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/suspendibleThreadSet.hpp" 30 #include "logging/log.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 size_t activate, size_t deactivate) : 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 _activation_threshold(activate), 50 _deactivation_threshold(deactivate) 51 { 52 53 // Each thread has its own monitor. The i-th thread is responsible for signaling 54 // to thread i+1 if the number of buffers in the queue exceeds a threshold for this 55 // thread. Monitors are also used to wake up the threads during termination. 56 // The 0th (primary) worker is notified by mutator threads and has a special monitor. 57 if (!is_primary()) { 58 _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true, 59 Monitor::_safepoint_check_never); 60 } else { 61 _monitor = DirtyCardQ_CBL_mon; 62 } 63 64 // set name 65 set_name("G1 Refine#%d", worker_id); 66 create_and_start(); 67 } 68 69 void ConcurrentG1RefineThread::update_thresholds(size_t activate, 70 size_t deactivate) { 71 assert(deactivate < activate, "precondition"); 72 _activation_threshold = activate; 73 _deactivation_threshold = deactivate; 74 } 75 76 void ConcurrentG1RefineThread::wait_for_completed_buffers() { 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 set_active(true); 92 } else { 93 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 94 dcqs.set_process_completed(true); 95 } 96 _monitor->notify(); 97 } 98 99 void ConcurrentG1RefineThread::deactivate() { 100 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 101 if (!is_primary()) { 102 set_active(false); 103 } else { 104 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 105 dcqs.set_process_completed(false); 106 } 107 } 108 109 void ConcurrentG1RefineThread::run_service() { 110 _vtime_start = os::elapsedVTime(); 111 112 while (!should_terminate()) { 113 // Wait for work 114 wait_for_completed_buffers(); 115 if (should_terminate()) { 116 break; 117 } 118 119 size_t buffers_processed = 0; 120 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 121 log_debug(gc, refine)("Activated %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT, 122 _worker_id, _activation_threshold, dcqs.completed_buffers_num()); 123 124 { 125 SuspendibleThreadSetJoiner sts_join; 126 127 while (!should_terminate()) { 128 if (sts_join.should_yield()) { 129 sts_join.yield(); 130 continue; // Re-check for termination after yield delay. 131 } 132 133 size_t curr_buffer_num = dcqs.completed_buffers_num(); 134 // If the number of the buffers falls down into the yellow zone, 135 // that means that the transition period after the evacuation pause has ended. 136 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) { 137 dcqs.set_completed_queue_padding(0); 138 } 139 140 // Check if we need to activate the next thread. 141 if ((_next != NULL) && 142 !_next->is_active() && 143 (curr_buffer_num > _next->_activation_threshold)) { 144 _next->activate(); 145 } 146 147 // Process the next buffer, if there are enough left. 148 if (!dcqs.apply_closure_to_completed_buffer(_refine_closure, 149 _worker_id + _worker_id_offset, 150 _deactivation_threshold, 151 false /* during_pause */)) { 152 break; // Deactivate, number of buffers fell below threshold. 153 } 154 ++buffers_processed; 155 } 156 } 157 158 deactivate(); 159 log_debug(gc, refine)("Deactivated %d, off threshold: " SIZE_FORMAT 160 ", current: " SIZE_FORMAT ", processed: " SIZE_FORMAT, 161 _worker_id, _deactivation_threshold, 162 dcqs.completed_buffers_num(), 163 buffers_processed); 164 165 if (os::supports_vtime()) { 166 _vtime_accum = (os::elapsedVTime() - _vtime_start); 167 } else { 168 _vtime_accum = 0.0; 169 } 170 } 171 172 log_debug(gc, refine)("Stopping %d", _worker_id); 173 } 174 175 void ConcurrentG1RefineThread::stop_service() { 176 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); 177 _monitor->notify(); 178 }