Update block_annotate.h

src/core/lib/support/block_annotate.h

@@ -19,15 +19,37 @@
 #ifndef GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H
 #define GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void gpr_thd_start_blocking_region();
+void gpr_thd_end_blocking_region();
+
+#ifdef __cplusplus
+}
+#endif
+
 /* These annotations identify the beginning and end of regions where
    the code may block for reasons other than synchronization functions.
    These include poll, epoll, and getaddrinfo. */
 
+#ifdef GRPC_SCHEDULING_MARK_BLOCKING_REGION
+#define GRPC_SCHEDULING_START_BLOCKING_REGION \
+  do {                                        \
+    gpr_thd_start_blocking_region();          \
+  } while (0)
+#define GRPC_SCHEDULING_END_BLOCKING_REGION \
+  do {                                      \
+    gpr_thd_end_blocking_region();          \
+  } while (0)
+#else
 #define GRPC_SCHEDULING_START_BLOCKING_REGION \
   do {                                        \
   } while (0)
 #define GRPC_SCHEDULING_END_BLOCKING_REGION \
   do {                                      \
   } while (0)
+#endif
 
 #endif /* GRPC_CORE_LIB_SUPPORT_BLOCK_ANNOTATE_H */