1 /*
2 * Copyright (c) 2001, 2017, 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/g1ConcurrentRefine.hpp"
27 #include "gc/g1/g1ConcurrentRefineThread.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1RemSet.hpp"
30 #include "gc/shared/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 G1ConcurrentRefineThread::G1ConcurrentRefineThread(G1ConcurrentRefine* cr,
37 G1ConcurrentRefineThread *next,
38 uint worker_id_offset,
39 uint worker_id,
40 size_t activate,
41 size_t deactivate) :
42 ConcurrentGCThread(),
43 _worker_id_offset(worker_id_offset),
44 _worker_id(worker_id),
45 _active(false),
46 _next(next),
47 _monitor(NULL),
48 _cr(cr),
49 _vtime_accum(0.0),
50 _activation_threshold(activate),
51 _deactivation_threshold(deactivate)
52 {
53
54 // Each thread has its own monitor. The i-th thread is responsible for signaling
55 // to thread i+1 if the number of buffers in the queue exceeds a threshold for this
56 // thread. Monitors are also used to wake up the threads during termination.
57 // The 0th (primary) worker is notified by mutator threads and has a special monitor.
58 if (!is_primary()) {
59 _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true,
60 Monitor::_safepoint_check_never);
61 } else {
62 _monitor = DirtyCardQ_CBL_mon;
63 }
64
65 // set name
66 set_name("G1 Refine#%d", worker_id);
67 create_and_start();
68 }
69
70 void G1ConcurrentRefineThread::update_thresholds(size_t activate,
71 size_t deactivate) {
72 assert(deactivate < activate, "precondition");
73 _activation_threshold = activate;
74 _deactivation_threshold = deactivate;
75 }
76
77 void G1ConcurrentRefineThread::wait_for_completed_buffers() {
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 G1ConcurrentRefineThread::is_active() {
85 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
86 return is_primary() ? dcqs.process_completed_buffers() : _active;
87 }
88
89 void G1ConcurrentRefineThread::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 G1ConcurrentRefineThread::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 G1ConcurrentRefineThread::run_service() {
111 _vtime_start = os::elapsedVTime();
112
113 while (!should_terminate()) {
114 // Wait for work
115 wait_for_completed_buffers();
116 if (should_terminate()) {
117 break;
118 }
119
120 size_t buffers_processed = 0;
121 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
122 log_debug(gc, refine)("Activated %d, on threshold: " SIZE_FORMAT ", current: " SIZE_FORMAT,
123 _worker_id, _activation_threshold, dcqs.completed_buffers_num());
124
125 {
126 SuspendibleThreadSetJoiner sts_join;
127
128 while (!should_terminate()) {
129 if (sts_join.should_yield()) {
130 sts_join.yield();
131 continue; // Re-check for termination after yield delay.
132 }
133
134 size_t curr_buffer_num = dcqs.completed_buffers_num();
135 // If the number of the buffers falls down into the yellow zone,
136 // that means that the transition period after the evacuation pause has ended.
137 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cr()->yellow_zone()) {
138 dcqs.set_completed_queue_padding(0);
139 }
140
141 // Check if we need to activate the next thread.
142 if ((_next != NULL) &&
143 !_next->is_active() &&
144 (curr_buffer_num > _next->_activation_threshold)) {
145 _next->activate();
146 }
147
148 // Process the next buffer, if there are enough left.
149 if (!dcqs.refine_completed_buffer_concurrently(_worker_id + _worker_id_offset, _deactivation_threshold)) {
150 break; // Deactivate, number of buffers fell below threshold.
151 }
152 ++buffers_processed;
153 }
154 }
155
156 deactivate();
157 log_debug(gc, refine)("Deactivated %d, off threshold: " SIZE_FORMAT
158 ", current: " SIZE_FORMAT ", processed: " SIZE_FORMAT,
159 _worker_id, _deactivation_threshold,
160 dcqs.completed_buffers_num(),
161 buffers_processed);
162
163 if (os::supports_vtime()) {
164 _vtime_accum = (os::elapsedVTime() - _vtime_start);
165 } else {
166 _vtime_accum = 0.0;
167 }
168 }
169
170 log_debug(gc, refine)("Stopping %d", _worker_id);
171 }
172
173 void G1ConcurrentRefineThread::stop_service() {
174 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
175 _monitor->notify();
176 }