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 // GC is over, we are at idle now
279 if (ShenandoahPacing) {
280 heap->pacer()->setup_for_idle();
281 }
282 } else {
283 // Allow allocators to know we have seen this much regions
284 if (ShenandoahPacing && (allocs_seen > 0)) {
285 heap->pacer()->report_alloc(allocs_seen);
286 }
287 }
288
289 double current = os::elapsedTime();
290
291 if (ShenandoahUncommit && (explicit_gc_requested || (current - last_shrink_time > shrink_period))) {
292 // Try to uncommit enough stale regions. Explicit GC tries to uncommit everything.
293 // Regular paths uncommit only occasionally.
294 double shrink_before = explicit_gc_requested ?
295 current :
296 current - (ShenandoahUncommitDelay / 1000.0);
297 service_uncommit(shrink_before);
298 heap->phase_timings()->flush_cycle_to_global();
299 last_shrink_time = current;
300 }
301
302 // Wait before performing the next action. If allocation happened during this wait,
303 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle,
304 // back off exponentially.
305 if (_heap_changed.try_unset()) {
306 sleep = ShenandoahControlIntervalMin;
307 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){
308 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2));
309 last_sleep_adjust_time = current;
310 }
311 os::naked_short_sleep(sleep);
312 }
313
314 // Wait for the actual stop(), can't leave run_service() earlier.
315 while (!should_terminate()) {
316 os::naked_short_sleep(ShenandoahControlIntervalMin);
317 }
318 }
319
320 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) {
321 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during
322 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there.
323 // If second allocation failure happens during Degenerated GC cycle (for example, when GC
324 // tries to evac something and no memory is available), cycle degrades to Full GC.
325 //
326 // There are also a shortcut through the normal cycle: immediate garbage shortcut, when
327 // heuristics says there are no regions to compact, and all the collection comes from immediately
328 // reclaimable regions.
329 //
330 // ................................................................................................
331 //
332 // (immediate garbage shortcut) Concurrent GC
333 // /-------------------------------------------\
334 // | |
335 // | |
336 // | |
337 // | v
338 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END]
339 // | | | ^
340 // | (af) | (af) | (af) |
341 // ..................|....................|.................|..............|.......................
342 // | | | |
343 // | | | | Degenerated GC
344 // v v v |
345 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o
346 // | | | ^
347 // | (af) | (af) | (af) |
348 // ..................|....................|.................|..............|.......................
349 // | | | |
350 // | v | | Full GC
351 // \------------------->o<----------------/ |
352 // | |
353 // v |
354 // Full GC --------------------------/
355 //
356 ShenandoahHeap* heap = ShenandoahHeap::heap();
357
358 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_outside_cycle)) return;
359
360 GCIdMark gc_id_mark;
361 ShenandoahGCSession session(cause);
362
363 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
364
365 // Reset for upcoming marking
366 heap->entry_reset();
367
368 // Start initial mark under STW
369 heap->vmop_entry_init_mark();
370
371 // Continue concurrent mark
372 heap->entry_mark();
373 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_mark)) return;
374
375 // If not cancelled, can try to concurrently pre-clean
376 heap->entry_preclean();
377
378 // Complete marking under STW, and start evacuation
379 heap->vmop_entry_final_mark();
380
381 // Process weak roots that might still point to regions that would be broken by cleanup
382 if (heap->is_concurrent_weak_root_in_progress()) {
383 heap->entry_weak_roots();
384 }
385
386 // Final mark might have reclaimed some immediate garbage, kick cleanup to reclaim
387 // the space. This would be the last action if there is nothing to evacuate.
388 heap->entry_cleanup_early();
389
390 {
391 ShenandoahHeapLocker locker(heap->lock());
392 heap->free_set()->log_status();
393 }
394
395 // Perform concurrent class unloading
396 if (heap->is_concurrent_weak_root_in_progress()) {
397 heap->entry_class_unloading();
398 }
399
400 // Processing strong roots
401 // This may be skipped if there is nothing to update/evacuate.
402 // If so, strong_root_in_progress would be unset.
403 if (heap->is_concurrent_strong_root_in_progress()) {
404 heap->entry_strong_roots();
405 }
406
407 // Continue the cycle with evacuation and optional update-refs.
408 // This may be skipped if there is nothing to evacuate.
409 // If so, evac_in_progress would be unset by collection set preparation code.
410 if (heap->is_evacuation_in_progress()) {
411 // Concurrently evacuate
412 heap->entry_evac();
413 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_evac)) return;
414
415 // Perform update-refs phase.
416 heap->vmop_entry_init_updaterefs();
417 heap->entry_updaterefs();
418 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_updaterefs)) return;
419
420 heap->vmop_entry_final_updaterefs();
421
422 // Update references freed up collection set, kick the cleanup to reclaim the space.
423 heap->entry_cleanup_complete();
424 }
425
426 // Cycle is complete
427 heap->heuristics()->record_success_concurrent();
428 heap->shenandoah_policy()->record_success_concurrent();
429 }
430
431 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point) {
432 ShenandoahHeap* heap = ShenandoahHeap::heap();
433 if (heap->cancelled_gc()) {
434 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting");
435 if (!in_graceful_shutdown()) {
436 assert (_degen_point == ShenandoahHeap::_degenerated_outside_cycle,
437 "Should not be set yet: %s", ShenandoahHeap::degen_point_to_string(_degen_point));
438 _degen_point = point;
439 }
440 return true;
441 }
442 return false;
443 }
444
445 void ShenandoahControlThread::stop_service() {
446 // Nothing to do here.
447 }
448
449 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) {
450 GCIdMark gc_id_mark;
451 ShenandoahGCSession session(cause);
452
453 ShenandoahHeap* heap = ShenandoahHeap::heap();
454 heap->vmop_entry_full(cause);
455
456 heap->heuristics()->record_success_full();
457 heap->shenandoah_policy()->record_success_full();
458 }
459
460 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point) {
461 assert (point != ShenandoahHeap::_degenerated_unset, "Degenerated point should be set");
462
463 GCIdMark gc_id_mark;
464 ShenandoahGCSession session(cause);
465
466 ShenandoahHeap* heap = ShenandoahHeap::heap();
467 heap->vmop_degenerated(point);
468
469 heap->heuristics()->record_success_degenerated();
470 heap->shenandoah_policy()->record_success_degenerated();
471 }
472
473 void ShenandoahControlThread::service_uncommit(double shrink_before) {
474 ShenandoahHeap* heap = ShenandoahHeap::heap();
475
476 // Determine if there is work to do. This avoids taking heap lock if there is
477 // no work available, avoids spamming logs with superfluous logging messages,
478 // and minimises the amount of work while locks are taken.
479
480 if (heap->committed() <= heap->min_capacity()) return;
481
482 bool has_work = false;
483 for (size_t i = 0; i < heap->num_regions(); i++) {
484 ShenandoahHeapRegion *r = heap->get_region(i);
485 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
486 has_work = true;
487 break;
488 }
489 }
490
491 if (has_work) {
492 heap->entry_uncommit(shrink_before);
493 }
494 }
495
496 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const {
497 return GCCause::is_user_requested_gc(cause) ||
498 GCCause::is_serviceability_requested_gc(cause);
499 }
500
501 void ShenandoahControlThread::request_gc(GCCause::Cause cause) {
502 assert(GCCause::is_user_requested_gc(cause) ||
503 GCCause::is_serviceability_requested_gc(cause) ||
504 cause == GCCause::_metadata_GC_clear_soft_refs ||
505 cause == GCCause::_full_gc_alot ||
506 cause == GCCause::_wb_full_gc ||
507 cause == GCCause::_scavenge_alot,
508 "only requested GCs here");
509
510 if (is_explicit_gc(cause)) {
511 if (!DisableExplicitGC) {
512 handle_requested_gc(cause);
513 }
514 } else {
515 handle_requested_gc(cause);
516 }
517 }
518
519 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) {
520 // Make sure we have at least one complete GC cycle before unblocking
521 // from the explicit GC request.
522 //
523 // This is especially important for weak references cleanup and/or native
524 // resources (e.g. DirectByteBuffers) machinery: when explicit GC request
525 // comes very late in the already running cycle, it would miss lots of new
526 // opportunities for cleanup that were made available before the caller
527 // requested the GC.
528
529 MonitorLocker ml(&_gc_waiters_lock);
530 size_t current_gc_id = get_gc_id();
531 size_t required_gc_id = current_gc_id + 1;
532 while (current_gc_id < required_gc_id) {
533 _gc_requested.set();
534 _requested_gc_cause = cause;
535 ml.wait();
536 current_gc_id = get_gc_id();
537 }
538 }
539
540 void ShenandoahControlThread::handle_alloc_failure(ShenandoahAllocRequest& req) {
541 ShenandoahHeap* heap = ShenandoahHeap::heap();
542
543 assert(current()->is_Java_thread(), "expect Java thread here");
544
545 if (try_set_alloc_failure_gc()) {
546 // Only report the first allocation failure
547 log_info(gc)("Failed to allocate %s, " SIZE_FORMAT "%s",
548 req.type_string(),
549 byte_size_in_proper_unit(req.size() * HeapWordSize), proper_unit_for_byte_size(req.size() * HeapWordSize));
550
551 // Now that alloc failure GC is scheduled, we can abort everything else
552 heap->cancel_gc(GCCause::_allocation_failure);
553 }
554
555 MonitorLocker ml(&_alloc_failure_waiters_lock);
556 while (is_alloc_failure_gc()) {
557 ml.wait();
558 }
559 }
560
561 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) {
562 ShenandoahHeap* heap = ShenandoahHeap::heap();
563
564 if (try_set_alloc_failure_gc()) {
565 // Only report the first allocation failure
566 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation",
567 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
568 }
569
570 // Forcefully report allocation failure
571 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac);
572 }
573
574 void ShenandoahControlThread::notify_alloc_failure_waiters() {
575 _alloc_failure_gc.unset();
576 MonitorLocker ml(&_alloc_failure_waiters_lock);
577 ml.notify_all();
578 }
579
580 bool ShenandoahControlThread::try_set_alloc_failure_gc() {
581 return _alloc_failure_gc.try_set();
582 }
583
584 bool ShenandoahControlThread::is_alloc_failure_gc() {
585 return _alloc_failure_gc.is_set();
586 }
587
588 void ShenandoahControlThread::notify_gc_waiters() {
589 _gc_requested.unset();
590 MonitorLocker ml(&_gc_waiters_lock);
591 ml.notify_all();
592 }
593
594 void ShenandoahControlThread::handle_counters_update() {
595 if (_do_counters_update.is_set()) {
596 _do_counters_update.unset();
597 ShenandoahHeap::heap()->monitoring_support()->update_counters();
598 }
599 }
600
601 void ShenandoahControlThread::handle_force_counters_update() {
602 if (_force_counters_update.is_set()) {
603 _do_counters_update.unset(); // reset these too, we do update now!
604 ShenandoahHeap::heap()->monitoring_support()->update_counters();
605 }
606 }
607
608 void ShenandoahControlThread::notify_heap_changed() {
609 // This is called from allocation path, and thus should be fast.
610
611 // Update monitoring counters when we took a new region. This amortizes the
612 // update costs on slow path.
613 if (_do_counters_update.is_unset()) {
614 _do_counters_update.set();
615 }
616 // Notify that something had changed.
617 if (_heap_changed.is_unset()) {
618 _heap_changed.set();
619 }
620 }
621
622 void ShenandoahControlThread::pacing_notify_alloc(size_t words) {
623 assert(ShenandoahPacing, "should only call when pacing is enabled");
624 Atomic::add(&_allocs_seen, words);
625 }
626
627 void ShenandoahControlThread::set_forced_counters_update(bool value) {
628 _force_counters_update.set_cond(value);
629 }
630
631 void ShenandoahControlThread::reset_gc_id() {
632 Atomic::store(&_gc_id, (size_t)0);
633 }
634
635 void ShenandoahControlThread::update_gc_id() {
636 Atomic::inc(&_gc_id);
637 }
638
639 size_t ShenandoahControlThread::get_gc_id() {
640 return Atomic::load(&_gc_id);
641 }
642
643 void ShenandoahControlThread::print() const {
644 print_on(tty);
645 }
646
647 void ShenandoahControlThread::print_on(outputStream* st) const {
648 st->print("Shenandoah Concurrent Thread");
649 Thread::print_on(st);
650 st->cr();
651 }
652
653 void ShenandoahControlThread::start() {
654 create_and_start();
655 }
656
657 void ShenandoahControlThread::prepare_for_graceful_shutdown() {
658 _graceful_shutdown.set();
659 }
660
661 bool ShenandoahControlThread::in_graceful_shutdown() {
662 return _graceful_shutdown.is_set();
663 }