diff -r d7c83c8e4e65 -r bfc70d5d291a src/hotspot/share/runtime/mutexLocker.cpp
--- a/src/hotspot/share/runtime/mutexLocker.cpp	Tue Mar 20 15:38:00 2018 +0100
+++ b/src/hotspot/share/runtime/mutexLocker.cpp	Mon Mar 26 09:35:20 2018 -0400
@@ -138,6 +138,8 @@
 Mutex*   UnsafeJlong_lock             = NULL;
 #endif
 
+Mutex*   MetaspaceExpand_lock         = NULL;
+
 #define MAX_NUM_MUTEX 128
 static Monitor * _mutex_array[MAX_NUM_MUTEX];
 static int _num_mutex;
@@ -210,6 +212,8 @@
   def(RawMonitor_lock              , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);
   def(OopMapCacheAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for oop_map_cache allocation.
 
+  def(MetaspaceExpand_lock         , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);
+
   def(Patching_lock                , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);      // used for safepointing and code patching.
   def(Service_lock                 , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // used for service thread operations
   def(JmethodIdCreation_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);     // used for creating jmethodIDs.