1 /*
2 * Copyright (c) 2013, 2021, 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 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
27 #include "gc/shenandoah/shenandoahConcurrentGC.hpp"
28 #include "gc/shenandoah/shenandoahControlThread.hpp"
29 #include "gc/shenandoah/shenandoahDegeneratedGC.hpp"
30 #include "gc/shenandoah/shenandoahFreeSet.hpp"
31 #include "gc/shenandoah/shenandoahFullGC.hpp"
32 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
33 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
34 #include "gc/shenandoah/shenandoahMark.inline.hpp"
35 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
36 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
37 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
38 #include "gc/shenandoah/shenandoahUtils.hpp"
39 #include "gc/shenandoah/shenandoahVMOperations.hpp"
40 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
41 #include "gc/shenandoah/heuristics/shenandoahHeuristics.hpp"
42 #include "memory/iterator.hpp"
43 #include "memory/metaspaceUtils.hpp"
44 #include "memory/metaspaceStats.hpp"
45 #include "memory/universe.hpp"
46 #include "runtime/atomic.hpp"
47
48 ShenandoahControlThread::ShenandoahControlThread() :
49 ConcurrentGCThread(),
50 _alloc_failure_waiters_lock(Mutex::safepoint-1, "ShenandoahAllocFailureGC_lock", true),
51 _gc_waiters_lock(Mutex::safepoint-1, "ShenandoahRequestedGC_lock", true),
52 _periodic_task(this),
53 _requested_gc_cause(GCCause::_no_cause_specified),
54 _degen_point(ShenandoahGC::_degenerated_outside_cycle),
55 _allocs_seen(0) {
56
57 reset_gc_id();
58 create_and_start();
59 _periodic_task.enroll();
60 if (ShenandoahPacing) {
61 _periodic_pacer_notify_task.enroll();
62 }
63 }
64
65 ShenandoahControlThread::~ShenandoahControlThread() {
66 // This is here so that super is called.
67 }
68
69 void ShenandoahPeriodicTask::task() {
70 _thread->handle_force_counters_update();
71 _thread->handle_counters_update();
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 is_gc_requested = _gc_requested.is_set();
101 GCCause::Cause requested_gc_cause = _requested_gc_cause;
102 bool explicit_gc_requested = is_gc_requested && is_explicit_gc(requested_gc_cause);
103 bool implicit_gc_requested = is_gc_requested && !is_explicit_gc(requested_gc_cause);
104
105 // This control loop iteration have seen this much allocations.
106 size_t allocs_seen = Atomic::xchg(&_allocs_seen, (size_t)0, memory_order_relaxed);
107
108 // Check if we have seen a new target for soft max heap size.
109 bool soft_max_changed = check_soft_max_changed();
110
111 // Choose which GC mode to run in. The block below should select a single mode.
112 GCMode mode = none;
113 GCCause::Cause cause = GCCause::_last_gc_cause;
114 ShenandoahGC::ShenandoahDegenPoint degen_point = ShenandoahGC::_degenerated_unset;
115
116 if (alloc_failure_pending) {
117 // Allocation failure takes precedence: we have to deal with it first thing
118 log_info(gc)("Trigger: Handle Allocation Failure");
119
120 cause = GCCause::_allocation_failure;
121
122 // Consume the degen point, and seed it with default value
123 degen_point = _degen_point;
124 _degen_point = ShenandoahGC::_degenerated_outside_cycle;
125
126 if (ShenandoahDegeneratedGC && heuristics->should_degenerate_cycle()) {
127 heuristics->record_allocation_failure_gc();
128 policy->record_alloc_failure_to_degenerated(degen_point);
129 mode = stw_degenerated;
130 } else {
131 heuristics->record_allocation_failure_gc();
132 policy->record_alloc_failure_to_full();
133 mode = stw_full;
134 }
135
136 } else if (explicit_gc_requested) {
137 cause = requested_gc_cause;
138 log_info(gc)("Trigger: Explicit GC request (%s)", GCCause::to_string(cause));
139
140 heuristics->record_requested_gc();
141
142 if (ExplicitGCInvokesConcurrent) {
143 policy->record_explicit_to_concurrent();
144 mode = default_mode;
145 // Unload and clean up everything
146 heap->set_unload_classes(heuristics->can_unload_classes());
147 } else {
148 policy->record_explicit_to_full();
149 mode = stw_full;
150 }
151 } else if (implicit_gc_requested) {
152 cause = requested_gc_cause;
153 log_info(gc)("Trigger: Implicit GC request (%s)", GCCause::to_string(cause));
154
155 heuristics->record_requested_gc();
156
157 if (ShenandoahImplicitGCInvokesConcurrent) {
158 policy->record_implicit_to_concurrent();
159 mode = default_mode;
160
161 // Unload and clean up everything
162 heap->set_unload_classes(heuristics->can_unload_classes());
163 } else {
164 policy->record_implicit_to_full();
165 mode = stw_full;
166 }
167 } else {
168 // Potential normal cycle: ask heuristics if it wants to act
169 if (heuristics->should_start_gc()) {
170 mode = default_mode;
171 cause = default_cause;
172 }
173
174 // Ask policy if this cycle wants to process references or unload classes
175 heap->set_unload_classes(heuristics->should_unload_classes());
176 }
177
178 // Blow all soft references on this cycle, if handling allocation failure,
179 // either implicit or explicit GC request, or we are requested to do so unconditionally.
180 if (alloc_failure_pending || implicit_gc_requested || explicit_gc_requested || ShenandoahAlwaysClearSoftRefs) {
181 heap->soft_ref_policy()->set_should_clear_all_soft_refs(true);
182 }
183
184 bool gc_requested = (mode != none);
185 assert (!gc_requested || cause != GCCause::_last_gc_cause, "GC cause should be set");
186
187 if (gc_requested) {
188 // GC is starting, bump the internal ID
189 update_gc_id();
190
191 heap->reset_bytes_allocated_since_gc_start();
192
193 MetaspaceCombinedStats meta_sizes = MetaspaceUtils::get_combined_statistics();
194
195 // If GC was requested, we are sampling the counters even without actual triggers
196 // from allocation machinery. This captures GC phases more accurately.
197 set_forced_counters_update(true);
198
199 // If GC was requested, we better dump freeset data for performance debugging
200 {
201 ShenandoahHeapLocker locker(heap->lock());
202 heap->free_set()->log_status();
203 }
204
205 switch (mode) {
206 case concurrent_normal:
207 service_concurrent_normal_cycle(cause);
208 break;
209 case stw_degenerated:
210 service_stw_degenerated_cycle(cause, degen_point);
211 break;
212 case stw_full:
213 service_stw_full_cycle(cause);
214 break;
215 default:
216 ShouldNotReachHere();
217 }
218
219 // If this was the requested GC cycle, notify waiters about it
220 if (explicit_gc_requested || implicit_gc_requested) {
221 notify_gc_waiters();
222 }
223
224 // If this was the allocation failure GC cycle, notify waiters about it
225 if (alloc_failure_pending) {
226 notify_alloc_failure_waiters();
227 }
228
229 // Report current free set state at the end of cycle, whether
230 // it is a normal completion, or the abort.
231 {
232 ShenandoahHeapLocker locker(heap->lock());
233 heap->free_set()->log_status();
234
235 // Notify Universe about new heap usage. This has implications for
236 // global soft refs policy, and we better report it every time heap
237 // usage goes down.
238 Universe::heap()->update_capacity_and_used_at_gc();
239
240 // Signal that we have completed a visit to all live objects.
241 Universe::heap()->record_whole_heap_examined_timestamp();
242 }
243
244 // Disable forced counters update, and update counters one more time
245 // to capture the state at the end of GC session.
246 handle_force_counters_update();
247 set_forced_counters_update(false);
248
249 // Retract forceful part of soft refs policy
250 heap->soft_ref_policy()->set_should_clear_all_soft_refs(false);
251
252 // Clear metaspace oom flag, if current cycle unloaded classes
253 if (heap->unload_classes()) {
254 heuristics->clear_metaspace_oom();
255 }
256
257 // Commit worker statistics to cycle data
258 heap->phase_timings()->flush_par_workers_to_cycle();
259 if (ShenandoahPacing) {
260 heap->pacer()->flush_stats_to_cycle();
261 }
262
263 // Print GC stats for current cycle
264 {
265 LogTarget(Info, gc, stats) lt;
266 if (lt.is_enabled()) {
267 ResourceMark rm;
268 LogStream ls(lt);
269 heap->phase_timings()->print_cycle_on(&ls);
270 if (ShenandoahPacing) {
271 heap->pacer()->print_cycle_on(&ls);
272 }
273 }
274 }
275
276 // Commit statistics to globals
277 heap->phase_timings()->flush_cycle_to_global();
278
279 // Print Metaspace change following GC (if logging is enabled).
280 MetaspaceUtils::print_metaspace_change(meta_sizes);
281
282 // GC is over, we are at idle now
283 if (ShenandoahPacing) {
284 heap->pacer()->setup_for_idle();
285 }
286 } else {
287 // Allow allocators to know we have seen this much regions
288 if (ShenandoahPacing && (allocs_seen > 0)) {
289 heap->pacer()->report_alloc(allocs_seen);
290 }
291 }
292
293 double current = os::elapsedTime();
294
295 if (ShenandoahUncommit && (explicit_gc_requested || soft_max_changed || (current - last_shrink_time > shrink_period))) {
296 // Explicit GC tries to uncommit everything down to min capacity.
297 // Soft max change tries to uncommit everything down to target capacity.
298 // Periodic uncommit tries to uncommit suitable regions down to min capacity.
299
300 double shrink_before = (explicit_gc_requested || soft_max_changed) ?
301 current :
302 current - (ShenandoahUncommitDelay / 1000.0);
303
304 size_t shrink_until = soft_max_changed ?
305 heap->soft_max_capacity() :
306 heap->min_capacity();
307
308 service_uncommit(shrink_before, shrink_until);
309 heap->phase_timings()->flush_cycle_to_global();
310 last_shrink_time = current;
311 }
312
313 // Wait before performing the next action. If allocation happened during this wait,
314 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle,
315 // back off exponentially.
316 if (_heap_changed.try_unset()) {
317 sleep = ShenandoahControlIntervalMin;
318 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){
319 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2));
320 last_sleep_adjust_time = current;
321 }
322 os::naked_short_sleep(sleep);
323 }
324
325 // Wait for the actual stop(), can't leave run_service() earlier.
326 while (!should_terminate()) {
327 os::naked_short_sleep(ShenandoahControlIntervalMin);
328 }
329 }
330
331 bool ShenandoahControlThread::check_soft_max_changed() const {
332 ShenandoahHeap* heap = ShenandoahHeap::heap();
333 size_t new_soft_max = Atomic::load(&SoftMaxHeapSize);
334 size_t old_soft_max = heap->soft_max_capacity();
335 if (new_soft_max != old_soft_max) {
336 new_soft_max = MAX2(heap->min_capacity(), new_soft_max);
337 new_soft_max = MIN2(heap->max_capacity(), new_soft_max);
338 if (new_soft_max != old_soft_max) {
339 log_info(gc)("Soft Max Heap Size: " SIZE_FORMAT "%s -> " SIZE_FORMAT "%s",
340 byte_size_in_proper_unit(old_soft_max), proper_unit_for_byte_size(old_soft_max),
341 byte_size_in_proper_unit(new_soft_max), proper_unit_for_byte_size(new_soft_max)
342 );
343 heap->set_soft_max_capacity(new_soft_max);
344 return true;
345 }
346 }
347 return false;
348 }
349
350 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) {
351 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during
352 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there.
353 // If second allocation failure happens during Degenerated GC cycle (for example, when GC
354 // tries to evac something and no memory is available), cycle degrades to Full GC.
355 //
356 // There are also a shortcut through the normal cycle: immediate garbage shortcut, when
357 // heuristics says there are no regions to compact, and all the collection comes from immediately
358 // reclaimable regions.
359 //
360 // ................................................................................................
361 //
362 // (immediate garbage shortcut) Concurrent GC
363 // /-------------------------------------------\
364 // | |
365 // | |
366 // | |
367 // | v
368 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END]
369 // | | | ^
370 // | (af) | (af) | (af) |
371 // ..................|....................|.................|..............|.......................
372 // | | | |
373 // | | | | Degenerated GC
374 // v v v |
375 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o
376 // | | | ^
377 // | (af) | (af) | (af) |
378 // ..................|....................|.................|..............|.......................
379 // | | | |
380 // | v | | Full GC
381 // \------------------->o<----------------/ |
382 // | |
383 // v |
384 // Full GC --------------------------/
385 //
386 ShenandoahHeap* heap = ShenandoahHeap::heap();
387 if (check_cancellation_or_degen(ShenandoahGC::_degenerated_outside_cycle)) return;
388
389 GCIdMark gc_id_mark;
390 ShenandoahGCSession session(cause);
391
392 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
393
394 ShenandoahConcurrentGC gc;
395 if (gc.collect(cause)) {
396 // Cycle is complete
397 heap->heuristics()->record_success_concurrent();
398 heap->shenandoah_policy()->record_success_concurrent();
399 } else {
400 assert(heap->cancelled_gc(), "Must have been cancelled");
401 check_cancellation_or_degen(gc.degen_point());
402 }
403 }
404
405 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahGC::ShenandoahDegenPoint point) {
406 ShenandoahHeap* heap = ShenandoahHeap::heap();
407 if (heap->cancelled_gc()) {
408 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting");
409 if (!in_graceful_shutdown()) {
410 assert (_degen_point == ShenandoahGC::_degenerated_outside_cycle,
411 "Should not be set yet: %s", ShenandoahGC::degen_point_to_string(_degen_point));
412 _degen_point = point;
413 }
414 return true;
415 }
416 return false;
417 }
418
419 void ShenandoahControlThread::stop_service() {
420 // Nothing to do here.
421 }
422
423 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) {
424 GCIdMark gc_id_mark;
425 ShenandoahGCSession session(cause);
426
427 ShenandoahFullGC gc;
428 gc.collect(cause);
429
430 ShenandoahHeap* const heap = ShenandoahHeap::heap();
431 heap->heuristics()->record_success_full();
432 heap->shenandoah_policy()->record_success_full();
433 }
434
435 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahGC::ShenandoahDegenPoint point) {
436 assert (point != ShenandoahGC::_degenerated_unset, "Degenerated point should be set");
437
438 GCIdMark gc_id_mark;
439 ShenandoahGCSession session(cause);
440
441 ShenandoahDegenGC gc(point);
442 gc.collect(cause);
443
444 ShenandoahHeap* const heap = ShenandoahHeap::heap();
445 heap->heuristics()->record_success_degenerated();
446 heap->shenandoah_policy()->record_success_degenerated();
447 }
448
449 void ShenandoahControlThread::service_uncommit(double shrink_before, size_t shrink_until) {
450 ShenandoahHeap* heap = ShenandoahHeap::heap();
451
452 // Determine if there is work to do. This avoids taking heap lock if there is
453 // no work available, avoids spamming logs with superfluous logging messages,
454 // and minimises the amount of work while locks are taken.
455
456 if (heap->committed() <= shrink_until) return;
457
458 bool has_work = false;
459 for (size_t i = 0; i < heap->num_regions(); i++) {
460 ShenandoahHeapRegion *r = heap->get_region(i);
461 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
462 has_work = true;
463 break;
464 }
465 }
466
467 if (has_work) {
468 heap->entry_uncommit(shrink_before, shrink_until);
469 }
470 }
471
472 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const {
473 return GCCause::is_user_requested_gc(cause) ||
474 GCCause::is_serviceability_requested_gc(cause);
475 }
476
477 void ShenandoahControlThread::request_gc(GCCause::Cause cause) {
478 assert(GCCause::is_user_requested_gc(cause) ||
479 GCCause::is_serviceability_requested_gc(cause) ||
480 cause == GCCause::_metadata_GC_clear_soft_refs ||
481 cause == GCCause::_full_gc_alot ||
482 cause == GCCause::_wb_full_gc ||
483 cause == GCCause::_wb_breakpoint ||
484 cause == GCCause::_scavenge_alot,
485 "only requested GCs here");
486
487 if (is_explicit_gc(cause)) {
488 if (!DisableExplicitGC) {
489 handle_requested_gc(cause);
490 }
491 } else {
492 handle_requested_gc(cause);
493 }
494 }
495
496 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) {
497 // Make sure we have at least one complete GC cycle before unblocking
498 // from the explicit GC request.
499 //
500 // This is especially important for weak references cleanup and/or native
501 // resources (e.g. DirectByteBuffers) machinery: when explicit GC request
502 // comes very late in the already running cycle, it would miss lots of new
503 // opportunities for cleanup that were made available before the caller
504 // requested the GC.
505
506 MonitorLocker ml(&_gc_waiters_lock);
507 size_t current_gc_id = get_gc_id();
508 size_t required_gc_id = current_gc_id + 1;
509 while (current_gc_id < required_gc_id) {
510 // Although setting gc request is under _gc_waiters_lock, but read side (run_service())
511 // does not take the lock. We need to enforce following order, so that read side sees
512 // latest requested gc cause when the flag is set.
513 _requested_gc_cause = cause;
514 _gc_requested.set();
515
516 if (cause != GCCause::_wb_breakpoint) {
517 ml.wait();
518 }
519 current_gc_id = get_gc_id();
520 }
521 }
522
523 void ShenandoahControlThread::handle_alloc_failure(ShenandoahAllocRequest& req) {
524 ShenandoahHeap* heap = ShenandoahHeap::heap();
525
526 assert(current()->is_Java_thread(), "expect Java thread here");
527
528 if (try_set_alloc_failure_gc()) {
529 // Only report the first allocation failure
530 log_info(gc)("Failed to allocate %s, " SIZE_FORMAT "%s",
531 req.type_string(),
532 byte_size_in_proper_unit(req.size() * HeapWordSize), proper_unit_for_byte_size(req.size() * HeapWordSize));
533
534 // Now that alloc failure GC is scheduled, we can abort everything else
535 heap->cancel_gc(GCCause::_allocation_failure);
536 }
537
538 MonitorLocker ml(&_alloc_failure_waiters_lock);
539 while (is_alloc_failure_gc()) {
540 ml.wait();
541 }
542 }
543
544 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) {
545 ShenandoahHeap* heap = ShenandoahHeap::heap();
546
547 if (try_set_alloc_failure_gc()) {
548 // Only report the first allocation failure
549 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation",
550 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
551 }
552
553 // Forcefully report allocation failure
554 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac);
555 }
556
557 void ShenandoahControlThread::notify_alloc_failure_waiters() {
558 _alloc_failure_gc.unset();
559 MonitorLocker ml(&_alloc_failure_waiters_lock);
560 ml.notify_all();
561 }
562
563 bool ShenandoahControlThread::try_set_alloc_failure_gc() {
564 return _alloc_failure_gc.try_set();
565 }
566
567 bool ShenandoahControlThread::is_alloc_failure_gc() {
568 return _alloc_failure_gc.is_set();
569 }
570
571 void ShenandoahControlThread::notify_gc_waiters() {
572 _gc_requested.unset();
573 MonitorLocker ml(&_gc_waiters_lock);
574 ml.notify_all();
575 }
576
577 void ShenandoahControlThread::handle_counters_update() {
578 if (_do_counters_update.is_set()) {
579 _do_counters_update.unset();
580 ShenandoahHeap::heap()->monitoring_support()->update_counters();
581 }
582 }
583
584 void ShenandoahControlThread::handle_force_counters_update() {
585 if (_force_counters_update.is_set()) {
586 _do_counters_update.unset(); // reset these too, we do update now!
587 ShenandoahHeap::heap()->monitoring_support()->update_counters();
588 }
589 }
590
591 void ShenandoahControlThread::notify_heap_changed() {
592 // This is called from allocation path, and thus should be fast.
593
594 // Update monitoring counters when we took a new region. This amortizes the
595 // update costs on slow path.
596 if (_do_counters_update.is_unset()) {
597 _do_counters_update.set();
598 }
599 // Notify that something had changed.
600 if (_heap_changed.is_unset()) {
601 _heap_changed.set();
602 }
603 }
604
605 void ShenandoahControlThread::pacing_notify_alloc(size_t words) {
606 assert(ShenandoahPacing, "should only call when pacing is enabled");
607 Atomic::add(&_allocs_seen, words, memory_order_relaxed);
608 }
609
610 void ShenandoahControlThread::set_forced_counters_update(bool value) {
611 _force_counters_update.set_cond(value);
612 }
613
614 void ShenandoahControlThread::reset_gc_id() {
615 Atomic::store(&_gc_id, (size_t)0);
616 }
617
618 void ShenandoahControlThread::update_gc_id() {
619 Atomic::inc(&_gc_id);
620 }
621
622 size_t ShenandoahControlThread::get_gc_id() {
623 return Atomic::load(&_gc_id);
624 }
625
626 void ShenandoahControlThread::print() const {
627 print_on(tty);
628 }
629
630 void ShenandoahControlThread::print_on(outputStream* st) const {
631 st->print("Shenandoah Concurrent Thread");
632 Thread::print_on(st);
633 st->cr();
634 }
635
636 void ShenandoahControlThread::start() {
637 create_and_start();
638 }
639
640 void ShenandoahControlThread::prepare_for_graceful_shutdown() {
641 _graceful_shutdown.set();
642 }
643
644 bool ShenandoahControlThread::in_graceful_shutdown() {
645 return _graceful_shutdown.is_set();
646 }