1 /* 2 * Copyright (c) 2001, 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/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 "memory/resourceArea.hpp" 32 #include "runtime/handles.inline.hpp" 33 #include "runtime/mutexLocker.hpp" 34 35 ConcurrentG1RefineThread:: 36 ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next, 37 CardTableEntryClosure* refine_closure, 38 uint worker_id_offset, uint worker_id) : 39 ConcurrentGCThread(), 40 _refine_closure(refine_closure), 41 _worker_id_offset(worker_id_offset), 42 _worker_id(worker_id), 43 _active(false), 44 _next(next), 45 _monitor(NULL), 46 _cg1r(cg1r), 47 _vtime_accum(0.0) 48 { 49 50 // Each thread has its own monitor. The i-th thread is responsible for signaling 51 // to thread i+1 if the number of buffers in the queue exceeds a threshold for this 52 // thread. Monitors are also used to wake up the threads during termination. 53 // The 0th (primary) worker is notified by mutator threads and has a special monitor. 54 if (!is_primary()) { 55 _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true, 56 Monitor::_safepoint_check_never); 57 } else { 58 _monitor = DirtyCardQ_CBL_mon; 59 } 60 initialize(); 61 create_and_start(); 62 63 // set name 64 set_name("G1 Refine#%d", worker_id); 65 } 66 67 void ConcurrentG1RefineThread::initialize() { 68 // Current thread activation threshold 69 _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(), 70 cg1r()->yellow_zone()); 71 // A thread deactivates once the number of buffer reached a deactivation threshold 72 _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone()); 73 } 74 75 void ConcurrentG1RefineThread::wait_for_completed_buffers() { 76 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 77 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 78 while (!_should_terminate && !is_active()) { 79 _monitor->wait(Mutex::_no_safepoint_check_flag); 80 } 81 } 82 83 bool ConcurrentG1RefineThread::is_active() { 84 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 85 return is_primary() ? dcqs.process_completed_buffers() : _active; 86 } 87 88 void ConcurrentG1RefineThread::activate() { 89 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 90 if (!is_primary()) { 91 if (G1TraceConcRefinement) { 92 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 93 gclog_or_tty->print_cr("G1-Refine-activated worker %d, on threshold %d, current %d", 94 _worker_id, _threshold, (int)dcqs.completed_buffers_num()); 95 } 96 set_active(true); 97 } else { 98 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 99 dcqs.set_process_completed(true); 100 } 101 _monitor->notify(); 102 } 103 104 void ConcurrentG1RefineThread::deactivate() { 105 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 106 if (!is_primary()) { 107 if (G1TraceConcRefinement) { 108 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 109 gclog_or_tty->print_cr("G1-Refine-deactivated worker %d, off threshold %d, current %d", 110 _worker_id, _deactivation_threshold, (int)dcqs.completed_buffers_num()); 111 } 112 set_active(false); 113 } else { 114 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 115 dcqs.set_process_completed(false); 116 } 117 } 118 119 void ConcurrentG1RefineThread::run() { 120 initialize_in_thread(); 121 wait_for_universe_init(); 122 123 run_service(); 124 125 terminate(); 126 } 127 128 void ConcurrentG1RefineThread::run_service() { 129 _vtime_start = os::elapsedVTime(); 130 131 while (!_should_terminate) { 132 // Wait for work 133 wait_for_completed_buffers(); 134 if (_should_terminate) { 135 break; 136 } 137 138 { 139 SuspendibleThreadSetJoiner sts_join; 140 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 141 142 do { 143 int curr_buffer_num = (int)dcqs.completed_buffers_num(); 144 // If the number of the buffers falls down into the yellow zone, 145 // that means that the transition period after the evacuation pause has ended. 146 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) { 147 dcqs.set_completed_queue_padding(0); 148 } 149 150 if (!is_primary() && curr_buffer_num <= _deactivation_threshold) { 151 // If the number of the buffer has fallen below our threshold 152 // we should deactivate. The predecessor will reactivate this 153 // thread should the number of the buffers cross the threshold again. 154 deactivate(); 155 break; 156 } 157 158 // Check if we need to activate the next thread. 159 if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) { 160 _next->activate(); 161 } 162 } while (dcqs.apply_closure_to_completed_buffer(_refine_closure, _worker_id + _worker_id_offset, cg1r()->green_zone())); 163 164 // We can exit the loop above while being active if there was a yield request. 165 if (is_active()) { 166 deactivate(); 167 } 168 } 169 170 if (os::supports_vtime()) { 171 _vtime_accum = (os::elapsedVTime() - _vtime_start); 172 } else { 173 _vtime_accum = 0.0; 174 } 175 } 176 177 if (G1TraceConcRefinement) { 178 gclog_or_tty->print_cr("G1-Refine-stop"); 179 } 180 } 181 182 void ConcurrentG1RefineThread::stop() { 183 // it is ok to take late safepoints here, if needed 184 { 185 MutexLockerEx mu(Terminator_lock); 186 _should_terminate = true; 187 } 188 189 stop_service(); 190 191 { 192 MutexLockerEx mu(Terminator_lock); 193 while (!_has_terminated) { 194 Terminator_lock->wait(); 195 } 196 } 197 } 198 199 void ConcurrentG1RefineThread::stop_service() { 200 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 201 _monitor->notify(); 202 }