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 "gc/g1/concurrentG1Refine.hpp" 27 #include "gc/g1/concurrentG1RefineThread.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.hpp" 29 #include "gc/g1/g1CollectorPolicy.hpp" 30 #include "gc/g1/suspendibleThreadSet.hpp" 31 #include "logging/log.hpp" 32 #include "memory/resourceArea.hpp" 33 #include "runtime/handles.inline.hpp" 34 #include "runtime/mutexLocker.hpp" 35 36 ConcurrentG1RefineThread:: 37 ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next, 38 CardTableEntryClosure* refine_closure, 39 uint worker_id_offset, uint worker_id) : 40 ConcurrentGCThread(), 41 _refine_closure(refine_closure), 42 _worker_id_offset(worker_id_offset), 43 _worker_id(worker_id), 44 _active(false), 45 _next(next), 46 _monitor(NULL), 47 _cg1r(cg1r), 48 _vtime_accum(0.0) 49 { 50 51 // Each thread has its own monitor. The i-th thread is responsible for signaling 52 // to thread i+1 if the number of buffers in the queue exceeds a threshold for this 53 // thread. Monitors are also used to wake up the threads during termination. 54 // The 0th (primary) worker is notified by mutator threads and has a special monitor. 55 if (!is_primary()) { 56 _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true, 57 Monitor::_safepoint_check_never); 58 } else { 59 _monitor = DirtyCardQ_CBL_mon; 60 } 61 initialize(); 62 63 // set name 64 set_name("G1 Refine#%d", worker_id); 65 create_and_start(); 66 } 67 68 void ConcurrentG1RefineThread::initialize() { 69 // Current thread activation threshold 70 _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(), 71 cg1r()->yellow_zone()); 72 // A thread deactivates once the number of buffer reached a deactivation threshold 73 _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone()); 74 } 75 76 void ConcurrentG1RefineThread::wait_for_completed_buffers() { 77 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 78 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 79 while (!_should_terminate && !is_active()) { 80 _monitor->wait(Mutex::_no_safepoint_check_flag); 81 } 82 } 83 84 bool ConcurrentG1RefineThread::is_active() { 85 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 86 return is_primary() ? dcqs.process_completed_buffers() : _active; 87 } 88 89 void ConcurrentG1RefineThread::activate() { 90 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 91 if (!is_primary()) { 92 log_debug(gc, refine)("G1-Refine-activated worker %d, on threshold %d, current %d", 93 _worker_id, _threshold, JavaThread::dirty_card_queue_set().completed_buffers_num()); 94 set_active(true); 95 } else { 96 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 97 dcqs.set_process_completed(true); 98 } 99 _monitor->notify(); 100 } 101 102 void ConcurrentG1RefineThread::deactivate() { 103 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 104 if (!is_primary()) { 105 log_debug(gc, refine)("G1-Refine-deactivated worker %d, off threshold %d, current %d", 106 _worker_id, _deactivation_threshold, JavaThread::dirty_card_queue_set().completed_buffers_num()); 107 set_active(false); 108 } else { 109 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 110 dcqs.set_process_completed(false); 111 } 112 } 113 114 void ConcurrentG1RefineThread::run() { 115 initialize_in_thread(); 116 wait_for_universe_init(); 117 118 run_service(); 119 120 terminate(); 121 } 122 123 void ConcurrentG1RefineThread::run_service() { 124 _vtime_start = os::elapsedVTime(); 125 126 while (!_should_terminate) { 127 // Wait for work 128 wait_for_completed_buffers(); 129 if (_should_terminate) { 130 break; 131 } 132 133 { 134 SuspendibleThreadSetJoiner sts_join; 135 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 136 137 do { 138 int curr_buffer_num = (int)dcqs.completed_buffers_num(); 139 // If the number of the buffers falls down into the yellow zone, 140 // that means that the transition period after the evacuation pause has ended. 141 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) { 142 dcqs.set_completed_queue_padding(0); 143 } 144 145 if (!is_primary() && curr_buffer_num <= _deactivation_threshold) { 146 // If the number of the buffer has fallen below our threshold 147 // we should deactivate. The predecessor will reactivate this 148 // thread should the number of the buffers cross the threshold again. 149 deactivate(); 150 break; 151 } 152 153 // Check if we need to activate the next thread. 154 if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) { 155 _next->activate(); 156 } 157 } while (dcqs.apply_closure_to_completed_buffer(_refine_closure, 158 _worker_id + _worker_id_offset, 159 cg1r()->green_zone(), 160 false /* during_pause */)); 161 162 // We can exit the loop above while being active if there was a yield request. 163 if (is_active()) { 164 deactivate(); 165 } 166 } 167 168 if (os::supports_vtime()) { 169 _vtime_accum = (os::elapsedVTime() - _vtime_start); 170 } else { 171 _vtime_accum = 0.0; 172 } 173 } 174 175 log_debug(gc, refine)("G1-Refine-stop"); 176 } 177 178 void ConcurrentG1RefineThread::stop() { 179 // it is ok to take late safepoints here, if needed 180 { 181 MutexLockerEx mu(Terminator_lock); 182 _should_terminate = true; 183 } 184 185 stop_service(); 186 187 { 188 MutexLockerEx mu(Terminator_lock); 189 while (!_has_terminated) { 190 Terminator_lock->wait(); 191 } 192 } 193 } 194 195 void ConcurrentG1RefineThread::stop_service() { 196 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 197 _monitor->notify(); 198 }