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 set_active(true);
93 } else {
94 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
95 dcqs.set_process_completed(true);
96 }
97 _monitor->notify();
98 }
99
100 void ConcurrentG1RefineThread::deactivate() {
101 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
102 if (!is_primary()) {
103 set_active(false);
104 } else {
105 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
106 dcqs.set_process_completed(false);
107 }
108 }
109
110 void ConcurrentG1RefineThread::run() {
111 initialize_in_thread();
112 wait_for_universe_init();
113
114 run_service();
115
116 terminate();
117 }
118
119 void ConcurrentG1RefineThread::run_service() {
120 _vtime_start = os::elapsedVTime();
121
122 while (!_should_terminate) {
123 // Wait for work
124 wait_for_completed_buffers();
125 if (_should_terminate) {
126 break;
127 }
128
129 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
130 log_debug(gc, refine)("Activated %d, on threshold: %d, current: %d",
131 _worker_id, _threshold, dcqs.completed_buffers_num());
132
133 {
134 SuspendibleThreadSetJoiner sts_join;
135
136 do {
137 int curr_buffer_num = (int)dcqs.completed_buffers_num();
138 // If the number of the buffers falls down into the yellow zone,
139 // that means that the transition period after the evacuation pause has ended.
140 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {
141 dcqs.set_completed_queue_padding(0);
142 }
143
144 // Check if we need to activate the next thread.
145 if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) {
146 _next->activate();
147 }
148 } while (dcqs.apply_closure_to_completed_buffer(_refine_closure,
149 _worker_id + _worker_id_offset,
150 _deactivation_threshold,
151 false /* during_pause */));
152
153 deactivate();
154 log_debug(gc, refine)("Deactivated %d, off threshold: %d, current: %d",
155 _worker_id, _deactivation_threshold,
156 dcqs.completed_buffers_num());
157 }
158
159 if (os::supports_vtime()) {
160 _vtime_accum = (os::elapsedVTime() - _vtime_start);
161 } else {
162 _vtime_accum = 0.0;
163 }
164 }
165
166 log_debug(gc, refine)("Stopping %d", _worker_id);
167 }
168
169 void ConcurrentG1RefineThread::stop() {
170 // it is ok to take late safepoints here, if needed
171 {
172 MutexLockerEx mu(Terminator_lock);
173 _should_terminate = true;
174 }
175
176 stop_service();
177
178 {
179 MutexLockerEx mu(Terminator_lock);
180 while (!_has_terminated) {
181 Terminator_lock->wait();
182 }
183 }
184 }
185
186 void ConcurrentG1RefineThread::stop_service() {
187 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
188 _monitor->notify();
189 }