1 /*
2 * Copyright (c) 2013, 2020, Red Hat, Inc. 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
27 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
28 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
29 #include "gc/shenandoah/shenandoahControlThread.hpp"
30 #include "gc/shenandoah/shenandoahFreeSet.hpp"
31 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
34 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
35 #include "gc/shenandoah/shenandoahUtils.hpp"
36 #include "gc/shenandoah/shenandoahVMOperations.hpp"
37 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
38 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
39 #include "memory/iterator.hpp"
40 #include "memory/universe.hpp"
41 #include "runtime/atomic.hpp"
42
43 ShenandoahControlThread::ShenandoahControlThread() :
44 ConcurrentGCThread(),
45 _alloc_failure_waiters_lock(Mutex::leaf, "ShenandoahAllocFailureGC_lock", true, Monitor::_safepoint_check_always),
46 _gc_waiters_lock(Mutex::leaf, "ShenandoahRequestedGC_lock", true, Monitor::_safepoint_check_always),
47 _periodic_task(this),
48 _requested_gc_cause(GCCause::_no_cause_specified),
49 _degen_point(ShenandoahHeap::_degenerated_outside_cycle),
50 _allocs_seen(0) {
51
52 reset_gc_id();
53 create_and_start(ShenandoahCriticalControlThreadPriority ? CriticalPriority : NearMaxPriority);
54 _periodic_task.enroll();
55 _periodic_satb_flush_task.enroll();
56 if (ShenandoahPacing) {
57 _periodic_pacer_notify_task.enroll();
58 }
59 }
60
61 ShenandoahControlThread::~ShenandoahControlThread() {
62 // This is here so that super is called.
63 }
64
65 void ShenandoahPeriodicTask::task() {
66 _thread->handle_force_counters_update();
67 _thread->handle_counters_update();
68 }
69
70 void ShenandoahPeriodicSATBFlushTask::task() {
71 ShenandoahHeap::heap()->force_satb_flush_all_threads();
72 }
73
74 void ShenandoahPeriodicPacerNotify::task() {
75 assert(ShenandoahPacing, "Should not be here otherwise");
76 ShenandoahHeap::heap()->pacer()->notify_waiters();
77 }
78
79 void ShenandoahControlThread::run_service() {
80 ShenandoahHeap* heap = ShenandoahHeap::heap();
81
82 GCMode default_mode = concurrent_normal;
83 GCCause::Cause default_cause = GCCause::_shenandoah_concurrent_gc;
84 int sleep = ShenandoahControlIntervalMin;
85
86 double last_shrink_time = os::elapsedTime();
87 double last_sleep_adjust_time = os::elapsedTime();
88
89 // Shrink period avoids constantly polling regions for shrinking.
90 // Having a period 10x lower than the delay would mean we hit the
91 // shrinking with lag of less than 1/10-th of true delay.
92 // ShenandoahUncommitDelay is in msecs, but shrink_period is in seconds.
93 double shrink_period = (double)ShenandoahUncommitDelay / 1000 / 10;
94
95 ShenandoahCollectorPolicy* policy = heap->shenandoah_policy();
96 ShenandoahHeuristics* heuristics = heap->heuristics();
97 while (!in_graceful_shutdown() && !should_terminate()) {
98 // Figure out if we have pending requests.
99 bool alloc_failure_pending = _alloc_failure_gc.is_set();
100 bool explicit_gc_requested = _gc_requested.is_set() && is_explicit_gc(_requested_gc_cause);
101 bool implicit_gc_requested = _gc_requested.is_set() && !is_explicit_gc(_requested_gc_cause);
102
103 // This control loop iteration have seen this much allocations.
104 size_t allocs_seen = Atomic::xchg(&_allocs_seen, (size_t)0);
105
106 // Choose which GC mode to run in. The block below should select a single mode.
107 GCMode mode = none;
108 GCCause::Cause cause = GCCause::_last_gc_cause;
109 ShenandoahHeap::ShenandoahDegenPoint degen_point = ShenandoahHeap::_degenerated_unset;
110
111 if (alloc_failure_pending) {
112 // Allocation failure takes precedence: we have to deal with it first thing
113 log_info(gc)("Trigger: Handle Allocation Failure");
114
115 cause = GCCause::_allocation_failure;
116
117 // Consume the degen point, and seed it with default value
118 degen_point = _degen_point;
119 _degen_point = ShenandoahHeap::_degenerated_outside_cycle;
120
121 if (ShenandoahDegeneratedGC && heuristics->should_degenerate_cycle()) {
122 heuristics->record_allocation_failure_gc();
123 policy->record_alloc_failure_to_degenerated(degen_point);
124 mode = stw_degenerated;
125 } else {
126 heuristics->record_allocation_failure_gc();
127 policy->record_alloc_failure_to_full();
128 mode = stw_full;
129 }
130
131 } else if (explicit_gc_requested) {
132 cause = _requested_gc_cause;
133 log_info(gc)("Trigger: Explicit GC request (%s)", GCCause::to_string(cause));
134
135 heuristics->record_requested_gc();
136
137 if (ExplicitGCInvokesConcurrent) {
138 policy->record_explicit_to_concurrent();
139 mode = default_mode;
140 // Unload and clean up everything
141 heap->set_process_references(heuristics->can_process_references());
142 heap->set_unload_classes(heuristics->can_unload_classes());
143 } else {
144 policy->record_explicit_to_full();
145 mode = stw_full;
146 }
147 } else if (implicit_gc_requested) {
148 cause = _requested_gc_cause;
149 log_info(gc)("Trigger: Implicit GC request (%s)", GCCause::to_string(cause));
150
151 heuristics->record_requested_gc();
152
153 if (ShenandoahImplicitGCInvokesConcurrent) {
154 policy->record_implicit_to_concurrent();
155 mode = default_mode;
156
157 // Unload and clean up everything
158 heap->set_process_references(heuristics->can_process_references());
159 heap->set_unload_classes(heuristics->can_unload_classes());
160 } else {
161 policy->record_implicit_to_full();
162 mode = stw_full;
163 }
164 } else {
165 // Potential normal cycle: ask heuristics if it wants to act
166 if (heuristics->should_start_gc()) {
167 mode = default_mode;
168 cause = default_cause;
169 }
170
171 // Ask policy if this cycle wants to process references or unload classes
172 heap->set_process_references(heuristics->should_process_references());
173 heap->set_unload_classes(heuristics->should_unload_classes());
174 }
175
176 // Blow all soft references on this cycle, if handling allocation failure,
177 // either implicit or explicit GC request, or we are requested to do so unconditionally.
178 if (alloc_failure_pending || implicit_gc_requested || explicit_gc_requested || ShenandoahAlwaysClearSoftRefs) {
179 heap->soft_ref_policy()->set_should_clear_all_soft_refs(true);
180 }
181
182 bool gc_requested = (mode != none);
183 assert (!gc_requested || cause != GCCause::_last_gc_cause, "GC cause should be set");
184
185 if (gc_requested) {
186 // GC is starting, bump the internal ID
187 update_gc_id();
188
189 heap->reset_bytes_allocated_since_gc_start();
190
191 // Use default constructor to snapshot the Metaspace state before GC.
192 metaspace::MetaspaceSizesSnapshot meta_sizes;
193
194 // If GC was requested, we are sampling the counters even without actual triggers
195 // from allocation machinery. This captures GC phases more accurately.
196 set_forced_counters_update(true);
197
198 // If GC was requested, we better dump freeset data for performance debugging
199 {
200 ShenandoahHeapLocker locker(heap->lock());
201 heap->free_set()->log_status();
202 }
203
204 switch (mode) {
205 case concurrent_normal:
206 service_concurrent_normal_cycle(cause);
207 break;
208 case stw_degenerated:
209 service_stw_degenerated_cycle(cause, degen_point);
210 break;
211 case stw_full:
212 service_stw_full_cycle(cause);
213 break;
214 default:
215 ShouldNotReachHere();
216 }
217
218 // If this was the requested GC cycle, notify waiters about it
219 if (explicit_gc_requested || implicit_gc_requested) {
220 notify_gc_waiters();
221 }
222
223 // If this was the allocation failure GC cycle, notify waiters about it
224 if (alloc_failure_pending) {
225 notify_alloc_failure_waiters();
226 }
227
228 // Report current free set state at the end of cycle, whether
229 // it is a normal completion, or the abort.
230 {
231 ShenandoahHeapLocker locker(heap->lock());
232 heap->free_set()->log_status();
233
234 // Notify Universe about new heap usage. This has implications for
235 // global soft refs policy, and we better report it every time heap
236 // usage goes down.
237 Universe::update_heap_info_at_gc();
238 }
239
240 // Disable forced counters update, and update counters one more time
241 // to capture the state at the end of GC session.
242 handle_force_counters_update();
243 set_forced_counters_update(false);
244
245 // Retract forceful part of soft refs policy
246 heap->soft_ref_policy()->set_should_clear_all_soft_refs(false);
247
248 // Clear metaspace oom flag, if current cycle unloaded classes
249 if (heap->unload_classes()) {
250 heuristics->clear_metaspace_oom();
251 }
252
253 // Commit worker statistics to cycle data
254 heap->phase_timings()->flush_par_workers_to_cycle();
255 if (ShenandoahPacing) {
256 heap->pacer()->flush_stats_to_cycle();
257 }
258
259 // Print GC stats for current cycle
260 {
261 LogTarget(Info, gc, stats) lt;
262 if (lt.is_enabled()) {
263 ResourceMark rm;
264 LogStream ls(lt);
265 heap->phase_timings()->print_cycle_on(&ls);
266 if (ShenandoahPacing) {
267 heap->pacer()->print_cycle_on(&ls);
268 }
269 }
270 }
271
272 // Commit statistics to globals
273 heap->phase_timings()->flush_cycle_to_global();
274
275 // Print Metaspace change following GC (if logging is enabled).
276 MetaspaceUtils::print_metaspace_change(meta_sizes);
277
278 heap->next_whole_heap_examined();
279
280 // GC is over, we are at idle now
281 if (ShenandoahPacing) {
282 heap->pacer()->setup_for_idle();
283 }
284 } else {
285 // Allow allocators to know we have seen this much regions
286 if (ShenandoahPacing && (allocs_seen > 0)) {
287 heap->pacer()->report_alloc(allocs_seen);
288 }
289 }
290
291 double current = os::elapsedTime();
292
293 if (ShenandoahUncommit && (explicit_gc_requested || (current - last_shrink_time > shrink_period))) {
294 // Try to uncommit enough stale regions. Explicit GC tries to uncommit everything.
295 // Regular paths uncommit only occasionally.
296 double shrink_before = explicit_gc_requested ?
297 current :
298 current - (ShenandoahUncommitDelay / 1000.0);
299 service_uncommit(shrink_before);
300 heap->phase_timings()->flush_cycle_to_global();
301 last_shrink_time = current;
302 }
303
304 // Wait before performing the next action. If allocation happened during this wait,
305 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle,
306 // back off exponentially.
307 if (_heap_changed.try_unset()) {
308 sleep = ShenandoahControlIntervalMin;
309 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){
310 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2));
311 last_sleep_adjust_time = current;
312 }
313 os::naked_short_sleep(sleep);
314 }
315
316 // Wait for the actual stop(), can't leave run_service() earlier.
317 while (!should_terminate()) {
318 os::naked_short_sleep(ShenandoahControlIntervalMin);
319 }
320 }
321
322 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) {
323 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during
324 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there.
325 // If second allocation failure happens during Degenerated GC cycle (for example, when GC
326 // tries to evac something and no memory is available), cycle degrades to Full GC.
327 //
328 // There are also a shortcut through the normal cycle: immediate garbage shortcut, when
329 // heuristics says there are no regions to compact, and all the collection comes from immediately
330 // reclaimable regions.
331 //
332 // ................................................................................................
333 //
334 // (immediate garbage shortcut) Concurrent GC
335 // /-------------------------------------------\
336 // | |
337 // | |
338 // | |
339 // | v
340 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END]
341 // | | | ^
342 // | (af) | (af) | (af) |
343 // ..................|....................|.................|..............|.......................
344 // | | | |
345 // | | | | Degenerated GC
346 // v v v |
347 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o
348 // | | | ^
349 // | (af) | (af) | (af) |
350 // ..................|....................|.................|..............|.......................
351 // | | | |
352 // | v | | Full GC
353 // \------------------->o<----------------/ |
354 // | |
355 // v |
356 // Full GC --------------------------/
357 //
358 ShenandoahHeap* heap = ShenandoahHeap::heap();
359
360 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_outside_cycle)) return;
361
362 GCIdMark gc_id_mark;
363 ShenandoahGCSession session(cause);
364
365 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
366
367 // Reset for upcoming marking
368 heap->entry_reset();
369
370 // Start initial mark under STW
371 heap->vmop_entry_init_mark();
372
373 // Continue concurrent mark
374 heap->entry_mark();
375 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_mark)) return;
376
377 // If not cancelled, can try to concurrently pre-clean
378 heap->entry_preclean();
379
380 // Complete marking under STW, and start evacuation
381 heap->vmop_entry_final_mark();
382
383 // Process weak roots that might still point to regions that would be broken by cleanup
384 if (heap->is_concurrent_weak_root_in_progress()) {
385 heap->entry_weak_roots();
386 }
387
388 // Final mark might have reclaimed some immediate garbage, kick cleanup to reclaim
389 // the space. This would be the last action if there is nothing to evacuate.
390 heap->entry_cleanup_early();
391
392 {
393 ShenandoahHeapLocker locker(heap->lock());
394 heap->free_set()->log_status();
395 }
396
397 // Perform concurrent class unloading
398 if (heap->is_concurrent_weak_root_in_progress()) {
399 heap->entry_class_unloading();
400 }
401
402 // Processing strong roots
403 // This may be skipped if there is nothing to update/evacuate.
404 // If so, strong_root_in_progress would be unset.
405 if (heap->is_concurrent_strong_root_in_progress()) {
406 heap->entry_strong_roots();
407 }
408
409 // Continue the cycle with evacuation and optional update-refs.
410 // This may be skipped if there is nothing to evacuate.
411 // If so, evac_in_progress would be unset by collection set preparation code.
412 if (heap->is_evacuation_in_progress()) {
413 // Concurrently evacuate
414 heap->entry_evac();
415 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_evac)) return;
416
417 // Perform update-refs phase.
418 heap->vmop_entry_init_updaterefs();
419 heap->entry_updaterefs();
420 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_updaterefs)) return;
421
422 heap->vmop_entry_final_updaterefs();
423
424 // Update references freed up collection set, kick the cleanup to reclaim the space.
425 heap->entry_cleanup_complete();
426 }
427
428 // Cycle is complete
429 heap->heuristics()->record_success_concurrent();
430 heap->shenandoah_policy()->record_success_concurrent();
431 }
432
433 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point) {
434 ShenandoahHeap* heap = ShenandoahHeap::heap();
435 if (heap->cancelled_gc()) {
436 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting");
437 if (!in_graceful_shutdown()) {
438 assert (_degen_point == ShenandoahHeap::_degenerated_outside_cycle,
439 "Should not be set yet: %s", ShenandoahHeap::degen_point_to_string(_degen_point));
440 _degen_point = point;
441 }
442 return true;
443 }
444 return false;
445 }
446
447 void ShenandoahControlThread::stop_service() {
448 // Nothing to do here.
449 }
450
451 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) {
452 GCIdMark gc_id_mark;
453 ShenandoahGCSession session(cause);
454
455 ShenandoahHeap* heap = ShenandoahHeap::heap();
456 heap->vmop_entry_full(cause);
457
458 heap->heuristics()->record_success_full();
459 heap->shenandoah_policy()->record_success_full();
460 }
461
462 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point) {
463 assert (point != ShenandoahHeap::_degenerated_unset, "Degenerated point should be set");
464
465 GCIdMark gc_id_mark;
466 ShenandoahGCSession session(cause);
467
468 ShenandoahHeap* heap = ShenandoahHeap::heap();
469 heap->vmop_degenerated(point);
470
471 heap->heuristics()->record_success_degenerated();
472 heap->shenandoah_policy()->record_success_degenerated();
473 }
474
475 void ShenandoahControlThread::service_uncommit(double shrink_before) {
476 ShenandoahHeap* heap = ShenandoahHeap::heap();
477
478 // Determine if there is work to do. This avoids taking heap lock if there is
479 // no work available, avoids spamming logs with superfluous logging messages,
480 // and minimises the amount of work while locks are taken.
481
482 if (heap->committed() <= heap->min_capacity()) return;
483
484 bool has_work = false;
485 for (size_t i = 0; i < heap->num_regions(); i++) {
486 ShenandoahHeapRegion *r = heap->get_region(i);
487 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
488 has_work = true;
489 break;
490 }
491 }
492
493 if (has_work) {
494 heap->entry_uncommit(shrink_before);
495 }
496 }
497
498 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const {
499 return GCCause::is_user_requested_gc(cause) ||
500 GCCause::is_serviceability_requested_gc(cause);
501 }
502
503 void ShenandoahControlThread::request_gc(GCCause::Cause cause) {
504 assert(GCCause::is_user_requested_gc(cause) ||
505 GCCause::is_serviceability_requested_gc(cause) ||
506 cause == GCCause::_metadata_GC_clear_soft_refs ||
507 cause == GCCause::_full_gc_alot ||
508 cause == GCCause::_wb_full_gc ||
509 cause == GCCause::_scavenge_alot,
510 "only requested GCs here");
511
512 if (is_explicit_gc(cause)) {
513 if (!DisableExplicitGC) {
514 handle_requested_gc(cause);
515 }
516 } else {
517 handle_requested_gc(cause);
518 }
519 }
520
521 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) {
522 // Make sure we have at least one complete GC cycle before unblocking
523 // from the explicit GC request.
524 //
525 // This is especially important for weak references cleanup and/or native
526 // resources (e.g. DirectByteBuffers) machinery: when explicit GC request
527 // comes very late in the already running cycle, it would miss lots of new
528 // opportunities for cleanup that were made available before the caller
529 // requested the GC.
530
531 MonitorLocker ml(&_gc_waiters_lock);
532 size_t current_gc_id = get_gc_id();
533 size_t required_gc_id = current_gc_id + 1;
534 while (current_gc_id < required_gc_id) {
535 _gc_requested.set();
536 _requested_gc_cause = cause;
537 ml.wait();
538 current_gc_id = get_gc_id();
539 }
540 }
541
542 void ShenandoahControlThread::handle_alloc_failure(ShenandoahAllocRequest& req) {
543 ShenandoahHeap* heap = ShenandoahHeap::heap();
544
545 assert(current()->is_Java_thread(), "expect Java thread here");
546
547 if (try_set_alloc_failure_gc()) {
548 // Only report the first allocation failure
549 log_info(gc)("Failed to allocate %s, " SIZE_FORMAT "%s",
550 req.type_string(),
551 byte_size_in_proper_unit(req.size() * HeapWordSize), proper_unit_for_byte_size(req.size() * HeapWordSize));
552
553 // Now that alloc failure GC is scheduled, we can abort everything else
554 heap->cancel_gc(GCCause::_allocation_failure);
555 }
556
557 MonitorLocker ml(&_alloc_failure_waiters_lock);
558 while (is_alloc_failure_gc()) {
559 ml.wait();
560 }
561 }
562
563 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) {
564 ShenandoahHeap* heap = ShenandoahHeap::heap();
565
566 if (try_set_alloc_failure_gc()) {
567 // Only report the first allocation failure
568 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation",
569 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
570 }
571
572 // Forcefully report allocation failure
573 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac);
574 }
575
576 void ShenandoahControlThread::notify_alloc_failure_waiters() {
577 _alloc_failure_gc.unset();
578 MonitorLocker ml(&_alloc_failure_waiters_lock);
579 ml.notify_all();
580 }
581
582 bool ShenandoahControlThread::try_set_alloc_failure_gc() {
583 return _alloc_failure_gc.try_set();
584 }
585
586 bool ShenandoahControlThread::is_alloc_failure_gc() {
587 return _alloc_failure_gc.is_set();
588 }
589
590 void ShenandoahControlThread::notify_gc_waiters() {
591 _gc_requested.unset();
592 MonitorLocker ml(&_gc_waiters_lock);
593 ml.notify_all();
594 }
595
596 void ShenandoahControlThread::handle_counters_update() {
597 if (_do_counters_update.is_set()) {
598 _do_counters_update.unset();
599 ShenandoahHeap::heap()->monitoring_support()->update_counters();
600 }
601 }
602
603 void ShenandoahControlThread::handle_force_counters_update() {
604 if (_force_counters_update.is_set()) {
605 _do_counters_update.unset(); // reset these too, we do update now!
606 ShenandoahHeap::heap()->monitoring_support()->update_counters();
607 }
608 }
609
610 void ShenandoahControlThread::notify_heap_changed() {
611 // This is called from allocation path, and thus should be fast.
612
613 // Update monitoring counters when we took a new region. This amortizes the
614 // update costs on slow path.
615 if (_do_counters_update.is_unset()) {
616 _do_counters_update.set();
617 }
618 // Notify that something had changed.
619 if (_heap_changed.is_unset()) {
620 _heap_changed.set();
621 }
622 }
623
624 void ShenandoahControlThread::pacing_notify_alloc(size_t words) {
625 assert(ShenandoahPacing, "should only call when pacing is enabled");
626 Atomic::add(&_allocs_seen, words);
627 }
628
629 void ShenandoahControlThread::set_forced_counters_update(bool value) {
630 _force_counters_update.set_cond(value);
631 }
632
633 void ShenandoahControlThread::reset_gc_id() {
634 Atomic::store(&_gc_id, (size_t)0);
635 }
636
637 void ShenandoahControlThread::update_gc_id() {
638 Atomic::inc(&_gc_id);
639 }
640
641 size_t ShenandoahControlThread::get_gc_id() {
642 return Atomic::load(&_gc_id);
643 }
644
645 void ShenandoahControlThread::print() const {
646 print_on(tty);
647 }
648
649 void ShenandoahControlThread::print_on(outputStream* st) const {
650 st->print("Shenandoah Concurrent Thread");
651 Thread::print_on(st);
652 st->cr();
653 }
654
655 void ShenandoahControlThread::start() {
656 create_and_start();
657 }
658
659 void ShenandoahControlThread::prepare_for_graceful_shutdown() {
660 _graceful_shutdown.set();
661 }
662
663 bool ShenandoahControlThread::in_graceful_shutdown() {
664 return _graceful_shutdown.is_set();
665 }