1 /* 2 * Copyright (c) 2001, 2018, 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_VM_GC_G1_G1COLLECTEDHEAP_HPP 26 #define SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP 27 28 #include "gc/g1/evacuationInfo.hpp" 29 #include "gc/g1/g1BarrierSet.hpp" 30 #include "gc/g1/g1BiasedArray.hpp" 31 #include "gc/g1/g1CardTable.hpp" 32 #include "gc/g1/g1CollectionSet.hpp" 33 #include "gc/g1/g1CollectorState.hpp" 34 #include "gc/g1/g1ConcurrentMark.hpp" 35 #include "gc/g1/g1EdenRegions.hpp" 36 #include "gc/g1/g1EvacFailure.hpp" 37 #include "gc/g1/g1EvacStats.hpp" 38 #include "gc/g1/g1HeapTransition.hpp" 39 #include "gc/g1/g1HeapVerifier.hpp" 40 #include "gc/g1/g1HRPrinter.hpp" 41 #include "gc/g1/g1InCSetState.hpp" 42 #include "gc/g1/g1MonitoringSupport.hpp" 43 #include "gc/g1/g1SurvivorRegions.hpp" 44 #include "gc/g1/g1YCTypes.hpp" 45 #include "gc/g1/heapRegionManager.hpp" 46 #include "gc/g1/heapRegionSet.hpp" 47 #include "gc/shared/barrierSet.hpp" 48 #include "gc/shared/collectedHeap.hpp" 49 #include "gc/shared/gcHeapSummary.hpp" 50 #include "gc/shared/plab.hpp" 51 #include "gc/shared/preservedMarks.hpp" 52 #include "gc/shared/softRefPolicy.hpp" 53 #include "memory/memRegion.hpp" 54 #include "services/memoryManager.hpp" 55 #include "utilities/stack.hpp" 56 57 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot. 58 // It uses the "Garbage First" heap organization and algorithm, which 59 // may combine concurrent marking with parallel, incremental compaction of 60 // heap subsets that will yield large amounts of garbage. 61 62 // Forward declarations 63 class HeapRegion; 64 class HRRSCleanupTask; 65 class GenerationSpec; 66 class G1ParScanThreadState; 67 class G1ParScanThreadStateSet; 68 class G1ParScanThreadState; 69 class MemoryPool; 70 class ObjectClosure; 71 class SpaceClosure; 72 class CompactibleSpaceClosure; 73 class Space; 74 class G1CollectionSet; 75 class G1CollectorPolicy; 76 class G1Policy; 77 class G1HotCardCache; 78 class G1RemSet; 79 class G1YoungRemSetSamplingThread; 80 class HeapRegionRemSetIterator; 81 class G1ConcurrentMark; 82 class G1ConcurrentMarkThread; 83 class G1ConcurrentRefine; 84 class GenerationCounters; 85 class STWGCTimer; 86 class G1NewTracer; 87 class EvacuationFailedInfo; 88 class nmethod; 89 class Ticks; 90 class WorkGang; 91 class G1Allocator; 92 class G1ArchiveAllocator; 93 class G1FullGCScope; 94 class G1HeapVerifier; 95 class G1HeapSizingPolicy; 96 class G1HeapSummary; 97 class G1EvacSummary; 98 99 typedef OverflowTaskQueue<StarTask, mtGC> RefToScanQueue; 100 typedef GenericTaskQueueSet<RefToScanQueue, mtGC> RefToScanQueueSet; 101 102 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() ) 103 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion ) 104 105 // The G1 STW is alive closure. 106 // An instance is embedded into the G1CH and used as the 107 // (optional) _is_alive_non_header closure in the STW 108 // reference processor. It is also extensively used during 109 // reference processing during STW evacuation pauses. 110 class G1STWIsAliveClosure: public BoolObjectClosure { 111 G1CollectedHeap* _g1; 112 public: 113 G1STWIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) {} 114 bool do_object_b(oop p); 115 }; 116 117 class G1RegionMappingChangedListener : public G1MappingChangedListener { 118 private: 119 void reset_from_card_cache(uint start_idx, size_t num_regions); 120 public: 121 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 122 }; 123 124 class G1CollectedHeap : public CollectedHeap { 125 friend class G1FreeCollectionSetTask; 126 friend class VM_CollectForMetadataAllocation; 127 friend class VM_G1CollectForAllocation; 128 friend class VM_G1CollectFull; 129 friend class VMStructs; 130 friend class MutatorAllocRegion; 131 friend class G1FullCollector; 132 friend class G1GCAllocRegion; 133 friend class G1HeapVerifier; 134 135 // Closures used in implementation. 136 friend class G1ParScanThreadState; 137 friend class G1ParScanThreadStateSet; 138 friend class G1ParTask; 139 friend class G1PLABAllocator; 140 friend class G1PrepareCompactClosure; 141 142 // Other related classes. 143 friend class HeapRegionClaimer; 144 145 // Testing classes. 146 friend class G1CheckCSetFastTableClosure; 147 148 private: 149 G1YoungRemSetSamplingThread* _young_gen_sampling_thread; 150 151 WorkGang* _workers; 152 G1CollectorPolicy* _collector_policy; 153 G1CardTable* _card_table; 154 155 SoftRefPolicy _soft_ref_policy; 156 157 GCMemoryManager _memory_manager; 158 GCMemoryManager _full_gc_memory_manager; 159 160 MemoryPool* _eden_pool; 161 MemoryPool* _survivor_pool; 162 MemoryPool* _old_pool; 163 164 static size_t _humongous_object_threshold_in_words; 165 166 // It keeps track of the old regions. 167 HeapRegionSet _old_set; 168 169 // It keeps track of the humongous regions. 170 HeapRegionSet _humongous_set; 171 172 virtual void initialize_serviceability(); 173 174 void eagerly_reclaim_humongous_regions(); 175 // Start a new incremental collection set for the next pause. 176 void start_new_collection_set(); 177 178 // The number of regions we could create by expansion. 179 uint _expansion_regions; 180 181 // The block offset table for the G1 heap. 182 G1BlockOffsetTable* _bot; 183 184 // Tears down the region sets / lists so that they are empty and the 185 // regions on the heap do not belong to a region set / list. The 186 // only exception is the humongous set which we leave unaltered. If 187 // free_list_only is true, it will only tear down the master free 188 // list. It is called before a Full GC (free_list_only == false) or 189 // before heap shrinking (free_list_only == true). 190 void tear_down_region_sets(bool free_list_only); 191 192 // Rebuilds the region sets / lists so that they are repopulated to 193 // reflect the contents of the heap. The only exception is the 194 // humongous set which was not torn down in the first place. If 195 // free_list_only is true, it will only rebuild the master free 196 // list. It is called after a Full GC (free_list_only == false) or 197 // after heap shrinking (free_list_only == true). 198 void rebuild_region_sets(bool free_list_only); 199 200 // Callback for region mapping changed events. 201 G1RegionMappingChangedListener _listener; 202 203 // The sequence of all heap regions in the heap. 204 HeapRegionManager _hrm; 205 206 // Manages all allocations with regions except humongous object allocations. 207 G1Allocator* _allocator; 208 209 // Manages all heap verification. 210 G1HeapVerifier* _verifier; 211 212 // Outside of GC pauses, the number of bytes used in all regions other 213 // than the current allocation region(s). 214 size_t _summary_bytes_used; 215 216 void increase_used(size_t bytes); 217 void decrease_used(size_t bytes); 218 219 void set_used(size_t bytes); 220 221 // Class that handles archive allocation ranges. 222 G1ArchiveAllocator* _archive_allocator; 223 224 // GC allocation statistics policy for survivors. 225 G1EvacStats _survivor_evac_stats; 226 227 // GC allocation statistics policy for tenured objects. 228 G1EvacStats _old_evac_stats; 229 230 // It specifies whether we should attempt to expand the heap after a 231 // region allocation failure. If heap expansion fails we set this to 232 // false so that we don't re-attempt the heap expansion (it's likely 233 // that subsequent expansion attempts will also fail if one fails). 234 // Currently, it is only consulted during GC and it's reset at the 235 // start of each GC. 236 bool _expand_heap_after_alloc_failure; 237 238 // Helper for monitoring and management support. 239 G1MonitoringSupport* _g1mm; 240 241 // Records whether the region at the given index is (still) a 242 // candidate for eager reclaim. Only valid for humongous start 243 // regions; other regions have unspecified values. Humongous start 244 // regions are initialized at start of collection pause, with 245 // candidates removed from the set as they are found reachable from 246 // roots or the young generation. 247 class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> { 248 protected: 249 bool default_value() const { return false; } 250 public: 251 void clear() { G1BiasedMappedArray<bool>::clear(); } 252 void set_candidate(uint region, bool value) { 253 set_by_index(region, value); 254 } 255 bool is_candidate(uint region) { 256 return get_by_index(region); 257 } 258 }; 259 260 HumongousReclaimCandidates _humongous_reclaim_candidates; 261 // Stores whether during humongous object registration we found candidate regions. 262 // If not, we can skip a few steps. 263 bool _has_humongous_reclaim_candidates; 264 265 G1HRPrinter _hr_printer; 266 267 // It decides whether an explicit GC should start a concurrent cycle 268 // instead of doing a STW GC. Currently, a concurrent cycle is 269 // explicitly started if: 270 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or 271 // (b) cause == _g1_humongous_allocation 272 // (c) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent. 273 // (d) cause == _dcmd_gc_run and +ExplicitGCInvokesConcurrent. 274 // (e) cause == _wb_conc_mark 275 bool should_do_concurrent_full_gc(GCCause::Cause cause); 276 277 // indicates whether we are in young or mixed GC mode 278 G1CollectorState _collector_state; 279 280 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 281 // concurrent cycles) we have started. 282 volatile uint _old_marking_cycles_started; 283 284 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 285 // concurrent cycles) we have completed. 286 volatile uint _old_marking_cycles_completed; 287 288 // This is a non-product method that is helpful for testing. It is 289 // called at the end of a GC and artificially expands the heap by 290 // allocating a number of dead regions. This way we can induce very 291 // frequent marking cycles and stress the cleanup / concurrent 292 // cleanup code more (as all the regions that will be allocated by 293 // this method will be found dead by the marking cycle). 294 void allocate_dummy_regions() PRODUCT_RETURN; 295 296 // If the HR printer is active, dump the state of the regions in the 297 // heap after a compaction. 298 void print_hrm_post_compaction(); 299 300 // Create a memory mapper for auxiliary data structures of the given size and 301 // translation factor. 302 static G1RegionToSpaceMapper* create_aux_memory_mapper(const char* description, 303 size_t size, 304 size_t translation_factor); 305 306 void trace_heap(GCWhen::Type when, const GCTracer* tracer); 307 308 // These are macros so that, if the assert fires, we get the correct 309 // line number, file, etc. 310 311 #define heap_locking_asserts_params(_extra_message_) \ 312 "%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 313 (_extra_message_), \ 314 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 315 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 316 BOOL_TO_STR(Thread::current()->is_VM_thread()) 317 318 #define assert_heap_locked() \ 319 do { \ 320 assert(Heap_lock->owned_by_self(), \ 321 heap_locking_asserts_params("should be holding the Heap_lock")); \ 322 } while (0) 323 324 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 325 do { \ 326 assert(Heap_lock->owned_by_self() || \ 327 (SafepointSynchronize::is_at_safepoint() && \ 328 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 329 heap_locking_asserts_params("should be holding the Heap_lock or " \ 330 "should be at a safepoint")); \ 331 } while (0) 332 333 #define assert_heap_locked_and_not_at_safepoint() \ 334 do { \ 335 assert(Heap_lock->owned_by_self() && \ 336 !SafepointSynchronize::is_at_safepoint(), \ 337 heap_locking_asserts_params("should be holding the Heap_lock and " \ 338 "should not be at a safepoint")); \ 339 } while (0) 340 341 #define assert_heap_not_locked() \ 342 do { \ 343 assert(!Heap_lock->owned_by_self(), \ 344 heap_locking_asserts_params("should not be holding the Heap_lock")); \ 345 } while (0) 346 347 #define assert_heap_not_locked_and_not_at_safepoint() \ 348 do { \ 349 assert(!Heap_lock->owned_by_self() && \ 350 !SafepointSynchronize::is_at_safepoint(), \ 351 heap_locking_asserts_params("should not be holding the Heap_lock and " \ 352 "should not be at a safepoint")); \ 353 } while (0) 354 355 #define assert_at_safepoint_on_vm_thread() \ 356 do { \ 357 assert_at_safepoint(); \ 358 assert(Thread::current_or_null() != NULL, "no current thread"); \ 359 assert(Thread::current()->is_VM_thread(), "current thread is not VM thread"); \ 360 } while (0) 361 362 // The young region list. 363 G1EdenRegions _eden; 364 G1SurvivorRegions _survivor; 365 366 STWGCTimer* _gc_timer_stw; 367 368 G1NewTracer* _gc_tracer_stw; 369 370 // The current policy object for the collector. 371 G1Policy* _g1_policy; 372 G1HeapSizingPolicy* _heap_sizing_policy; 373 374 G1CollectionSet _collection_set; 375 376 // Try to allocate a single non-humongous HeapRegion sufficient for 377 // an allocation of the given word_size. If do_expand is true, 378 // attempt to expand the heap if necessary to satisfy the allocation 379 // request. If the region is to be used as an old region or for a 380 // humongous object, set is_old to true. If not, to false. 381 HeapRegion* new_region(size_t word_size, bool is_old, bool do_expand); 382 383 // Initialize a contiguous set of free regions of length num_regions 384 // and starting at index first so that they appear as a single 385 // humongous region. 386 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 387 uint num_regions, 388 size_t word_size); 389 390 // Attempt to allocate a humongous object of the given size. Return 391 // NULL if unsuccessful. 392 HeapWord* humongous_obj_allocate(size_t word_size); 393 394 // The following two methods, allocate_new_tlab() and 395 // mem_allocate(), are the two main entry points from the runtime 396 // into the G1's allocation routines. They have the following 397 // assumptions: 398 // 399 // * They should both be called outside safepoints. 400 // 401 // * They should both be called without holding the Heap_lock. 402 // 403 // * All allocation requests for new TLABs should go to 404 // allocate_new_tlab(). 405 // 406 // * All non-TLAB allocation requests should go to mem_allocate(). 407 // 408 // * If either call cannot satisfy the allocation request using the 409 // current allocating region, they will try to get a new one. If 410 // this fails, they will attempt to do an evacuation pause and 411 // retry the allocation. 412 // 413 // * If all allocation attempts fail, even after trying to schedule 414 // an evacuation pause, allocate_new_tlab() will return NULL, 415 // whereas mem_allocate() will attempt a heap expansion and/or 416 // schedule a Full GC. 417 // 418 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 419 // should never be called with word_size being humongous. All 420 // humongous allocation requests should go to mem_allocate() which 421 // will satisfy them with a special path. 422 423 virtual HeapWord* allocate_new_tlab(size_t word_size); 424 425 virtual HeapWord* mem_allocate(size_t word_size, 426 bool* gc_overhead_limit_was_exceeded); 427 428 // First-level mutator allocation attempt: try to allocate out of 429 // the mutator alloc region without taking the Heap_lock. This 430 // should only be used for non-humongous allocations. 431 inline HeapWord* attempt_allocation(size_t word_size); 432 433 // Second-level mutator allocation attempt: take the Heap_lock and 434 // retry the allocation attempt, potentially scheduling a GC 435 // pause. This should only be used for non-humongous allocations. 436 HeapWord* attempt_allocation_slow(size_t word_size); 437 438 // Takes the Heap_lock and attempts a humongous allocation. It can 439 // potentially schedule a GC pause. 440 HeapWord* attempt_allocation_humongous(size_t word_size); 441 442 // Allocation attempt that should be called during safepoints (e.g., 443 // at the end of a successful GC). expect_null_mutator_alloc_region 444 // specifies whether the mutator alloc region is expected to be NULL 445 // or not. 446 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 447 bool expect_null_mutator_alloc_region); 448 449 // These methods are the "callbacks" from the G1AllocRegion class. 450 451 // For mutator alloc regions. 452 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force); 453 void retire_mutator_alloc_region(HeapRegion* alloc_region, 454 size_t allocated_bytes); 455 456 // For GC alloc regions. 457 bool has_more_regions(InCSetState dest); 458 HeapRegion* new_gc_alloc_region(size_t word_size, InCSetState dest); 459 void retire_gc_alloc_region(HeapRegion* alloc_region, 460 size_t allocated_bytes, InCSetState dest); 461 462 // - if explicit_gc is true, the GC is for a System.gc() etc, 463 // otherwise it's for a failed allocation. 464 // - if clear_all_soft_refs is true, all soft references should be 465 // cleared during the GC. 466 // - it returns false if it is unable to do the collection due to the 467 // GC locker being active, true otherwise. 468 bool do_full_collection(bool explicit_gc, 469 bool clear_all_soft_refs); 470 471 // Callback from VM_G1CollectFull operation, or collect_as_vm_thread. 472 virtual void do_full_collection(bool clear_all_soft_refs); 473 474 // Resize the heap if necessary after a full collection. 475 void resize_if_necessary_after_full_collection(); 476 477 // Callback from VM_G1CollectForAllocation operation. 478 // This function does everything necessary/possible to satisfy a 479 // failed allocation request (including collection, expansion, etc.) 480 HeapWord* satisfy_failed_allocation(size_t word_size, 481 bool* succeeded); 482 // Internal helpers used during full GC to split it up to 483 // increase readability. 484 void abort_concurrent_cycle(); 485 void verify_before_full_collection(bool explicit_gc); 486 void prepare_heap_for_full_collection(); 487 void prepare_heap_for_mutators(); 488 void abort_refinement(); 489 void verify_after_full_collection(); 490 void print_heap_after_full_collection(G1HeapTransition* heap_transition); 491 492 // Helper method for satisfy_failed_allocation() 493 HeapWord* satisfy_failed_allocation_helper(size_t word_size, 494 bool do_gc, 495 bool clear_all_soft_refs, 496 bool expect_null_mutator_alloc_region, 497 bool* gc_succeeded); 498 499 // Attempting to expand the heap sufficiently 500 // to support an allocation of the given "word_size". If 501 // successful, perform the allocation and return the address of the 502 // allocated block, or else "NULL". 503 HeapWord* expand_and_allocate(size_t word_size); 504 505 // Preserve any referents discovered by concurrent marking that have not yet been 506 // copied by the STW pause. 507 void preserve_cm_referents(G1ParScanThreadStateSet* per_thread_states); 508 // Process any reference objects discovered during 509 // an incremental evacuation pause. 510 void process_discovered_references(G1ParScanThreadStateSet* per_thread_states); 511 512 // Enqueue any remaining discovered references 513 // after processing. 514 void enqueue_discovered_references(G1ParScanThreadStateSet* per_thread_states); 515 516 // Merges the information gathered on a per-thread basis for all worker threads 517 // during GC into global variables. 518 void merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states); 519 public: 520 G1YoungRemSetSamplingThread* sampling_thread() const { return _young_gen_sampling_thread; } 521 522 WorkGang* workers() const { return _workers; } 523 524 G1Allocator* allocator() { 525 return _allocator; 526 } 527 528 G1HeapVerifier* verifier() { 529 return _verifier; 530 } 531 532 G1MonitoringSupport* g1mm() { 533 assert(_g1mm != NULL, "should have been initialized"); 534 return _g1mm; 535 } 536 537 // Expand the garbage-first heap by at least the given size (in bytes!). 538 // Returns true if the heap was expanded by the requested amount; 539 // false otherwise. 540 // (Rounds up to a HeapRegion boundary.) 541 bool expand(size_t expand_bytes, WorkGang* pretouch_workers = NULL, double* expand_time_ms = NULL); 542 543 // Returns the PLAB statistics for a given destination. 544 inline G1EvacStats* alloc_buffer_stats(InCSetState dest); 545 546 // Determines PLAB size for a given destination. 547 inline size_t desired_plab_sz(InCSetState dest); 548 549 // Do anything common to GC's. 550 void gc_prologue(bool full); 551 void gc_epilogue(bool full); 552 553 // Does the given region fulfill remembered set based eager reclaim candidate requirements? 554 bool is_potential_eager_reclaim_candidate(HeapRegion* r) const; 555 556 // Modify the reclaim candidate set and test for presence. 557 // These are only valid for starts_humongous regions. 558 inline void set_humongous_reclaim_candidate(uint region, bool value); 559 inline bool is_humongous_reclaim_candidate(uint region); 560 561 // Remove from the reclaim candidate set. Also remove from the 562 // collection set so that later encounters avoid the slow path. 563 inline void set_humongous_is_live(oop obj); 564 565 // Register the given region to be part of the collection set. 566 inline void register_humongous_region_with_cset(uint index); 567 // Register regions with humongous objects (actually on the start region) in 568 // the in_cset_fast_test table. 569 void register_humongous_regions_with_cset(); 570 // We register a region with the fast "in collection set" test. We 571 // simply set to true the array slot corresponding to this region. 572 void register_young_region_with_cset(HeapRegion* r) { 573 _in_cset_fast_test.set_in_young(r->hrm_index()); 574 } 575 void register_old_region_with_cset(HeapRegion* r) { 576 _in_cset_fast_test.set_in_old(r->hrm_index()); 577 } 578 void clear_in_cset(const HeapRegion* hr) { 579 _in_cset_fast_test.clear(hr); 580 } 581 582 void clear_cset_fast_test() { 583 _in_cset_fast_test.clear(); 584 } 585 586 bool is_user_requested_concurrent_full_gc(GCCause::Cause cause); 587 588 // This is called at the start of either a concurrent cycle or a Full 589 // GC to update the number of old marking cycles started. 590 void increment_old_marking_cycles_started(); 591 592 // This is called at the end of either a concurrent cycle or a Full 593 // GC to update the number of old marking cycles completed. Those two 594 // can happen in a nested fashion, i.e., we start a concurrent 595 // cycle, a Full GC happens half-way through it which ends first, 596 // and then the cycle notices that a Full GC happened and ends 597 // too. The concurrent parameter is a boolean to help us do a bit 598 // tighter consistency checking in the method. If concurrent is 599 // false, the caller is the inner caller in the nesting (i.e., the 600 // Full GC). If concurrent is true, the caller is the outer caller 601 // in this nesting (i.e., the concurrent cycle). Further nesting is 602 // not currently supported. The end of this call also notifies 603 // the FullGCCount_lock in case a Java thread is waiting for a full 604 // GC to happen (e.g., it called System.gc() with 605 // +ExplicitGCInvokesConcurrent). 606 void increment_old_marking_cycles_completed(bool concurrent); 607 608 uint old_marking_cycles_completed() { 609 return _old_marking_cycles_completed; 610 } 611 612 G1HRPrinter* hr_printer() { return &_hr_printer; } 613 614 // Allocates a new heap region instance. 615 HeapRegion* new_heap_region(uint hrs_index, MemRegion mr); 616 617 // Allocate the highest free region in the reserved heap. This will commit 618 // regions as necessary. 619 HeapRegion* alloc_highest_free_region(); 620 621 // Frees a non-humongous region by initializing its contents and 622 // adding it to the free list that's passed as a parameter (this is 623 // usually a local list which will be appended to the master free 624 // list later). The used bytes of freed regions are accumulated in 625 // pre_used. If skip_remset is true, the region's RSet will not be freed 626 // up. If skip_hot_card_cache is true, the region's hot card cache will not 627 // be freed up. The assumption is that this will be done later. 628 // The locked parameter indicates if the caller has already taken 629 // care of proper synchronization. This may allow some optimizations. 630 void free_region(HeapRegion* hr, 631 FreeRegionList* free_list, 632 bool skip_remset, 633 bool skip_hot_card_cache = false, 634 bool locked = false); 635 636 // It dirties the cards that cover the block so that the post 637 // write barrier never queues anything when updating objects on this 638 // block. It is assumed (and in fact we assert) that the block 639 // belongs to a young region. 640 inline void dirty_young_block(HeapWord* start, size_t word_size); 641 642 // Frees a humongous region by collapsing it into individual regions 643 // and calling free_region() for each of them. The freed regions 644 // will be added to the free list that's passed as a parameter (this 645 // is usually a local list which will be appended to the master free 646 // list later). 647 // The method assumes that only a single thread is ever calling 648 // this for a particular region at once. 649 void free_humongous_region(HeapRegion* hr, 650 FreeRegionList* free_list); 651 652 // Facility for allocating in 'archive' regions in high heap memory and 653 // recording the allocated ranges. These should all be called from the 654 // VM thread at safepoints, without the heap lock held. They can be used 655 // to create and archive a set of heap regions which can be mapped at the 656 // same fixed addresses in a subsequent JVM invocation. 657 void begin_archive_alloc_range(bool open = false); 658 659 // Check if the requested size would be too large for an archive allocation. 660 bool is_archive_alloc_too_large(size_t word_size); 661 662 // Allocate memory of the requested size from the archive region. This will 663 // return NULL if the size is too large or if no memory is available. It 664 // does not trigger a garbage collection. 665 HeapWord* archive_mem_allocate(size_t word_size); 666 667 // Optionally aligns the end address and returns the allocated ranges in 668 // an array of MemRegions in order of ascending addresses. 669 void end_archive_alloc_range(GrowableArray<MemRegion>* ranges, 670 size_t end_alignment_in_bytes = 0); 671 672 // Facility for allocating a fixed range within the heap and marking 673 // the containing regions as 'archive'. For use at JVM init time, when the 674 // caller may mmap archived heap data at the specified range(s). 675 // Verify that the MemRegions specified in the argument array are within the 676 // reserved heap. 677 bool check_archive_addresses(MemRegion* range, size_t count); 678 679 // Commit the appropriate G1 regions containing the specified MemRegions 680 // and mark them as 'archive' regions. The regions in the array must be 681 // non-overlapping and in order of ascending address. 682 bool alloc_archive_regions(MemRegion* range, size_t count, bool open); 683 684 // Insert any required filler objects in the G1 regions around the specified 685 // ranges to make the regions parseable. This must be called after 686 // alloc_archive_regions, and after class loading has occurred. 687 void fill_archive_regions(MemRegion* range, size_t count); 688 689 // For each of the specified MemRegions, uncommit the containing G1 regions 690 // which had been allocated by alloc_archive_regions. This should be called 691 // rather than fill_archive_regions at JVM init time if the archive file 692 // mapping failed, with the same non-overlapping and sorted MemRegion array. 693 void dealloc_archive_regions(MemRegion* range, size_t count); 694 695 private: 696 697 // Shrink the garbage-first heap by at most the given size (in bytes!). 698 // (Rounds down to a HeapRegion boundary.) 699 void shrink(size_t expand_bytes); 700 void shrink_helper(size_t expand_bytes); 701 702 #if TASKQUEUE_STATS 703 static void print_taskqueue_stats_hdr(outputStream* const st); 704 void print_taskqueue_stats() const; 705 void reset_taskqueue_stats(); 706 #endif // TASKQUEUE_STATS 707 708 // Schedule the VM operation that will do an evacuation pause to 709 // satisfy an allocation request of word_size. *succeeded will 710 // return whether the VM operation was successful (it did do an 711 // evacuation pause) or not (another thread beat us to it or the GC 712 // locker was active). Given that we should not be holding the 713 // Heap_lock when we enter this method, we will pass the 714 // gc_count_before (i.e., total_collections()) as a parameter since 715 // it has to be read while holding the Heap_lock. Currently, both 716 // methods that call do_collection_pause() release the Heap_lock 717 // before the call, so it's easy to read gc_count_before just before. 718 HeapWord* do_collection_pause(size_t word_size, 719 uint gc_count_before, 720 bool* succeeded, 721 GCCause::Cause gc_cause); 722 723 void wait_for_root_region_scanning(); 724 725 // The guts of the incremental collection pause, executed by the vm 726 // thread. It returns false if it is unable to do the collection due 727 // to the GC locker being active, true otherwise 728 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 729 730 // Actually do the work of evacuating the collection set. 731 void evacuate_collection_set(G1ParScanThreadStateSet* per_thread_states); 732 733 void pre_evacuate_collection_set(); 734 void post_evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* pss); 735 736 // Print the header for the per-thread termination statistics. 737 static void print_termination_stats_hdr(); 738 // Print actual per-thread termination statistics. 739 void print_termination_stats(uint worker_id, 740 double elapsed_ms, 741 double strong_roots_ms, 742 double term_ms, 743 size_t term_attempts, 744 size_t alloc_buffer_waste, 745 size_t undo_waste) const; 746 // Update object copying statistics. 747 void record_obj_copy_mem_stats(); 748 749 // The hot card cache for remembered set insertion optimization. 750 G1HotCardCache* _hot_card_cache; 751 752 // The g1 remembered set of the heap. 753 G1RemSet* _g1_rem_set; 754 755 // A set of cards that cover the objects for which the Rsets should be updated 756 // concurrently after the collection. 757 DirtyCardQueueSet _dirty_card_queue_set; 758 759 // After a collection pause, convert the regions in the collection set into free 760 // regions. 761 void free_collection_set(G1CollectionSet* collection_set, EvacuationInfo& evacuation_info, const size_t* surviving_young_words); 762 763 // Abandon the current collection set without recording policy 764 // statistics or updating free lists. 765 void abandon_collection_set(G1CollectionSet* collection_set); 766 767 // The concurrent marker (and the thread it runs in.) 768 G1ConcurrentMark* _cm; 769 G1ConcurrentMarkThread* _cm_thread; 770 771 // The concurrent refiner. 772 G1ConcurrentRefine* _cr; 773 774 // The parallel task queues 775 RefToScanQueueSet *_task_queues; 776 777 // True iff a evacuation has failed in the current collection. 778 bool _evacuation_failed; 779 780 EvacuationFailedInfo* _evacuation_failed_info_array; 781 782 // Failed evacuations cause some logical from-space objects to have 783 // forwarding pointers to themselves. Reset them. 784 void remove_self_forwarding_pointers(); 785 786 // Restore the objects in the regions in the collection set after an 787 // evacuation failure. 788 void restore_after_evac_failure(); 789 790 PreservedMarksSet _preserved_marks_set; 791 792 // Preserve the mark of "obj", if necessary, in preparation for its mark 793 // word being overwritten with a self-forwarding-pointer. 794 void preserve_mark_during_evac_failure(uint worker_id, oop obj, markOop m); 795 796 #ifndef PRODUCT 797 // Support for forcing evacuation failures. Analogous to 798 // PromotionFailureALot for the other collectors. 799 800 // Records whether G1EvacuationFailureALot should be in effect 801 // for the current GC 802 bool _evacuation_failure_alot_for_current_gc; 803 804 // Used to record the GC number for interval checking when 805 // determining whether G1EvaucationFailureALot is in effect 806 // for the current GC. 807 size_t _evacuation_failure_alot_gc_number; 808 809 // Count of the number of evacuations between failures. 810 volatile size_t _evacuation_failure_alot_count; 811 812 // Set whether G1EvacuationFailureALot should be in effect 813 // for the current GC (based upon the type of GC and which 814 // command line flags are set); 815 inline bool evacuation_failure_alot_for_gc_type(bool for_young_gc, 816 bool during_initial_mark, 817 bool mark_or_rebuild_in_progress); 818 819 inline void set_evacuation_failure_alot_for_current_gc(); 820 821 // Return true if it's time to cause an evacuation failure. 822 inline bool evacuation_should_fail(); 823 824 // Reset the G1EvacuationFailureALot counters. Should be called at 825 // the end of an evacuation pause in which an evacuation failure occurred. 826 inline void reset_evacuation_should_fail(); 827 #endif // !PRODUCT 828 829 // ("Weak") Reference processing support. 830 // 831 // G1 has 2 instances of the reference processor class. One 832 // (_ref_processor_cm) handles reference object discovery 833 // and subsequent processing during concurrent marking cycles. 834 // 835 // The other (_ref_processor_stw) handles reference object 836 // discovery and processing during full GCs and incremental 837 // evacuation pauses. 838 // 839 // During an incremental pause, reference discovery will be 840 // temporarily disabled for _ref_processor_cm and will be 841 // enabled for _ref_processor_stw. At the end of the evacuation 842 // pause references discovered by _ref_processor_stw will be 843 // processed and discovery will be disabled. The previous 844 // setting for reference object discovery for _ref_processor_cm 845 // will be re-instated. 846 // 847 // At the start of marking: 848 // * Discovery by the CM ref processor is verified to be inactive 849 // and it's discovered lists are empty. 850 // * Discovery by the CM ref processor is then enabled. 851 // 852 // At the end of marking: 853 // * Any references on the CM ref processor's discovered 854 // lists are processed (possibly MT). 855 // 856 // At the start of full GC we: 857 // * Disable discovery by the CM ref processor and 858 // empty CM ref processor's discovered lists 859 // (without processing any entries). 860 // * Verify that the STW ref processor is inactive and it's 861 // discovered lists are empty. 862 // * Temporarily set STW ref processor discovery as single threaded. 863 // * Temporarily clear the STW ref processor's _is_alive_non_header 864 // field. 865 // * Finally enable discovery by the STW ref processor. 866 // 867 // The STW ref processor is used to record any discovered 868 // references during the full GC. 869 // 870 // At the end of a full GC we: 871 // * Enqueue any reference objects discovered by the STW ref processor 872 // that have non-live referents. This has the side-effect of 873 // making the STW ref processor inactive by disabling discovery. 874 // * Verify that the CM ref processor is still inactive 875 // and no references have been placed on it's discovered 876 // lists (also checked as a precondition during initial marking). 877 878 // The (stw) reference processor... 879 ReferenceProcessor* _ref_processor_stw; 880 881 // During reference object discovery, the _is_alive_non_header 882 // closure (if non-null) is applied to the referent object to 883 // determine whether the referent is live. If so then the 884 // reference object does not need to be 'discovered' and can 885 // be treated as a regular oop. This has the benefit of reducing 886 // the number of 'discovered' reference objects that need to 887 // be processed. 888 // 889 // Instance of the is_alive closure for embedding into the 890 // STW reference processor as the _is_alive_non_header field. 891 // Supplying a value for the _is_alive_non_header field is 892 // optional but doing so prevents unnecessary additions to 893 // the discovered lists during reference discovery. 894 G1STWIsAliveClosure _is_alive_closure_stw; 895 896 // The (concurrent marking) reference processor... 897 ReferenceProcessor* _ref_processor_cm; 898 899 // Instance of the concurrent mark is_alive closure for embedding 900 // into the Concurrent Marking reference processor as the 901 // _is_alive_non_header field. Supplying a value for the 902 // _is_alive_non_header field is optional but doing so prevents 903 // unnecessary additions to the discovered lists during reference 904 // discovery. 905 G1CMIsAliveClosure _is_alive_closure_cm; 906 907 public: 908 909 RefToScanQueue *task_queue(uint i) const; 910 911 uint num_task_queues() const; 912 913 // A set of cards where updates happened during the GC 914 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; } 915 916 // Create a G1CollectedHeap with the specified policy. 917 // Must call the initialize method afterwards. 918 // May not return if something goes wrong. 919 G1CollectedHeap(G1CollectorPolicy* policy); 920 921 private: 922 jint initialize_concurrent_refinement(); 923 jint initialize_young_gen_sampling_thread(); 924 public: 925 // Initialize the G1CollectedHeap to have the initial and 926 // maximum sizes and remembered and barrier sets 927 // specified by the policy object. 928 jint initialize(); 929 930 virtual void stop(); 931 virtual void safepoint_synchronize_begin(); 932 virtual void safepoint_synchronize_end(); 933 934 // Return the (conservative) maximum heap alignment for any G1 heap 935 static size_t conservative_max_heap_alignment(); 936 937 // Does operations required after initialization has been done. 938 void post_initialize(); 939 940 // Initialize weak reference processing. 941 void ref_processing_init(); 942 943 virtual Name kind() const { 944 return CollectedHeap::G1; 945 } 946 947 virtual const char* name() const { 948 return "G1"; 949 } 950 951 const G1CollectorState* collector_state() const { return &_collector_state; } 952 G1CollectorState* collector_state() { return &_collector_state; } 953 954 // The current policy object for the collector. 955 G1Policy* g1_policy() const { return _g1_policy; } 956 957 const G1CollectionSet* collection_set() const { return &_collection_set; } 958 G1CollectionSet* collection_set() { return &_collection_set; } 959 960 virtual CollectorPolicy* collector_policy() const; 961 962 virtual SoftRefPolicy* soft_ref_policy(); 963 964 virtual GrowableArray<GCMemoryManager*> memory_managers(); 965 virtual GrowableArray<MemoryPool*> memory_pools(); 966 967 // The rem set and barrier set. 968 G1RemSet* g1_rem_set() const { return _g1_rem_set; } 969 970 // Try to minimize the remembered set. 971 void scrub_rem_set(); 972 973 // Apply the given closure on all cards in the Hot Card Cache, emptying it. 974 void iterate_hcc_closure(CardTableEntryClosure* cl, uint worker_i); 975 976 // Apply the given closure on all cards in the Dirty Card Queue Set, emptying it. 977 void iterate_dirty_card_closure(CardTableEntryClosure* cl, uint worker_i); 978 979 // The shared block offset table array. 980 G1BlockOffsetTable* bot() const { return _bot; } 981 982 // Reference Processing accessors 983 984 // The STW reference processor.... 985 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 986 987 G1NewTracer* gc_tracer_stw() const { return _gc_tracer_stw; } 988 989 // The Concurrent Marking reference processor... 990 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 991 992 size_t unused_committed_regions_in_bytes() const; 993 virtual size_t capacity() const; 994 virtual size_t used() const; 995 // This should be called when we're not holding the heap lock. The 996 // result might be a bit inaccurate. 997 size_t used_unlocked() const; 998 size_t recalculate_used() const; 999 1000 // These virtual functions do the actual allocation. 1001 // Some heaps may offer a contiguous region for shared non-blocking 1002 // allocation, via inlined code (by exporting the address of the top and 1003 // end fields defining the extent of the contiguous allocation region.) 1004 // But G1CollectedHeap doesn't yet support this. 1005 1006 virtual bool is_maximal_no_gc() const { 1007 return _hrm.available() == 0; 1008 } 1009 1010 // Returns whether there are any regions left in the heap for allocation. 1011 bool has_regions_left_for_allocation() const { 1012 return !is_maximal_no_gc() || num_free_regions() != 0; 1013 } 1014 1015 // The current number of regions in the heap. 1016 uint num_regions() const { return _hrm.length(); } 1017 1018 // The max number of regions in the heap. 1019 uint max_regions() const { return _hrm.max_length(); } 1020 1021 // The number of regions that are completely free. 1022 uint num_free_regions() const { return _hrm.num_free_regions(); } 1023 1024 MemoryUsage get_auxiliary_data_memory_usage() const { 1025 return _hrm.get_auxiliary_data_memory_usage(); 1026 } 1027 1028 // The number of regions that are not completely free. 1029 uint num_used_regions() const { return num_regions() - num_free_regions(); } 1030 1031 #ifdef ASSERT 1032 bool is_on_master_free_list(HeapRegion* hr) { 1033 return _hrm.is_free(hr); 1034 } 1035 #endif // ASSERT 1036 1037 inline void old_set_add(HeapRegion* hr); 1038 inline void old_set_remove(HeapRegion* hr); 1039 1040 size_t non_young_capacity_bytes() { 1041 return (_old_set.length() + _humongous_set.length()) * HeapRegion::GrainBytes; 1042 } 1043 1044 // Determine whether the given region is one that we are using as an 1045 // old GC alloc region. 1046 bool is_old_gc_alloc_region(HeapRegion* hr); 1047 1048 // Perform a collection of the heap; intended for use in implementing 1049 // "System.gc". This probably implies as full a collection as the 1050 // "CollectedHeap" supports. 1051 virtual void collect(GCCause::Cause cause); 1052 1053 // True iff an evacuation has failed in the most-recent collection. 1054 bool evacuation_failed() { return _evacuation_failed; } 1055 1056 void remove_from_old_sets(const uint old_regions_removed, const uint humongous_regions_removed); 1057 void prepend_to_freelist(FreeRegionList* list); 1058 void decrement_summary_bytes(size_t bytes); 1059 1060 virtual bool is_in(const void* p) const; 1061 #ifdef ASSERT 1062 // Returns whether p is in one of the available areas of the heap. Slow but 1063 // extensive version. 1064 bool is_in_exact(const void* p) const; 1065 #endif 1066 1067 // Return "TRUE" iff the given object address is within the collection 1068 // set. Assumes that the reference points into the heap. 1069 inline bool is_in_cset(const HeapRegion *hr); 1070 inline bool is_in_cset(oop obj); 1071 inline bool is_in_cset(HeapWord* addr); 1072 1073 inline bool is_in_cset_or_humongous(const oop obj); 1074 1075 private: 1076 // This array is used for a quick test on whether a reference points into 1077 // the collection set or not. Each of the array's elements denotes whether the 1078 // corresponding region is in the collection set or not. 1079 G1InCSetStateFastTestBiasedMappedArray _in_cset_fast_test; 1080 1081 public: 1082 1083 inline InCSetState in_cset_state(const oop obj); 1084 1085 // Return "TRUE" iff the given object address is in the reserved 1086 // region of g1. 1087 bool is_in_g1_reserved(const void* p) const { 1088 return _hrm.reserved().contains(p); 1089 } 1090 1091 // Returns a MemRegion that corresponds to the space that has been 1092 // reserved for the heap 1093 MemRegion g1_reserved() const { 1094 return _hrm.reserved(); 1095 } 1096 1097 virtual bool is_in_closed_subset(const void* p) const; 1098 1099 G1HotCardCache* g1_hot_card_cache() const { return _hot_card_cache; } 1100 1101 G1CardTable* card_table() const { 1102 return _card_table; 1103 } 1104 1105 // Iteration functions. 1106 1107 // Iterate over all objects, calling "cl.do_object" on each. 1108 virtual void object_iterate(ObjectClosure* cl); 1109 1110 virtual void safe_object_iterate(ObjectClosure* cl) { 1111 object_iterate(cl); 1112 } 1113 1114 // Iterate over heap regions, in address order, terminating the 1115 // iteration early if the "do_heap_region" method returns "true". 1116 void heap_region_iterate(HeapRegionClosure* blk) const; 1117 1118 // Return the region with the given index. It assumes the index is valid. 1119 inline HeapRegion* region_at(uint index) const; 1120 1121 // Return the next region (by index) that is part of the same 1122 // humongous object that hr is part of. 1123 inline HeapRegion* next_region_in_humongous(HeapRegion* hr) const; 1124 1125 // Calculate the region index of the given address. Given address must be 1126 // within the heap. 1127 inline uint addr_to_region(HeapWord* addr) const; 1128 1129 inline HeapWord* bottom_addr_for_region(uint index) const; 1130 1131 // Two functions to iterate over the heap regions in parallel. Threads 1132 // compete using the HeapRegionClaimer to claim the regions before 1133 // applying the closure on them. 1134 // The _from_worker_offset version uses the HeapRegionClaimer and 1135 // the worker id to calculate a start offset to prevent all workers to 1136 // start from the point. 1137 void heap_region_par_iterate_from_worker_offset(HeapRegionClosure* cl, 1138 HeapRegionClaimer* hrclaimer, 1139 uint worker_id) const; 1140 1141 void heap_region_par_iterate_from_start(HeapRegionClosure* cl, 1142 HeapRegionClaimer* hrclaimer) const; 1143 1144 // Iterate over the regions (if any) in the current collection set. 1145 void collection_set_iterate(HeapRegionClosure* blk); 1146 1147 // Iterate over the regions (if any) in the current collection set. Starts the 1148 // iteration over the entire collection set so that the start regions of a given 1149 // worker id over the set active_workers are evenly spread across the set of 1150 // collection set regions. 1151 void collection_set_iterate_from(HeapRegionClosure *blk, uint worker_id); 1152 1153 // Returns the HeapRegion that contains addr. addr must not be NULL. 1154 template <class T> 1155 inline HeapRegion* heap_region_containing(const T addr) const; 1156 1157 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1158 // each address in the (reserved) heap is a member of exactly 1159 // one block. The defining characteristic of a block is that it is 1160 // possible to find its size, and thus to progress forward to the next 1161 // block. (Blocks may be of different sizes.) Thus, blocks may 1162 // represent Java objects, or they might be free blocks in a 1163 // free-list-based heap (or subheap), as long as the two kinds are 1164 // distinguishable and the size of each is determinable. 1165 1166 // Returns the address of the start of the "block" that contains the 1167 // address "addr". We say "blocks" instead of "object" since some heaps 1168 // may not pack objects densely; a chunk may either be an object or a 1169 // non-object. 1170 virtual HeapWord* block_start(const void* addr) const; 1171 1172 // Requires "addr" to be the start of a chunk, and returns its size. 1173 // "addr + size" is required to be the start of a new chunk, or the end 1174 // of the active area of the heap. 1175 virtual size_t block_size(const HeapWord* addr) const; 1176 1177 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1178 // the block is an object. 1179 virtual bool block_is_obj(const HeapWord* addr) const; 1180 1181 // Section on thread-local allocation buffers (TLABs) 1182 // See CollectedHeap for semantics. 1183 1184 bool supports_tlab_allocation() const; 1185 size_t tlab_capacity(Thread* ignored) const; 1186 size_t tlab_used(Thread* ignored) const; 1187 size_t max_tlab_size() const; 1188 size_t unsafe_max_tlab_alloc(Thread* ignored) const; 1189 1190 inline bool is_in_young(const oop obj); 1191 1192 // Returns "true" iff the given word_size is "very large". 1193 static bool is_humongous(size_t word_size) { 1194 // Note this has to be strictly greater-than as the TLABs 1195 // are capped at the humongous threshold and we want to 1196 // ensure that we don't try to allocate a TLAB as 1197 // humongous and that we don't allocate a humongous 1198 // object in a TLAB. 1199 return word_size > _humongous_object_threshold_in_words; 1200 } 1201 1202 // Returns the humongous threshold for a specific region size 1203 static size_t humongous_threshold_for(size_t region_size) { 1204 return (region_size / 2); 1205 } 1206 1207 // Returns the number of regions the humongous object of the given word size 1208 // requires. 1209 static size_t humongous_obj_size_in_regions(size_t word_size); 1210 1211 // Print the maximum heap capacity. 1212 virtual size_t max_capacity() const; 1213 1214 virtual jlong millis_since_last_gc(); 1215 1216 1217 // Convenience function to be used in situations where the heap type can be 1218 // asserted to be this type. 1219 static G1CollectedHeap* heap(); 1220 1221 void set_region_short_lived_locked(HeapRegion* hr); 1222 // add appropriate methods for any other surv rate groups 1223 1224 const G1SurvivorRegions* survivor() const { return &_survivor; } 1225 1226 uint survivor_regions_count() const { 1227 return _survivor.length(); 1228 } 1229 1230 uint eden_regions_count() const { 1231 return _eden.length(); 1232 } 1233 1234 uint young_regions_count() const { 1235 return _eden.length() + _survivor.length(); 1236 } 1237 1238 uint old_regions_count() const { return _old_set.length(); } 1239 1240 uint humongous_regions_count() const { return _humongous_set.length(); } 1241 1242 #ifdef ASSERT 1243 bool check_young_list_empty(); 1244 #endif 1245 1246 // *** Stuff related to concurrent marking. It's not clear to me that so 1247 // many of these need to be public. 1248 1249 // The functions below are helper functions that a subclass of 1250 // "CollectedHeap" can use in the implementation of its virtual 1251 // functions. 1252 // This performs a concurrent marking of the live objects in a 1253 // bitmap off to the side. 1254 void do_concurrent_mark(); 1255 1256 bool is_marked_next(oop obj) const; 1257 1258 // Determine if an object is dead, given the object and also 1259 // the region to which the object belongs. An object is dead 1260 // iff a) it was not allocated since the last mark, b) it 1261 // is not marked, and c) it is not in an archive region. 1262 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1263 return 1264 hr->is_obj_dead(obj, _cm->prev_mark_bitmap()) && 1265 !hr->is_archive(); 1266 } 1267 1268 // This function returns true when an object has been 1269 // around since the previous marking and hasn't yet 1270 // been marked during this marking, and is not in an archive region. 1271 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1272 return 1273 !hr->obj_allocated_since_next_marking(obj) && 1274 !is_marked_next(obj) && 1275 !hr->is_archive(); 1276 } 1277 1278 // Determine if an object is dead, given only the object itself. 1279 // This will find the region to which the object belongs and 1280 // then call the region version of the same function. 1281 1282 // Added if it is NULL it isn't dead. 1283 1284 inline bool is_obj_dead(const oop obj) const; 1285 1286 inline bool is_obj_ill(const oop obj) const; 1287 1288 inline bool is_obj_dead_full(const oop obj, const HeapRegion* hr) const; 1289 inline bool is_obj_dead_full(const oop obj) const; 1290 1291 inline bool requires_marking(const void* entry) const; 1292 1293 G1ConcurrentMark* concurrent_mark() const { return _cm; } 1294 1295 // Refinement 1296 1297 G1ConcurrentRefine* concurrent_refine() const { return _cr; } 1298 1299 // Optimized nmethod scanning support routines 1300 1301 // Is an oop scavengeable 1302 virtual bool is_scavengable(oop obj); 1303 1304 // Register the given nmethod with the G1 heap. 1305 virtual void register_nmethod(nmethod* nm); 1306 1307 // Unregister the given nmethod from the G1 heap. 1308 virtual void unregister_nmethod(nmethod* nm); 1309 1310 // Free up superfluous code root memory. 1311 void purge_code_root_memory(); 1312 1313 // Rebuild the strong code root lists for each region 1314 // after a full GC. 1315 void rebuild_strong_code_roots(); 1316 1317 // Partial cleaning used when class unloading is disabled. 1318 // Let the caller choose what structures to clean out: 1319 // - StringTable 1320 // - SymbolTable 1321 // - StringDeduplication structures 1322 void partial_cleaning(BoolObjectClosure* is_alive, bool unlink_strings, bool unlink_symbols, bool unlink_string_dedup); 1323 1324 // Complete cleaning used when class unloading is enabled. 1325 // Cleans out all structures handled by partial_cleaning and also the CodeCache. 1326 void complete_cleaning(BoolObjectClosure* is_alive, bool class_unloading_occurred); 1327 1328 // Redirty logged cards in the refinement queue. 1329 void redirty_logged_cards(); 1330 // Verification 1331 1332 // Perform any cleanup actions necessary before allowing a verification. 1333 virtual void prepare_for_verify(); 1334 1335 // Perform verification. 1336 1337 // vo == UsePrevMarking -> use "prev" marking information, 1338 // vo == UseNextMarking -> use "next" marking information 1339 // vo == UseFullMarking -> use "next" marking bitmap but no TAMS 1340 // 1341 // NOTE: Only the "prev" marking information is guaranteed to be 1342 // consistent most of the time, so most calls to this should use 1343 // vo == UsePrevMarking. 1344 // Currently, there is only one case where this is called with 1345 // vo == UseNextMarking, which is to verify the "next" marking 1346 // information at the end of remark. 1347 // Currently there is only one place where this is called with 1348 // vo == UseFullMarking, which is to verify the marking during a 1349 // full GC. 1350 void verify(VerifyOption vo); 1351 1352 // WhiteBox testing support. 1353 virtual bool supports_concurrent_phase_control() const; 1354 virtual const char* const* concurrent_phases() const; 1355 virtual bool request_concurrent_phase(const char* phase); 1356 1357 // The methods below are here for convenience and dispatch the 1358 // appropriate method depending on value of the given VerifyOption 1359 // parameter. The values for that parameter, and their meanings, 1360 // are the same as those above. 1361 1362 bool is_obj_dead_cond(const oop obj, 1363 const HeapRegion* hr, 1364 const VerifyOption vo) const; 1365 1366 bool is_obj_dead_cond(const oop obj, 1367 const VerifyOption vo) const; 1368 1369 G1HeapSummary create_g1_heap_summary(); 1370 G1EvacSummary create_g1_evac_summary(G1EvacStats* stats); 1371 1372 // Printing 1373 private: 1374 void print_heap_regions() const; 1375 void print_regions_on(outputStream* st) const; 1376 1377 public: 1378 virtual void print_on(outputStream* st) const; 1379 virtual void print_extended_on(outputStream* st) const; 1380 virtual void print_on_error(outputStream* st) const; 1381 1382 virtual void print_gc_threads_on(outputStream* st) const; 1383 virtual void gc_threads_do(ThreadClosure* tc) const; 1384 1385 // Override 1386 void print_tracing_info() const; 1387 1388 // The following two methods are helpful for debugging RSet issues. 1389 void print_cset_rsets() PRODUCT_RETURN; 1390 void print_all_rsets() PRODUCT_RETURN; 1391 1392 public: 1393 size_t pending_card_num(); 1394 1395 private: 1396 size_t _max_heap_capacity; 1397 }; 1398 1399 class G1ParEvacuateFollowersClosure : public VoidClosure { 1400 private: 1401 double _start_term; 1402 double _term_time; 1403 size_t _term_attempts; 1404 1405 void start_term_time() { _term_attempts++; _start_term = os::elapsedTime(); } 1406 void end_term_time() { _term_time += os::elapsedTime() - _start_term; } 1407 protected: 1408 G1CollectedHeap* _g1h; 1409 G1ParScanThreadState* _par_scan_state; 1410 RefToScanQueueSet* _queues; 1411 ParallelTaskTerminator* _terminator; 1412 1413 G1ParScanThreadState* par_scan_state() { return _par_scan_state; } 1414 RefToScanQueueSet* queues() { return _queues; } 1415 ParallelTaskTerminator* terminator() { return _terminator; } 1416 1417 public: 1418 G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h, 1419 G1ParScanThreadState* par_scan_state, 1420 RefToScanQueueSet* queues, 1421 ParallelTaskTerminator* terminator) 1422 : _g1h(g1h), _par_scan_state(par_scan_state), 1423 _queues(queues), _terminator(terminator), 1424 _start_term(0.0), _term_time(0.0), _term_attempts(0) {} 1425 1426 void do_void(); 1427 1428 double term_time() const { return _term_time; } 1429 size_t term_attempts() const { return _term_attempts; } 1430 1431 private: 1432 inline bool offer_termination(); 1433 }; 1434 1435 #endif // SHARE_VM_GC_G1_G1COLLECTEDHEAP_HPP