tc_contention_warning_reported transition to std::atomic

sql/table_cache.cc

@@ -57,7 +57,7 @@ ulong tdc_size; /**< Table definition cache threshold for LRU eviction. */
 ulong tc_size; /**< Table cache threshold for LRU eviction. */
 uint32 tc_instances;
 uint32 tc_active_instances= 1;
-static uint32 tc_contention_warning_reported;
+static std::atomic<bool> tc_contention_warning_reported;
 
 /** Data collections. */
 static LF_HASH tdc_hash; /**< Collection of TABLE_SHARE objects. */
@@ -187,8 +187,8 @@ struct Table_cache_instance
                                   n_instances + 1);
           }
         }
-        else if (!my_atomic_fas32_explicit((int32*) &tc_contention_warning_reported,
-                                           1, MY_MEMORY_ORDER_RELAXED))
+        else if (!tc_contention_warning_reported.exchange(true,
+                                                 std::memory_order_relaxed))
         {
           sql_print_warning("Detected table cache mutex contention at instance %d: "
                             "%d%% waits. Additional table cache instance "