[GitHub] [incubator-brpc] chenBright commented on a diff in pull request #1817: fix additional refrerence can not release when socket is reviving

[GitBox <gi...@apache.org>]

chenBright commented on code in PR #1817:
URL: https://github.com/apache/incubator-brpc/pull/1817#discussion_r928100985


##########
src/brpc/socket.cpp:
##########
@@ -770,15 +773,22 @@ void Socket::Revive() {
 }
 
 int Socket::ReleaseAdditionalReference() {
-    bool expect = false;
-    // Use `relaxed' fence here since `Dereference' has `released' fence
-    if (_recycle_flag.compare_exchange_strong(
-            expect, true,
+    do {
+        AdditionalRefStatus expect = REF_USING;
+        if (_additional_ref_status.compare_exchange_strong(
+            expect,
+            REF_RECYLED,
             butil::memory_order_relaxed,
             butil::memory_order_relaxed)) {
-        return Dereference();
-    }
-    return -1;
+            return Dereference();
+        }
+
+        if (expect == REF_REVIVING) { // sched_yield to wait until status is not REF_REVIVING
+            sched_yield();

Review Comment:
   当时考虑这个情况很低频，并且_additional_ref_status很快就能从REF_REVIVING变成REF_USING，即使sched_yield do nothing[1]了，应该也不会忙等太久，所以就没考虑wait/wake的实现方案。



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