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/shenandoahController.hpp" 40 #include "gc/shenandoah/shenandoahLock.hpp" 41 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp" 42 #include "gc/shenandoah/shenandoahEvacTracker.hpp" 43 #include "gc/shenandoah/shenandoahGenerationType.hpp" 44 #include "gc/shenandoah/shenandoahMmuTracker.hpp" 45 #include "gc/shenandoah/shenandoahPadding.hpp" 46 #include "gc/shenandoah/shenandoahScanRemembered.hpp" 47 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 48 #include "gc/shenandoah/shenandoahUnload.hpp" 49 #include "memory/metaspace.hpp" 50 #include "services/memoryManager.hpp" 51 #include "utilities/globalDefinitions.hpp" 52 #include "utilities/stack.hpp" 53 54 class ConcurrentGCTimer; 55 class ObjectIterateScanRootClosure; 56 class PLAB; 57 class ShenandoahCollectorPolicy; 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; 152 153 // Supported GC 154 friend class ShenandoahConcurrentGC; 155 friend class ShenandoahOldGC; 156 friend class ShenandoahDegenGC; 157 friend class ShenandoahFullGC; 158 friend class ShenandoahUnload; 159 160 // ---------- Locks that guard important data structures in Heap 161 // 162 private: 163 ShenandoahHeapLock _lock; 164 ShenandoahGeneration* _gc_generation; 165 166 public: 167 ShenandoahHeapLock* lock() { 168 return &_lock; 169 } 170 171 ShenandoahGeneration* active_generation() const { 172 // last or latest generation might be a better name here. 173 return _gc_generation; 174 } 175 176 void set_gc_generation(ShenandoahGeneration* generation) { 177 _gc_generation = generation; 178 } 179 180 ShenandoahHeuristics* heuristics(); 181 ShenandoahOldHeuristics* old_heuristics(); 182 ShenandoahYoungHeuristics* young_heuristics(); 183 184 bool doing_mixed_evacuations(); 185 bool is_old_bitmap_stable() const; 186 bool is_gc_generation_young() const; 187 188 // ---------- Initialization, termination, identification, printing routines 189 // 190 public: 191 static ShenandoahHeap* heap(); 192 193 const char* name() const override { return "Shenandoah"; } 194 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; } 195 196 ShenandoahHeap(ShenandoahCollectorPolicy* policy); 197 jint initialize() override; 198 void post_initialize() override; 199 void initialize_heuristics_generations(); 200 virtual void print_init_logger() const; 201 void initialize_serviceability() override; 202 203 void print_on(outputStream* st) const override; 204 void print_extended_on(outputStream *st) const override; 205 void print_tracing_info() const override; 206 void print_heap_regions_on(outputStream* st) const; 207 208 void stop() override; 209 210 void prepare_for_verify() override; 211 void verify(VerifyOption vo) override; 212 213 bool verify_generation_usage(bool verify_old, size_t old_regions, size_t old_bytes, size_t old_waste, 214 bool verify_young, size_t young_regions, size_t young_bytes, size_t young_waste); 215 216 // WhiteBox testing support. 217 bool supports_concurrent_gc_breakpoints() const override { 218 return true; 219 } 220 221 // ---------- Heap counters and metrics 222 // 223 private: 224 size_t _initial_size; 225 size_t _minimum_size; 226 227 volatile size_t _soft_max_size; 228 shenandoah_padding(0); 229 volatile size_t _committed; 230 shenandoah_padding(1); 231 232 void increase_used(const ShenandoahAllocRequest& req); 233 234 public: 235 void increase_used(ShenandoahGeneration* generation, size_t bytes); 236 void decrease_used(ShenandoahGeneration* generation, size_t bytes); 237 void increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 238 void decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 239 240 void increase_committed(size_t bytes); 241 void decrease_committed(size_t bytes); 242 243 void reset_bytes_allocated_since_gc_start(); 244 245 size_t min_capacity() const; 246 size_t max_capacity() const override; 247 size_t soft_max_capacity() const; 248 size_t initial_capacity() const; 249 size_t capacity() const override; 250 size_t used() const override; 251 size_t committed() const; 252 253 void set_soft_max_capacity(size_t v); 254 255 // ---------- Periodic Tasks 256 // 257 private: 258 void notify_heap_changed(); 259 260 public: 261 void set_forced_counters_update(bool value); 262 void handle_force_counters_update(); 263 264 // ---------- Workers handling 265 // 266 private: 267 uint _max_workers; 268 ShenandoahWorkerThreads* _workers; 269 ShenandoahWorkerThreads* _safepoint_workers; 270 271 virtual void initialize_controller(); 272 273 public: 274 uint max_workers(); 275 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN; 276 277 WorkerThreads* workers() const; 278 WorkerThreads* safepoint_workers() override; 279 280 void gc_threads_do(ThreadClosure* tcl) const override; 281 282 // ---------- Heap regions handling machinery 283 // 284 private: 285 MemRegion _heap_region; 286 bool _heap_region_special; 287 size_t _num_regions; 288 ShenandoahHeapRegion** _regions; 289 uint8_t* _affiliations; // Holds array of enum ShenandoahAffiliation, including FREE status in non-generational mode 290 ShenandoahRegionIterator _update_refs_iterator; 291 292 public: 293 294 inline HeapWord* base() const { return _heap_region.start(); } 295 296 inline size_t num_regions() const { return _num_regions; } 297 inline bool is_heap_region_special() { return _heap_region_special; } 298 299 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const; 300 inline size_t heap_region_index_containing(const void* addr) const; 301 302 inline ShenandoahHeapRegion* get_region(size_t region_idx) const; 303 304 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 305 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 306 307 inline ShenandoahMmuTracker* mmu_tracker() { return &_mmu_tracker; }; 308 309 // ---------- GC state machinery 310 // 311 // GC state describes the important parts of collector state, that may be 312 // used to make barrier selection decisions in the native and generated code. 313 // Multiple bits can be set at once. 314 // 315 // Important invariant: when GC state is zero, the heap is stable, and no barriers 316 // are required. 317 // 318 public: 319 enum GCStateBitPos { 320 // Heap has forwarded objects: needs LRB barriers. 321 HAS_FORWARDED_BITPOS = 0, 322 323 // Heap is under marking: needs SATB barriers. 324 // For generational mode, it means either young or old marking, or both. 325 MARKING_BITPOS = 1, 326 327 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED) 328 EVACUATION_BITPOS = 2, 329 330 // Heap is under updating: needs no additional barriers. 331 UPDATEREFS_BITPOS = 3, 332 333 // Heap is under weak-reference/roots processing: needs weak-LRB barriers. 334 WEAK_ROOTS_BITPOS = 4, 335 336 // Young regions are under marking, need SATB barriers. 337 YOUNG_MARKING_BITPOS = 5, 338 339 // Old regions are under marking, need SATB barriers. 340 OLD_MARKING_BITPOS = 6 341 }; 342 343 enum GCState { 344 STABLE = 0, 345 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS, 346 MARKING = 1 << MARKING_BITPOS, 347 EVACUATION = 1 << EVACUATION_BITPOS, 348 UPDATEREFS = 1 << UPDATEREFS_BITPOS, 349 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS, 350 YOUNG_MARKING = 1 << YOUNG_MARKING_BITPOS, 351 OLD_MARKING = 1 << OLD_MARKING_BITPOS 352 }; 353 354 private: 355 bool _gc_state_changed; 356 ShenandoahSharedBitmap _gc_state; 357 ShenandoahSharedFlag _heap_changed; 358 ShenandoahSharedFlag _degenerated_gc_in_progress; 359 ShenandoahSharedFlag _full_gc_in_progress; 360 ShenandoahSharedFlag _full_gc_move_in_progress; 361 ShenandoahSharedFlag _concurrent_strong_root_in_progress; 362 363 size_t _gc_no_progress_count; 364 365 // This updates the singlular, global gc state. This must happen on a safepoint. 366 void set_gc_state(uint mask, bool value); 367 368 ShenandoahAgeCensus* _age_census; // Age census used for adapting tenuring threshold in generational mode 369 370 public: 371 char gc_state() const; 372 373 // This copies the global gc state into a thread local variable for java threads. 374 // It is primarily intended to support quick access at barriers. 375 void propagate_gc_state_to_java_threads(); 376 377 // This is public to support assertions that the state hasn't been changed off of 378 // a safepoint and that any changes were propagated to java threads after the safepoint. 379 bool has_gc_state_changed() const { return _gc_state_changed; } 380 381 // Returns true if allocations have occurred in new regions or if regions have been 382 // uncommitted since the previous calls. This call will reset the flag to false. 383 bool has_changed() { 384 return _heap_changed.try_unset(); 385 } 386 387 void set_concurrent_young_mark_in_progress(bool in_progress); 388 void set_concurrent_old_mark_in_progress(bool in_progress); 389 void set_evacuation_in_progress(bool in_progress); 390 void set_update_refs_in_progress(bool in_progress); 391 void set_degenerated_gc_in_progress(bool in_progress); 392 void set_full_gc_in_progress(bool in_progress); 393 void set_full_gc_move_in_progress(bool in_progress); 394 void set_has_forwarded_objects(bool cond); 395 void set_concurrent_strong_root_in_progress(bool cond); 396 void set_concurrent_weak_root_in_progress(bool cond); 397 398 void set_aging_cycle(bool cond); 399 400 inline bool is_stable() const; 401 inline bool is_idle() const; 402 403 inline bool is_concurrent_mark_in_progress() const; 404 inline bool is_concurrent_young_mark_in_progress() const; 405 inline bool is_concurrent_old_mark_in_progress() const; 406 inline bool is_update_refs_in_progress() const; 407 inline bool is_evacuation_in_progress() const; 408 inline bool is_degenerated_gc_in_progress() const; 409 inline bool is_full_gc_in_progress() const; 410 inline bool is_full_gc_move_in_progress() const; 411 inline bool has_forwarded_objects() const; 412 413 inline bool is_stw_gc_in_progress() const; 414 inline bool is_concurrent_strong_root_in_progress() const; 415 inline bool is_concurrent_weak_root_in_progress() const; 416 bool is_prepare_for_old_mark_in_progress() const; 417 inline bool is_aging_cycle() const; 418 419 // Return the age census object for young gen (in generational mode) 420 inline ShenandoahAgeCensus* age_census() const; 421 422 private: 423 void manage_satb_barrier(bool active); 424 425 enum CancelState { 426 // Normal state. GC has not been cancelled and is open for cancellation. 427 // Worker threads can suspend for safepoint. 428 CANCELLABLE, 429 430 // GC has been cancelled. Worker threads can not suspend for 431 // safepoint but must finish their work as soon as possible. 432 CANCELLED 433 }; 434 435 double _cancel_requested_time; 436 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc; 437 438 // Returns true if cancel request was successfully communicated. 439 // Returns false if some other thread already communicated cancel 440 // request. A true return value does not mean GC has been 441 // cancelled, only that the process of cancelling GC has begun. 442 bool try_cancel_gc(); 443 444 public: 445 inline bool cancelled_gc() const; 446 inline bool check_cancelled_gc_and_yield(bool sts_active = true); 447 448 inline void clear_cancelled_gc(bool clear_oom_handler = true); 449 450 void cancel_concurrent_mark(); 451 void cancel_gc(GCCause::Cause cause); 452 453 public: 454 // These will uncommit empty regions if heap::committed > shrink_until 455 // and there exists at least one region which was made empty before shrink_before. 456 void maybe_uncommit(double shrink_before, size_t shrink_until); 457 void op_uncommit(double shrink_before, size_t shrink_until); 458 459 // Returns true if the soft maximum heap has been changed using management APIs. 460 bool check_soft_max_changed(); 461 462 private: 463 // GC support 464 // Evacuation 465 void evacuate_collection_set(bool concurrent); 466 // Concurrent root processing 467 void prepare_concurrent_roots(); 468 void finish_concurrent_roots(); 469 // Concurrent class unloading support 470 void do_class_unloading(); 471 // Reference updating 472 void prepare_update_heap_references(bool concurrent); 473 void update_heap_references(bool concurrent); 474 // Final update region states 475 void update_heap_region_states(bool concurrent); 476 477 void rendezvous_threads(); 478 void recycle_trash(); 479 public: 480 void rebuild_free_set(bool concurrent); 481 void notify_gc_progress(); 482 void notify_gc_no_progress(); 483 size_t get_gc_no_progress_count() const; 484 485 // 486 // Mark support 487 private: 488 ShenandoahYoungGeneration* _young_generation; 489 ShenandoahGeneration* _global_generation; 490 ShenandoahOldGeneration* _old_generation; 491 492 protected: 493 ShenandoahController* _control_thread; 494 495 private: 496 ShenandoahCollectorPolicy* _shenandoah_policy; 497 ShenandoahMode* _gc_mode; 498 ShenandoahFreeSet* _free_set; 499 ShenandoahPacer* _pacer; 500 ShenandoahVerifier* _verifier; 501 502 ShenandoahPhaseTimings* _phase_timings; 503 ShenandoahEvacuationTracker* _evac_tracker; 504 ShenandoahMmuTracker _mmu_tracker; 505 ShenandoahGenerationSizer _generation_sizer; 506 507 public: 508 ShenandoahController* control_thread() { return _control_thread; } 509 510 ShenandoahYoungGeneration* young_generation() const { return _young_generation; } 511 ShenandoahGeneration* global_generation() const { return _global_generation; } 512 ShenandoahOldGeneration* old_generation() const { return _old_generation; } 513 ShenandoahGeneration* generation_for(ShenandoahAffiliation affiliation) const; 514 const ShenandoahGenerationSizer* generation_sizer() const { return &_generation_sizer; } 515 516 size_t max_size_for(ShenandoahGeneration* generation) const; 517 size_t min_size_for(ShenandoahGeneration* generation) const; 518 519 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; } 520 ShenandoahMode* mode() const { return _gc_mode; } 521 ShenandoahFreeSet* free_set() const { return _free_set; } 522 ShenandoahPacer* pacer() const { return _pacer; } 523 524 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; } 525 ShenandoahEvacuationTracker* evac_tracker() const { return _evac_tracker; } 526 527 void on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation); 528 void on_cycle_end(ShenandoahGeneration* generation); 529 530 ShenandoahVerifier* verifier(); 531 532 // ---------- VM subsystem bindings 533 // 534 private: 535 ShenandoahMonitoringSupport* _monitoring_support; 536 MemoryPool* _memory_pool; 537 GCMemoryManager _stw_memory_manager; 538 GCMemoryManager _cycle_memory_manager; 539 ConcurrentGCTimer* _gc_timer; 540 // For exporting to SA 541 int _log_min_obj_alignment_in_bytes; 542 public: 543 ShenandoahMonitoringSupport* monitoring_support() const { return _monitoring_support; } 544 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; } 545 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; } 546 547 GrowableArray<GCMemoryManager*> memory_managers() override; 548 GrowableArray<MemoryPool*> memory_pools() override; 549 MemoryUsage memory_usage() override; 550 GCTracer* tracer(); 551 ConcurrentGCTimer* gc_timer() const; 552 553 // ---------- Class Unloading 554 // 555 private: 556 ShenandoahSharedFlag _is_aging_cycle; 557 ShenandoahSharedFlag _unload_classes; 558 ShenandoahUnload _unloader; 559 560 public: 561 void set_unload_classes(bool uc); 562 bool unload_classes() const; 563 564 // Perform STW class unloading and weak root cleaning 565 void parallel_cleaning(bool full_gc); 566 567 private: 568 void stw_unload_classes(bool full_gc); 569 void stw_process_weak_roots(bool full_gc); 570 void stw_weak_refs(bool full_gc); 571 572 inline void assert_lock_for_affiliation(ShenandoahAffiliation orig_affiliation, 573 ShenandoahAffiliation new_affiliation); 574 575 // Heap iteration support 576 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops); 577 bool prepare_aux_bitmap_for_iteration(); 578 void reclaim_aux_bitmap_for_iteration(); 579 580 // ---------- Generic interface hooks 581 // Minor things that super-interface expects us to implement to play nice with 582 // the rest of runtime. Some of the things here are not required to be implemented, 583 // and can be stubbed out. 584 // 585 public: 586 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false); 587 588 inline bool is_in(const void* p) const override; 589 590 inline bool is_in_active_generation(oop obj) const; 591 inline bool is_in_young(const void* p) const; 592 inline bool is_in_old(const void* p) const; 593 inline bool is_old(oop pobj) const; 594 595 inline ShenandoahAffiliation region_affiliation(const ShenandoahHeapRegion* r); 596 inline void set_affiliation(ShenandoahHeapRegion* r, ShenandoahAffiliation new_affiliation); 597 598 inline ShenandoahAffiliation region_affiliation(size_t index); 599 600 bool requires_barriers(stackChunkOop obj) const override; 601 602 MemRegion reserved_region() const { return _reserved; } 603 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); } 604 605 void collect(GCCause::Cause cause) override; 606 void do_full_collection(bool clear_all_soft_refs) override; 607 608 // Used for parsing heap during error printing 609 HeapWord* block_start(const void* addr) const; 610 bool block_is_obj(const HeapWord* addr) const; 611 bool print_location(outputStream* st, void* addr) const override; 612 613 // Used for native heap walkers: heap dumpers, mostly 614 void object_iterate(ObjectClosure* cl) override; 615 // Parallel heap iteration support 616 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override; 617 618 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 619 void keep_alive(oop obj) override; 620 621 // ---------- Safepoint interface hooks 622 // 623 public: 624 void safepoint_synchronize_begin() override; 625 void safepoint_synchronize_end() override; 626 627 // ---------- Code roots handling hooks 628 // 629 public: 630 void register_nmethod(nmethod* nm) override; 631 void unregister_nmethod(nmethod* nm) override; 632 void verify_nmethod(nmethod* nm) override {} 633 634 // ---------- Pinning hooks 635 // 636 public: 637 // Shenandoah supports per-object (per-region) pinning 638 void pin_object(JavaThread* thread, oop obj) override; 639 void unpin_object(JavaThread* thread, oop obj) override; 640 641 void sync_pinned_region_status(); 642 void assert_pinned_region_status() NOT_DEBUG_RETURN; 643 644 // ---------- Concurrent Stack Processing support 645 // 646 public: 647 bool uses_stack_watermark_barrier() const override { return true; } 648 649 // ---------- Allocation support 650 // 651 private: 652 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region, bool is_promotion); 653 654 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size); 655 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size); 656 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size); 657 658 inline HeapWord* allocate_from_plab(Thread* thread, size_t size, bool is_promotion); 659 HeapWord* allocate_from_plab_slow(Thread* thread, size_t size, bool is_promotion); 660 HeapWord* allocate_new_plab(size_t min_size, size_t word_size, size_t* actual_size); 661 662 public: 663 HeapWord* allocate_memory(ShenandoahAllocRequest& request, bool is_promotion); 664 HeapWord* mem_allocate(size_t size, bool* what) override; 665 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 666 size_t size, 667 Metaspace::MetadataType mdtype) override; 668 669 void notify_mutator_alloc_words(size_t words, size_t waste); 670 671 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override; 672 size_t tlab_capacity(Thread *thr) const override; 673 size_t unsafe_max_tlab_alloc(Thread *thread) const override; 674 size_t max_tlab_size() const override; 675 size_t tlab_used(Thread* ignored) const override; 676 677 void ensure_parsability(bool retire_labs) override; 678 679 void labs_make_parsable(); 680 void tlabs_retire(bool resize); 681 void gclabs_retire(bool resize); 682 683 // ---------- Marking support 684 // 685 private: 686 ShenandoahMarkingContext* _marking_context; 687 MemRegion _bitmap_region; 688 MemRegion _aux_bitmap_region; 689 MarkBitMap _verification_bit_map; 690 MarkBitMap _aux_bit_map; 691 692 size_t _bitmap_size; 693 size_t _bitmap_regions_per_slice; 694 size_t _bitmap_bytes_per_slice; 695 696 size_t _pretouch_heap_page_size; 697 size_t _pretouch_bitmap_page_size; 698 699 bool _bitmap_region_special; 700 bool _aux_bitmap_region_special; 701 702 ShenandoahLiveData** _liveness_cache; 703 704 public: 705 inline ShenandoahMarkingContext* complete_marking_context() const; 706 inline ShenandoahMarkingContext* marking_context() const; 707 708 template<class T> 709 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl); 710 711 template<class T> 712 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 713 714 template<class T> 715 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 716 717 // SATB barriers hooks 718 inline bool requires_marking(const void* entry) const; 719 720 // Support for bitmap uncommits 721 bool commit_bitmap_slice(ShenandoahHeapRegion *r); 722 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r); 723 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false); 724 725 // Liveness caching support 726 ShenandoahLiveData* get_liveness_cache(uint worker_id); 727 void flush_liveness_cache(uint worker_id); 728 729 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; } 730 731 // ---------- Evacuation support 732 // 733 private: 734 ShenandoahCollectionSet* _collection_set; 735 ShenandoahEvacOOMHandler _oom_evac_handler; 736 737 oop try_evacuate_object(oop src, Thread* thread, ShenandoahHeapRegion* from_region, ShenandoahAffiliation target_gen); 738 public: 739 740 static address in_cset_fast_test_addr(); 741 742 ShenandoahCollectionSet* collection_set() const { return _collection_set; } 743 744 // Checks if object is in the collection set. 745 inline bool in_collection_set(oop obj) const; 746 747 // Checks if location is in the collection set. Can be interior pointer, not the oop itself. 748 inline bool in_collection_set_loc(void* loc) const; 749 750 // Evacuates or promotes object src. Returns the evacuated object, either evacuated 751 // by this thread, or by some other thread. 752 inline oop evacuate_object(oop src, Thread* thread); 753 754 // Call before/after evacuation. 755 inline void enter_evacuation(Thread* t); 756 inline void leave_evacuation(Thread* t); 757 758 // ---------- Generational support 759 // 760 private: 761 RememberedScanner* _card_scan; 762 763 public: 764 inline RememberedScanner* card_scan() { return _card_scan; } 765 void clear_cards_for(ShenandoahHeapRegion* region); 766 void mark_card_as_dirty(void* location); 767 void retire_plab(PLAB* plab); 768 void retire_plab(PLAB* plab, Thread* thread); 769 void cancel_old_gc(); 770 771 // ---------- Helper functions 772 // 773 public: 774 template <class T> 775 inline void conc_update_with_forwarded(T* p); 776 777 template <class T> 778 inline void update_with_forwarded(T* p); 779 780 static inline void atomic_update_oop(oop update, oop* addr, oop compare); 781 static inline void atomic_update_oop(oop update, narrowOop* addr, oop compare); 782 static inline void atomic_update_oop(oop update, narrowOop* addr, narrowOop compare); 783 784 static inline bool atomic_update_oop_check(oop update, oop* addr, oop compare); 785 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, oop compare); 786 static inline bool atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare); 787 788 static inline void atomic_clear_oop( oop* addr, oop compare); 789 static inline void atomic_clear_oop(narrowOop* addr, oop compare); 790 static inline void atomic_clear_oop(narrowOop* addr, narrowOop compare); 791 792 size_t trash_humongous_region_at(ShenandoahHeapRegion *r); 793 794 static inline void increase_object_age(oop obj, uint additional_age); 795 796 // Return the object's age, or a sentinel value when the age can't 797 // necessarily be determined because of concurrent locking by the 798 // mutator 799 static inline uint get_object_age(oop obj); 800 801 void transfer_old_pointers_from_satb(); 802 803 void log_heap_status(const char *msg) const; 804 805 private: 806 void trash_cset_regions(); 807 808 // ---------- Testing helpers functions 809 // 810 private: 811 ShenandoahSharedFlag _inject_alloc_failure; 812 813 void try_inject_alloc_failure(); 814 bool should_inject_alloc_failure(); 815 }; 816 817 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP