1 /* 2 * Copyright (c) 2001, 2016, 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 "classfile/systemDictionary.hpp" 27 #include "gc/shared/concurrentGCThread.hpp" 28 #include "oops/instanceRefKlass.hpp" 29 #include "oops/oop.inline.hpp" 30 #include "runtime/init.hpp" 31 #include "runtime/java.hpp" 32 #include "runtime/javaCalls.hpp" 33 #include "runtime/os.hpp" 34 35 ConcurrentGCThread::ConcurrentGCThread() : 36 _should_terminate(false), _has_terminated(false) { 37 }; 38 39 void ConcurrentGCThread::create_and_start(ThreadPriority prio) { 40 if (os::create_thread(this, os::cgc_thread)) { 41 // XXX: need to set this to low priority 42 // unless "aggressive mode" set; priority 43 // should be just less than that of VMThread. 44 os::set_priority(this, prio); 45 if (!_should_terminate) { 46 os::start_thread(this); 47 } 48 } 49 } 50 51 void ConcurrentGCThread::initialize_in_thread() { 52 this->set_active_handles(JNIHandleBlock::allocate_block()); 53 // From this time Thread::current() should be working. 54 assert(this == Thread::current(), "just checking"); 55 } 56 57 void ConcurrentGCThread::wait_for_universe_init() { 58 MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag); 59 while (!is_init_completed() && !_should_terminate) { 60 CGC_lock->wait(Mutex::_no_safepoint_check_flag, 1); 61 } 62 } 63 64 void ConcurrentGCThread::terminate() { 65 assert(_should_terminate, "Should only be called on terminate request."); 66 // Signal that it is terminated 67 { 68 MutexLockerEx mu(Terminator_lock, 69 Mutex::_no_safepoint_check_flag); 70 _has_terminated = true; 71 Terminator_lock->notify(); 72 } 73 } 74 75 void ConcurrentGCThread::run() { 76 initialize_in_thread(); 77 wait_for_universe_init(); 78 79 run_service(); 80 81 terminate(); 82 } 83 84 void ConcurrentGCThread::stop() { 85 // it is ok to take late safepoints here, if needed 86 { 87 MutexLockerEx mu(Terminator_lock); 88 assert(!_has_terminated, "stop should only be called once"); 89 assert(!_should_terminate, "stop should only be called once"); 90 _should_terminate = true; 91 } 92 93 stop_service(); 94 95 { 96 MutexLockerEx mu(Terminator_lock); 97 while (!_has_terminated) { 98 Terminator_lock->wait(); 99 } 100 } 101 }