--- old/src/hotspot/share/runtime/mutexLocker.cpp	2017-10-06 14:50:49.614510684 -0700
+++ new/src/hotspot/share/runtime/mutexLocker.cpp	2017-10-06 14:50:49.242511936 -0700
@@ -125,6 +125,8 @@
 Monitor* PeriodicTask_lock            = NULL;
 Monitor* RedefineClasses_lock         = NULL;
 
+Monitor* HeapMonitor_lock             = NULL;
+
 #if INCLUDE_TRACE
 Mutex*   JfrStacktrace_lock           = NULL;
 Monitor* JfrMsg_lock                  = NULL;
@@ -275,6 +277,9 @@
   def(CompileThread_lock           , PaddedMonitor, nonleaf+5,   false, Monitor::_safepoint_check_always);
   def(PeriodicTask_lock            , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_sometimes);
   def(RedefineClasses_lock         , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);
+
+  def(HeapMonitor_lock             , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);
+
   if (WhiteBoxAPI) {
     def(Compilation_lock           , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_never);
   }