diff -r c97db0855565 -r 758c07667682 src/share/vm/memory/gcLocker.hpp
--- a/src/share/vm/memory/gcLocker.hpp	Tue Feb 04 17:38:01 2020 +0800
+++ b/src/share/vm/memory/gcLocker.hpp	Tue Feb 04 18:13:14 2020 +0800
@@ -26,6 +26,7 @@
 #define SHARE_VM_MEMORY_GCLOCKER_HPP
 
 #include "gc_interface/collectedHeap.hpp"
+#include "gc_interface/gcCause.hpp"
 #include "memory/genCollectedHeap.hpp"
 #include "memory/universe.hpp"
 #include "oops/oop.hpp"
@@ -57,6 +58,7 @@
   static volatile bool _needs_gc;        // heap is filling, we need a GC
                                          // note: bool is typedef'd as jint
   static volatile bool _doing_gc;        // unlock_critical() is doing a GC
+  static uint _total_collections;        // value for _gc_locker collection
 
 #ifdef ASSERT
   // This lock count is updated for all operations and is used to
@@ -116,6 +118,12 @@
   // Sets _needs_gc if is_active() is true. Returns is_active().
   static bool check_active_before_gc();
 
+  // Return true if the designated collection is a GCLocker request
+  // that should be discarded.  Returns true if cause == GCCause::_gc_locker
+  // and the given total collection value indicates a collection has been
+  // done since the GCLocker request was made.
+  static bool should_discard(GCCause::Cause cause, uint total_collections);
+
   // Stalls the caller (who should not be in a jni critical section)
   // until needs_gc() clears. Note however that needs_gc() may be
   // set at a subsequent safepoint and/or cleared under the