From 3ff1fa6e05726fb40cc60271a8e6a189bf901eb8 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Thu, 14 Sep 2017 11:07:48 -0700
Subject: Collect stats on why writes are initiated

---
 .../transport/chttp2/transport/chttp2_transport.c  | 239 ++++++++++++++++-----
 .../ext/transport/chttp2/transport/frame_ping.c    |   3 +-
 .../chttp2/transport/frame_window_update.c         |  10 +-
 .../ext/transport/chttp2/transport/hpack_parser.c  |   3 +-
 src/core/ext/transport/chttp2/transport/internal.h |  37 +++-
 src/core/ext/transport/chttp2/transport/writing.c  |   5 +-
 6 files changed, 236 insertions(+), 61 deletions(-)

(limited to 'src/core/ext/transport')

diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 930fa805a0..7e392b6d63 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -144,10 +144,11 @@ static void finish_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
 
 static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                          grpc_error *error);
-static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_chttp2_ping_type ping_type,
-                             grpc_closure *on_initiate,
-                             grpc_closure *on_complete);
+static void send_ping_locked(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+    grpc_chttp2_ping_type ping_type, grpc_closure *on_initiate,
+    grpc_closure *on_complete,
+    grpc_chttp2_initiate_write_reason initiate_write_reason);
 static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                        grpc_error *error);
 
@@ -346,7 +347,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   if (is_client) {
     grpc_slice_buffer_add(&t->outbuf, grpc_slice_from_copied_string(
                                           GRPC_CHTTP2_CLIENT_CONNECT_STRING));
-    grpc_chttp2_initiate_write(exec_ctx, t, "initial_write");
   }
 
   /* configure http2 the way we like it */
@@ -578,7 +578,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     t->keepalive_state = GRPC_CHTTP2_KEEPALIVE_STATE_DISABLED;
   }
 
-  grpc_chttp2_initiate_write(exec_ctx, t, "init");
+  grpc_chttp2_initiate_write(exec_ctx, t,
+                             GRPC_CHTTP2_INITIATE_WRITE_INITIAL_WRITE);
   post_benign_reclaimer(exec_ctx, t);
 }
 
@@ -846,13 +847,91 @@ static void set_write_state(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
 }
 
+static void inc_initiate_write_reason(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_initiate_write_reason reason) {
+  switch (reason) {
+    case GRPC_CHTTP2_INITIATE_WRITE_INITIAL_WRITE:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_INITIAL_WRITE(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_START_NEW_STREAM:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_START_NEW_STREAM(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_MESSAGE:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_SEND_MESSAGE(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_INITIAL_METADATA:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_SEND_INITIAL_METADATA(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_TRAILING_METADATA:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_SEND_TRAILING_METADATA(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_RETRY_SEND_PING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_RETRY_SEND_PING(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_CONTINUE_PINGS:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_CONTINUE_PINGS(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_GOAWAY_SENT:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_GOAWAY_SENT(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_RST_STREAM:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_RST_STREAM(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_CLOSE_FROM_API:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_CLOSE_FROM_API(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_STREAM_FLOW_CONTROL:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_STREAM_FLOW_CONTROL(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_TRANSPORT_FLOW_CONTROL(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_SETTINGS:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_SEND_SETTINGS(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_BDP_ESTIMATOR_PING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_BDP_ESTIMATOR_PING(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_SETTING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_FLOW_CONTROL_UNSTALLED_BY_SETTING(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_FLOW_CONTROL_UNSTALLED_BY_UPDATE(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_APPLICATION_PING(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_KEEPALIVE_PING(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_TRANSPORT_FLOW_CONTROL_UNSTALLED(
+          exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_PING_RESPONSE:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_PING_RESPONSE(exec_ctx);
+      break;
+    case GRPC_CHTTP2_INITIATE_WRITE_FORCE_RST_STREAM:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_FORCE_RST_STREAM(exec_ctx);
+      break;
+  }
+}
+
 void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t, const char *reason) {
+                                grpc_chttp2_transport *t,
+                                grpc_chttp2_initiate_write_reason reason) {
   GPR_TIMER_BEGIN("grpc_chttp2_initiate_write", 0);
 
   switch (t->write_state) {
     case GRPC_CHTTP2_WRITE_STATE_IDLE:
-      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING, reason);
+      inc_initiate_write_reason(exec_ctx, reason);
+      set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
+                      grpc_chttp2_initiate_write_reason_string(reason));
       t->is_first_write_in_batch = true;
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
       GRPC_CLOSURE_SCHED(
@@ -864,7 +943,7 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE,
-                      reason);
+                      grpc_chttp2_initiate_write_reason_string(reason));
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE:
       break;
@@ -872,16 +951,12 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("grpc_chttp2_initiate_write", 0);
 }
 
-void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
-                                 grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s,
-                                 bool also_initiate_write, const char *reason) {
+void grpc_chttp2_mark_stream_writable(grpc_exec_ctx *exec_ctx,
+                                      grpc_chttp2_transport *t,
+                                      grpc_chttp2_stream *s) {
   if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s)) {
     GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:become");
   }
-  if (also_initiate_write) {
-    grpc_chttp2_initiate_write(exec_ctx, t, reason);
-  }
 }
 
 static grpc_closure_scheduler *write_scheduler(grpc_chttp2_transport *t,
@@ -1105,7 +1180,9 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
 
     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");
+    grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+    grpc_chttp2_initiate_write(exec_ctx, t,
+                               GRPC_CHTTP2_INITIATE_WRITE_START_NEW_STREAM);
   }
   /* cancel out streams that will never be started */
   while (t->next_stream_id >= MAX_CLIENT_STREAM_ID &&
@@ -1202,7 +1279,9 @@ static void maybe_become_writable_due_to_send_msg(grpc_exec_ctx *exec_ctx,
                                                   grpc_chttp2_stream *s) {
   if (s->id != 0 && (!s->write_buffering ||
                      s->flow_controlled_buffer.length > t->write_buffer_size)) {
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
+    grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+    grpc_chttp2_initiate_write(exec_ctx, t,
+                               GRPC_CHTTP2_INITIATE_WRITE_SEND_MESSAGE);
   }
 }
 
@@ -1404,14 +1483,13 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
           }
         } else {
           GPR_ASSERT(s->id != 0);
-          bool initiate_write = true;
-          if (op->send_message &&
-              (op->payload->send_message.send_message->flags &
-               GRPC_WRITE_BUFFER_HINT)) {
-            initiate_write = false;
+          grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+          if (!(op->send_message &&
+                (op->payload->send_message.send_message->flags &
+                 GRPC_WRITE_BUFFER_HINT))) {
+            grpc_chttp2_initiate_write(
+                exec_ctx, t, GRPC_CHTTP2_INITIATE_WRITE_SEND_INITIAL_METADATA);
           }
-          grpc_chttp2_become_writable(exec_ctx, t, s, initiate_write,
-                                      "op.send_initial_metadata");
         }
       } else {
         s->send_initial_metadata = NULL;
@@ -1519,8 +1597,9 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       } else if (s->id != 0) {
         /* TODO(ctiller): check if there's flow control for any outstanding
            bytes before going writable */
-        grpc_chttp2_become_writable(exec_ctx, t, s, true,
-                                    "op.send_trailing_metadata");
+        grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+        grpc_chttp2_initiate_write(
+            exec_ctx, t, GRPC_CHTTP2_INITIATE_WRITE_SEND_TRAILING_METADATA);
       }
     }
   }
@@ -1632,15 +1711,17 @@ static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   GRPC_ERROR_UNREF(error);
 }
 
-static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_chttp2_ping_type ping_type,
-                             grpc_closure *on_initiate, grpc_closure *on_ack) {
+static void send_ping_locked(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+    grpc_chttp2_ping_type ping_type, grpc_closure *on_initiate,
+    grpc_closure *on_ack,
+    grpc_chttp2_initiate_write_reason initiate_write_reason) {
   grpc_chttp2_ping_queue *pq = &t->ping_queues[ping_type];
   grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_INITIATE], on_initiate,
                            GRPC_ERROR_NONE);
   if (grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_NEXT], on_ack,
                                GRPC_ERROR_NONE)) {
-    grpc_chttp2_initiate_write(exec_ctx, t, "send_ping");
+    grpc_chttp2_initiate_write(exec_ctx, t, initiate_write_reason);
   }
 }
 
@@ -1648,7 +1729,8 @@ static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                        grpc_error *error) {
   grpc_chttp2_transport *t = (grpc_chttp2_transport *)tp;
   t->ping_state.is_delayed_ping_timer_set = false;
-  grpc_chttp2_initiate_write(exec_ctx, t, "retry_send_ping");
+  grpc_chttp2_initiate_write(exec_ctx, t,
+                             GRPC_CHTTP2_INITIATE_WRITE_RETRY_SEND_PING);
 }
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -1663,7 +1745,8 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
   GRPC_CLOSURE_LIST_SCHED(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
   if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
-    grpc_chttp2_initiate_write(exec_ctx, t, "continue_pings");
+    grpc_chttp2_initiate_write(exec_ctx, t,
+                               GRPC_CHTTP2_INITIATE_WRITE_CONTINUE_PINGS);
   }
 }
 
@@ -1676,7 +1759,8 @@ static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                         &slice, &http_error);
   grpc_chttp2_goaway_append(t->last_new_stream_id, (uint32_t)http_error,
                             grpc_slice_ref_internal(slice), &t->qbuf);
-  grpc_chttp2_initiate_write(exec_ctx, t, "goaway_sent");
+  grpc_chttp2_initiate_write(exec_ctx, t,
+                             GRPC_CHTTP2_INITIATE_WRITE_GOAWAY_SENT);
   GRPC_ERROR_UNREF(error);
 }
 
@@ -1723,7 +1807,8 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
 
   if (op->send_ping) {
     send_ping_locked(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE, NULL,
-                     op->send_ping);
+                     op->send_ping,
+                     GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING);
   }
 
   if (op->on_connectivity_state_change != NULL) {
@@ -1968,7 +2053,8 @@ void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
       grpc_slice_buffer_add(
           &t->qbuf, grpc_chttp2_rst_stream_create(s->id, (uint32_t)http_error,
                                                   &s->stats.outgoing));
-      grpc_chttp2_initiate_write(exec_ctx, t, "rst_stream");
+      grpc_chttp2_initiate_write(exec_ctx, t,
+                                 GRPC_CHTTP2_INITIATE_WRITE_RST_STREAM);
     }
   }
   if (due_to_error != GRPC_ERROR_NONE && !s->seen_error) {
@@ -2289,7 +2375,8 @@ static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                                               &s->stats.outgoing));
 
   grpc_chttp2_mark_stream_closed(exec_ctx, t, s, 1, 1, error);
-  grpc_chttp2_initiate_write(exec_ctx, t, "close_from_api");
+  grpc_chttp2_initiate_write(exec_ctx, t,
+                             GRPC_CHTTP2_INITIATE_WRITE_CLOSE_FROM_API);
 }
 
 typedef struct {
@@ -2324,19 +2411,20 @@ void grpc_chttp2_act_on_flowctl_action(grpc_exec_ctx *exec_ctx,
     case GRPC_CHTTP2_FLOWCTL_NO_ACTION_NEEDED:
       break;
     case GRPC_CHTTP2_FLOWCTL_UPDATE_IMMEDIATELY:
-      grpc_chttp2_become_writable(exec_ctx, t, s, true,
-                                  "immediate stream flowctl");
+      grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+      grpc_chttp2_initiate_write(
+          exec_ctx, t, GRPC_CHTTP2_INITIATE_WRITE_STREAM_FLOW_CONTROL);
       break;
     case GRPC_CHTTP2_FLOWCTL_QUEUE_UPDATE:
-      grpc_chttp2_become_writable(exec_ctx, t, s, false,
-                                  "queue stream flowctl");
+      grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
       break;
   }
   switch (action.send_transport_update) {
     case GRPC_CHTTP2_FLOWCTL_NO_ACTION_NEEDED:
       break;
     case GRPC_CHTTP2_FLOWCTL_UPDATE_IMMEDIATELY:
-      grpc_chttp2_initiate_write(exec_ctx, t, "immediate transport flowctl");
+      grpc_chttp2_initiate_write(
+          exec_ctx, t, GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL);
       break;
     // this is the same as no action b/c every time the transport enters the
     // writing path it will maybe do an update
@@ -2354,7 +2442,8 @@ void grpc_chttp2_act_on_flowctl_action(grpc_exec_ctx *exec_ctx,
                            (uint32_t)action.max_frame_size);
     }
     if (action.send_setting_update == GRPC_CHTTP2_FLOWCTL_UPDATE_IMMEDIATELY) {
-      grpc_chttp2_initiate_write(exec_ctx, t, "immediate setting update");
+      grpc_chttp2_initiate_write(exec_ctx, t,
+                                 GRPC_CHTTP2_INITIATE_WRITE_SEND_SETTINGS);
     }
   }
   if (action.need_ping) {
@@ -2362,7 +2451,8 @@ void grpc_chttp2_act_on_flowctl_action(grpc_exec_ctx *exec_ctx,
     grpc_bdp_estimator_schedule_ping(&t->flow_control.bdp_estimator);
     send_ping_locked(exec_ctx, t,
                      GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE,
-                     &t->start_bdp_ping_locked, &t->finish_bdp_ping_locked);
+                     &t->start_bdp_ping_locked, &t->finish_bdp_ping_locked,
+                     GRPC_CHTTP2_INITIATE_WRITE_BDP_ESTIMATOR_PING);
   }
 }
 
@@ -2441,7 +2531,10 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
       if (t->flow_control.initial_window_update > 0) {
         grpc_chttp2_stream *s;
         while (grpc_chttp2_list_pop_stalled_by_stream(t, &s)) {
-          grpc_chttp2_become_writable(exec_ctx, t, s, true, "unstalled");
+          grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+          grpc_chttp2_initiate_write(
+              exec_ctx, t,
+              GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_SETTING);
         }
       }
       t->flow_control.initial_window_update = 0;
@@ -2556,7 +2649,8 @@ static void init_keepalive_ping_locked(grpc_exec_ctx *exec_ctx, void *arg,
       GRPC_CHTTP2_REF_TRANSPORT(t, "keepalive ping end");
       send_ping_locked(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE,
                        &t->start_keepalive_ping_locked,
-                       &t->finish_keepalive_ping_locked);
+                       &t->finish_keepalive_ping_locked,
+                       GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING);
     } else {
       GRPC_CHTTP2_REF_TRANSPORT(t, "init keepalive ping");
       grpc_timer_init(
@@ -2912,8 +3006,7 @@ grpc_chttp2_incoming_byte_stream *grpc_chttp2_incoming_byte_stream_create(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t, grpc_chttp2_stream *s,
     uint32_t frame_size, uint32_t flags) {
   grpc_chttp2_incoming_byte_stream *incoming_byte_stream =
-      (grpc_chttp2_incoming_byte_stream *)gpr_malloc(
-          sizeof(*incoming_byte_stream));
+      gpr_malloc(sizeof(*incoming_byte_stream));
   incoming_byte_stream->base.length = frame_size;
   incoming_byte_stream->remaining_bytes = frame_size;
   incoming_byte_stream->base.flags = flags;
@@ -3017,6 +3110,56 @@ static void destructive_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
 /*******************************************************************************
  * MONITORING
  */
+
+const char *grpc_chttp2_initiate_write_reason_string(
+    grpc_chttp2_initiate_write_reason reason) {
+  switch (reason) {
+    case GRPC_CHTTP2_INITIATE_WRITE_INITIAL_WRITE:
+      return "INITIAL_WRITE";
+    case GRPC_CHTTP2_INITIATE_WRITE_START_NEW_STREAM:
+      return "START_NEW_STREAM";
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_MESSAGE:
+      return "SEND_MESSAGE";
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_INITIAL_METADATA:
+      return "SEND_INITIAL_METADATA";
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_TRAILING_METADATA:
+      return "SEND_TRAILING_METADATA";
+    case GRPC_CHTTP2_INITIATE_WRITE_RETRY_SEND_PING:
+      return "RETRY_SEND_PING";
+    case GRPC_CHTTP2_INITIATE_WRITE_CONTINUE_PINGS:
+      return "CONTINUE_PINGS";
+    case GRPC_CHTTP2_INITIATE_WRITE_GOAWAY_SENT:
+      return "GOAWAY_SENT";
+    case GRPC_CHTTP2_INITIATE_WRITE_RST_STREAM:
+      return "RST_STREAM";
+    case GRPC_CHTTP2_INITIATE_WRITE_CLOSE_FROM_API:
+      return "CLOSE_FROM_API";
+    case GRPC_CHTTP2_INITIATE_WRITE_STREAM_FLOW_CONTROL:
+      return "STREAM_FLOW_CONTROL";
+    case GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL:
+      return "TRANSPORT_FLOW_CONTROL";
+    case GRPC_CHTTP2_INITIATE_WRITE_SEND_SETTINGS:
+      return "SEND_SETTINGS";
+    case GRPC_CHTTP2_INITIATE_WRITE_BDP_ESTIMATOR_PING:
+      return "BDP_ESTIMATOR_PING";
+    case GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_SETTING:
+      return "FLOW_CONTROL_UNSTALLED_BY_SETTING";
+    case GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE:
+      return "FLOW_CONTROL_UNSTALLED_BY_UPDATE";
+    case GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING:
+      return "APPLICATION_PING";
+    case GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING:
+      return "KEEPALIVE_PING";
+    case GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED:
+      return "TRANSPORT_FLOW_CONTROL_UNSTALLED";
+    case GRPC_CHTTP2_INITIATE_WRITE_PING_RESPONSE:
+      return "PING_RESPONSE";
+    case GRPC_CHTTP2_INITIATE_WRITE_FORCE_RST_STREAM:
+      return "FORCE_RST_STREAM";
+  }
+  GPR_UNREACHABLE_CODE(return "unknown");
+}
+
 static grpc_endpoint *chttp2_get_endpoint(grpc_exec_ctx *exec_ctx,
                                           grpc_transport *t) {
   return ((grpc_chttp2_transport *)t)->ep;
diff --git a/src/core/ext/transport/chttp2/transport/frame_ping.c b/src/core/ext/transport/chttp2/transport/frame_ping.c
index 582fd7bfaa..81bd02ae70 100644
--- a/src/core/ext/transport/chttp2/transport/frame_ping.c
+++ b/src/core/ext/transport/chttp2/transport/frame_ping.c
@@ -117,7 +117,8 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
               t->ping_acks, t->ping_ack_capacity * sizeof(*t->ping_acks));
         }
         t->ping_acks[t->ping_ack_count++] = p->opaque_8bytes;
-        grpc_chttp2_initiate_write(exec_ctx, t, "ping response");
+        grpc_chttp2_initiate_write(exec_ctx, t,
+                                   GRPC_CHTTP2_INITIATE_WRITE_PING_RESPONSE);
       }
     }
   }
diff --git a/src/core/ext/transport/chttp2/transport/frame_window_update.c b/src/core/ext/transport/chttp2/transport/frame_window_update.c
index c94f7725bf..c9ab8d1b50 100644
--- a/src/core/ext/transport/chttp2/transport/frame_window_update.c
+++ b/src/core/ext/transport/chttp2/transport/frame_window_update.c
@@ -99,8 +99,10 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
         grpc_chttp2_flowctl_recv_stream_update(
             &t->flow_control, &s->flow_control, received_update);
         if (grpc_chttp2_list_remove_stalled_by_stream(t, s)) {
-          grpc_chttp2_become_writable(exec_ctx, t, s, true,
-                                      "stream.read_flow_control");
+          grpc_chttp2_mark_stream_writable(exec_ctx, t, s);
+          grpc_chttp2_initiate_write(
+              exec_ctx, t,
+              GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE);
         }
       }
     } else {
@@ -109,7 +111,9 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
                                                 received_update);
       bool is_zero = t->flow_control.remote_window <= 0;
       if (was_zero && !is_zero) {
-        grpc_chttp2_initiate_write(exec_ctx, t, "new_global_flow_control");
+        grpc_chttp2_initiate_write(
+            exec_ctx, t,
+            GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED);
       }
     }
   }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.c b/src/core/ext/transport/chttp2/transport/hpack_parser.c
index 82ff2c8e2c..901e7413c0 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.c
@@ -1649,7 +1649,8 @@ static void force_client_rst_stream(grpc_exec_ctx *exec_ctx, void *sp,
     grpc_slice_buffer_add(
         &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_HTTP2_NO_ERROR,
                                                 &s->stats.outgoing));
-    grpc_chttp2_initiate_write(exec_ctx, t, "force_rst_stream");
+    grpc_chttp2_initiate_write(exec_ctx, t,
+                               GRPC_CHTTP2_INITIATE_WRITE_FORCE_RST_STREAM);
     grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, true, GRPC_ERROR_NONE);
   }
   GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "final_rst");
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index 0fbedd1e56..c2dfce7c9c 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -79,6 +79,33 @@ typedef enum {
   GRPC_CHTTP2_PCL_COUNT /* must be last */
 } grpc_chttp2_ping_closure_list;
 
+typedef enum {
+  GRPC_CHTTP2_INITIATE_WRITE_INITIAL_WRITE,
+  GRPC_CHTTP2_INITIATE_WRITE_START_NEW_STREAM,
+  GRPC_CHTTP2_INITIATE_WRITE_SEND_MESSAGE,
+  GRPC_CHTTP2_INITIATE_WRITE_SEND_INITIAL_METADATA,
+  GRPC_CHTTP2_INITIATE_WRITE_SEND_TRAILING_METADATA,
+  GRPC_CHTTP2_INITIATE_WRITE_RETRY_SEND_PING,
+  GRPC_CHTTP2_INITIATE_WRITE_CONTINUE_PINGS,
+  GRPC_CHTTP2_INITIATE_WRITE_GOAWAY_SENT,
+  GRPC_CHTTP2_INITIATE_WRITE_RST_STREAM,
+  GRPC_CHTTP2_INITIATE_WRITE_CLOSE_FROM_API,
+  GRPC_CHTTP2_INITIATE_WRITE_STREAM_FLOW_CONTROL,
+  GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL,
+  GRPC_CHTTP2_INITIATE_WRITE_SEND_SETTINGS,
+  GRPC_CHTTP2_INITIATE_WRITE_BDP_ESTIMATOR_PING,
+  GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_SETTING,
+  GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE,
+  GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING,
+  GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING,
+  GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED,
+  GRPC_CHTTP2_INITIATE_WRITE_PING_RESPONSE,
+  GRPC_CHTTP2_INITIATE_WRITE_FORCE_RST_STREAM,
+} grpc_chttp2_initiate_write_reason;
+
+const char *grpc_chttp2_initiate_write_reason_string(
+    grpc_chttp2_initiate_write_reason reason);
+
 typedef struct {
   grpc_closure_list lists[GRPC_CHTTP2_PCL_COUNT];
   uint64_t inflight_id;
@@ -599,7 +626,8 @@ struct grpc_chttp2_stream {
     The actual call chain is documented in the implementation of this function.
     */
 void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t, const char *reason);
+                                grpc_chttp2_transport *t,
+                                grpc_chttp2_initiate_write_reason reason);
 
 typedef struct {
   /** are we writing? */
@@ -851,10 +879,9 @@ void grpc_chttp2_add_ping_strike(grpc_exec_ctx *exec_ctx,
 
 /** add a ref to the stream and add it to the writable list;
     ref will be dropped in writing.c */
-void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
-                                 grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s,
-                                 bool also_initiate_write, const char *reason);
+void grpc_chttp2_mark_stream_writable(grpc_exec_ctx *exec_ctx,
+                                      grpc_chttp2_transport *t,
+                                      grpc_chttp2_stream *s);
 
 void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_transport *t, grpc_chttp2_stream *s,
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index 3fa38db4db..3ded801985 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -201,9 +201,8 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
 
   if (t->flow_control.remote_window > 0) {
     while (grpc_chttp2_list_pop_stalled_by_transport(t, &s)) {
-      if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s) &&
-          stream_ref_if_not_destroyed(&s->refcount->refs)) {
-        grpc_chttp2_initiate_write(exec_ctx, t, "transport.read_flow_control");
+      if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s)) {
+        stream_ref_if_not_destroyed(&s->refcount->refs);
       }
     }
   }
-- 
cgit v1.2.3


From 3ad5c74311b6f603ed590c5330ac71d3387c7710 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Thu, 14 Sep 2017 11:29:30 -0700
Subject: Fix errant change

---
 src/core/ext/transport/chttp2/transport/chttp2_transport.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/core/ext/transport')

diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 7e392b6d63..79a9ed827f 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -3006,7 +3006,8 @@ grpc_chttp2_incoming_byte_stream *grpc_chttp2_incoming_byte_stream_create(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t, grpc_chttp2_stream *s,
     uint32_t frame_size, uint32_t flags) {
   grpc_chttp2_incoming_byte_stream *incoming_byte_stream =
-      gpr_malloc(sizeof(*incoming_byte_stream));
+      (grpc_chttp2_incoming_byte_stream *)gpr_malloc(
+          sizeof(*incoming_byte_stream));
   incoming_byte_stream->base.length = frame_size;
   incoming_byte_stream->remaining_bytes = frame_size;
   incoming_byte_stream->base.flags = flags;
-- 
cgit v1.2.3


From 9eb8672bbe02dc47f2f667b99670b215d7431ef0 Mon Sep 17 00:00:00 2001
From: Yash Tibrewal <yashkt@google.com>
Date: Sun, 17 Sep 2017 23:43:30 -0700
Subject: Removing deprecated string to char * conversions

---
 include/grpc/compression.h                         |  4 ++--
 src/core/ext/census/base_resources.c               | 28 +++++++++++-----------
 .../ext/filters/client_channel/client_channel.c    | 13 +++++-----
 .../client_channel/client_channel_factory.c        |  2 +-
 .../filters/client_channel/client_channel_plugin.c |  4 ++--
 src/core/ext/filters/client_channel/http_proxy.c   |  6 ++---
 .../client_channel/lb_policy/grpclb/grpclb.c       |  4 ++--
 .../lb_policy/round_robin/round_robin.c            |  2 +-
 .../ext/filters/client_channel/lb_policy_factory.c |  2 +-
 .../resolver/dns/c_ares/dns_resolver_ares.c        |  4 ++--
 .../client_channel/resolver/fake/fake_resolver.c   |  2 +-
 src/core/ext/filters/client_channel/subchannel.c   |  2 +-
 .../message_compress/message_compress_filter.c     |  4 ++--
 .../load_reporting/server_load_reporting_plugin.c  |  3 ++-
 .../chttp2/client/insecure/channel_create.c        |  2 +-
 .../chttp2/client/insecure/channel_create_posix.c  |  2 +-
 src/core/ext/transport/inproc/inproc_transport.c   |  4 ++--
 src/core/lib/channel/channel_args.c                | 12 +++++-----
 src/core/lib/channel/channel_stack.h               |  2 +-
 src/core/lib/compression/compression.c             |  4 ++--
 src/core/lib/debug/trace.h                         |  2 +-
 src/core/lib/iomgr/error.c                         |  2 +-
 src/core/lib/iomgr/resolve_address_posix.c         |  2 +-
 src/core/lib/support/log_linux.c                   |  2 +-
 src/core/lib/support/string.c                      |  2 +-
 src/core/lib/surface/call.c                        |  8 +++----
 src/core/lib/transport/transport_op_string.c       |  2 +-
 src/cpp/client/client_context.cc                   |  2 +-
 src/cpp/server/server_context.cc                   |  2 +-
 test/core/compression/algorithm_test.c             |  2 +-
 test/core/compression/compression_test.c           |  2 +-
 test/core/compression/message_compress_test.c      |  2 +-
 test/core/end2end/tests/compressed_payload.c       |  2 +-
 .../tests/stream_compression_compressed_payload.c  |  2 +-
 34 files changed, 71 insertions(+), 69 deletions(-)

(limited to 'src/core/ext/transport')

diff --git a/include/grpc/compression.h b/include/grpc/compression.h
index 3a8de4b7b8..13a8dd66ad 100644
--- a/include/grpc/compression.h
+++ b/include/grpc/compression.h
@@ -44,13 +44,13 @@ int grpc_stream_compression_algorithm_parse(
  * algorithm. Note that \a name is statically allocated and must *not* be freed.
  * Returns 1 upon success, 0 otherwise. */
 GRPCAPI int grpc_compression_algorithm_name(
-    grpc_compression_algorithm algorithm, char **name);
+    grpc_compression_algorithm algorithm, const char **name);
 
 /** Updates \a name with the encoding name corresponding to a valid \a
  * algorithm. Note that \a name is statically allocated and must *not* be freed.
  * Returns 1 upon success, 0 otherwise. */
 GRPCAPI int grpc_stream_compression_algorithm_name(
-    grpc_stream_compression_algorithm algorithm, char **name);
+    grpc_stream_compression_algorithm algorithm, const char **name);
 
 /** Returns the compression algorithm corresponding to \a level for the
  * compression algorithms encoded in the \a accepted_encodings bitset.
diff --git a/src/core/ext/census/base_resources.c b/src/core/ext/census/base_resources.c
index 2114bf04cd..1f2bb39fe0 100644
--- a/src/core/ext/census/base_resources.c
+++ b/src/core/ext/census/base_resources.c
@@ -37,20 +37,20 @@
 void define_base_resources() {
   google_census_Resource_BasicUnit numerator =
       google_census_Resource_BasicUnit_SECS;
-  resource r = {"client_rpc_latency",             // name
-                "Client RPC latency in seconds",  // description
-                0,                                // prefix
-                1,                                // n_numerators
-                &numerator,                       // numerators
-                0,                                // n_denominators
-                NULL};                            // denominators
+  resource r = {(char *)"client_rpc_latency",             // name
+                (char *)"Client RPC latency in seconds",  // description
+                0,                                        // prefix
+                1,                                        // n_numerators
+                &numerator,                               // numerators
+                0,                                        // n_denominators
+                NULL};                                    // denominators
   define_resource(&r);
-  r = (resource){"server_rpc_latency",             // name
-                 "Server RPC latency in seconds",  // description
-                 0,                                // prefix
-                 1,                                // n_numerators
-                 &numerator,                       // numerators
-                 0,                                // n_denominators
-                 NULL};                            // denominators
+  r = (resource){(char *)"server_rpc_latency",             // name
+                 (char *)"Server RPC latency in seconds",  // description
+                 0,                                        // prefix
+                 1,                                        // n_numerators
+                 &numerator,                               // numerators
+                 0,                                        // n_denominators
+                 NULL};                                    // denominators
   define_resource(&r);
 }
diff --git a/src/core/ext/filters/client_channel/client_channel.c b/src/core/ext/filters/client_channel/client_channel.c
index 129d0f368b..016199b1f4 100644
--- a/src/core/ext/filters/client_channel/client_channel.c
+++ b/src/core/ext/filters/client_channel/client_channel.c
@@ -375,7 +375,7 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
   }
   // Extract the following fields from the resolver result, if non-NULL.
   bool lb_policy_updated = false;
-  char *lb_policy_name = NULL;
+  char *lb_policy_name_dup = NULL;
   bool lb_policy_name_changed = false;
   grpc_lb_policy *new_lb_policy = NULL;
   char *service_config_json = NULL;
@@ -383,6 +383,7 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
   grpc_slice_hash_table *method_params_table = NULL;
   if (chand->resolver_result != NULL) {
     // Find LB policy name.
+    const char *lb_policy_name = NULL;
     const grpc_arg *channel_arg =
         grpc_channel_args_find(chand->resolver_result, GRPC_ARG_LB_POLICY_NAME);
     if (channel_arg != NULL) {
@@ -473,7 +474,7 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
     // Before we clean up, save a copy of lb_policy_name, since it might
     // be pointing to data inside chand->resolver_result.
     // The copy will be saved in chand->lb_policy_name below.
-    lb_policy_name = gpr_strdup(lb_policy_name);
+    lb_policy_name_dup = gpr_strdup(lb_policy_name);
     grpc_channel_args_destroy(exec_ctx, chand->resolver_result);
     chand->resolver_result = NULL;
   }
@@ -481,8 +482,8 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
     gpr_log(GPR_DEBUG,
             "chand=%p: resolver result: lb_policy_name=\"%s\"%s, "
             "service_config=\"%s\"",
-            chand, lb_policy_name, lb_policy_name_changed ? " (changed)" : "",
-            service_config_json);
+            chand, lb_policy_name_dup,
+            lb_policy_name_changed ? " (changed)" : "", service_config_json);
   }
   // Now swap out fields in chand.  Note that the new values may still
   // be NULL if (e.g.) the resolver failed to return results or the
@@ -490,9 +491,9 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
   //
   // First, swap out the data used by cc_get_channel_info().
   gpr_mu_lock(&chand->info_mu);
-  if (lb_policy_name != NULL) {
+  if (lb_policy_name_dup != NULL) {
     gpr_free(chand->info_lb_policy_name);
-    chand->info_lb_policy_name = lb_policy_name;
+    chand->info_lb_policy_name = lb_policy_name_dup;
   }
   if (service_config_json != NULL) {
     gpr_free(chand->info_service_config_json);
diff --git a/src/core/ext/filters/client_channel/client_channel_factory.c b/src/core/ext/filters/client_channel/client_channel_factory.c
index e8aa4cda29..57eac8f875 100644
--- a/src/core/ext/filters/client_channel/client_channel_factory.c
+++ b/src/core/ext/filters/client_channel/client_channel_factory.c
@@ -63,6 +63,6 @@ static const grpc_arg_pointer_vtable factory_arg_vtable = {
 
 grpc_arg grpc_client_channel_factory_create_channel_arg(
     grpc_client_channel_factory* factory) {
-  return grpc_channel_arg_pointer_create(GRPC_ARG_CLIENT_CHANNEL_FACTORY,
+  return grpc_channel_arg_pointer_create((char*)GRPC_ARG_CLIENT_CHANNEL_FACTORY,
                                          factory, &factory_arg_vtable);
 }
diff --git a/src/core/ext/filters/client_channel/client_channel_plugin.c b/src/core/ext/filters/client_channel/client_channel_plugin.c
index c32e83d012..1f71c5a7f9 100644
--- a/src/core/ext/filters/client_channel/client_channel_plugin.c
+++ b/src/core/ext/filters/client_channel/client_channel_plugin.c
@@ -54,8 +54,8 @@ static bool set_default_host_if_unset(grpc_exec_ctx *exec_ctx,
   char *default_authority = grpc_get_default_authority(
       exec_ctx, grpc_channel_stack_builder_get_target(builder));
   if (default_authority != NULL) {
-    grpc_arg arg = grpc_channel_arg_string_create(GRPC_ARG_DEFAULT_AUTHORITY,
-                                                  default_authority);
+    grpc_arg arg = grpc_channel_arg_string_create(
+        (char *)GRPC_ARG_DEFAULT_AUTHORITY, default_authority);
     grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
     grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
                                                      new_args);
diff --git a/src/core/ext/filters/client_channel/http_proxy.c b/src/core/ext/filters/client_channel/http_proxy.c
index ef3512ed83..0c3b009e44 100644
--- a/src/core/ext/filters/client_channel/http_proxy.c
+++ b/src/core/ext/filters/client_channel/http_proxy.c
@@ -157,7 +157,7 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
   }
   grpc_arg args_to_add[2];
   args_to_add[0] = grpc_channel_arg_string_create(
-      GRPC_ARG_HTTP_CONNECT_SERVER,
+      (char*)GRPC_ARG_HTTP_CONNECT_SERVER,
       uri->path[0] == '/' ? uri->path + 1 : uri->path);
   if (user_cred != NULL) {
     /* Use base64 encoding for user credentials as stated in RFC 7617 */
@@ -166,8 +166,8 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
     char* header;
     gpr_asprintf(&header, "Proxy-Authorization:Basic %s", encoded_user_cred);
     gpr_free(encoded_user_cred);
-    args_to_add[1] =
-        grpc_channel_arg_string_create(GRPC_ARG_HTTP_CONNECT_HEADERS, header);
+    args_to_add[1] = grpc_channel_arg_string_create(
+        (char*)GRPC_ARG_HTTP_CONNECT_HEADERS, header);
     *new_args = grpc_channel_args_copy_and_add(args, args_to_add, 2);
     gpr_free(header);
   } else {
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
index a776a07d99..c4c4973b2d 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c
@@ -1830,8 +1830,8 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
 
   // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
   // since we use this to trigger the client_load_reporting filter.
-  grpc_arg new_arg =
-      grpc_channel_arg_string_create(GRPC_ARG_LB_POLICY_NAME, "grpclb");
+  grpc_arg new_arg = grpc_channel_arg_string_create(
+      (char *)GRPC_ARG_LB_POLICY_NAME, (char *)"grpclb");
   static const char *args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME};
   glb_policy->args = grpc_channel_args_copy_and_add_and_remove(
       args->args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
index 8ac1a46abd..a3a62e9f3c 100644
--- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.c
@@ -589,7 +589,7 @@ static void rr_connectivity_changed_locked(grpc_exec_ctx *exec_ctx, void *arg,
   // Dispose of outdated subchannel lists.
   if (sd->subchannel_list != p->subchannel_list &&
       sd->subchannel_list != p->latest_pending_subchannel_list) {
-    char *reason = NULL;
+    const char *reason = NULL;
     if (sd->subchannel_list->shutting_down) {
       reason = "sl_outdated_straggler";
       rr_subchannel_list_unref(exec_ctx, sd->subchannel_list, reason);
diff --git a/src/core/ext/filters/client_channel/lb_policy_factory.c b/src/core/ext/filters/client_channel/lb_policy_factory.c
index acf5929746..4d1405454c 100644
--- a/src/core/ext/filters/client_channel/lb_policy_factory.c
+++ b/src/core/ext/filters/client_channel/lb_policy_factory.c
@@ -141,7 +141,7 @@ static const grpc_arg_pointer_vtable lb_addresses_arg_vtable = {
 grpc_arg grpc_lb_addresses_create_channel_arg(
     const grpc_lb_addresses* addresses) {
   return grpc_channel_arg_pointer_create(
-      GRPC_ARG_LB_ADDRESSES, (void*)addresses, &lb_addresses_arg_vtable);
+      (char*)GRPC_ARG_LB_ADDRESSES, (void*)addresses, &lb_addresses_arg_vtable);
 }
 
 grpc_lb_addresses* grpc_lb_addresses_find_channel_arg(
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
index 371c59b8cf..9bb229ad95 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.c
@@ -249,7 +249,7 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
                 service_config_string);
         args_to_remove[num_args_to_remove++] = GRPC_ARG_SERVICE_CONFIG;
         new_args[num_args_to_add++] = grpc_channel_arg_string_create(
-            GRPC_ARG_SERVICE_CONFIG, service_config_string);
+            (char *)GRPC_ARG_SERVICE_CONFIG, service_config_string);
         service_config = grpc_service_config_create(service_config_string);
         if (service_config != NULL) {
           const char *lb_policy_name =
@@ -257,7 +257,7 @@ static void dns_ares_on_resolved_locked(grpc_exec_ctx *exec_ctx, void *arg,
           if (lb_policy_name != NULL) {
             args_to_remove[num_args_to_remove++] = GRPC_ARG_LB_POLICY_NAME;
             new_args[num_args_to_add++] = grpc_channel_arg_string_create(
-                GRPC_ARG_LB_POLICY_NAME, (char *)lb_policy_name);
+                (char *)GRPC_ARG_LB_POLICY_NAME, (char *)lb_policy_name);
           }
         }
       }
diff --git a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c
index c4676e0299..69ea440ae6 100644
--- a/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c
+++ b/src/core/ext/filters/client_channel/resolver/fake/fake_resolver.c
@@ -210,7 +210,7 @@ grpc_arg grpc_fake_resolver_response_generator_arg(
     grpc_fake_resolver_response_generator* generator) {
   grpc_arg arg;
   arg.type = GRPC_ARG_POINTER;
-  arg.key = GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR;
+  arg.key = (char*)GRPC_ARG_FAKE_RESOLVER_RESPONSE_GENERATOR;
   arg.value.pointer.p = generator;
   arg.value.pointer.vtable = &response_generator_arg_vtable;
   return arg;
diff --git a/src/core/ext/filters/client_channel/subchannel.c b/src/core/ext/filters/client_channel/subchannel.c
index bc9c3cc782..40a51c72d6 100644
--- a/src/core/ext/filters/client_channel/subchannel.c
+++ b/src/core/ext/filters/client_channel/subchannel.c
@@ -811,6 +811,6 @@ const char *grpc_get_subchannel_address_uri_arg(const grpc_channel_args *args) {
 
 grpc_arg grpc_create_subchannel_address_arg(const grpc_resolved_address *addr) {
   return grpc_channel_arg_string_create(
-      GRPC_ARG_SUBCHANNEL_ADDRESS,
+      (char *)GRPC_ARG_SUBCHANNEL_ADDRESS,
       addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup(""));
 }
diff --git a/src/core/ext/filters/http/message_compress/message_compress_filter.c b/src/core/ext/filters/http/message_compress/message_compress_filter.c
index 0145dffab0..f785e1355d 100644
--- a/src/core/ext/filters/http/message_compress/message_compress_filter.c
+++ b/src/core/ext/filters/http/message_compress/message_compress_filter.c
@@ -244,7 +244,7 @@ static void finish_send_message(grpc_exec_ctx *exec_ctx,
                                         &calld->slices, &tmp);
   if (did_compress) {
     if (GRPC_TRACER_ON(grpc_compression_trace)) {
-      char *algo_name;
+      const char *algo_name;
       const size_t before_size = calld->slices.length;
       const size_t after_size = tmp.length;
       const float savings_ratio = 1.0f - (float)after_size / (float)before_size;
@@ -258,7 +258,7 @@ static void finish_send_message(grpc_exec_ctx *exec_ctx,
     send_flags |= GRPC_WRITE_INTERNAL_COMPRESS;
   } else {
     if (GRPC_TRACER_ON(grpc_compression_trace)) {
-      char *algo_name;
+      const char *algo_name;
       GPR_ASSERT(grpc_compression_algorithm_name(calld->compression_algorithm,
                                                  &algo_name));
       gpr_log(GPR_DEBUG,
diff --git a/src/core/ext/filters/load_reporting/server_load_reporting_plugin.c b/src/core/ext/filters/load_reporting/server_load_reporting_plugin.c
index f56afd27d2..2486ead427 100644
--- a/src/core/ext/filters/load_reporting/server_load_reporting_plugin.c
+++ b/src/core/ext/filters/load_reporting/server_load_reporting_plugin.c
@@ -55,7 +55,8 @@ static bool maybe_add_server_load_reporting_filter(
 }
 
 grpc_arg grpc_load_reporting_enable_arg() {
-  return grpc_channel_arg_integer_create(GRPC_ARG_ENABLE_LOAD_REPORTING, 1);
+  return grpc_channel_arg_integer_create((char *)GRPC_ARG_ENABLE_LOAD_REPORTING,
+                                         1);
 }
 
 /* Plugin registration */
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 cccb347bf1..6410a6043d 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
@@ -55,7 +55,7 @@ static grpc_channel *client_channel_factory_create_channel(
   }
   // Add channel arg containing the server URI.
   grpc_arg arg = grpc_channel_arg_string_create(
-      GRPC_ARG_SERVER_URI,
+      (char *)GRPC_ARG_SERVER_URI,
       grpc_resolver_factory_add_default_prefix_if_needed(exec_ctx, target));
   const char *to_remove[] = {GRPC_ARG_SERVER_URI};
   grpc_channel_args *new_args =
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 0346d50b6c..dd88136f7b 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
@@ -42,7 +42,7 @@ grpc_channel *grpc_insecure_channel_create_from_fd(
                  (target, fd, args));
 
   grpc_arg default_authority_arg = grpc_channel_arg_string_create(
-      GRPC_ARG_DEFAULT_AUTHORITY, "test.authority");
+      (char *)GRPC_ARG_DEFAULT_AUTHORITY, (char *)"test.authority");
   grpc_channel_args *final_args =
       grpc_channel_args_copy_and_add(args, &default_authority_arg, 1);
 
diff --git a/src/core/ext/transport/inproc/inproc_transport.c b/src/core/ext/transport/inproc/inproc_transport.c
index cd3e76a0b5..31739d07dd 100644
--- a/src/core/ext/transport/inproc/inproc_transport.c
+++ b/src/core/ext/transport/inproc/inproc_transport.c
@@ -1263,8 +1263,8 @@ grpc_channel *grpc_inproc_channel_create(grpc_server *server,
 
   grpc_arg default_authority_arg;
   default_authority_arg.type = GRPC_ARG_STRING;
-  default_authority_arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
-  default_authority_arg.value.string = "inproc.authority";
+  default_authority_arg.key = (char *)GRPC_ARG_DEFAULT_AUTHORITY;
+  default_authority_arg.value.string = (char *)"inproc.authority";
   grpc_channel_args *client_args =
       grpc_channel_args_copy_and_add(args, &default_authority_arg, 1);
 
diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.c
index 9215707f1c..30248b3c60 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/src/core/lib/channel/channel_args.c
@@ -243,7 +243,7 @@ grpc_channel_args *grpc_channel_args_set_compression_algorithm(
   GPR_ASSERT(algorithm < GRPC_COMPRESS_ALGORITHMS_COUNT);
   grpc_arg tmp;
   tmp.type = GRPC_ARG_INTEGER;
-  tmp.key = GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM;
+  tmp.key = (char *)GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM;
   tmp.value.integer = algorithm;
   return grpc_channel_args_copy_and_add(a, &tmp, 1);
 }
@@ -253,7 +253,7 @@ grpc_channel_args *grpc_channel_args_set_stream_compression_algorithm(
   GPR_ASSERT(algorithm < GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT);
   grpc_arg tmp;
   tmp.type = GRPC_ARG_INTEGER;
-  tmp.key = GRPC_STREAM_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM;
+  tmp.key = (char *)GRPC_STREAM_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM;
   tmp.value.integer = algorithm;
   return grpc_channel_args_copy_and_add(a, &tmp, 1);
 }
@@ -308,7 +308,7 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
 
   if (grpc_channel_args_get_compression_algorithm(*a) == algorithm &&
       state == 0) {
-    char *algo_name = NULL;
+    const char *algo_name = NULL;
     GPR_ASSERT(grpc_compression_algorithm_name(algorithm, &algo_name) != 0);
     gpr_log(GPR_ERROR,
             "Tried to disable default compression algorithm '%s'. The "
@@ -324,7 +324,7 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
     /* create a new arg */
     grpc_arg tmp;
     tmp.type = GRPC_ARG_INTEGER;
-    tmp.key = GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET;
+    tmp.key = (char *)GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET;
     /* all enabled by default */
     tmp.value.integer = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
     if (state != 0) {
@@ -349,7 +349,7 @@ grpc_channel_args *grpc_channel_args_stream_compression_algorithm_set_state(
 
   if (grpc_channel_args_get_stream_compression_algorithm(*a) == algorithm &&
       state == 0) {
-    char *algo_name = NULL;
+    const char *algo_name = NULL;
     GPR_ASSERT(grpc_stream_compression_algorithm_name(algorithm, &algo_name) !=
                0);
     gpr_log(GPR_ERROR,
@@ -366,7 +366,7 @@ grpc_channel_args *grpc_channel_args_stream_compression_algorithm_set_state(
     /* create a new arg */
     grpc_arg tmp;
     tmp.type = GRPC_ARG_INTEGER;
-    tmp.key = GRPC_STREAM_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET;
+    tmp.key = (char *)GRPC_STREAM_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET;
     /* all enabled by default */
     tmp.value.integer = (1u << GRPC_STREAM_COMPRESS_ALGORITHMS_COUNT) - 1;
     if (state != 0) {
diff --git a/src/core/lib/channel/channel_stack.h b/src/core/lib/channel/channel_stack.h
index ae1cac31f7..f0de80f0c0 100644
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@@ -281,7 +281,7 @@ grpc_channel_stack *grpc_channel_stack_from_top_element(
 /* Given the top element of a call stack, get the call stack itself */
 grpc_call_stack *grpc_call_stack_from_top_element(grpc_call_element *elem);
 
-void grpc_call_log_op(char *file, int line, gpr_log_severity severity,
+void grpc_call_log_op(const char *file, int line, gpr_log_severity severity,
                       grpc_call_element *elem,
                       grpc_transport_stream_op_batch *op);
 
diff --git a/src/core/lib/compression/compression.c b/src/core/lib/compression/compression.c
index ec84c01811..1cfac23129 100644
--- a/src/core/lib/compression/compression.c
+++ b/src/core/lib/compression/compression.c
@@ -60,7 +60,7 @@ int grpc_stream_compression_algorithm_parse(
 }
 
 int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
-                                    char **name) {
+                                    const char **name) {
   GRPC_API_TRACE("grpc_compression_algorithm_parse(algorithm=%d, name=%p)", 2,
                  ((int)algorithm, name));
   switch (algorithm) {
@@ -80,7 +80,7 @@ int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
 }
 
 int grpc_stream_compression_algorithm_name(
-    grpc_stream_compression_algorithm algorithm, char **name) {
+    grpc_stream_compression_algorithm algorithm, const char **name) {
   GRPC_API_TRACE(
       "grpc_stream_compression_algorithm_parse(algorithm=%d, name=%p)", 2,
       ((int)algorithm, name));
diff --git a/src/core/lib/debug/trace.h b/src/core/lib/debug/trace.h
index dd9e6a30fe..64f2e3fc33 100644
--- a/src/core/lib/debug/trace.h
+++ b/src/core/lib/debug/trace.h
@@ -35,7 +35,7 @@ typedef struct {
 #else
   bool value;
 #endif
-  char *name;
+  const char *name;
 } grpc_tracer_flag;
 
 #ifdef GRPC_THREADSAFE_TRACER
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index d5e00a8f64..aa05501537 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -641,7 +641,7 @@ static char *key_time(grpc_error_times which) {
 
 static char *fmt_time(gpr_timespec tm) {
   char *out;
-  char *pfx = "!!";
+  const char *pfx = "!!";
   switch (tm.clock_type) {
     case GPR_CLOCK_MONOTONIC:
       pfx = "@monotonic:";
diff --git a/src/core/lib/iomgr/resolve_address_posix.c b/src/core/lib/iomgr/resolve_address_posix.c
index 082e3b7947..60cfeebd47 100644
--- a/src/core/lib/iomgr/resolve_address_posix.c
+++ b/src/core/lib/iomgr/resolve_address_posix.c
@@ -85,7 +85,7 @@ static grpc_error *blocking_resolve_address_impl(
 
   if (s != 0) {
     /* Retry if well-known service name is recognized */
-    char *svc[][2] = {{"http", "80"}, {"https", "443"}};
+    const char *svc[][2] = {{"http", "80"}, {"https", "443"}};
     for (i = 0; i < GPR_ARRAY_SIZE(svc); i++) {
       if (strcmp(port, svc[i][0]) == 0) {
         GRPC_SCHEDULING_START_BLOCKING_REGION;
diff --git a/src/core/lib/support/log_linux.c b/src/core/lib/support/log_linux.c
index 61d2346427..7755018693 100644
--- a/src/core/lib/support/log_linux.c
+++ b/src/core/lib/support/log_linux.c
@@ -57,7 +57,7 @@ void gpr_log(const char *file, int line, gpr_log_severity severity,
 }
 
 void gpr_default_log(gpr_log_func_args *args) {
-  char *final_slash;
+  const char *final_slash;
   char *prefix;
   const char *display_file;
   char time_buffer[64];
diff --git a/src/core/lib/support/string.c b/src/core/lib/support/string.c
index 523e43445b..6b172df82f 100644
--- a/src/core/lib/support/string.c
+++ b/src/core/lib/support/string.c
@@ -276,7 +276,7 @@ static void add_string_to_split(const char *beg, const char *end, char ***strs,
 
 void gpr_string_split(const char *input, const char *sep, char ***strs,
                       size_t *nstrs) {
-  char *next;
+  const char *next;
   *strs = NULL;
   *nstrs = 0;
   size_t capstrs = 0;
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index e258719c4d..a41eb336d4 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -1511,7 +1511,7 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
     } else if (grpc_compression_options_is_stream_compression_algorithm_enabled(
                    &compression_options, algo) == 0) {
       /* check if algorithm is supported by current channel config */
-      char *algo_name = NULL;
+      const char *algo_name = NULL;
       grpc_stream_compression_algorithm_name(algo, &algo_name);
       gpr_asprintf(&error_msg, "Stream compression algorithm '%s' is disabled.",
                    algo_name);
@@ -1525,7 +1525,7 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
     if (!GPR_BITGET(call->stream_encodings_accepted_by_peer,
                     call->incoming_stream_compression_algorithm)) {
       if (GRPC_TRACER_ON(grpc_compression_trace)) {
-        char *algo_name = NULL;
+        const char *algo_name = NULL;
         grpc_stream_compression_algorithm_name(
             call->incoming_stream_compression_algorithm, &algo_name);
         gpr_log(
@@ -1552,7 +1552,7 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
     } else if (grpc_compression_options_is_algorithm_enabled(
                    &compression_options, algo) == 0) {
       /* check if algorithm is supported by current channel config */
-      char *algo_name = NULL;
+      const char *algo_name = NULL;
       grpc_compression_algorithm_name(algo, &algo_name);
       gpr_asprintf(&error_msg, "Compression algorithm '%s' is disabled.",
                    algo_name);
@@ -1568,7 +1568,7 @@ static void validate_filtered_metadata(grpc_exec_ctx *exec_ctx,
     if (!GPR_BITGET(call->encodings_accepted_by_peer,
                     call->incoming_compression_algorithm)) {
       if (GRPC_TRACER_ON(grpc_compression_trace)) {
-        char *algo_name = NULL;
+        const char *algo_name = NULL;
         grpc_compression_algorithm_name(call->incoming_compression_algorithm,
                                         &algo_name);
         gpr_log(GPR_ERROR,
diff --git a/src/core/lib/transport/transport_op_string.c b/src/core/lib/transport/transport_op_string.c
index 409a6c4103..858664715c 100644
--- a/src/core/lib/transport/transport_op_string.c
+++ b/src/core/lib/transport/transport_op_string.c
@@ -197,7 +197,7 @@ char *grpc_transport_op_string(grpc_transport_op *op) {
   return out;
 }
 
-void grpc_call_log_op(char *file, int line, gpr_log_severity severity,
+void grpc_call_log_op(const char *file, int line, gpr_log_severity severity,
                       grpc_call_element *elem,
                       grpc_transport_stream_op_batch *op) {
   char *str = grpc_transport_stream_op_batch_string(op);
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index 3af8bdc11a..40e95f3c05 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -96,7 +96,7 @@ void ClientContext::set_call(grpc_call* call,
 
 void ClientContext::set_compression_algorithm(
     grpc_compression_algorithm algorithm) {
-  char* algorithm_name = nullptr;
+  const char* algorithm_name = nullptr;
   if (!grpc_compression_algorithm_name(algorithm, &algorithm_name)) {
     gpr_log(GPR_ERROR, "Name for compression algorithm '%d' unknown.",
             algorithm);
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index 4913682f1d..d7876a000b 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -190,7 +190,7 @@ bool ServerContext::IsCancelled() const {
 
 void ServerContext::set_compression_algorithm(
     grpc_compression_algorithm algorithm) {
-  char* algorithm_name = NULL;
+  const char* algorithm_name = NULL;
   if (!grpc_compression_algorithm_name(algorithm, &algorithm_name)) {
     gpr_log(GPR_ERROR, "Name for compression algorithm '%d' unknown.",
             algorithm);
diff --git a/test/core/compression/algorithm_test.c b/test/core/compression/algorithm_test.c
index e37c8c3010..a11e6e90ac 100644
--- a/test/core/compression/algorithm_test.c
+++ b/test/core/compression/algorithm_test.c
@@ -35,7 +35,7 @@ static void test_algorithm_mesh(void) {
   gpr_log(GPR_DEBUG, "test_algorithm_mesh");
 
   for (i = 0; i < GRPC_COMPRESS_ALGORITHMS_COUNT; i++) {
-    char *name;
+    const char *name;
     grpc_compression_algorithm parsed;
     grpc_slice mdstr;
     grpc_mdelem mdelem;
diff --git a/test/core/compression/compression_test.c b/test/core/compression/compression_test.c
index 4b6026ec77..326a800300 100644
--- a/test/core/compression/compression_test.c
+++ b/test/core/compression/compression_test.c
@@ -57,7 +57,7 @@ static void test_compression_algorithm_parse(void) {
 
 static void test_compression_algorithm_name(void) {
   int success;
-  char *name;
+  const char *name;
   size_t i;
   const char *valid_names[] = {"identity", "gzip", "deflate"};
   const grpc_compression_algorithm valid_algorithms[] = {
diff --git a/test/core/compression/message_compress_test.c b/test/core/compression/message_compress_test.c
index fd692fe5a5..f7f4893dee 100644
--- a/test/core/compression/message_compress_test.c
+++ b/test/core/compression/message_compress_test.c
@@ -49,7 +49,7 @@ static void assert_passthrough(grpc_slice value,
   grpc_slice_buffer output;
   grpc_slice final;
   int was_compressed;
-  char *algorithm_name;
+  const char *algorithm_name;
 
   GPR_ASSERT(grpc_compression_algorithm_name(algorithm, &algorithm_name) != 0);
   gpr_log(
diff --git a/test/core/end2end/tests/compressed_payload.c b/test/core/end2end/tests/compressed_payload.c
index 429717a7be..639af15454 100644
--- a/test/core/end2end/tests/compressed_payload.c
+++ b/test/core/end2end/tests/compressed_payload.c
@@ -228,7 +228,7 @@ static void request_for_disabled_algorithm(
   /* with a certain error */
   GPR_ASSERT(status == expected_error);
 
-  char *algo_name = NULL;
+  const char *algo_name = NULL;
   GPR_ASSERT(grpc_compression_algorithm_name(algorithm_to_disable, &algo_name));
   char *expected_details = NULL;
   gpr_asprintf(&expected_details, "Compression algorithm '%s' is disabled.",
diff --git a/test/core/end2end/tests/stream_compression_compressed_payload.c b/test/core/end2end/tests/stream_compression_compressed_payload.c
index 11e7999a1c..5a69091a57 100644
--- a/test/core/end2end/tests/stream_compression_compressed_payload.c
+++ b/test/core/end2end/tests/stream_compression_compressed_payload.c
@@ -228,7 +228,7 @@ static void request_for_disabled_algorithm(
   /* with a certain error */
   GPR_ASSERT(status == expected_error);
 
-  char *algo_name = NULL;
+  const char *algo_name = NULL;
   GPR_ASSERT(
       grpc_stream_compression_algorithm_name(algorithm_to_disable, &algo_name));
   char *expected_details = NULL;
-- 
cgit v1.2.3


From 571fa0c5967a4e7a504e5ad5c495bb4a68953166 Mon Sep 17 00:00:00 2001
From: ncteisen <ncteisen@gmail.com>
Date: Mon, 11 Sep 2017 16:06:11 -0700
Subject: Add stream state tracer

---
 .../ext/transport/chttp2/transport/chttp2_plugin.c |  1 +
 .../transport/chttp2/transport/chttp2_transport.h  |  1 +
 .../ext/transport/chttp2/transport/stream_lists.c  | 52 +++++++++++++++-------
 3 files changed, 38 insertions(+), 16 deletions(-)

(limited to 'src/core/ext/transport')

diff --git a/src/core/ext/transport/chttp2/transport/chttp2_plugin.c b/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
index 78551df9c3..6d09953830 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_plugin.c
@@ -23,6 +23,7 @@
 void grpc_chttp2_plugin_init(void) {
   grpc_register_tracer(&grpc_http_trace);
   grpc_register_tracer(&grpc_flowctl_trace);
+  grpc_register_tracer(&grpc_trace_http2_stream_state);
 #ifndef NDEBUG
   grpc_register_tracer(&grpc_trace_chttp2_refcount);
 #endif
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.h b/src/core/ext/transport/chttp2/transport/chttp2_transport.h
index 0c4e2a91c0..55fb1a8343 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.h
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.h
@@ -25,6 +25,7 @@
 
 extern grpc_tracer_flag grpc_http_trace;
 extern grpc_tracer_flag grpc_flowctl_trace;
+extern grpc_tracer_flag grpc_trace_http2_stream_state;
 
 #ifndef NDEBUG
 extern grpc_tracer_flag grpc_trace_chttp2_refcount;
diff --git a/src/core/ext/transport/chttp2/transport/stream_lists.c b/src/core/ext/transport/chttp2/transport/stream_lists.c
index 7cc85dea9c..ee23b77efc 100644
--- a/src/core/ext/transport/chttp2/transport/stream_lists.c
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.c
@@ -20,6 +20,27 @@
 
 #include <grpc/support/log.h>
 
+static char *stream_list_id_string(grpc_chttp2_stream_list_id id) {
+  switch (id) {
+    case GRPC_CHTTP2_LIST_WRITABLE:
+      return "writable";
+    case GRPC_CHTTP2_LIST_WRITING:
+      return "writing";
+    case GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT:
+      return "stalled_by_transport";
+    case GRPC_CHTTP2_LIST_STALLED_BY_STREAM:
+      return "stalled_by_stream";
+    case GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY:
+      return "waiting_for_concurrency";
+    case STREAM_LIST_COUNT:
+      GPR_UNREACHABLE_CODE(return "unknown");
+  }
+  GPR_UNREACHABLE_CODE(return "unknown");
+}
+
+grpc_tracer_flag grpc_trace_http2_stream_state =
+    GRPC_TRACER_INITIALIZER(false, "http2_stream_state");
+
 /* core list management */
 
 static bool stream_list_empty(grpc_chttp2_transport *t,
@@ -44,6 +65,10 @@ static bool stream_list_pop(grpc_chttp2_transport *t,
     s->included[id] = 0;
   }
   *stream = s;
+  if (s && GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
+    gpr_log(GPR_DEBUG, "t[%p]: pop stream %d from %s", t, s->id,
+            stream_list_id_string(id));
+  }
   return s != 0;
 }
 
@@ -62,6 +87,10 @@ static void stream_list_remove(grpc_chttp2_transport *t, grpc_chttp2_stream *s,
   } else {
     t->lists[id].tail = s->links[id].prev;
   }
+  if (GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
+    gpr_log(GPR_DEBUG, "t[%p]: remove stream %d from %s", t, s->id,
+            stream_list_id_string(id));
+  }
 }
 
 static bool stream_list_maybe_remove(grpc_chttp2_transport *t,
@@ -90,6 +119,10 @@ static void stream_list_add_tail(grpc_chttp2_transport *t,
   }
   t->lists[id].tail = s;
   s->included[id] = 1;
+  if (GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
+    gpr_log(GPR_DEBUG, "t[%p]: add stream %d from %s", t, s->id,
+            stream_list_id_string(id));
+  }
 }
 
 static bool stream_list_add(grpc_chttp2_transport *t, grpc_chttp2_stream *s,
@@ -150,17 +183,12 @@ void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport *t,
 
 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s) {
-  GRPC_FLOW_CONTROL_IF_TRACING(
-      gpr_log(GPR_DEBUG, "stream %u stalled by transport", s->id));
   stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
 bool grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream **s) {
-  bool ret = stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
-  GRPC_FLOW_CONTROL_IF_TRACING(if (ret) gpr_log(
-      GPR_DEBUG, "stream %u un-stalled by transport", (*s)->id));
-  return ret;
+  return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
 void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
@@ -170,23 +198,15 @@ void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
 
 void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport *t,
                                             grpc_chttp2_stream *s) {
-  GRPC_FLOW_CONTROL_IF_TRACING(
-      gpr_log(GPR_DEBUG, "stream %u stalled by stream", s->id));
   stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
 }
 
 bool grpc_chttp2_list_pop_stalled_by_stream(grpc_chttp2_transport *t,
                                             grpc_chttp2_stream **s) {
-  bool ret = stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
-  GRPC_FLOW_CONTROL_IF_TRACING(
-      if (ret) gpr_log(GPR_DEBUG, "stream %u un-stalled by stream", (*s)->id));
-  return ret;
+  return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
 }
 
 bool grpc_chttp2_list_remove_stalled_by_stream(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s) {
-  bool ret = stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
-  GRPC_FLOW_CONTROL_IF_TRACING(
-      if (ret) gpr_log(GPR_DEBUG, "stream %u un-stalled by stream", s->id));
-  return ret;
+  return stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
 }
-- 
cgit v1.2.3


From 0252252fdd5c468079b3d5e32cc4516b02dccbcc Mon Sep 17 00:00:00 2001
From: ncteisen <ncteisen@gmail.com>
Date: Mon, 11 Sep 2017 18:01:23 -0700
Subject: Update env var documentation

---
 doc/environment_variables.md                           |  1 +
 src/core/ext/transport/chttp2/transport/stream_lists.c | 12 ++++++------
 2 files changed, 7 insertions(+), 6 deletions(-)

(limited to 'src/core/ext/transport')

diff --git a/doc/environment_variables.md b/doc/environment_variables.md
index b79cd97363..f90f1d5b10 100644
--- a/doc/environment_variables.md
+++ b/doc/environment_variables.md
@@ -50,6 +50,7 @@ some configuration as environment variables that can be set.
   - channel_stack_builder - traces information about channel stacks being built
   - executor - traces grpc's internal thread pool ('the executor')
   - http - traces state in the http2 transport engine
+  - http2_stream_state - traces all http2 stream state mutations.
   - http1 - traces HTTP/1.x operations performed by gRPC
   - inproc - traces the in-process transport
   - flowctl - traces http2 flow control
diff --git a/src/core/ext/transport/chttp2/transport/stream_lists.c b/src/core/ext/transport/chttp2/transport/stream_lists.c
index ee23b77efc..47cd22d177 100644
--- a/src/core/ext/transport/chttp2/transport/stream_lists.c
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.c
@@ -66,8 +66,8 @@ static bool stream_list_pop(grpc_chttp2_transport *t,
   }
   *stream = s;
   if (s && GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
-    gpr_log(GPR_DEBUG, "t[%p]: pop stream %d from %s", t, s->id,
-            stream_list_id_string(id));
+    gpr_log(GPR_DEBUG, "%p[%d][%s]: pop from %s", t, s->id,
+            t->is_client ? "cli" : "svr", stream_list_id_string(id));
   }
   return s != 0;
 }
@@ -88,8 +88,8 @@ static void stream_list_remove(grpc_chttp2_transport *t, grpc_chttp2_stream *s,
     t->lists[id].tail = s->links[id].prev;
   }
   if (GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
-    gpr_log(GPR_DEBUG, "t[%p]: remove stream %d from %s", t, s->id,
-            stream_list_id_string(id));
+    gpr_log(GPR_DEBUG, "%p[%d][%s]: remove from %s", t, s->id,
+            t->is_client ? "cli" : "svr", stream_list_id_string(id));
   }
 }
 
@@ -120,8 +120,8 @@ static void stream_list_add_tail(grpc_chttp2_transport *t,
   t->lists[id].tail = s;
   s->included[id] = 1;
   if (GRPC_TRACER_ON(grpc_trace_http2_stream_state)) {
-    gpr_log(GPR_DEBUG, "t[%p]: add stream %d from %s", t, s->id,
-            stream_list_id_string(id));
+    gpr_log(GPR_DEBUG, "%p[%d][%s]: add to %s", t, s->id,
+            t->is_client ? "cli" : "svr", stream_list_id_string(id));
   }
 }
 
-- 
cgit v1.2.3