--- old/src/hotspot/share/gc/z/zHeap.hpp	2020-04-25 20:53:36.995323647 +0800
+++ new/src/hotspot/share/gc/z/zHeap.hpp	2020-04-25 20:53:36.823324172 +0800
@@ -105,6 +105,10 @@
   void set_boost_worker_threads(bool boost);
   void worker_threads_do(ThreadClosure* tc) const;
   void print_worker_threads_on(outputStream* st) const;
+  // Runs the given AbstractGangTask with the current active workers, returning the
+  // total time taken.
+  Tickspan run_task(AbstractGangTask* task);
+
 
   // Reference processing
   ReferenceDiscoverer* reference_discoverer();