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 // Signal that we have completed a visit to all live objects. 240 Universe::heap()->record_whole_heap_examined_timestamp(); 241 } 242 243 // Disable forced counters update, and update counters one more time 244 // to capture the state at the end of GC session. 245 handle_force_counters_update(); 246 set_forced_counters_update(false); 247 248 // Retract forceful part of soft refs policy 249 heap->soft_ref_policy()->set_should_clear_all_soft_refs(false); 250 251 // Clear metaspace oom flag, if current cycle unloaded classes 252 if (heap->unload_classes()) { 253 heuristics->clear_metaspace_oom(); 254 } 255 256 // Commit worker statistics to cycle data 257 heap->phase_timings()->flush_par_workers_to_cycle(); 258 if (ShenandoahPacing) { 259 heap->pacer()->flush_stats_to_cycle(); 260 } 261 262 // Print GC stats for current cycle 263 { 264 LogTarget(Info, gc, stats) lt; 265 if (lt.is_enabled()) { 266 ResourceMark rm; 267 LogStream ls(lt); 268 heap->phase_timings()->print_cycle_on(&ls); 269 if (ShenandoahPacing) { 270 heap->pacer()->print_cycle_on(&ls); 271 } 272 } 273 } 274 275 // Commit statistics to globals 276 heap->phase_timings()->flush_cycle_to_global(); 277 278 // Print Metaspace change following GC (if logging is enabled). 279 MetaspaceUtils::print_metaspace_change(meta_sizes); 280 281 // GC is over, we are at idle now 282 if (ShenandoahPacing) { 283 heap->pacer()->setup_for_idle(); 284 } 285 } else { 286 // Allow allocators to know we have seen this much regions 287 if (ShenandoahPacing && (allocs_seen > 0)) { 288 heap->pacer()->report_alloc(allocs_seen); 289 } 290 } 291 292 double current = os::elapsedTime(); 293 294 if (ShenandoahUncommit && (explicit_gc_requested || (current - last_shrink_time > shrink_period))) { 295 // Try to uncommit enough stale regions. Explicit GC tries to uncommit everything. 296 // Regular paths uncommit only occasionally. 297 double shrink_before = explicit_gc_requested ? 298 current : 299 current - (ShenandoahUncommitDelay / 1000.0); 300 service_uncommit(shrink_before); 301 heap->phase_timings()->flush_cycle_to_global(); 302 last_shrink_time = current; 303 } 304 305 // Wait before performing the next action. If allocation happened during this wait, 306 // we exit sooner, to let heuristics re-evaluate new conditions. If we are at idle, 307 // back off exponentially. 308 if (_heap_changed.try_unset()) { 309 sleep = ShenandoahControlIntervalMin; 310 } else if ((current - last_sleep_adjust_time) * 1000 > ShenandoahControlIntervalAdjustPeriod){ 311 sleep = MIN2<int>(ShenandoahControlIntervalMax, MAX2(1, sleep * 2)); 312 last_sleep_adjust_time = current; 313 } 314 os::naked_short_sleep(sleep); 315 } 316 317 // Wait for the actual stop(), can't leave run_service() earlier. 318 while (!should_terminate()) { 319 os::naked_short_sleep(ShenandoahControlIntervalMin); 320 } 321 } 322 323 void ShenandoahControlThread::service_concurrent_normal_cycle(GCCause::Cause cause) { 324 // Normal cycle goes via all concurrent phases. If allocation failure (af) happens during 325 // any of the concurrent phases, it first degrades to Degenerated GC and completes GC there. 326 // If second allocation failure happens during Degenerated GC cycle (for example, when GC 327 // tries to evac something and no memory is available), cycle degrades to Full GC. 328 // 329 // There are also a shortcut through the normal cycle: immediate garbage shortcut, when 330 // heuristics says there are no regions to compact, and all the collection comes from immediately 331 // reclaimable regions. 332 // 333 // ................................................................................................ 334 // 335 // (immediate garbage shortcut) Concurrent GC 336 // /-------------------------------------------\ 337 // | | 338 // | | 339 // | | 340 // | v 341 // [START] ----> Conc Mark ----o----> Conc Evac --o--> Conc Update-Refs ---o----> [END] 342 // | | | ^ 343 // | (af) | (af) | (af) | 344 // ..................|....................|.................|..............|....................... 345 // | | | | 346 // | | | | Degenerated GC 347 // v v v | 348 // STW Mark ----------> STW Evac ----> STW Update-Refs ----->o 349 // | | | ^ 350 // | (af) | (af) | (af) | 351 // ..................|....................|.................|..............|....................... 352 // | | | | 353 // | v | | Full GC 354 // \------------------->o<----------------/ | 355 // | | 356 // v | 357 // Full GC --------------------------/ 358 // 359 ShenandoahHeap* heap = ShenandoahHeap::heap(); 360 361 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_outside_cycle)) return; 362 363 GCIdMark gc_id_mark; 364 ShenandoahGCSession session(cause); 365 366 TraceCollectorStats tcs(heap->monitoring_support()->concurrent_collection_counters()); 367 368 // Reset for upcoming marking 369 heap->entry_reset(); 370 371 // Start initial mark under STW 372 heap->vmop_entry_init_mark(); 373 374 // Continue concurrent mark 375 heap->entry_mark(); 376 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_mark)) return; 377 378 // If not cancelled, can try to concurrently pre-clean 379 heap->entry_preclean(); 380 381 // Complete marking under STW, and start evacuation 382 heap->vmop_entry_final_mark(); 383 384 // Process weak roots that might still point to regions that would be broken by cleanup 385 if (heap->is_concurrent_weak_root_in_progress()) { 386 heap->entry_weak_roots(); 387 } 388 389 // Final mark might have reclaimed some immediate garbage, kick cleanup to reclaim 390 // the space. This would be the last action if there is nothing to evacuate. 391 heap->entry_cleanup_early(); 392 393 { 394 ShenandoahHeapLocker locker(heap->lock()); 395 heap->free_set()->log_status(); 396 } 397 398 // Perform concurrent class unloading 399 if (heap->is_concurrent_weak_root_in_progress()) { 400 heap->entry_class_unloading(); 401 } 402 403 // Processing strong roots 404 // This may be skipped if there is nothing to update/evacuate. 405 // If so, strong_root_in_progress would be unset. 406 if (heap->is_concurrent_strong_root_in_progress()) { 407 heap->entry_strong_roots(); 408 } 409 410 // Continue the cycle with evacuation and optional update-refs. 411 // This may be skipped if there is nothing to evacuate. 412 // If so, evac_in_progress would be unset by collection set preparation code. 413 if (heap->is_evacuation_in_progress()) { 414 // Concurrently evacuate 415 heap->entry_evac(); 416 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_evac)) return; 417 418 // Perform update-refs phase. 419 heap->vmop_entry_init_updaterefs(); 420 heap->entry_updaterefs(); 421 if (check_cancellation_or_degen(ShenandoahHeap::_degenerated_updaterefs)) return; 422 423 heap->vmop_entry_final_updaterefs(); 424 425 // Update references freed up collection set, kick the cleanup to reclaim the space. 426 heap->entry_cleanup_complete(); 427 } 428 429 // Cycle is complete 430 heap->heuristics()->record_success_concurrent(); 431 heap->shenandoah_policy()->record_success_concurrent(); 432 } 433 434 bool ShenandoahControlThread::check_cancellation_or_degen(ShenandoahHeap::ShenandoahDegenPoint point) { 435 ShenandoahHeap* heap = ShenandoahHeap::heap(); 436 if (heap->cancelled_gc()) { 437 assert (is_alloc_failure_gc() || in_graceful_shutdown(), "Cancel GC either for alloc failure GC, or gracefully exiting"); 438 if (!in_graceful_shutdown()) { 439 assert (_degen_point == ShenandoahHeap::_degenerated_outside_cycle, 440 "Should not be set yet: %s", ShenandoahHeap::degen_point_to_string(_degen_point)); 441 _degen_point = point; 442 } 443 return true; 444 } 445 return false; 446 } 447 448 void ShenandoahControlThread::stop_service() { 449 // Nothing to do here. 450 } 451 452 void ShenandoahControlThread::service_stw_full_cycle(GCCause::Cause cause) { 453 GCIdMark gc_id_mark; 454 ShenandoahGCSession session(cause); 455 456 ShenandoahHeap* heap = ShenandoahHeap::heap(); 457 heap->vmop_entry_full(cause); 458 459 heap->heuristics()->record_success_full(); 460 heap->shenandoah_policy()->record_success_full(); 461 } 462 463 void ShenandoahControlThread::service_stw_degenerated_cycle(GCCause::Cause cause, ShenandoahHeap::ShenandoahDegenPoint point) { 464 assert (point != ShenandoahHeap::_degenerated_unset, "Degenerated point should be set"); 465 466 GCIdMark gc_id_mark; 467 ShenandoahGCSession session(cause); 468 469 ShenandoahHeap* heap = ShenandoahHeap::heap(); 470 heap->vmop_degenerated(point); 471 472 heap->heuristics()->record_success_degenerated(); 473 heap->shenandoah_policy()->record_success_degenerated(); 474 } 475 476 void ShenandoahControlThread::service_uncommit(double shrink_before) { 477 ShenandoahHeap* heap = ShenandoahHeap::heap(); 478 479 // Determine if there is work to do. This avoids taking heap lock if there is 480 // no work available, avoids spamming logs with superfluous logging messages, 481 // and minimises the amount of work while locks are taken. 482 483 if (heap->committed() <= heap->min_capacity()) return; 484 485 bool has_work = false; 486 for (size_t i = 0; i < heap->num_regions(); i++) { 487 ShenandoahHeapRegion *r = heap->get_region(i); 488 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 489 has_work = true; 490 break; 491 } 492 } 493 494 if (has_work) { 495 heap->entry_uncommit(shrink_before); 496 } 497 } 498 499 bool ShenandoahControlThread::is_explicit_gc(GCCause::Cause cause) const { 500 return GCCause::is_user_requested_gc(cause) || 501 GCCause::is_serviceability_requested_gc(cause); 502 } 503 504 void ShenandoahControlThread::request_gc(GCCause::Cause cause) { 505 assert(GCCause::is_user_requested_gc(cause) || 506 GCCause::is_serviceability_requested_gc(cause) || 507 cause == GCCause::_metadata_GC_clear_soft_refs || 508 cause == GCCause::_full_gc_alot || 509 cause == GCCause::_wb_full_gc || 510 cause == GCCause::_scavenge_alot, 511 "only requested GCs here"); 512 513 if (is_explicit_gc(cause)) { 514 if (!DisableExplicitGC) { 515 handle_requested_gc(cause); 516 } 517 } else { 518 handle_requested_gc(cause); 519 } 520 } 521 522 void ShenandoahControlThread::handle_requested_gc(GCCause::Cause cause) { 523 // Make sure we have at least one complete GC cycle before unblocking 524 // from the explicit GC request. 525 // 526 // This is especially important for weak references cleanup and/or native 527 // resources (e.g. DirectByteBuffers) machinery: when explicit GC request 528 // comes very late in the already running cycle, it would miss lots of new 529 // opportunities for cleanup that were made available before the caller 530 // requested the GC. 531 532 MonitorLocker ml(&_gc_waiters_lock); 533 size_t current_gc_id = get_gc_id(); 534 size_t required_gc_id = current_gc_id + 1; 535 while (current_gc_id < required_gc_id) { 536 _gc_requested.set(); 537 _requested_gc_cause = cause; 538 ml.wait(); 539 current_gc_id = get_gc_id(); 540 } 541 } 542 543 void ShenandoahControlThread::handle_alloc_failure(ShenandoahAllocRequest& req) { 544 ShenandoahHeap* heap = ShenandoahHeap::heap(); 545 546 assert(current()->is_Java_thread(), "expect Java thread here"); 547 548 if (try_set_alloc_failure_gc()) { 549 // Only report the first allocation failure 550 log_info(gc)("Failed to allocate %s, " SIZE_FORMAT "%s", 551 req.type_string(), 552 byte_size_in_proper_unit(req.size() * HeapWordSize), proper_unit_for_byte_size(req.size() * HeapWordSize)); 553 554 // Now that alloc failure GC is scheduled, we can abort everything else 555 heap->cancel_gc(GCCause::_allocation_failure); 556 } 557 558 MonitorLocker ml(&_alloc_failure_waiters_lock); 559 while (is_alloc_failure_gc()) { 560 ml.wait(); 561 } 562 } 563 564 void ShenandoahControlThread::handle_alloc_failure_evac(size_t words) { 565 ShenandoahHeap* heap = ShenandoahHeap::heap(); 566 567 if (try_set_alloc_failure_gc()) { 568 // Only report the first allocation failure 569 log_info(gc)("Failed to allocate " SIZE_FORMAT "%s for evacuation", 570 byte_size_in_proper_unit(words * HeapWordSize), proper_unit_for_byte_size(words * HeapWordSize)); 571 } 572 573 // Forcefully report allocation failure 574 heap->cancel_gc(GCCause::_shenandoah_allocation_failure_evac); 575 } 576 577 void ShenandoahControlThread::notify_alloc_failure_waiters() { 578 _alloc_failure_gc.unset(); 579 MonitorLocker ml(&_alloc_failure_waiters_lock); 580 ml.notify_all(); 581 } 582 583 bool ShenandoahControlThread::try_set_alloc_failure_gc() { 584 return _alloc_failure_gc.try_set(); 585 } 586 587 bool ShenandoahControlThread::is_alloc_failure_gc() { 588 return _alloc_failure_gc.is_set(); 589 } 590 591 void ShenandoahControlThread::notify_gc_waiters() { 592 _gc_requested.unset(); 593 MonitorLocker ml(&_gc_waiters_lock); 594 ml.notify_all(); 595 } 596 597 void ShenandoahControlThread::handle_counters_update() { 598 if (_do_counters_update.is_set()) { 599 _do_counters_update.unset(); 600 ShenandoahHeap::heap()->monitoring_support()->update_counters(); 601 } 602 } 603 604 void ShenandoahControlThread::handle_force_counters_update() { 605 if (_force_counters_update.is_set()) { 606 _do_counters_update.unset(); // reset these too, we do update now! 607 ShenandoahHeap::heap()->monitoring_support()->update_counters(); 608 } 609 } 610 611 void ShenandoahControlThread::notify_heap_changed() { 612 // This is called from allocation path, and thus should be fast. 613 614 // Update monitoring counters when we took a new region. This amortizes the 615 // update costs on slow path. 616 if (_do_counters_update.is_unset()) { 617 _do_counters_update.set(); 618 } 619 // Notify that something had changed. 620 if (_heap_changed.is_unset()) { 621 _heap_changed.set(); 622 } 623 } 624 625 void ShenandoahControlThread::pacing_notify_alloc(size_t words) { 626 assert(ShenandoahPacing, "should only call when pacing is enabled"); 627 Atomic::add(&_allocs_seen, words); 628 } 629 630 void ShenandoahControlThread::set_forced_counters_update(bool value) { 631 _force_counters_update.set_cond(value); 632 } 633 634 void ShenandoahControlThread::reset_gc_id() { 635 Atomic::store(&_gc_id, (size_t)0); 636 } 637 638 void ShenandoahControlThread::update_gc_id() { 639 Atomic::inc(&_gc_id); 640 } 641 642 size_t ShenandoahControlThread::get_gc_id() { 643 return Atomic::load(&_gc_id); 644 } 645 646 void ShenandoahControlThread::print() const { 647 print_on(tty); 648 } 649 650 void ShenandoahControlThread::print_on(outputStream* st) const { 651 st->print("Shenandoah Concurrent Thread"); 652 Thread::print_on(st); 653 st->cr(); 654 } 655 656 void ShenandoahControlThread::start() { 657 create_and_start(); 658 } 659 660 void ShenandoahControlThread::prepare_for_graceful_shutdown() { 661 _graceful_shutdown.set(); 662 } 663 664 bool ShenandoahControlThread::in_graceful_shutdown() { 665 return _graceful_shutdown.is_set(); 666 }