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/markBitMap.hpp" 31 #include "gc/shared/softRefPolicy.hpp" 32 #include "gc/shared/collectedHeap.hpp" 33 #include "gc/shenandoah/heuristics/shenandoahSpaceInfo.hpp" 34 #include "gc/shenandoah/shenandoahAllocRequest.hpp" 35 #include "gc/shenandoah/shenandoahAsserts.hpp" 36 #include "gc/shenandoah/shenandoahController.hpp" 37 #include "gc/shenandoah/shenandoahLock.hpp" 38 #include "gc/shenandoah/shenandoahEvacOOMHandler.hpp" 39 #include "gc/shenandoah/shenandoahEvacTracker.hpp" 40 #include "gc/shenandoah/shenandoahGenerationType.hpp" 41 #include "gc/shenandoah/shenandoahGenerationSizer.hpp" 42 #include "gc/shenandoah/shenandoahMmuTracker.hpp" 43 #include "gc/shenandoah/mode/shenandoahMode.hpp" 44 #include "gc/shenandoah/shenandoahPadding.hpp" 45 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 46 #include "gc/shenandoah/shenandoahUnload.hpp" 47 #include "memory/metaspace.hpp" 48 #include "services/memoryManager.hpp" 49 #include "utilities/globalDefinitions.hpp" 50 #include "utilities/stack.hpp" 51 52 class ConcurrentGCTimer; 53 class ObjectIterateScanRootClosure; 54 class ShenandoahCollectorPolicy; 55 class ShenandoahGCSession; 56 class ShenandoahGCStateResetter; 57 class ShenandoahGeneration; 58 class ShenandoahYoungGeneration; 59 class ShenandoahOldGeneration; 60 class ShenandoahHeuristics; 61 class ShenandoahMarkingContext; 62 class ShenandoahMode; 63 class ShenandoahPhaseTimings; 64 class ShenandoahHeap; 65 class ShenandoahHeapRegion; 66 class ShenandoahHeapRegionClosure; 67 class ShenandoahCollectionSet; 68 class ShenandoahFreeSet; 69 class ShenandoahConcurrentMark; 70 class ShenandoahFullGC; 71 class ShenandoahMonitoringSupport; 72 class ShenandoahPacer; 73 class ShenandoahReferenceProcessor; 74 class ShenandoahVerifier; 75 class ShenandoahWorkerThreads; 76 class VMStructs; 77 78 // Used for buffering per-region liveness data. 79 // Needed since ShenandoahHeapRegion uses atomics to update liveness. 80 // The ShenandoahHeap array has max-workers elements, each of which is an array of 81 // uint16_t * max_regions. The choice of uint16_t is not accidental: 82 // there is a tradeoff between static/dynamic footprint that translates 83 // into cache pressure (which is already high during marking), and 84 // too many atomic updates. uint32_t is too large, uint8_t is too small. 85 typedef uint16_t ShenandoahLiveData; 86 #define SHENANDOAH_LIVEDATA_MAX ((ShenandoahLiveData)-1) 87 88 class ShenandoahRegionIterator : public StackObj { 89 private: 90 ShenandoahHeap* _heap; 91 92 shenandoah_padding(0); 93 volatile size_t _index; 94 shenandoah_padding(1); 95 96 // No implicit copying: iterators should be passed by reference to capture the state 97 NONCOPYABLE(ShenandoahRegionIterator); 98 99 public: 100 ShenandoahRegionIterator(); 101 ShenandoahRegionIterator(ShenandoahHeap* heap); 102 103 // Reset iterator to default state 104 void reset(); 105 106 // Returns next region, or null if there are no more regions. 107 // This is multi-thread-safe. 108 inline ShenandoahHeapRegion* next(); 109 110 // This is *not* MT safe. However, in the absence of multithreaded access, it 111 // can be used to determine if there is more work to do. 112 bool has_next() const; 113 }; 114 115 class ShenandoahHeapRegionClosure : public StackObj { 116 public: 117 virtual void heap_region_do(ShenandoahHeapRegion* r) = 0; 118 virtual bool is_thread_safe() { return false; } 119 }; 120 121 typedef ShenandoahLock ShenandoahHeapLock; 122 typedef ShenandoahLocker ShenandoahHeapLocker; 123 typedef Stack<oop, mtGC> ShenandoahScanObjectStack; 124 125 class ShenandoahSynchronizePinnedRegionStates : public ShenandoahHeapRegionClosure { 126 private: 127 ShenandoahHeapLock* const _lock; 128 129 public: 130 ShenandoahSynchronizePinnedRegionStates(); 131 132 void heap_region_do(ShenandoahHeapRegion* r) override; 133 bool is_thread_safe() override { return true; } 134 }; 135 136 // Shenandoah GC is low-pause concurrent GC that uses Brooks forwarding pointers 137 // to encode forwarding data. See BrooksPointer for details on forwarding data encoding. 138 // See ShenandoahControlThread for GC cycle structure. 139 // 140 class ShenandoahHeap : public CollectedHeap { 141 friend class ShenandoahAsserts; 142 friend class VMStructs; 143 friend class ShenandoahGCSession; 144 friend class ShenandoahGCStateResetter; 145 friend class ShenandoahParallelObjectIterator; 146 friend class ShenandoahSafepoint; 147 148 // Supported GC 149 friend class ShenandoahConcurrentGC; 150 friend class ShenandoahOldGC; 151 friend class ShenandoahDegenGC; 152 friend class ShenandoahFullGC; 153 friend class ShenandoahUnload; 154 155 // ---------- Locks that guard important data structures in Heap 156 // 157 private: 158 ShenandoahHeapLock _lock; 159 160 // Indicates the generation whose collection is in 161 // progress. Mutator threads aren't allowed to read 162 // this field. 163 ShenandoahGeneration* _gc_generation; 164 165 // This is set and cleared by only the VMThread 166 // at each STW pause (safepoint) to the value seen in 167 // _gc_generation. This allows the value to be always consistently 168 // seen by all mutators as well as all GC worker threads. 169 // In that sense, it's a stable snapshot of _gc_generation that is 170 // updated at each STW pause associated with a ShenandoahVMOp. 171 ShenandoahGeneration* _active_generation; 172 173 public: 174 ShenandoahHeapLock* lock() { 175 return &_lock; 176 } 177 178 ShenandoahGeneration* gc_generation() const { 179 // We don't want this field read by a mutator thread 180 assert(!Thread::current()->is_Java_thread(), "Not allowed"); 181 // value of _gc_generation field, see above 182 return _gc_generation; 183 } 184 185 ShenandoahGeneration* active_generation() const { 186 // value of _active_generation field, see above 187 return _active_generation; 188 } 189 190 // Set the _gc_generation field 191 void set_gc_generation(ShenandoahGeneration* generation); 192 193 // Copy the value in the _gc_generation field into 194 // the _active_generation field: can only be called at 195 // a safepoint by the VMThread. 196 void set_active_generation(); 197 198 ShenandoahHeuristics* heuristics(); 199 200 // ---------- Initialization, termination, identification, printing routines 201 // 202 public: 203 static ShenandoahHeap* heap(); 204 205 const char* name() const override { return "Shenandoah"; } 206 ShenandoahHeap::Name kind() const override { return CollectedHeap::Shenandoah; } 207 208 ShenandoahHeap(ShenandoahCollectorPolicy* policy); 209 jint initialize() override; 210 void post_initialize() override; 211 void initialize_mode(); 212 virtual void initialize_heuristics(); 213 virtual void print_init_logger() const; 214 void initialize_serviceability() override; 215 216 void print_on(outputStream* st) const override; 217 void print_extended_on(outputStream *st) const override; 218 void print_tracing_info() const override; 219 void print_heap_regions_on(outputStream* st) const; 220 221 void stop() override; 222 223 void prepare_for_verify() override; 224 void verify(VerifyOption vo) override; 225 226 // WhiteBox testing support. 227 bool supports_concurrent_gc_breakpoints() const override { 228 return true; 229 } 230 231 // ---------- Heap counters and metrics 232 // 233 private: 234 size_t _initial_size; 235 size_t _minimum_size; 236 237 volatile size_t _soft_max_size; 238 shenandoah_padding(0); 239 volatile size_t _committed; 240 shenandoah_padding(1); 241 242 void increase_used(const ShenandoahAllocRequest& req); 243 244 public: 245 void increase_used(ShenandoahGeneration* generation, size_t bytes); 246 void decrease_used(ShenandoahGeneration* generation, size_t bytes); 247 void increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 248 void decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes); 249 250 void increase_committed(size_t bytes); 251 void decrease_committed(size_t bytes); 252 253 void reset_bytes_allocated_since_gc_start(); 254 255 size_t min_capacity() const; 256 size_t max_capacity() const override; 257 size_t soft_max_capacity() const; 258 size_t initial_capacity() const; 259 size_t capacity() const override; 260 size_t used() const override; 261 size_t committed() const; 262 263 void set_soft_max_capacity(size_t v); 264 265 // ---------- Periodic Tasks 266 // 267 private: 268 void notify_heap_changed(); 269 270 public: 271 void set_forced_counters_update(bool value); 272 void handle_force_counters_update(); 273 274 // ---------- Workers handling 275 // 276 private: 277 uint _max_workers; 278 ShenandoahWorkerThreads* _workers; 279 ShenandoahWorkerThreads* _safepoint_workers; 280 281 virtual void initialize_controller(); 282 283 public: 284 uint max_workers(); 285 void assert_gc_workers(uint nworker) NOT_DEBUG_RETURN; 286 287 WorkerThreads* workers() const; 288 WorkerThreads* safepoint_workers() override; 289 290 void gc_threads_do(ThreadClosure* tcl) const override; 291 292 // ---------- Heap regions handling machinery 293 // 294 private: 295 MemRegion _heap_region; 296 bool _heap_region_special; 297 size_t _num_regions; 298 ShenandoahHeapRegion** _regions; 299 uint8_t* _affiliations; // Holds array of enum ShenandoahAffiliation, including FREE status in non-generational mode 300 301 public: 302 303 inline HeapWord* base() const { return _heap_region.start(); } 304 305 inline size_t num_regions() const { return _num_regions; } 306 inline bool is_heap_region_special() { return _heap_region_special; } 307 308 inline ShenandoahHeapRegion* heap_region_containing(const void* addr) const; 309 inline size_t heap_region_index_containing(const void* addr) const; 310 311 inline ShenandoahHeapRegion* get_region(size_t region_idx) const; 312 313 void heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 314 void parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const; 315 316 inline ShenandoahMmuTracker* mmu_tracker() { return &_mmu_tracker; }; 317 318 // ---------- GC state machinery 319 // 320 // GC state describes the important parts of collector state, that may be 321 // used to make barrier selection decisions in the native and generated code. 322 // Multiple bits can be set at once. 323 // 324 // Important invariant: when GC state is zero, the heap is stable, and no barriers 325 // are required. 326 // 327 public: 328 enum GCStateBitPos { 329 // Heap has forwarded objects: needs LRB barriers. 330 HAS_FORWARDED_BITPOS = 0, 331 332 // Heap is under marking: needs SATB barriers. 333 // For generational mode, it means either young or old marking, or both. 334 MARKING_BITPOS = 1, 335 336 // Heap is under evacuation: needs LRB barriers. (Set together with HAS_FORWARDED) 337 EVACUATION_BITPOS = 2, 338 339 // Heap is under updating: needs no additional barriers. 340 UPDATEREFS_BITPOS = 3, 341 342 // Heap is under weak-reference/roots processing: needs weak-LRB barriers. 343 WEAK_ROOTS_BITPOS = 4, 344 345 // Young regions are under marking, need SATB barriers. 346 YOUNG_MARKING_BITPOS = 5, 347 348 // Old regions are under marking, need SATB barriers. 349 OLD_MARKING_BITPOS = 6 350 }; 351 352 enum GCState { 353 STABLE = 0, 354 HAS_FORWARDED = 1 << HAS_FORWARDED_BITPOS, 355 MARKING = 1 << MARKING_BITPOS, 356 EVACUATION = 1 << EVACUATION_BITPOS, 357 UPDATEREFS = 1 << UPDATEREFS_BITPOS, 358 WEAK_ROOTS = 1 << WEAK_ROOTS_BITPOS, 359 YOUNG_MARKING = 1 << YOUNG_MARKING_BITPOS, 360 OLD_MARKING = 1 << OLD_MARKING_BITPOS 361 }; 362 363 private: 364 bool _gc_state_changed; 365 ShenandoahSharedBitmap _gc_state; 366 ShenandoahSharedFlag _heap_changed; 367 ShenandoahSharedFlag _degenerated_gc_in_progress; 368 ShenandoahSharedFlag _full_gc_in_progress; 369 ShenandoahSharedFlag _full_gc_move_in_progress; 370 ShenandoahSharedFlag _concurrent_strong_root_in_progress; 371 372 size_t _gc_no_progress_count; 373 374 // This updates the singlular, global gc state. This must happen on a safepoint. 375 void set_gc_state(uint mask, bool value); 376 377 public: 378 char gc_state() const; 379 380 // This copies the global gc state into a thread local variable for java threads. 381 // It is primarily intended to support quick access at barriers. 382 void propagate_gc_state_to_java_threads(); 383 384 // This is public to support assertions that the state hasn't been changed off of 385 // a safepoint and that any changes were propagated to java threads after the safepoint. 386 bool has_gc_state_changed() const { return _gc_state_changed; } 387 388 // Returns true if allocations have occurred in new regions or if regions have been 389 // uncommitted since the previous calls. This call will reset the flag to false. 390 bool has_changed() { 391 return _heap_changed.try_unset(); 392 } 393 394 void set_concurrent_young_mark_in_progress(bool in_progress); 395 void set_concurrent_old_mark_in_progress(bool in_progress); 396 void set_evacuation_in_progress(bool in_progress); 397 void set_update_refs_in_progress(bool in_progress); 398 void set_degenerated_gc_in_progress(bool in_progress); 399 void set_full_gc_in_progress(bool in_progress); 400 void set_full_gc_move_in_progress(bool in_progress); 401 void set_has_forwarded_objects(bool cond); 402 void set_concurrent_strong_root_in_progress(bool cond); 403 void set_concurrent_weak_root_in_progress(bool cond); 404 405 inline bool is_stable() const; 406 inline bool is_idle() const; 407 408 inline bool is_concurrent_mark_in_progress() const; 409 inline bool is_concurrent_young_mark_in_progress() const; 410 inline bool is_concurrent_old_mark_in_progress() const; 411 inline bool is_update_refs_in_progress() const; 412 inline bool is_evacuation_in_progress() const; 413 inline bool is_degenerated_gc_in_progress() const; 414 inline bool is_full_gc_in_progress() const; 415 inline bool is_full_gc_move_in_progress() const; 416 inline bool has_forwarded_objects() const; 417 418 inline bool is_stw_gc_in_progress() const; 419 inline bool is_concurrent_strong_root_in_progress() const; 420 inline bool is_concurrent_weak_root_in_progress() const; 421 bool is_prepare_for_old_mark_in_progress() const; 422 423 private: 424 void manage_satb_barrier(bool active); 425 426 enum CancelState { 427 // Normal state. GC has not been cancelled and is open for cancellation. 428 // Worker threads can suspend for safepoint. 429 CANCELLABLE, 430 431 // GC has been cancelled. Worker threads can not suspend for 432 // safepoint but must finish their work as soon as possible. 433 CANCELLED 434 }; 435 436 double _cancel_requested_time; 437 ShenandoahSharedEnumFlag<CancelState> _cancelled_gc; 438 439 // Returns true if cancel request was successfully communicated. 440 // Returns false if some other thread already communicated cancel 441 // request. A true return value does not mean GC has been 442 // cancelled, only that the process of cancelling GC has begun. 443 bool try_cancel_gc(); 444 445 public: 446 inline bool cancelled_gc() const; 447 inline bool check_cancelled_gc_and_yield(bool sts_active = true); 448 449 inline void clear_cancelled_gc(bool clear_oom_handler = true); 450 451 void cancel_concurrent_mark(); 452 void cancel_gc(GCCause::Cause cause); 453 454 public: 455 // These will uncommit empty regions if heap::committed > shrink_until 456 // and there exists at least one region which was made empty before shrink_before. 457 void maybe_uncommit(double shrink_before, size_t shrink_until); 458 void op_uncommit(double shrink_before, size_t shrink_until); 459 460 // Returns true if the soft maximum heap has been changed using management APIs. 461 bool check_soft_max_changed(); 462 463 protected: 464 // This is shared between shConcurrentGC and shDegenerateGC so that degenerated 465 // GC can resume update refs from where the concurrent GC was cancelled. It is 466 // also used in shGenerationalHeap, which uses a different closure for update refs. 467 ShenandoahRegionIterator _update_refs_iterator; 468 469 private: 470 // GC support 471 // Evacuation 472 void evacuate_collection_set(bool concurrent); 473 // Concurrent root processing 474 void prepare_concurrent_roots(); 475 void finish_concurrent_roots(); 476 // Concurrent class unloading support 477 void do_class_unloading(); 478 // Reference updating 479 void prepare_update_heap_references(bool concurrent); 480 virtual void update_heap_references(bool concurrent); 481 // Final update region states 482 void update_heap_region_states(bool concurrent); 483 virtual void final_update_refs_update_region_states(); 484 485 void rendezvous_threads(); 486 void recycle_trash(); 487 public: 488 void rebuild_free_set(bool concurrent); 489 void notify_gc_progress(); 490 void notify_gc_no_progress(); 491 size_t get_gc_no_progress_count() const; 492 493 // 494 // Mark support 495 private: 496 ShenandoahGeneration* _global_generation; 497 498 protected: 499 ShenandoahController* _control_thread; 500 501 ShenandoahYoungGeneration* _young_generation; 502 ShenandoahOldGeneration* _old_generation; 503 504 private: 505 ShenandoahCollectorPolicy* _shenandoah_policy; 506 ShenandoahMode* _gc_mode; 507 ShenandoahFreeSet* _free_set; 508 ShenandoahPacer* _pacer; 509 ShenandoahVerifier* _verifier; 510 511 ShenandoahPhaseTimings* _phase_timings; 512 ShenandoahEvacuationTracker* _evac_tracker; 513 ShenandoahMmuTracker _mmu_tracker; 514 515 public: 516 ShenandoahController* control_thread() { return _control_thread; } 517 518 ShenandoahGeneration* global_generation() const { return _global_generation; } 519 ShenandoahYoungGeneration* young_generation() const { 520 assert(mode()->is_generational(), "Young generation requires generational mode"); 521 return _young_generation; 522 } 523 524 ShenandoahOldGeneration* old_generation() const { 525 assert(mode()->is_generational(), "Old generation requires generational mode"); 526 return _old_generation; 527 } 528 529 ShenandoahGeneration* generation_for(ShenandoahAffiliation affiliation) const; 530 531 ShenandoahCollectorPolicy* shenandoah_policy() const { return _shenandoah_policy; } 532 ShenandoahMode* mode() const { return _gc_mode; } 533 ShenandoahFreeSet* free_set() const { return _free_set; } 534 ShenandoahPacer* pacer() const { return _pacer; } 535 536 ShenandoahPhaseTimings* phase_timings() const { return _phase_timings; } 537 ShenandoahEvacuationTracker* evac_tracker() const { return _evac_tracker; } 538 539 ShenandoahEvacOOMHandler* oom_evac_handler() { return &_oom_evac_handler; } 540 541 void on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation); 542 void on_cycle_end(ShenandoahGeneration* generation); 543 544 ShenandoahVerifier* verifier(); 545 546 // ---------- VM subsystem bindings 547 // 548 private: 549 ShenandoahMonitoringSupport* _monitoring_support; 550 MemoryPool* _memory_pool; 551 GCMemoryManager _stw_memory_manager; 552 GCMemoryManager _cycle_memory_manager; 553 ConcurrentGCTimer* _gc_timer; 554 SoftRefPolicy _soft_ref_policy; 555 556 // For exporting to SA 557 int _log_min_obj_alignment_in_bytes; 558 public: 559 ShenandoahMonitoringSupport* monitoring_support() const { return _monitoring_support; } 560 GCMemoryManager* cycle_memory_manager() { return &_cycle_memory_manager; } 561 GCMemoryManager* stw_memory_manager() { return &_stw_memory_manager; } 562 SoftRefPolicy* soft_ref_policy() override { return &_soft_ref_policy; } 563 564 GrowableArray<GCMemoryManager*> memory_managers() override; 565 GrowableArray<MemoryPool*> memory_pools() override; 566 MemoryUsage memory_usage() override; 567 GCTracer* tracer(); 568 ConcurrentGCTimer* gc_timer() const; 569 570 // ---------- Class Unloading 571 // 572 private: 573 ShenandoahSharedFlag _unload_classes; 574 ShenandoahUnload _unloader; 575 576 public: 577 void set_unload_classes(bool uc); 578 bool unload_classes() const; 579 580 // Perform STW class unloading and weak root cleaning 581 void parallel_cleaning(bool full_gc); 582 583 private: 584 void stw_unload_classes(bool full_gc); 585 void stw_process_weak_roots(bool full_gc); 586 void stw_weak_refs(bool full_gc); 587 588 inline void assert_lock_for_affiliation(ShenandoahAffiliation orig_affiliation, 589 ShenandoahAffiliation new_affiliation); 590 591 // Heap iteration support 592 void scan_roots_for_iteration(ShenandoahScanObjectStack* oop_stack, ObjectIterateScanRootClosure* oops); 593 bool prepare_aux_bitmap_for_iteration(); 594 void reclaim_aux_bitmap_for_iteration(); 595 596 // ---------- Generic interface hooks 597 // Minor things that super-interface expects us to implement to play nice with 598 // the rest of runtime. Some of the things here are not required to be implemented, 599 // and can be stubbed out. 600 // 601 public: 602 bool is_maximal_no_gc() const override shenandoah_not_implemented_return(false); 603 604 inline bool is_in(const void* p) const override; 605 606 inline bool is_in_active_generation(oop obj) const; 607 inline bool is_in_young(const void* p) const; 608 inline bool is_in_old(const void* p) const; 609 inline bool is_old(oop pobj) const; 610 611 inline ShenandoahAffiliation region_affiliation(const ShenandoahHeapRegion* r); 612 inline void set_affiliation(ShenandoahHeapRegion* r, ShenandoahAffiliation new_affiliation); 613 614 inline ShenandoahAffiliation region_affiliation(size_t index); 615 616 bool requires_barriers(stackChunkOop obj) const override; 617 618 MemRegion reserved_region() const { return _reserved; } 619 bool is_in_reserved(const void* addr) const { return _reserved.contains(addr); } 620 621 void collect(GCCause::Cause cause) override; 622 void do_full_collection(bool clear_all_soft_refs) override; 623 624 // Used for parsing heap during error printing 625 HeapWord* block_start(const void* addr) const; 626 bool block_is_obj(const HeapWord* addr) const; 627 bool print_location(outputStream* st, void* addr) const override; 628 629 // Used for native heap walkers: heap dumpers, mostly 630 void object_iterate(ObjectClosure* cl) override; 631 // Parallel heap iteration support 632 ParallelObjectIteratorImpl* parallel_object_iterator(uint workers) override; 633 634 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 635 void keep_alive(oop obj) override; 636 637 // ---------- Safepoint interface hooks 638 // 639 public: 640 void safepoint_synchronize_begin() override; 641 void safepoint_synchronize_end() override; 642 643 // ---------- Code roots handling hooks 644 // 645 public: 646 void register_nmethod(nmethod* nm) override; 647 void unregister_nmethod(nmethod* nm) override; 648 void verify_nmethod(nmethod* nm) override {} 649 650 // ---------- Pinning hooks 651 // 652 public: 653 // Shenandoah supports per-object (per-region) pinning 654 void pin_object(JavaThread* thread, oop obj) override; 655 void unpin_object(JavaThread* thread, oop obj) override; 656 657 void sync_pinned_region_status(); 658 void assert_pinned_region_status() NOT_DEBUG_RETURN; 659 660 // ---------- Concurrent Stack Processing support 661 // 662 public: 663 bool uses_stack_watermark_barrier() const override { return true; } 664 665 // ---------- Allocation support 666 // 667 protected: 668 inline HeapWord* allocate_from_gclab(Thread* thread, size_t size); 669 670 private: 671 HeapWord* allocate_memory_under_lock(ShenandoahAllocRequest& request, bool& in_new_region); 672 HeapWord* allocate_from_gclab_slow(Thread* thread, size_t size); 673 HeapWord* allocate_new_gclab(size_t min_size, size_t word_size, size_t* actual_size); 674 675 public: 676 HeapWord* allocate_memory(ShenandoahAllocRequest& request); 677 HeapWord* mem_allocate(size_t size, bool* what) override; 678 MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 679 size_t size, 680 Metaspace::MetadataType mdtype) override; 681 682 void notify_mutator_alloc_words(size_t words, size_t waste); 683 684 HeapWord* allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) override; 685 size_t tlab_capacity(Thread *thr) const override; 686 size_t unsafe_max_tlab_alloc(Thread *thread) const override; 687 size_t max_tlab_size() const override; 688 size_t tlab_used(Thread* ignored) const override; 689 690 void ensure_parsability(bool retire_labs) override; 691 692 void labs_make_parsable(); 693 void tlabs_retire(bool resize); 694 void gclabs_retire(bool resize); 695 696 // ---------- Marking support 697 // 698 private: 699 ShenandoahMarkingContext* _marking_context; 700 MemRegion _bitmap_region; 701 MemRegion _aux_bitmap_region; 702 MarkBitMap _verification_bit_map; 703 MarkBitMap _aux_bit_map; 704 705 size_t _bitmap_size; 706 size_t _bitmap_regions_per_slice; 707 size_t _bitmap_bytes_per_slice; 708 709 size_t _pretouch_heap_page_size; 710 size_t _pretouch_bitmap_page_size; 711 712 bool _bitmap_region_special; 713 bool _aux_bitmap_region_special; 714 715 ShenandoahLiveData** _liveness_cache; 716 717 public: 718 inline ShenandoahMarkingContext* complete_marking_context() const; 719 inline ShenandoahMarkingContext* marking_context() const; 720 721 template<class T> 722 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl); 723 724 template<class T> 725 inline void marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 726 727 template<class T> 728 inline void marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit); 729 730 // SATB barriers hooks 731 inline bool requires_marking(const void* entry) const; 732 733 // Support for bitmap uncommits 734 bool commit_bitmap_slice(ShenandoahHeapRegion *r); 735 bool uncommit_bitmap_slice(ShenandoahHeapRegion *r); 736 bool is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self = false); 737 738 // Liveness caching support 739 ShenandoahLiveData* get_liveness_cache(uint worker_id); 740 void flush_liveness_cache(uint worker_id); 741 742 size_t pretouch_heap_page_size() { return _pretouch_heap_page_size; } 743 744 // ---------- Evacuation support 745 // 746 private: 747 ShenandoahCollectionSet* _collection_set; 748 ShenandoahEvacOOMHandler _oom_evac_handler; 749 750 oop try_evacuate_object(oop src, Thread* thread, ShenandoahHeapRegion* from_region, ShenandoahAffiliation target_gen); 751 public: 752 753 static address in_cset_fast_test_addr(); 754 755 ShenandoahCollectionSet* collection_set() const { return _collection_set; } 756 757 // Checks if object is in the collection set. 758 inline bool in_collection_set(oop obj) const; 759 760 // Checks if location is in the collection set. Can be interior pointer, not the oop itself. 761 inline bool in_collection_set_loc(void* loc) const; 762 763 // Evacuates or promotes object src. Returns the evacuated object, either evacuated 764 // by this thread, or by some other thread. 765 virtual oop evacuate_object(oop src, Thread* thread); 766 767 // Call before/after evacuation. 768 inline void enter_evacuation(Thread* t); 769 inline void leave_evacuation(Thread* t); 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 log_heap_status(const char *msg) const; 802 803 private: 804 void trash_cset_regions(); 805 806 // ---------- Testing helpers functions 807 // 808 private: 809 ShenandoahSharedFlag _inject_alloc_failure; 810 811 void try_inject_alloc_failure(); 812 bool should_inject_alloc_failure(); 813 }; 814 815 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_HPP --- EOF ---