8230845: ZGC: Implement ZLock using os::PlatformMutex

Reviewed-by: stefank

Author: pliden

src/hotspot/share/gc/z/zLock.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2019, 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
@@ -25,16 +25,13 @@
 #define SHARE_GC_Z_ZLOCK_HPP
 
 #include "memory/allocation.hpp"
-#include <pthread.h>
+#include "runtime/os.hpp"
 
 class ZLock {
 private:
-  pthread_mutex_t _lock;
+  os::PlatformMutex _lock;
 
 public:
-  ZLock();
-  ~ZLock();
-
   void lock();
   bool try_lock();
   void unlock();

src/hotspot/share/gc/z/zLock.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2019, 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
@@ -26,27 +26,20 @@
 
 #include "gc/z/zLock.hpp"
 #include "runtime/atomic.hpp"
+#include "runtime/os.inline.hpp"
 #include "runtime/thread.hpp"
 #include "utilities/debug.hpp"
 
-inline ZLock::ZLock() {
-  pthread_mutex_init(&_lock, NULL);
-}
-
-inline ZLock::~ZLock() {
-  pthread_mutex_destroy(&_lock);
-}
-
 inline void ZLock::lock() {
-  pthread_mutex_lock(&_lock);
+  _lock.lock();
 }
 
 inline bool ZLock::try_lock() {
-  return pthread_mutex_trylock(&_lock) == 0;
+  return _lock.try_lock();
 }
 
 inline void ZLock::unlock() {
-  pthread_mutex_unlock(&_lock);
+  _lock.unlock();
 }
 
 inline ZReentrantLock::ZReentrantLock() :