--- old/src/hotspot/share/gc/z/zMemory.hpp	2020-05-18 23:08:31.959742593 +0200
+++ new/src/hotspot/share/gc/z/zMemory.hpp	2020-05-18 23:08:31.701734224 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 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
@@ -25,6 +25,7 @@
 #define SHARE_GC_Z_ZMEMORY_HPP
 
 #include "gc/z/zList.hpp"
+#include "gc/z/zLock.hpp"
 #include "memory/allocation.hpp"
 
 class ZMemory : public CHeapObj<mtGC> {
@@ -65,6 +66,7 @@
   };
 
 private:
+  ZLock          _lock;
   ZList<ZMemory> _freelist;
   Callbacks      _callbacks;