--- old/src/hotspot/share/gc/shared/taskTerminator.hpp	2020-07-24 12:37:52.542761210 +0200
+++ new/src/hotspot/share/gc/shared/taskTerminator.hpp	2020-07-24 12:37:52.426759385 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
+ * Copyright (c) 2018, 2020, Red Hat, Inc. All rights reserved.
  * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -26,11 +26,12 @@
 #define SHARE_GC_SHARED_TASKTERMINATOR_HPP
 
 #include "memory/allocation.hpp"
+#include "memory/padded.hpp"
 #include "runtime/mutex.hpp"
-#include "runtime/thread.hpp"
 
 class TaskQueueSetSuper;
 class TerminatorTerminator;
+class Thread;
 
 /*
  * Provides a task termination protocol.
@@ -50,6 +51,16 @@
  * for stealing and termination condition.
  */
 class TaskTerminator : public CHeapObj<mtGC> {
+  struct DelayContext {
+    uint _yield_count;
+    // Number of hard spin loops done since last yield
+    uint _hard_spin_count;
+    // Number of iterations in the hard spin loop.
+    uint _hard_spin_limit;
+
+    DelayContext();
+  };
+
   uint _n_threads;
   TaskQueueSetSuper* _queue_set;
 
@@ -59,19 +70,21 @@
 
   void assert_queue_set_empty() const NOT_DEBUG_RETURN;
 
-  void yield();
+  Monitor _blocker;
+  Thread* _spin_master;
 
-  Monitor*    _blocker;
-  Thread*     _spin_master;
+  // Prepare for return from offer_termination. Gives up the spin master token
+  // and wakes up up to tasks threads waiting on _blocker (the default value
+  // means to wake up everyone).
+  void prepare_for_return(Thread* this_thread, size_t tasks = SIZE_MAX);
 
   // If we should exit current termination protocol
   bool exit_termination(size_t tasks, TerminatorTerminator* terminator);
 
   size_t tasks_in_queue_set() const;
 
-  // Perform spin-master task.
-  // Return true if termination condition is detected, otherwise return false
-  bool do_spin_master_work(TerminatorTerminator* terminator);
+  // Perform one iteration of spin-master work.
+  bool do_delay_step(DelayContext& delay_context);
 
   NONCOPYABLE(TaskTerminator);