1 /* 2 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. 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 #include "gc_implementation/shared/suspendibleThreadSet.hpp" 27 #include "runtime/mutexLocker.hpp" 28 #include "runtime/thread.inline.hpp" 29 30 uint SuspendibleThreadSet::_nthreads = 0; 31 uint SuspendibleThreadSet::_nthreads_stopped = 0; 32 bool SuspendibleThreadSet::_suspend_all = false; 33 double SuspendibleThreadSet::_suspend_all_start = 0.0; 34 35 void SuspendibleThreadSet::join() { 36 assert(Thread::current()->is_suspendible_thread() == false, 37 "Thread already joined"); 38 MonitorLockerEx ml(STS_lock, Mutex::_no_safepoint_check_flag); 39 while (_suspend_all) { 40 ml.wait(Mutex::_no_safepoint_check_flag); 41 } 42 _nthreads++; 43 #ifdef ASSERT 44 Thread::current()->set_suspendible_thread(); 45 #endif 46 } 47 48 void SuspendibleThreadSet::leave() { 49 assert(Thread::current()->is_suspendible_thread(), 50 "Thread not joined"); 51 MonitorLockerEx ml(STS_lock, Mutex::_no_safepoint_check_flag); 52 assert(_nthreads > 0, "Invalid"); 53 #ifdef ASSERT 54 Thread::current()->clear_suspendible_thread(); 55 #endif 56 _nthreads--; 57 if (_suspend_all) { 58 ml.notify_all(); 59 } 60 } 61 62 void SuspendibleThreadSet::yield() { 63 assert(Thread::current()->is_suspendible_thread(), "Must have joined"); 64 if (_suspend_all) { 65 MonitorLockerEx ml(STS_lock, Mutex::_no_safepoint_check_flag); 66 if (_suspend_all) { 67 _nthreads_stopped++; 68 if (_nthreads_stopped == _nthreads) { 69 if (ConcGCYieldTimeout > 0) { 70 double now = os::elapsedTime(); 71 guarantee((now - _suspend_all_start) * 1000.0 < (double)ConcGCYieldTimeout, "Long delay"); 72 } 73 } 74 ml.notify_all(); 75 while (_suspend_all) { 76 ml.wait(Mutex::_no_safepoint_check_flag); 77 } 78 assert(_nthreads_stopped > 0, "Invalid"); 79 _nthreads_stopped--; 80 ml.notify_all(); 81 } 82 } 83 } 84 85 void SuspendibleThreadSet::synchronize() { 86 assert(Thread::current()->is_VM_thread(), "Must be the VM thread"); 87 if (ConcGCYieldTimeout > 0) { 88 _suspend_all_start = os::elapsedTime(); 89 } 90 MonitorLockerEx ml(STS_lock, Mutex::_no_safepoint_check_flag); 91 assert(!_suspend_all, "Only one at a time"); 92 _suspend_all = true; 93 while (_nthreads_stopped < _nthreads) { 94 ml.wait(Mutex::_no_safepoint_check_flag); 95 } 96 } 97 98 void SuspendibleThreadSet::desynchronize() { 99 assert(Thread::current()->is_VM_thread(), "Must be the VM thread"); 100 MonitorLockerEx ml(STS_lock, Mutex::_no_safepoint_check_flag); 101 assert(_nthreads_stopped == _nthreads, "Invalid"); 102 _suspend_all = false; 103 ml.notify_all(); 104 }