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/g1NUMA.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 VM_CollectForMetadataAllocation; 134 friend class VM_G1CollectForAllocation; 135 friend class VM_G1CollectFull; 136 friend class VM_G1TryInitiateConcMark; 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 // Handle G1 NUMA support. 197 G1NUMA* _numa; 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 // Return true if an explicit GC should start a concurrent cycle instead 264 // of doing a STW full GC. A concurrent cycle should be started if: 265 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, 266 // (b) cause == _g1_humongous_allocation, 267 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent, 268 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent, 269 // (e) cause == _wb_conc_mark, 270 // (f) cause == _g1_periodic_collection and +G1PeriodicGCInvokesConcurrent. 271 bool should_do_concurrent_full_gc(GCCause::Cause cause); 272 273 // Attempt to start a concurrent cycle with the indicated cause. 274 // precondition: should_do_concurrent_full_gc(cause) 275 bool try_collect_concurrently(GCCause::Cause cause, 276 uint gc_counter, 277 uint old_marking_started_before); 278 279 // Return true if should upgrade to full gc after an incremental one. 280 bool should_upgrade_to_full_gc(GCCause::Cause cause); 281 282 // indicates whether we are in young or mixed GC mode 283 G1CollectorState _collector_state; 284 285 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 286 // concurrent cycles) we have started. 287 volatile uint _old_marking_cycles_started; 288 289 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 290 // concurrent cycles) we have completed. 291 volatile uint _old_marking_cycles_completed; 292 293 // This is a non-product method that is helpful for testing. It is 294 // called at the end of a GC and artificially expands the heap by 295 // allocating a number of dead regions. This way we can induce very 296 // frequent marking cycles and stress the cleanup / concurrent 297 // cleanup code more (as all the regions that will be allocated by 298 // this method will be found dead by the marking cycle). 299 void allocate_dummy_regions() PRODUCT_RETURN; 300 301 // If the HR printer is active, dump the state of the regions in the 302 // heap after a compaction. 303 void print_hrm_post_compaction(); 304 305 // Create a memory mapper for auxiliary data structures of the given size and 306 // translation factor. 307 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description, 308 size_t size, 309 size_t translation_factor); 310 311 void trace_heap(GCWhen::Type when, const GCTracer* tracer); 312 313 // These are macros so that, if the assert fires, we get the correct 314 // line number, file, etc. 315 316 #define heap_locking_asserts_params(_extra_message_) \ 317 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 318 (_extra_message_), \ 319 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 320 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 321 BOOL_TO_STR(Thread::current()->is_VM_thread()) 322 323 #define assert_heap_locked() \ 324 do { \ 325 assert(Heap_lock->owned_by_self(), \ 326 heap_locking_asserts_params("should be holding the Heap_lock")); \ 327 } while (0) 328 329 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 330 do { \ 331 assert(Heap_lock->owned_by_self() || \ 332 (SafepointSynchronize::is_at_safepoint() && \ 333 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 334 heap_locking_asserts_params("should be holding the Heap_lock or " \ 335 "should be at a safepoint")); \ 336 } while (0) 337 338 #define assert_heap_locked_and_not_at_safepoint() \ 339 do { \ 340 assert(Heap_lock->owned_by_self() && \ 341 !SafepointSynchronize::is_at_safepoint(), \ 342 heap_locking_asserts_params("should be holding the Heap_lock and " \ 343 "should not be at a safepoint")); \ 344 } while (0) 345 346 #define assert_heap_not_locked() \ 347 do { \ 348 assert(!Heap_lock->owned_by_self(), \ 349 heap_locking_asserts_params("should not be holding the Heap_lock")); \ 350 } while (0) 351 352 #define assert_heap_not_locked_and_not_at_safepoint() \ 353 do { \ 354 assert(!Heap_lock->owned_by_self() && \ 355 !SafepointSynchronize::is_at_safepoint(), \ 356 heap_locking_asserts_params("should not be holding the Heap_lock and " \ 357 "should not be at a safepoint")); \ 358 } while (0) 359 360 #define assert_at_safepoint_on_vm_thread() \ 361 do { \ 362 assert_at_safepoint(); \ 363 assert(Thread::current_or_null() != NULL, "no current thread"); \ 364 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \ 365 } while (0) 366 367 #ifdef ASSERT 368 #define assert_used_and_recalculate_used_equal(g1h) \ 369 do { \ 370 size_t cur_used_bytes = g1h->used(); \ 371 size_t recal_used_bytes = g1h->recalculate_used(); \ 372 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \ 373 " same as recalculated used(" SIZE_FORMAT ").", \ 374 cur_used_bytes, recal_used_bytes); \ 375 } while (0) 376 #else 377 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0) 378 #endif 379 380 const char* young_gc_name() const; 381 382 // The young region list. 383 G1EdenRegions _eden; 384 G1SurvivorRegions _survivor; 385 386 STWGCTimer* _gc_timer_stw; 387 388 G1NewTracer* _gc_tracer_stw; 389 390 // The current policy object for the collector. 391 G1Policy* _policy; 392 G1HeapSizingPolicy* _heap_sizing_policy; 393 394 G1CollectionSet _collection_set; 395 396 // Try to allocate a single non-humongous HeapRegion sufficient for 397 // an allocation of the given word_size. If do_expand is true, 398 // attempt to expand the heap if necessary to satisfy the allocation 399 // request. 'type' takes the type of region to be allocated. (Use constants 400 // Old, Eden, Humongous, Survivor defined in HeapRegionType.) 401 HeapRegion* new_region(size_t word_size, 402 HeapRegionType type, 403 bool do_expand, 404 uint node_index = G1NUMA::AnyNodeIndex); 405 406 // Initialize a contiguous set of free regions of length num_regions 407 // and starting at index first so that they appear as a single 408 // humongous region. 409 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 410 uint num_regions, 411 size_t word_size); 412 413 // Attempt to allocate a humongous object of the given size. Return 414 // NULL if unsuccessful. 415 HeapWord* humongous_obj_allocate(size_t word_size); 416 417 // The following two methods, allocate_new_tlab() and 418 // mem_allocate(), are the two main entry points from the runtime 419 // into the G1's allocation routines. They have the following 420 // assumptions: 421 // 422 // * They should both be called outside safepoints. 423 // 424 // * They should both be called without holding the Heap_lock. 425 // 426 // * All allocation requests for new TLABs should go to 427 // allocate_new_tlab(). 428 // 429 // * All non-TLAB allocation requests should go to mem_allocate(). 430 // 431 // * If either call cannot satisfy the allocation request using the 432 // current allocating region, they will try to get a new one. If 433 // this fails, they will attempt to do an evacuation pause and 434 // retry the allocation. 435 // 436 // * If all allocation attempts fail, even after trying to schedule 437 // an evacuation pause, allocate_new_tlab() will return NULL, 438 // whereas mem_allocate() will attempt a heap expansion and/or 439 // schedule a Full GC. 440 // 441 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 442 // should never be called with word_size being humongous. All 443 // humongous allocation requests should go to mem_allocate() which 444 // will satisfy them with a special path. 445 446 virtual HeapWord* allocate_new_tlab(size_t min_size, 447 size_t requested_size, 448 size_t* actual_size); 449 450 virtual HeapWord* mem_allocate(size_t word_size, 451 bool* gc_overhead_limit_was_exceeded); 452 453 // First-level mutator allocation attempt: try to allocate out of 454 // the mutator alloc region without taking the Heap_lock. This 455 // should only be used for non-humongous allocations. 456 inline HeapWord* attempt_allocation(size_t min_word_size, 457 size_t desired_word_size, 458 size_t* actual_word_size); 459 460 // Second-level mutator allocation attempt: take the Heap_lock and 461 // retry the allocation attempt, potentially scheduling a GC 462 // pause. This should only be used for non-humongous allocations. 463 HeapWord* attempt_allocation_slow(size_t word_size); 464 465 // Takes the Heap_lock and attempts a humongous allocation. It can 466 // potentially schedule a GC pause. 467 HeapWord* attempt_allocation_humongous(size_t word_size); 468 469 // Allocation attempt that should be called during safepoints (e.g., 470 // at the end of a successful GC). expect_null_mutator_alloc_region 471 // specifies whether the mutator alloc region is expected to be NULL 472 // or not. 473 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 474 bool expect_null_mutator_alloc_region); 475 476 // These methods are the "callbacks" from the G1AllocRegion class. 477 478 // For mutator alloc regions. 479 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index); 480 void retire_mutator_alloc_region(HeapRegion* alloc_region, 481 size_t allocated_bytes); 482 483 // For GC alloc regions. 484 bool has_more_regions(G1HeapRegionAttr dest); 485 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index); 486 void retire_gc_alloc_region(HeapRegion* alloc_region, 487 size_t allocated_bytes, G1HeapRegionAttr dest); 488 489 // - if explicit_gc is true, the GC is for a System.gc() etc, 490 // otherwise it's for a failed allocation. 491 // - if clear_all_soft_refs is true, all soft references should be 492 // cleared during the GC. 493 // - it returns false if it is unable to do the collection due to the 494 // GC locker being active, true otherwise. 495 bool do_full_collection(bool explicit_gc, 496 bool clear_all_soft_refs); 497 498 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread. 499 virtual void do_full_collection(bool clear_all_soft_refs); 500 501 // Callback from VM_G1CollectForAllocation operation. 502 // This function does everything necessary/possible to satisfy a 503 // failed allocation request (including collection, expansion, etc.) 504 HeapWord* satisfy_failed_allocation(size_t word_size, 505 bool* succeeded); 506 // Internal helpers used during full GC to split it up to 507 // increase readability. 508 void abort_concurrent_cycle(); 509 void verify_before_full_collection(bool explicit_gc); 510 void prepare_heap_for_full_collection(); 511 void prepare_heap_for_mutators(); 512 void abort_refinement(); 513 void verify_after_full_collection(); 514 void print_heap_after_full_collection(G1HeapTransition* heap_transition); 515 516 // Helper method for satisfy_failed_allocation() 517 HeapWord* satisfy_failed_allocation_helper(size_t word_size, 518 bool do_gc, 519 bool clear_all_soft_refs, 520 bool expect_null_mutator_alloc_region, 521 bool* gc_succeeded); 522 523 // Attempting to expand the heap sufficiently 524 // to support an allocation of the given "word_size". If 525 // successful, perform the allocation and return the address of the 526 // allocated block, or else "NULL". 527 HeapWord* expand_and_allocate(size_t word_size); 528 529 // Process any reference objects discovered. 530 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states); 531 532 // If during an initial mark pause we may install a pending list head which is not 533 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking 534 // to discover. 535 void make_pending_list_reachable(); 536 537 // Merges the information gathered on a per-thread basis for all worker threads 538 // during GC into global variables. 539 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states); 540 541 void verify_numa_regions(const char* desc); 542 543 public: 544 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; } 545 546 WorkGang* workers() const { return _workers; } 547 548 // Runs the given AbstractGangTask with the current active workers, returning the 549 // total time taken. 550 Tickspan run_task(AbstractGangTask* task); 551 552 G1Allocator* allocator() { 553 return _allocator; 554 } 555 556 G1HeapVerifier* verifier() { 557 return _verifier; 558 } 559 560 G1MonitoringSupport* g1mm() { 561 assert(_g1mm != NULL, "should have been initialized"); 562 return _g1mm; 563 } 564 565 void resize_heap_if_necessary(); 566 567 G1NUMA* numa() const { return _numa; } 568 569 // Expand the garbage-first heap by at least the given size (in bytes!). 570 // Returns true if the heap was expanded by the requested amount; 571 // false otherwise. 572 // (Rounds up to a HeapRegion boundary.) 573 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL); 574 bool expand_single_region(uint node_index); 575 576 // Returns the PLAB statistics for a given destination. 577 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest); 578 579 // Determines PLAB size for a given destination. 580 inline size_t desired_plab_sz(G1HeapRegionAttr dest); 581 582 // Do anything common to GC's. 583 void gc_prologue(bool full); 584 void gc_epilogue(bool full); 585 586 // Does the given region fulfill remembered set based eager reclaim candidate requirements? 587 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const; 588 589 // Modify the reclaim candidate set and test for presence. 590 // These are only valid for starts_humongous regions. 591 inline void set_humongous_reclaim_candidate(uint region, bool value); 592 inline bool is_humongous_reclaim_candidate(uint region); 593 594 // Remove from the reclaim candidate set. Also remove from the 595 // collection set so that later encounters avoid the slow path. 596 inline void set_humongous_is_live(oop obj); 597 598 // Register the given region to be part of the collection set. 599 inline void register_humongous_region_with_region_attr(uint index); 600 // Update region attributes table with information about all regions. 601 void register_regions_with_region_attr(); 602 // We register a region with the fast "in collection set" test. We 603 // simply set to true the array slot corresponding to this region. 604 void register_young_region_with_region_attr(HeapRegion* r) { 605 _region_attr.set_in_young(r->hrm_index()); 606 } 607 inline void register_region_with_region_attr(HeapRegion* r); 608 inline void register_old_region_with_region_attr(HeapRegion* r); 609 inline void register_optional_region_with_region_attr(HeapRegion* r); 610 611 void clear_region_attr(const HeapRegion* hr) { 612 _region_attr.clear(hr); 613 } 614 615 void clear_region_attr() { 616 _region_attr.clear(); 617 } 618 619 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking 620 // for all regions. 621 void verify_region_attr_remset_update() PRODUCT_RETURN; 622 623 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause); 624 625 // This is called at the start of either a concurrent cycle or a Full 626 // GC to update the number of old marking cycles started. 627 void increment_old_marking_cycles_started(); 628 629 // This is called at the end of either a concurrent cycle or a Full 630 // GC to update the number of old marking cycles completed. Those two 631 // can happen in a nested fashion, i.e., we start a concurrent 632 // cycle, a Full GC happens half-way through it which ends first, 633 // and then the cycle notices that a Full GC happened and ends 634 // too. The concurrent parameter is a boolean to help us do a bit 635 // tighter consistency checking in the method. If concurrent is 636 // false, the caller is the inner caller in the nesting (i.e., the 637 // Full GC). If concurrent is true, the caller is the outer caller 638 // in this nesting (i.e., the concurrent cycle). Further nesting is 639 // not currently supported. The end of this call also notifies 640 // the G1OldGCCount_lock in case a Java thread is waiting for a full 641 // GC to happen (e.g., it called System.gc() with 642 // +ExplicitGCInvokesConcurrent). 643 void increment_old_marking_cycles_completed(bool concurrent); 644 645 uint old_marking_cycles_completed() { 646 return _old_marking_cycles_completed; 647 } 648 649 G1HRPrinter* hr_printer() { return &_hr_printer; } 650 651 // Allocates a new heap region instance. 652 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr); 653 654 // Allocate the highest free region in the reserved heap. This will commit 655 // regions as necessary. 656 HeapRegion* alloc_highest_free_region(); 657 658 // Frees a non-humongous region by initializing its contents and 659 // adding it to the free list that's passed as a parameter (this is 660 // usually a local list which will be appended to the master free 661 // list later). The used bytes of freed regions are accumulated in 662 // pre_used. If skip_remset is true, the region's RSet will not be freed 663 // up. If skip_hot_card_cache is true, the region's hot card cache will not 664 // be freed up. The assumption is that this will be done later. 665 // The locked parameter indicates if the caller has already taken 666 // care of proper synchronization. This may allow some optimizations. 667 void free_region(HeapRegion* hr, 668 FreeRegionList* free_list, 669 bool skip_remset, 670 bool skip_hot_card_cache = false, 671 bool locked = false); 672 673 // It dirties the cards that cover the block so that the post 674 // write barrier never queues anything when updating objects on this 675 // block. It is assumed (and in fact we assert) that the block 676 // belongs to a young region. 677 inline void dirty_young_block(HeapWord* start, size_t word_size); 678 679 // Frees a humongous region by collapsing it into individual regions 680 // and calling free_region() for each of them. The freed regions 681 // will be added to the free list that's passed as a parameter (this 682 // is usually a local list which will be appended to the master free 683 // list later). 684 // The method assumes that only a single thread is ever calling 685 // this for a particular region at once. 686 void free_humongous_region(HeapRegion* hr, 687 FreeRegionList* free_list); 688 689 // Facility for allocating in 'archive' regions in high heap memory and 690 // recording the allocated ranges. These should all be called from the 691 // VM thread at safepoints, without the heap lock held. They can be used 692 // to create and archive a set of heap regions which can be mapped at the 693 // same fixed addresses in a subsequent JVM invocation. 694 void begin_archive_alloc_range(bool open = false); 695 696 // Check if the requested size would be too large for an archive allocation. 697 bool is_archive_alloc_too_large(size_t word_size); 698 699 // Allocate memory of the requested size from the archive region. This will 700 // return NULL if the size is too large or if no memory is available. It 701 // does not trigger a garbage collection. 702 HeapWord* archive_mem_allocate(size_t word_size); 703 704 // Optionally aligns the end address and returns the allocated ranges in 705 // an array of MemRegions in order of ascending addresses. 706 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges, 707 size_t end_alignment_in_bytes = 0); 708 709 // Facility for allocating a fixed range within the heap and marking 710 // the containing regions as 'archive'. For use at JVM init time, when the 711 // caller may mmap archived heap data at the specified range(s). 712 // Verify that the MemRegions specified in the argument array are within the 713 // reserved heap. 714 bool check_archive_addresses(MemRegion* range, size_t count); 715 716 // Commit the appropriate G1 regions containing the specified MemRegions 717 // and mark them as 'archive' regions. The regions in the array must be 718 // non-overlapping and in order of ascending address. 719 bool alloc_archive_regions(MemRegion* range, size_t count, bool open); 720 721 // Insert any required filler objects in the G1 regions around the specified 722 // ranges to make the regions parseable. This must be called after 723 // alloc_archive_regions, and after class loading has occurred. 724 void fill_archive_regions(MemRegion* range, size_t count); 725 726 // For each of the specified MemRegions, uncommit the containing G1 regions 727 // which had been allocated by alloc_archive_regions. This should be called 728 // rather than fill_archive_regions at JVM init time if the archive file 729 // mapping failed, with the same non-overlapping and sorted MemRegion array. 730 void dealloc_archive_regions(MemRegion* range, size_t count, bool is_open); 731 732 oop materialize_archived_object(oop obj); 733 734 private: 735 736 // Shrink the garbage-first heap by at most the given size (in bytes!). 737 // (Rounds down to a HeapRegion boundary.) 738 void shrink(size_t expand_bytes); 739 void shrink_helper(size_t expand_bytes); 740 741 #if TASKQUEUE_STATS 742 static void print_taskqueue_stats_hdr(outputStream* const st); 743 void print_taskqueue_stats() const; 744 void reset_taskqueue_stats(); 745 #endif // TASKQUEUE_STATS 746 747 // Schedule the VM operation that will do an evacuation pause to 748 // satisfy an allocation request of word_size. *succeeded will 749 // return whether the VM operation was successful (it did do an 750 // evacuation pause) or not (another thread beat us to it or the GC 751 // locker was active). Given that we should not be holding the 752 // Heap_lock when we enter this method, we will pass the 753 // gc_count_before (i.e., total_collections()) as a parameter since 754 // it has to be read while holding the Heap_lock. Currently, both 755 // methods that call do_collection_pause() release the Heap_lock 756 // before the call, so it's easy to read gc_count_before just before. 757 HeapWord* do_collection_pause(size_t word_size, 758 uint gc_count_before, 759 bool* succeeded, 760 GCCause::Cause gc_cause); 761 762 void wait_for_root_region_scanning(); 763 764 // The guts of the incremental collection pause, executed by the vm 765 // thread. It returns false if it is unable to do the collection due 766 // to the GC locker being active, true otherwise 767 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 768 769 G1HeapVerifier::G1VerifyType young_collection_verify_type() const; 770 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type); 771 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type); 772 773 void calculate_collection_set(G1EvacuationInfo& evacuation_info, double target_pause_time_ms); 774 775 // Actually do the work of evacuating the parts of the collection set. 776 void evacuate_initial_collection_set(G1ParScanThreadStateSet* per_thread_states); 777 void evacuate_optional_collection_set(G1ParScanThreadStateSet* per_thread_states); 778 private: 779 // Evacuate the next set of optional regions. 780 void evacuate_next_optional_regions(G1ParScanThreadStateSet* per_thread_states); 781 782 public: 783 void pre_evacuate_collection_set(G1EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss); 784 void post_evacuate_collection_set(G1EvacuationInfo& evacuation_info, 785 G1RedirtyCardsQueueSet* rdcqs, 786 G1ParScanThreadStateSet* pss); 787 788 void expand_heap_after_young_collection(); 789 // Update object copying statistics. 790 void record_obj_copy_mem_stats(); 791 792 // The hot card cache for remembered set insertion optimization. 793 G1HotCardCache* _hot_card_cache; 794 795 // The g1 remembered set of the heap. 796 G1RemSet* _rem_set; 797 798 // After a collection pause, convert the regions in the collection set into free 799 // regions. 800 void free_collection_set(G1CollectionSet* collection_set, G1EvacuationInfo& evacuation_info, const size_t* surviving_young_words); 801 802 // Abandon the current collection set without recording policy 803 // statistics or updating free lists. 804 void abandon_collection_set(G1CollectionSet* collection_set); 805 806 // The concurrent marker (and the thread it runs in.) 807 G1ConcurrentMark* _cm; 808 G1ConcurrentMarkThread* _cm_thread; 809 810 // The concurrent refiner. 811 G1ConcurrentRefine* _cr; 812 813 // The parallel task queues 814 RefToScanQueueSet *_task_queues; 815 816 // True iff a evacuation has failed in the current collection. 817 bool _evacuation_failed; 818 819 EvacuationFailedInfo* _evacuation_failed_info_array; 820 821 // Failed evacuations cause some logical from-space objects to have 822 // forwarding pointers to themselves. Reset them. 823 void remove_self_forwarding_pointers(G1RedirtyCardsQueueSet* rdcqs); 824 825 // Restore the objects in the regions in the collection set after an 826 // evacuation failure. 827 void restore_after_evac_failure(G1RedirtyCardsQueueSet* rdcqs); 828 829 PreservedMarksSet _preserved_marks_set; 830 831 // Preserve the mark of "obj", if necessary, in preparation for its mark 832 // word being overwritten with a self-forwarding-pointer. 833 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markWord m); 834 835 #ifndef PRODUCT 836 // Support for forcing evacuation failures. Analogous to 837 // PromotionFailureALot for the other collectors. 838 839 // Records whether G1EvacuationFailureALot should be in effect 840 // for the current GC 841 bool _evacuation_failure_alot_for_current_gc; 842 843 // Used to record the GC number for interval checking when 844 // determining whether G1EvaucationFailureALot is in effect 845 // for the current GC. 846 size_t _evacuation_failure_alot_gc_number; 847 848 // Count of the number of evacuations between failures. 849 volatile size_t _evacuation_failure_alot_count; 850 851 // Set whether G1EvacuationFailureALot should be in effect 852 // for the current GC (based upon the type of GC and which 853 // command line flags are set); 854 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc, 855 bool during_initial_mark, 856 bool mark_or_rebuild_in_progress); 857 858 inline void set_evacuation_failure_alot_for_current_gc(); 859 860 // Return true if it's time to cause an evacuation failure. 861 inline bool evacuation_should_fail(); 862 863 // Reset the G1EvacuationFailureALot counters. Should be called at 864 // the end of an evacuation pause in which an evacuation failure occurred. 865 inline void reset_evacuation_should_fail(); 866 #endif // !PRODUCT 867 868 // ("Weak") Reference processing support. 869 // 870 // G1 has 2 instances of the reference processor class. One 871 // (_ref_processor_cm) handles reference object discovery 872 // and subsequent processing during concurrent marking cycles. 873 // 874 // The other (_ref_processor_stw) handles reference object 875 // discovery and processing during full GCs and incremental 876 // evacuation pauses. 877 // 878 // During an incremental pause, reference discovery will be 879 // temporarily disabled for _ref_processor_cm and will be 880 // enabled for _ref_processor_stw. At the end of the evacuation 881 // pause references discovered by _ref_processor_stw will be 882 // processed and discovery will be disabled. The previous 883 // setting for reference object discovery for _ref_processor_cm 884 // will be re-instated. 885 // 886 // At the start of marking: 887 // * Discovery by the CM ref processor is verified to be inactive 888 // and it's discovered lists are empty. 889 // * Discovery by the CM ref processor is then enabled. 890 // 891 // At the end of marking: 892 // * Any references on the CM ref processor's discovered 893 // lists are processed (possibly MT). 894 // 895 // At the start of full GC we: 896 // * Disable discovery by the CM ref processor and 897 // empty CM ref processor's discovered lists 898 // (without processing any entries). 899 // * Verify that the STW ref processor is inactive and it's 900 // discovered lists are empty. 901 // * Temporarily set STW ref processor discovery as single threaded. 902 // * Temporarily clear the STW ref processor's _is_alive_non_header 903 // field. 904 // * Finally enable discovery by the STW ref processor. 905 // 906 // The STW ref processor is used to record any discovered 907 // references during the full GC. 908 // 909 // At the end of a full GC we: 910 // * Enqueue any reference objects discovered by the STW ref processor 911 // that have non-live referents. This has the side-effect of 912 // making the STW ref processor inactive by disabling discovery. 913 // * Verify that the CM ref processor is still inactive 914 // and no references have been placed on it's discovered 915 // lists (also checked as a precondition during initial marking). 916 917 // The (stw) reference processor... 918 ReferenceProcessor* _ref_processor_stw; 919 920 // During reference object discovery, the _is_alive_non_header 921 // closure (if non-null) is applied to the referent object to 922 // determine whether the referent is live. If so then the 923 // reference object does not need to be 'discovered' and can 924 // be treated as a regular oop. This has the benefit of reducing 925 // the number of 'discovered' reference objects that need to 926 // be processed. 927 // 928 // Instance of the is_alive closure for embedding into the 929 // STW reference processor as the _is_alive_non_header field. 930 // Supplying a value for the _is_alive_non_header field is 931 // optional but doing so prevents unnecessary additions to 932 // the discovered lists during reference discovery. 933 G1STWIsAliveClosure _is_alive_closure_stw; 934 935 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw; 936 937 // The (concurrent marking) reference processor... 938 ReferenceProcessor* _ref_processor_cm; 939 940 // Instance of the concurrent mark is_alive closure for embedding 941 // into the Concurrent Marking reference processor as the 942 // _is_alive_non_header field. Supplying a value for the 943 // _is_alive_non_header field is optional but doing so prevents 944 // unnecessary additions to the discovered lists during reference 945 // discovery. 946 G1CMIsAliveClosure _is_alive_closure_cm; 947 948 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm; 949 public: 950 951 RefToScanQueue *task_queue(uint i) const; 952 953 uint num_task_queues() const; 954 955 // Create a G1CollectedHeap. 956 // Must call the initialize method afterwards. 957 // May not return if something goes wrong. 958 G1CollectedHeap(); 959 960 private: 961 jint initialize_concurrent_refinement(); 962 jint initialize_young_gen_sampling_thread(); 963 public: 964 // Initialize the G1CollectedHeap to have the initial and 965 // maximum sizes and remembered and barrier sets 966 // specified by the policy object. 967 jint initialize(); 968 969 virtual void stop(); 970 virtual void safepoint_synchronize_begin(); 971 virtual void safepoint_synchronize_end(); 972 973 // Does operations required after initialization has been done. 974 void post_initialize(); 975 976 // Initialize weak reference processing. 977 void ref_processing_init(); 978 979 virtual Name kind() const { 980 return CollectedHeap::G1; 981 } 982 983 virtual const char* name() const { 984 return "G1"; 985 } 986 987 const G1CollectorState* collector_state() const { return &_collector_state; } 988 G1CollectorState* collector_state() { return &_collector_state; } 989 990 // The current policy object for the collector. 991 G1Policy* policy() const { return _policy; } 992 // The remembered set. 993 G1RemSet* rem_set() const { return _rem_set; } 994 995 inline G1GCPhaseTimes* phase_times() const; 996 997 HeapRegionManager* hrm() const { return _hrm; } 998 999 const G1CollectionSet* collection_set() const { return &_collection_set; } 1000 G1CollectionSet* collection_set() { return &_collection_set; } 1001 1002 virtual SoftRefPolicy* soft_ref_policy(); 1003 1004 virtual void initialize_serviceability(); 1005 virtual MemoryUsage memory_usage(); 1006 virtual GrowableArray<GCMemoryManager*> memory_managers(); 1007 virtual GrowableArray<MemoryPool*> memory_pools(); 1008 1009 // Try to minimize the remembered set. 1010 void scrub_rem_set(); 1011 1012 // Apply the given closure on all cards in the Hot Card Cache, emptying it. 1013 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id); 1014 1015 // The shared block offset table array. 1016 G1BlockOffsetTable* bot() const { return _bot; } 1017 1018 // Reference Processing accessors 1019 1020 // The STW reference processor.... 1021 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 1022 1023 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; } 1024 1025 // The Concurrent Marking reference processor... 1026 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 1027 1028 size_t unused_committed_regions_in_bytes() const; 1029 1030 virtual size_t capacity() const; 1031 virtual size_t used() const; 1032 // This should be called when we're not holding the heap lock. The 1033 // result might be a bit inaccurate. 1034 size_t used_unlocked() const; 1035 size_t recalculate_used() const; 1036 1037 // These virtual functions do the actual allocation. 1038 // Some heaps may offer a contiguous region for shared non-blocking 1039 // allocation, via inlined code (by exporting the address of the top and 1040 // end fields defining the extent of the contiguous allocation region.) 1041 // But G1CollectedHeap doesn't yet support this. 1042 1043 virtual bool is_maximal_no_gc() const { 1044 return _hrm->available() == 0; 1045 } 1046 1047 // Returns whether there are any regions left in the heap for allocation. 1048 bool has_regions_left_for_allocation() const { 1049 return !is_maximal_no_gc() || num_free_regions() != 0; 1050 } 1051 1052 // The current number of regions in the heap. 1053 uint num_regions() const { return _hrm->length(); } 1054 1055 // The max number of regions in the heap. 1056 uint max_regions() const { return _hrm->max_length(); } 1057 1058 // Max number of regions that can be comitted. 1059 uint max_expandable_regions() const { return _hrm->max_expandable_length(); } 1060 1061 // The number of regions that are completely free. 1062 uint num_free_regions() const { return _hrm->num_free_regions(); } 1063 1064 // The number of regions that can be allocated into. 1065 uint num_free_or_available_regions() const { return num_free_regions() + _hrm->available(); } 1066 1067 MemoryUsage get_auxiliary_data_memory_usage() const { 1068 return _hrm->get_auxiliary_data_memory_usage(); 1069 } 1070 1071 // The number of regions that are not completely free. 1072 uint num_used_regions() const { return num_regions() - num_free_regions(); } 1073 1074 #ifdef ASSERT 1075 bool is_on_master_free_list(HeapRegion* hr) { 1076 return _hrm->is_free(hr); 1077 } 1078 #endif // ASSERT 1079 1080 inline void old_set_add(HeapRegion* hr); 1081 inline void old_set_remove(HeapRegion* hr); 1082 1083 inline void archive_set_add(HeapRegion* hr); 1084 1085 size_t non_young_capacity_bytes() { 1086 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes; 1087 } 1088 1089 // Determine whether the given region is one that we are using as an 1090 // old GC alloc region. 1091 bool is_old_gc_alloc_region(HeapRegion* hr); 1092 1093 // Perform a collection of the heap; intended for use in implementing 1094 // "System.gc". This probably implies as full a collection as the 1095 // "CollectedHeap" supports. 1096 virtual void collect(GCCause::Cause cause); 1097 1098 // Perform a collection of the heap with the given cause. 1099 // Returns whether this collection actually executed. 1100 bool try_collect(GCCause::Cause cause); 1101 1102 // True iff an evacuation has failed in the most-recent collection. 1103 bool evacuation_failed() { return _evacuation_failed; } 1104 1105 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed); 1106 void prepend_to_freelist(FreeRegionList* list); 1107 void decrement_summary_bytes(size_t bytes); 1108 1109 virtual bool is_in(const void* p) const; 1110 #ifdef ASSERT 1111 // Returns whether p is in one of the available areas of the heap. Slow but 1112 // extensive version. 1113 bool is_in_exact(const void* p) const; 1114 #endif 1115 1116 // Return "TRUE" iff the given object address is within the collection 1117 // set. Assumes that the reference points into the heap. 1118 inline bool is_in_cset(const HeapRegion *hr); 1119 inline bool is_in_cset(oop obj); 1120 inline bool is_in_cset(HeapWord* addr); 1121 1122 inline bool is_in_cset_or_humongous(const oop obj); 1123 1124 private: 1125 // This array is used for a quick test on whether a reference points into 1126 // the collection set or not. Each of the array's elements denotes whether the 1127 // corresponding region is in the collection set or not. 1128 G1HeapRegionAttrBiasedMappedArray _region_attr; 1129 1130 public: 1131 1132 inline G1HeapRegionAttr region_attr(const void* obj) const; 1133 inline G1HeapRegionAttr region_attr(uint idx) const; 1134 1135 // Return "TRUE" iff the given object address is in the reserved 1136 // region of g1. 1137 bool is_in_g1_reserved(const void* p) const { 1138 return _hrm->reserved().contains(p); 1139 } 1140 1141 // Returns a MemRegion that corresponds to the space that has been 1142 // reserved for the heap 1143 MemRegion g1_reserved() const { 1144 return _hrm->reserved(); 1145 } 1146 1147 MemRegion reserved_region() const { 1148 return _reserved; 1149 } 1150 1151 HeapWord* base() const { 1152 return _reserved.start(); 1153 } 1154 1155 bool is_in_reserved(const void* addr) const { 1156 return _reserved.contains(addr); 1157 } 1158 1159 G1HotCardCache* hot_card_cache() const { return _hot_card_cache; } 1160 1161 G1CardTable* card_table() const { 1162 return _card_table; 1163 } 1164 1165 // Iteration functions. 1166 1167 // Iterate over all objects, calling "cl.do_object" on each. 1168 virtual void object_iterate(ObjectClosure* cl); 1169 1170 virtual void safe_object_iterate(ObjectClosure* cl) { 1171 object_iterate(cl); 1172 } 1173 1174 // Iterate over heap regions, in address order, terminating the 1175 // iteration early if the "do_heap_region" method returns "true". 1176 void heap_region_iterate(HeapRegionClosure* blk) const; 1177 1178 // Return the region with the given index. It assumes the index is valid. 1179 inline HeapRegion* region_at(uint index) const; 1180 inline HeapRegion* region_at_or_null(uint index) const; 1181 1182 // Return the next region (by index) that is part of the same 1183 // humongous object that hr is part of. 1184 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const; 1185 1186 // Calculate the region index of the given address. Given address must be 1187 // within the heap. 1188 inline uint addr_to_region(HeapWord* addr) const; 1189 1190 inline HeapWord* bottom_addr_for_region(uint index) const; 1191 1192 // Two functions to iterate over the heap regions in parallel. Threads 1193 // compete using the HeapRegionClaimer to claim the regions before 1194 // applying the closure on them. 1195 // The _from_worker_offset version uses the HeapRegionClaimer and 1196 // the worker id to calculate a start offset to prevent all workers to 1197 // start from the point. 1198 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl, 1199 HeapRegionClaimer* hrclaimer, 1200 uint worker_id) const; 1201 1202 void heap_region_par_iterate_from_start(HeapRegionClosure* cl, 1203 HeapRegionClaimer* hrclaimer) const; 1204 1205 // Iterate over all regions currently in the current collection set. 1206 void collection_set_iterate_all(HeapRegionClosure* blk); 1207 1208 // Iterate over the regions in the current increment of the collection set. 1209 // Starts the iteration so that the start regions of a given worker id over the 1210 // set active_workers are evenly spread across the set of collection set regions 1211 // to be iterated. 1212 // The variant with the HeapRegionClaimer guarantees that the closure will be 1213 // applied to a particular region exactly once. 1214 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) { 1215 collection_set_iterate_increment_from(blk, NULL, worker_id); 1216 } 1217 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id); 1218 1219 // Returns the HeapRegion that contains addr. addr must not be NULL. 1220 template <class T> 1221 inline HeapRegion* heap_region_containing(const T addr) const; 1222 1223 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted 1224 // region. addr must not be NULL. 1225 template <class T> 1226 inline HeapRegion* heap_region_containing_or_null(const T addr) const; 1227 1228 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1229 // each address in the (reserved) heap is a member of exactly 1230 // one block. The defining characteristic of a block is that it is 1231 // possible to find its size, and thus to progress forward to the next 1232 // block. (Blocks may be of different sizes.) Thus, blocks may 1233 // represent Java objects, or they might be free blocks in a 1234 // free-list-based heap (or subheap), as long as the two kinds are 1235 // distinguishable and the size of each is determinable. 1236 1237 // Returns the address of the start of the "block" that contains the 1238 // address "addr". We say "blocks" instead of "object" since some heaps 1239 // may not pack objects densely; a chunk may either be an object or a 1240 // non-object. 1241 HeapWord* block_start(const void* addr) const; 1242 1243 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1244 // the block is an object. 1245 bool block_is_obj(const HeapWord* addr) const; 1246 1247 // Section on thread-local allocation buffers (TLABs) 1248 // See CollectedHeap for semantics. 1249 1250 bool supports_tlab_allocation() const; 1251 size_t tlab_capacity(Thread* ignored) const; 1252 size_t tlab_used(Thread* ignored) const; 1253 size_t max_tlab_size() const; 1254 size_t unsafe_max_tlab_alloc(Thread* ignored) const; 1255 1256 inline bool is_in_young(const oop obj); 1257 1258 // Returns "true" iff the given word_size is "very large". 1259 static bool is_humongous(size_t word_size) { 1260 // Note this has to be strictly greater-than as the TLABs 1261 // are capped at the humongous threshold and we want to 1262 // ensure that we don't try to allocate a TLAB as 1263 // humongous and that we don't allocate a humongous 1264 // object in a TLAB. 1265 return word_size > _humongous_object_threshold_in_words; 1266 } 1267 1268 // Returns the humongous threshold for a specific region size 1269 static size_t humongous_threshold_for(size_t region_size) { 1270 return (region_size / 2); 1271 } 1272 1273 // Returns the number of regions the humongous object of the given word size 1274 // requires. 1275 static size_t humongous_obj_size_in_regions(size_t word_size); 1276 1277 // Print the maximum heap capacity. 1278 virtual size_t max_capacity() const; 1279 1280 // Return the size of reserved memory. Returns different value than max_capacity() when AllocateOldGenAt is used. 1281 virtual size_t max_reserved_capacity() const; 1282 1283 virtual jlong millis_since_last_gc(); 1284 1285 1286 // Convenience function to be used in situations where the heap type can be 1287 // asserted to be this type. 1288 static G1CollectedHeap* heap(); 1289 1290 void set_region_short_lived_locked(HeapRegion* hr); 1291 // add appropriate methods for any other surv rate groups 1292 1293 const G1SurvivorRegions* survivor() const { return &_survivor; } 1294 1295 uint eden_regions_count() const { return _eden.length(); } 1296 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); } 1297 uint survivor_regions_count() const { return _survivor.length(); } 1298 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); } 1299 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); } 1300 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); } 1301 uint young_regions_count() const { return _eden.length() + _survivor.length(); } 1302 uint old_regions_count() const { return _old_set.length(); } 1303 uint archive_regions_count() const { return _archive_set.length(); } 1304 uint humongous_regions_count() const { return _humongous_set.length(); } 1305 1306 #ifdef ASSERT 1307 bool check_young_list_empty(); 1308 #endif 1309 1310 // *** Stuff related to concurrent marking. It's not clear to me that so 1311 // many of these need to be public. 1312 1313 // The functions below are helper functions that a subclass of 1314 // "CollectedHeap" can use in the implementation of its virtual 1315 // functions. 1316 // This performs a concurrent marking of the live objects in a 1317 // bitmap off to the side. 1318 void do_concurrent_mark(); 1319 1320 bool is_marked_next(oop obj) const; 1321 1322 // Determine if an object is dead, given the object and also 1323 // the region to which the object belongs. An object is dead 1324 // iff a) it was not allocated since the last mark, b) it 1325 // is not marked, and c) it is not in an archive region. 1326 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1327 return 1328 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) && 1329 !hr->is_archive(); 1330 } 1331 1332 // This function returns true when an object has been 1333 // around since the previous marking and hasn't yet 1334 // been marked during this marking, and is not in an archive region. 1335 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1336 return 1337 !hr->obj_allocated_since_next_marking(obj) && 1338 !is_marked_next(obj) && 1339 !hr->is_archive(); 1340 } 1341 1342 // Determine if an object is dead, given only the object itself. 1343 // This will find the region to which the object belongs and 1344 // then call the region version of the same function. 1345 1346 // Added if it is NULL it isn't dead. 1347 1348 inline bool is_obj_dead(const oop obj) const; 1349 1350 inline bool is_obj_ill(const oop obj) const; 1351 1352 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const; 1353 inline bool is_obj_dead_full(const oop obj) const; 1354 1355 G1ConcurrentMark* concurrent_mark() const { return _cm; } 1356 1357 // Refinement 1358 1359 G1ConcurrentRefine* concurrent_refine() const { return _cr; } 1360 1361 // Optimized nmethod scanning support routines 1362 1363 // Register the given nmethod with the G1 heap. 1364 virtual void register_nmethod(nmethod* nm); 1365 1366 // Unregister the given nmethod from the G1 heap. 1367 virtual void unregister_nmethod(nmethod* nm); 1368 1369 // No nmethod flushing needed. 1370 virtual void flush_nmethod(nmethod* nm) {} 1371 1372 // No nmethod verification implemented. 1373 virtual void verify_nmethod(nmethod* nm) {} 1374 1375 // Free up superfluous code root memory. 1376 void purge_code_root_memory(); 1377 1378 // Rebuild the strong code root lists for each region 1379 // after a full GC. 1380 void rebuild_strong_code_roots(); 1381 1382 // Partial cleaning of VM internal data structures. 1383 void string_dedup_cleaning(BoolObjectClosure* is_alive, 1384 OopClosure* keep_alive, 1385 G1GCPhaseTimes* phase_times = NULL); 1386 1387 // Performs cleaning of data structures after class unloading. 1388 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred); 1389 1390 // Redirty logged cards in the refinement queue. 1391 void redirty_logged_cards(G1RedirtyCardsQueueSet* rdcqs); 1392 1393 // Verification 1394 1395 // Deduplicate the string 1396 virtual void deduplicate_string(oop str); 1397 1398 // Perform any cleanup actions necessary before allowing a verification. 1399 virtual void prepare_for_verify(); 1400 1401 // Perform verification. 1402 1403 // vo == UsePrevMarking -> use "prev" marking information, 1404 // vo == UseNextMarking -> use "next" marking information 1405 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS 1406 // 1407 // NOTE: Only the "prev" marking information is guaranteed to be 1408 // consistent most of the time, so most calls to this should use 1409 // vo == UsePrevMarking. 1410 // Currently, there is only one case where this is called with 1411 // vo == UseNextMarking, which is to verify the "next" marking 1412 // information at the end of remark. 1413 // Currently there is only one place where this is called with 1414 // vo == UseFullMarking, which is to verify the marking during a 1415 // full GC. 1416 void verify(VerifyOption vo); 1417 1418 // WhiteBox testing support. 1419 virtual bool supports_concurrent_phase_control() const; 1420 virtual bool request_concurrent_phase(const char* phase); 1421 bool is_heterogeneous_heap() const; 1422 1423 virtual WorkGang* get_safepoint_workers() { return _workers; } 1424 1425 // The methods below are here for convenience and dispatch the 1426 // appropriate method depending on value of the given VerifyOption 1427 // parameter. The values for that parameter, and their meanings, 1428 // are the same as those above. 1429 1430 bool is_obj_dead_cond(const oop obj, 1431 const HeapRegion* hr, 1432 const VerifyOption vo) const; 1433 1434 bool is_obj_dead_cond(const oop obj, 1435 const VerifyOption vo) const; 1436 1437 G1HeapSummary create_g1_heap_summary(); 1438 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats); 1439 1440 // Printing 1441 private: 1442 void print_heap_regions() const; 1443 void print_regions_on(outputStream* st) const; 1444 1445 public: 1446 virtual void print_on(outputStream* st) const; 1447 virtual void print_extended_on(outputStream* st) const; 1448 virtual void print_on_error(outputStream* st) const; 1449 1450 virtual void print_gc_threads_on(outputStream* st) const; 1451 virtual void gc_threads_do(ThreadClosure* tc) const; 1452 1453 // Override 1454 void print_tracing_info() const; 1455 1456 // The following two methods are helpful for debugging RSet issues. 1457 void print_cset_rsets() PRODUCT_RETURN; 1458 void print_all_rsets() PRODUCT_RETURN; 1459 1460 // Used to print information about locations in the hs_err file. 1461 virtual bool print_location(outputStream* st, void* addr) const; 1462 1463 size_t pending_card_num(); 1464 }; 1465 1466 class G1ParEvacuateFollowersClosure : public VoidClosure { 1467 private: 1468 double _start_term; 1469 double _term_time; 1470 size_t _term_attempts; 1471 1472 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); } 1473 void end_term_time() { _term_time += (os::elapsedTime() - _start_term); } 1474 protected: 1475 G1CollectedHeap* _g1h; 1476 G1ParScanThreadState* _par_scan_state; 1477 RefToScanQueueSet* _queues; 1478 ParallelTaskTerminator* _terminator; 1479 G1GCPhaseTimes::GCParPhases _phase; 1480 1481 G1ParScanThreadState* par_scan_state() { return _par_scan_state; } 1482 RefToScanQueueSet* queues() { return _queues; } 1483 ParallelTaskTerminator* terminator() { return _terminator; } 1484 1485 public: 1486 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h, 1487 G1ParScanThreadState* par_scan_state, 1488 RefToScanQueueSet* queues, 1489 ParallelTaskTerminator* terminator, 1490 G1GCPhaseTimes::GCParPhases phase) 1491 : _start_term(0.0), _term_time(0.0), _term_attempts(0), 1492 _g1h(g1h), _par_scan_state(par_scan_state), 1493 _queues(queues), _terminator(terminator), _phase(phase) {} 1494 1495 void do_void(); 1496 1497 double term_time() const { return _term_time; } 1498 size_t term_attempts() const { return _term_attempts; } 1499 1500 private: 1501 inline bool offer_termination(); 1502 }; 1503 1504 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP