc_mdelem_data *)((md).payload & ~(uintptr_t)3))
 #define GRPC_MDELEM_STORAGE(md) \
   ((grpc_mdelem_data_storage)((md).payload & (uintptr_t)3))
+#ifdef __cplusplus
+#define GRPC_MAKE_MDELEM(data, storage) \
+  (grpc_mdelem{((uintptr_t)(data)) | ((uintptr_t)storage)})
+#else
 #define GRPC_MAKE_MDELEM(data, storage) \
   ((grpc_mdelem){((uintptr_t)(data)) | ((uintptr_t)storage)})
+#endif
 #define GRPC_MDELEM_IS_INTERNED(md)          \
   ((grpc_mdelem_data_storage)((md).payload & \
                               (uintptr_t)GRPC_MDELEM_STORAGE_INTERNED_BIT))
diff --git a/src/core/lib/transport/metadata_batch.c b/src/core/lib/transport/metadata_batch.cc
index 54388bdcda..2df9c9189c 100644
--- a/src/core/lib/transport/metadata_batch.c
+++ b/src/core/lib/transport/metadata_batch.cc
@@ -74,7 +74,7 @@ void grpc_metadata_batch_assert_ok(grpc_metadata_batch *batch) {
 
 void grpc_metadata_batch_init(grpc_metadata_batch *batch) {
   memset(batch, 0, sizeof(*batch));
-  batch->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
+  batch->deadline = GRPC_MILLIS_INF_FUTURE;
 }
 
 void grpc_metadata_batch_destroy(grpc_exec_ctx *exec_ctx,
@@ -270,9 +270,7 @@ void grpc_metadata_batch_clear(grpc_exec_ctx *exec_ctx,
 }
 
 bool grpc_metadata_batch_is_empty(grpc_metadata_batch *batch) {
-  return batch->list.head == NULL &&
-         gpr_time_cmp(gpr_inf_future(batch->deadline.clock_type),
-                      batch->deadline) == 0;
+  return batch->list.head == NULL && batch->deadline == GRPC_MILLIS_INF_FUTURE;
 }
 
 size_t grpc_metadata_batch_size(grpc_metadata_batch *batch) {
diff --git a/src/core/lib/transport/metadata_batch.h b/src/core/lib/transport/metadata_batch.h
index 57d298c75c..a2b4b92385 100644
--- a/src/core/lib/transport/metadata_batch.h
+++ b/src/core/lib/transport/metadata_batch.h
@@ -51,9 +51,9 @@ typedef struct grpc_metadata_batch {
   grpc_mdelem_list list;
   grpc_metadata_batch_callouts idx;
   /** Used to calculate grpc-timeout at the point of sending,
-      or gpr_inf_future if this batch does not need to send a
+      or GRPC_MILLIS_INF_FUTURE if this batch does not need to send a
       grpc-timeout */
-  gpr_timespec deadline;
+  grpc_millis deadline;
 } grpc_metadata_batch;
 
 void grpc_metadata_batch_init(grpc_metadata_batch *batch);
@@ -125,10 +125,11 @@ typedef struct {
 } grpc_filtered_mdelem;
 
 #define GRPC_FILTERED_ERROR(error) \
-  ((grpc_filtered_mdelem){(error), GRPC_MDNULL})
-#define GRPC_FILTERED_MDELEM(md) ((grpc_filtered_mdelem){GRPC_ERROR_NONE, (md)})
+  { (error), GRPC_MDNULL }
+#define GRPC_FILTERED_MDELEM(md) \
+  { GRPC_ERROR_NONE, (md) }
 #define GRPC_FILTERED_REMOVE() \
-  ((grpc_filtered_mdelem){GRPC_ERROR_NONE, GRPC_MDNULL})
+  { GRPC_ERROR_NONE, GRPC_MDNULL }
 
 typedef grpc_filtered_mdelem (*grpc_metadata_batch_filter_func)(
     grpc_exec_ctx *exec_ctx, void *user_data, grpc_mdelem elem);
diff --git a/src/core/lib/transport/pid_controller.c b/src/core/lib/transport/pid_controller.cc
index 4b304f17b2..4b304f17b2 100644
--- a/src/core/lib/transport/pid_controller.c
+++ b/src/core/lib/transport/pid_controller.cc
diff --git a/src/core/lib/transport/pid_controller.h b/src/core/lib/transport/pid_controller.h
index 9352b2643f..17feabfd39 100644
--- a/src/core/lib/transport/pid_controller.h
+++ b/src/core/lib/transport/pid_controller.h
@@ -19,6 +19,10 @@
 #ifndef GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H
 #define GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* \file Simple PID controller.
    Implements a proportional-integral-derivative controller.
    Used when we want to iteratively control a variable to converge some other
@@ -59,4 +63,8 @@ double grpc_pid_controller_update(grpc_pid_controller *pid_controller,
 /** Returns the last control value calculated */
 double grpc_pid_controller_last(grpc_pid_controller *pid_controller);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/service_config.c b/src/core/lib/transport/service_config.cc
index 070a13a2b4..070a13a2b4 100644
--- a/src/core/lib/transport/service_config.c
+++ b/src/core/lib/transport/service_config.cc
diff --git a/src/core/lib/transport/service_config.h b/src/core/lib/transport/service_config.h
index 84110abc36..c485f52472 100644
--- a/src/core/lib/transport/service_config.h
+++ b/src/core/lib/transport/service_config.h
@@ -22,6 +22,10 @@
 #include "src/core/lib/json/json.h"
 #include "src/core/lib/slice/slice_hash_table.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_service_config grpc_service_config;
 
 grpc_service_config* grpc_service_config_create(const char* json_string);
@@ -59,4 +63,8 @@ void* grpc_method_config_table_get(grpc_exec_ctx* exec_ctx,
                                    const grpc_slice_hash_table* table,
                                    grpc_slice path);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_SERVICE_CONFIG_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_SERVICE_CONFIG_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/static_metadata.c b/src/core/lib/transport/static_metadata.cc
index 8edb3bbbd0..8edb3bbbd0 100644
--- a/src/core/lib/transport/static_metadata.c
+++ b/src/core/lib/transport/static_metadata.cc
diff --git a/src/core/lib/transport/static_metadata.h b/src/core/lib/transport/static_metadata.h
index 9c5504e299..6b535acebd 100644
--- a/src/core/lib/transport/static_metadata.h
+++ b/src/core/lib/transport/static_metadata.h
@@ -27,6 +27,10 @@
 #ifndef GRPC_CORE_LIB_TRANSPORT_STATIC_METADATA_H
 #define GRPC_CORE_LIB_TRANSPORT_STATIC_METADATA_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "src/core/lib/transport/metadata.h"
 
 #define GRPC_STATIC_MDSTR_COUNT 101
@@ -586,4 +590,7 @@ extern const uint8_t grpc_static_accept_stream_encoding_metadata[4];
   (GRPC_MAKE_MDELEM(&grpc_static_mdelem_table                                  \
                         [grpc_static_accept_stream_encoding_metadata[(algs)]], \
                     GRPC_MDELEM_STORAGE_STATIC))
+#ifdef __cplusplus
+}
+#endif
 #endif /* GRPC_CORE_LIB_TRANSPORT_STATIC_METADATA_H */
diff --git a/src/core/lib/transport/status_conversion.c b/src/core/lib/transport/status_conversion.cc
index a40d333284..891c4427d7 100644
--- a/src/core/lib/transport/status_conversion.c
+++ b/src/core/lib/transport/status_conversion.cc
@@ -37,8 +37,9 @@ grpc_http2_error_code grpc_status_to_http2_error(grpc_status_code status) {
   }
 }
 
-grpc_status_code grpc_http2_error_to_grpc_status(grpc_http2_error_code error,
-                                                 gpr_timespec deadline) {
+grpc_status_code grpc_http2_error_to_grpc_status(grpc_exec_ctx *exec_ctx,
+                                                 grpc_http2_error_code error,
+                                                 grpc_millis deadline) {
   switch (error) {
     case GRPC_HTTP2_NO_ERROR:
       /* should never be received */
@@ -46,7 +47,7 @@ grpc_status_code grpc_http2_error_to_grpc_status(grpc_http2_error_code error,
     case GRPC_HTTP2_CANCEL:
       /* http2 cancel translates to STATUS_CANCELLED iff deadline hasn't been
        * exceeded */
-      return gpr_time_cmp(gpr_now(deadline.clock_type), deadline) >= 0
+      return grpc_exec_ctx_now(exec_ctx) > deadline
                  ? GRPC_STATUS_DEADLINE_EXCEEDED
                  : GRPC_STATUS_CANCELLED;
     case GRPC_HTTP2_ENHANCE_YOUR_CALM:
diff --git a/src/core/lib/transport/status_conversion.h b/src/core/lib/transport/status_conversion.h
index e93f3dfd9b..fd58a82cb7 100644
--- a/src/core/lib/transport/status_conversion.h
+++ b/src/core/lib/transport/status_conversion.h
@@ -20,15 +20,25 @@
 #define GRPC_CORE_LIB_TRANSPORT_STATUS_CONVERSION_H
 
 #include <grpc/grpc.h>
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/transport/http2_errors.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Conversion of grpc status codes to http2 error codes (for RST_STREAM) */
 grpc_http2_error_code grpc_status_to_http2_error(grpc_status_code status);
-grpc_status_code grpc_http2_error_to_grpc_status(grpc_http2_error_code error,
-                                                 gpr_timespec deadline);
+grpc_status_code grpc_http2_error_to_grpc_status(grpc_exec_ctx *exec_ctx,
+                                                 grpc_http2_error_code error,
+                                                 grpc_millis deadline);
 
 /* Conversion of HTTP status codes (:status) to grpc status codes */
 grpc_status_code grpc_http2_status_to_grpc_status(int status);
 int grpc_status_to_http2_status(grpc_status_code status);
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_STATUS_CONVERSION_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_STATUS_CONVERSION_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/timeout_encoding.c b/src/core/lib/transport/timeout_encoding.cc
index 02f179d6a3..23a9ef308f 100644
--- a/src/core/lib/transport/timeout_encoding.c
+++ b/src/core/lib/transport/timeout_encoding.cc
@@ -59,60 +59,27 @@ static void enc_seconds(char *buffer, int64_t sec) {
   }
 }
 
-static void enc_nanos(char *buffer, int64_t x) {
+static void enc_millis(char *buffer, int64_t x) {
   x = round_up_to_three_sig_figs(x);
-  if (x < 100000) {
-    if (x % 1000 == 0) {
-      enc_ext(buffer, x / 1000, 'u');
-    } else {
-      enc_ext(buffer, x, 'n');
-    }
-  } else if (x < 100000000) {
-    if (x % 1000000 == 0) {
-      enc_ext(buffer, x / 1000000, 'm');
-    } else {
-      enc_ext(buffer, x / 1000, 'u');
-    }
-  } else if (x < 1000000000) {
-    enc_ext(buffer, x / 1000000, 'm');
+  if (x < GPR_MS_PER_SEC) {
+    enc_ext(buffer, x, 'm');
   } else {
-    /* note that this is only ever called with times of less than one second,
-       so if we reach here the time must have been rounded up to a whole second
-       (and no more) */
-    memcpy(buffer, "1S", 3);
-  }
-}
-
-static void enc_micros(char *buffer, int64_t x) {
-  x = round_up_to_three_sig_figs(x);
-  if (x < 100000) {
-    if (x % 1000 == 0) {
-      enc_ext(buffer, x / 1000, 'm');
+    if (x % GPR_MS_PER_SEC == 0) {
+      enc_seconds(buffer, x / GPR_MS_PER_SEC);
     } else {
-      enc_ext(buffer, x, 'u');
+      enc_ext(buffer, x, 'm');
     }
-  } else if (x < 100000000) {
-    if (x % 1000000 == 0) {
-      enc_ext(buffer, x / 1000000, 'S');
-    } else {
-      enc_ext(buffer, x / 1000, 'm');
-    }
-  } else {
-    enc_ext(buffer, x / 1000000, 'S');
   }
 }
 
-void grpc_http2_encode_timeout(gpr_timespec timeout, char *buffer) {
-  if (timeout.tv_sec < 0) {
+void grpc_http2_encode_timeout(grpc_millis timeout, char *buffer) {
+  if (timeout <= 0) {
     enc_tiny(buffer);
-  } else if (timeout.tv_sec == 0) {
-    enc_nanos(buffer, timeout.tv_nsec);
-  } else if (timeout.tv_sec < 1000 && timeout.tv_nsec != 0) {
-    enc_micros(buffer,
-               (int64_t)(timeout.tv_sec * 1000000) +
-                   (timeout.tv_nsec / 1000 + (timeout.tv_nsec % 1000 != 0)));
+  } else if (timeout < 1000 * GPR_MS_PER_SEC) {
+    enc_millis(buffer, timeout);
   } else {
-    enc_seconds(buffer, timeout.tv_sec + (timeout.tv_nsec != 0));
+    enc_seconds(buffer,
+                timeout / GPR_MS_PER_SEC + (timeout % GPR_MS_PER_SEC != 0));
   }
 }
 
@@ -121,8 +88,8 @@ static int is_all_whitespace(const char *p, const char *end) {
   return p == end;
 }
 
-int grpc_http2_decode_timeout(grpc_slice text, gpr_timespec *timeout) {
-  int32_t x = 0;
+int grpc_http2_decode_timeout(grpc_slice text, grpc_millis *timeout) {
+  grpc_millis x = 0;
   const uint8_t *p = GRPC_SLICE_START_PTR(text);
   const uint8_t *end = GRPC_SLICE_END_PTR(text);
   int have_digit = 0;
@@ -136,7 +103,7 @@ int grpc_http2_decode_timeout(grpc_slice text, gpr_timespec *timeout) {
     /* spec allows max. 8 digits, but we allow values up to 1,000,000,000 */
     if (x >= (100 * 1000 * 1000)) {
       if (x != (100 * 1000 * 1000) || digit != 0) {
-        *timeout = gpr_inf_future(GPR_TIMESPAN);
+        *timeout = GRPC_MILLIS_INF_FUTURE;
         return 1;
       }
     }
@@ -150,22 +117,22 @@ int grpc_http2_decode_timeout(grpc_slice text, gpr_timespec *timeout) {
   /* decode unit specifier */
   switch (*p) {
     case 'n':
-      *timeout = gpr_time_from_nanos(x, GPR_TIMESPAN);
+      *timeout = x / GPR_NS_PER_MS + (x % GPR_NS_PER_MS != 0);
       break;
     case 'u':
-      *timeout = gpr_time_from_micros(x, GPR_TIMESPAN);
+      *timeout = x / GPR_US_PER_MS + (x % GPR_US_PER_MS != 0);
       break;
     case 'm':
-      *timeout = gpr_time_from_millis(x, GPR_TIMESPAN);
+      *timeout = x;
       break;
     case 'S':
-      *timeout = gpr_time_from_seconds(x, GPR_TIMESPAN);
+      *timeout = x * GPR_MS_PER_SEC;
       break;
     case 'M':
-      *timeout = gpr_time_from_minutes(x, GPR_TIMESPAN);
+      *timeout = x * 60 * GPR_MS_PER_SEC;
       break;
     case 'H':
-      *timeout = gpr_time_from_hours(x, GPR_TIMESPAN);
+      *timeout = x * 60 * 60 * GPR_MS_PER_SEC;
       break;
     default:
       return 0;
diff --git a/src/core/lib/transport/timeout_encoding.h b/src/core/lib/transport/timeout_encoding.h
index 7ff35c4083..25cb663959 100644
--- a/src/core/lib/transport/timeout_encoding.h
+++ b/src/core/lib/transport/timeout_encoding.h
@@ -22,13 +22,22 @@
 #include <grpc/slice.h>
 #include <grpc/support/time.h>
 
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/support/string.h"
 
 #define GRPC_HTTP2_TIMEOUT_ENCODE_MIN_BUFSIZE (GPR_LTOA_MIN_BUFSIZE + 1)
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Encode/decode timeouts to the GRPC over HTTP/2 format;
    encoding may round up arbitrarily */
-void grpc_http2_encode_timeout(gpr_timespec timeout, char *buffer);
-int grpc_http2_decode_timeout(grpc_slice text, gpr_timespec *timeout);
+void grpc_http2_encode_timeout(grpc_millis timeout, char *buffer);
+int grpc_http2_decode_timeout(grpc_slice text, grpc_millis *timeout);
+
+#ifdef __cplusplus
+}
+#endif
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_TIMEOUT_ENCODING_H */
+#endif /* GRPC_CORE_LIB_TRANSPORT_TIMEOUT_ENCODING_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.cc
index 682a820b48..ab4f938e7b 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.cc
@@ -110,10 +110,11 @@ grpc_slice grpc_slice_from_stream_owned_buffer(grpc_stream_refcount *refcount,
 }
 
 static const grpc_slice_refcount_vtable stream_ref_slice_vtable = {
-    .ref = slice_stream_ref,
-    .unref = slice_stream_unref,
-    .eq = grpc_slice_default_eq_impl,
-    .hash = grpc_slice_default_hash_impl};
+    slice_stream_ref,            /* ref */
+    slice_stream_unref,          /* unref */
+    grpc_slice_default_eq_impl,  /* eq */
+    grpc_slice_default_hash_impl /* hash */
+};
 
 #ifndef NDEBUG
 void grpc_stream_ref_init(grpc_stream_refcount *refcount, int initial_refs,
diff --git a/src/core/lib/transport/transport_impl.h b/src/core/lib/transport/transport_impl.h
index bbae69c223..41d34d3954 100644
--- a/src/core/lib/transport/transport_impl.h
+++ b/src/core/lib/transport/transport_impl.h
@@ -21,6 +21,10 @@
 
 #include "src/core/lib/transport/transport.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct grpc_transport_vtable {
   /* Memory required for a single stream element - this is allocated by upper
      layers and initialized by the transport */
@@ -69,4 +73,8 @@ struct grpc_transport {
   const grpc_transport_vtable *vtable;
 };
 
-#endif /* GRPC_CORE_LIB_TRANSPORT_TRANSPORT_IMPL_H */
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_TRANSPORT_IMPL_H */
\ No newline at end of file
diff --git a/src/core/lib/transport/transport_op_string.c b/src/core/lib/transport/transport_op_string.cc
index 858664715c..cc11b0cc49 100644
--- a/src/core/lib/transport/transport_op_string.c
+++ b/src/core/lib/transport/transport_op_string.cc
@@ -16,8 +16,11 @@
  *
  */
 
+#include <grpc/support/port_platform.h>
+
 #include "src/core/lib/channel/channel_stack.h"
 
+#include <inttypes.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
@@ -48,10 +51,9 @@ static void put_metadata_list(gpr_strvec *b, grpc_metadata_batch md) {
     if (m != md.list.head) gpr_strvec_add(b, gpr_strdup(", "));
     put_metadata(b, m->md);
   }
-  if (gpr_time_cmp(md.deadline, gpr_inf_future(md.deadline.clock_type)) != 0) {
+  if (md.deadline != GRPC_MILLIS_INF_FUTURE) {
     char *tmp;
-    gpr_asprintf(&tmp, " deadline=%" PRId64 ".%09d", md.deadline.tv_sec,
-                 md.deadline.tv_nsec);
+    gpr_asprintf(&tmp, " deadline=%" PRIdPTR, md.deadline);
     gpr_strvec_add(b, tmp);
   }
 }