src/hotspot/share/gc/g1/g1VMOperations.cpp

rev 57464 : [mq]: fix

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -45,10 +45,11 @@
                                                    double target_pause_time_ms) :
   VM_GC_Operation(gc_count_before, gc_cause),
   _target_pause_time_ms(target_pause_time_ms),
   _transient_failure(false),
   _cycle_already_in_progress(false),
+  _terminating(false),
   _gc_succeeded(false)
 {}
 
 bool VM_G1TryInitiateConcMark::doit_prologue() {
   bool result = VM_GC_Operation::doit_prologue();

@@ -64,11 +65,21 @@
 
 void VM_G1TryInitiateConcMark::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 
   GCCauseSetter x(g1h, _gc_cause);
-  if (!g1h->policy()->force_initial_mark_if_outside_cycle(_gc_cause)) {
+
+  // Record for handling by caller.
+  _terminating = g1h->_cm_thread->should_terminate();
+
+  if (_terminating && GCCause::is_user_requested_gc(_gc_cause)) {
+    // When terminating, the request to initiate a concurrent cycle will be
+    // ignored by do_collection_pause_at_safepoint; instead it will just do
+    // a young-only or mixed GC (depending on phase).  For a user request
+    // there's no point in even doing that much, so done.  For some non-user
+    // requests the alternative GC might still be needed.
+  } else if (!g1h->policy()->force_initial_mark_if_outside_cycle(_gc_cause)) {
     // Failure to force the next GC pause to be an initial mark indicates
     // there is already a concurrent marking cycle in progress.  Set flag
     // to notify the caller and return immediately.
     _cycle_already_in_progress = true;
   } else if (!g1h->do_collection_pause_at_safepoint(_target_pause_time_ms)) {