--- old/src/hotspot/share/gc/z/zCollectedHeap.hpp	2020-04-25 22:41:18.029500446 +0800
+++ new/src/hotspot/share/gc/z/zCollectedHeap.hpp	2020-04-25 22:41:17.861501195 +0800
@@ -99,6 +99,10 @@
 
   virtual void object_iterate(ObjectClosure* cl);
 
+  // Runs the given AbstractGangTask with the current active workers, returning the
+  // total time taken.
+  virtual Tickspan run_task(AbstractGangTask* task);
+
   virtual void keep_alive(oop obj);
 
   virtual void register_nmethod(nmethod* nm);