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(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 =
74 MAX2(_threshold - MIN2(_threshold, cg1r()->thread_threshold_step()),
75 cg1r()->green_zone());
76 }
77
78 void ConcurrentG1RefineThread::wait_for_completed_buffers() {
79 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
80 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
81 while (!_should_terminate && !is_active()) {
82 _monitor->wait(Mutex::_no_safepoint_check_flag);
83 }
84 }
85
86 bool ConcurrentG1RefineThread::is_active() {
87 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
88 return is_primary() ? dcqs.process_completed_buffers() : _active;
89 }
90
91 void ConcurrentG1RefineThread::activate() {
92 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
93 if (!is_primary()) {
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 set_active(false);
106 } else {
107 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
108 dcqs.set_process_completed(false);
109 }
110 }
111
112 void ConcurrentG1RefineThread::run() {
113 initialize_in_thread();
114 wait_for_universe_init();
115
116 run_service();
117
118 terminate();
119 }
120
121 void ConcurrentG1RefineThread::run_service() {
122 _vtime_start = os::elapsedVTime();
123
124 while (!_should_terminate) {
125 // Wait for work
126 wait_for_completed_buffers();
127 if (_should_terminate) {
128 break;
129 }
130
131 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
132 log_debug(gc, refine)("Activated %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,
133 _worker_id, _threshold, dcqs.completed_buffers_num());
134
135 {
136 SuspendibleThreadSetJoiner sts_join;
137
138 do {
139 size_t curr_buffer_num = dcqs.completed_buffers_num();
140 // If the number of the buffers falls down into the yellow zone,
141 // that means that the transition period after the evacuation pause has ended.
142 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {
143 dcqs.set_completed_queue_padding(0);
144 }
145
146 // Check if we need to activate the next thread.
147 if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) {
148 _next->activate();
149 }
150 } while (dcqs.apply_closure_to_completed_buffer(_refine_closure,
151 _worker_id + _worker_id_offset,
152 _deactivation_threshold,
153 false /* during_pause */));
154
155 deactivate();
156 log_debug(gc, refine)("Deactivated %d, off threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,
157 _worker_id, _deactivation_threshold,
158 dcqs.completed_buffers_num());
159 }
160
161 if (os::supports_vtime()) {
162 _vtime_accum = (os::elapsedVTime() - _vtime_start);
163 } else {
164 _vtime_accum = 0.0;
165 }
166 }
167
168 log_debug(gc, refine)("Stopping %d", _worker_id);
169 }
170
171 void ConcurrentG1RefineThread::stop() {
172 // it is ok to take late safepoints here, if needed
173 {
174 MutexLockerEx mu(Terminator_lock);
175 _should_terminate = true;
176 }
177
178 stop_service();
179
180 {
181 MutexLockerEx mu(Terminator_lock);
182 while (!_has_terminated) {
183 Terminator_lock->wait();
184 }
185 }
186 }
187
188 void ConcurrentG1RefineThread::stop_service() {
189 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
190 _monitor->notify();
191 }