1 /*
2 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25
26 #include "gc_implementation/shared/gcTimer.hpp"
27 #include "gc_implementation/shenandoah/shenandoahGCTraceTime.hpp"
28 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.inline.hpp"
29 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp"
30 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp"
31 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp"
32 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc_implementation/shenandoah/shenandoahHeuristics.hpp"
34 #include "gc_implementation/shenandoah/shenandoahMonitoringSupport.hpp"
35 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
36 #include "gc_implementation/shenandoah/shenandoahTraversalGC.hpp"
37 #include "gc_implementation/shenandoah/shenandoahUtils.hpp"
38 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp"
39 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp"
40 #include "memory/iterator.hpp"
41 #include "memory/universe.hpp"
42
43 #ifdef _WINDOWS
44 #pragma warning(disable : 4355)
45 #endif
46
47 SurrogateLockerThread* ShenandoahControlThread::_slt = NULL;
48
49 ShenandoahControlThread::ShenandoahControlThread() :
50 ConcurrentGCThread(),
51 _alloc_failure_waiters_lock(Mutex::leaf, "ShenandoahAllocFailureGC_lock", true),
52 _gc_waiters_lock(Mutex::leaf, "ShenandoahRequestedGC_lock", true),
53 _periodic_task(this),
54 _requested_gc_cause(GCCause::_no_cause_specified),
55 _degen_point(ShenandoahHeap::_degenerated_outside_cycle),
56 _allocs_seen(0) {
57
58 if (os::create_thread(this, os::cgc_thread)) {
59 int native_prio;
60 if (ShenandoahCriticalControlThreadPriority) {
61 native_prio = os::java_to_os_priority[CriticalPriority];
62 } else {
63 native_prio = os::java_to_os_priority[NearMaxPriority];
64 }
65 os::set_native_priority(this, native_prio);
66 if (!_should_terminate && !DisableStartThread) {
67 os::start_thread(this);
68 }
69 }
70
71 _periodic_task.enroll();
72 _periodic_satb_flush_task.enroll();
73 }
74
75 ShenandoahControlThread::~ShenandoahControlThread() {
76 // This is here so that super is called.
77 }
78
79 void ShenandoahPeriodicTask::task() {
80 _thread->handle_force_counters_update();
81 _thread->handle_counters_update();
82 }
83
84 void ShenandoahPeriodicSATBFlushTask::task() {
85 ShenandoahHeap::heap()->force_satb_flush_all_threads();
86 }
87
88 void ShenandoahControlThread::run() {
89 initialize_in_thread();
90
91 wait_for_universe_init();
92
93 // Wait until we have the surrogate locker thread in place.
94 {
95 MutexLockerEx x(CGC_lock, true);
96 while(_slt == NULL && !_should_terminate) {
97 CGC_lock->wait(true, 200);
98 }
99 }
100
101 ShenandoahHeap* heap = ShenandoahHeap::heap();
102
103 GCMode default_mode = heap->is_traversal_mode() ?
104 concurrent_traversal : concurrent_normal;
105 GCCause::Cause default_cause = heap->is_traversal_mode() ?
106 GCCause::_shenandoah_traversal_gc : GCCause::_shenandoah_concurrent_gc;
107 int sleep = ShenandoahControlIntervalMin;
108
109 double last_shrink_time = os::elapsedTime();
110 double last_sleep_adjust_time = os::elapsedTime();
111
112 // Shrink period avoids constantly polling regions for shrinking.
113 // Having a period 10x lower than the delay would mean we hit the
114 // shrinking with lag of less than 1/10-th of true delay.
115 // ShenandoahUncommitDelay is in msecs, but shrink_period is in seconds.
116 double shrink_period = (double)ShenandoahUncommitDelay / 1000 / 10;
117
118 ShenandoahCollectorPolicy* policy = heap->shenandoah_policy();
119
120 ShenandoahHeuristics* heuristics = heap->heuristics();
121 while (!in_graceful_shutdown() && !_should_terminate) {
122 // Figure out if we have pending requests.
123 bool alloc_failure_pending = _alloc_failure_gc.is_set();
124 bool explicit_gc_requested = _gc_requested.is_set() && is_explicit_gc(_requested_gc_cause);
125 bool implicit_gc_requested = _gc_requested.is_set() && !is_explicit_gc(_requested_gc_cause);
126
127 // This control loop iteration have seen this much allocations.
128 intptr_t allocs_seen = (intptr_t)(Atomic::xchg_ptr(0, &_allocs_seen));
129
130 // Choose which GC mode to run in. The block below should select a single mode.
131 GCMode mode = none;
132 GCCause::Cause cause = GCCause::_last_gc_cause;
133 ShenandoahHeap::ShenandoahDegenPoint degen_point = ShenandoahHeap::_degenerated_unset;
134
135 if (alloc_failure_pending) {
136 // Allocation failure takes precedence: we have to deal with it first thing
137 log_info(gc)("Trigger: Handle Allocation Failure");
138
139 cause = GCCause::_allocation_failure;
140
141 // Consume the degen point, and seed it with default value
142 degen_point = _degen_point;
143 _degen_point = ShenandoahHeap::_degenerated_outside_cycle;
144
145 if (ShenandoahDegeneratedGC && heuristics->should_degenerate_cycle()) {
146 heuristics->record_allocation_failure_gc();
147 policy->record_alloc_failure_to_degenerated(degen_point);
148 mode = stw_degenerated;
149 } else {
150 heuristics->record_allocation_failure_gc();
151 policy->record_alloc_failure_to_full();
152 mode = stw_full;
153 }
154
155 } else if (explicit_gc_requested) {
156 cause = _requested_gc_cause;
157 log_info(gc)("Trigger: Explicit GC request (%s)", GCCause::to_string(cause));
158
159 heuristics->record_requested_gc();
160
161 if (ExplicitGCInvokesConcurrent) {
162 policy->record_explicit_to_concurrent();
163 mode = default_mode;
164 // Unload and clean up everything
165 heap->set_process_references(heuristics->can_process_references());
166 heap->set_unload_classes(heuristics->can_unload_classes());
167 } else {
168 policy->record_explicit_to_full();
169 mode = stw_full;
170 }
171 } else if (implicit_gc_requested) {
172 cause = _requested_gc_cause;
173 log_info(gc)("Trigger: Implicit GC request (%s)", GCCause::to_string(cause));
174
175 heuristics->record_requested_gc();
176
177 if (ShenandoahImplicitGCInvokesConcurrent) {
178 policy->record_implicit_to_concurrent();
179 mode = default_mode;
180
181 // Unload and clean up everything
182 heap->set_process_references(heuristics->can_process_references());
183 heap->set_unload_classes(heuristics->can_unload_classes());
184 } else {
185 policy->record_implicit_to_full();
186 mode = stw_full;
187 }
188 } else {
189 // Potential normal cycle: ask heuristics if it wants to act
190 if (heuristics->should_start_gc()) {
191 mode = default_mode;
192 cause = default_cause;
193 }
194
195 // Ask policy if this cycle wants to process references or unload classes
196 heap->set_process_references(heuristics->should_process_references());
197 heap->set_unload_classes(heuristics->should_unload_classes());
198 }
199
200 // Blow all soft references on this cycle, if handling allocation failure,
201 // or we are requested to do so unconditionally.
202 if (alloc_failure_pending || ShenandoahAlwaysClearSoftRefs) {
203 heap->collector_policy()->set_should_clear_all_soft_refs(true);
204 }
205
206 bool gc_requested = (mode != none);
207 assert (!gc_requested || cause != GCCause::_last_gc_cause, "GC cause should be set");
208
209 if (gc_requested) {
210 heap->reset_bytes_allocated_since_gc_start();
211
212 // If GC was requested, we are sampling the counters even without actual triggers
213 // from allocation machinery. This captures GC phases more accurately.
214 set_forced_counters_update(true);
215
216 // If GC was requested, we better dump freeset data for performance debugging
217 {
218 ShenandoahHeapLocker locker(heap->lock());
219 heap->free_set()->log_status();
220 }
221 }
222
223 switch (mode) {
224 case none:
225 break;
226 case concurrent_traversal:
227 service_concurrent_traversal_cycle(cause);
228 break;
229 case concurrent_normal:
230 service_concurrent_normal_cycle(cause);
231 break;
232 case stw_degenerated:
233 service_stw_degenerated_cycle(cause, degen_point);
234 break;
235 case stw_full:
236 service_stw_full_cycle(cause);
237 break;
238 default:
239 ShouldNotReachHere();
240 }
241
242 if (gc_requested) {
243 // If this was the requested GC cycle, notify waiters about it
244 if (explicit_gc_requested || implicit_gc_requested) {
245 notify_gc_waiters();
246 }
247
248 // If this was the allocation failure GC cycle, notify waiters about it
249 if (alloc_failure_pending) {
250 notify_alloc_failure_waiters();
251 }
252
253 // Report current free set state at the end of cycle, whether
254 // it is a normal completion, or the abort.
255 {
256 ShenandoahHeapLocker locker(heap->lock());
257 heap->free_set()->log_status();
258
259 // Notify Universe about new heap usage. This has implications for
260 // global soft refs policy, and we better report it every time heap
261 // usage goes down.
262 Universe::update_heap_info_at_gc();
263 }
264
265 // Disable forced counters update, and update counters one more time
266 // to capture the state at the end of GC session.
267 handle_force_counters_update();
268 set_forced_counters_update(false);
269
270 // Retract forceful part of soft refs policy
271 heap->collector_policy()->set_should_clear_all_soft_refs(false);
272
273 // Clear metaspace oom flag, if current cycle unloaded classes
274 if (heap->unload_classes()) {
275 heuristics->clear_metaspace_oom();
276 }
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 last_shrink_time = current;
299 }
300
301 // Wait before performing the next action. If allocation happened during this wait,
302 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle,
303 // back off exponentially.
304 if (_heap_changed.try_unset()) {
305 sleep = ShenandoahControlIntervalMin;
306 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){
307 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2));
308 last_sleep_adjust_time = current;
309 }
310 os::naked_short_sleep(sleep);
311 }
312
313 // Wait for the actual stop(), can't leave run_service() earlier.
314 while (! _should_terminate) {
315 os::naked_short_sleep(ShenandoahControlIntervalMin);
316 }
317 terminate();
318 }
319
320 void ShenandoahControlThread::service_concurrent_traversal_cycle(GCCause::Cause cause) {
321 ShenandoahGCSession session(cause);
322
323 ShenandoahHeap* heap = ShenandoahHeap::heap();
324 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
325
326 // Reset for upcoming cycle
327 heap->entry_reset();
328
329 heap->vmop_entry_init_traversal();
330
331 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_traversal)) return;
332
333 heap->entry_traversal();
334 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_traversal)) return;
335
336 heap->vmop_entry_final_traversal();
337
338 heap->entry_cleanup();
339
340 heap->heuristics()->record_success_concurrent();
341 heap->shenandoah_policy()->record_success_concurrent();
342 }
343
344 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) {
345 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during
346 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there.
347 // If second allocation failure happens during Degenerated GC cycle (for example, when GC
348 // tries to evac something and no memory is available), cycle degrades to Full GC.
349 //
350 // There are also two shortcuts through the normal cycle: a) immediate garbage shortcut, when
351 // heuristics says there are no regions to compact, and all the collection comes from immediately
352 // reclaimable regions; b) coalesced UR shortcut, when heuristics decides to coalesce UR with the
353 // mark from the next cycle.
354 //
355 // ................................................................................................
356 //
357 // (immediate garbage shortcut) Concurrent GC
358 // /-------------------------------------------\
359 // | (coalesced UR) v
360 // | /----------------------->o
361 // | | |
362 // | | v
363 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END]
364 // | | | ^
365 // | (af) | (af) | (af) |
366 // ..................|....................|.................|..............|.......................
367 // | | | |
368 // | | | | Degenerated GC
369 // v v v |
370 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o
371 // | | | ^
372 // | (af) | (af) | (af) |
373 // ..................|....................|.................|..............|.......................
374 // | | | |
375 // | v | | Full GC
376 // \------------------->o<----------------/ |
377 // | |
378 // v |
379 // Full GC --------------------------/
380 //
381
382 ShenandoahHeap* heap = ShenandoahHeap::heap();
383
384 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_outside_cycle)) return;
385
386 ShenandoahGCSession session(cause);
387
388 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
389
390 // Reset for upcoming marking
391 heap->entry_reset();
392
393 // Start initial mark under STW
394 heap->vmop_entry_init_mark();
395
396 // Continue concurrent mark
397 heap->entry_mark();
398 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_mark)) return;
399
400 // If not cancelled, can try to concurrently pre-clean
401 heap->entry_preclean();
402
403 // Complete marking under STW, and start evacuation
404 heap->vmop_entry_final_mark();
405
406 // Final mark might have reclaimed some immediate garbage, kick cleanup to reclaim
407 // the space. This would be the last action if there is nothing to evacuate.
408 heap->entry_cleanup();
409
410 {
411 ShenandoahHeapLocker locker(heap->lock());
412 heap->free_set()->log_status();
413 }
414
415 // Continue the cycle with evacuation and optional update-refs.
416 // This may be skipped if there is nothing to evacuate.
417 // If so, evac_in_progress would be unset by collection set preparation code.
418 if (heap->is_evacuation_in_progress()) {
419 // Concurrently evacuate
420 heap->entry_evac();
421 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_evac)) return;
422
423 // Perform update-refs phase, if required. This phase can be skipped if heuristics
424 // decides to piggy-back the update-refs on the next marking cycle. On either path,
425 // we need to turn off evacuation: either in init-update-refs, or in final-evac.
426 if (heap->heuristics()->should_start_update_refs()) {
427 heap->vmop_entry_init_updaterefs();
428 heap->entry_updaterefs();
429 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_updaterefs)) return;
430
431 heap->vmop_entry_final_updaterefs();
432
433 // Update references freed up collection set, kick the cleanup to reclaim the space.
434 heap->entry_cleanup();
435
436 } else {
437 heap->vmop_entry_final_evac();
438 }
439 }
440
441 // Cycle is complete
442 heap->heuristics()->record_success_concurrent();
443 heap->shenandoah_policy()->record_success_concurrent();
444 }
445
446 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point) {
447 ShenandoahHeap* heap = ShenandoahHeap::heap();
448 if (heap->cancelled_gc()) {
449 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting");
450 if (!in_graceful_shutdown()) {
451 assert (_degen_point == ShenandoahHeap::_degenerated_outside_cycle,
452 err_msg("Should not be set yet: %s", ShenandoahHeap::degen_point_to_string(_degen_point)));
453 _degen_point = point;
454 }
455 return true;
456 }
457 return false;
458 }
459
460 void ShenandoahControlThread::stop() {
461 {
462 MutexLockerEx ml(Terminator_lock);
463 _should_terminate = true;
464 }
465
466 {
467 MutexLockerEx ml(CGC_lock, Mutex::_no_safepoint_check_flag);
468 CGC_lock->notify_all();
469 }
470
471 {
472 MutexLockerEx ml(Terminator_lock);
473 while (!_has_terminated) {
474 Terminator_lock->wait();
475 }
476 }
477 }
478
479 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) {
480 ShenandoahHeap* heap = ShenandoahHeap::heap();
481 ShenandoahGCSession session(cause);
482
483 heap->vmop_entry_full(cause);
484
485 heap->heuristics()->record_success_full();
486 heap->shenandoah_policy()->record_success_full();
487 }
488
489 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point) {
490 assert (point != ShenandoahHeap::_degenerated_unset, "Degenerated point should be set");
491 ShenandoahHeap* heap = ShenandoahHeap::heap();
492 ShenandoahGCSession session(cause);
493
494 heap->vmop_degenerated(point);
495
496 heap->heuristics()->record_success_degenerated();
497 heap->shenandoah_policy()->record_success_degenerated();
498 }
499
500 void ShenandoahControlThread::service_uncommit(double shrink_before) {
501 ShenandoahHeap* heap = ShenandoahHeap::heap();
502
503 // Determine if there is work to do. This avoids taking heap lock if there is
504 // no work available, avoids spamming logs with superfluous logging messages,
505 // and minimises the amount of work while locks are taken.
506
507 if (heap->committed() <= heap->min_capacity()) return;
508
509 bool has_work = false;
510 for (size_t i = 0; i < heap->num_regions(); i++) {
511 ShenandoahHeapRegion *r = heap->get_region(i);
512 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
513 has_work = true;
514 break;
515 }
516 }
517
518 if (has_work) {
519 heap->entry_uncommit(shrink_before);
520 }
521 }
522
523 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const {
524 return GCCause::is_user_requested_gc(cause) ||
525 GCCause::is_serviceability_requested_gc(cause);
526 }
527
528 void ShenandoahControlThread::request_gc(GCCause::Cause cause) {
529 assert(GCCause::is_user_requested_gc(cause) ||
530 GCCause::is_serviceability_requested_gc(cause) ||
531 cause == GCCause::_shenandoah_metadata_gc_clear_softrefs ||
532 cause == GCCause::_full_gc_alot ||
533 cause == GCCause::_scavenge_alot,
534 "only requested GCs here");
535
536 if (is_explicit_gc(cause)) {
537 if (!DisableExplicitGC) {
538 handle_requested_gc(cause);
539 }
540 } else {
541 handle_requested_gc(cause);
542 }
543 }
544
545 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) {
546 _requested_gc_cause = cause;
547 _gc_requested.set();
548 MonitorLockerEx ml(&_gc_waiters_lock);
549 while (_gc_requested.is_set()) {
550 ml.wait();
551 }
552 }
553
554 void ShenandoahControlThread::handle_alloc_failure(size_t words) {
555 ShenandoahHeap* heap = ShenandoahHeap::heap();
556
557 assert(current()->is_Java_thread(), "expect Java thread here");
558
559 if (try_set_alloc_failure_gc()) {
560 // Only report the first allocation failure
561 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s",
562 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
563
564 // Now that alloc failure GC is scheduled, we can abort everything else
565 heap->cancel_gc(GCCause::_allocation_failure);
566 }
567
568 MonitorLockerEx ml(&_alloc_failure_waiters_lock);
569 while (is_alloc_failure_gc()) {
570 ml.wait();
571 }
572 }
573
574 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) {
575 Thread* t = Thread::current();
576
577 ShenandoahHeap* heap = ShenandoahHeap::heap();
578
579 if (try_set_alloc_failure_gc()) {
580 // Only report the first allocation failure
581 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation",
582 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
583 }
584
585 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac);
586 }
587
588 void ShenandoahControlThread::notify_alloc_failure_waiters() {
589 _alloc_failure_gc.unset();
590 MonitorLockerEx ml(&_alloc_failure_waiters_lock);
591 ml.notify_all();
592 }
593
594 bool ShenandoahControlThread::try_set_alloc_failure_gc() {
595 return _alloc_failure_gc.try_set();
596 }
597
598 bool ShenandoahControlThread::is_alloc_failure_gc() {
599 return _alloc_failure_gc.is_set();
600 }
601
602 void ShenandoahControlThread::notify_gc_waiters() {
603 _gc_requested.unset();
604 MonitorLockerEx ml(&_gc_waiters_lock);
605 ml.notify_all();
606 }
607
608 void ShenandoahControlThread::handle_counters_update() {
609 if (_do_counters_update.is_set()) {
610 _do_counters_update.unset();
611 ShenandoahHeap::heap()->monitoring_support()->update_counters();
612 }
613 }
614
615 void ShenandoahControlThread::handle_force_counters_update() {
616 if (_force_counters_update.is_set()) {
617 _do_counters_update.unset(); // reset these too, we do update now!
618 ShenandoahHeap::heap()->monitoring_support()->update_counters();
619 }
620 }
621
622 void ShenandoahControlThread::notify_heap_changed() {
623 // This is called from allocation path, and thus should be fast.
624
625 // Update monitoring counters when we took a new region. This amortizes the
626 // update costs on slow path.
627 if (_do_counters_update.is_unset()) {
628 _do_counters_update.set();
629 }
630 // Notify that something had changed.
631 if (_heap_changed.is_unset()) {
632 _heap_changed.set();
633 }
634 }
635
636 void ShenandoahControlThread::pacing_notify_alloc(size_t words) {
637 assert(ShenandoahPacing, "should only call when pacing is enabled");
638 Atomic::add(words, &_allocs_seen);
639 }
640
641 void ShenandoahControlThread::set_forced_counters_update(bool value) {
642 _force_counters_update.set_cond(value);
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::makeSurrogateLockerThread(TRAPS) {
660 assert(UseShenandoahGC, "SLT thread needed only for concurrent GC");
661 assert(THREAD->is_Java_thread(), "must be a Java thread");
662 assert(_slt == NULL, "SLT already created");
663 _slt = SurrogateLockerThread::make(THREAD);
664 }
665
666 void ShenandoahControlThread::prepare_for_graceful_shutdown() {
667 _graceful_shutdown.set();
668 }
669
670 bool ShenandoahControlThread::in_graceful_shutdown() {
671 return _graceful_shutdown.is_set();
672 }