Fast-pathed grpc_mdelem_eq for known static cases.

src/core/ext/filters/http/client/http_client_filter.cc

@@ -107,7 +107,8 @@ static grpc_error* client_filter_incoming_metadata(grpc_call_element* elem,
      * https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md.
      */
     if (b->idx.named.grpc_status != nullptr ||
-        grpc_mdelem_eq(b->idx.named.status->md, GRPC_MDELEM_STATUS_200)) {
+        grpc_mdelem_eq_static(b->idx.named.status->md,
+                              GRPC_MDELEM_STATUS_200)) {
       grpc_metadata_batch_remove(b, b->idx.named.status);
     } else {
       char* val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.status->md),
@@ -140,8 +141,9 @@ static grpc_error* client_filter_incoming_metadata(grpc_call_element* elem,
   }
 
   if (b->idx.named.content_type != nullptr) {
-    if (!grpc_mdelem_eq(b->idx.named.content_type->md,
-                        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
+    if (!grpc_mdelem_eq_static(
+            b->idx.named.content_type->md,
+            GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
       if (grpc_slice_buf_start_eq(GRPC_MDVALUE(b->idx.named.content_type->md),
                                   EXPECTED_CONTENT_TYPE,
                                   EXPECTED_CONTENT_TYPE_LENGTH) &&

src/core/ext/filters/http/server/http_server_filter.cc

@@ -131,22 +131,23 @@ static grpc_error* hs_filter_incoming_metadata(grpc_call_element* elem,
   static const char* error_name = "Failed processing incoming headers";
 
   if (b->idx.named.method != nullptr) {
-    if (grpc_mdelem_eq(b->idx.named.method->md, GRPC_MDELEM_METHOD_POST)) {
+    if (grpc_mdelem_eq_static(b->idx.named.method->md,
+                              GRPC_MDELEM_METHOD_GET)) {
+      *calld->recv_initial_metadata_flags |=
+          GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
+      *calld->recv_initial_metadata_flags &=
+          ~GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
+    } else if (grpc_mdelem_eq_static(b->idx.named.method->md,
+                                     GRPC_MDELEM_METHOD_POST)) {
       *calld->recv_initial_metadata_flags &=
           ~(GRPC_INITIAL_METADATA_CACHEABLE_REQUEST |
             GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST);
-    } else if (grpc_mdelem_eq(b->idx.named.method->md,
-                              GRPC_MDELEM_METHOD_PUT)) {
+    } else if (grpc_mdelem_eq_static(b->idx.named.method->md,
+                                     GRPC_MDELEM_METHOD_PUT)) {
       *calld->recv_initial_metadata_flags &=
           ~GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
       *calld->recv_initial_metadata_flags |=
           GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
-    } else if (grpc_mdelem_eq(b->idx.named.method->md,
-                              GRPC_MDELEM_METHOD_GET)) {
-      *calld->recv_initial_metadata_flags |=
-          GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
-      *calld->recv_initial_metadata_flags &=
-          ~GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
     } else {
       hs_add_error(error_name, &error,
                    grpc_attach_md_to_error(
@@ -163,7 +164,7 @@ static grpc_error* hs_filter_incoming_metadata(grpc_call_element* elem,
   }
 
   if (b->idx.named.te != nullptr) {
-    if (!grpc_mdelem_eq(b->idx.named.te->md, GRPC_MDELEM_TE_TRAILERS)) {
+    if (!grpc_mdelem_eq_static(b->idx.named.te->md, GRPC_MDELEM_TE_TRAILERS)) {
       hs_add_error(error_name, &error,
                    grpc_attach_md_to_error(
                        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
@@ -178,9 +179,12 @@ static grpc_error* hs_filter_incoming_metadata(grpc_call_element* elem,
   }
 
   if (b->idx.named.scheme != nullptr) {
-    if (!grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTP) &&
-        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTPS) &&
-        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_GRPC)) {
+    if (!grpc_mdelem_eq_static(b->idx.named.scheme->md,
+                               GRPC_MDELEM_SCHEME_HTTP) &&
+        !grpc_mdelem_eq_static(b->idx.named.scheme->md,
+                               GRPC_MDELEM_SCHEME_HTTPS) &&
+        !grpc_mdelem_eq_static(b->idx.named.scheme->md,
+                               GRPC_MDELEM_SCHEME_GRPC)) {
       hs_add_error(error_name, &error,
                    grpc_attach_md_to_error(
                        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
@@ -196,8 +200,9 @@ static grpc_error* hs_filter_incoming_metadata(grpc_call_element* elem,
   }
 
   if (b->idx.named.content_type != nullptr) {
-    if (!grpc_mdelem_eq(b->idx.named.content_type->md,
-                        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
+    if (!grpc_mdelem_eq_static(
+            b->idx.named.content_type->md,
+            GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
       if (grpc_slice_buf_start_eq(GRPC_MDVALUE(b->idx.named.content_type->md),
                                   EXPECTED_CONTENT_TYPE,
                                   EXPECTED_CONTENT_TYPE_LENGTH) &&

src/core/ext/transport/chttp2/transport/chttp2_transport.cc

@@ -1281,8 +1281,8 @@ void grpc_chttp2_complete_closure_step(grpc_chttp2_transport* t,
 
 static bool contains_non_ok_status(grpc_metadata_batch* batch) {
   if (batch->idx.named.grpc_status != nullptr) {
-    return !grpc_mdelem_eq(batch->idx.named.grpc_status->md,
-                           GRPC_MDELEM_GRPC_STATUS_0);
+    return !grpc_mdelem_eq_static(batch->idx.named.grpc_status->md,
+                                  GRPC_MDELEM_GRPC_STATUS_0);
   }
   return false;
 }

src/core/lib/transport/metadata.h

@@ -126,6 +126,10 @@ grpc_mdelem grpc_mdelem_create(
 
 bool grpc_mdelem_eq(grpc_mdelem a, grpc_mdelem b);
 
+inline bool grpc_mdelem_eq_static(grpc_mdelem a_static, grpc_mdelem b_static) {
+  return a_static.payload == b_static.payload;
+}
+
 /* Mutator and accessor for grpc_mdelem user data. The destructor function
    is used as a type tag and is checked during user_data fetch. */
 void* grpc_mdelem_get_user_data(grpc_mdelem md, void (*if_destroy_func)(void*));

src/core/lib/transport/status_metadata.cc

@@ -31,13 +31,13 @@
 static void destroy_status(void* ignored) {}
 
 grpc_status_code grpc_get_status_code_from_metadata(grpc_mdelem md) {
-  if (grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
+  if (grpc_mdelem_eq_static(md, GRPC_MDELEM_GRPC_STATUS_0)) {
     return GRPC_STATUS_OK;
   }
-  if (grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_1)) {
+  if (grpc_mdelem_eq_static(md, GRPC_MDELEM_GRPC_STATUS_1)) {
     return GRPC_STATUS_CANCELLED;
   }
-  if (grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_2)) {
+  if (grpc_mdelem_eq_static(md, GRPC_MDELEM_GRPC_STATUS_2)) {
     return GRPC_STATUS_UNKNOWN;
   }
   void* user_data = grpc_mdelem_get_user_data(md, destroy_status);