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/g1MemoryNodeManager.hpp" 44 #include "gc/g1/g1MonitoringSupport.hpp" 45 #include "gc/g1/g1RedirtyCardsQueue.hpp" 46 #include "gc/g1/g1SurvivorRegions.hpp" 47 #include "gc/g1/g1YCTypes.hpp" 48 #include "gc/g1/heapRegionManager.hpp" 49 #include "gc/g1/heapRegionSet.hpp" 50 #include "gc/g1/heterogeneousHeapRegionManager.hpp" 51 #include "gc/shared/barrierSet.hpp" 52 #include "gc/shared/collectedHeap.hpp" 53 #include "gc/shared/gcHeapSummary.hpp" 54 #include "gc/shared/plab.hpp" 55 #include "gc/shared/preservedMarks.hpp" 56 #include "gc/shared/softRefPolicy.hpp" 57 #include "memory/memRegion.hpp" 58 #include "utilities/stack.hpp" 59 60 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot. 61 // It uses the "Garbage First" heap organization and algorithm, which 62 // may combine concurrent marking with parallel, incremental compaction of 63 // heap subsets that will yield large amounts of garbage. 64 65 // Forward declarations 66 class HeapRegion; 67 class GenerationSpec; 68 class G1ParScanThreadState; 69 class G1ParScanThreadStateSet; 70 class G1ParScanThreadState; 71 class MemoryPool; 72 class MemoryManager; 73 class ObjectClosure; 74 class SpaceClosure; 75 class CompactibleSpaceClosure; 76 class Space; 77 class G1CardTableEntryClosure; 78 class G1CollectionSet; 79 class G1Policy; 80 class G1HotCardCache; 81 class G1RemSet; 82 class G1YoungRemSetSamplingThread; 83 class G1ConcurrentMark; 84 class G1ConcurrentMarkThread; 85 class G1ConcurrentRefine; 86 class GenerationCounters; 87 class STWGCTimer; 88 class G1NewTracer; 89 class EvacuationFailedInfo; 90 class nmethod; 91 class WorkGang; 92 class G1Allocator; 93 class G1ArchiveAllocator; 94 class G1FullGCScope; 95 class G1HeapVerifier; 96 class G1HeapSizingPolicy; 97 class G1HeapSummary; 98 class G1EvacSummary; 99 100 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue; 101 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet; 102 103 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() ) 104 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion ) 105 106 // The G1 STW is alive closure. 107 // An instance is embedded into the G1CH and used as the 108 // (optional) _is_alive_non_header closure in the STW 109 // reference processor. It is also extensively used during 110 // reference processing during STW evacuation pauses. 111 class G1STWIsAliveClosure : public BoolObjectClosure { 112 G1CollectedHeap* _g1h; 113 public: 114 G1STWIsAliveClosure(G1CollectedHeap* g1h) : _g1h(g1h) {} 115 bool do_object_b(oop p); 116 }; 117 118 class G1STWSubjectToDiscoveryClosure : public BoolObjectClosure { 119 G1CollectedHeap* _g1h; 120 public: 121 G1STWSubjectToDiscoveryClosure(G1CollectedHeap* g1h) : _g1h(g1h) {} 122 bool do_object_b(oop p); 123 }; 124 125 class G1RegionMappingChangedListener : public G1MappingChangedListener { 126 private: 127 void reset_from_card_cache(uint start_idx, size_t num_regions); 128 public: 129 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 130 }; 131 132 class G1CollectedHeap : public CollectedHeap { 133 friend class G1FreeCollectionSetTask; 134 friend class VM_CollectForMetadataAllocation; 135 friend class VM_G1CollectForAllocation; 136 friend class VM_G1CollectFull; 137 friend class VMStructs; 138 friend class MutatorAllocRegion; 139 friend class G1FullCollector; 140 friend class G1GCAllocRegion; 141 friend class G1HeapVerifier; 142 143 // Closures used in implementation. 144 friend class G1ParScanThreadState; 145 friend class G1ParScanThreadStateSet; 146 friend class G1EvacuateRegionsTask; 147 friend class G1PLABAllocator; 148 149 // Other related classes. 150 friend class HeapRegionClaimer; 151 152 // Testing classes. 153 friend class G1CheckRegionAttrTableClosure; 154 155 private: 156 G1YoungRemSetSamplingThread* _young_gen_sampling_thread; 157 158 WorkGang* _workers; 159 G1CardTable* _card_table; 160 161 SoftRefPolicy _soft_ref_policy; 162 163 static size_t _humongous_object_threshold_in_words; 164 165 // These sets keep track of old, archive and humongous regions respectively. 166 HeapRegionSet _old_set; 167 HeapRegionSet _archive_set; 168 HeapRegionSet _humongous_set; 169 170 void eagerly_reclaim_humongous_regions(); 171 // Start a new incremental collection set for the next pause. 172 void start_new_collection_set(); 173 174 // The block offset table for the G1 heap. 175 G1BlockOffsetTable* _bot; 176 177 // Tears down the region sets / lists so that they are empty and the 178 // regions on the heap do not belong to a region set / list. The 179 // only exception is the humongous set which we leave unaltered. If 180 // free_list_only is true, it will only tear down the master free 181 // list. It is called before a Full GC (free_list_only == false) or 182 // before heap shrinking (free_list_only == true). 183 void tear_down_region_sets(bool free_list_only); 184 185 // Rebuilds the region sets / lists so that they are repopulated to 186 // reflect the contents of the heap. The only exception is the 187 // humongous set which was not torn down in the first place. If 188 // free_list_only is true, it will only rebuild the master free 189 // list. It is called after a Full GC (free_list_only == false) or 190 // after heap shrinking (free_list_only == true). 191 void rebuild_region_sets(bool free_list_only); 192 193 // Callback for region mapping changed events. 194 G1RegionMappingChangedListener _listener; 195 196 // Manages single or multi node memory. 197 G1MemoryNodeManager* _mem_node_mgr; 198 199 // The sequence of all heap regions in the heap. 200 HeapRegionManager* _hrm; 201 202 // Manages all allocations with regions except humongous object allocations. 203 G1Allocator* _allocator; 204 205 // Manages all heap verification. 206 G1HeapVerifier* _verifier; 207 208 // Outside of GC pauses, the number of bytes used in all regions other 209 // than the current allocation region(s). 210 volatile size_t _summary_bytes_used; 211 212 void increase_used(size_t bytes); 213 void decrease_used(size_t bytes); 214 215 void set_used(size_t bytes); 216 217 // Class that handles archive allocation ranges. 218 G1ArchiveAllocator* _archive_allocator; 219 220 // GC allocation statistics policy for survivors. 221 G1EvacStats _survivor_evac_stats; 222 223 // GC allocation statistics policy for tenured objects. 224 G1EvacStats _old_evac_stats; 225 226 // It specifies whether we should attempt to expand the heap after a 227 // region allocation failure. If heap expansion fails we set this to 228 // false so that we don't re-attempt the heap expansion (it's likely 229 // that subsequent expansion attempts will also fail if one fails). 230 // Currently, it is only consulted during GC and it's reset at the 231 // start of each GC. 232 bool _expand_heap_after_alloc_failure; 233 234 // Helper for monitoring and management support. 235 G1MonitoringSupport* _g1mm; 236 237 // Records whether the region at the given index is (still) a 238 // candidate for eager reclaim. Only valid for humongous start 239 // regions; other regions have unspecified values. Humongous start 240 // regions are initialized at start of collection pause, with 241 // candidates removed from the set as they are found reachable from 242 // roots or the young generation. 243 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> { 244 protected: 245 bool default_value() const { return false; } 246 public: 247 void clear() { G1BiasedMappedArray<bool>::clear(); } 248 void set_candidate(uint region, bool value) { 249 set_by_index(region, value); 250 } 251 bool is_candidate(uint region) { 252 return get_by_index(region); 253 } 254 }; 255 256 HumongousReclaimCandidates _humongous_reclaim_candidates; 257 // Stores whether during humongous object registration we found candidate regions. 258 // If not, we can skip a few steps. 259 bool _has_humongous_reclaim_candidates; 260 261 G1HRPrinter _hr_printer; 262 263 // It decides whether an explicit GC should start a concurrent cycle 264 // instead of doing a STW GC. Currently, a concurrent cycle is 265 // explicitly started if: 266 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or 267 // (b) cause == _g1_humongous_allocation 268 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent. 269 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent. 270 // (e) cause == _wb_conc_mark 271 bool should_do_concurrent_full_gc(GCCause::Cause cause); 272 273 // Return true if should upgrade to full gc after an incremental one. 274 bool should_upgrade_to_full_gc(GCCause::Cause cause); 275 276 // indicates whether we are in young or mixed GC mode 277 G1CollectorState _collector_state; 278 279 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 280 // concurrent cycles) we have started. 281 volatile uint _old_marking_cycles_started; 282 283 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 284 // concurrent cycles) we have completed. 285 volatile uint _old_marking_cycles_completed; 286 287 // This is a non-product method that is helpful for testing. It is 288 // called at the end of a GC and artificially expands the heap by 289 // allocating a number of dead regions. This way we can induce very 290 // frequent marking cycles and stress the cleanup / concurrent 291 // cleanup code more (as all the regions that will be allocated by 292 // this method will be found dead by the marking cycle). 293 void allocate_dummy_regions() PRODUCT_RETURN; 294 295 // If the HR printer is active, dump the state of the regions in the 296 // heap after a compaction. 297 void print_hrm_post_compaction(); 298 299 // Create a memory mapper for auxiliary data structures of the given size and 300 // translation factor. 301 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description, 302 size_t size, 303 size_t translation_factor); 304 305 void trace_heap(GCWhen::Type when, const GCTracer* tracer); 306 307 // These are macros so that, if the assert fires, we get the correct 308 // line number, file, etc. 309 310 #define heap_locking_asserts_params(_extra_message_) \ 311 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 312 (_extra_message_), \ 313 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 314 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 315 BOOL_TO_STR(Thread::current()->is_VM_thread()) 316 317 #define assert_heap_locked() \ 318 do { \ 319 assert(Heap_lock->owned_by_self(), \ 320 heap_locking_asserts_params("should be holding the Heap_lock")); \ 321 } while (0) 322 323 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 324 do { \ 325 assert(Heap_lock->owned_by_self() || \ 326 (SafepointSynchronize::is_at_safepoint() && \ 327 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 328 heap_locking_asserts_params("should be holding the Heap_lock or " \ 329 "should be at a safepoint")); \ 330 } while (0) 331 332 #define assert_heap_locked_and_not_at_safepoint() \ 333 do { \ 334 assert(Heap_lock->owned_by_self() && \ 335 !SafepointSynchronize::is_at_safepoint(), \ 336 heap_locking_asserts_params("should be holding the Heap_lock and " \ 337 "should not be at a safepoint")); \ 338 } while (0) 339 340 #define assert_heap_not_locked() \ 341 do { \ 342 assert(!Heap_lock->owned_by_self(), \ 343 heap_locking_asserts_params("should not be holding the Heap_lock")); \ 344 } while (0) 345 346 #define assert_heap_not_locked_and_not_at_safepoint() \ 347 do { \ 348 assert(!Heap_lock->owned_by_self() && \ 349 !SafepointSynchronize::is_at_safepoint(), \ 350 heap_locking_asserts_params("should not be holding the Heap_lock and " \ 351 "should not be at a safepoint")); \ 352 } while (0) 353 354 #define assert_at_safepoint_on_vm_thread() \ 355 do { \ 356 assert_at_safepoint(); \ 357 assert(Thread::current_or_null() != NULL, "no current thread"); \ 358 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \ 359 } while (0) 360 361 #ifdef ASSERT 362 #define assert_used_and_recalculate_used_equal(g1h) \ 363 do { \ 364 size_t cur_used_bytes = g1h->used(); \ 365 size_t recal_used_bytes = g1h->recalculate_used(); \ 366 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \ 367 " same as recalculated used(" SIZE_FORMAT ").", \ 368 cur_used_bytes, recal_used_bytes); \ 369 } while (0) 370 #else 371 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0) 372 #endif 373 374 const char* young_gc_name() const; 375 376 // The young region list. 377 G1EdenRegions _eden; 378 G1SurvivorRegions _survivor; 379 380 STWGCTimer* _gc_timer_stw; 381 382 G1NewTracer* _gc_tracer_stw; 383 384 // The current policy object for the collector. 385 G1Policy* _policy; 386 G1HeapSizingPolicy* _heap_sizing_policy; 387 388 G1CollectionSet _collection_set; 389 390 // Try to allocate a single non-humongous HeapRegion sufficient for 391 // an allocation of the given word_size. If do_expand is true, 392 // attempt to expand the heap if necessary to satisfy the allocation 393 // request. 'type' takes the type of region to be allocated. (Use constants 394 // Old, Eden, Humongous, Survivor defined in HeapRegionType.) 395 HeapRegion* new_region(size_t word_size, 396 HeapRegionType type, 397 bool do_expand, 398 uint node_index = G1MemoryNodeManager::AnyNodeIndex); 399 400 // Initialize a contiguous set of free regions of length num_regions 401 // and starting at index first so that they appear as a single 402 // humongous region. 403 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 404 uint num_regions, 405 size_t word_size); 406 407 // Attempt to allocate a humongous object of the given size. Return 408 // NULL if unsuccessful. 409 HeapWord* humongous_obj_allocate(size_t word_size); 410 411 // The following two methods, allocate_new_tlab() and 412 // mem_allocate(), are the two main entry points from the runtime 413 // into the G1's allocation routines. They have the following 414 // assumptions: 415 // 416 // * They should both be called outside safepoints. 417 // 418 // * They should both be called without holding the Heap_lock. 419 // 420 // * All allocation requests for new TLABs should go to 421 // allocate_new_tlab(). 422 // 423 // * All non-TLAB allocation requests should go to mem_allocate(). 424 // 425 // * If either call cannot satisfy the allocation request using the 426 // current allocating region, they will try to get a new one. If 427 // this fails, they will attempt to do an evacuation pause and 428 // retry the allocation. 429 // 430 // * If all allocation attempts fail, even after trying to schedule 431 // an evacuation pause, allocate_new_tlab() will return NULL, 432 // whereas mem_allocate() will attempt a heap expansion and/or 433 // schedule a Full GC. 434 // 435 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 436 // should never be called with word_size being humongous. All 437 // humongous allocation requests should go to mem_allocate() which 438 // will satisfy them with a special path. 439 440 virtual HeapWord* allocate_new_tlab(size_t min_size, 441 size_t requested_size, 442 size_t* actual_size); 443 444 virtual HeapWord* mem_allocate(size_t word_size, 445 bool* gc_overhead_limit_was_exceeded); 446 447 // First-level mutator allocation attempt: try to allocate out of 448 // the mutator alloc region without taking the Heap_lock. This 449 // should only be used for non-humongous allocations. 450 inline HeapWord* attempt_allocation(size_t min_word_size, 451 size_t desired_word_size, 452 size_t* actual_word_size); 453 454 // Second-level mutator allocation attempt: take the Heap_lock and 455 // retry the allocation attempt, potentially scheduling a GC 456 // pause. This should only be used for non-humongous allocations. 457 HeapWord* attempt_allocation_slow(size_t word_size); 458 459 // Takes the Heap_lock and attempts a humongous allocation. It can 460 // potentially schedule a GC pause. 461 HeapWord* attempt_allocation_humongous(size_t word_size); 462 463 // Allocation attempt that should be called during safepoints (e.g., 464 // at the end of a successful GC). expect_null_mutator_alloc_region 465 // specifies whether the mutator alloc region is expected to be NULL 466 // or not. 467 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 468 bool expect_null_mutator_alloc_region); 469 470 // These methods are the "callbacks" from the G1AllocRegion class. 471 472 // For mutator alloc regions. 473 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index); 474 void retire_mutator_alloc_region(HeapRegion* alloc_region, 475 size_t allocated_bytes); 476 477 // For GC alloc regions. 478 bool has_more_regions(G1HeapRegionAttr dest); 479 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest); 480 void retire_gc_alloc_region(HeapRegion* alloc_region, 481 size_t allocated_bytes, G1HeapRegionAttr dest); 482 483 // - if explicit_gc is true, the GC is for a System.gc() etc, 484 // otherwise it's for a failed allocation. 485 // - if clear_all_soft_refs is true, all soft references should be 486 // cleared during the GC. 487 // - it returns false if it is unable to do the collection due to the 488 // GC locker being active, true otherwise. 489 bool do_full_collection(bool explicit_gc, 490 bool clear_all_soft_refs); 491 492 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread. 493 virtual void do_full_collection(bool clear_all_soft_refs); 494 495 // Callback from VM_G1CollectForAllocation operation. 496 // This function does everything necessary/possible to satisfy a 497 // failed allocation request (including collection, expansion, etc.) 498 HeapWord* satisfy_failed_allocation(size_t word_size, 499 bool* succeeded); 500 // Internal helpers used during full GC to split it up to 501 // increase readability. 502 void abort_concurrent_cycle(); 503 void verify_before_full_collection(bool explicit_gc); 504 void prepare_heap_for_full_collection(); 505 void prepare_heap_for_mutators(); 506 void abort_refinement(); 507 void verify_after_full_collection(); 508 void print_heap_after_full_collection(G1HeapTransition* heap_transition); 509 510 // Helper method for satisfy_failed_allocation() 511 HeapWord* satisfy_failed_allocation_helper(size_t word_size, 512 bool do_gc, 513 bool clear_all_soft_refs, 514 bool expect_null_mutator_alloc_region, 515 bool* gc_succeeded); 516 517 // Attempting to expand the heap sufficiently 518 // to support an allocation of the given "word_size". If 519 // successful, perform the allocation and return the address of the 520 // allocated block, or else "NULL". 521 HeapWord* expand_and_allocate(size_t word_size); 522 523 // Process any reference objects discovered. 524 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states); 525 526 // If during an initial mark pause we may install a pending list head which is not 527 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking 528 // to discover. 529 void make_pending_list_reachable(); 530 531 // Merges the information gathered on a per-thread basis for all worker threads 532 // during GC into global variables. 533 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states); 534 public: 535 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; } 536 537 WorkGang* workers() const { return _workers; } 538 539 // Runs the given AbstractGangTask with the current active workers, returning the 540 // total time taken. 541 Tickspan run_task(AbstractGangTask* task); 542 543 G1Allocator* allocator() { 544 return _allocator; 545 } 546 547 G1HeapVerifier* verifier() { 548 return _verifier; 549 } 550 551 G1MonitoringSupport* g1mm() { 552 assert(_g1mm != NULL, "should have been initialized"); 553 return _g1mm; 554 } 555 556 void resize_heap_if_necessary(); 557 558 G1MemoryNodeManager* mem_node_mgr() const { return _mem_node_mgr; } 559 560 // Expand the garbage-first heap by at least the given size (in bytes!). 561 // Returns true if the heap was expanded by the requested amount; 562 // false otherwise. 563 // (Rounds up to a HeapRegion boundary.) 564 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL); 565 bool expand_single_region(uint node_index); 566 567 // Returns the PLAB statistics for a given destination. 568 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest); 569 570 // Determines PLAB size for a given destination. 571 inline size_t desired_plab_sz(G1HeapRegionAttr dest); 572 573 // Do anything common to GC's. 574 void gc_prologue(bool full); 575 void gc_epilogue(bool full); 576 577 // Does the given region fulfill remembered set based eager reclaim candidate requirements? 578 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const; 579 580 // Modify the reclaim candidate set and test for presence. 581 // These are only valid for starts_humongous regions. 582 inline void set_humongous_reclaim_candidate(uint region, bool value); 583 inline bool is_humongous_reclaim_candidate(uint region); 584 585 // Remove from the reclaim candidate set. Also remove from the 586 // collection set so that later encounters avoid the slow path. 587 inline void set_humongous_is_live(oop obj); 588 589 // Register the given region to be part of the collection set. 590 inline void register_humongous_region_with_region_attr(uint index); 591 // Update region attributes table with information about all regions. 592 void register_regions_with_region_attr(); 593 // We register a region with the fast "in collection set" test. We 594 // simply set to true the array slot corresponding to this region. 595 void register_young_region_with_region_attr(HeapRegion* r) { 596 _region_attr.set_in_young(r->hrm_index()); 597 } 598 inline void register_region_with_region_attr(HeapRegion* r); 599 inline void register_old_region_with_region_attr(HeapRegion* r); 600 inline void register_optional_region_with_region_attr(HeapRegion* r); 601 602 void clear_region_attr(const HeapRegion* hr) { 603 _region_attr.clear(hr); 604 } 605 606 void clear_region_attr() { 607 _region_attr.clear(); 608 } 609 610 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking 611 // for all regions. 612 void verify_region_attr_remset_update() PRODUCT_RETURN; 613 614 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause); 615 616 // This is called at the start of either a concurrent cycle or a Full 617 // GC to update the number of old marking cycles started. 618 void increment_old_marking_cycles_started(); 619 620 // This is called at the end of either a concurrent cycle or a Full 621 // GC to update the number of old marking cycles completed. Those two 622 // can happen in a nested fashion, i.e., we start a concurrent 623 // cycle, a Full GC happens half-way through it which ends first, 624 // and then the cycle notices that a Full GC happened and ends 625 // too. The concurrent parameter is a boolean to help us do a bit 626 // tighter consistency checking in the method. If concurrent is 627 // false, the caller is the inner caller in the nesting (i.e., the 628 // Full GC). If concurrent is true, the caller is the outer caller 629 // in this nesting (i.e., the concurrent cycle). Further nesting is 630 // not currently supported. The end of this call also notifies 631 // the FullGCCount_lock in case a Java thread is waiting for a full 632 // GC to happen (e.g., it called System.gc() with 633 // +ExplicitGCInvokesConcurrent). 634 void increment_old_marking_cycles_completed(bool concurrent); 635 636 uint old_marking_cycles_completed() { 637 return _old_marking_cycles_completed; 638 } 639 640 G1HRPrinter* hr_printer() { return &_hr_printer; } 641 642 // Allocates a new heap region instance. 643 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr); 644 645 // Allocate the highest free region in the reserved heap. This will commit 646 // regions as necessary. 647 HeapRegion* alloc_highest_free_region(); 648 649 // Frees a non-humongous region by initializing its contents and 650 // adding it to the free list that's passed as a parameter (this is 651 // usually a local list which will be appended to the master free 652 // list later). The used bytes of freed regions are accumulated in 653 // pre_used. If skip_remset is true, the region's RSet will not be freed 654 // up. If skip_hot_card_cache is true, the region's hot card cache will not 655 // be freed up. The assumption is that this will be done later. 656 // The locked parameter indicates if the caller has already taken 657 // care of proper synchronization. This may allow some optimizations. 658 void free_region(HeapRegion* hr, 659 FreeRegionList* free_list, 660 bool skip_remset, 661 bool skip_hot_card_cache = false, 662 bool locked = false); 663 664 // It dirties the cards that cover the block so that the post 665 // write barrier never queues anything when updating objects on this 666 // block. It is assumed (and in fact we assert) that the block 667 // belongs to a young region. 668 inline void dirty_young_block(HeapWord* start, size_t word_size); 669 670 // Frees a humongous region by collapsing it into individual regions 671 // and calling free_region() for each of them. The freed regions 672 // will be added to the free list that's passed as a parameter (this 673 // is usually a local list which will be appended to the master free 674 // list later). 675 // The method assumes that only a single thread is ever calling 676 // this for a particular region at once. 677 void free_humongous_region(HeapRegion* hr, 678 FreeRegionList* free_list); 679 680 // Facility for allocating in 'archive' regions in high heap memory and 681 // recording the allocated ranges. These should all be called from the 682 // VM thread at safepoints, without the heap lock held. They can be used 683 // to create and archive a set of heap regions which can be mapped at the 684 // same fixed addresses in a subsequent JVM invocation. 685 void begin_archive_alloc_range(bool open = false); 686 687 // Check if the requested size would be too large for an archive allocation. 688 bool is_archive_alloc_too_large(size_t word_size); 689 690 // Allocate memory of the requested size from the archive region. This will 691 // return NULL if the size is too large or if no memory is available. It 692 // does not trigger a garbage collection. 693 HeapWord* archive_mem_allocate(size_t word_size); 694 695 // Optionally aligns the end address and returns the allocated ranges in 696 // an array of MemRegions in order of ascending addresses. 697 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges, 698 size_t end_alignment_in_bytes = 0); 699 700 // Facility for allocating a fixed range within the heap and marking 701 // the containing regions as 'archive'. For use at JVM init time, when the 702 // caller may mmap archived heap data at the specified range(s). 703 // Verify that the MemRegions specified in the argument array are within the 704 // reserved heap. 705 bool check_archive_addresses(MemRegion* range, size_t count); 706 707 // Commit the appropriate G1 regions containing the specified MemRegions 708 // and mark them as 'archive' regions. The regions in the array must be 709 // non-overlapping and in order of ascending address. 710 bool alloc_archive_regions(MemRegion* range, size_t count, bool open); 711 712 // Insert any required filler objects in the G1 regions around the specified 713 // ranges to make the regions parseable. This must be called after 714 // alloc_archive_regions, and after class loading has occurred. 715 void fill_archive_regions(MemRegion* range, size_t count); 716 717 // For each of the specified MemRegions, uncommit the containing G1 regions 718 // which had been allocated by alloc_archive_regions. This should be called 719 // rather than fill_archive_regions at JVM init time if the archive file 720 // mapping failed, with the same non-overlapping and sorted MemRegion array. 721 void dealloc_archive_regions(MemRegion* range, size_t count, bool is_open); 722 723 oop materialize_archived_object(oop obj); 724 725 private: 726 727 // Shrink the garbage-first heap by at most the given size (in bytes!). 728 // (Rounds down to a HeapRegion boundary.) 729 void shrink(size_t expand_bytes); 730 void shrink_helper(size_t expand_bytes); 731 732 #if TASKQUEUE_STATS 733 static void print_taskqueue_stats_hdr(outputStream* const st); 734 void print_taskqueue_stats() const; 735 void reset_taskqueue_stats(); 736 #endif // TASKQUEUE_STATS 737 738 // Schedule the VM operation that will do an evacuation pause to 739 // satisfy an allocation request of word_size. *succeeded will 740 // return whether the VM operation was successful (it did do an 741 // evacuation pause) or not (another thread beat us to it or the GC 742 // locker was active). Given that we should not be holding the 743 // Heap_lock when we enter this method, we will pass the 744 // gc_count_before (i.e., total_collections()) as a parameter since 745 // it has to be read while holding the Heap_lock. Currently, both 746 // methods that call do_collection_pause() release the Heap_lock 747 // before the call, so it's easy to read gc_count_before just before. 748 HeapWord* do_collection_pause(size_t word_size, 749 uint gc_count_before, 750 bool* succeeded, 751 GCCause::Cause gc_cause); 752 753 void wait_for_root_region_scanning(); 754 755 // The guts of the incremental collection pause, executed by the vm 756 // thread. It returns false if it is unable to do the collection due 757 // to the GC locker being active, true otherwise 758 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 759 760 G1HeapVerifier::G1VerifyType young_collection_verify_type() const; 761 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type); 762 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type); 763 764 void calculate_collection_set(G1EvacuationInfo& evacuation_info, double target_pause_time_ms); 765 766 // Actually do the work of evacuating the parts of the collection set. 767 void evacuate_initial_collection_set(G1ParScanThreadStateSet* per_thread_states); 768 void evacuate_optional_collection_set(G1ParScanThreadStateSet* per_thread_states); 769 private: 770 // Evacuate the next set of optional regions. 771 void evacuate_next_optional_regions(G1ParScanThreadStateSet* per_thread_states); 772 773 public: 774 void pre_evacuate_collection_set(G1EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss); 775 void post_evacuate_collection_set(G1EvacuationInfo& evacuation_info, 776 G1RedirtyCardsQueueSet* rdcqs, 777 G1ParScanThreadStateSet* pss); 778 779 void expand_heap_after_young_collection(); 780 // Update object copying statistics. 781 void record_obj_copy_mem_stats(); 782 783 // The hot card cache for remembered set insertion optimization. 784 G1HotCardCache* _hot_card_cache; 785 786 // The g1 remembered set of the heap. 787 G1RemSet* _rem_set; 788 789 // After a collection pause, convert the regions in the collection set into free 790 // regions. 791 void free_collection_set(G1CollectionSet* collection_set, G1EvacuationInfo& evacuation_info, const size_t* surviving_young_words); 792 793 // Abandon the current collection set without recording policy 794 // statistics or updating free lists. 795 void abandon_collection_set(G1CollectionSet* collection_set); 796 797 // The concurrent marker (and the thread it runs in.) 798 G1ConcurrentMark* _cm; 799 G1ConcurrentMarkThread* _cm_thread; 800 801 // The concurrent refiner. 802 G1ConcurrentRefine* _cr; 803 804 // The parallel task queues 805 RefToScanQueueSet *_task_queues; 806 807 // True iff a evacuation has failed in the current collection. 808 bool _evacuation_failed; 809 810 EvacuationFailedInfo* _evacuation_failed_info_array; 811 812 // Failed evacuations cause some logical from-space objects to have 813 // forwarding pointers to themselves. Reset them. 814 void remove_self_forwarding_pointers(G1RedirtyCardsQueueSet* rdcqs); 815 816 // Restore the objects in the regions in the collection set after an 817 // evacuation failure. 818 void restore_after_evac_failure(G1RedirtyCardsQueueSet* rdcqs); 819 820 PreservedMarksSet _preserved_marks_set; 821 822 // Preserve the mark of "obj", if necessary, in preparation for its mark 823 // word being overwritten with a self-forwarding-pointer. 824 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markWord m); 825 826 #ifndef PRODUCT 827 // Support for forcing evacuation failures. Analogous to 828 // PromotionFailureALot for the other collectors. 829 830 // Records whether G1EvacuationFailureALot should be in effect 831 // for the current GC 832 bool _evacuation_failure_alot_for_current_gc; 833 834 // Used to record the GC number for interval checking when 835 // determining whether G1EvaucationFailureALot is in effect 836 // for the current GC. 837 size_t _evacuation_failure_alot_gc_number; 838 839 // Count of the number of evacuations between failures. 840 volatile size_t _evacuation_failure_alot_count; 841 842 // Set whether G1EvacuationFailureALot should be in effect 843 // for the current GC (based upon the type of GC and which 844 // command line flags are set); 845 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc, 846 bool during_initial_mark, 847 bool mark_or_rebuild_in_progress); 848 849 inline void set_evacuation_failure_alot_for_current_gc(); 850 851 // Return true if it's time to cause an evacuation failure. 852 inline bool evacuation_should_fail(); 853 854 // Reset the G1EvacuationFailureALot counters. Should be called at 855 // the end of an evacuation pause in which an evacuation failure occurred. 856 inline void reset_evacuation_should_fail(); 857 #endif // !PRODUCT 858 859 // ("Weak") Reference processing support. 860 // 861 // G1 has 2 instances of the reference processor class. One 862 // (_ref_processor_cm) handles reference object discovery 863 // and subsequent processing during concurrent marking cycles. 864 // 865 // The other (_ref_processor_stw) handles reference object 866 // discovery and processing during full GCs and incremental 867 // evacuation pauses. 868 // 869 // During an incremental pause, reference discovery will be 870 // temporarily disabled for _ref_processor_cm and will be 871 // enabled for _ref_processor_stw. At the end of the evacuation 872 // pause references discovered by _ref_processor_stw will be 873 // processed and discovery will be disabled. The previous 874 // setting for reference object discovery for _ref_processor_cm 875 // will be re-instated. 876 // 877 // At the start of marking: 878 // * Discovery by the CM ref processor is verified to be inactive 879 // and it's discovered lists are empty. 880 // * Discovery by the CM ref processor is then enabled. 881 // 882 // At the end of marking: 883 // * Any references on the CM ref processor's discovered 884 // lists are processed (possibly MT). 885 // 886 // At the start of full GC we: 887 // * Disable discovery by the CM ref processor and 888 // empty CM ref processor's discovered lists 889 // (without processing any entries). 890 // * Verify that the STW ref processor is inactive and it's 891 // discovered lists are empty. 892 // * Temporarily set STW ref processor discovery as single threaded. 893 // * Temporarily clear the STW ref processor's _is_alive_non_header 894 // field. 895 // * Finally enable discovery by the STW ref processor. 896 // 897 // The STW ref processor is used to record any discovered 898 // references during the full GC. 899 // 900 // At the end of a full GC we: 901 // * Enqueue any reference objects discovered by the STW ref processor 902 // that have non-live referents. This has the side-effect of 903 // making the STW ref processor inactive by disabling discovery. 904 // * Verify that the CM ref processor is still inactive 905 // and no references have been placed on it's discovered 906 // lists (also checked as a precondition during initial marking). 907 908 // The (stw) reference processor... 909 ReferenceProcessor* _ref_processor_stw; 910 911 // During reference object discovery, the _is_alive_non_header 912 // closure (if non-null) is applied to the referent object to 913 // determine whether the referent is live. If so then the 914 // reference object does not need to be 'discovered' and can 915 // be treated as a regular oop. This has the benefit of reducing 916 // the number of 'discovered' reference objects that need to 917 // be processed. 918 // 919 // Instance of the is_alive closure for embedding into the 920 // STW reference processor as the _is_alive_non_header field. 921 // Supplying a value for the _is_alive_non_header field is 922 // optional but doing so prevents unnecessary additions to 923 // the discovered lists during reference discovery. 924 G1STWIsAliveClosure _is_alive_closure_stw; 925 926 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw; 927 928 // The (concurrent marking) reference processor... 929 ReferenceProcessor* _ref_processor_cm; 930 931 // Instance of the concurrent mark is_alive closure for embedding 932 // into the Concurrent Marking reference processor as the 933 // _is_alive_non_header field. Supplying a value for the 934 // _is_alive_non_header field is optional but doing so prevents 935 // unnecessary additions to the discovered lists during reference 936 // discovery. 937 G1CMIsAliveClosure _is_alive_closure_cm; 938 939 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm; 940 public: 941 RefToScanQueue *task_queue(uint i) const; 942 943 uint num_task_queues() const; 944 945 // Create a G1CollectedHeap. 946 // Must call the initialize method afterwards. 947 // May not return if something goes wrong. 948 G1CollectedHeap(); 949 950 private: 951 jint initialize_concurrent_refinement(); 952 jint initialize_young_gen_sampling_thread(); 953 public: 954 // Initialize the G1CollectedHeap to have the initial and 955 // maximum sizes and remembered and barrier sets 956 // specified by the policy object. 957 jint initialize(); 958 959 virtual void stop(); 960 virtual void safepoint_synchronize_begin(); 961 virtual void safepoint_synchronize_end(); 962 963 // Does operations required after initialization has been done. 964 void post_initialize(); 965 966 // Initialize weak reference processing. 967 void ref_processing_init(); 968 969 virtual Name kind() const { 970 return CollectedHeap::G1; 971 } 972 973 virtual const char* name() const { 974 return "G1"; 975 } 976 977 const G1CollectorState* collector_state() const { return &_collector_state; } 978 G1CollectorState* collector_state() { return &_collector_state; } 979 980 // The current policy object for the collector. 981 G1Policy* policy() const { return _policy; } 982 // The remembered set. 983 G1RemSet* rem_set() const { return _rem_set; } 984 985 inline G1GCPhaseTimes* phase_times() const; 986 987 HeapRegionManager* hrm() const { return _hrm; } 988 989 const G1CollectionSet* collection_set() const { return &_collection_set; } 990 G1CollectionSet* collection_set() { return &_collection_set; } 991 992 virtual SoftRefPolicy* soft_ref_policy(); 993 994 virtual void initialize_serviceability(); 995 virtual MemoryUsage memory_usage(); 996 virtual GrowableArray<GCMemoryManager*> memory_managers(); 997 virtual GrowableArray<MemoryPool*> memory_pools(); 998 999 // Try to minimize the remembered set. 1000 void scrub_rem_set(); 1001 1002 // Apply the given closure on all cards in the Hot Card Cache, emptying it. 1003 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id); 1004 1005 // The shared block offset table array. 1006 G1BlockOffsetTable* bot() const { return _bot; } 1007 1008 // Reference Processing accessors 1009 1010 // The STW reference processor.... 1011 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 1012 1013 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; } 1014 1015 // The Concurrent Marking reference processor... 1016 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 1017 1018 size_t unused_committed_regions_in_bytes() const; 1019 1020 virtual size_t capacity() const; 1021 virtual size_t used() const; 1022 // This should be called when we're not holding the heap lock. The 1023 // result might be a bit inaccurate. 1024 size_t used_unlocked() const; 1025 size_t recalculate_used() const; 1026 1027 // These virtual functions do the actual allocation. 1028 // Some heaps may offer a contiguous region for shared non-blocking 1029 // allocation, via inlined code (by exporting the address of the top and 1030 // end fields defining the extent of the contiguous allocation region.) 1031 // But G1CollectedHeap doesn't yet support this. 1032 1033 virtual bool is_maximal_no_gc() const { 1034 return _hrm->available() == 0; 1035 } 1036 1037 // Returns whether there are any regions left in the heap for allocation. 1038 bool has_regions_left_for_allocation() const { 1039 return !is_maximal_no_gc() || num_free_regions() != 0; 1040 } 1041 1042 // The current number of regions in the heap. 1043 uint num_regions() const { return _hrm->length(); } 1044 1045 // The max number of regions in the heap. 1046 uint max_regions() const { return _hrm->max_length(); } 1047 1048 // Max number of regions that can be comitted. 1049 uint max_expandable_regions() const { return _hrm->max_expandable_length(); } 1050 1051 // The number of regions that are completely free. 1052 uint num_free_regions() const { return _hrm->num_free_regions(); } 1053 1054 // The number of regions that can be allocated into. 1055 uint num_free_or_available_regions() const { return num_free_regions() + _hrm->available(); } 1056 1057 MemoryUsage get_auxiliary_data_memory_usage() const { 1058 return _hrm->get_auxiliary_data_memory_usage(); 1059 } 1060 1061 // The number of regions that are not completely free. 1062 uint num_used_regions() const { return num_regions() - num_free_regions(); } 1063 1064 #ifdef ASSERT 1065 bool is_on_master_free_list(HeapRegion* hr) { 1066 return _hrm->is_free(hr); 1067 } 1068 #endif // ASSERT 1069 1070 inline void old_set_add(HeapRegion* hr); 1071 inline void old_set_remove(HeapRegion* hr); 1072 1073 inline void archive_set_add(HeapRegion* hr); 1074 1075 size_t non_young_capacity_bytes() { 1076 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes; 1077 } 1078 1079 // Determine whether the given region is one that we are using as an 1080 // old GC alloc region. 1081 bool is_old_gc_alloc_region(HeapRegion* hr); 1082 1083 // Perform a collection of the heap; intended for use in implementing 1084 // "System.gc". This probably implies as full a collection as the 1085 // "CollectedHeap" supports. 1086 virtual void collect(GCCause::Cause cause); 1087 1088 // Perform a collection of the heap with the given cause; if the VM operation 1089 // fails to execute for any reason, retry only if retry_on_gc_failure is set. 1090 // Returns whether this collection actually executed. 1091 bool try_collect(GCCause::Cause cause, bool retry_on_gc_failure); 1092 1093 // True iff an evacuation has failed in the most-recent collection. 1094 bool evacuation_failed() { return _evacuation_failed; } 1095 1096 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed); 1097 void prepend_to_freelist(FreeRegionList* list); 1098 void decrement_summary_bytes(size_t bytes); 1099 1100 virtual bool is_in(const void* p) const; 1101 #ifdef ASSERT 1102 // Returns whether p is in one of the available areas of the heap. Slow but 1103 // extensive version. 1104 bool is_in_exact(const void* p) const; 1105 #endif 1106 1107 // Return "TRUE" iff the given object address is within the collection 1108 // set. Assumes that the reference points into the heap. 1109 inline bool is_in_cset(const HeapRegion *hr); 1110 inline bool is_in_cset(oop obj); 1111 inline bool is_in_cset(HeapWord* addr); 1112 1113 inline bool is_in_cset_or_humongous(const oop obj); 1114 1115 private: 1116 // This array is used for a quick test on whether a reference points into 1117 // the collection set or not. Each of the array's elements denotes whether the 1118 // corresponding region is in the collection set or not. 1119 G1HeapRegionAttrBiasedMappedArray _region_attr; 1120 1121 public: 1122 1123 inline G1HeapRegionAttr region_attr(const void* obj) const; 1124 inline G1HeapRegionAttr region_attr(uint idx) const; 1125 1126 // Return "TRUE" iff the given object address is in the reserved 1127 // region of g1. 1128 bool is_in_g1_reserved(const void* p) const { 1129 return _hrm->reserved().contains(p); 1130 } 1131 1132 // Returns a MemRegion that corresponds to the space that has been 1133 // reserved for the heap 1134 MemRegion g1_reserved() const { 1135 return _hrm->reserved(); 1136 } 1137 1138 MemRegion reserved_region() const { 1139 return _reserved; 1140 } 1141 1142 HeapWord* base() const { 1143 return _reserved.start(); 1144 } 1145 1146 bool is_in_reserved(const void* addr) const { 1147 return _reserved.contains(addr); 1148 } 1149 1150 G1HotCardCache* g1_hot_card_cache() const { return _hot_card_cache; } 1151 1152 G1CardTable* card_table() const { 1153 return _card_table; 1154 } 1155 1156 // Iteration functions. 1157 1158 // Iterate over all objects, calling "cl.do_object" on each. 1159 virtual void object_iterate(ObjectClosure* cl); 1160 1161 virtual void safe_object_iterate(ObjectClosure* cl) { 1162 object_iterate(cl); 1163 } 1164 1165 // Iterate over heap regions, in address order, terminating the 1166 // iteration early if the "do_heap_region" method returns "true". 1167 void heap_region_iterate(HeapRegionClosure* blk) const; 1168 1169 // Return the region with the given index. It assumes the index is valid. 1170 inline HeapRegion* region_at(uint index) const; 1171 inline HeapRegion* region_at_or_null(uint index) const; 1172 1173 // Return the next region (by index) that is part of the same 1174 // humongous object that hr is part of. 1175 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const; 1176 1177 // Calculate the region index of the given address. Given address must be 1178 // within the heap. 1179 inline uint addr_to_region(HeapWord* addr) const; 1180 1181 inline HeapWord* bottom_addr_for_region(uint index) const; 1182 1183 // Two functions to iterate over the heap regions in parallel. Threads 1184 // compete using the HeapRegionClaimer to claim the regions before 1185 // applying the closure on them. 1186 // The _from_worker_offset version uses the HeapRegionClaimer and 1187 // the worker id to calculate a start offset to prevent all workers to 1188 // start from the point. 1189 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl, 1190 HeapRegionClaimer* hrclaimer, 1191 uint worker_id) const; 1192 1193 void heap_region_par_iterate_from_start(HeapRegionClosure* cl, 1194 HeapRegionClaimer* hrclaimer) const; 1195 1196 // Iterate over all regions currently in the current collection set. 1197 void collection_set_iterate_all(HeapRegionClosure* blk); 1198 1199 // Iterate over the regions in the current increment of the collection set. 1200 // Starts the iteration so that the start regions of a given worker id over the 1201 // set active_workers are evenly spread across the set of collection set regions 1202 // to be iterated. 1203 // The variant with the HeapRegionClaimer guarantees that the closure will be 1204 // applied to a particular region exactly once. 1205 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) { 1206 collection_set_iterate_increment_from(blk, NULL, worker_id); 1207 } 1208 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id); 1209 1210 // Returns the HeapRegion that contains addr. addr must not be NULL. 1211 template <class T> 1212 inline HeapRegion* heap_region_containing(const T addr) const; 1213 1214 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted 1215 // region. addr must not be NULL. 1216 template <class T> 1217 inline HeapRegion* heap_region_containing_or_null(const T addr) const; 1218 1219 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1220 // each address in the (reserved) heap is a member of exactly 1221 // one block. The defining characteristic of a block is that it is 1222 // possible to find its size, and thus to progress forward to the next 1223 // block. (Blocks may be of different sizes.) Thus, blocks may 1224 // represent Java objects, or they might be free blocks in a 1225 // free-list-based heap (or subheap), as long as the two kinds are 1226 // distinguishable and the size of each is determinable. 1227 1228 // Returns the address of the start of the "block" that contains the 1229 // address "addr". We say "blocks" instead of "object" since some heaps 1230 // may not pack objects densely; a chunk may either be an object or a 1231 // non-object. 1232 HeapWord* block_start(const void* addr) const; 1233 1234 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1235 // the block is an object. 1236 bool block_is_obj(const HeapWord* addr) const; 1237 1238 // Section on thread-local allocation buffers (TLABs) 1239 // See CollectedHeap for semantics. 1240 1241 bool supports_tlab_allocation() const; 1242 size_t tlab_capacity(Thread* ignored) const; 1243 size_t tlab_used(Thread* ignored) const; 1244 size_t max_tlab_size() const; 1245 size_t unsafe_max_tlab_alloc(Thread* ignored) const; 1246 1247 inline bool is_in_young(const oop obj); 1248 1249 // Returns "true" iff the given word_size is "very large". 1250 static bool is_humongous(size_t word_size) { 1251 // Note this has to be strictly greater-than as the TLABs 1252 // are capped at the humongous threshold and we want to 1253 // ensure that we don't try to allocate a TLAB as 1254 // humongous and that we don't allocate a humongous 1255 // object in a TLAB. 1256 return word_size > _humongous_object_threshold_in_words; 1257 } 1258 1259 // Returns the humongous threshold for a specific region size 1260 static size_t humongous_threshold_for(size_t region_size) { 1261 return (region_size / 2); 1262 } 1263 1264 // Returns the number of regions the humongous object of the given word size 1265 // requires. 1266 static size_t humongous_obj_size_in_regions(size_t word_size); 1267 1268 // Print the maximum heap capacity. 1269 virtual size_t max_capacity() const; 1270 1271 // Return the size of reserved memory. Returns different value than max_capacity() when AllocateOldGenAt is used. 1272 virtual size_t max_reserved_capacity() const; 1273 1274 virtual jlong millis_since_last_gc(); 1275 1276 1277 // Convenience function to be used in situations where the heap type can be 1278 // asserted to be this type. 1279 static G1CollectedHeap* heap(); 1280 1281 void set_region_short_lived_locked(HeapRegion* hr); 1282 // add appropriate methods for any other surv rate groups 1283 1284 const G1SurvivorRegions* survivor() const { return &_survivor; } 1285 1286 uint eden_regions_count() const { return _eden.length(); } 1287 uint survivor_regions_count() const { return _survivor.length(); } 1288 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); } 1289 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); } 1290 uint young_regions_count() const { return _eden.length() + _survivor.length(); } 1291 uint old_regions_count() const { return _old_set.length(); } 1292 uint archive_regions_count() const { return _archive_set.length(); } 1293 uint humongous_regions_count() const { return _humongous_set.length(); } 1294 1295 #ifdef ASSERT 1296 bool check_young_list_empty(); 1297 #endif 1298 1299 // *** Stuff related to concurrent marking. It's not clear to me that so 1300 // many of these need to be public. 1301 1302 // The functions below are helper functions that a subclass of 1303 // "CollectedHeap" can use in the implementation of its virtual 1304 // functions. 1305 // This performs a concurrent marking of the live objects in a 1306 // bitmap off to the side. 1307 void do_concurrent_mark(); 1308 1309 bool is_marked_next(oop obj) const; 1310 1311 // Determine if an object is dead, given the object and also 1312 // the region to which the object belongs. An object is dead 1313 // iff a) it was not allocated since the last mark, b) it 1314 // is not marked, and c) it is not in an archive region. 1315 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1316 return 1317 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) && 1318 !hr->is_archive(); 1319 } 1320 1321 // This function returns true when an object has been 1322 // around since the previous marking and hasn't yet 1323 // been marked during this marking, and is not in an archive region. 1324 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1325 return 1326 !hr->obj_allocated_since_next_marking(obj) && 1327 !is_marked_next(obj) && 1328 !hr->is_archive(); 1329 } 1330 1331 // Determine if an object is dead, given only the object itself. 1332 // This will find the region to which the object belongs and 1333 // then call the region version of the same function. 1334 1335 // Added if it is NULL it isn't dead. 1336 1337 inline bool is_obj_dead(const oop obj) const; 1338 1339 inline bool is_obj_ill(const oop obj) const; 1340 1341 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const; 1342 inline bool is_obj_dead_full(const oop obj) const; 1343 1344 G1ConcurrentMark* concurrent_mark() const { return _cm; } 1345 1346 // Refinement 1347 1348 G1ConcurrentRefine* concurrent_refine() const { return _cr; } 1349 1350 // Optimized nmethod scanning support routines 1351 1352 // Register the given nmethod with the G1 heap. 1353 virtual void register_nmethod(nmethod* nm); 1354 1355 // Unregister the given nmethod from the G1 heap. 1356 virtual void unregister_nmethod(nmethod* nm); 1357 1358 // No nmethod flushing needed. 1359 virtual void flush_nmethod(nmethod* nm) {} 1360 1361 // No nmethod verification implemented. 1362 virtual void verify_nmethod(nmethod* nm) {} 1363 1364 // Free up superfluous code root memory. 1365 void purge_code_root_memory(); 1366 1367 // Rebuild the strong code root lists for each region 1368 // after a full GC. 1369 void rebuild_strong_code_roots(); 1370 1371 // Partial cleaning of VM internal data structures. 1372 void string_dedup_cleaning(BoolObjectClosure* is_alive, 1373 OopClosure* keep_alive, 1374 G1GCPhaseTimes* phase_times = NULL); 1375 1376 // Performs cleaning of data structures after class unloading. 1377 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred); 1378 1379 // Redirty logged cards in the refinement queue. 1380 void redirty_logged_cards(G1RedirtyCardsQueueSet* rdcqs); 1381 1382 // Verification 1383 1384 // Deduplicate the string 1385 virtual void deduplicate_string(oop str); 1386 1387 // Perform any cleanup actions necessary before allowing a verification. 1388 virtual void prepare_for_verify(); 1389 1390 // Perform verification. 1391 1392 // vo == UsePrevMarking -> use "prev" marking information, 1393 // vo == UseNextMarking -> use "next" marking information 1394 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS 1395 // 1396 // NOTE: Only the "prev" marking information is guaranteed to be 1397 // consistent most of the time, so most calls to this should use 1398 // vo == UsePrevMarking. 1399 // Currently, there is only one case where this is called with 1400 // vo == UseNextMarking, which is to verify the "next" marking 1401 // information at the end of remark. 1402 // Currently there is only one place where this is called with 1403 // vo == UseFullMarking, which is to verify the marking during a 1404 // full GC. 1405 void verify(VerifyOption vo); 1406 1407 // WhiteBox testing support. 1408 virtual bool supports_concurrent_phase_control() const; 1409 virtual bool request_concurrent_phase(const char* phase); 1410 bool is_heterogeneous_heap() const; 1411 1412 virtual WorkGang* get_safepoint_workers() { return _workers; } 1413 1414 // The methods below are here for convenience and dispatch the 1415 // appropriate method depending on value of the given VerifyOption 1416 // parameter. The values for that parameter, and their meanings, 1417 // are the same as those above. 1418 1419 bool is_obj_dead_cond(const oop obj, 1420 const HeapRegion* hr, 1421 const VerifyOption vo) const; 1422 1423 bool is_obj_dead_cond(const oop obj, 1424 const VerifyOption vo) const; 1425 1426 G1HeapSummary create_g1_heap_summary(); 1427 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats); 1428 1429 // Printing 1430 private: 1431 void print_heap_regions() const; 1432 void print_regions_on(outputStream* st) const; 1433 1434 public: 1435 virtual void print_on(outputStream* st) const; 1436 virtual void print_extended_on(outputStream* st) const; 1437 virtual void print_on_error(outputStream* st) const; 1438 1439 virtual void print_gc_threads_on(outputStream* st) const; 1440 virtual void gc_threads_do(ThreadClosure* tc) const; 1441 1442 // Override 1443 void print_tracing_info() const; 1444 1445 // The following two methods are helpful for debugging RSet issues. 1446 void print_cset_rsets() PRODUCT_RETURN; 1447 void print_all_rsets() PRODUCT_RETURN; 1448 1449 // Used to print information about locations in the hs_err file. 1450 virtual bool print_location(outputStream* st, void* addr) const; 1451 1452 size_t pending_card_num(); 1453 }; 1454 1455 class G1ParEvacuateFollowersClosure : public VoidClosure { 1456 private: 1457 double _start_term; 1458 double _term_time; 1459 size_t _term_attempts; 1460 1461 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); } 1462 void end_term_time() { _term_time += (os::elapsedTime() - _start_term); } 1463 protected: 1464 G1CollectedHeap* _g1h; 1465 G1ParScanThreadState* _par_scan_state; 1466 RefToScanQueueSet* _queues; 1467 ParallelTaskTerminator* _terminator; 1468 G1GCPhaseTimes::GCParPhases _phase; 1469 1470 G1ParScanThreadState* par_scan_state() { return _par_scan_state; } 1471 RefToScanQueueSet* queues() { return _queues; } 1472 ParallelTaskTerminator* terminator() { return _terminator; } 1473 1474 public: 1475 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h, 1476 G1ParScanThreadState* par_scan_state, 1477 RefToScanQueueSet* queues, 1478 ParallelTaskTerminator* terminator, 1479 G1GCPhaseTimes::GCParPhases phase) 1480 : _start_term(0.0), _term_time(0.0), _term_attempts(0), 1481 _g1h(g1h), _par_scan_state(par_scan_state), 1482 _queues(queues), _terminator(terminator), _phase(phase) {} 1483 1484 void do_void(); 1485 1486 double term_time() const { return _term_time; } 1487 size_t term_attempts() const { return _term_attempts; } 1488 1489 private: 1490 inline bool offer_termination(); 1491 }; 1492 1493 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP