1 /* 2 * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_GC_G1_G1COLLECTEDHEAP_HPP 26 #define SHARE_GC_G1_G1COLLECTEDHEAP_HPP 27 28 #include "gc/g1/g1BarrierSet.hpp" 29 #include "gc/g1/g1BiasedArray.hpp" 30 #include "gc/g1/g1CardTable.hpp" 31 #include "gc/g1/g1CollectionSet.hpp" 32 #include "gc/g1/g1CollectorState.hpp" 33 #include "gc/g1/g1ConcurrentMark.hpp" 34 #include "gc/g1/g1EdenRegions.hpp" 35 #include "gc/g1/g1EvacFailure.hpp" 36 #include "gc/g1/g1EvacStats.hpp" 37 #include "gc/g1/g1EvacuationInfo.hpp" 38 #include "gc/g1/g1GCPhaseTimes.hpp" 39 #include "gc/g1/g1HeapTransition.hpp" 40 #include "gc/g1/g1HeapVerifier.hpp" 41 #include "gc/g1/g1HRPrinter.hpp" 42 #include "gc/g1/g1HeapRegionAttr.hpp" 43 #include "gc/g1/g1MonitoringSupport.hpp" 44 #include "gc/g1/g1RedirtyCardsQueue.hpp" 45 #include "gc/g1/g1SurvivorRegions.hpp" 46 #include "gc/g1/g1YCTypes.hpp" 47 #include "gc/g1/heapRegionManager.hpp" 48 #include "gc/g1/heapRegionSet.hpp" 49 #include "gc/g1/heterogeneousHeapRegionManager.hpp" 50 #include "gc/shared/barrierSet.hpp" 51 #include "gc/shared/collectedHeap.hpp" 52 #include "gc/shared/gcHeapSummary.hpp" 53 #include "gc/shared/plab.hpp" 54 #include "gc/shared/preservedMarks.hpp" 55 #include "gc/shared/softRefPolicy.hpp" 56 #include "memory/memRegion.hpp" 57 #include "utilities/stack.hpp" 58 59 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot. 60 // It uses the "Garbage First" heap organization and algorithm, which 61 // may combine concurrent marking with parallel, incremental compaction of 62 // heap subsets that will yield large amounts of garbage. 63 64 // Forward declarations 65 class HeapRegion; 66 class GenerationSpec; 67 class G1ParScanThreadState; 68 class G1ParScanThreadStateSet; 69 class G1ParScanThreadState; 70 class MemoryPool; 71 class MemoryManager; 72 class ObjectClosure; 73 class SpaceClosure; 74 class CompactibleSpaceClosure; 75 class Space; 76 class G1CardTableEntryClosure; 77 class G1CollectionSet; 78 class G1Policy; 79 class G1HotCardCache; 80 class G1RemSet; 81 class G1YoungRemSetSamplingThread; 82 class G1ConcurrentMark; 83 class G1ConcurrentMarkThread; 84 class G1ConcurrentRefine; 85 class GenerationCounters; 86 class STWGCTimer; 87 class G1NewTracer; 88 class EvacuationFailedInfo; 89 class nmethod; 90 class WorkGang; 91 class G1Allocator; 92 class G1ArchiveAllocator; 93 class G1FullGCScope; 94 class G1HeapVerifier; 95 class G1HeapSizingPolicy; 96 class G1HeapSummary; 97 class G1EvacSummary; 98 99 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue; 100 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet; 101 102 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() ) 103 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion ) 104 105 // The G1 STW is alive closure. 106 // An instance is embedded into the G1CH and used as the 107 // (optional) _is_alive_non_header closure in the STW 108 // reference processor. It is also extensively used during 109 // reference processing during STW evacuation pauses. 110 class G1STWIsAliveClosure : public BoolObjectClosure { 111 G1CollectedHeap* _g1h; 112 public: 113 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {} 114 bool do_object_b(oop p); 115 }; 116 117 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure { 118 G1CollectedHeap* _g1h; 119 public: 120 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {} 121 bool do_object_b(oop p); 122 }; 123 124 class G1RegionMappingChangedListener : public G1MappingChangedListener { 125 private: 126 void reset_from_card_cache(uint start_idx, size_t num_regions); 127 public: 128 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 129 }; 130 131 class G1CollectedHeap : public CollectedHeap { 132 friend class G1FreeCollectionSetTask; 133 friend class VM_CollectForMetadataAllocation; 134 friend class VM_G1CollectForAllocation; 135 friend class VM_G1CollectFull; 136 friend class VMStructs; 137 friend class MutatorAllocRegion; 138 friend class G1FullCollector; 139 friend class G1GCAllocRegion; 140 friend class G1HeapVerifier; 141 142 // Closures used in implementation. 143 friend class G1ParScanThreadState; 144 friend class G1ParScanThreadStateSet; 145 friend class G1EvacuateRegionsTask; 146 friend class G1PLABAllocator; 147 148 // Other related classes. 149 friend class HeapRegionClaimer; 150 151 // Testing classes. 152 friend class G1CheckRegionAttrTableClosure; 153 154 private: 155 G1YoungRemSetSamplingThread* _young_gen_sampling_thread; 156 157 WorkGang* _workers; 158 G1CardTable* _card_table; 159 160 SoftRefPolicy _soft_ref_policy; 161 162 static size_t _humongous_object_threshold_in_words; 163 164 // These sets keep track of old, archive and humongous regions respectively. 165 HeapRegionSet _old_set; 166 HeapRegionSet _archive_set; 167 HeapRegionSet _humongous_set; 168 169 void eagerly_reclaim_humongous_regions(); 170 // Start a new incremental collection set for the next pause. 171 void start_new_collection_set(); 172 173 // The block offset table for the G1 heap. 174 G1BlockOffsetTable* _bot; 175 176 // Tears down the region sets / lists so that they are empty and the 177 // regions on the heap do not belong to a region set / list. The 178 // only exception is the humongous set which we leave unaltered. If 179 // free_list_only is true, it will only tear down the master free 180 // list. It is called before a Full GC (free_list_only == false) or 181 // before heap shrinking (free_list_only == true). 182 void tear_down_region_sets(bool free_list_only); 183 184 // Rebuilds the region sets / lists so that they are repopulated to 185 // reflect the contents of the heap. The only exception is the 186 // humongous set which was not torn down in the first place. If 187 // free_list_only is true, it will only rebuild the master free 188 // list. It is called after a Full GC (free_list_only == false) or 189 // after heap shrinking (free_list_only == true). 190 void rebuild_region_sets(bool free_list_only); 191 192 // Callback for region mapping changed events. 193 G1RegionMappingChangedListener _listener; 194 195 // The sequence of all heap regions in the heap. 196 HeapRegionManager* _hrm; 197 198 // Manages all allocations with regions except humongous object allocations. 199 G1Allocator* _allocator; 200 201 // Manages all heap verification. 202 G1HeapVerifier* _verifier; 203 204 // Outside of GC pauses, the number of bytes used in all regions other 205 // than the current allocation region(s). 206 volatile size_t _summary_bytes_used; 207 208 void increase_used(size_t bytes); 209 void decrease_used(size_t bytes); 210 211 void set_used(size_t bytes); 212 213 // Class that handles archive allocation ranges. 214 G1ArchiveAllocator* _archive_allocator; 215 216 // GC allocation statistics policy for survivors. 217 G1EvacStats _survivor_evac_stats; 218 219 // GC allocation statistics policy for tenured objects. 220 G1EvacStats _old_evac_stats; 221 222 // It specifies whether we should attempt to expand the heap after a 223 // region allocation failure. If heap expansion fails we set this to 224 // false so that we don't re-attempt the heap expansion (it's likely 225 // that subsequent expansion attempts will also fail if one fails). 226 // Currently, it is only consulted during GC and it's reset at the 227 // start of each GC. 228 bool _expand_heap_after_alloc_failure; 229 230 // Helper for monitoring and management support. 231 G1MonitoringSupport* _g1mm; 232 233 // Records whether the region at the given index is (still) a 234 // candidate for eager reclaim. Only valid for humongous start 235 // regions; other regions have unspecified values. Humongous start 236 // regions are initialized at start of collection pause, with 237 // candidates removed from the set as they are found reachable from 238 // roots or the young generation. 239 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> { 240 protected: 241 bool default_value() const { return false; } 242 public: 243 void clear() { G1BiasedMappedArray<bool>::clear(); } 244 void set_candidate(uint region, bool value) { 245 set_by_index(region, value); 246 } 247 bool is_candidate(uint region) { 248 return get_by_index(region); 249 } 250 }; 251 252 HumongousReclaimCandidates _humongous_reclaim_candidates; 253 // Stores whether during humongous object registration we found candidate regions. 254 // If not, we can skip a few steps. 255 bool _has_humongous_reclaim_candidates; 256 257 G1HRPrinter _hr_printer; 258 259 // It decides whether an explicit GC should start a concurrent cycle 260 // instead of doing a STW GC. Currently, a concurrent cycle is 261 // explicitly started if: 262 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or 263 // (b) cause == _g1_humongous_allocation 264 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent. 265 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent. 266 // (e) cause == _wb_conc_mark 267 bool should_do_concurrent_full_gc(GCCause::Cause cause); 268 269 // Return true if should upgrade to full gc after an incremental one. 270 bool should_upgrade_to_full_gc(GCCause::Cause cause); 271 272 // indicates whether we are in young or mixed GC mode 273 G1CollectorState _collector_state; 274 275 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 276 // concurrent cycles) we have started. 277 volatile uint _old_marking_cycles_started; 278 279 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 280 // concurrent cycles) we have completed. 281 volatile uint _old_marking_cycles_completed; 282 283 // This is a non-product method that is helpful for testing. It is 284 // called at the end of a GC and artificially expands the heap by 285 // allocating a number of dead regions. This way we can induce very 286 // frequent marking cycles and stress the cleanup / concurrent 287 // cleanup code more (as all the regions that will be allocated by 288 // this method will be found dead by the marking cycle). 289 void allocate_dummy_regions() PRODUCT_RETURN; 290 291 // If the HR printer is active, dump the state of the regions in the 292 // heap after a compaction. 293 void print_hrm_post_compaction(); 294 295 // Create a memory mapper for auxiliary data structures of the given size and 296 // translation factor. 297 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description, 298 size_t size, 299 size_t translation_factor); 300 301 void trace_heap(GCWhen::Type when, const GCTracer* tracer); 302 303 // These are macros so that, if the assert fires, we get the correct 304 // line number, file, etc. 305 306 #define heap_locking_asserts_params(_extra_message_) \ 307 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 308 (_extra_message_), \ 309 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 310 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 311 BOOL_TO_STR(Thread::current()->is_VM_thread()) 312 313 #define assert_heap_locked() \ 314 do { \ 315 assert(Heap_lock->owned_by_self(), \ 316 heap_locking_asserts_params("should be holding the Heap_lock")); \ 317 } while (0) 318 319 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 320 do { \ 321 assert(Heap_lock->owned_by_self() || \ 322 (SafepointSynchronize::is_at_safepoint() && \ 323 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 324 heap_locking_asserts_params("should be holding the Heap_lock or " \ 325 "should be at a safepoint")); \ 326 } while (0) 327 328 #define assert_heap_locked_and_not_at_safepoint() \ 329 do { \ 330 assert(Heap_lock->owned_by_self() && \ 331 !SafepointSynchronize::is_at_safepoint(), \ 332 heap_locking_asserts_params("should be holding the Heap_lock and " \ 333 "should not be at a safepoint")); \ 334 } while (0) 335 336 #define assert_heap_not_locked() \ 337 do { \ 338 assert(!Heap_lock->owned_by_self(), \ 339 heap_locking_asserts_params("should not be holding the Heap_lock")); \ 340 } while (0) 341 342 #define assert_heap_not_locked_and_not_at_safepoint() \ 343 do { \ 344 assert(!Heap_lock->owned_by_self() && \ 345 !SafepointSynchronize::is_at_safepoint(), \ 346 heap_locking_asserts_params("should not be holding the Heap_lock and " \ 347 "should not be at a safepoint")); \ 348 } while (0) 349 350 #define assert_at_safepoint_on_vm_thread() \ 351 do { \ 352 assert_at_safepoint(); \ 353 assert(Thread::current_or_null() != NULL, "no current thread"); \ 354 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \ 355 } while (0) 356 357 #ifdef ASSERT 358 #define assert_used_and_recalculate_used_equal(g1h) \ 359 do { \ 360 size_t cur_used_bytes = g1h->used(); \ 361 size_t recal_used_bytes = g1h->recalculate_used(); \ 362 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \ 363 " same as recalculated used(" SIZE_FORMAT ").", \ 364 cur_used_bytes, recal_used_bytes); \ 365 } while (0) 366 #else 367 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0) 368 #endif 369 370 const char* young_gc_name() const; 371 372 // The young region list. 373 G1EdenRegions _eden; 374 G1SurvivorRegions _survivor; 375 376 STWGCTimer* _gc_timer_stw; 377 378 G1NewTracer* _gc_tracer_stw; 379 380 // The current policy object for the collector. 381 G1Policy* _policy; 382 G1HeapSizingPolicy* _heap_sizing_policy; 383 384 G1CollectionSet _collection_set; 385 386 // Try to allocate a single non-humongous HeapRegion sufficient for 387 // an allocation of the given word_size. If do_expand is true, 388 // attempt to expand the heap if necessary to satisfy the allocation 389 // request. 'type' takes the type of region to be allocated. (Use constants 390 // Old, Eden, Humongous, Survivor defined in HeapRegionType.) 391 HeapRegion* new_region(size_t word_size, HeapRegionType type, bool do_expand); 392 393 // Initialize a contiguous set of free regions of length num_regions 394 // and starting at index first so that they appear as a single 395 // humongous region. 396 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 397 uint num_regions, 398 size_t word_size); 399 400 // Attempt to allocate a humongous object of the given size. Return 401 // NULL if unsuccessful. 402 HeapWord* humongous_obj_allocate(size_t word_size); 403 404 // The following two methods, allocate_new_tlab() and 405 // mem_allocate(), are the two main entry points from the runtime 406 // into the G1's allocation routines. They have the following 407 // assumptions: 408 // 409 // * They should both be called outside safepoints. 410 // 411 // * They should both be called without holding the Heap_lock. 412 // 413 // * All allocation requests for new TLABs should go to 414 // allocate_new_tlab(). 415 // 416 // * All non-TLAB allocation requests should go to mem_allocate(). 417 // 418 // * If either call cannot satisfy the allocation request using the 419 // current allocating region, they will try to get a new one. If 420 // this fails, they will attempt to do an evacuation pause and 421 // retry the allocation. 422 // 423 // * If all allocation attempts fail, even after trying to schedule 424 // an evacuation pause, allocate_new_tlab() will return NULL, 425 // whereas mem_allocate() will attempt a heap expansion and/or 426 // schedule a Full GC. 427 // 428 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 429 // should never be called with word_size being humongous. All 430 // humongous allocation requests should go to mem_allocate() which 431 // will satisfy them with a special path. 432 433 virtual HeapWord* allocate_new_tlab(size_t min_size, 434 size_t requested_size, 435 size_t* actual_size); 436 437 virtual HeapWord* mem_allocate(size_t word_size, 438 bool* gc_overhead_limit_was_exceeded); 439 440 // First-level mutator allocation attempt: try to allocate out of 441 // the mutator alloc region without taking the Heap_lock. This 442 // should only be used for non-humongous allocations. 443 inline HeapWord* attempt_allocation(size_t min_word_size, 444 size_t desired_word_size, 445 size_t* actual_word_size); 446 447 // Second-level mutator allocation attempt: take the Heap_lock and 448 // retry the allocation attempt, potentially scheduling a GC 449 // pause. This should only be used for non-humongous allocations. 450 HeapWord* attempt_allocation_slow(size_t word_size); 451 452 // Takes the Heap_lock and attempts a humongous allocation. It can 453 // potentially schedule a GC pause. 454 HeapWord* attempt_allocation_humongous(size_t word_size); 455 456 // Allocation attempt that should be called during safepoints (e.g., 457 // at the end of a successful GC). expect_null_mutator_alloc_region 458 // specifies whether the mutator alloc region is expected to be NULL 459 // or not. 460 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 461 bool expect_null_mutator_alloc_region); 462 463 // These methods are the "callbacks" from the G1AllocRegion class. 464 465 // For mutator alloc regions. 466 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force); 467 void retire_mutator_alloc_region(HeapRegion* alloc_region, 468 size_t allocated_bytes); 469 470 // For GC alloc regions. 471 bool has_more_regions(G1HeapRegionAttr dest); 472 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest); 473 void retire_gc_alloc_region(HeapRegion* alloc_region, 474 size_t allocated_bytes, G1HeapRegionAttr dest); 475 476 // - if explicit_gc is true, the GC is for a System.gc() etc, 477 // otherwise it's for a failed allocation. 478 // - if clear_all_soft_refs is true, all soft references should be 479 // cleared during the GC. 480 // - it returns false if it is unable to do the collection due to the 481 // GC locker being active, true otherwise. 482 bool do_full_collection(bool explicit_gc, 483 bool clear_all_soft_refs); 484 485 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread. 486 virtual void do_full_collection(bool clear_all_soft_refs); 487 488 // Callback from VM_G1CollectForAllocation operation. 489 // This function does everything necessary/possible to satisfy a 490 // failed allocation request (including collection, expansion, etc.) 491 HeapWord* satisfy_failed_allocation(size_t word_size, 492 bool* succeeded); 493 // Internal helpers used during full GC to split it up to 494 // increase readability. 495 void abort_concurrent_cycle(); 496 void verify_before_full_collection(bool explicit_gc); 497 void prepare_heap_for_full_collection(); 498 void prepare_heap_for_mutators(); 499 void abort_refinement(); 500 void verify_after_full_collection(); 501 void print_heap_after_full_collection(G1HeapTransition* heap_transition); 502 503 // Helper method for satisfy_failed_allocation() 504 HeapWord* satisfy_failed_allocation_helper(size_t word_size, 505 bool do_gc, 506 bool clear_all_soft_refs, 507 bool expect_null_mutator_alloc_region, 508 bool* gc_succeeded); 509 510 // Attempting to expand the heap sufficiently 511 // to support an allocation of the given "word_size". If 512 // successful, perform the allocation and return the address of the 513 // allocated block, or else "NULL". 514 HeapWord* expand_and_allocate(size_t word_size); 515 516 // Process any reference objects discovered. 517 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states); 518 519 // If during an initial mark pause we may install a pending list head which is not 520 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking 521 // to discover. 522 void make_pending_list_reachable(); 523 524 // Merges the information gathered on a per-thread basis for all worker threads 525 // during GC into global variables. 526 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states); 527 public: 528 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; } 529 530 WorkGang* workers() const { return _workers; } 531 532 // Runs the given AbstractGangTask with the current active workers, returning the 533 // total time taken. 534 Tickspan run_task(AbstractGangTask* task); 535 536 G1Allocator* allocator() { 537 return _allocator; 538 } 539 540 G1HeapVerifier* verifier() { 541 return _verifier; 542 } 543 544 G1MonitoringSupport* g1mm() { 545 assert(_g1mm != NULL, "should have been initialized"); 546 return _g1mm; 547 } 548 549 void resize_heap_if_necessary(); 550 551 // Expand the garbage-first heap by at least the given size (in bytes!). 552 // Returns true if the heap was expanded by the requested amount; 553 // false otherwise. 554 // (Rounds up to a HeapRegion boundary.) 555 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL); 556 557 // Returns the PLAB statistics for a given destination. 558 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest); 559 560 // Determines PLAB size for a given destination. 561 inline size_t desired_plab_sz(G1HeapRegionAttr dest); 562 563 // Do anything common to GC's. 564 void gc_prologue(bool full); 565 void gc_epilogue(bool full); 566 567 // Does the given region fulfill remembered set based eager reclaim candidate requirements? 568 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const; 569 570 // Modify the reclaim candidate set and test for presence. 571 // These are only valid for starts_humongous regions. 572 inline void set_humongous_reclaim_candidate(uint region, bool value); 573 inline bool is_humongous_reclaim_candidate(uint region); 574 575 // Remove from the reclaim candidate set. Also remove from the 576 // collection set so that later encounters avoid the slow path. 577 inline void set_humongous_is_live(oop obj); 578 579 // Register the given region to be part of the collection set. 580 inline void register_humongous_region_with_region_attr(uint index); 581 // Update region attributes table with information about all regions. 582 void register_regions_with_region_attr(); 583 // We register a region with the fast "in collection set" test. We 584 // simply set to true the array slot corresponding to this region. 585 void register_young_region_with_region_attr(HeapRegion* r) { 586 _region_attr.set_in_young(r->hrm_index()); 587 } 588 inline void register_region_with_region_attr(HeapRegion* r); 589 inline void register_old_region_with_region_attr(HeapRegion* r); 590 inline void register_optional_region_with_region_attr(HeapRegion* r); 591 592 void clear_region_attr(const HeapRegion* hr) { 593 _region_attr.clear(hr); 594 } 595 596 void clear_region_attr() { 597 _region_attr.clear(); 598 } 599 600 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking 601 // for all regions. 602 void verify_region_attr_remset_update() PRODUCT_RETURN; 603 604 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause); 605 606 // This is called at the start of either a concurrent cycle or a Full 607 // GC to update the number of old marking cycles started. 608 void increment_old_marking_cycles_started(); 609 610 // This is called at the end of either a concurrent cycle or a Full 611 // GC to update the number of old marking cycles completed. Those two 612 // can happen in a nested fashion, i.e., we start a concurrent 613 // cycle, a Full GC happens half-way through it which ends first, 614 // and then the cycle notices that a Full GC happened and ends 615 // too. The concurrent parameter is a boolean to help us do a bit 616 // tighter consistency checking in the method. If concurrent is 617 // false, the caller is the inner caller in the nesting (i.e., the 618 // Full GC). If concurrent is true, the caller is the outer caller 619 // in this nesting (i.e., the concurrent cycle). Further nesting is 620 // not currently supported. The end of this call also notifies 621 // the FullGCCount_lock in case a Java thread is waiting for a full 622 // GC to happen (e.g., it called System.gc() with 623 // +ExplicitGCInvokesConcurrent). 624 void increment_old_marking_cycles_completed(bool concurrent); 625 626 uint old_marking_cycles_completed() { 627 return _old_marking_cycles_completed; 628 } 629 630 G1HRPrinter* hr_printer() { return &_hr_printer; } 631 632 // Allocates a new heap region instance. 633 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr); 634 635 // Allocate the highest free region in the reserved heap. This will commit 636 // regions as necessary. 637 HeapRegion* alloc_highest_free_region(); 638 639 // Frees a non-humongous region by initializing its contents and 640 // adding it to the free list that's passed as a parameter (this is 641 // usually a local list which will be appended to the master free 642 // list later). The used bytes of freed regions are accumulated in 643 // pre_used. If skip_remset is true, the region's RSet will not be freed 644 // up. If skip_hot_card_cache is true, the region's hot card cache will not 645 // be freed up. The assumption is that this will be done later. 646 // The locked parameter indicates if the caller has already taken 647 // care of proper synchronization. This may allow some optimizations. 648 void free_region(HeapRegion* hr, 649 FreeRegionList* free_list, 650 bool skip_remset, 651 bool skip_hot_card_cache = false, 652 bool locked = false); 653 654 // It dirties the cards that cover the block so that the post 655 // write barrier never queues anything when updating objects on this 656 // block. It is assumed (and in fact we assert) that the block 657 // belongs to a young region. 658 inline void dirty_young_block(HeapWord* start, size_t word_size); 659 660 // Frees a humongous region by collapsing it into individual regions 661 // and calling free_region() for each of them. The freed regions 662 // will be added to the free list that's passed as a parameter (this 663 // is usually a local list which will be appended to the master free 664 // list later). 665 // The method assumes that only a single thread is ever calling 666 // this for a particular region at once. 667 void free_humongous_region(HeapRegion* hr, 668 FreeRegionList* free_list); 669 670 // Facility for allocating in 'archive' regions in high heap memory and 671 // recording the allocated ranges. These should all be called from the 672 // VM thread at safepoints, without the heap lock held. They can be used 673 // to create and archive a set of heap regions which can be mapped at the 674 // same fixed addresses in a subsequent JVM invocation. 675 void begin_archive_alloc_range(bool open = false); 676 677 // Check if the requested size would be too large for an archive allocation. 678 bool is_archive_alloc_too_large(size_t word_size); 679 680 // Allocate memory of the requested size from the archive region. This will 681 // return NULL if the size is too large or if no memory is available. It 682 // does not trigger a garbage collection. 683 HeapWord* archive_mem_allocate(size_t word_size); 684 685 // Optionally aligns the end address and returns the allocated ranges in 686 // an array of MemRegions in order of ascending addresses. 687 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges, 688 size_t end_alignment_in_bytes = 0); 689 690 // Facility for allocating a fixed range within the heap and marking 691 // the containing regions as 'archive'. For use at JVM init time, when the 692 // caller may mmap archived heap data at the specified range(s). 693 // Verify that the MemRegions specified in the argument array are within the 694 // reserved heap. 695 bool check_archive_addresses(MemRegion* range, size_t count); 696 697 // Commit the appropriate G1 regions containing the specified MemRegions 698 // and mark them as 'archive' regions. The regions in the array must be 699 // non-overlapping and in order of ascending address. 700 bool alloc_archive_regions(MemRegion* range, size_t count, bool open); 701 702 // Insert any required filler objects in the G1 regions around the specified 703 // ranges to make the regions parseable. This must be called after 704 // alloc_archive_regions, and after class loading has occurred. 705 void fill_archive_regions(MemRegion* range, size_t count); 706 707 // For each of the specified MemRegions, uncommit the containing G1 regions 708 // which had been allocated by alloc_archive_regions. This should be called 709 // rather than fill_archive_regions at JVM init time if the archive file 710 // mapping failed, with the same non-overlapping and sorted MemRegion array. 711 void dealloc_archive_regions(MemRegion* range, size_t count, bool is_open); 712 713 oop materialize_archived_object(oop obj); 714 715 private: 716 717 // Shrink the garbage-first heap by at most the given size (in bytes!). 718 // (Rounds down to a HeapRegion boundary.) 719 void shrink(size_t expand_bytes); 720 void shrink_helper(size_t expand_bytes); 721 722 #if TASKQUEUE_STATS 723 static void print_taskqueue_stats_hdr(outputStream* const st); 724 void print_taskqueue_stats() const; 725 void reset_taskqueue_stats(); 726 #endif // TASKQUEUE_STATS 727 728 // Schedule the VM operation that will do an evacuation pause to 729 // satisfy an allocation request of word_size. *succeeded will 730 // return whether the VM operation was successful (it did do an 731 // evacuation pause) or not (another thread beat us to it or the GC 732 // locker was active). Given that we should not be holding the 733 // Heap_lock when we enter this method, we will pass the 734 // gc_count_before (i.e., total_collections()) as a parameter since 735 // it has to be read while holding the Heap_lock. Currently, both 736 // methods that call do_collection_pause() release the Heap_lock 737 // before the call, so it's easy to read gc_count_before just before. 738 HeapWord* do_collection_pause(size_t word_size, 739 uint gc_count_before, 740 bool* succeeded, 741 GCCause::Cause gc_cause); 742 743 void wait_for_root_region_scanning(); 744 745 // The guts of the incremental collection pause, executed by the vm 746 // thread. It returns false if it is unable to do the collection due 747 // to the GC locker being active, true otherwise 748 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 749 750 G1HeapVerifier::G1VerifyType young_collection_verify_type() const; 751 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type); 752 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type); 753 754 void calculate_collection_set(G1EvacuationInfo& evacuation_info, double target_pause_time_ms); 755 756 // Actually do the work of evacuating the parts of the collection set. 757 void evacuate_initial_collection_set(G1ParScanThreadStateSet* per_thread_states); 758 void evacuate_optional_collection_set(G1ParScanThreadStateSet* per_thread_states); 759 private: 760 // Evacuate the next set of optional regions. 761 void evacuate_next_optional_regions(G1ParScanThreadStateSet* per_thread_states); 762 763 public: 764 void pre_evacuate_collection_set(G1EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss); 765 void post_evacuate_collection_set(G1EvacuationInfo& evacuation_info, 766 G1RedirtyCardsQueueSet* rdcqs, 767 G1ParScanThreadStateSet* pss); 768 769 void expand_heap_after_young_collection(); 770 // Update object copying statistics. 771 void record_obj_copy_mem_stats(); 772 773 // The hot card cache for remembered set insertion optimization. 774 G1HotCardCache* _hot_card_cache; 775 776 // The g1 remembered set of the heap. 777 G1RemSet* _rem_set; 778 779 // After a collection pause, convert the regions in the collection set into free 780 // regions. 781 void free_collection_set(G1CollectionSet* collection_set, G1EvacuationInfo& evacuation_info, const size_t* surviving_young_words); 782 783 // Abandon the current collection set without recording policy 784 // statistics or updating free lists. 785 void abandon_collection_set(G1CollectionSet* collection_set); 786 787 // The concurrent marker (and the thread it runs in.) 788 G1ConcurrentMark* _cm; 789 G1ConcurrentMarkThread* _cm_thread; 790 791 // The concurrent refiner. 792 G1ConcurrentRefine* _cr; 793 794 // The parallel task queues 795 RefToScanQueueSet *_task_queues; 796 797 // True iff a evacuation has failed in the current collection. 798 bool _evacuation_failed; 799 800 EvacuationFailedInfo* _evacuation_failed_info_array; 801 802 // Failed evacuations cause some logical from-space objects to have 803 // forwarding pointers to themselves. Reset them. 804 void remove_self_forwarding_pointers(G1RedirtyCardsQueueSet* rdcqs); 805 806 // Restore the objects in the regions in the collection set after an 807 // evacuation failure. 808 void restore_after_evac_failure(G1RedirtyCardsQueueSet* rdcqs); 809 810 PreservedMarksSet _preserved_marks_set; 811 812 // Preserve the mark of "obj", if necessary, in preparation for its mark 813 // word being overwritten with a self-forwarding-pointer. 814 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markWord m); 815 816 #ifndef PRODUCT 817 // Support for forcing evacuation failures. Analogous to 818 // PromotionFailureALot for the other collectors. 819 820 // Records whether G1EvacuationFailureALot should be in effect 821 // for the current GC 822 bool _evacuation_failure_alot_for_current_gc; 823 824 // Used to record the GC number for interval checking when 825 // determining whether G1EvaucationFailureALot is in effect 826 // for the current GC. 827 size_t _evacuation_failure_alot_gc_number; 828 829 // Count of the number of evacuations between failures. 830 volatile size_t _evacuation_failure_alot_count; 831 832 // Set whether G1EvacuationFailureALot should be in effect 833 // for the current GC (based upon the type of GC and which 834 // command line flags are set); 835 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc, 836 bool during_initial_mark, 837 bool mark_or_rebuild_in_progress); 838 839 inline void set_evacuation_failure_alot_for_current_gc(); 840 841 // Return true if it's time to cause an evacuation failure. 842 inline bool evacuation_should_fail(); 843 844 // Reset the G1EvacuationFailureALot counters. Should be called at 845 // the end of an evacuation pause in which an evacuation failure occurred. 846 inline void reset_evacuation_should_fail(); 847 #endif // !PRODUCT 848 849 // ("Weak") Reference processing support. 850 // 851 // G1 has 2 instances of the reference processor class. One 852 // (_ref_processor_cm) handles reference object discovery 853 // and subsequent processing during concurrent marking cycles. 854 // 855 // The other (_ref_processor_stw) handles reference object 856 // discovery and processing during full GCs and incremental 857 // evacuation pauses. 858 // 859 // During an incremental pause, reference discovery will be 860 // temporarily disabled for _ref_processor_cm and will be 861 // enabled for _ref_processor_stw. At the end of the evacuation 862 // pause references discovered by _ref_processor_stw will be 863 // processed and discovery will be disabled. The previous 864 // setting for reference object discovery for _ref_processor_cm 865 // will be re-instated. 866 // 867 // At the start of marking: 868 // * Discovery by the CM ref processor is verified to be inactive 869 // and it's discovered lists are empty. 870 // * Discovery by the CM ref processor is then enabled. 871 // 872 // At the end of marking: 873 // * Any references on the CM ref processor's discovered 874 // lists are processed (possibly MT). 875 // 876 // At the start of full GC we: 877 // * Disable discovery by the CM ref processor and 878 // empty CM ref processor's discovered lists 879 // (without processing any entries). 880 // * Verify that the STW ref processor is inactive and it's 881 // discovered lists are empty. 882 // * Temporarily set STW ref processor discovery as single threaded. 883 // * Temporarily clear the STW ref processor's _is_alive_non_header 884 // field. 885 // * Finally enable discovery by the STW ref processor. 886 // 887 // The STW ref processor is used to record any discovered 888 // references during the full GC. 889 // 890 // At the end of a full GC we: 891 // * Enqueue any reference objects discovered by the STW ref processor 892 // that have non-live referents. This has the side-effect of 893 // making the STW ref processor inactive by disabling discovery. 894 // * Verify that the CM ref processor is still inactive 895 // and no references have been placed on it's discovered 896 // lists (also checked as a precondition during initial marking). 897 898 // The (stw) reference processor... 899 ReferenceProcessor* _ref_processor_stw; 900 901 // During reference object discovery, the _is_alive_non_header 902 // closure (if non-null) is applied to the referent object to 903 // determine whether the referent is live. If so then the 904 // reference object does not need to be 'discovered' and can 905 // be treated as a regular oop. This has the benefit of reducing 906 // the number of 'discovered' reference objects that need to 907 // be processed. 908 // 909 // Instance of the is_alive closure for embedding into the 910 // STW reference processor as the _is_alive_non_header field. 911 // Supplying a value for the _is_alive_non_header field is 912 // optional but doing so prevents unnecessary additions to 913 // the discovered lists during reference discovery. 914 G1STWIsAliveClosure _is_alive_closure_stw; 915 916 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw; 917 918 // The (concurrent marking) reference processor... 919 ReferenceProcessor* _ref_processor_cm; 920 921 // Instance of the concurrent mark is_alive closure for embedding 922 // into the Concurrent Marking reference processor as the 923 // _is_alive_non_header field. Supplying a value for the 924 // _is_alive_non_header field is optional but doing so prevents 925 // unnecessary additions to the discovered lists during reference 926 // discovery. 927 G1CMIsAliveClosure _is_alive_closure_cm; 928 929 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm; 930 public: 931 932 RefToScanQueue *task_queue(uint i) const; 933 934 uint num_task_queues() const; 935 936 // Create a G1CollectedHeap. 937 // Must call the initialize method afterwards. 938 // May not return if something goes wrong. 939 G1CollectedHeap(); 940 941 private: 942 jint initialize_concurrent_refinement(); 943 jint initialize_young_gen_sampling_thread(); 944 public: 945 // Initialize the G1CollectedHeap to have the initial and 946 // maximum sizes and remembered and barrier sets 947 // specified by the policy object. 948 jint initialize(); 949 950 virtual void stop(); 951 virtual void safepoint_synchronize_begin(); 952 virtual void safepoint_synchronize_end(); 953 954 // Does operations required after initialization has been done. 955 void post_initialize(); 956 957 // Initialize weak reference processing. 958 void ref_processing_init(); 959 960 virtual Name kind() const { 961 return CollectedHeap::G1; 962 } 963 964 virtual const char* name() const { 965 return "G1"; 966 } 967 968 const G1CollectorState* collector_state() const { return &_collector_state; } 969 G1CollectorState* collector_state() { return &_collector_state; } 970 971 // The current policy object for the collector. 972 G1Policy* policy() const { return _policy; } 973 // The remembered set. 974 G1RemSet* rem_set() const { return _rem_set; } 975 976 inline G1GCPhaseTimes* phase_times() const; 977 978 HeapRegionManager* hrm() const { return _hrm; } 979 980 const G1CollectionSet* collection_set() const { return &_collection_set; } 981 G1CollectionSet* collection_set() { return &_collection_set; } 982 983 virtual SoftRefPolicy* soft_ref_policy(); 984 985 virtual void initialize_serviceability(); 986 virtual MemoryUsage memory_usage(); 987 virtual GrowableArray<GCMemoryManager*> memory_managers(); 988 virtual GrowableArray<MemoryPool*> memory_pools(); 989 990 // Try to minimize the remembered set. 991 void scrub_rem_set(); 992 993 // Apply the given closure on all cards in the Hot Card Cache, emptying it. 994 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id); 995 996 // The shared block offset table array. 997 G1BlockOffsetTable* bot() const { return _bot; } 998 999 // Reference Processing accessors 1000 1001 // The STW reference processor.... 1002 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 1003 1004 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; } 1005 1006 // The Concurrent Marking reference processor... 1007 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 1008 1009 size_t unused_committed_regions_in_bytes() const; 1010 1011 virtual size_t capacity() const; 1012 virtual size_t used() const; 1013 // This should be called when we're not holding the heap lock. The 1014 // result might be a bit inaccurate. 1015 size_t used_unlocked() const; 1016 size_t recalculate_used() const; 1017 1018 // These virtual functions do the actual allocation. 1019 // Some heaps may offer a contiguous region for shared non-blocking 1020 // allocation, via inlined code (by exporting the address of the top and 1021 // end fields defining the extent of the contiguous allocation region.) 1022 // But G1CollectedHeap doesn't yet support this. 1023 1024 virtual bool is_maximal_no_gc() const { 1025 return _hrm->available() == 0; 1026 } 1027 1028 // Returns whether there are any regions left in the heap for allocation. 1029 bool has_regions_left_for_allocation() const { 1030 return !is_maximal_no_gc() || num_free_regions() != 0; 1031 } 1032 1033 // The current number of regions in the heap. 1034 uint num_regions() const { return _hrm->length(); } 1035 1036 // The max number of regions in the heap. 1037 uint max_regions() const { return _hrm->max_length(); } 1038 1039 // Max number of regions that can be comitted. 1040 uint max_expandable_regions() const { return _hrm->max_expandable_length(); } 1041 1042 // The number of regions that are completely free. 1043 uint num_free_regions() const { return _hrm->num_free_regions(); } 1044 1045 // The number of regions that can be allocated into. 1046 uint num_free_or_available_regions() const { return num_free_regions() + _hrm->available(); } 1047 1048 MemoryUsage get_auxiliary_data_memory_usage() const { 1049 return _hrm->get_auxiliary_data_memory_usage(); 1050 } 1051 1052 // The number of regions that are not completely free. 1053 uint num_used_regions() const { return num_regions() - num_free_regions(); } 1054 1055 #ifdef ASSERT 1056 bool is_on_master_free_list(HeapRegion* hr) { 1057 return _hrm->is_free(hr); 1058 } 1059 #endif // ASSERT 1060 1061 inline void old_set_add(HeapRegion* hr); 1062 inline void old_set_remove(HeapRegion* hr); 1063 1064 inline void archive_set_add(HeapRegion* hr); 1065 1066 size_t non_young_capacity_bytes() { 1067 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes; 1068 } 1069 1070 // Determine whether the given region is one that we are using as an 1071 // old GC alloc region. 1072 bool is_old_gc_alloc_region(HeapRegion* hr); 1073 1074 // Perform a collection of the heap; intended for use in implementing 1075 // "System.gc". This probably implies as full a collection as the 1076 // "CollectedHeap" supports. 1077 virtual void collect(GCCause::Cause cause); 1078 1079 // Perform a collection of the heap with the given cause; if the VM operation 1080 // fails to execute for any reason, retry only if retry_on_gc_failure is set. 1081 // Returns whether this collection actually executed. 1082 bool try_collect(GCCause::Cause cause, bool retry_on_gc_failure); 1083 1084 // True iff an evacuation has failed in the most-recent collection. 1085 bool evacuation_failed() { return _evacuation_failed; } 1086 1087 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed); 1088 void prepend_to_freelist(FreeRegionList* list); 1089 void decrement_summary_bytes(size_t bytes); 1090 1091 virtual bool is_in(const void* p) const; 1092 #ifdef ASSERT 1093 // Returns whether p is in one of the available areas of the heap. Slow but 1094 // extensive version. 1095 bool is_in_exact(const void* p) const; 1096 #endif 1097 1098 // Return "TRUE" iff the given object address is within the collection 1099 // set. Assumes that the reference points into the heap. 1100 inline bool is_in_cset(const HeapRegion *hr); 1101 inline bool is_in_cset(oop obj); 1102 inline bool is_in_cset(HeapWord* addr); 1103 1104 inline bool is_in_cset_or_humongous(const oop obj); 1105 1106 private: 1107 // This array is used for a quick test on whether a reference points into 1108 // the collection set or not. Each of the array's elements denotes whether the 1109 // corresponding region is in the collection set or not. 1110 G1HeapRegionAttrBiasedMappedArray _region_attr; 1111 1112 public: 1113 1114 inline G1HeapRegionAttr region_attr(const void* obj) const; 1115 inline G1HeapRegionAttr region_attr(uint idx) const; 1116 1117 // Return "TRUE" iff the given object address is in the reserved 1118 // region of g1. 1119 bool is_in_g1_reserved(const void* p) const { 1120 return _hrm->reserved().contains(p); 1121 } 1122 1123 // Returns a MemRegion that corresponds to the space that has been 1124 // reserved for the heap 1125 MemRegion g1_reserved() const { 1126 return _hrm->reserved(); 1127 } 1128 1129 MemRegion reserved_region() const { 1130 return _reserved; 1131 } 1132 1133 HeapWord* base() const { 1134 return _reserved.start(); 1135 } 1136 1137 bool is_in_reserved(const void* addr) const { 1138 return _reserved.contains(addr); 1139 } 1140 1141 G1HotCardCache* g1_hot_card_cache() const { return _hot_card_cache; } 1142 1143 G1CardTable* card_table() const { 1144 return _card_table; 1145 } 1146 1147 // Iteration functions. 1148 1149 // Iterate over all objects, calling "cl.do_object" on each. 1150 virtual void object_iterate(ObjectClosure* cl); 1151 1152 virtual void safe_object_iterate(ObjectClosure* cl) { 1153 object_iterate(cl); 1154 } 1155 1156 // Iterate over heap regions, in address order, terminating the 1157 // iteration early if the "do_heap_region" method returns "true". 1158 void heap_region_iterate(HeapRegionClosure* blk) const; 1159 1160 // Return the region with the given index. It assumes the index is valid. 1161 inline HeapRegion* region_at(uint index) const; 1162 inline HeapRegion* region_at_or_null(uint index) const; 1163 1164 // Return the next region (by index) that is part of the same 1165 // humongous object that hr is part of. 1166 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const; 1167 1168 // Calculate the region index of the given address. Given address must be 1169 // within the heap. 1170 inline uint addr_to_region(HeapWord* addr) const; 1171 1172 inline HeapWord* bottom_addr_for_region(uint index) const; 1173 1174 // Two functions to iterate over the heap regions in parallel. Threads 1175 // compete using the HeapRegionClaimer to claim the regions before 1176 // applying the closure on them. 1177 // The _from_worker_offset version uses the HeapRegionClaimer and 1178 // the worker id to calculate a start offset to prevent all workers to 1179 // start from the point. 1180 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl, 1181 HeapRegionClaimer* hrclaimer, 1182 uint worker_id) const; 1183 1184 void heap_region_par_iterate_from_start(HeapRegionClosure* cl, 1185 HeapRegionClaimer* hrclaimer) const; 1186 1187 // Iterate over all regions currently in the current collection set. 1188 void collection_set_iterate_all(HeapRegionClosure* blk); 1189 1190 // Iterate over the regions in the current increment of the collection set. 1191 // Starts the iteration so that the start regions of a given worker id over the 1192 // set active_workers are evenly spread across the set of collection set regions 1193 // to be iterated. 1194 // The variant with the HeapRegionClaimer guarantees that the closure will be 1195 // applied to a particular region exactly once. 1196 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) { 1197 collection_set_iterate_increment_from(blk, NULL, worker_id); 1198 } 1199 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id); 1200 1201 // Returns the HeapRegion that contains addr. addr must not be NULL. 1202 template <class T> 1203 inline HeapRegion* heap_region_containing(const T addr) const; 1204 1205 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted 1206 // region. addr must not be NULL. 1207 template <class T> 1208 inline HeapRegion* heap_region_containing_or_null(const T addr) const; 1209 1210 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1211 // each address in the (reserved) heap is a member of exactly 1212 // one block. The defining characteristic of a block is that it is 1213 // possible to find its size, and thus to progress forward to the next 1214 // block. (Blocks may be of different sizes.) Thus, blocks may 1215 // represent Java objects, or they might be free blocks in a 1216 // free-list-based heap (or subheap), as long as the two kinds are 1217 // distinguishable and the size of each is determinable. 1218 1219 // Returns the address of the start of the "block" that contains the 1220 // address "addr". We say "blocks" instead of "object" since some heaps 1221 // may not pack objects densely; a chunk may either be an object or a 1222 // non-object. 1223 HeapWord* block_start(const void* addr) const; 1224 1225 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1226 // the block is an object. 1227 bool block_is_obj(const HeapWord* addr) const; 1228 1229 // Section on thread-local allocation buffers (TLABs) 1230 // See CollectedHeap for semantics. 1231 1232 bool supports_tlab_allocation() const; 1233 size_t tlab_capacity(Thread* ignored) const; 1234 size_t tlab_used(Thread* ignored) const; 1235 size_t max_tlab_size() const; 1236 size_t unsafe_max_tlab_alloc(Thread* ignored) const; 1237 1238 inline bool is_in_young(const oop obj); 1239 1240 // Returns "true" iff the given word_size is "very large". 1241 static bool is_humongous(size_t word_size) { 1242 // Note this has to be strictly greater-than as the TLABs 1243 // are capped at the humongous threshold and we want to 1244 // ensure that we don't try to allocate a TLAB as 1245 // humongous and that we don't allocate a humongous 1246 // object in a TLAB. 1247 return word_size > _humongous_object_threshold_in_words; 1248 } 1249 1250 // Returns the humongous threshold for a specific region size 1251 static size_t humongous_threshold_for(size_t region_size) { 1252 return (region_size / 2); 1253 } 1254 1255 // Returns the number of regions the humongous object of the given word size 1256 // requires. 1257 static size_t humongous_obj_size_in_regions(size_t word_size); 1258 1259 // Print the maximum heap capacity. 1260 virtual size_t max_capacity() const; 1261 1262 // Return the size of reserved memory. Returns different value than max_capacity() when AllocateOldGenAt is used. 1263 virtual size_t max_reserved_capacity() const; 1264 1265 virtual jlong millis_since_last_gc(); 1266 1267 1268 // Convenience function to be used in situations where the heap type can be 1269 // asserted to be this type. 1270 static G1CollectedHeap* heap(); 1271 1272 void set_region_short_lived_locked(HeapRegion* hr); 1273 // add appropriate methods for any other surv rate groups 1274 1275 const G1SurvivorRegions* survivor() const { return &_survivor; } 1276 1277 uint eden_regions_count() const { return _eden.length(); } 1278 uint survivor_regions_count() const { return _survivor.length(); } 1279 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); } 1280 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); } 1281 uint young_regions_count() const { return _eden.length() + _survivor.length(); } 1282 uint old_regions_count() const { return _old_set.length(); } 1283 uint archive_regions_count() const { return _archive_set.length(); } 1284 uint humongous_regions_count() const { return _humongous_set.length(); } 1285 1286 #ifdef ASSERT 1287 bool check_young_list_empty(); 1288 #endif 1289 1290 // *** Stuff related to concurrent marking. It's not clear to me that so 1291 // many of these need to be public. 1292 1293 // The functions below are helper functions that a subclass of 1294 // "CollectedHeap" can use in the implementation of its virtual 1295 // functions. 1296 // This performs a concurrent marking of the live objects in a 1297 // bitmap off to the side. 1298 void do_concurrent_mark(); 1299 1300 bool is_marked_next(oop obj) const; 1301 1302 // Determine if an object is dead, given the object and also 1303 // the region to which the object belongs. An object is dead 1304 // iff a) it was not allocated since the last mark, b) it 1305 // is not marked, and c) it is not in an archive region. 1306 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1307 return 1308 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) && 1309 !hr->is_archive(); 1310 } 1311 1312 // This function returns true when an object has been 1313 // around since the previous marking and hasn't yet 1314 // been marked during this marking, and is not in an archive region. 1315 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1316 return 1317 !hr->obj_allocated_since_next_marking(obj) && 1318 !is_marked_next(obj) && 1319 !hr->is_archive(); 1320 } 1321 1322 // Determine if an object is dead, given only the object itself. 1323 // This will find the region to which the object belongs and 1324 // then call the region version of the same function. 1325 1326 // Added if it is NULL it isn't dead. 1327 1328 inline bool is_obj_dead(const oop obj) const; 1329 1330 inline bool is_obj_ill(const oop obj) const; 1331 1332 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const; 1333 inline bool is_obj_dead_full(const oop obj) const; 1334 1335 G1ConcurrentMark* concurrent_mark() const { return _cm; } 1336 1337 // Refinement 1338 1339 G1ConcurrentRefine* concurrent_refine() const { return _cr; } 1340 1341 // Optimized nmethod scanning support routines 1342 1343 // Register the given nmethod with the G1 heap. 1344 virtual void register_nmethod(nmethod* nm); 1345 1346 // Unregister the given nmethod from the G1 heap. 1347 virtual void unregister_nmethod(nmethod* nm); 1348 1349 // No nmethod flushing needed. 1350 virtual void flush_nmethod(nmethod* nm) {} 1351 1352 // No nmethod verification implemented. 1353 virtual void verify_nmethod(nmethod* nm) {} 1354 1355 // Free up superfluous code root memory. 1356 void purge_code_root_memory(); 1357 1358 // Rebuild the strong code root lists for each region 1359 // after a full GC. 1360 void rebuild_strong_code_roots(); 1361 1362 // Partial cleaning of VM internal data structures. 1363 void string_dedup_cleaning(BoolObjectClosure* is_alive, 1364 OopClosure* keep_alive, 1365 G1GCPhaseTimes* phase_times = NULL); 1366 1367 // Performs cleaning of data structures after class unloading. 1368 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred); 1369 1370 // Redirty logged cards in the refinement queue. 1371 void redirty_logged_cards(G1RedirtyCardsQueueSet* rdcqs); 1372 1373 // Verification 1374 1375 // Deduplicate the string 1376 virtual void deduplicate_string(oop str); 1377 1378 // Perform any cleanup actions necessary before allowing a verification. 1379 virtual void prepare_for_verify(); 1380 1381 // Perform verification. 1382 1383 // vo == UsePrevMarking -> use "prev" marking information, 1384 // vo == UseNextMarking -> use "next" marking information 1385 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS 1386 // 1387 // NOTE: Only the "prev" marking information is guaranteed to be 1388 // consistent most of the time, so most calls to this should use 1389 // vo == UsePrevMarking. 1390 // Currently, there is only one case where this is called with 1391 // vo == UseNextMarking, which is to verify the "next" marking 1392 // information at the end of remark. 1393 // Currently there is only one place where this is called with 1394 // vo == UseFullMarking, which is to verify the marking during a 1395 // full GC. 1396 void verify(VerifyOption vo); 1397 1398 // WhiteBox testing support. 1399 virtual bool supports_concurrent_phase_control() const; 1400 virtual bool request_concurrent_phase(const char* phase); 1401 bool is_heterogeneous_heap() const; 1402 1403 virtual WorkGang* get_safepoint_workers() { return _workers; } 1404 1405 // The methods below are here for convenience and dispatch the 1406 // appropriate method depending on value of the given VerifyOption 1407 // parameter. The values for that parameter, and their meanings, 1408 // are the same as those above. 1409 1410 bool is_obj_dead_cond(const oop obj, 1411 const HeapRegion* hr, 1412 const VerifyOption vo) const; 1413 1414 bool is_obj_dead_cond(const oop obj, 1415 const VerifyOption vo) const; 1416 1417 G1HeapSummary create_g1_heap_summary(); 1418 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats); 1419 1420 // Printing 1421 private: 1422 void print_heap_regions() const; 1423 void print_regions_on(outputStream* st) const; 1424 1425 public: 1426 virtual void print_on(outputStream* st) const; 1427 virtual void print_extended_on(outputStream* st) const; 1428 virtual void print_on_error(outputStream* st) const; 1429 1430 virtual void print_gc_threads_on(outputStream* st) const; 1431 virtual void gc_threads_do(ThreadClosure* tc) const; 1432 1433 // Override 1434 void print_tracing_info() const; 1435 1436 // The following two methods are helpful for debugging RSet issues. 1437 void print_cset_rsets() PRODUCT_RETURN; 1438 void print_all_rsets() PRODUCT_RETURN; 1439 1440 // Used to print information about locations in the hs_err file. 1441 virtual bool print_location(outputStream* st, void* addr) const; 1442 1443 size_t pending_card_num(); 1444 }; 1445 1446 class G1ParEvacuateFollowersClosure : public VoidClosure { 1447 private: 1448 double _start_term; 1449 double _term_time; 1450 size_t _term_attempts; 1451 1452 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); } 1453 void end_term_time() { _term_time += (os::elapsedTime() - _start_term); } 1454 protected: 1455 G1CollectedHeap* _g1h; 1456 G1ParScanThreadState* _par_scan_state; 1457 RefToScanQueueSet* _queues; 1458 ParallelTaskTerminator* _terminator; 1459 G1GCPhaseTimes::GCParPhases _phase; 1460 1461 G1ParScanThreadState* par_scan_state() { return _par_scan_state; } 1462 RefToScanQueueSet* queues() { return _queues; } 1463 ParallelTaskTerminator* terminator() { return _terminator; } 1464 1465 public: 1466 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h, 1467 G1ParScanThreadState* par_scan_state, 1468 RefToScanQueueSet* queues, 1469 ParallelTaskTerminator* terminator, 1470 G1GCPhaseTimes::GCParPhases phase) 1471 : _start_term(0.0), _term_time(0.0), _term_attempts(0), 1472 _g1h(g1h), _par_scan_state(par_scan_state), 1473 _queues(queues), _terminator(terminator), _phase(phase) {} 1474 1475 void do_void(); 1476 1477 double term_time() const { return _term_time; } 1478 size_t term_attempts() const { return _term_attempts; } 1479 1480 private: 1481 inline bool offer_termination(); 1482 }; 1483 1484 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP