1 /*
2 * Copyright (c) 2013, 2020, 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/shenandoahMonitoringSupport.hpp"
34 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
35 #include "gc_implementation/shenandoah/shenandoahUtils.hpp"
36 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp"
37 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp"
38 #include "gc_implementation/shenandoah/heuristics/shenandoahHeuristics.hpp"
39 #include "memory/iterator.hpp"
40 #include "memory/universe.hpp"
41
42 #ifdef _WINDOWS
43 #pragma warning(disable : 4355)
44 #endif
45
46 SurrogateLockerThread* ShenandoahControlThread::_slt = NULL;
47
48 ShenandoahControlThread::ShenandoahControlThread() :
49 ConcurrentGCThread(),
50 _alloc_failure_waiters_lock(Mutex::leaf, "ShenandoahAllocFailureGC_lock", true),
51 _gc_waiters_lock(Mutex::leaf, "ShenandoahRequestedGC_lock", true),
52 _periodic_task(this),
53 _requested_gc_cause(GCCause::_no_cause_specified),
54 _degen_point(ShenandoahHeap::_degenerated_outside_cycle),
55 _allocs_seen(0) {
56
57 reset_gc_id();
58 if (os::create_thread(this, os::cgc_thread)) {
59 os::set_native_priority(this, os::java_to_os_priority[NearMaxPriority]);
60 if (!_should_terminate && !DisableStartThread) {
61 os::start_thread(this);
62 }
63 }
64
65 _periodic_task.enroll();
66 _periodic_satb_flush_task.enroll();
67 if (ShenandoahPacing) {
68 _periodic_pacer_notify_task.enroll();
69 }
70 }
71
72 ShenandoahControlThread::~ShenandoahControlThread() {
73 // This is here so that super is called.
74 }
75
76 void ShenandoahPeriodicTask::task() {
77 _thread->handle_force_counters_update();
78 _thread->handle_counters_update();
79 }
80
81 void ShenandoahPeriodicSATBFlushTask::task() {
82 ShenandoahHeap::heap()->force_satb_flush_all_threads();
83 }
84
85 void ShenandoahPeriodicPacerNotify::task() {
86 assert(ShenandoahPacing, "Should not be here otherwise");
87 ShenandoahHeap::heap()->pacer()->notify_waiters();
88 }
89
90 void ShenandoahControlThread::run() {
91 initialize_in_thread();
92
93 wait_for_universe_init();
94
95 // Wait until we have the surrogate locker thread in place.
96 {
97 MutexLockerEx x(CGC_lock, true);
98 while(_slt == NULL && !_should_terminate) {
99 CGC_lock->wait(true, 200);
100 }
101 }
102
103 ShenandoahHeap* heap = ShenandoahHeap::heap();
104
105 GCMode default_mode = concurrent_normal;
106 GCCause::Cause default_cause = 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 // Check if we have seen a new target for soft max heap size.
131 bool soft_max_changed = check_soft_max_changed();
132
133 // Choose which GC mode to run in. The block below should select a single mode.
134 GCMode mode = none;
135 GCCause::Cause cause = GCCause::_last_gc_cause;
136 ShenandoahHeap::ShenandoahDegenPoint degen_point = ShenandoahHeap::_degenerated_unset;
137
138 if (alloc_failure_pending) {
139 // Allocation failure takes precedence: we have to deal with it first thing
140 log_info(gc)("Trigger: Handle Allocation Failure");
141
142 cause = GCCause::_allocation_failure;
143
144 // Consume the degen point, and seed it with default value
145 degen_point = _degen_point;
146 _degen_point = ShenandoahHeap::_degenerated_outside_cycle;
147
148 if (ShenandoahDegeneratedGC && heuristics->should_degenerate_cycle()) {
149 heuristics->record_allocation_failure_gc();
150 policy->record_alloc_failure_to_degenerated(degen_point);
151 mode = stw_degenerated;
152 } else {
153 heuristics->record_allocation_failure_gc();
154 policy->record_alloc_failure_to_full();
155 mode = stw_full;
156 }
157
158 } else if (explicit_gc_requested) {
159 cause = _requested_gc_cause;
160 log_info(gc)("Trigger: Explicit GC request (%s)", GCCause::to_string(cause));
161
162 heuristics->record_requested_gc();
163
164 if (ExplicitGCInvokesConcurrent) {
165 policy->record_explicit_to_concurrent();
166 mode = default_mode;
167 // Unload and clean up everything
168 heap->set_process_references(heuristics->can_process_references());
169 heap->set_unload_classes(heuristics->can_unload_classes());
170 } else {
171 policy->record_explicit_to_full();
172 mode = stw_full;
173 }
174 } else if (implicit_gc_requested) {
175 cause = _requested_gc_cause;
176 log_info(gc)("Trigger: Implicit GC request (%s)", GCCause::to_string(cause));
177
178 heuristics->record_requested_gc();
179
180 if (ShenandoahImplicitGCInvokesConcurrent) {
181 policy->record_implicit_to_concurrent();
182 mode = default_mode;
183
184 // Unload and clean up everything
185 heap->set_process_references(heuristics->can_process_references());
186 heap->set_unload_classes(heuristics->can_unload_classes());
187 } else {
188 policy->record_implicit_to_full();
189 mode = stw_full;
190 }
191 } else {
192 // Potential normal cycle: ask heuristics if it wants to act
193 if (heuristics->should_start_gc()) {
194 mode = default_mode;
195 cause = default_cause;
196 }
197
198 // Ask policy if this cycle wants to process references or unload classes
199 heap->set_process_references(heuristics->should_process_references());
200 heap->set_unload_classes(heuristics->should_unload_classes());
201 }
202
203 // Blow all soft references on this cycle, if handling allocation failure,
204 // either implicit or explicit GC request, or we are requested to do so unconditionally.
205 if (alloc_failure_pending || implicit_gc_requested || explicit_gc_requested || ShenandoahAlwaysClearSoftRefs) {
206 heap->collector_policy()->set_should_clear_all_soft_refs(true);
207 }
208
209 bool gc_requested = (mode != none);
210 assert (!gc_requested || cause != GCCause::_last_gc_cause, "GC cause should be set");
211
212 if (gc_requested) {
213 // GC is starting, bump the internal ID
214 update_gc_id();
215
216 heap->reset_bytes_allocated_since_gc_start();
217
218 // Capture metaspace usage before GC.
219 const size_t metadata_prev_used = MetaspaceAux::used_bytes();
220
221 // If GC was requested, we are sampling the counters even without actual triggers
222 // from allocation machinery. This captures GC phases more accurately.
223 set_forced_counters_update(true);
224
225 // If GC was requested, we better dump freeset data for performance debugging
226 {
227 ShenandoahHeapLocker locker(heap->lock());
228 heap->free_set()->log_status();
229 }
230
231 switch (mode) {
232 case none:
233 break;
234 case concurrent_normal:
235 service_concurrent_normal_cycle(cause);
236 break;
237 case stw_degenerated:
238 service_stw_degenerated_cycle(cause, degen_point);
239 break;
240 case stw_full:
241 service_stw_full_cycle(cause);
242 break;
243 default:
244 ShouldNotReachHere();
245 }
246
247 // If this was the requested GC cycle, notify waiters about it
248 if (explicit_gc_requested || implicit_gc_requested) {
249 notify_gc_waiters();
250 }
251
252 // If this was the allocation failure GC cycle, notify waiters about it
253 if (alloc_failure_pending) {
254 notify_alloc_failure_waiters();
255 }
256
257 // Report current free set state at the end of cycle, whether
258 // it is a normal completion, or the abort.
259 {
260 ShenandoahHeapLocker locker(heap->lock());
261 heap->free_set()->log_status();
262
263 // Notify Universe about new heap usage. This has implications for
264 // global soft refs policy, and we better report it every time heap
265 // usage goes down.
266 Universe::update_heap_info_at_gc();
267 }
268
269 // Disable forced counters update, and update counters one more time
270 // to capture the state at the end of GC session.
271 handle_force_counters_update();
272 set_forced_counters_update(false);
273
274 // Retract forceful part of soft refs policy
275 heap->collector_policy()->set_should_clear_all_soft_refs(false);
276
277 // Clear metaspace oom flag, if current cycle unloaded classes
278 if (heap->unload_classes()) {
279 heuristics->clear_metaspace_oom();
280 }
281
282 // Commit worker statistics to cycle data
283 heap->phase_timings()->flush_par_workers_to_cycle();
284 if (ShenandoahPacing) {
285 heap->pacer()->flush_stats_to_cycle();
286 }
287
288 // Print GC stats for current cycle
289 if (PrintGCDetails) {
290 ResourceMark rm;
291 heap->phase_timings()->print_cycle_on(gclog_or_tty);
292 if (ShenandoahPacing) {
293 heap->pacer()->print_cycle_on(gclog_or_tty);
294 }
295 }
296
297 // Commit statistics to globals
298 heap->phase_timings()->flush_cycle_to_global();
299
300 // Print Metaspace change following GC (if logging is enabled).
301 if (PrintGCDetails) {
302 MetaspaceAux::print_metaspace_change(metadata_prev_used);
303 }
304
305 // GC is over, we are at idle now
306 if (ShenandoahPacing) {
307 heap->pacer()->setup_for_idle();
308 }
309 } else {
310 // Allow allocators to know we have seen this much regions
311 if (ShenandoahPacing && (allocs_seen > 0)) {
312 heap->pacer()->report_alloc(allocs_seen);
313 }
314 }
315
316 double current = os::elapsedTime();
317
318 if (ShenandoahUncommit && (explicit_gc_requested || soft_max_changed || (current - last_shrink_time > shrink_period))) {
319 // Explicit GC tries to uncommit everything down to min capacity.
320 // Soft max change tries to uncommit everything down to target capacity.
321 // Periodic uncommit tries to uncommit suitable regions down to min capacity.
322
323 double shrink_before = (explicit_gc_requested || soft_max_changed) ?
324 current :
325 current - (ShenandoahUncommitDelay / 1000.0);
326
327 size_t shrink_until = soft_max_changed ?
328 heap->soft_max_capacity() :
329 heap->min_capacity();
330
331 service_uncommit(shrink_before, shrink_until);
332 heap->phase_timings()->flush_cycle_to_global();
333 last_shrink_time = current;
334 }
335
336 // Wait before performing the next action. If allocation happened during this wait,
337 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle,
338 // back off exponentially.
339 if (_heap_changed.try_unset()) {
340 sleep = ShenandoahControlIntervalMin;
341 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){
342 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2));
343 last_sleep_adjust_time = current;
344 }
345 os::naked_short_sleep(sleep);
346 }
347
348 // Wait for the actual stop(), can't leave run_service() earlier.
349 while (! _should_terminate) {
350 os::naked_short_sleep(ShenandoahControlIntervalMin);
351 }
352 terminate();
353 }
354
355 bool ShenandoahControlThread::check_soft_max_changed() const {
356 ShenandoahHeap* heap = ShenandoahHeap::heap();
357 size_t new_soft_max = OrderAccess::load_acquire(&ShenandoahSoftMaxHeapSize);
358 size_t old_soft_max = heap->soft_max_capacity();
359 if (new_soft_max != old_soft_max) {
360 new_soft_max = MAX2(heap->min_capacity(), new_soft_max);
361 new_soft_max = MIN2(heap->max_capacity(), new_soft_max);
362 if (new_soft_max != old_soft_max) {
363 log_info(gc)("Soft Max Heap Size: " SIZE_FORMAT "%s -> " SIZE_FORMAT "%s",
364 byte_size_in_proper_unit(old_soft_max), proper_unit_for_byte_size(old_soft_max),
365 byte_size_in_proper_unit(new_soft_max), proper_unit_for_byte_size(new_soft_max)
366 );
367 heap->set_soft_max_capacity(new_soft_max);
368 return true;
369 }
370 }
371 return false;
372 }
373
374 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) {
375 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during
376 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there.
377 // If second allocation failure happens during Degenerated GC cycle (for example, when GC
378 // tries to evac something and no memory is available), cycle degrades to Full GC.
379 //
380 // There are also a shortcut through the normal cycle: immediate garbage shortcut, when
381 // heuristics says there are no regions to compact, and all the collection comes from immediately
382 // reclaimable regions.
383 //
384 // ................................................................................................
385 //
386 // (immediate garbage shortcut) Concurrent GC
387 // /-------------------------------------------\
388 // | |
389 // | |
390 // | |
391 // | v
392 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END]
393 // | | | ^
394 // | (af) | (af) | (af) |
395 // ..................|....................|.................|..............|.......................
396 // | | | |
397 // | | | | Degenerated GC
398 // v v v |
399 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o
400 // | | | ^
401 // | (af) | (af) | (af) |
402 // ..................|....................|.................|..............|.......................
403 // | | | |
404 // | v | | Full GC
405 // \------------------->o<----------------/ |
406 // | |
407 // v |
408 // Full GC --------------------------/
409 //
410
411 ShenandoahHeap* heap = ShenandoahHeap::heap();
412
413 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_outside_cycle)) return;
414
415 ShenandoahGCSession session(cause);
416
417 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters());
418
419 // Reset for upcoming marking
420 heap->entry_reset();
421
422 // Start initial mark under STW
423 heap->vmop_entry_init_mark();
424
425 // Continue concurrent mark
426 heap->entry_mark();
427 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_mark)) return;
428
429 // If not cancelled, can try to concurrently pre-clean
430 heap->entry_preclean();
431
432 // Complete marking under STW, and start evacuation
433 heap->vmop_entry_final_mark();
434
435 // Final mark might have reclaimed some immediate garbage, kick cleanup to reclaim
436 // the space. This would be the last action if there is nothing to evacuate.
437 heap->entry_cleanup_early();
438
439 {
440 ShenandoahHeapLocker locker(heap->lock());
441 heap->free_set()->log_status();
442 }
443
444 // Continue the cycle with evacuation and optional update-refs.
445 // This may be skipped if there is nothing to evacuate.
446 // If so, evac_in_progress would be unset by collection set preparation code.
447 if (heap->is_evacuation_in_progress()) {
448 // Concurrently evacuate
449 heap->entry_evac();
450 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_evac)) return;
451
452 // Perform update-refs phase.
453 heap->vmop_entry_init_updaterefs();
454 heap->entry_updaterefs();
455 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_updaterefs)) return;
456
457 heap->vmop_entry_final_updaterefs();
458
459 // Update references freed up collection set, kick the cleanup to reclaim the space.
460 heap->entry_cleanup_complete();
461 }
462
463 // Cycle is complete
464 heap->heuristics()->record_success_concurrent();
465 heap->shenandoah_policy()->record_success_concurrent();
466 }
467
468 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point) {
469 ShenandoahHeap* heap = ShenandoahHeap::heap();
470 if (heap->cancelled_gc()) {
471 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting");
472 if (!in_graceful_shutdown()) {
473 assert (_degen_point == ShenandoahHeap::_degenerated_outside_cycle,
474 err_msg("Should not be set yet: %s", ShenandoahHeap::degen_point_to_string(_degen_point)));
475 _degen_point = point;
476 }
477 return true;
478 }
479 return false;
480 }
481
482 void ShenandoahControlThread::stop() {
483 {
484 MutexLockerEx ml(Terminator_lock);
485 _should_terminate = true;
486 }
487
488 {
489 MutexLockerEx ml(CGC_lock, Mutex::_no_safepoint_check_flag);
490 CGC_lock->notify_all();
491 }
492
493 {
494 MutexLockerEx ml(Terminator_lock);
495 while (!_has_terminated) {
496 Terminator_lock->wait();
497 }
498 }
499 }
500
501 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) {
502 ShenandoahHeap* heap = ShenandoahHeap::heap();
503 ShenandoahGCSession session(cause);
504
505 heap->vmop_entry_full(cause);
506
507 heap->heuristics()->record_success_full();
508 heap->shenandoah_policy()->record_success_full();
509 }
510
511 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point) {
512 assert (point != ShenandoahHeap::_degenerated_unset, "Degenerated point should be set");
513 ShenandoahHeap* heap = ShenandoahHeap::heap();
514 ShenandoahGCSession session(cause);
515
516 heap->vmop_degenerated(point);
517
518 heap->heuristics()->record_success_degenerated();
519 heap->shenandoah_policy()->record_success_degenerated();
520 }
521
522 void ShenandoahControlThread::service_uncommit(double shrink_before, size_t shrink_until) {
523 ShenandoahHeap* heap = ShenandoahHeap::heap();
524
525 // Determine if there is work to do. This avoids taking heap lock if there is
526 // no work available, avoids spamming logs with superfluous logging messages,
527 // and minimises the amount of work while locks are taken.
528
529 if (heap->committed() <= shrink_until) return;
530
531 bool has_work = false;
532 for (size_t i = 0; i < heap->num_regions(); i++) {
533 ShenandoahHeapRegion *r = heap->get_region(i);
534 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
535 has_work = true;
536 break;
537 }
538 }
539
540 if (has_work) {
541 heap->entry_uncommit(shrink_before, shrink_until);
542 }
543 }
544
545 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const {
546 return GCCause::is_user_requested_gc(cause) ||
547 GCCause::is_serviceability_requested_gc(cause);
548 }
549
550 void ShenandoahControlThread::request_gc(GCCause::Cause cause) {
551 assert(GCCause::is_user_requested_gc(cause) ||
552 GCCause::is_serviceability_requested_gc(cause) ||
553 cause == GCCause::_shenandoah_metadata_gc_clear_softrefs ||
554 cause == GCCause::_full_gc_alot ||
555 cause == GCCause::_scavenge_alot,
556 "only requested GCs here");
557
558 if (is_explicit_gc(cause)) {
559 if (!DisableExplicitGC) {
560 handle_requested_gc(cause);
561 }
562 } else {
563 handle_requested_gc(cause);
564 }
565 }
566
567 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) {
568 // Make sure we have at least one complete GC cycle before unblocking
569 // from the explicit GC request.
570 //
571 // This is especially important for weak references cleanup and/or native
572 // resources (e.g. DirectByteBuffers) machinery: when explicit GC request
573 // comes very late in the already running cycle, it would miss lots of new
574 // opportunities for cleanup that were made available before the caller
575 // requested the GC.
576
577 MonitorLockerEx ml(&_gc_waiters_lock);
578 size_t current_gc_id = get_gc_id();
579 size_t required_gc_id = current_gc_id + 1;
580 while (current_gc_id < required_gc_id) {
581 _gc_requested.set();
582 _requested_gc_cause = cause;
583 ml.wait();
584 current_gc_id = get_gc_id();
585 }
586 }
587
588 void ShenandoahControlThread::handle_alloc_failure(ShenandoahAllocRequest& req) {
589 ShenandoahHeap* heap = ShenandoahHeap::heap();
590
591 assert(current()->is_Java_thread(), "expect Java thread here");
592
593 if (try_set_alloc_failure_gc()) {
594 // Only report the first allocation failure
595 log_info(gc)("Failed to allocate %s, " SIZE_FORMAT "%s",
596 req.type_string(),
597 byte_size_in_proper_unit(req.size() * HeapWordSize), proper_unit_for_byte_size(req.size() * HeapWordSize));
598
599 // Now that alloc failure GC is scheduled, we can abort everything else
600 heap->cancel_gc(GCCause::_allocation_failure);
601 }
602
603 MonitorLockerEx ml(&_alloc_failure_waiters_lock);
604 while (is_alloc_failure_gc()) {
605 ml.wait();
606 }
607 }
608
609 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) {
610 Thread* t = Thread::current();
611
612 ShenandoahHeap* heap = ShenandoahHeap::heap();
613
614 if (try_set_alloc_failure_gc()) {
615 // Only report the first allocation failure
616 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation",
617 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize));
618 }
619
620 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac);
621 }
622
623 void ShenandoahControlThread::notify_alloc_failure_waiters() {
624 _alloc_failure_gc.unset();
625 MonitorLockerEx ml(&_alloc_failure_waiters_lock);
626 ml.notify_all();
627 }
628
629 bool ShenandoahControlThread::try_set_alloc_failure_gc() {
630 return _alloc_failure_gc.try_set();
631 }
632
633 bool ShenandoahControlThread::is_alloc_failure_gc() {
634 return _alloc_failure_gc.is_set();
635 }
636
637 void ShenandoahControlThread::notify_gc_waiters() {
638 _gc_requested.unset();
639 MonitorLockerEx ml(&_gc_waiters_lock);
640 ml.notify_all();
641 }
642
643 void ShenandoahControlThread::handle_counters_update() {
644 if (_do_counters_update.is_set()) {
645 _do_counters_update.unset();
646 ShenandoahHeap::heap()->monitoring_support()->update_counters();
647 }
648 }
649
650 void ShenandoahControlThread::handle_force_counters_update() {
651 if (_force_counters_update.is_set()) {
652 _do_counters_update.unset(); // reset these too, we do update now!
653 ShenandoahHeap::heap()->monitoring_support()->update_counters();
654 }
655 }
656
657 void ShenandoahControlThread::notify_heap_changed() {
658 // This is called from allocation path, and thus should be fast.
659
660 // Update monitoring counters when we took a new region. This amortizes the
661 // update costs on slow path.
662 if (_do_counters_update.is_unset()) {
663 _do_counters_update.set();
664 }
665 // Notify that something had changed.
666 if (_heap_changed.is_unset()) {
667 _heap_changed.set();
668 }
669 }
670
671 void ShenandoahControlThread::pacing_notify_alloc(size_t words) {
672 assert(ShenandoahPacing, "should only call when pacing is enabled");
673 Atomic::add(words, &_allocs_seen);
674 }
675
676 void ShenandoahControlThread::set_forced_counters_update(bool value) {
677 _force_counters_update.set_cond(value);
678 }
679
680 void ShenandoahControlThread::reset_gc_id() {
681 OrderAccess::release_store_ptr_fence(&_gc_id, 0);
682 }
683
684 void ShenandoahControlThread::update_gc_id() {
685 Atomic::add(1, &_gc_id);
686 }
687
688 size_t ShenandoahControlThread::get_gc_id() {
689 return OrderAccess::load_acquire(&_gc_id);
690 }
691
692 void ShenandoahControlThread::print() const {
693 print_on(tty);
694 }
695
696 void ShenandoahControlThread::print_on(outputStream* st) const {
697 st->print("Shenandoah Concurrent Thread");
698 Thread::print_on(st);
699 st->cr();
700 }
701
702 void ShenandoahControlThread::start() {
703 create_and_start();
704 }
705
706 void ShenandoahControlThread::makeSurrogateLockerThread(TRAPS) {
707 assert(UseShenandoahGC, "SLT thread needed only for concurrent GC");
708 assert(THREAD->is_Java_thread(), "must be a Java thread");
709 assert(_slt == NULL, "SLT already created");
710 _slt = SurrogateLockerThread::make(THREAD);
711 }
712
713 void ShenandoahControlThread::prepare_for_graceful_shutdown() {
714 _graceful_shutdown.set();
715 }
716
717 bool ShenandoahControlThread::in_graceful_shutdown() {
718 return _graceful_shutdown.is_set();
719 }