Merge remote-tracking branch 'upstream/master' into get_tos

11 files changed, 304 insertions, 164 deletions

diff --git a/src/core/ext/transport/chttp2/alpn/alpn.c b/src/core/ext/transport/chttp2/alpn/alpn.c
index 48b0217265..55710dc5ae 100644
--- a/src/core/ext/transport/chttp2/alpn/alpn.c
+++ b/src/core/ext/transport/chttp2/alpn/alpn.c
@@ -36,7 +36,7 @@
 #include <grpc/support/useful.h>
 
 /* in order of preference */
-static const char *const supported_versions[] = {"h2"};
+static const char *const supported_versions[] = {"grpc-exp", "h2"};
 
 int grpc_chttp2_is_alpn_version_supported(const char *version, size_t size) {
   size_t i;
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create.c b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
index c2b59569fd..71a06e118b 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
@@ -40,9 +40,9 @@
 #include <grpc/support/slice.h>
 #include <grpc/support/slice_buffer.h>
 
-#include "src/core/ext/client_config/client_channel.h"
-#include "src/core/ext/client_config/http_connect_handshaker.h"
-#include "src/core/ext/client_config/resolver_registry.h"
+#include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/http_connect_handshaker.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/compress_filter.h"
@@ -52,6 +52,10 @@
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/channel.h"
 
+//
+// connector
+//
+
 typedef struct {
   grpc_connector base;
   gpr_refcount refs;
@@ -150,42 +154,27 @@ static void connector_connect(grpc_exec_ctx *exec_ctx, grpc_connector *con,
   c->tcp = NULL;
   grpc_closure_init(&c->connected, connected, c);
   grpc_tcp_client_connect(exec_ctx, &c->connected, &c->tcp,
-                          args->interested_parties, args->addr, args->addr_len,
-                          args->deadline);
+                          args->interested_parties, args->channel_args,
+                          args->addr, args->deadline);
 }
 
 static const grpc_connector_vtable connector_vtable = {
     connector_ref, connector_unref, connector_shutdown, connector_connect};
 
-typedef struct {
-  grpc_client_channel_factory base;
-  gpr_refcount refs;
-  grpc_channel_args *merge_args;
-} client_channel_factory;
+//
+// client_channel_factory
+//
 
 static void client_channel_factory_ref(
-    grpc_client_channel_factory *cc_factory) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  gpr_ref(&f->refs);
-}
+    grpc_client_channel_factory *cc_factory) {}
 
 static void client_channel_factory_unref(
-    grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  if (gpr_unref(&f->refs)) {
-    grpc_channel_args_destroy(f->merge_args);
-    gpr_free(f);
-  }
-}
+    grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory) {}
 
 static grpc_subchannel *client_channel_factory_create_subchannel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
-    grpc_subchannel_args *args) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
+    const grpc_subchannel_args *args) {
   connector *c = gpr_malloc(sizeof(*c));
-  grpc_channel_args *final_args =
-      grpc_channel_args_merge(args->args, f->merge_args);
-  grpc_subchannel *s;
   memset(c, 0, sizeof(*c));
   c->base.vtable = &connector_vtable;
   gpr_ref_init(&c->refs, 1);
@@ -197,23 +186,18 @@ static grpc_subchannel *client_channel_factory_create_subchannel(
         grpc_http_connect_handshaker_create(proxy_name, args->server_name));
     gpr_free(proxy_name);
   }
-  args->args = final_args;
-  s = grpc_subchannel_create(exec_ctx, &c->base, args);
+  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, &c->base, args);
   grpc_connector_unref(exec_ctx, &c->base);
-  grpc_channel_args_destroy(final_args);
   return s;
 }
 
 static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
-    grpc_channel_args *args) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  grpc_channel_args *final_args = grpc_channel_args_merge(args, f->merge_args);
-  grpc_channel *channel = grpc_channel_create(exec_ctx, target, final_args,
-                                              GRPC_CLIENT_CHANNEL, NULL);
-  grpc_channel_args_destroy(final_args);
-  grpc_resolver *resolver = grpc_resolver_create(target);
+    const grpc_channel_args *args) {
+  grpc_channel *channel =
+      grpc_channel_create(exec_ctx, target, args, GRPC_CLIENT_CHANNEL, NULL);
+  grpc_resolver *resolver = grpc_resolver_create(target, args);
   if (!resolver) {
     GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, channel,
                                 "client_channel_factory_create_channel");
@@ -221,7 +205,7 @@ static grpc_channel *client_channel_factory_create_channel(
   }
 
   grpc_client_channel_finish_initialization(
-      exec_ctx, grpc_channel_get_channel_stack(channel), resolver, &f->base);
+      exec_ctx, grpc_channel_get_channel_stack(channel), resolver, cc_factory);
   GRPC_RESOLVER_UNREF(exec_ctx, resolver, "create_channel");
 
   return channel;
@@ -232,6 +216,9 @@ static const grpc_client_channel_factory_vtable client_channel_factory_vtable =
      client_channel_factory_create_subchannel,
      client_channel_factory_create_channel};
 
+static grpc_client_channel_factory client_channel_factory = {
+    &client_channel_factory_vtable};
+
 /* Create a client channel:
    Asynchronously: - resolve target
                    - connect to it (trying alternatives as presented)
@@ -245,16 +232,12 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
       (target, args, reserved));
   GPR_ASSERT(!reserved);
 
-  client_channel_factory *f = gpr_malloc(sizeof(*f));
-  memset(f, 0, sizeof(*f));
-  f->base.vtable = &client_channel_factory_vtable;
-  gpr_ref_init(&f->refs, 1);
-  f->merge_args = grpc_channel_args_copy(args);
-
+  grpc_client_channel_factory *factory =
+      (grpc_client_channel_factory *)&client_channel_factory;
   grpc_channel *channel = client_channel_factory_create_channel(
-      &exec_ctx, &f->base, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, NULL);
+      &exec_ctx, factory, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, args);
 
-  grpc_client_channel_factory_unref(&exec_ctx, &f->base);
+  grpc_client_channel_factory_unref(&exec_ctx, factory);
   grpc_exec_ctx_finish(&exec_ctx);
 
   return channel != NULL ? channel : grpc_lame_client_channel_create(
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
index b2c5e5b088..1e5b1c22e3 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
@@ -44,6 +44,7 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/tcp_client_posix.h"
 #include "src/core/lib/iomgr/tcp_posix.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/channel.h"
@@ -65,9 +66,8 @@ grpc_channel *grpc_insecure_channel_create_from_fd(
   int flags = fcntl(fd, F_GETFL, 0);
   GPR_ASSERT(fcntl(fd, F_SETFL, flags | O_NONBLOCK) == 0);
 
-  grpc_endpoint *client =
-      grpc_tcp_create(grpc_fd_create(fd, "client"),
-                      GRPC_TCP_DEFAULT_READ_SLICE_SIZE, "fd-client");
+  grpc_endpoint *client = grpc_tcp_client_create_from_fd(
+      &exec_ctx, grpc_fd_create(fd, "client"), args, "fd-client");
 
   grpc_transport *transport =
       grpc_create_chttp2_transport(&exec_ctx, final_args, client, 1);
diff --git a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
index 31c54ff74c..d0ac72a011 100644
--- a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
+++ b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
@@ -40,9 +40,9 @@
 #include <grpc/support/slice.h>
 #include <grpc/support/slice_buffer.h>
 
-#include "src/core/ext/client_config/client_channel.h"
-#include "src/core/ext/client_config/http_connect_handshaker.h"
-#include "src/core/ext/client_config/resolver_registry.h"
+#include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/http_connect_handshaker.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker.h"
@@ -54,6 +54,10 @@
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/tsi/transport_security_interface.h"
 
+//
+// connector
+//
+
 typedef struct {
   grpc_connector base;
   gpr_refcount refs;
@@ -210,16 +214,19 @@ static void connector_connect(grpc_exec_ctx *exec_ctx, grpc_connector *con,
   grpc_closure_init(&c->connected_closure, connected, c);
   grpc_tcp_client_connect(
       exec_ctx, &c->connected_closure, &c->newly_connecting_endpoint,
-      args->interested_parties, args->addr, args->addr_len, args->deadline);
+      args->interested_parties, args->channel_args, args->addr, args->deadline);
 }
 
 static const grpc_connector_vtable connector_vtable = {
     connector_ref, connector_unref, connector_shutdown, connector_connect};
 
+//
+// client_channel_factory
+//
+
 typedef struct {
   grpc_client_channel_factory base;
   gpr_refcount refs;
-  grpc_channel_args *merge_args;
   grpc_channel_security_connector *security_connector;
 } client_channel_factory;
 
@@ -235,19 +242,15 @@ static void client_channel_factory_unref(
   if (gpr_unref(&f->refs)) {
     GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
                                   "client_channel_factory");
-    grpc_channel_args_destroy(f->merge_args);
     gpr_free(f);
   }
 }
 
 static grpc_subchannel *client_channel_factory_create_subchannel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
-    grpc_subchannel_args *args) {
+    const grpc_subchannel_args *args) {
   client_channel_factory *f = (client_channel_factory *)cc_factory;
   connector *c = gpr_malloc(sizeof(*c));
-  grpc_channel_args *final_args =
-      grpc_channel_args_merge(args->args, f->merge_args);
-  grpc_subchannel *s;
   memset(c, 0, sizeof(*c));
   c->base.vtable = &connector_vtable;
   c->security_connector = f->security_connector;
@@ -261,25 +264,19 @@ static grpc_subchannel *client_channel_factory_create_subchannel(
   }
   gpr_mu_init(&c->mu);
   gpr_ref_init(&c->refs, 1);
-  args->args = final_args;
-  s = grpc_subchannel_create(exec_ctx, &c->base, args);
+  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, &c->base, args);
   grpc_connector_unref(exec_ctx, &c->base);
-  grpc_channel_args_destroy(final_args);
   return s;
 }
 
 static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
-    grpc_channel_args *args) {
+    const grpc_channel_args *args) {
   client_channel_factory *f = (client_channel_factory *)cc_factory;
-
-  grpc_channel_args *final_args = grpc_channel_args_merge(args, f->merge_args);
-  grpc_channel *channel = grpc_channel_create(exec_ctx, target, final_args,
-                                              GRPC_CLIENT_CHANNEL, NULL);
-  grpc_channel_args_destroy(final_args);
-
-  grpc_resolver *resolver = grpc_resolver_create(target);
+  grpc_channel *channel =
+      grpc_channel_create(exec_ctx, target, args, GRPC_CLIENT_CHANNEL, NULL);
+  grpc_resolver *resolver = grpc_resolver_create(target, args);
   if (resolver != NULL) {
     grpc_client_channel_finish_initialization(
         exec_ctx, grpc_channel_get_channel_stack(channel), resolver, &f->base);
@@ -289,9 +286,6 @@ static grpc_channel *client_channel_factory_create_channel(
                                 "client_channel_factory_create_channel");
     channel = NULL;
   }
-
-  GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
-                                "client_channel_factory_create_channel");
   return channel;
 }
 
@@ -308,19 +302,13 @@ grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
                                          const char *target,
                                          const grpc_channel_args *args,
                                          void *reserved) {
-  grpc_arg connector_arg;
-  grpc_channel_args *args_copy;
-  grpc_channel_args *new_args_from_connector;
-  grpc_channel_security_connector *security_connector;
-  client_channel_factory *f;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-
   GRPC_API_TRACE(
       "grpc_secure_channel_create(creds=%p, target=%s, args=%p, "
       "reserved=%p)",
       4, (creds, target, args, reserved));
   GPR_ASSERT(reserved == NULL);
-
+  // Make sure security connector does not already exist in args.
   if (grpc_find_security_connector_in_args(args) != NULL) {
     gpr_log(GPR_ERROR, "Cannot set security context in channel args.");
     grpc_exec_ctx_finish(&exec_ctx);
@@ -328,7 +316,9 @@ grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
         target, GRPC_STATUS_INTERNAL,
         "Security connector exists in channel args.");
   }
-
+  // Create security connector and construct new channel args.
+  grpc_channel_security_connector *security_connector;
+  grpc_channel_args *new_args_from_connector;
   if (grpc_channel_credentials_create_security_connector(
           creds, target, args, &security_connector, &new_args_from_connector) !=
       GRPC_SECURITY_OK) {
@@ -336,32 +326,30 @@ grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
     return grpc_lame_client_channel_create(
         target, GRPC_STATUS_INTERNAL, "Failed to create security connector.");
   }
-
-  connector_arg = grpc_security_connector_to_arg(&security_connector->base);
-  args_copy = grpc_channel_args_copy_and_add(
+  grpc_arg connector_arg =
+      grpc_security_connector_to_arg(&security_connector->base);
+  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(
       new_args_from_connector != NULL ? new_args_from_connector : args,
       &connector_arg, 1);
-
-  f = gpr_malloc(sizeof(*f));
-  memset(f, 0, sizeof(*f));
-  f->base.vtable = &client_channel_factory_vtable;
-  gpr_ref_init(&f->refs, 1);
-
-  f->merge_args = grpc_channel_args_copy(args_copy);
-  grpc_channel_args_destroy(args_copy);
   if (new_args_from_connector != NULL) {
     grpc_channel_args_destroy(new_args_from_connector);
   }
-
+  // Create client channel factory.
+  client_channel_factory *f = gpr_malloc(sizeof(*f));
+  memset(f, 0, sizeof(*f));
+  f->base.vtable = &client_channel_factory_vtable;
+  gpr_ref_init(&f->refs, 1);
   GRPC_SECURITY_CONNECTOR_REF(&security_connector->base,
                               "grpc_secure_channel_create");
   f->security_connector = security_connector;
-
+  // Create channel.
   grpc_channel *channel = client_channel_factory_create_channel(
-      &exec_ctx, &f->base, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, NULL);
-
+      &exec_ctx, &f->base, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
+  // Clean up.
+  GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
+                                "secure_client_channel_factory_create_channel");
+  grpc_channel_args_destroy(new_args);
   grpc_client_channel_factory_unref(&exec_ctx, &f->base);
   grpc_exec_ctx_finish(&exec_ctx);
-
   return channel; /* may be NULL */
 }
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
index f0e07429fa..d42611b863 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
@@ -139,8 +139,8 @@ int grpc_server_add_insecure_http2_port(grpc_server *server, const char *addr) {
     goto error;
   }
 
-  err =
-      grpc_tcp_server_create(NULL, grpc_server_get_channel_args(server), &tcp);
+  err = grpc_tcp_server_create(&exec_ctx, NULL,
+                               grpc_server_get_channel_args(server), &tcp);
   if (err != GRPC_ERROR_NONE) {
     goto error;
   }
@@ -148,9 +148,7 @@ int grpc_server_add_insecure_http2_port(grpc_server *server, const char *addr) {
   const size_t naddrs = resolved->naddrs;
   errors = gpr_malloc(sizeof(*errors) * naddrs);
   for (i = 0; i < naddrs; i++) {
-    errors[i] = grpc_tcp_server_add_port(
-        tcp, (struct sockaddr *)&resolved->addrs[i].addr,
-        resolved->addrs[i].len, &port_temp);
+    errors[i] = grpc_tcp_server_add_port(tcp, &resolved->addrs[i], &port_temp);
     if (errors[i] == GRPC_ERROR_NONE) {
       if (port_num == -1) {
         port_num = port_temp;
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
index 9af17fb5ae..aa2ecf5743 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
@@ -57,8 +57,12 @@ void grpc_server_add_insecure_channel_from_fd(grpc_server *server,
   char *name;
   gpr_asprintf(&name, "fd:%d", fd);
 
-  grpc_endpoint *server_endpoint = grpc_tcp_create(
-      grpc_fd_create(fd, name), GRPC_TCP_DEFAULT_READ_SLICE_SIZE, name);
+  grpc_resource_quota *resource_quota = grpc_resource_quota_from_channel_args(
+      grpc_server_get_channel_args(server));
+  grpc_endpoint *server_endpoint =
+      grpc_tcp_create(grpc_fd_create(fd, name), resource_quota,
+                      GRPC_TCP_DEFAULT_READ_SLICE_SIZE, name);
+  grpc_resource_quota_internal_unref(&exec_ctx, resource_quota);
 
   gpr_free(name);
 
diff --git a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
index 563271f4f8..7ad687042d 100644
--- a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
@@ -271,7 +271,8 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr,
   memset(server_state, 0, sizeof(*server_state));
   grpc_closure_init(&server_state->tcp_server_shutdown_complete,
                     tcp_server_shutdown_complete, server_state);
-  err = grpc_tcp_server_create(&server_state->tcp_server_shutdown_complete,
+  err = grpc_tcp_server_create(&exec_ctx,
+                               &server_state->tcp_server_shutdown_complete,
                                grpc_server_get_channel_args(server), &tcp);
   if (err != GRPC_ERROR_NONE) {
     goto error;
@@ -286,9 +287,7 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr,
 
   errors = gpr_malloc(sizeof(*errors) * resolved->naddrs);
   for (i = 0; i < resolved->naddrs; i++) {
-    errors[i] = grpc_tcp_server_add_port(
-        tcp, (struct sockaddr *)&resolved->addrs[i].addr,
-        resolved->addrs[i].len, &port_temp);
+    errors[i] = grpc_tcp_server_add_port(tcp, &resolved->addrs[i], &port_temp);
     if (errors[i] == GRPC_ERROR_NONE) {
       if (port_num == -1) {
         port_num = port_temp;
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 9f7bc818b6..b61a3a0314 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -114,6 +114,20 @@ static void fail_pending_writes(grpc_exec_ctx *exec_ctx,
                                 grpc_chttp2_transport *t, grpc_chttp2_stream *s,
                                 grpc_error *error);
 
+static void benign_reclaimer(grpc_exec_ctx *exec_ctx, void *t,
+                             grpc_error *error);
+static void benign_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *t,
+                                    grpc_error *error);
+static void destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *t,
+                                  grpc_error *error);
+static void destructive_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *t,
+                                         grpc_error *error);
+
+static void post_benign_reclaimer(grpc_exec_ctx *exec_ctx,
+                                  grpc_chttp2_transport *t);
+static void post_destructive_reclaimer(grpc_exec_ctx *exec_ctx,
+                                       grpc_chttp2_transport *t);
+
 static void close_transport_locked(grpc_exec_ctx *exec_ctx,
                                    grpc_chttp2_transport *t, grpc_error *error);
 static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -241,6 +255,11 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_closure_init(&t->write_action_end_locked, write_action_end_locked, t);
   grpc_closure_init(&t->read_action_begin, read_action_begin, t);
   grpc_closure_init(&t->read_action_locked, read_action_locked, t);
+  grpc_closure_init(&t->benign_reclaimer, benign_reclaimer, t);
+  grpc_closure_init(&t->destructive_reclaimer, destructive_reclaimer, t);
+  grpc_closure_init(&t->benign_reclaimer_locked, benign_reclaimer_locked, t);
+  grpc_closure_init(&t->destructive_reclaimer_locked,
+                    destructive_reclaimer_locked, t);
 
   grpc_chttp2_goaway_parser_init(&t->goaway_parser);
   grpc_chttp2_hpack_parser_init(&t->hpack_parser);
@@ -362,6 +381,7 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
 
   grpc_chttp2_initiate_write(exec_ctx, t, false, "init");
+  post_benign_reclaimer(exec_ctx, t);
 }
 
 static void destroy_transport_locked(grpc_exec_ctx *exec_ctx, void *tp,
@@ -467,6 +487,7 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     *t->accepting_stream = s;
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
+    post_destructive_reclaimer(exec_ctx, t);
   }
 
   GPR_TIMER_END("init_stream", 0);
@@ -675,6 +696,13 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
     close_transport_locked(exec_ctx, t, GRPC_ERROR_REF(error));
   }
 
+  if (t->sent_goaway_state == GRPC_CHTTP2_GOAWAY_SEND_SCHEDULED) {
+    t->sent_goaway_state = GRPC_CHTTP2_GOAWAY_SENT;
+    if (grpc_chttp2_stream_map_size(&t->stream_map) == 0) {
+      close_transport_locked(exec_ctx, t, GRPC_ERROR_CREATE("goaway sent"));
+    }
+  }
+
   grpc_chttp2_end_write(exec_ctx, t, GRPC_ERROR_REF(error));
 
   switch (t->write_state) {
@@ -780,6 +808,7 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     s->max_recv_bytes = GPR_MAX(stream_incoming_window, s->max_recv_bytes);
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
+    post_destructive_reclaimer(exec_ctx, t);
     grpc_chttp2_become_writable(exec_ctx, t, s, true, "new_stream");
   }
   /* cancel out streams that will never be started */
@@ -853,61 +882,60 @@ static bool contains_non_ok_status(grpc_metadata_batch *batch) {
 
 static void add_fetched_slice_locked(grpc_exec_ctx *exec_ctx,
                                      grpc_chttp2_transport *t,
-                                     grpc_chttp2_stream *s);
+                                     grpc_chttp2_stream *s) {
+  s->fetched_send_message_length +=
+      (uint32_t)GPR_SLICE_LENGTH(s->fetching_slice);
+  gpr_slice_buffer_add(&s->flow_controlled_buffer, s->fetching_slice);
+  if (s->id != 0) {
+    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
+  }
+}
 
 static void continue_fetching_send_locked(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_transport *t,
                                           grpc_chttp2_stream *s) {
-  if (s->fetching_send_message == NULL) {
-    /* Stream was cancelled before message fetch completed */
-    abort(); /* TODO(ctiller): what cleanup here? */
-    return;
-  }
-  if (s->fetched_send_message_length == s->fetching_send_message->length) {
-    int64_t notify_offset = s->next_message_end_offset;
-    if (notify_offset <= s->flow_controlled_bytes_written) {
-      grpc_chttp2_complete_closure_step(
-          exec_ctx, t, s, &s->fetching_send_message_finished, GRPC_ERROR_NONE,
-          "fetching_send_message_finished");
-    } else {
-      grpc_chttp2_write_cb *cb = t->write_cb_pool;
-      if (cb == NULL) {
-        cb = gpr_malloc(sizeof(*cb));
+  for (;;) {
+    if (s->fetching_send_message == NULL) {
+      /* Stream was cancelled before message fetch completed */
+      abort(); /* TODO(ctiller): what cleanup here? */
+      return;  /* early out */
+    }
+    if (s->fetched_send_message_length == s->fetching_send_message->length) {
+      int64_t notify_offset = s->next_message_end_offset;
+      if (notify_offset <= s->flow_controlled_bytes_written) {
+        grpc_chttp2_complete_closure_step(
+            exec_ctx, t, s, &s->fetching_send_message_finished, GRPC_ERROR_NONE,
+            "fetching_send_message_finished");
       } else {
-        t->write_cb_pool = cb->next;
+        grpc_chttp2_write_cb *cb = t->write_cb_pool;
+        if (cb == NULL) {
+          cb = gpr_malloc(sizeof(*cb));
+        } else {
+          t->write_cb_pool = cb->next;
+        }
+        cb->call_at_byte = notify_offset;
+        cb->closure = s->fetching_send_message_finished;
+        s->fetching_send_message_finished = NULL;
+        cb->next = s->on_write_finished_cbs;
+        s->on_write_finished_cbs = cb;
       }
-      cb->call_at_byte = notify_offset;
-      cb->closure = s->fetching_send_message_finished;
-      s->fetching_send_message_finished = NULL;
-      cb->next = s->on_write_finished_cbs;
-      s->on_write_finished_cbs = cb;
+      s->fetching_send_message = NULL;
+      return; /* early out */
+    } else if (grpc_byte_stream_next(exec_ctx, s->fetching_send_message,
+                                     &s->fetching_slice, UINT32_MAX,
+                                     &s->complete_fetch)) {
+      add_fetched_slice_locked(exec_ctx, t, s);
     }
-    s->fetching_send_message = NULL;
-  } else if (grpc_byte_stream_next(exec_ctx, s->fetching_send_message,
-                                   &s->fetching_slice, UINT32_MAX,
-                                   &s->complete_fetch)) {
-    add_fetched_slice_locked(exec_ctx, t, s);
   }
 }
 
-static void add_fetched_slice_locked(grpc_exec_ctx *exec_ctx,
-                                     grpc_chttp2_transport *t,
-                                     grpc_chttp2_stream *s) {
-  s->fetched_send_message_length +=
-      (uint32_t)GPR_SLICE_LENGTH(s->fetching_slice);
-  gpr_slice_buffer_add(&s->flow_controlled_buffer, s->fetching_slice);
-  if (s->id != 0) {
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
-  }
-  continue_fetching_send_locked(exec_ctx, t, s);
-}
-
 static void complete_fetch_locked(grpc_exec_ctx *exec_ctx, void *gs,
                                   grpc_error *error) {
   grpc_chttp2_stream *s = gs;
   grpc_chttp2_transport *t = s->t;
   if (error == GRPC_ERROR_NONE) {
     add_fetched_slice_locked(exec_ctx, t, s);
+    continue_fetching_send_locked(exec_ctx, t, s);
   } else {
     /* TODO(ctiller): what to do here */
     abort();
@@ -994,9 +1022,14 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       }
       if (!s->write_closed) {
         if (t->is_client) {
-          GPR_ASSERT(s->id == 0);
-          grpc_chttp2_list_add_waiting_for_concurrency(t, s);
-          maybe_start_some_streams(exec_ctx, t);
+          if (!t->closed) {
+            GPR_ASSERT(s->id == 0);
+            grpc_chttp2_list_add_waiting_for_concurrency(t, s);
+            maybe_start_some_streams(exec_ctx, t);
+          } else {
+            grpc_chttp2_cancel_stream(exec_ctx, t, s,
+                                      GRPC_ERROR_CREATE("Transport closed"));
+          }
         } else {
           GPR_ASSERT(s->id != 0);
           grpc_chttp2_become_writable(exec_ctx, t, s, true,
@@ -1186,6 +1219,14 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   gpr_free(msg);
 }
 
+static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                        grpc_chttp2_error_code error, gpr_slice data) {
+  t->sent_goaway_state = GRPC_CHTTP2_GOAWAY_SEND_SCHEDULED;
+  grpc_chttp2_goaway_append(t->last_new_stream_id, (uint32_t)error, data,
+                            &t->qbuf);
+  grpc_chttp2_initiate_write(exec_ctx, t, false, "goaway_sent");
+}
+
 static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
                                         void *stream_op,
                                         grpc_error *error_ignored) {
@@ -1200,15 +1241,9 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
   }
 
   if (op->send_goaway) {
-    t->sent_goaway = 1;
-    grpc_chttp2_goaway_append(
-        t->last_new_stream_id,
-        (uint32_t)grpc_chttp2_grpc_status_to_http2_error(op->goaway_status),
-        gpr_slice_ref(*op->goaway_message), &t->qbuf);
-    close_transport = grpc_chttp2_stream_map_size(&t->stream_map) == 0
-                          ? GRPC_ERROR_CREATE("GOAWAY sent")
-                          : GRPC_ERROR_NONE;
-    grpc_chttp2_initiate_write(exec_ctx, t, false, "goaway_sent");
+    send_goaway(exec_ctx, t,
+                grpc_chttp2_grpc_status_to_http2_error(op->goaway_status),
+                gpr_slice_ref(*op->goaway_message));
   }
 
   if (op->set_accept_stream) {
@@ -1342,10 +1377,14 @@ static void remove_stream(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     s->data_parser.parsing_frame = NULL;
   }
 
-  if (grpc_chttp2_stream_map_size(&t->stream_map) == 0 && t->sent_goaway) {
-    close_transport_locked(
-        exec_ctx, t, GRPC_ERROR_CREATE_REFERENCING(
-                         "Last stream closed after sending GOAWAY", &error, 1));
+  if (grpc_chttp2_stream_map_size(&t->stream_map) == 0) {
+    post_benign_reclaimer(exec_ctx, t);
+    if (t->sent_goaway_state == GRPC_CHTTP2_GOAWAY_SENT) {
+      close_transport_locked(
+          exec_ctx, t,
+          GRPC_ERROR_CREATE_REFERENCING(
+              "Last stream closed after sending GOAWAY", &error, 1));
+    }
   }
   if (grpc_chttp2_list_remove_writable_stream(t, s)) {
     GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2_writing:remove_stream");
@@ -2073,6 +2112,103 @@ grpc_chttp2_incoming_byte_stream *grpc_chttp2_incoming_byte_stream_create(
 }
 
 /*******************************************************************************
+ * RESOURCE QUOTAS
+ */
+
+static void post_benign_reclaimer(grpc_exec_ctx *exec_ctx,
+                                  grpc_chttp2_transport *t) {
+  if (!t->benign_reclaimer_registered) {
+    t->benign_reclaimer_registered = true;
+    GRPC_CHTTP2_REF_TRANSPORT(t, "benign_reclaimer");
+    grpc_resource_user_post_reclaimer(exec_ctx,
+                                      grpc_endpoint_get_resource_user(t->ep),
+                                      false, &t->benign_reclaimer);
+  }
+}
+
+static void post_destructive_reclaimer(grpc_exec_ctx *exec_ctx,
+                                       grpc_chttp2_transport *t) {
+  if (!t->destructive_reclaimer_registered) {
+    t->destructive_reclaimer_registered = true;
+    GRPC_CHTTP2_REF_TRANSPORT(t, "destructive_reclaimer");
+    grpc_resource_user_post_reclaimer(exec_ctx,
+                                      grpc_endpoint_get_resource_user(t->ep),
+                                      true, &t->destructive_reclaimer);
+  }
+}
+
+static void benign_reclaimer(grpc_exec_ctx *exec_ctx, void *arg,
+                             grpc_error *error) {
+  grpc_chttp2_transport *t = arg;
+  grpc_combiner_execute(exec_ctx, t->combiner, &t->benign_reclaimer_locked,
+                        GRPC_ERROR_REF(error), false);
+}
+
+static void destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *arg,
+                                  grpc_error *error) {
+  grpc_chttp2_transport *t = arg;
+  grpc_combiner_execute(exec_ctx, t->combiner, &t->destructive_reclaimer_locked,
+                        GRPC_ERROR_REF(error), false);
+}
+
+static void benign_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                    grpc_error *error) {
+  grpc_chttp2_transport *t = arg;
+  if (error == GRPC_ERROR_NONE &&
+      grpc_chttp2_stream_map_size(&t->stream_map) == 0) {
+    /* Channel with no active streams: send a goaway to try and make it
+     * disconnect cleanly */
+    if (grpc_resource_quota_trace) {
+      gpr_log(GPR_DEBUG, "HTTP2: %s - send goaway to free memory",
+              t->peer_string);
+    }
+    send_goaway(exec_ctx, t, GRPC_CHTTP2_ENHANCE_YOUR_CALM,
+                gpr_slice_from_static_string("Buffers full"));
+  } else if (error == GRPC_ERROR_NONE && grpc_resource_quota_trace) {
+    gpr_log(GPR_DEBUG,
+            "HTTP2: %s - skip benign reclamation, there are still %" PRIdPTR
+            " streams",
+            t->peer_string, grpc_chttp2_stream_map_size(&t->stream_map));
+  }
+  t->benign_reclaimer_registered = false;
+  if (error != GRPC_ERROR_CANCELLED) {
+    grpc_resource_user_finish_reclamation(
+        exec_ctx, grpc_endpoint_get_resource_user(t->ep));
+  }
+  GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "benign_reclaimer");
+}
+
+static void destructive_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                         grpc_error *error) {
+  grpc_chttp2_transport *t = arg;
+  size_t n = grpc_chttp2_stream_map_size(&t->stream_map);
+  t->destructive_reclaimer_registered = false;
+  if (error == GRPC_ERROR_NONE && n > 0) {
+    grpc_chttp2_stream *s = grpc_chttp2_stream_map_rand(&t->stream_map);
+    if (grpc_resource_quota_trace) {
+      gpr_log(GPR_DEBUG, "HTTP2: %s - abandon stream id %d", t->peer_string,
+              s->id);
+    }
+    grpc_chttp2_cancel_stream(
+        exec_ctx, t, s, grpc_error_set_int(GRPC_ERROR_CREATE("Buffers full"),
+                                           GRPC_ERROR_INT_HTTP2_ERROR,
+                                           GRPC_CHTTP2_ENHANCE_YOUR_CALM));
+    if (n > 1) {
+      /* Since we cancel one stream per destructive reclamation, if
+         there are more streams left, we can immediately post a new
+         reclaimer in case the resource quota needs to free more
+         memory */
+      post_destructive_reclaimer(exec_ctx, t);
+    }
+  }
+  if (error != GRPC_ERROR_CANCELLED) {
+    grpc_resource_user_finish_reclamation(
+        exec_ctx, grpc_endpoint_get_resource_user(t->ep));
+  }
+  GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "destructive_reclaimer");
+}
+
+/*******************************************************************************
  * TRACING
  */
 
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index 01f521c360..e0c4a1e925 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -138,6 +138,12 @@ typedef enum {
   GRPC_NUM_SETTING_SETS
 } grpc_chttp2_setting_set;
 
+typedef enum {
+  GRPC_CHTTP2_NO_GOAWAY_SEND,
+  GRPC_CHTTP2_GOAWAY_SEND_SCHEDULED,
+  GRPC_CHTTP2_GOAWAY_SENT,
+} grpc_chttp2_sent_goaway_state;
+
 /* Outstanding ping request data */
 typedef struct grpc_chttp2_outstanding_ping {
   uint8_t id[8];
@@ -249,7 +255,7 @@ struct grpc_chttp2_transport {
   /** have we seen a goaway */
   uint8_t seen_goaway;
   /** have we sent a goaway */
-  uint8_t sent_goaway;
+  grpc_chttp2_sent_goaway_state sent_goaway_state;
 
   /** are the local settings dirty and need to be sent? */
   uint8_t dirtied_local_settings;
@@ -320,6 +326,18 @@ struct grpc_chttp2_transport {
   /* if non-NULL, close the transport with this error when writes are finished
    */
   grpc_error *close_transport_on_writes_finished;
+
+  /* buffer pool state */
+  /** have we scheduled a benign cleanup? */
+  bool benign_reclaimer_registered;
+  /** have we scheduled a destructive cleanup? */
+  bool destructive_reclaimer_registered;
+  /** benign cleanup closure */
+  grpc_closure benign_reclaimer;
+  grpc_closure benign_reclaimer_locked;
+  /** destructive cleanup closure */
+  grpc_closure destructive_reclaimer;
+  grpc_closure destructive_reclaimer_locked;
 };
 
 typedef enum {
diff --git a/src/core/ext/transport/chttp2/transport/stream_map.c b/src/core/ext/transport/chttp2/transport/stream_map.c
index 59b3a14e0a..5f5a28446d 100644
--- a/src/core/ext/transport/chttp2/transport/stream_map.c
+++ b/src/core/ext/transport/chttp2/transport/stream_map.c
@@ -151,6 +151,17 @@ size_t grpc_chttp2_stream_map_size(grpc_chttp2_stream_map *map) {
   return map->count - map->free;
 }
 
+void *grpc_chttp2_stream_map_rand(grpc_chttp2_stream_map *map) {
+  if (map->count == map->free) {
+    return NULL;
+  }
+  if (map->free != 0) {
+    map->count = compact(map->keys, map->values, map->count);
+    map->free = 0;
+  }
+  return map->values[((size_t)rand()) % map->count];
+}
+
 void grpc_chttp2_stream_map_for_each(grpc_chttp2_stream_map *map,
                                      void (*f)(void *user_data, uint32_t key,
                                                void *value),
diff --git a/src/core/ext/transport/chttp2/transport/stream_map.h b/src/core/ext/transport/chttp2/transport/stream_map.h
index e76312dd1a..203f640680 100644
--- a/src/core/ext/transport/chttp2/transport/stream_map.h
+++ b/src/core/ext/transport/chttp2/transport/stream_map.h
@@ -68,6 +68,9 @@ void *grpc_chttp2_stream_map_delete(grpc_chttp2_stream_map *map, uint32_t key);
 /* Return an existing key, or NULL if it does not exist */
 void *grpc_chttp2_stream_map_find(grpc_chttp2_stream_map *map, uint32_t key);
 
+/* Return a random entry */
+void *grpc_chttp2_stream_map_rand(grpc_chttp2_stream_map *map);
+
 /* How many (populated) entries are in the stream map? */
 size_t grpc_chttp2_stream_map_size(grpc_chttp2_stream_map *map);