1 /* 2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2013, 2021, Red Hat, Inc. All rights reserved. 4 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved. 5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 6 * 7 * This code is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 only, as 9 * published by the Free Software Foundation. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 * 25 */ 26 27 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP 28 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP 29 30 #include "gc/shared/ageTable.hpp" 31 #include "gc/shared/markBitMap.hpp" 32 #include "gc/shared/softRefPolicy.hpp" 33 #include "gc/shared/collectedHeap.hpp" 34 #include "gc/shenandoah/shenandoahAgeCensus.hpp" 35 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp" 36 #include "gc/shenandoah/shenandoahAsserts.hpp" 37 #include "gc/shenandoah/shenandoahAllocRequest.hpp" 38 #include "gc/shenandoah/shenandoahAsserts.hpp" 39 #include "gc/shenandoah/shenandoahLock.hpp" 40 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp" 41 #include "gc/shenandoah/shenandoahEvacTracker.hpp" 42 #include "gc/shenandoah/shenandoahGenerationType.hpp" 43 #include "gc/shenandoah/shenandoahMmuTracker.hpp" 44 #include "gc/shenandoah/shenandoahPadding.hpp" 45 #include "gc/shenandoah/shenandoahScanRemembered.hpp" 46 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 47 #include "gc/shenandoah/shenandoahUnload.hpp" 48 #include "memory/metaspace.hpp" 49 #include "services/memoryManager.hpp" 50 #include "utilities/globalDefinitions.hpp" 51 #include "utilities/stack.hpp" 52 53 class ConcurrentGCTimer; 54 class ObjectIterateScanRootClosure; 55 class PLAB; 56 class ShenandoahCollectorPolicy; 57 class ShenandoahControlThread; 58 class ShenandoahRegulatorThread; 59 class ShenandoahGCSession; 60 class ShenandoahGCStateResetter; 61 class ShenandoahGeneration; 62 class ShenandoahYoungGeneration; 63 class ShenandoahOldGeneration; 64 class ShenandoahHeuristics; 65 class ShenandoahOldHeuristics; 66 class ShenandoahYoungHeuristics; 67 class ShenandoahMarkingContext; 68 class ShenandoahPhaseTimings; 69 class ShenandoahHeap; 70 class ShenandoahHeapRegion; 71 class ShenandoahHeapRegionClosure; 72 class ShenandoahCollectionSet; 73 class ShenandoahFreeSet; 74 class ShenandoahConcurrentMark; 75 class ShenandoahFullGC; 76 class ShenandoahMonitoringSupport; 77 class ShenandoahMode; 78 class ShenandoahPacer; 79 class ShenandoahReferenceProcessor; 80 class ShenandoahVerifier; 81 class ShenandoahWorkerThreads; 82 class VMStructs; 83 84 // Used for buffering per-region liveness data. 85 // Needed since ShenandoahHeapRegion uses atomics to update liveness. 86 // The ShenandoahHeap array has max-workers elements, each of which is an array of 87 // uint16_t * max_regions. The choice of uint16_t is not accidental: 88 // there is a tradeoff between static/dynamic footprint that translates 89 // into cache pressure (which is already high during marking), and 90 // too many atomic updates. uint32_t is too large, uint8_t is too small. 91 typedef uint16_t ShenandoahLiveData; 92 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1) 93 94 class ShenandoahRegionIterator : public StackObj { 95 private: 96 ShenandoahHeap* _heap; 97 98 shenandoah_padding(0); 99 volatile size_t _index; 100 shenandoah_padding(1); 101 102 // No implicit copying: iterators should be passed by reference to capture the state 103 NONCOPYABLE(ShenandoahRegionIterator); 104 105 public: 106 ShenandoahRegionIterator(); 107 ShenandoahRegionIterator(ShenandoahHeap* heap); 108 109 // Reset iterator to default state 110 void reset(); 111 112 // Returns next region, or null if there are no more regions. 113 // This is multi-thread-safe. 114 inline ShenandoahHeapRegion* next(); 115 116 // This is *not* MT safe. However, in the absence of multithreaded access, it 117 // can be used to determine if there is more work to do. 118 bool has_next() const; 119 }; 120 121 class ShenandoahHeapRegionClosure : public StackObj { 122 public: 123 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0; 124 virtual bool is_thread_safe() { return false; } 125 }; 126 127 template<ShenandoahGenerationType GENERATION> 128 class ShenandoahGenerationRegionClosure : public ShenandoahHeapRegionClosure { 129 public: 130 explicit ShenandoahGenerationRegionClosure(ShenandoahHeapRegionClosure* cl) : _cl(cl) {} 131 void heap_region_do(ShenandoahHeapRegion* r); 132 virtual bool is_thread_safe() { return _cl->is_thread_safe(); } 133 private: 134 ShenandoahHeapRegionClosure* _cl; 135 }; 136 137 typedef ShenandoahLock ShenandoahHeapLock; 138 typedef ShenandoahLocker ShenandoahHeapLocker; 139 typedef Stack<oop, mtGC> ShenandoahScanObjectStack; 140 141 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers 142 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding. 143 // See ShenandoahControlThread for GC cycle structure. 144 // 145 class ShenandoahHeap : public CollectedHeap { 146 friend class ShenandoahAsserts; 147 friend class VMStructs; 148 friend class ShenandoahGCSession; 149 friend class ShenandoahGCStateResetter; 150 friend class ShenandoahParallelObjectIterator; 151 friend class ShenandoahSafepoint; 152 // Supported GC 153 friend class ShenandoahConcurrentGC; 154 friend class ShenandoahOldGC; 155 friend class ShenandoahDegenGC; 156 friend class ShenandoahFullGC; 157 friend class ShenandoahUnload; 158 159 // ---------- Locks that guard important data structures in Heap 160 // 161 private: 162 ShenandoahHeapLock _lock; 163 ShenandoahGeneration* _gc_generation; 164 165 public: 166 ShenandoahHeapLock* lock() { 167 return &_lock; 168 } 169 170 ShenandoahGeneration* active_generation() const { 171 // last or latest generation might be a better name here. 172 return _gc_generation; 173 } 174 175 void set_gc_generation(ShenandoahGeneration* generation) { 176 _gc_generation = generation; 177 } 178 179 ShenandoahHeuristics* heuristics(); 180 ShenandoahOldHeuristics* old_heuristics(); 181 ShenandoahYoungHeuristics* young_heuristics(); 182 183 bool doing_mixed_evacuations(); 184 bool is_old_bitmap_stable() const; 185 bool is_gc_generation_young() const; 186 187 // ---------- Initialization, termination, identification, printing routines 188 // 189 public: 190 static ShenandoahHeap* heap(); 191 192 const char* name() const override { return "Shenandoah"; } 193 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; } 194 195 ShenandoahHeap(ShenandoahCollectorPolicy* policy); 196 jint initialize() override; 197 void post_initialize() override; 198 void initialize_heuristics_generations(); 199 virtual void print_init_logger() const; 200 void initialize_serviceability() override; 201 202 void print_on(outputStream* st) const override; 203 void print_extended_on(outputStream *st) const override; 204 void print_tracing_info() const override; 205 void print_heap_regions_on(outputStream* st) const; 206 207 void stop() override; 208 209 void prepare_for_verify() override; 210 void verify(VerifyOption vo) override; 211 212 bool verify_generation_usage(bool verify_old, size_t old_regions, size_t old_bytes, size_t old_waste, 213 bool verify_young, size_t young_regions, size_t young_bytes, size_t young_waste); 214 215 // WhiteBox testing support. 216 bool supports_concurrent_gc_breakpoints() const override { 217 return true; 218 } 219 220 // ---------- Heap counters and metrics 221 // 222 private: 223 size_t _initial_size; 224 size_t _minimum_size; 225 size_t _promotion_potential; 226 size_t _pad_for_promote_in_place; // bytes of filler 227 size_t _promotable_humongous_regions; 228 size_t _regular_regions_promoted_in_place; 229 230 volatile size_t _soft_max_size; 231 shenandoah_padding(0); 232 volatile size_t _committed; 233 shenandoah_padding(1); 234 235 void increase_used(const ShenandoahAllocRequest& req); 236 237 public: 238 void increase_used(ShenandoahGeneration* generation, size_t bytes); 239 void decrease_used(ShenandoahGeneration* generation, size_t bytes); 240 void increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 241 void decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 242 243 void increase_committed(size_t bytes); 244 void decrease_committed(size_t bytes); 245 246 void reset_bytes_allocated_since_gc_start(); 247 248 size_t min_capacity() const; 249 size_t max_capacity() const override; 250 size_t soft_max_capacity() const; 251 size_t initial_capacity() const; 252 size_t capacity() const override; 253 size_t used() const override; 254 size_t committed() const; 255 256 void set_soft_max_capacity(size_t v); 257 258 // ---------- Workers handling 259 // 260 private: 261 uint _max_workers; 262 ShenandoahWorkerThreads* _workers; 263 ShenandoahWorkerThreads* _safepoint_workers; 264 265 public: 266 uint max_workers(); 267 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN; 268 269 WorkerThreads* workers() const; 270 WorkerThreads* safepoint_workers() override; 271 272 void gc_threads_do(ThreadClosure* tcl) const override; 273 274 // ---------- Heap regions handling machinery 275 // 276 private: 277 MemRegion _heap_region; 278 bool _heap_region_special; 279 size_t _num_regions; 280 ShenandoahHeapRegion** _regions; 281 uint8_t* _affiliations; // Holds array of enum ShenandoahAffiliation, including FREE status in non-generational mode 282 ShenandoahRegionIterator _update_refs_iterator; 283 284 public: 285 286 inline HeapWord* base() const { return _heap_region.start(); } 287 288 inline size_t num_regions() const { return _num_regions; } 289 inline bool is_heap_region_special() { return _heap_region_special; } 290 291 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const; 292 inline size_t heap_region_index_containing(const void* addr) const; 293 294 inline ShenandoahHeapRegion* get_region(size_t region_idx) const; 295 296 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 297 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 298 299 inline ShenandoahMmuTracker* mmu_tracker() { return &_mmu_tracker; }; 300 301 // ---------- GC state machinery 302 // 303 // GC state describes the important parts of collector state, that may be 304 // used to make barrier selection decisions in the native and generated code. 305 // Multiple bits can be set at once. 306 // 307 // Important invariant: when GC state is zero, the heap is stable, and no barriers 308 // are required. 309 // 310 public: 311 enum GCStateBitPos { 312 // Heap has forwarded objects: needs LRB barriers. 313 HAS_FORWARDED_BITPOS = 0, 314 315 // Heap is under marking: needs SATB barriers. 316 // For generational mode, it means either young or old marking, or both. 317 MARKING_BITPOS = 1, 318 319 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED) 320 EVACUATION_BITPOS = 2, 321 322 // Heap is under updating: needs no additional barriers. 323 UPDATEREFS_BITPOS = 3, 324 325 // Heap is under weak-reference/roots processing: needs weak-LRB barriers. 326 WEAK_ROOTS_BITPOS = 4, 327 328 // Young regions are under marking, need SATB barriers. 329 YOUNG_MARKING_BITPOS = 5, 330 331 // Old regions are under marking, need SATB barriers. 332 OLD_MARKING_BITPOS = 6 333 }; 334 335 enum GCState { 336 STABLE = 0, 337 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS, 338 MARKING = 1 << MARKING_BITPOS, 339 EVACUATION = 1 << EVACUATION_BITPOS, 340 UPDATEREFS = 1 << UPDATEREFS_BITPOS, 341 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS, 342 YOUNG_MARKING = 1 << YOUNG_MARKING_BITPOS, 343 OLD_MARKING = 1 << OLD_MARKING_BITPOS 344 }; 345 346 private: 347 ShenandoahSharedBitmap _gc_state; 348 ShenandoahSharedFlag _degenerated_gc_in_progress; 349 ShenandoahSharedFlag _full_gc_in_progress; 350 ShenandoahSharedFlag _full_gc_move_in_progress; 351 ShenandoahSharedFlag _concurrent_strong_root_in_progress; 352 353 size_t _gc_no_progress_count; 354 355 // TODO: Revisit the following comment. It may not accurately represent the true behavior when evacuations fail due to 356 // difficulty finding memory to hold evacuated objects. 357 // 358 // Note that the typical total expenditure on evacuation is less than the associated evacuation reserve because we generally 359 // reserve ShenandoahEvacWaste (> 1.0) times the anticipated evacuation need. In the case that there is an excessive amount 360 // of waste, it may be that one thread fails to grab a new GCLAB, this does not necessarily doom the associated evacuation 361 // effort. If this happens, the requesting thread blocks until some other thread manages to evacuate the offending object. 362 // Only after "all" threads fail to evacuate an object do we consider the evacuation effort to have failed. 363 364 size_t _promoted_reserve; // Bytes reserved within old-gen to hold the results of promotion 365 volatile size_t _promoted_expended; // Bytes of old-gen memory expended on promotions 366 367 size_t _old_evac_reserve; // Bytes reserved within old-gen to hold evacuated objects from old-gen collection set 368 size_t _young_evac_reserve; // Bytes reserved within young-gen to hold evacuated objects from young-gen collection set 369 370 ShenandoahAgeCensus* _age_census; // Age census used for adapting tenuring threshold in generational mode 371 372 // At the end of final mark, but before we begin evacuating, heuristics calculate how much memory is required to 373 // hold the results of evacuating to young-gen and to old-gen. These quantitites, stored in _promoted_reserve, 374 // _old_evac_reserve, and _young_evac_reserve, are consulted prior to rebuilding the free set (ShenandoahFreeSet) 375 // in preparation for evacuation. When the free set is rebuilt, we make sure to reserve sufficient memory in the 376 // collector and old_collector sets to hold if _has_evacuation_reserve_quantities is true. The other time we 377 // rebuild the freeset is at the end of GC, as we prepare to idle GC until the next trigger. In this case, 378 // _has_evacuation_reserve_quantities is false because we don't yet know how much memory will need to be evacuated 379 // in the next GC cycle. When _has_evacuation_reserve_quantities is false, the free set rebuild operation reserves 380 // for the collector and old_collector sets based on alternative mechanisms, such as ShenandoahEvacReserve, 381 // ShenandoahOldEvacReserve, and ShenandoahOldCompactionReserve. In a future planned enhancement, the reserve 382 // for old_collector set when not _has_evacuation_reserve_quantities is based in part on anticipated promotion as 383 // determined by analysis of live data found during the previous GC pass which is one less than the current tenure age. 384 bool _has_evacuation_reserve_quantities; 385 386 void set_gc_state_all_threads(char state); 387 void set_gc_state_mask(uint mask, bool value); 388 389 public: 390 char gc_state() const; 391 392 void set_evacuation_reserve_quantities(bool is_valid); 393 void set_concurrent_young_mark_in_progress(bool in_progress); 394 void set_concurrent_old_mark_in_progress(bool in_progress); 395 void set_evacuation_in_progress(bool in_progress); 396 void set_update_refs_in_progress(bool in_progress); 397 void set_degenerated_gc_in_progress(bool in_progress); 398 void set_full_gc_in_progress(bool in_progress); 399 void set_full_gc_move_in_progress(bool in_progress); 400 void set_has_forwarded_objects(bool cond); 401 void set_concurrent_strong_root_in_progress(bool cond); 402 void set_concurrent_weak_root_in_progress(bool cond); 403 404 void set_aging_cycle(bool cond); 405 406 inline bool is_stable() const; 407 inline bool is_idle() const; 408 inline bool has_evacuation_reserve_quantities() const; 409 inline bool is_concurrent_mark_in_progress() const; 410 inline bool is_concurrent_young_mark_in_progress() const; 411 inline bool is_concurrent_old_mark_in_progress() const; 412 inline bool is_update_refs_in_progress() const; 413 inline bool is_evacuation_in_progress() const; 414 inline bool is_degenerated_gc_in_progress() const; 415 inline bool is_full_gc_in_progress() const; 416 inline bool is_full_gc_move_in_progress() const; 417 inline bool has_forwarded_objects() const; 418 419 inline bool is_stw_gc_in_progress() const; 420 inline bool is_concurrent_strong_root_in_progress() const; 421 inline bool is_concurrent_weak_root_in_progress() const; 422 bool is_prepare_for_old_mark_in_progress() const; 423 inline bool is_aging_cycle() const; 424 425 inline void clear_promotion_potential() { _promotion_potential = 0; }; 426 inline void set_promotion_potential(size_t val) { _promotion_potential = val; }; 427 inline size_t get_promotion_potential() { return _promotion_potential; }; 428 429 inline void set_pad_for_promote_in_place(size_t pad) { _pad_for_promote_in_place = pad; } 430 inline size_t get_pad_for_promote_in_place() { return _pad_for_promote_in_place; } 431 432 inline void reserve_promotable_humongous_regions(size_t region_count) { _promotable_humongous_regions = region_count; } 433 inline void reserve_promotable_regular_regions(size_t region_count) { _regular_regions_promoted_in_place = region_count; } 434 435 inline size_t get_promotable_humongous_regions() { return _promotable_humongous_regions; } 436 inline size_t get_regular_regions_promoted_in_place() { return _regular_regions_promoted_in_place; } 437 438 // Returns previous value 439 inline size_t set_promoted_reserve(size_t new_val); 440 inline size_t get_promoted_reserve() const; 441 inline void augment_promo_reserve(size_t increment); 442 443 inline void reset_promoted_expended(); 444 inline size_t expend_promoted(size_t increment); 445 inline size_t unexpend_promoted(size_t decrement); 446 inline size_t get_promoted_expended(); 447 448 // Returns previous value 449 inline size_t set_old_evac_reserve(size_t new_val); 450 inline size_t get_old_evac_reserve() const; 451 inline void augment_old_evac_reserve(size_t increment); 452 453 // Returns previous value 454 inline size_t set_young_evac_reserve(size_t new_val); 455 inline size_t get_young_evac_reserve() const; 456 457 // Return the age census object for young gen (in generational mode) 458 inline ShenandoahAgeCensus* age_census() const; 459 460 private: 461 void manage_satb_barrier(bool active); 462 463 enum CancelState { 464 // Normal state. GC has not been cancelled and is open for cancellation. 465 // Worker threads can suspend for safepoint. 466 CANCELLABLE, 467 468 // GC has been cancelled. Worker threads can not suspend for 469 // safepoint but must finish their work as soon as possible. 470 CANCELLED 471 }; 472 473 double _cancel_requested_time; 474 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc; 475 476 // Returns true if cancel request was successfully communicated. 477 // Returns false if some other thread already communicated cancel 478 // request. A true return value does not mean GC has been 479 // cancelled, only that the process of cancelling GC has begun. 480 bool try_cancel_gc(); 481 482 public: 483 inline bool cancelled_gc() const; 484 inline bool check_cancelled_gc_and_yield(bool sts_active = true); 485 486 inline void clear_cancelled_gc(bool clear_oom_handler = true); 487 488 void cancel_concurrent_mark(); 489 void cancel_gc(GCCause::Cause cause); 490 491 public: 492 // Elastic heap support 493 void entry_uncommit(double shrink_before, size_t shrink_until); 494 void op_uncommit(double shrink_before, size_t shrink_until); 495 496 private: 497 // GC support 498 // Evacuation 499 void evacuate_collection_set(bool concurrent); 500 // Concurrent root processing 501 void prepare_concurrent_roots(); 502 void finish_concurrent_roots(); 503 // Concurrent class unloading support 504 void do_class_unloading(); 505 // Reference updating 506 void prepare_update_heap_references(bool concurrent); 507 void update_heap_references(bool concurrent); 508 // Final update region states 509 void update_heap_region_states(bool concurrent); 510 511 void rendezvous_threads(); 512 void recycle_trash(); 513 public: 514 void rebuild_free_set(bool concurrent); 515 void notify_gc_progress(); 516 void notify_gc_no_progress(); 517 size_t get_gc_no_progress_count() const; 518 519 // 520 // Mark support 521 private: 522 ShenandoahYoungGeneration* _young_generation; 523 ShenandoahGeneration* _global_generation; 524 ShenandoahOldGeneration* _old_generation; 525 526 ShenandoahControlThread* _control_thread; 527 ShenandoahRegulatorThread* _regulator_thread; 528 ShenandoahCollectorPolicy* _shenandoah_policy; 529 ShenandoahMode* _gc_mode; 530 ShenandoahFreeSet* _free_set; 531 ShenandoahPacer* _pacer; 532 ShenandoahVerifier* _verifier; 533 534 ShenandoahPhaseTimings* _phase_timings; 535 ShenandoahEvacuationTracker* _evac_tracker; 536 ShenandoahMmuTracker _mmu_tracker; 537 ShenandoahGenerationSizer _generation_sizer; 538 539 ShenandoahRegulatorThread* regulator_thread() { return _regulator_thread; } 540 541 public: 542 ShenandoahControlThread* control_thread() { return _control_thread; } 543 ShenandoahYoungGeneration* young_generation() const { return _young_generation; } 544 ShenandoahGeneration* global_generation() const { return _global_generation; } 545 ShenandoahOldGeneration* old_generation() const { return _old_generation; } 546 ShenandoahGeneration* generation_for(ShenandoahAffiliation affiliation) const; 547 const ShenandoahGenerationSizer* generation_sizer() const { return &_generation_sizer; } 548 549 size_t max_size_for(ShenandoahGeneration* generation) const; 550 size_t min_size_for(ShenandoahGeneration* generation) const; 551 552 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; } 553 ShenandoahMode* mode() const { return _gc_mode; } 554 ShenandoahFreeSet* free_set() const { return _free_set; } 555 ShenandoahPacer* pacer() const { return _pacer; } 556 557 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; } 558 ShenandoahEvacuationTracker* evac_tracker() const { return _evac_tracker; } 559 560 void on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation); 561 void on_cycle_end(ShenandoahGeneration* generation); 562 563 ShenandoahVerifier* verifier(); 564 565 // ---------- VM subsystem bindings 566 // 567 private: 568 ShenandoahMonitoringSupport* _monitoring_support; 569 MemoryPool* _memory_pool; 570 MemoryPool* _young_gen_memory_pool; 571 MemoryPool* _old_gen_memory_pool; 572 573 GCMemoryManager _stw_memory_manager; 574 GCMemoryManager _cycle_memory_manager; 575 ConcurrentGCTimer* _gc_timer; 576 SoftRefPolicy _soft_ref_policy; 577 578 // For exporting to SA 579 int _log_min_obj_alignment_in_bytes; 580 public: 581 ShenandoahMonitoringSupport* monitoring_support() const { return _monitoring_support; } 582 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; } 583 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; } 584 SoftRefPolicy* soft_ref_policy() override { return &_soft_ref_policy; } 585 586 GrowableArray<GCMemoryManager*> memory_managers() override; 587 GrowableArray<MemoryPool*> memory_pools() override; 588 MemoryUsage memory_usage() override; 589 GCTracer* tracer(); 590 ConcurrentGCTimer* gc_timer() const; 591 592 // ---------- Class Unloading 593 // 594 private: 595 ShenandoahSharedFlag _is_aging_cycle; 596 ShenandoahSharedFlag _unload_classes; 597 ShenandoahUnload _unloader; 598 599 public: 600 void set_unload_classes(bool uc); 601 bool unload_classes() const; 602 603 // Perform STW class unloading and weak root cleaning 604 void parallel_cleaning(bool full_gc); 605 606 private: 607 void stw_unload_classes(bool full_gc); 608 void stw_process_weak_roots(bool full_gc); 609 void stw_weak_refs(bool full_gc); 610 611 inline void assert_lock_for_affiliation(ShenandoahAffiliation orig_affiliation, 612 ShenandoahAffiliation new_affiliation); 613 614 // Heap iteration support 615 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops); 616 bool prepare_aux_bitmap_for_iteration(); 617 void reclaim_aux_bitmap_for_iteration(); 618 619 // ---------- Generic interface hooks 620 // Minor things that super-interface expects us to implement to play nice with 621 // the rest of runtime. Some of the things here are not required to be implemented, 622 // and can be stubbed out. 623 // 624 public: 625 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false); 626 627 inline bool is_in(const void* p) const override; 628 629 inline bool is_in_active_generation(oop obj) const; 630 inline bool is_in_young(const void* p) const; 631 inline bool is_in_old(const void* p) const; 632 inline bool is_old(oop pobj) const; 633 634 inline ShenandoahAffiliation region_affiliation(const ShenandoahHeapRegion* r); 635 inline void set_affiliation(ShenandoahHeapRegion* r, ShenandoahAffiliation new_affiliation); 636 637 inline ShenandoahAffiliation region_affiliation(size_t index); 638 639 bool requires_barriers(stackChunkOop obj) const override; 640 641 MemRegion reserved_region() const { return _reserved; } 642 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); } 643 644 void collect(GCCause::Cause cause) override; 645 void do_full_collection(bool clear_all_soft_refs) override; 646 647 // Used for parsing heap during error printing 648 HeapWord* block_start(const void* addr) const; 649 bool block_is_obj(const HeapWord* addr) const; 650 bool print_location(outputStream* st, void* addr) const override; 651 652 // Used for native heap walkers: heap dumpers, mostly 653 void object_iterate(ObjectClosure* cl) override; 654 // Parallel heap iteration support 655 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override; 656 657 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 658 void keep_alive(oop obj) override; 659 660 // ---------- Safepoint interface hooks 661 // 662 public: 663 void safepoint_synchronize_begin() override; 664 void safepoint_synchronize_end() override; 665 666 // ---------- Code roots handling hooks 667 // 668 public: 669 void register_nmethod(nmethod* nm) override; 670 void unregister_nmethod(nmethod* nm) override; 671 void verify_nmethod(nmethod* nm) override {} 672 673 // ---------- Pinning hooks 674 // 675 public: 676 // Shenandoah supports per-object (per-region) pinning 677 void pin_object(JavaThread* thread, oop obj) override; 678 void unpin_object(JavaThread* thread, oop obj) override; 679 680 void sync_pinned_region_status(); 681 void assert_pinned_region_status() NOT_DEBUG_RETURN; 682 683 // ---------- Concurrent Stack Processing support 684 // 685 public: 686 bool uses_stack_watermark_barrier() const override { return true; } 687 688 // ---------- Allocation support 689 // 690 private: 691 // How many bytes to transfer between old and young after we have finished recycling collection set regions? 692 size_t _old_regions_surplus; 693 size_t _old_regions_deficit; 694 695 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region, bool is_promotion); 696 697 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size); 698 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size); 699 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size); 700 701 inline HeapWord* allocate_from_plab(Thread* thread, size_t size, bool is_promotion); 702 HeapWord* allocate_from_plab_slow(Thread* thread, size_t size, bool is_promotion); 703 HeapWord* allocate_new_plab(size_t min_size, size_t word_size, size_t* actual_size); 704 705 public: 706 HeapWord* allocate_memory(ShenandoahAllocRequest& request, bool is_promotion); 707 HeapWord* mem_allocate(size_t size, bool* what) override; 708 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 709 size_t size, 710 Metaspace::MetadataType mdtype) override; 711 712 void notify_mutator_alloc_words(size_t words, size_t waste); 713 714 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override; 715 size_t tlab_capacity(Thread *thr) const override; 716 size_t unsafe_max_tlab_alloc(Thread *thread) const override; 717 size_t max_tlab_size() const override; 718 size_t tlab_used(Thread* ignored) const override; 719 720 void ensure_parsability(bool retire_labs) override; 721 722 void labs_make_parsable(); 723 void tlabs_retire(bool resize); 724 void gclabs_retire(bool resize); 725 726 inline void set_old_region_surplus(size_t surplus) { _old_regions_surplus = surplus; }; 727 inline void set_old_region_deficit(size_t deficit) { _old_regions_deficit = deficit; }; 728 729 inline size_t get_old_region_surplus() { return _old_regions_surplus; }; 730 inline size_t get_old_region_deficit() { return _old_regions_deficit; }; 731 732 // ---------- Marking support 733 // 734 private: 735 ShenandoahMarkingContext* _marking_context; 736 MemRegion _bitmap_region; 737 MemRegion _aux_bitmap_region; 738 MarkBitMap _verification_bit_map; 739 MarkBitMap _aux_bit_map; 740 741 size_t _bitmap_size; 742 size_t _bitmap_regions_per_slice; 743 size_t _bitmap_bytes_per_slice; 744 745 size_t _pretouch_heap_page_size; 746 size_t _pretouch_bitmap_page_size; 747 748 bool _bitmap_region_special; 749 bool _aux_bitmap_region_special; 750 751 ShenandoahLiveData** _liveness_cache; 752 753 public: 754 inline ShenandoahMarkingContext* complete_marking_context() const; 755 inline ShenandoahMarkingContext* marking_context() const; 756 757 template<class T> 758 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl); 759 760 template<class T> 761 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 762 763 template<class T> 764 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 765 766 // SATB barriers hooks 767 inline bool requires_marking(const void* entry) const; 768 769 // Support for bitmap uncommits 770 bool commit_bitmap_slice(ShenandoahHeapRegion *r); 771 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r); 772 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false); 773 774 // Liveness caching support 775 ShenandoahLiveData* get_liveness_cache(uint worker_id); 776 void flush_liveness_cache(uint worker_id); 777 778 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; } 779 780 // ---------- Evacuation support 781 // 782 private: 783 ShenandoahCollectionSet* _collection_set; 784 ShenandoahEvacOOMHandler _oom_evac_handler; 785 ShenandoahSharedFlag _old_gen_oom_evac; 786 787 inline oop try_evacuate_object(oop src, Thread* thread, ShenandoahHeapRegion* from_region, ShenandoahAffiliation target_gen); 788 void handle_old_evacuation(HeapWord* obj, size_t words, bool promotion); 789 void handle_old_evacuation_failure(); 790 791 public: 792 void report_promotion_failure(Thread* thread, size_t size); 793 794 static address in_cset_fast_test_addr(); 795 796 ShenandoahCollectionSet* collection_set() const { return _collection_set; } 797 798 // Checks if object is in the collection set. 799 inline bool in_collection_set(oop obj) const; 800 801 // Checks if location is in the collection set. Can be interior pointer, not the oop itself. 802 inline bool in_collection_set_loc(void* loc) const; 803 804 // Evacuates or promotes object src. Returns the evacuated object, either evacuated 805 // by this thread, or by some other thread. 806 inline oop evacuate_object(oop src, Thread* thread); 807 808 // Call before/after evacuation. 809 inline void enter_evacuation(Thread* t); 810 inline void leave_evacuation(Thread* t); 811 812 inline bool clear_old_evacuation_failure(); 813 814 // ---------- Generational support 815 // 816 private: 817 RememberedScanner* _card_scan; 818 819 public: 820 inline RememberedScanner* card_scan() { return _card_scan; } 821 void clear_cards_for(ShenandoahHeapRegion* region); 822 void mark_card_as_dirty(void* location); 823 void retire_plab(PLAB* plab); 824 void retire_plab(PLAB* plab, Thread* thread); 825 void cancel_old_gc(); 826 827 void adjust_generation_sizes_for_next_cycle(size_t old_xfer_limit, size_t young_cset_regions, size_t old_cset_regions); 828 829 // ---------- Helper functions 830 // 831 public: 832 template <class T> 833 inline void conc_update_with_forwarded(T* p); 834 835 template <class T> 836 inline void update_with_forwarded(T* p); 837 838 static inline void atomic_update_oop(oop update, oop* addr, oop compare); 839 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare); 840 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare); 841 842 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare); 843 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare); 844 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare); 845 846 static inline void atomic_clear_oop( oop* addr, oop compare); 847 static inline void atomic_clear_oop(narrowOop* addr, oop compare); 848 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare); 849 850 size_t trash_humongous_region_at(ShenandoahHeapRegion *r); 851 852 static inline void increase_object_age(oop obj, uint additional_age); 853 854 // Return the object's age, or a sentinel value when the age can't 855 // necessarily be determined because of concurrent locking by the 856 // mutator 857 static inline uint get_object_age(oop obj); 858 859 void transfer_old_pointers_from_satb(); 860 861 void log_heap_status(const char *msg) const; 862 863 private: 864 void trash_cset_regions(); 865 866 // ---------- Testing helpers functions 867 // 868 private: 869 ShenandoahSharedFlag _inject_alloc_failure; 870 871 void try_inject_alloc_failure(); 872 bool should_inject_alloc_failure(); 873 }; 874 875 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP