1 /* 2 * Copyright (c) 2019, Red Hat, Inc. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 27 #include "runtime/os.hpp" 28 29 #include "gc/shenandoah/shenandoahLock.hpp" 30 #include "runtime/atomic.hpp" 31 #include "runtime/javaThread.hpp" 32 #include "runtime/os.inline.hpp" 33 34 ShenandoahSimpleLock::ShenandoahSimpleLock() { 35 assert(os::mutex_init_done(), "Too early!"); 36 } 37 38 void ShenandoahSimpleLock::lock() { 39 _lock.lock(); 40 } 41 42 void ShenandoahSimpleLock::unlock() { 43 _lock.unlock(); 44 } 45 46 ShenandoahReentrantLock::ShenandoahReentrantLock() : 47 ShenandoahSimpleLock(), _owner(nullptr), _count(0) { 48 assert(os::mutex_init_done(), "Too early!"); 49 } 50 51 ShenandoahReentrantLock::~ShenandoahReentrantLock() { 52 assert(_count == 0, "Unbalance"); 53 } 54 55 void ShenandoahReentrantLock::lock() { 56 Thread* const thread = Thread::current(); 57 Thread* const owner = Atomic::load(&_owner); 58 59 if (owner != thread) { 60 ShenandoahSimpleLock::lock(); 61 Atomic::store(&_owner, thread); 62 } 63 64 _count++; 65 } 66 67 void ShenandoahReentrantLock::unlock() { 68 assert(owned_by_self(), "Invalid owner"); 69 assert(_count > 0, "Invalid count"); 70 71 _count--; 72 73 if (_count == 0) { 74 Atomic::store(&_owner, (Thread*)nullptr); 75 ShenandoahSimpleLock::unlock(); 76 } 77 } 78 79 bool ShenandoahReentrantLock::owned_by_self() const { 80 Thread* const thread = Thread::current(); 81 Thread* const owner = Atomic::load(&_owner); 82 return owner == thread; 83 }