src/share/vm/gc/shared/threadLocalAllocBuffer.cpp

*** 1,7 ****
  /*
!  * Copyright (c) 1999, 2015, 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.
--- 1,7 ----
  /*
!  * Copyright (c) 1999, 2017, 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.
*** 40,49 ****
--- 40,51 ----
  unsigned         ThreadLocalAllocBuffer::_target_refills = 0;
  GlobalTLABStats* ThreadLocalAllocBuffer::_global_stats   = NULL;
  
  void ThreadLocalAllocBuffer::clear_before_allocation() {
    _slow_refill_waste += (unsigned)remaining();
+   assert(!ZapUnusedHeapArea || _reserve_for_allocation_prefetch > 0 || 
+     top() == NULL || *(intptr_t*)top() != 0, "overzeroing detected"); 
    make_parsable(true);   // also retire the TLAB
  }
  
  void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
    global_stats()->initialize();