Sat, 06 Oct 2012 01:17:44 -0700
7127708: G1: change task num types from int to uint in concurrent mark
Summary: Change the type of various task num fields, parameters etc to unsigned and rename them to be more consistent with the other collectors. Code changes were also reviewed by Vitaly Davidovich.
Reviewed-by: johnc
Contributed-by: Kaushik Srenevasan <kaushik@twitter.com>
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/concurrentG1RefineThread.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/mutexLocker.hpp"
34 ConcurrentG1RefineThread::
35 ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next,
36 int worker_id_offset, int worker_id) :
37 ConcurrentGCThread(),
38 _worker_id_offset(worker_id_offset),
39 _worker_id(worker_id),
40 _active(false),
41 _next(next),
42 _monitor(NULL),
43 _cg1r(cg1r),
44 _vtime_accum(0.0)
45 {
47 // Each thread has its own monitor. The i-th thread is responsible for signalling
48 // to thread i+1 if the number of buffers in the queue exceeds a threashold for this
49 // thread. Monitors are also used to wake up the threads during termination.
50 // The 0th worker in notified by mutator threads and has a special monitor.
51 // The last worker is used for young gen rset size sampling.
52 if (worker_id > 0) {
53 _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true);
54 } else {
55 _monitor = DirtyCardQ_CBL_mon;
56 }
57 initialize();
58 create_and_start();
59 }
61 void ConcurrentG1RefineThread::initialize() {
62 if (_worker_id < cg1r()->worker_thread_num()) {
63 // Current thread activation threshold
64 _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(),
65 cg1r()->yellow_zone());
66 // A thread deactivates once the number of buffer reached a deactivation threshold
67 _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone());
68 } else {
69 set_active(true);
70 }
71 }
73 void ConcurrentG1RefineThread::sample_young_list_rs_lengths() {
74 G1CollectedHeap* g1h = G1CollectedHeap::heap();
75 G1CollectorPolicy* g1p = g1h->g1_policy();
76 if (g1p->adaptive_young_list_length()) {
77 int regions_visited = 0;
78 g1h->young_list()->rs_length_sampling_init();
79 while (g1h->young_list()->rs_length_sampling_more()) {
80 g1h->young_list()->rs_length_sampling_next();
81 ++regions_visited;
83 // we try to yield every time we visit 10 regions
84 if (regions_visited == 10) {
85 if (_sts.should_yield()) {
86 _sts.yield("G1 refine");
87 // we just abandon the iteration
88 break;
89 }
90 regions_visited = 0;
91 }
92 }
94 g1p->revise_young_list_target_length_if_necessary();
95 }
96 }
98 void ConcurrentG1RefineThread::run_young_rs_sampling() {
99 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
100 _vtime_start = os::elapsedVTime();
101 while(!_should_terminate) {
102 _sts.join();
103 sample_young_list_rs_lengths();
104 _sts.leave();
106 if (os::supports_vtime()) {
107 _vtime_accum = (os::elapsedVTime() - _vtime_start);
108 } else {
109 _vtime_accum = 0.0;
110 }
112 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
113 if (_should_terminate) {
114 break;
115 }
116 _monitor->wait(Mutex::_no_safepoint_check_flag, G1ConcRefinementServiceIntervalMillis);
117 }
118 }
120 void ConcurrentG1RefineThread::wait_for_completed_buffers() {
121 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
122 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
123 while (!_should_terminate && !is_active()) {
124 _monitor->wait(Mutex::_no_safepoint_check_flag);
125 }
126 }
128 bool ConcurrentG1RefineThread::is_active() {
129 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
130 return _worker_id > 0 ? _active : dcqs.process_completed_buffers();
131 }
133 void ConcurrentG1RefineThread::activate() {
134 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
135 if (_worker_id > 0) {
136 if (G1TraceConcRefinement) {
137 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
138 gclog_or_tty->print_cr("G1-Refine-activated worker %d, on threshold %d, current %d",
139 _worker_id, _threshold, (int)dcqs.completed_buffers_num());
140 }
141 set_active(true);
142 } else {
143 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
144 dcqs.set_process_completed(true);
145 }
146 _monitor->notify();
147 }
149 void ConcurrentG1RefineThread::deactivate() {
150 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
151 if (_worker_id > 0) {
152 if (G1TraceConcRefinement) {
153 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
154 gclog_or_tty->print_cr("G1-Refine-deactivated worker %d, off threshold %d, current %d",
155 _worker_id, _deactivation_threshold, (int)dcqs.completed_buffers_num());
156 }
157 set_active(false);
158 } else {
159 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
160 dcqs.set_process_completed(false);
161 }
162 }
164 void ConcurrentG1RefineThread::run() {
165 initialize_in_thread();
166 wait_for_universe_init();
168 if (_worker_id >= cg1r()->worker_thread_num()) {
169 run_young_rs_sampling();
170 terminate();
171 return;
172 }
174 _vtime_start = os::elapsedVTime();
175 while (!_should_terminate) {
176 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
178 // Wait for work
179 wait_for_completed_buffers();
181 if (_should_terminate) {
182 break;
183 }
185 _sts.join();
187 do {
188 int curr_buffer_num = (int)dcqs.completed_buffers_num();
189 // If the number of the buffers falls down into the yellow zone,
190 // that means that the transition period after the evacuation pause has ended.
191 if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {
192 dcqs.set_completed_queue_padding(0);
193 }
195 if (_worker_id > 0 && curr_buffer_num <= _deactivation_threshold) {
196 // If the number of the buffer has fallen below our threshold
197 // we should deactivate. The predecessor will reactivate this
198 // thread should the number of the buffers cross the threshold again.
199 deactivate();
200 break;
201 }
203 // Check if we need to activate the next thread.
204 if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) {
205 _next->activate();
206 }
207 } while (dcqs.apply_closure_to_completed_buffer(_worker_id + _worker_id_offset, cg1r()->green_zone()));
209 // We can exit the loop above while being active if there was a yield request.
210 if (is_active()) {
211 deactivate();
212 }
214 _sts.leave();
216 if (os::supports_vtime()) {
217 _vtime_accum = (os::elapsedVTime() - _vtime_start);
218 } else {
219 _vtime_accum = 0.0;
220 }
221 }
222 assert(_should_terminate, "just checking");
223 terminate();
224 }
227 void ConcurrentG1RefineThread::yield() {
228 if (G1TraceConcRefinement) {
229 gclog_or_tty->print_cr("G1-Refine-yield");
230 }
231 _sts.yield("G1 refine");
232 if (G1TraceConcRefinement) {
233 gclog_or_tty->print_cr("G1-Refine-yield-end");
234 }
235 }
237 void ConcurrentG1RefineThread::stop() {
238 // it is ok to take late safepoints here, if needed
239 {
240 MutexLockerEx mu(Terminator_lock);
241 _should_terminate = true;
242 }
244 {
245 MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);
246 _monitor->notify();
247 }
249 {
250 MutexLockerEx mu(Terminator_lock);
251 while (!_has_terminated) {
252 Terminator_lock->wait();
253 }
254 }
255 if (G1TraceConcRefinement) {
256 gclog_or_tty->print_cr("G1-Refine-stop");
257 }
258 }
260 void ConcurrentG1RefineThread::print() const {
261 print_on(tty);
262 }
264 void ConcurrentG1RefineThread::print_on(outputStream* st) const {
265 st->print("\"G1 Concurrent Refinement Thread#%d\" ", _worker_id);
266 Thread::print_on(st);
267 st->cr();
268 }