--- old/src/hotspot/share/runtime/mutexLocker.hpp	2020-01-16 01:05:24.496678130 -0500
+++ new/src/hotspot/share/runtime/mutexLocker.hpp	2020-01-16 01:05:24.112657399 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -69,8 +69,6 @@
 extern Monitor* STS_lock;                        // used for joining/leaving SuspendibleThreadSet.
 extern Monitor* FullGCCount_lock;                // in support of "concurrent" full gc
 extern Monitor* G1OldGCCount_lock;               // in support of "concurrent" full gc
-extern Monitor* DirtyCardQ_CBL_mon;              // Protects dirty card Q
-                                                 // completed buffer queue.
 extern Mutex*   Shared_DirtyCardQ_lock;          // Lock protecting dirty card
                                                  // queue shared by
                                                  // non-Java threads.