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 VMStructs; 137 friend class MutatorAllocRegion; 138 friend class G1FullCollector; 139 friend class G1GCAllocRegion; 140 friend class G1HeapVerifier; 141 142 // Closures used in implementation. 143 friend class G1ParScanThreadState; 144 friend class G1ParScanThreadStateSet; 145 friend class G1EvacuateRegionsTask; 146 friend class G1PLABAllocator; 147 148 // Other related classes. 149 friend class HeapRegionClaimer; 150 151 // Testing classes. 152 friend class G1CheckRegionAttrTableClosure; 153 154 private: 155 G1YoungRemSetSamplingThread* _young_gen_sampling_thread; 156 157 WorkGang* _workers; 158 G1CardTable* _card_table; 159 160 SoftRefPolicy _soft_ref_policy; 161 162 static size_t _humongous_object_threshold_in_words; 163 164 // These sets keep track of old, archive and humongous regions respectively. 165 HeapRegionSet _old_set; 166 HeapRegionSet _archive_set; 167 HeapRegionSet _humongous_set; 168 169 void eagerly_reclaim_humongous_regions(); 170 // Start a new incremental collection set for the next pause. 171 void start_new_collection_set(); 172 173 // The block offset table for the G1 heap. 174 G1BlockOffsetTable* _bot; 175 176 // Tears down the region sets / lists so that they are empty and the 177 // regions on the heap do not belong to a region set / list. The 178 // only exception is the humongous set which we leave unaltered. If 179 // free_list_only is true, it will only tear down the master free 180 // list. It is called before a Full GC (free_list_only == false) or 181 // before heap shrinking (free_list_only == true). 182 void tear_down_region_sets(bool free_list_only); 183 184 // Rebuilds the region sets / lists so that they are repopulated to 185 // reflect the contents of the heap. The only exception is the 186 // humongous set which was not torn down in the first place. If 187 // free_list_only is true, it will only rebuild the master free 188 // list. It is called after a Full GC (free_list_only == false) or 189 // after heap shrinking (free_list_only == true). 190 void rebuild_region_sets(bool free_list_only); 191 192 // Callback for region mapping changed events. 193 G1RegionMappingChangedListener _listener; 194 195 // Handle G1 NUMA support. 196 G1NUMA* _numa; 197 198 // The sequence of all heap regions in the heap. 199 HeapRegionManager* _hrm; 200 201 // Manages all allocations with regions except humongous object allocations. 202 G1Allocator* _allocator; 203 204 // Manages all heap verification. 205 G1HeapVerifier* _verifier; 206 207 // Outside of GC pauses, the number of bytes used in all regions other 208 // than the current allocation region(s). 209 volatile size_t _summary_bytes_used; 210 211 void increase_used(size_t bytes); 212 void decrease_used(size_t bytes); 213 214 void set_used(size_t bytes); 215 216 // Class that handles archive allocation ranges. 217 G1ArchiveAllocator* _archive_allocator; 218 219 // GC allocation statistics policy for survivors. 220 G1EvacStats _survivor_evac_stats; 221 222 // GC allocation statistics policy for tenured objects. 223 G1EvacStats _old_evac_stats; 224 225 // It specifies whether we should attempt to expand the heap after a 226 // region allocation failure. If heap expansion fails we set this to 227 // false so that we don't re-attempt the heap expansion (it's likely 228 // that subsequent expansion attempts will also fail if one fails). 229 // Currently, it is only consulted during GC and it's reset at the 230 // start of each GC. 231 bool _expand_heap_after_alloc_failure; 232 233 // Helper for monitoring and management support. 234 G1MonitoringSupport* _g1mm; 235 236 // Records whether the region at the given index is (still) a 237 // candidate for eager reclaim. Only valid for humongous start 238 // regions; other regions have unspecified values. Humongous start 239 // regions are initialized at start of collection pause, with 240 // candidates removed from the set as they are found reachable from 241 // roots or the young generation. 242 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> { 243 protected: 244 bool default_value() const { return false; } 245 public: 246 void clear() { G1BiasedMappedArray<bool>::clear(); } 247 void set_candidate(uint region, bool value) { 248 set_by_index(region, value); 249 } 250 bool is_candidate(uint region) { 251 return get_by_index(region); 252 } 253 }; 254 255 HumongousReclaimCandidates _humongous_reclaim_candidates; 256 // Stores whether during humongous object registration we found candidate regions. 257 // If not, we can skip a few steps. 258 bool _has_humongous_reclaim_candidates; 259 260 G1HRPrinter _hr_printer; 261 262 // It decides whether an explicit GC should start a concurrent cycle 263 // instead of doing a STW GC. Currently, a concurrent cycle is 264 // explicitly started if: 265 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or 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 bool should_do_concurrent_full_gc(GCCause::Cause cause); 271 272 // Return true if should upgrade to full gc after an incremental one. 273 bool should_upgrade_to_full_gc(GCCause::Cause cause); 274 275 // indicates whether we are in young or mixed GC mode 276 G1CollectorState _collector_state; 277 278 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 279 // concurrent cycles) we have started. 280 volatile uint _old_marking_cycles_started; 281 282 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 283 // concurrent cycles) we have completed. 284 volatile uint _old_marking_cycles_completed; 285 286 // This is a non-product method that is helpful for testing. It is 287 // called at the end of a GC and artificially expands the heap by 288 // allocating a number of dead regions. This way we can induce very 289 // frequent marking cycles and stress the cleanup / concurrent 290 // cleanup code more (as all the regions that will be allocated by 291 // this method will be found dead by the marking cycle). 292 void allocate_dummy_regions() PRODUCT_RETURN; 293 294 // If the HR printer is active, dump the state of the regions in the 295 // heap after a compaction. 296 void print_hrm_post_compaction(); 297 298 // Create a memory mapper for auxiliary data structures of the given size and 299 // translation factor. 300 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description, 301 size_t size, 302 size_t translation_factor); 303 304 void trace_heap(GCWhen::Type when, const GCTracer* tracer); 305 306 // These are macros so that, if the assert fires, we get the correct 307 // line number, file, etc. 308 309 #define heap_locking_asserts_params(_extra_message_) \ 310 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 311 (_extra_message_), \ 312 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 313 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 314 BOOL_TO_STR(Thread::current()->is_VM_thread()) 315 316 #define assert_heap_locked() \ 317 do { \ 318 assert(Heap_lock->owned_by_self(), \ 319 heap_locking_asserts_params("should be holding the Heap_lock")); \ 320 } while (0) 321 322 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 323 do { \ 324 assert(Heap_lock->owned_by_self() || \ 325 (SafepointSynchronize::is_at_safepoint() && \ 326 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 327 heap_locking_asserts_params("should be holding the Heap_lock or " \ 328 "should be at a safepoint")); \ 329 } while (0) 330 331 #define assert_heap_locked_and_not_at_safepoint() \ 332 do { \ 333 assert(Heap_lock->owned_by_self() && \ 334 !SafepointSynchronize::is_at_safepoint(), \ 335 heap_locking_asserts_params("should be holding the Heap_lock and " \ 336 "should not be at a safepoint")); \ 337 } while (0) 338 339 #define assert_heap_not_locked() \ 340 do { \ 341 assert(!Heap_lock->owned_by_self(), \ 342 heap_locking_asserts_params("should not be holding the Heap_lock")); \ 343 } while (0) 344 345 #define assert_heap_not_locked_and_not_at_safepoint() \ 346 do { \ 347 assert(!Heap_lock->owned_by_self() && \ 348 !SafepointSynchronize::is_at_safepoint(), \ 349 heap_locking_asserts_params("should not be holding the Heap_lock and " \ 350 "should not be at a safepoint")); \ 351 } while (0) 352 353 #define assert_at_safepoint_on_vm_thread() \ 354 do { \ 355 assert_at_safepoint(); \ 356 assert(Thread::current_or_null() != NULL, "no current thread"); \ 357 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \ 358 } while (0) 359 360 #ifdef ASSERT 361 #define assert_used_and_recalculate_used_equal(g1h) \ 362 do { \ 363 size_t cur_used_bytes = g1h->used(); \ 364 size_t recal_used_bytes = g1h->recalculate_used(); \ 365 assert(cur_used_bytes == recal_used_bytes, "Used(" SIZE_FORMAT ") is not" \ 366 " same as recalculated used(" SIZE_FORMAT ").", \ 367 cur_used_bytes, recal_used_bytes); \ 368 } while (0) 369 #else 370 #define assert_used_and_recalculate_used_equal(g1h) do {} while(0) 371 #endif 372 373 const char* young_gc_name() const; 374 375 // The young region list. 376 G1EdenRegions _eden; 377 G1SurvivorRegions _survivor; 378 379 STWGCTimer* _gc_timer_stw; 380 381 G1NewTracer* _gc_tracer_stw; 382 383 // The current policy object for the collector. 384 G1Policy* _policy; 385 G1HeapSizingPolicy* _heap_sizing_policy; 386 387 G1CollectionSet _collection_set; 388 389 // Try to allocate a single non-humongous HeapRegion sufficient for 390 // an allocation of the given word_size. If do_expand is true, 391 // attempt to expand the heap if necessary to satisfy the allocation 392 // request. 'type' takes the type of region to be allocated. (Use constants 393 // Old, Eden, Humongous, Survivor defined in HeapRegionType.) 394 HeapRegion* new_region(size_t word_size, 395 HeapRegionType type, 396 bool do_expand, 397 uint node_index = G1NUMA::AnyNodeIndex); 398 399 // Initialize a contiguous set of free regions of length num_regions 400 // and starting at index first so that they appear as a single 401 // humongous region. 402 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 403 uint num_regions, 404 size_t word_size); 405 406 // Attempt to allocate a humongous object of the given size. Return 407 // NULL if unsuccessful. 408 HeapWord* humongous_obj_allocate(size_t word_size); 409 410 // The following two methods, allocate_new_tlab() and 411 // mem_allocate(), are the two main entry points from the runtime 412 // into the G1's allocation routines. They have the following 413 // assumptions: 414 // 415 // * They should both be called outside safepoints. 416 // 417 // * They should both be called without holding the Heap_lock. 418 // 419 // * All allocation requests for new TLABs should go to 420 // allocate_new_tlab(). 421 // 422 // * All non-TLAB allocation requests should go to mem_allocate(). 423 // 424 // * If either call cannot satisfy the allocation request using the 425 // current allocating region, they will try to get a new one. If 426 // this fails, they will attempt to do an evacuation pause and 427 // retry the allocation. 428 // 429 // * If all allocation attempts fail, even after trying to schedule 430 // an evacuation pause, allocate_new_tlab() will return NULL, 431 // whereas mem_allocate() will attempt a heap expansion and/or 432 // schedule a Full GC. 433 // 434 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 435 // should never be called with word_size being humongous. All 436 // humongous allocation requests should go to mem_allocate() which 437 // will satisfy them with a special path. 438 439 virtual HeapWord* allocate_new_tlab(size_t min_size, 440 size_t requested_size, 441 size_t* actual_size); 442 443 virtual HeapWord* mem_allocate(size_t word_size, 444 bool* gc_overhead_limit_was_exceeded); 445 446 // First-level mutator allocation attempt: try to allocate out of 447 // the mutator alloc region without taking the Heap_lock. This 448 // should only be used for non-humongous allocations. 449 inline HeapWord* attempt_allocation(size_t min_word_size, 450 size_t desired_word_size, 451 size_t* actual_word_size); 452 453 // Second-level mutator allocation attempt: take the Heap_lock and 454 // retry the allocation attempt, potentially scheduling a GC 455 // pause. This should only be used for non-humongous allocations. 456 HeapWord* attempt_allocation_slow(size_t word_size); 457 458 // Takes the Heap_lock and attempts a humongous allocation. It can 459 // potentially schedule a GC pause. 460 HeapWord* attempt_allocation_humongous(size_t word_size); 461 462 // Allocation attempt that should be called during safepoints (e.g., 463 // at the end of a successful GC). expect_null_mutator_alloc_region 464 // specifies whether the mutator alloc region is expected to be NULL 465 // or not. 466 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 467 bool expect_null_mutator_alloc_region); 468 469 // These methods are the "callbacks" from the G1AllocRegion class. 470 471 // For mutator alloc regions. 472 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force, uint node_index); 473 void retire_mutator_alloc_region(HeapRegion* alloc_region, 474 size_t allocated_bytes); 475 476 // For GC alloc regions. 477 bool has_more_regions(G1HeapRegionAttr dest); 478 HeapRegion* new_gc_alloc_region(size_t word_size, G1HeapRegionAttr dest, uint node_index); 479 void retire_gc_alloc_region(HeapRegion* alloc_region, 480 size_t allocated_bytes, G1HeapRegionAttr dest); 481 482 // - if explicit_gc is true, the GC is for a System.gc() etc, 483 // otherwise it's for a failed allocation. 484 // - if clear_all_soft_refs is true, all soft references should be 485 // cleared during the GC. 486 // - it returns false if it is unable to do the collection due to the 487 // GC locker being active, true otherwise. 488 bool do_full_collection(bool explicit_gc, 489 bool clear_all_soft_refs); 490 491 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread. 492 virtual void do_full_collection(bool clear_all_soft_refs); 493 494 // Callback from VM_G1CollectForAllocation operation. 495 // This function does everything necessary/possible to satisfy a 496 // failed allocation request (including collection, expansion, etc.) 497 HeapWord* satisfy_failed_allocation(size_t word_size, 498 bool* succeeded); 499 // Internal helpers used during full GC to split it up to 500 // increase readability. 501 void abort_concurrent_cycle(); 502 void verify_before_full_collection(bool explicit_gc); 503 void prepare_heap_for_full_collection(); 504 void prepare_heap_for_mutators(); 505 void abort_refinement(); 506 void verify_after_full_collection(); 507 void print_heap_after_full_collection(G1HeapTransition* heap_transition); 508 509 // Helper method for satisfy_failed_allocation() 510 HeapWord* satisfy_failed_allocation_helper(size_t word_size, 511 bool do_gc, 512 bool clear_all_soft_refs, 513 bool expect_null_mutator_alloc_region, 514 bool* gc_succeeded); 515 516 // Attempting to expand the heap sufficiently 517 // to support an allocation of the given "word_size". If 518 // successful, perform the allocation and return the address of the 519 // allocated block, or else "NULL". 520 HeapWord* expand_and_allocate(size_t word_size); 521 522 // Process any reference objects discovered. 523 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states); 524 525 // If during an initial mark pause we may install a pending list head which is not 526 // otherwise reachable ensure that it is marked in the bitmap for concurrent marking 527 // to discover. 528 void make_pending_list_reachable(); 529 530 // Merges the information gathered on a per-thread basis for all worker threads 531 // during GC into global variables. 532 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states); 533 534 void verify_numa_regions(const char* desc); 535 536 public: 537 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; } 538 539 WorkGang* workers() const { return _workers; } 540 541 // Runs the given AbstractGangTask with the current active workers, returning the 542 // total time taken. 543 Tickspan run_task(AbstractGangTask* task); 544 545 G1Allocator* allocator() { 546 return _allocator; 547 } 548 549 G1HeapVerifier* verifier() { 550 return _verifier; 551 } 552 553 G1MonitoringSupport* g1mm() { 554 assert(_g1mm != NULL, "should have been initialized"); 555 return _g1mm; 556 } 557 558 void resize_heap_if_necessary(); 559 560 G1NUMA* numa() const { return _numa; } 561 562 // Expand the garbage-first heap by at least the given size (in bytes!). 563 // Returns true if the heap was expanded by the requested amount; 564 // false otherwise. 565 // (Rounds up to a HeapRegion boundary.) 566 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL); 567 bool expand_single_region(uint node_index); 568 569 // Returns the PLAB statistics for a given destination. 570 inline G1EvacStats* alloc_buffer_stats(G1HeapRegionAttr dest); 571 572 // Determines PLAB size for a given destination. 573 inline size_t desired_plab_sz(G1HeapRegionAttr dest); 574 575 // Do anything common to GC's. 576 void gc_prologue(bool full); 577 void gc_epilogue(bool full); 578 579 // Does the given region fulfill remembered set based eager reclaim candidate requirements? 580 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const; 581 582 // Modify the reclaim candidate set and test for presence. 583 // These are only valid for starts_humongous regions. 584 inline void set_humongous_reclaim_candidate(uint region, bool value); 585 inline bool is_humongous_reclaim_candidate(uint region); 586 587 // Remove from the reclaim candidate set. Also remove from the 588 // collection set so that later encounters avoid the slow path. 589 inline void set_humongous_is_live(oop obj); 590 591 // Register the given region to be part of the collection set. 592 inline void register_humongous_region_with_region_attr(uint index); 593 // Update region attributes table with information about all regions. 594 void register_regions_with_region_attr(); 595 // We register a region with the fast "in collection set" test. We 596 // simply set to true the array slot corresponding to this region. 597 void register_young_region_with_region_attr(HeapRegion* r) { 598 _region_attr.set_in_young(r->hrm_index()); 599 } 600 inline void register_region_with_region_attr(HeapRegion* r); 601 inline void register_old_region_with_region_attr(HeapRegion* r); 602 inline void register_optional_region_with_region_attr(HeapRegion* r); 603 604 void clear_region_attr(const HeapRegion* hr) { 605 _region_attr.clear(hr); 606 } 607 608 void clear_region_attr() { 609 _region_attr.clear(); 610 } 611 612 // Verify that the G1RegionAttr remset tracking corresponds to actual remset tracking 613 // for all regions. 614 void verify_region_attr_remset_update() PRODUCT_RETURN; 615 616 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause); 617 618 // This is called at the start of either a concurrent cycle or a Full 619 // GC to update the number of old marking cycles started. 620 void increment_old_marking_cycles_started(); 621 622 // This is called at the end of either a concurrent cycle or a Full 623 // GC to update the number of old marking cycles completed. Those two 624 // can happen in a nested fashion, i.e., we start a concurrent 625 // cycle, a Full GC happens half-way through it which ends first, 626 // and then the cycle notices that a Full GC happened and ends 627 // too. The concurrent parameter is a boolean to help us do a bit 628 // tighter consistency checking in the method. If concurrent is 629 // false, the caller is the inner caller in the nesting (i.e., the 630 // Full GC). If concurrent is true, the caller is the outer caller 631 // in this nesting (i.e., the concurrent cycle). Further nesting is 632 // not currently supported. The end of this call also notifies 633 // the FullGCCount_lock in case a Java thread is waiting for a full 634 // GC to happen (e.g., it called System.gc() with 635 // +ExplicitGCInvokesConcurrent). 636 void increment_old_marking_cycles_completed(bool concurrent); 637 638 uint old_marking_cycles_completed() { 639 return _old_marking_cycles_completed; 640 } 641 642 G1HRPrinter* hr_printer() { return &_hr_printer; } 643 644 // Allocates a new heap region instance. 645 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr); 646 647 // Allocate the highest free region in the reserved heap. This will commit 648 // regions as necessary. 649 HeapRegion* alloc_highest_free_region(); 650 651 // Frees a non-humongous region by initializing its contents and 652 // adding it to the free list that's passed as a parameter (this is 653 // usually a local list which will be appended to the master free 654 // list later). The used bytes of freed regions are accumulated in 655 // pre_used. If skip_remset is true, the region's RSet will not be freed 656 // up. If skip_hot_card_cache is true, the region's hot card cache will not 657 // be freed up. The assumption is that this will be done later. 658 // The locked parameter indicates if the caller has already taken 659 // care of proper synchronization. This may allow some optimizations. 660 void free_region(HeapRegion* hr, 661 FreeRegionList* free_list, 662 bool skip_remset, 663 bool skip_hot_card_cache = false, 664 bool locked = false); 665 666 // It dirties the cards that cover the block so that the post 667 // write barrier never queues anything when updating objects on this 668 // block. It is assumed (and in fact we assert) that the block 669 // belongs to a young region. 670 inline void dirty_young_block(HeapWord* start, size_t word_size); 671 672 // Frees a humongous region by collapsing it into individual regions 673 // and calling free_region() for each of them. The freed regions 674 // will be added to the free list that's passed as a parameter (this 675 // is usually a local list which will be appended to the master free 676 // list later). 677 // The method assumes that only a single thread is ever calling 678 // this for a particular region at once. 679 void free_humongous_region(HeapRegion* hr, 680 FreeRegionList* free_list); 681 682 // Facility for allocating in 'archive' regions in high heap memory and 683 // recording the allocated ranges. These should all be called from the 684 // VM thread at safepoints, without the heap lock held. They can be used 685 // to create and archive a set of heap regions which can be mapped at the 686 // same fixed addresses in a subsequent JVM invocation. 687 void begin_archive_alloc_range(bool open = false); 688 689 // Check if the requested size would be too large for an archive allocation. 690 bool is_archive_alloc_too_large(size_t word_size); 691 692 // Allocate memory of the requested size from the archive region. This will 693 // return NULL if the size is too large or if no memory is available. It 694 // does not trigger a garbage collection. 695 HeapWord* archive_mem_allocate(size_t word_size); 696 697 // Optionally aligns the end address and returns the allocated ranges in 698 // an array of MemRegions in order of ascending addresses. 699 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges, 700 size_t end_alignment_in_bytes = 0); 701 702 // Facility for allocating a fixed range within the heap and marking 703 // the containing regions as 'archive'. For use at JVM init time, when the 704 // caller may mmap archived heap data at the specified range(s). 705 // Verify that the MemRegions specified in the argument array are within the 706 // reserved heap. 707 bool check_archive_addresses(MemRegion* range, size_t count); 708 709 // Commit the appropriate G1 regions containing the specified MemRegions 710 // and mark them as 'archive' regions. The regions in the array must be 711 // non-overlapping and in order of ascending address. 712 bool alloc_archive_regions(MemRegion* range, size_t count, bool open); 713 714 // Insert any required filler objects in the G1 regions around the specified 715 // ranges to make the regions parseable. This must be called after 716 // alloc_archive_regions, and after class loading has occurred. 717 void fill_archive_regions(MemRegion* range, size_t count); 718 719 // For each of the specified MemRegions, uncommit the containing G1 regions 720 // which had been allocated by alloc_archive_regions. This should be called 721 // rather than fill_archive_regions at JVM init time if the archive file 722 // mapping failed, with the same non-overlapping and sorted MemRegion array. 723 void dealloc_archive_regions(MemRegion* range, size_t count, bool is_open); 724 725 oop materialize_archived_object(oop obj); 726 727 private: 728 729 // Shrink the garbage-first heap by at most the given size (in bytes!). 730 // (Rounds down to a HeapRegion boundary.) 731 void shrink(size_t expand_bytes); 732 void shrink_helper(size_t expand_bytes); 733 734 #if TASKQUEUE_STATS 735 static void print_taskqueue_stats_hdr(outputStream* const st); 736 void print_taskqueue_stats() const; 737 void reset_taskqueue_stats(); 738 #endif // TASKQUEUE_STATS 739 740 // Schedule the VM operation that will do an evacuation pause to 741 // satisfy an allocation request of word_size. *succeeded will 742 // return whether the VM operation was successful (it did do an 743 // evacuation pause) or not (another thread beat us to it or the GC 744 // locker was active). Given that we should not be holding the 745 // Heap_lock when we enter this method, we will pass the 746 // gc_count_before (i.e., total_collections()) as a parameter since 747 // it has to be read while holding the Heap_lock. Currently, both 748 // methods that call do_collection_pause() release the Heap_lock 749 // before the call, so it's easy to read gc_count_before just before. 750 HeapWord* do_collection_pause(size_t word_size, 751 uint gc_count_before, 752 bool* succeeded, 753 GCCause::Cause gc_cause); 754 755 void wait_for_root_region_scanning(); 756 757 // The guts of the incremental collection pause, executed by the vm 758 // thread. It returns false if it is unable to do the collection due 759 // to the GC locker being active, true otherwise 760 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 761 762 G1HeapVerifier::G1VerifyType young_collection_verify_type() const; 763 void verify_before_young_collection(G1HeapVerifier::G1VerifyType type); 764 void verify_after_young_collection(G1HeapVerifier::G1VerifyType type); 765 766 void calculate_collection_set(G1EvacuationInfo& evacuation_info, double target_pause_time_ms); 767 768 // Actually do the work of evacuating the parts of the collection set. 769 void evacuate_initial_collection_set(G1ParScanThreadStateSet* per_thread_states); 770 void evacuate_optional_collection_set(G1ParScanThreadStateSet* per_thread_states); 771 private: 772 // Evacuate the next set of optional regions. 773 void evacuate_next_optional_regions(G1ParScanThreadStateSet* per_thread_states); 774 775 public: 776 void pre_evacuate_collection_set(G1EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss); 777 void post_evacuate_collection_set(G1EvacuationInfo& evacuation_info, 778 G1RedirtyCardsQueueSet* rdcqs, 779 G1ParScanThreadStateSet* pss); 780 781 void expand_heap_after_young_collection(); 782 // Update object copying statistics. 783 void record_obj_copy_mem_stats(); 784 785 // The hot card cache for remembered set insertion optimization. 786 G1HotCardCache* _hot_card_cache; 787 788 // The g1 remembered set of the heap. 789 G1RemSet* _rem_set; 790 791 // After a collection pause, convert the regions in the collection set into free 792 // regions. 793 void free_collection_set(G1CollectionSet* collection_set, G1EvacuationInfo& evacuation_info, const size_t* surviving_young_words); 794 795 // Abandon the current collection set without recording policy 796 // statistics or updating free lists. 797 void abandon_collection_set(G1CollectionSet* collection_set); 798 799 // The concurrent marker (and the thread it runs in.) 800 G1ConcurrentMark* _cm; 801 G1ConcurrentMarkThread* _cm_thread; 802 803 // The concurrent refiner. 804 G1ConcurrentRefine* _cr; 805 806 // The parallel task queues 807 RefToScanQueueSet *_task_queues; 808 809 // True iff a evacuation has failed in the current collection. 810 bool _evacuation_failed; 811 812 EvacuationFailedInfo* _evacuation_failed_info_array; 813 814 // Failed evacuations cause some logical from-space objects to have 815 // forwarding pointers to themselves. Reset them. 816 void remove_self_forwarding_pointers(G1RedirtyCardsQueueSet* rdcqs); 817 818 // Restore the objects in the regions in the collection set after an 819 // evacuation failure. 820 void restore_after_evac_failure(G1RedirtyCardsQueueSet* rdcqs); 821 822 PreservedMarksSet _preserved_marks_set; 823 824 // Preserve the mark of "obj", if necessary, in preparation for its mark 825 // word being overwritten with a self-forwarding-pointer. 826 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markWord m); 827 828 #ifndef PRODUCT 829 // Support for forcing evacuation failures. Analogous to 830 // PromotionFailureALot for the other collectors. 831 832 // Records whether G1EvacuationFailureALot should be in effect 833 // for the current GC 834 bool _evacuation_failure_alot_for_current_gc; 835 836 // Used to record the GC number for interval checking when 837 // determining whether G1EvaucationFailureALot is in effect 838 // for the current GC. 839 size_t _evacuation_failure_alot_gc_number; 840 841 // Count of the number of evacuations between failures. 842 volatile size_t _evacuation_failure_alot_count; 843 844 // Set whether G1EvacuationFailureALot should be in effect 845 // for the current GC (based upon the type of GC and which 846 // command line flags are set); 847 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc, 848 bool during_initial_mark, 849 bool mark_or_rebuild_in_progress); 850 851 inline void set_evacuation_failure_alot_for_current_gc(); 852 853 // Return true if it's time to cause an evacuation failure. 854 inline bool evacuation_should_fail(); 855 856 // Reset the G1EvacuationFailureALot counters. Should be called at 857 // the end of an evacuation pause in which an evacuation failure occurred. 858 inline void reset_evacuation_should_fail(); 859 #endif // !PRODUCT 860 861 // ("Weak") Reference processing support. 862 // 863 // G1 has 2 instances of the reference processor class. One 864 // (_ref_processor_cm) handles reference object discovery 865 // and subsequent processing during concurrent marking cycles. 866 // 867 // The other (_ref_processor_stw) handles reference object 868 // discovery and processing during full GCs and incremental 869 // evacuation pauses. 870 // 871 // During an incremental pause, reference discovery will be 872 // temporarily disabled for _ref_processor_cm and will be 873 // enabled for _ref_processor_stw. At the end of the evacuation 874 // pause references discovered by _ref_processor_stw will be 875 // processed and discovery will be disabled. The previous 876 // setting for reference object discovery for _ref_processor_cm 877 // will be re-instated. 878 // 879 // At the start of marking: 880 // * Discovery by the CM ref processor is verified to be inactive 881 // and it's discovered lists are empty. 882 // * Discovery by the CM ref processor is then enabled. 883 // 884 // At the end of marking: 885 // * Any references on the CM ref processor's discovered 886 // lists are processed (possibly MT). 887 // 888 // At the start of full GC we: 889 // * Disable discovery by the CM ref processor and 890 // empty CM ref processor's discovered lists 891 // (without processing any entries). 892 // * Verify that the STW ref processor is inactive and it's 893 // discovered lists are empty. 894 // * Temporarily set STW ref processor discovery as single threaded. 895 // * Temporarily clear the STW ref processor's _is_alive_non_header 896 // field. 897 // * Finally enable discovery by the STW ref processor. 898 // 899 // The STW ref processor is used to record any discovered 900 // references during the full GC. 901 // 902 // At the end of a full GC we: 903 // * Enqueue any reference objects discovered by the STW ref processor 904 // that have non-live referents. This has the side-effect of 905 // making the STW ref processor inactive by disabling discovery. 906 // * Verify that the CM ref processor is still inactive 907 // and no references have been placed on it's discovered 908 // lists (also checked as a precondition during initial marking). 909 910 // The (stw) reference processor... 911 ReferenceProcessor* _ref_processor_stw; 912 913 // During reference object discovery, the _is_alive_non_header 914 // closure (if non-null) is applied to the referent object to 915 // determine whether the referent is live. If so then the 916 // reference object does not need to be 'discovered' and can 917 // be treated as a regular oop. This has the benefit of reducing 918 // the number of 'discovered' reference objects that need to 919 // be processed. 920 // 921 // Instance of the is_alive closure for embedding into the 922 // STW reference processor as the _is_alive_non_header field. 923 // Supplying a value for the _is_alive_non_header field is 924 // optional but doing so prevents unnecessary additions to 925 // the discovered lists during reference discovery. 926 G1STWIsAliveClosure _is_alive_closure_stw; 927 928 G1STWSubjectToDiscoveryClosure _is_subject_to_discovery_stw; 929 930 // The (concurrent marking) reference processor... 931 ReferenceProcessor* _ref_processor_cm; 932 933 // Instance of the concurrent mark is_alive closure for embedding 934 // into the Concurrent Marking reference processor as the 935 // _is_alive_non_header field. Supplying a value for the 936 // _is_alive_non_header field is optional but doing so prevents 937 // unnecessary additions to the discovered lists during reference 938 // discovery. 939 G1CMIsAliveClosure _is_alive_closure_cm; 940 941 G1CMSubjectToDiscoveryClosure _is_subject_to_discovery_cm; 942 public: 943 944 RefToScanQueue *task_queue(uint i) const; 945 946 uint num_task_queues() const; 947 948 // Create a G1CollectedHeap. 949 // Must call the initialize method afterwards. 950 // May not return if something goes wrong. 951 G1CollectedHeap(); 952 953 private: 954 jint initialize_concurrent_refinement(); 955 jint initialize_young_gen_sampling_thread(); 956 public: 957 // Initialize the G1CollectedHeap to have the initial and 958 // maximum sizes and remembered and barrier sets 959 // specified by the policy object. 960 jint initialize(); 961 962 virtual void stop(); 963 virtual void safepoint_synchronize_begin(); 964 virtual void safepoint_synchronize_end(); 965 966 // Does operations required after initialization has been done. 967 void post_initialize(); 968 969 // Initialize weak reference processing. 970 void ref_processing_init(); 971 972 virtual Name kind() const { 973 return CollectedHeap::G1; 974 } 975 976 virtual const char* name() const { 977 return "G1"; 978 } 979 980 const G1CollectorState* collector_state() const { return &_collector_state; } 981 G1CollectorState* collector_state() { return &_collector_state; } 982 983 // The current policy object for the collector. 984 G1Policy* policy() const { return _policy; } 985 // The remembered set. 986 G1RemSet* rem_set() const { return _rem_set; } 987 988 inline G1GCPhaseTimes* phase_times() const; 989 990 HeapRegionManager* hrm() const { return _hrm; } 991 992 const G1CollectionSet* collection_set() const { return &_collection_set; } 993 G1CollectionSet* collection_set() { return &_collection_set; } 994 995 virtual SoftRefPolicy* soft_ref_policy(); 996 997 virtual void initialize_serviceability(); 998 virtual MemoryUsage memory_usage(); 999 virtual GrowableArray<GCMemoryManager*> memory_managers(); 1000 virtual GrowableArray<MemoryPool*> memory_pools(); 1001 1002 // Try to minimize the remembered set. 1003 void scrub_rem_set(); 1004 1005 // Apply the given closure on all cards in the Hot Card Cache, emptying it. 1006 void iterate_hcc_closure(G1CardTableEntryClosure* cl, uint worker_id); 1007 1008 // The shared block offset table array. 1009 G1BlockOffsetTable* bot() const { return _bot; } 1010 1011 // Reference Processing accessors 1012 1013 // The STW reference processor.... 1014 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 1015 1016 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; } 1017 1018 // The Concurrent Marking reference processor... 1019 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 1020 1021 size_t unused_committed_regions_in_bytes() const; 1022 1023 virtual size_t capacity() const; 1024 virtual size_t used() const; 1025 // This should be called when we're not holding the heap lock. The 1026 // result might be a bit inaccurate. 1027 size_t used_unlocked() const; 1028 size_t recalculate_used() const; 1029 1030 // These virtual functions do the actual allocation. 1031 // Some heaps may offer a contiguous region for shared non-blocking 1032 // allocation, via inlined code (by exporting the address of the top and 1033 // end fields defining the extent of the contiguous allocation region.) 1034 // But G1CollectedHeap doesn't yet support this. 1035 1036 virtual bool is_maximal_no_gc() const { 1037 return _hrm->available() == 0; 1038 } 1039 1040 // Returns whether there are any regions left in the heap for allocation. 1041 bool has_regions_left_for_allocation() const { 1042 return !is_maximal_no_gc() || num_free_regions() != 0; 1043 } 1044 1045 // The current number of regions in the heap. 1046 uint num_regions() const { return _hrm->length(); } 1047 1048 // The max number of regions in the heap. 1049 uint max_regions() const { return _hrm->max_length(); } 1050 1051 // Max number of regions that can be comitted. 1052 uint max_expandable_regions() const { return _hrm->max_expandable_length(); } 1053 1054 // The number of regions that are completely free. 1055 uint num_free_regions() const { return _hrm->num_free_regions(); } 1056 1057 // The number of regions that can be allocated into. 1058 uint num_free_or_available_regions() const { return num_free_regions() + _hrm->available(); } 1059 1060 MemoryUsage get_auxiliary_data_memory_usage() const { 1061 return _hrm->get_auxiliary_data_memory_usage(); 1062 } 1063 1064 // The number of regions that are not completely free. 1065 uint num_used_regions() const { return num_regions() - num_free_regions(); } 1066 1067 #ifdef ASSERT 1068 bool is_on_master_free_list(HeapRegion* hr) { 1069 return _hrm->is_free(hr); 1070 } 1071 #endif // ASSERT 1072 1073 inline void old_set_add(HeapRegion* hr); 1074 inline void old_set_remove(HeapRegion* hr); 1075 1076 inline void archive_set_add(HeapRegion* hr); 1077 1078 size_t non_young_capacity_bytes() { 1079 return (old_regions_count() + _archive_set.length() + humongous_regions_count()) * HeapRegion::GrainBytes; 1080 } 1081 1082 // Determine whether the given region is one that we are using as an 1083 // old GC alloc region. 1084 bool is_old_gc_alloc_region(HeapRegion* hr); 1085 1086 // Perform a collection of the heap; intended for use in implementing 1087 // "System.gc". This probably implies as full a collection as the 1088 // "CollectedHeap" supports. 1089 virtual void collect(GCCause::Cause cause); 1090 1091 // Perform a collection of the heap with the given cause; if the VM operation 1092 // fails to execute for any reason, retry only if retry_on_gc_failure is set. 1093 // Returns whether this collection actually executed. 1094 bool try_collect(GCCause::Cause cause, bool retry_on_gc_failure); 1095 1096 // True iff an evacuation has failed in the most-recent collection. 1097 bool evacuation_failed() { return _evacuation_failed; } 1098 1099 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed); 1100 void prepend_to_freelist(FreeRegionList* list); 1101 void decrement_summary_bytes(size_t bytes); 1102 1103 virtual bool is_in(const void* p) const; 1104 #ifdef ASSERT 1105 // Returns whether p is in one of the available areas of the heap. Slow but 1106 // extensive version. 1107 bool is_in_exact(const void* p) const; 1108 #endif 1109 1110 // Return "TRUE" iff the given object address is within the collection 1111 // set. Assumes that the reference points into the heap. 1112 inline bool is_in_cset(const HeapRegion *hr); 1113 inline bool is_in_cset(oop obj); 1114 inline bool is_in_cset(HeapWord* addr); 1115 1116 inline bool is_in_cset_or_humongous(const oop obj); 1117 1118 private: 1119 // This array is used for a quick test on whether a reference points into 1120 // the collection set or not. Each of the array's elements denotes whether the 1121 // corresponding region is in the collection set or not. 1122 G1HeapRegionAttrBiasedMappedArray _region_attr; 1123 1124 public: 1125 1126 inline G1HeapRegionAttr region_attr(const void* obj) const; 1127 inline G1HeapRegionAttr region_attr(uint idx) const; 1128 1129 // Return "TRUE" iff the given object address is in the reserved 1130 // region of g1. 1131 bool is_in_g1_reserved(const void* p) const { 1132 return _hrm->reserved().contains(p); 1133 } 1134 1135 // Returns a MemRegion that corresponds to the space that has been 1136 // reserved for the heap 1137 MemRegion g1_reserved() const { 1138 return _hrm->reserved(); 1139 } 1140 1141 MemRegion reserved_region() const { 1142 return _reserved; 1143 } 1144 1145 HeapWord* base() const { 1146 return _reserved.start(); 1147 } 1148 1149 bool is_in_reserved(const void* addr) const { 1150 return _reserved.contains(addr); 1151 } 1152 1153 G1HotCardCache* hot_card_cache() const { return _hot_card_cache; } 1154 1155 G1CardTable* card_table() const { 1156 return _card_table; 1157 } 1158 1159 // Iteration functions. 1160 1161 // Iterate over all objects, calling "cl.do_object" on each. 1162 virtual void object_iterate(ObjectClosure* cl); 1163 1164 virtual void safe_object_iterate(ObjectClosure* cl) { 1165 object_iterate(cl); 1166 } 1167 1168 // Iterate over heap regions, in address order, terminating the 1169 // iteration early if the "do_heap_region" method returns "true". 1170 void heap_region_iterate(HeapRegionClosure* blk) const; 1171 1172 // Return the region with the given index. It assumes the index is valid. 1173 inline HeapRegion* region_at(uint index) const; 1174 inline HeapRegion* region_at_or_null(uint index) const; 1175 1176 // Return the next region (by index) that is part of the same 1177 // humongous object that hr is part of. 1178 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const; 1179 1180 // Calculate the region index of the given address. Given address must be 1181 // within the heap. 1182 inline uint addr_to_region(HeapWord* addr) const; 1183 1184 inline HeapWord* bottom_addr_for_region(uint index) const; 1185 1186 // Two functions to iterate over the heap regions in parallel. Threads 1187 // compete using the HeapRegionClaimer to claim the regions before 1188 // applying the closure on them. 1189 // The _from_worker_offset version uses the HeapRegionClaimer and 1190 // the worker id to calculate a start offset to prevent all workers to 1191 // start from the point. 1192 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl, 1193 HeapRegionClaimer* hrclaimer, 1194 uint worker_id) const; 1195 1196 void heap_region_par_iterate_from_start(HeapRegionClosure* cl, 1197 HeapRegionClaimer* hrclaimer) const; 1198 1199 // Iterate over all regions currently in the current collection set. 1200 void collection_set_iterate_all(HeapRegionClosure* blk); 1201 1202 // Iterate over the regions in the current increment of the collection set. 1203 // Starts the iteration so that the start regions of a given worker id over the 1204 // set active_workers are evenly spread across the set of collection set regions 1205 // to be iterated. 1206 // The variant with the HeapRegionClaimer guarantees that the closure will be 1207 // applied to a particular region exactly once. 1208 void collection_set_iterate_increment_from(HeapRegionClosure *blk, uint worker_id) { 1209 collection_set_iterate_increment_from(blk, NULL, worker_id); 1210 } 1211 void collection_set_iterate_increment_from(HeapRegionClosure *blk, HeapRegionClaimer* hr_claimer, uint worker_id); 1212 1213 // Returns the HeapRegion that contains addr. addr must not be NULL. 1214 template <class T> 1215 inline HeapRegion* heap_region_containing(const T addr) const; 1216 1217 // Returns the HeapRegion that contains addr, or NULL if that is an uncommitted 1218 // region. addr must not be NULL. 1219 template <class T> 1220 inline HeapRegion* heap_region_containing_or_null(const T addr) const; 1221 1222 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1223 // each address in the (reserved) heap is a member of exactly 1224 // one block. The defining characteristic of a block is that it is 1225 // possible to find its size, and thus to progress forward to the next 1226 // block. (Blocks may be of different sizes.) Thus, blocks may 1227 // represent Java objects, or they might be free blocks in a 1228 // free-list-based heap (or subheap), as long as the two kinds are 1229 // distinguishable and the size of each is determinable. 1230 1231 // Returns the address of the start of the "block" that contains the 1232 // address "addr". We say "blocks" instead of "object" since some heaps 1233 // may not pack objects densely; a chunk may either be an object or a 1234 // non-object. 1235 HeapWord* block_start(const void* addr) const; 1236 1237 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1238 // the block is an object. 1239 bool block_is_obj(const HeapWord* addr) const; 1240 1241 // Section on thread-local allocation buffers (TLABs) 1242 // See CollectedHeap for semantics. 1243 1244 bool supports_tlab_allocation() const; 1245 size_t tlab_capacity(Thread* ignored) const; 1246 size_t tlab_used(Thread* ignored) const; 1247 size_t max_tlab_size() const; 1248 size_t unsafe_max_tlab_alloc(Thread* ignored) const; 1249 1250 inline bool is_in_young(const oop obj); 1251 1252 // Returns "true" iff the given word_size is "very large". 1253 static bool is_humongous(size_t word_size) { 1254 // Note this has to be strictly greater-than as the TLABs 1255 // are capped at the humongous threshold and we want to 1256 // ensure that we don't try to allocate a TLAB as 1257 // humongous and that we don't allocate a humongous 1258 // object in a TLAB. 1259 return word_size > _humongous_object_threshold_in_words; 1260 } 1261 1262 // Returns the humongous threshold for a specific region size 1263 static size_t humongous_threshold_for(size_t region_size) { 1264 return (region_size / 2); 1265 } 1266 1267 // Returns the number of regions the humongous object of the given word size 1268 // requires. 1269 static size_t humongous_obj_size_in_regions(size_t word_size); 1270 1271 // Print the maximum heap capacity. 1272 virtual size_t max_capacity() const; 1273 1274 // Return the size of reserved memory. Returns different value than max_capacity() when AllocateOldGenAt is used. 1275 virtual size_t max_reserved_capacity() const; 1276 1277 virtual jlong millis_since_last_gc(); 1278 1279 1280 // Convenience function to be used in situations where the heap type can be 1281 // asserted to be this type. 1282 static G1CollectedHeap* heap(); 1283 1284 void set_region_short_lived_locked(HeapRegion* hr); 1285 // add appropriate methods for any other surv rate groups 1286 1287 const G1SurvivorRegions* survivor() const { return &_survivor; } 1288 1289 uint eden_regions_count() const { return _eden.length(); } 1290 uint eden_regions_count(uint node_index) const { return _eden.regions_on_node(node_index); } 1291 uint survivor_regions_count() const { return _survivor.length(); } 1292 uint survivor_regions_count(uint node_index) const { return _survivor.regions_on_node(node_index); } 1293 size_t eden_regions_used_bytes() const { return _eden.used_bytes(); } 1294 size_t survivor_regions_used_bytes() const { return _survivor.used_bytes(); } 1295 uint young_regions_count() const { return _eden.length() + _survivor.length(); } 1296 uint old_regions_count() const { return _old_set.length(); } 1297 uint archive_regions_count() const { return _archive_set.length(); } 1298 uint humongous_regions_count() const { return _humongous_set.length(); } 1299 1300 #ifdef ASSERT 1301 bool check_young_list_empty(); 1302 #endif 1303 1304 // *** Stuff related to concurrent marking. It's not clear to me that so 1305 // many of these need to be public. 1306 1307 // The functions below are helper functions that a subclass of 1308 // "CollectedHeap" can use in the implementation of its virtual 1309 // functions. 1310 // This performs a concurrent marking of the live objects in a 1311 // bitmap off to the side. 1312 void do_concurrent_mark(); 1313 1314 bool is_marked_next(oop obj) const; 1315 1316 // Determine if an object is dead, given the object and also 1317 // the region to which the object belongs. An object is dead 1318 // iff a) it was not allocated since the last mark, b) it 1319 // is not marked, and c) it is not in an archive region. 1320 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1321 return 1322 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) && 1323 !hr->is_archive(); 1324 } 1325 1326 // This function returns true when an object has been 1327 // around since the previous marking and hasn't yet 1328 // been marked during this marking, and is not in an archive region. 1329 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1330 return 1331 !hr->obj_allocated_since_next_marking(obj) && 1332 !is_marked_next(obj) && 1333 !hr->is_archive(); 1334 } 1335 1336 // Determine if an object is dead, given only the object itself. 1337 // This will find the region to which the object belongs and 1338 // then call the region version of the same function. 1339 1340 // Added if it is NULL it isn't dead. 1341 1342 inline bool is_obj_dead(const oop obj) const; 1343 1344 inline bool is_obj_ill(const oop obj) const; 1345 1346 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const; 1347 inline bool is_obj_dead_full(const oop obj) const; 1348 1349 G1ConcurrentMark* concurrent_mark() const { return _cm; } 1350 1351 // Refinement 1352 1353 G1ConcurrentRefine* concurrent_refine() const { return _cr; } 1354 1355 // Optimized nmethod scanning support routines 1356 1357 // Register the given nmethod with the G1 heap. 1358 virtual void register_nmethod(nmethod* nm); 1359 1360 // Unregister the given nmethod from the G1 heap. 1361 virtual void unregister_nmethod(nmethod* nm); 1362 1363 // No nmethod flushing needed. 1364 virtual void flush_nmethod(nmethod* nm) {} 1365 1366 // No nmethod verification implemented. 1367 virtual void verify_nmethod(nmethod* nm) {} 1368 1369 // Free up superfluous code root memory. 1370 void purge_code_root_memory(); 1371 1372 // Rebuild the strong code root lists for each region 1373 // after a full GC. 1374 void rebuild_strong_code_roots(); 1375 1376 // Partial cleaning of VM internal data structures. 1377 void string_dedup_cleaning(BoolObjectClosure* is_alive, 1378 OopClosure* keep_alive, 1379 G1GCPhaseTimes* phase_times = NULL); 1380 1381 // Performs cleaning of data structures after class unloading. 1382 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred); 1383 1384 // Redirty logged cards in the refinement queue. 1385 void redirty_logged_cards(G1RedirtyCardsQueueSet* rdcqs); 1386 1387 // Verification 1388 1389 // Deduplicate the string 1390 virtual void deduplicate_string(oop str); 1391 1392 // Perform any cleanup actions necessary before allowing a verification. 1393 virtual void prepare_for_verify(); 1394 1395 // Perform verification. 1396 1397 // vo == UsePrevMarking -> use "prev" marking information, 1398 // vo == UseNextMarking -> use "next" marking information 1399 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS 1400 // 1401 // NOTE: Only the "prev" marking information is guaranteed to be 1402 // consistent most of the time, so most calls to this should use 1403 // vo == UsePrevMarking. 1404 // Currently, there is only one case where this is called with 1405 // vo == UseNextMarking, which is to verify the "next" marking 1406 // information at the end of remark. 1407 // Currently there is only one place where this is called with 1408 // vo == UseFullMarking, which is to verify the marking during a 1409 // full GC. 1410 void verify(VerifyOption vo); 1411 1412 // WhiteBox testing support. 1413 virtual bool supports_concurrent_phase_control() const; 1414 virtual bool request_concurrent_phase(const char* phase); 1415 bool is_heterogeneous_heap() const; 1416 1417 virtual WorkGang* get_safepoint_workers() { return _workers; } 1418 1419 // The methods below are here for convenience and dispatch the 1420 // appropriate method depending on value of the given VerifyOption 1421 // parameter. The values for that parameter, and their meanings, 1422 // are the same as those above. 1423 1424 bool is_obj_dead_cond(const oop obj, 1425 const HeapRegion* hr, 1426 const VerifyOption vo) const; 1427 1428 bool is_obj_dead_cond(const oop obj, 1429 const VerifyOption vo) const; 1430 1431 G1HeapSummary create_g1_heap_summary(); 1432 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats); 1433 1434 // Printing 1435 private: 1436 void print_heap_regions() const; 1437 void print_regions_on(outputStream* st) const; 1438 1439 public: 1440 virtual void print_on(outputStream* st) const; 1441 virtual void print_extended_on(outputStream* st) const; 1442 virtual void print_on_error(outputStream* st) const; 1443 1444 virtual void print_gc_threads_on(outputStream* st) const; 1445 virtual void gc_threads_do(ThreadClosure* tc) const; 1446 1447 // Override 1448 void print_tracing_info() const; 1449 1450 // The following two methods are helpful for debugging RSet issues. 1451 void print_cset_rsets() PRODUCT_RETURN; 1452 void print_all_rsets() PRODUCT_RETURN; 1453 1454 // Used to print information about locations in the hs_err file. 1455 virtual bool print_location(outputStream* st, void* addr) const; 1456 1457 size_t pending_card_num(); 1458 }; 1459 1460 class G1ParEvacuateFollowersClosure : public VoidClosure { 1461 private: 1462 double _start_term; 1463 double _term_time; 1464 size_t _term_attempts; 1465 1466 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); } 1467 void end_term_time() { _term_time += (os::elapsedTime() - _start_term); } 1468 protected: 1469 G1CollectedHeap* _g1h; 1470 G1ParScanThreadState* _par_scan_state; 1471 RefToScanQueueSet* _queues; 1472 ParallelTaskTerminator* _terminator; 1473 G1GCPhaseTimes::GCParPhases _phase; 1474 1475 G1ParScanThreadState* par_scan_state() { return _par_scan_state; } 1476 RefToScanQueueSet* queues() { return _queues; } 1477 ParallelTaskTerminator* terminator() { return _terminator; } 1478 1479 public: 1480 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h, 1481 G1ParScanThreadState* par_scan_state, 1482 RefToScanQueueSet* queues, 1483 ParallelTaskTerminator* terminator, 1484 G1GCPhaseTimes::GCParPhases phase) 1485 : _start_term(0.0), _term_time(0.0), _term_attempts(0), 1486 _g1h(g1h), _par_scan_state(par_scan_state), 1487 _queues(queues), _terminator(terminator), _phase(phase) {} 1488 1489 void do_void(); 1490 1491 double term_time() const { return _term_time; } 1492 size_t term_attempts() const { return _term_attempts; } 1493 1494 private: 1495 inline bool offer_termination(); 1496 }; 1497 1498 #endif // SHARE_GC_G1_G1COLLECTEDHEAP_HPP