| /* |
| * Copyright (c) 2014, 2018, 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. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_JFR_UTILITIES_JFRTRYLOCK_HPP |
| #define SHARE_VM_JFR_UTILITIES_JFRTRYLOCK_HPP |
| |
| #include "runtime/atomic.hpp" |
| #include "runtime/orderAccess.hpp" |
| #include "runtime/mutexLocker.hpp" |
| #include "utilities/debug.hpp" |
| |
| class JfrTryLock { |
| private: |
| volatile int* const _lock; |
| bool _has_lock; |
| |
| public: |
| JfrTryLock(volatile int* lock) : _lock(lock), _has_lock(Atomic::cmpxchg(1, lock, 0) == 0) {} |
| |
| ~JfrTryLock() { |
| if (_has_lock) { |
| OrderAccess::fence(); |
| *_lock = 0; |
| } |
| } |
| |
| bool has_lock() const { |
| return _has_lock; |
| } |
| }; |
| |
| class JfrMonitorTryLock : public StackObj { |
| private: |
| Monitor* _lock; |
| bool _acquired; |
| |
| public: |
| JfrMonitorTryLock(Monitor* lock) : _lock(lock), _acquired(lock->try_lock()) {} |
| |
| ~JfrMonitorTryLock() { |
| if (_acquired) { |
| assert(_lock->owned_by_self(), "invariant"); |
| _lock->unlock(); |
| } |
| } |
| |
| bool acquired() const { |
| return _acquired; |
| } |
| |
| }; |
| |
| #endif // SHARE_VM_JFR_UTILITIES_JFRTRYLOCK_HPP |