Removing instances of exec_ctx being passed around in functions in

src/core. exec_ctx is now a thread_local pointer of type ExecCtx instead of
grpc_exec_ctx which is initialized whenever ExecCtx is instantiated. ExecCtx
also keeps track of the previous exec_ctx so that nesting of exec_ctx is
allowed. This means that there is only one exec_ctx being used at any
time. Also, grpc_exec_ctx_finish is called in the destructor of the
object, and the previous exec_ctx is restored to avoid breaking current
functionality. The code still explicitly calls grpc_exec_ctx_finish
because removing all such instances causes the code to break.

1 files changed, 55 insertions, 64 deletions

diff --git a/test/cpp/microbenchmarks/bm_metadata.cc b/test/cpp/microbenchmarks/bm_metadata.cc
index 360bbabe13..62a88f55b5 100644
--- a/test/cpp/microbenchmarks/bm_metadata.cc
+++ b/test/cpp/microbenchmarks/bm_metadata.cc
@@ -92,11 +92,11 @@ static void BM_MetadataFromNonInternedSlices(benchmark::State& state) {
   TrackCounters track_counters;
   gpr_slice k = grpc_slice_from_static_string("key");
   gpr_slice v = grpc_slice_from_static_string("value");
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataFromNonInternedSlices);
@@ -105,11 +105,11 @@ static void BM_MetadataFromInternedSlices(benchmark::State& state) {
   TrackCounters track_counters;
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_intern(grpc_slice_from_static_string("value"));
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   grpc_slice_unref(v);
   track_counters.Finish(state);
@@ -121,13 +121,13 @@ static void BM_MetadataFromInternedSlicesAlreadyInIndex(
   TrackCounters track_counters;
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_intern(grpc_slice_from_static_string("value"));
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_mdelem seed = grpc_mdelem_create(&exec_ctx, k, v, NULL);
+  ExecCtx _local_exec_ctx;
+  grpc_mdelem seed = grpc_mdelem_create(k, v, NULL);
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  GRPC_MDELEM_UNREF(&exec_ctx, seed);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(seed);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   grpc_slice_unref(v);
   track_counters.Finish(state);
@@ -138,11 +138,11 @@ static void BM_MetadataFromInternedKey(benchmark::State& state) {
   TrackCounters track_counters;
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_from_static_string("value");
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   track_counters.Finish(state);
 }
@@ -154,14 +154,12 @@ static void BM_MetadataFromNonInternedSlicesWithBackingStore(
   gpr_slice k = grpc_slice_from_static_string("key");
   gpr_slice v = grpc_slice_from_static_string("value");
   char backing_store[sizeof(grpc_mdelem_data)];
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(
-        &exec_ctx,
-        grpc_mdelem_create(&exec_ctx, k, v,
-                           reinterpret_cast<grpc_mdelem_data*>(backing_store)));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(
+        k, v, reinterpret_cast<grpc_mdelem_data*>(backing_store)));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataFromNonInternedSlicesWithBackingStore);
@@ -172,14 +170,12 @@ static void BM_MetadataFromInternedSlicesWithBackingStore(
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_intern(grpc_slice_from_static_string("value"));
   char backing_store[sizeof(grpc_mdelem_data)];
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(
-        &exec_ctx,
-        grpc_mdelem_create(&exec_ctx, k, v,
-                           reinterpret_cast<grpc_mdelem_data*>(backing_store)));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(
+        k, v, reinterpret_cast<grpc_mdelem_data*>(backing_store)));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   grpc_slice_unref(v);
   track_counters.Finish(state);
@@ -192,14 +188,12 @@ static void BM_MetadataFromInternedKeyWithBackingStore(
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_from_static_string("value");
   char backing_store[sizeof(grpc_mdelem_data)];
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(
-        &exec_ctx,
-        grpc_mdelem_create(&exec_ctx, k, v,
-                           reinterpret_cast<grpc_mdelem_data*>(backing_store)));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(
+        k, v, reinterpret_cast<grpc_mdelem_data*>(backing_store)));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   track_counters.Finish(state);
 }
@@ -209,11 +203,11 @@ static void BM_MetadataFromStaticMetadataStrings(benchmark::State& state) {
   TrackCounters track_counters;
   gpr_slice k = GRPC_MDSTR_STATUS;
   gpr_slice v = GRPC_MDSTR_200;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   track_counters.Finish(state);
 }
@@ -224,11 +218,11 @@ static void BM_MetadataFromStaticMetadataStringsNotIndexed(
   TrackCounters track_counters;
   gpr_slice k = GRPC_MDSTR_STATUS;
   gpr_slice v = GRPC_MDSTR_GZIP;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, grpc_mdelem_create(&exec_ctx, k, v, NULL));
+    GRPC_MDELEM_UNREF(grpc_mdelem_create(k, v, NULL));
   }
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_exec_ctx_finish();
   grpc_slice_unref(k);
   track_counters.Finish(state);
 }
@@ -237,16 +231,15 @@ BENCHMARK(BM_MetadataFromStaticMetadataStringsNotIndexed);
 static void BM_MetadataRefUnrefExternal(benchmark::State& state) {
   TrackCounters track_counters;
   char backing_store[sizeof(grpc_mdelem_data)];
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_mdelem el =
-      grpc_mdelem_create(&exec_ctx, grpc_slice_from_static_string("a"),
-                         grpc_slice_from_static_string("b"),
-                         reinterpret_cast<grpc_mdelem_data*>(backing_store));
+  ExecCtx _local_exec_ctx;
+  grpc_mdelem el = grpc_mdelem_create(
+      grpc_slice_from_static_string("a"), grpc_slice_from_static_string("b"),
+      reinterpret_cast<grpc_mdelem_data*>(backing_store));
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, GRPC_MDELEM_REF(el));
+    GRPC_MDELEM_UNREF(GRPC_MDELEM_REF(el));
   }
-  GRPC_MDELEM_UNREF(&exec_ctx, el);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(el);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataRefUnrefExternal);
@@ -254,47 +247,45 @@ BENCHMARK(BM_MetadataRefUnrefExternal);
 static void BM_MetadataRefUnrefInterned(benchmark::State& state) {
   TrackCounters track_counters;
   char backing_store[sizeof(grpc_mdelem_data)];
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ExecCtx _local_exec_ctx;
   gpr_slice k = grpc_slice_intern(grpc_slice_from_static_string("key"));
   gpr_slice v = grpc_slice_intern(grpc_slice_from_static_string("value"));
   grpc_mdelem el = grpc_mdelem_create(
-      &exec_ctx, k, v, reinterpret_cast<grpc_mdelem_data*>(backing_store));
+      k, v, reinterpret_cast<grpc_mdelem_data*>(backing_store));
   grpc_slice_unref(k);
   grpc_slice_unref(v);
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, GRPC_MDELEM_REF(el));
+    GRPC_MDELEM_UNREF(GRPC_MDELEM_REF(el));
   }
-  GRPC_MDELEM_UNREF(&exec_ctx, el);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(el);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataRefUnrefInterned);
 
 static void BM_MetadataRefUnrefAllocated(benchmark::State& state) {
   TrackCounters track_counters;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_mdelem el =
-      grpc_mdelem_create(&exec_ctx, grpc_slice_from_static_string("a"),
-                         grpc_slice_from_static_string("b"), NULL);
+  ExecCtx _local_exec_ctx;
+  grpc_mdelem el = grpc_mdelem_create(grpc_slice_from_static_string("a"),
+                                      grpc_slice_from_static_string("b"), NULL);
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, GRPC_MDELEM_REF(el));
+    GRPC_MDELEM_UNREF(GRPC_MDELEM_REF(el));
   }
-  GRPC_MDELEM_UNREF(&exec_ctx, el);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(el);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataRefUnrefAllocated);
 
 static void BM_MetadataRefUnrefStatic(benchmark::State& state) {
   TrackCounters track_counters;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_mdelem el =
-      grpc_mdelem_create(&exec_ctx, GRPC_MDSTR_STATUS, GRPC_MDSTR_200, NULL);
+  ExecCtx _local_exec_ctx;
+  grpc_mdelem el = grpc_mdelem_create(GRPC_MDSTR_STATUS, GRPC_MDSTR_200, NULL);
   while (state.KeepRunning()) {
-    GRPC_MDELEM_UNREF(&exec_ctx, GRPC_MDELEM_REF(el));
+    GRPC_MDELEM_UNREF(GRPC_MDELEM_REF(el));
   }
-  GRPC_MDELEM_UNREF(&exec_ctx, el);
-  grpc_exec_ctx_finish(&exec_ctx);
+  GRPC_MDELEM_UNREF(el);
+  grpc_exec_ctx_finish();
   track_counters.Finish(state);
 }
 BENCHMARK(BM_MetadataRefUnrefStatic);