--- a/src/hotspot/share/runtime/thread.cpp	Mon Apr 29 14:34:10 2019 -0400
+++ b/src/hotspot/share/runtime/thread.cpp	Mon Apr 29 16:01:52 2019 -0400
@@ -794,14 +794,12 @@
     // safepoint requests from the VMThread
 
     {
-      MutexLocker ml(SR_lock());
+      Thread* t = Thread::current();
+      MonitorLocker ml(SR_lock(),
+                       t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag);
       // wait with safepoint check (if we're a JavaThread - the WatcherThread
       // can also call this)  and increase delay with each retry
-      if (Thread::current()->is_Java_thread()) {
-        SR_lock()->wait(i * delay);
-      } else {
-        SR_lock()->wait_without_safepoint_check(i * delay);
-      }
+      ml.wait(i * delay);
 
       is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
                                               delay, bits);
@@ -1405,7 +1403,7 @@
 int WatcherThread::sleep() const {
   // The WatcherThread does not participate in the safepoint protocol
   // for the PeriodicTask_lock because it is not a JavaThread.
-  MutexLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
+  MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
 
   if (_should_terminate) {
     // check for termination before we do any housekeeping or wait
@@ -1425,7 +1423,7 @@
   jlong time_before_loop = os::javaTimeNanos();
 
   while (true) {
-    bool timedout = PeriodicTask_lock->wait_without_safepoint_check(remaining);
+    bool timedout = ml.wait(remaining);
     jlong now = os::javaTimeNanos();
 
     if (remaining == 0) {
@@ -1548,12 +1546,12 @@
     }
   }
 
-  MutexLocker mu(Terminator_lock);
+  MonitorLocker mu(Terminator_lock);
 
   while (watcher_thread() != NULL) {
     // This wait should make safepoint checks, wait without a timeout,
     // and wait as a suspend-equivalent condition.
-    Terminator_lock->wait(0, Mutex::_as_suspend_equivalent_flag);
+    mu.wait(0, Mutex::_as_suspend_equivalent_flag);
   }
 }
 
@@ -2424,7 +2422,7 @@
          (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
          "must have walkable stack");
 
-  MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+  MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
 
   assert(!this->is_ext_suspended(),
          "a thread trying to self-suspend should not already be suspended");
@@ -2452,7 +2450,7 @@
 
     // _ext_suspended flag is cleared by java_resume()
     while (is_ext_suspended()) {
-      this->SR_lock()->wait_without_safepoint_check();
+      ml.wait();
     }
   }
   return ret;
@@ -3844,10 +3842,10 @@
     // Wait for the VM thread to become ready, and VMThread::run to initialize
     // Monitors can have spurious returns, must always check another state flag
     {
-      MutexLocker ml(Notify_lock);
+      MonitorLocker ml(Notify_lock);
       os::start_thread(vmthread);
       while (vmthread->active_handles() == NULL) {
-        Notify_lock->wait();
+        ml.wait();
       }
     }
   }
@@ -4325,11 +4323,11 @@
   _vm_complete = false;
 #endif
   // Wait until we are the last non-daemon thread to execute
-  { MutexLocker nu(Threads_lock);
+  { MonitorLocker nu(Threads_lock);
     while (Threads::number_of_non_daemon_threads() > 1)
       // This wait should make safepoint checks, wait without a timeout,
       // and wait as a suspend-equivalent condition.
-      Threads_lock->wait(0, Mutex::_as_suspend_equivalent_flag);
+      nu.wait(0, Mutex::_as_suspend_equivalent_flag);
   }
 
   EventShutdown e;
@@ -4465,7 +4463,7 @@
 
   // Extra scope needed for Thread_lock, so we can check
   // that we do not remove thread without safepoint code notice
-  { MutexLocker ml(Threads_lock);
+  { MonitorLocker ml(Threads_lock);
 
     assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
 
@@ -4493,7 +4491,7 @@
       // Only one thread left, do a notify on the Threads_lock so a thread waiting
       // on destroy_vm will wake up.
       if (number_of_non_daemon_threads() == 1) {
-        Threads_lock->notify_all();
+        ml.notify_all();
       }
     }
     ThreadService::remove_thread(p, is_daemon);