--- old/src/hotspot/share/gc/serial/serialHeap.hpp	2020-04-25 22:41:14.581515802 +0800
+++ new/src/hotspot/share/gc/serial/serialHeap.hpp	2020-04-25 22:41:14.421516514 +0800
@@ -75,6 +75,10 @@
   template <typename OopClosureType1, typename OopClosureType2>
   void oop_since_save_marks_iterate(OopClosureType1* cur,
                                     OopClosureType2* older);
+
+  // Runs the given AbstractGangTask with the current active workers, returning the
+  // total time taken.
+  virtual Tickspan run_task(AbstractGangTask* task);
 };
 
 #endif // SHARE_GC_SERIAL_SERIALHEAP_HPP