1 /* 2 * Copyright (c) 2001, 2012, 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_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP 27 28 #include "gc_implementation/g1/concurrentMark.hpp" 29 #include "gc_implementation/g1/g1AllocRegion.hpp" 30 #include "gc_implementation/g1/g1HRPrinter.hpp" 31 #include "gc_implementation/g1/g1RemSet.hpp" 32 #include "gc_implementation/g1/g1MonitoringSupport.hpp" 33 #include "gc_implementation/g1/heapRegionSeq.hpp" 34 #include "gc_implementation/g1/heapRegionSets.hpp" 35 #include "gc_implementation/shared/hSpaceCounters.hpp" 36 #include "gc_implementation/parNew/parGCAllocBuffer.hpp" 37 #include "memory/barrierSet.hpp" 38 #include "memory/memRegion.hpp" 39 #include "memory/sharedHeap.hpp" 40 41 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot. 42 // It uses the "Garbage First" heap organization and algorithm, which 43 // may combine concurrent marking with parallel, incremental compaction of 44 // heap subsets that will yield large amounts of garbage. 45 46 class HeapRegion; 47 class HRRSCleanupTask; 48 class PermanentGenerationSpec; 49 class GenerationSpec; 50 class OopsInHeapRegionClosure; 51 class G1ScanHeapEvacClosure; 52 class ObjectClosure; 53 class SpaceClosure; 54 class CompactibleSpaceClosure; 55 class Space; 56 class G1CollectorPolicy; 57 class GenRemSet; 58 class G1RemSet; 59 class HeapRegionRemSetIterator; 60 class ConcurrentMark; 61 class ConcurrentMarkThread; 62 class ConcurrentG1Refine; 63 class GenerationCounters; 64 65 typedef OverflowTaskQueue<StarTask> RefToScanQueue; 66 typedef GenericTaskQueueSet<RefToScanQueue> RefToScanQueueSet; 67 68 typedef int RegionIdx_t; // needs to hold [ 0..max_regions() ) 69 typedef int CardIdx_t; // needs to hold [ 0..CardsPerRegion ) 70 71 enum GCAllocPurpose { 72 GCAllocForTenured, 73 GCAllocForSurvived, 74 GCAllocPurposeCount 75 }; 76 77 class YoungList : public CHeapObj { 78 private: 79 G1CollectedHeap* _g1h; 80 81 HeapRegion* _head; 82 83 HeapRegion* _survivor_head; 84 HeapRegion* _survivor_tail; 85 86 HeapRegion* _curr; 87 88 uint _length; 89 uint _survivor_length; 90 91 size_t _last_sampled_rs_lengths; 92 size_t _sampled_rs_lengths; 93 94 void empty_list(HeapRegion* list); 95 96 public: 97 YoungList(G1CollectedHeap* g1h); 98 99 void push_region(HeapRegion* hr); 100 void add_survivor_region(HeapRegion* hr); 101 102 void empty_list(); 103 bool is_empty() { return _length == 0; } 104 uint length() { return _length; } 105 uint survivor_length() { return _survivor_length; } 106 107 // Currently we do not keep track of the used byte sum for the 108 // young list and the survivors and it'd be quite a lot of work to 109 // do so. When we'll eventually replace the young list with 110 // instances of HeapRegionLinkedList we'll get that for free. So, 111 // we'll report the more accurate information then. 112 size_t eden_used_bytes() { 113 assert(length() >= survivor_length(), "invariant"); 114 return (size_t) (length() - survivor_length()) * HeapRegion::GrainBytes; 115 } 116 size_t survivor_used_bytes() { 117 return (size_t) survivor_length() * HeapRegion::GrainBytes; 118 } 119 120 void rs_length_sampling_init(); 121 bool rs_length_sampling_more(); 122 void rs_length_sampling_next(); 123 124 void reset_sampled_info() { 125 _last_sampled_rs_lengths = 0; 126 } 127 size_t sampled_rs_lengths() { return _last_sampled_rs_lengths; } 128 129 // for development purposes 130 void reset_auxilary_lists(); 131 void clear() { _head = NULL; _length = 0; } 132 133 void clear_survivors() { 134 _survivor_head = NULL; 135 _survivor_tail = NULL; 136 _survivor_length = 0; 137 } 138 139 HeapRegion* first_region() { return _head; } 140 HeapRegion* first_survivor_region() { return _survivor_head; } 141 HeapRegion* last_survivor_region() { return _survivor_tail; } 142 143 // debugging 144 bool check_list_well_formed(); 145 bool check_list_empty(bool check_sample = true); 146 void print(); 147 }; 148 149 class MutatorAllocRegion : public G1AllocRegion { 150 protected: 151 virtual HeapRegion* allocate_new_region(size_t word_size, bool force); 152 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes); 153 public: 154 MutatorAllocRegion() 155 : G1AllocRegion("Mutator Alloc Region", false /* bot_updates */) { } 156 }; 157 158 // The G1 STW is alive closure. 159 // An instance is embedded into the G1CH and used as the 160 // (optional) _is_alive_non_header closure in the STW 161 // reference processor. It is also extensively used during 162 // refence processing during STW evacuation pauses. 163 class G1STWIsAliveClosure: public BoolObjectClosure { 164 G1CollectedHeap* _g1; 165 public: 166 G1STWIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) {} 167 void do_object(oop p) { assert(false, "Do not call."); } 168 bool do_object_b(oop p); 169 }; 170 171 class SurvivorGCAllocRegion : public G1AllocRegion { 172 protected: 173 virtual HeapRegion* allocate_new_region(size_t word_size, bool force); 174 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes); 175 public: 176 SurvivorGCAllocRegion() 177 : G1AllocRegion("Survivor GC Alloc Region", false /* bot_updates */) { } 178 }; 179 180 class OldGCAllocRegion : public G1AllocRegion { 181 protected: 182 virtual HeapRegion* allocate_new_region(size_t word_size, bool force); 183 virtual void retire_region(HeapRegion* alloc_region, size_t allocated_bytes); 184 public: 185 OldGCAllocRegion() 186 : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { } 187 }; 188 189 class RefineCardTableEntryClosure; 190 191 class G1CollectedHeap : public SharedHeap { 192 friend class VM_G1CollectForAllocation; 193 friend class VM_GenCollectForPermanentAllocation; 194 friend class VM_G1CollectFull; 195 friend class VM_G1IncCollectionPause; 196 friend class VMStructs; 197 friend class MutatorAllocRegion; 198 friend class SurvivorGCAllocRegion; 199 friend class OldGCAllocRegion; 200 201 // Closures used in implementation. 202 template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_object> 203 friend class G1ParCopyClosure; 204 friend class G1IsAliveClosure; 205 friend class G1EvacuateFollowersClosure; 206 friend class G1ParScanThreadState; 207 friend class G1ParScanClosureSuper; 208 friend class G1ParEvacuateFollowersClosure; 209 friend class G1ParTask; 210 friend class G1FreeGarbageRegionClosure; 211 friend class RefineCardTableEntryClosure; 212 friend class G1PrepareCompactClosure; 213 friend class RegionSorter; 214 friend class RegionResetter; 215 friend class CountRCClosure; 216 friend class EvacPopObjClosure; 217 friend class G1ParCleanupCTTask; 218 219 // Other related classes. 220 friend class G1MarkSweep; 221 222 private: 223 // The one and only G1CollectedHeap, so static functions can find it. 224 static G1CollectedHeap* _g1h; 225 226 static size_t _humongous_object_threshold_in_words; 227 228 // Storage for the G1 heap (excludes the permanent generation). 229 VirtualSpace _g1_storage; 230 MemRegion _g1_reserved; 231 232 // The part of _g1_storage that is currently committed. 233 MemRegion _g1_committed; 234 235 // The master free list. It will satisfy all new region allocations. 236 MasterFreeRegionList _free_list; 237 238 // The secondary free list which contains regions that have been 239 // freed up during the cleanup process. This will be appended to the 240 // master free list when appropriate. 241 SecondaryFreeRegionList _secondary_free_list; 242 243 // It keeps track of the old regions. 244 MasterOldRegionSet _old_set; 245 246 // It keeps track of the humongous regions. 247 MasterHumongousRegionSet _humongous_set; 248 249 // The number of regions we could create by expansion. 250 uint _expansion_regions; 251 252 // The block offset table for the G1 heap. 253 G1BlockOffsetSharedArray* _bot_shared; 254 255 // Tears down the region sets / lists so that they are empty and the 256 // regions on the heap do not belong to a region set / list. The 257 // only exception is the humongous set which we leave unaltered. If 258 // free_list_only is true, it will only tear down the master free 259 // list. It is called before a Full GC (free_list_only == false) or 260 // before heap shrinking (free_list_only == true). 261 void tear_down_region_sets(bool free_list_only); 262 263 // Rebuilds the region sets / lists so that they are repopulated to 264 // reflect the contents of the heap. The only exception is the 265 // humongous set which was not torn down in the first place. If 266 // free_list_only is true, it will only rebuild the master free 267 // list. It is called after a Full GC (free_list_only == false) or 268 // after heap shrinking (free_list_only == true). 269 void rebuild_region_sets(bool free_list_only); 270 271 // The sequence of all heap regions in the heap. 272 HeapRegionSeq _hrs; 273 274 // Alloc region used to satisfy mutator allocation requests. 275 MutatorAllocRegion _mutator_alloc_region; 276 277 // Alloc region used to satisfy allocation requests by the GC for 278 // survivor objects. 279 SurvivorGCAllocRegion _survivor_gc_alloc_region; 280 281 // Alloc region used to satisfy allocation requests by the GC for 282 // old objects. 283 OldGCAllocRegion _old_gc_alloc_region; 284 285 // The last old region we allocated to during the last GC. 286 // Typically, it is not full so we should re-use it during the next GC. 287 HeapRegion* _retained_old_gc_alloc_region; 288 289 // It specifies whether we should attempt to expand the heap after a 290 // region allocation failure. If heap expansion fails we set this to 291 // false so that we don't re-attempt the heap expansion (it's likely 292 // that subsequent expansion attempts will also fail if one fails). 293 // Currently, it is only consulted during GC and it's reset at the 294 // start of each GC. 295 bool _expand_heap_after_alloc_failure; 296 297 // It resets the mutator alloc region before new allocations can take place. 298 void init_mutator_alloc_region(); 299 300 // It releases the mutator alloc region. 301 void release_mutator_alloc_region(); 302 303 // It initializes the GC alloc regions at the start of a GC. 304 void init_gc_alloc_regions(); 305 306 // It releases the GC alloc regions at the end of a GC. 307 void release_gc_alloc_regions(); 308 309 // It does any cleanup that needs to be done on the GC alloc regions 310 // before a Full GC. 311 void abandon_gc_alloc_regions(); 312 313 // Helper for monitoring and management support. 314 G1MonitoringSupport* _g1mm; 315 316 // Determines PLAB size for a particular allocation purpose. 317 static size_t desired_plab_sz(GCAllocPurpose purpose); 318 319 // Outside of GC pauses, the number of bytes used in all regions other 320 // than the current allocation region. 321 size_t _summary_bytes_used; 322 323 // This is used for a quick test on whether a reference points into 324 // the collection set or not. Basically, we have an array, with one 325 // byte per region, and that byte denotes whether the corresponding 326 // region is in the collection set or not. The entry corresponding 327 // the bottom of the heap, i.e., region 0, is pointed to by 328 // _in_cset_fast_test_base. The _in_cset_fast_test field has been 329 // biased so that it actually points to address 0 of the address 330 // space, to make the test as fast as possible (we can simply shift 331 // the address to address into it, instead of having to subtract the 332 // bottom of the heap from the address before shifting it; basically 333 // it works in the same way the card table works). 334 bool* _in_cset_fast_test; 335 336 // The allocated array used for the fast test on whether a reference 337 // points into the collection set or not. This field is also used to 338 // free the array. 339 bool* _in_cset_fast_test_base; 340 341 // The length of the _in_cset_fast_test_base array. 342 uint _in_cset_fast_test_length; 343 344 volatile unsigned _gc_time_stamp; 345 346 size_t* _surviving_young_words; 347 348 G1HRPrinter _hr_printer; 349 350 void setup_surviving_young_words(); 351 void update_surviving_young_words(size_t* surv_young_words); 352 void cleanup_surviving_young_words(); 353 354 // It decides whether an explicit GC should start a concurrent cycle 355 // instead of doing a STW GC. Currently, a concurrent cycle is 356 // explicitly started if: 357 // (a) cause == _gc_locker and +GCLockerInvokesConcurrent, or 358 // (b) cause == _java_lang_system_gc and +ExplicitGCInvokesConcurrent. 359 // (c) cause == _g1_humongous_allocation 360 bool should_do_concurrent_full_gc(GCCause::Cause cause); 361 362 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 363 // concurrent cycles) we have started. 364 volatile unsigned int _old_marking_cycles_started; 365 366 // Keeps track of how many "old marking cycles" (i.e., Full GCs or 367 // concurrent cycles) we have completed. 368 volatile unsigned int _old_marking_cycles_completed; 369 370 // This is a non-product method that is helpful for testing. It is 371 // called at the end of a GC and artificially expands the heap by 372 // allocating a number of dead regions. This way we can induce very 373 // frequent marking cycles and stress the cleanup / concurrent 374 // cleanup code more (as all the regions that will be allocated by 375 // this method will be found dead by the marking cycle). 376 void allocate_dummy_regions() PRODUCT_RETURN; 377 378 // These are macros so that, if the assert fires, we get the correct 379 // line number, file, etc. 380 381 #define heap_locking_asserts_err_msg(_extra_message_) \ 382 err_msg("%s : Heap_lock locked: %s, at safepoint: %s, is VM thread: %s", \ 383 (_extra_message_), \ 384 BOOL_TO_STR(Heap_lock->owned_by_self()), \ 385 BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), \ 386 BOOL_TO_STR(Thread::current()->is_VM_thread())) 387 388 #define assert_heap_locked() \ 389 do { \ 390 assert(Heap_lock->owned_by_self(), \ 391 heap_locking_asserts_err_msg("should be holding the Heap_lock")); \ 392 } while (0) 393 394 #define assert_heap_locked_or_at_safepoint(_should_be_vm_thread_) \ 395 do { \ 396 assert(Heap_lock->owned_by_self() || \ 397 (SafepointSynchronize::is_at_safepoint() && \ 398 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread())), \ 399 heap_locking_asserts_err_msg("should be holding the Heap_lock or " \ 400 "should be at a safepoint")); \ 401 } while (0) 402 403 #define assert_heap_locked_and_not_at_safepoint() \ 404 do { \ 405 assert(Heap_lock->owned_by_self() && \ 406 !SafepointSynchronize::is_at_safepoint(), \ 407 heap_locking_asserts_err_msg("should be holding the Heap_lock and " \ 408 "should not be at a safepoint")); \ 409 } while (0) 410 411 #define assert_heap_not_locked() \ 412 do { \ 413 assert(!Heap_lock->owned_by_self(), \ 414 heap_locking_asserts_err_msg("should not be holding the Heap_lock")); \ 415 } while (0) 416 417 #define assert_heap_not_locked_and_not_at_safepoint() \ 418 do { \ 419 assert(!Heap_lock->owned_by_self() && \ 420 !SafepointSynchronize::is_at_safepoint(), \ 421 heap_locking_asserts_err_msg("should not be holding the Heap_lock and " \ 422 "should not be at a safepoint")); \ 423 } while (0) 424 425 #define assert_at_safepoint(_should_be_vm_thread_) \ 426 do { \ 427 assert(SafepointSynchronize::is_at_safepoint() && \ 428 ((_should_be_vm_thread_) == Thread::current()->is_VM_thread()), \ 429 heap_locking_asserts_err_msg("should be at a safepoint")); \ 430 } while (0) 431 432 #define assert_not_at_safepoint() \ 433 do { \ 434 assert(!SafepointSynchronize::is_at_safepoint(), \ 435 heap_locking_asserts_err_msg("should not be at a safepoint")); \ 436 } while (0) 437 438 protected: 439 440 // The young region list. 441 YoungList* _young_list; 442 443 // The current policy object for the collector. 444 G1CollectorPolicy* _g1_policy; 445 446 // This is the second level of trying to allocate a new region. If 447 // new_region() didn't find a region on the free_list, this call will 448 // check whether there's anything available on the 449 // secondary_free_list and/or wait for more regions to appear on 450 // that list, if _free_regions_coming is set. 451 HeapRegion* new_region_try_secondary_free_list(); 452 453 // Try to allocate a single non-humongous HeapRegion sufficient for 454 // an allocation of the given word_size. If do_expand is true, 455 // attempt to expand the heap if necessary to satisfy the allocation 456 // request. 457 HeapRegion* new_region(size_t word_size, bool do_expand); 458 459 // Attempt to satisfy a humongous allocation request of the given 460 // size by finding a contiguous set of free regions of num_regions 461 // length and remove them from the master free list. Return the 462 // index of the first region or G1_NULL_HRS_INDEX if the search 463 // was unsuccessful. 464 uint humongous_obj_allocate_find_first(uint num_regions, 465 size_t word_size); 466 467 // Initialize a contiguous set of free regions of length num_regions 468 // and starting at index first so that they appear as a single 469 // humongous region. 470 HeapWord* humongous_obj_allocate_initialize_regions(uint first, 471 uint num_regions, 472 size_t word_size); 473 474 // Attempt to allocate a humongous object of the given size. Return 475 // NULL if unsuccessful. 476 HeapWord* humongous_obj_allocate(size_t word_size); 477 478 // The following two methods, allocate_new_tlab() and 479 // mem_allocate(), are the two main entry points from the runtime 480 // into the G1's allocation routines. They have the following 481 // assumptions: 482 // 483 // * They should both be called outside safepoints. 484 // 485 // * They should both be called without holding the Heap_lock. 486 // 487 // * All allocation requests for new TLABs should go to 488 // allocate_new_tlab(). 489 // 490 // * All non-TLAB allocation requests should go to mem_allocate(). 491 // 492 // * If either call cannot satisfy the allocation request using the 493 // current allocating region, they will try to get a new one. If 494 // this fails, they will attempt to do an evacuation pause and 495 // retry the allocation. 496 // 497 // * If all allocation attempts fail, even after trying to schedule 498 // an evacuation pause, allocate_new_tlab() will return NULL, 499 // whereas mem_allocate() will attempt a heap expansion and/or 500 // schedule a Full GC. 501 // 502 // * We do not allow humongous-sized TLABs. So, allocate_new_tlab 503 // should never be called with word_size being humongous. All 504 // humongous allocation requests should go to mem_allocate() which 505 // will satisfy them with a special path. 506 507 virtual HeapWord* allocate_new_tlab(size_t word_size); 508 509 virtual HeapWord* mem_allocate(size_t word_size, 510 bool* gc_overhead_limit_was_exceeded); 511 512 // The following three methods take a gc_count_before_ret 513 // parameter which is used to return the GC count if the method 514 // returns NULL. Given that we are required to read the GC count 515 // while holding the Heap_lock, and these paths will take the 516 // Heap_lock at some point, it's easier to get them to read the GC 517 // count while holding the Heap_lock before they return NULL instead 518 // of the caller (namely: mem_allocate()) having to also take the 519 // Heap_lock just to read the GC count. 520 521 // First-level mutator allocation attempt: try to allocate out of 522 // the mutator alloc region without taking the Heap_lock. This 523 // should only be used for non-humongous allocations. 524 inline HeapWord* attempt_allocation(size_t word_size, 525 unsigned int* gc_count_before_ret); 526 527 // Second-level mutator allocation attempt: take the Heap_lock and 528 // retry the allocation attempt, potentially scheduling a GC 529 // pause. This should only be used for non-humongous allocations. 530 HeapWord* attempt_allocation_slow(size_t word_size, 531 unsigned int* gc_count_before_ret); 532 533 // Takes the Heap_lock and attempts a humongous allocation. It can 534 // potentially schedule a GC pause. 535 HeapWord* attempt_allocation_humongous(size_t word_size, 536 unsigned int* gc_count_before_ret); 537 538 // Allocation attempt that should be called during safepoints (e.g., 539 // at the end of a successful GC). expect_null_mutator_alloc_region 540 // specifies whether the mutator alloc region is expected to be NULL 541 // or not. 542 HeapWord* attempt_allocation_at_safepoint(size_t word_size, 543 bool expect_null_mutator_alloc_region); 544 545 // It dirties the cards that cover the block so that so that the post 546 // write barrier never queues anything when updating objects on this 547 // block. It is assumed (and in fact we assert) that the block 548 // belongs to a young region. 549 inline void dirty_young_block(HeapWord* start, size_t word_size); 550 551 // Allocate blocks during garbage collection. Will ensure an 552 // allocation region, either by picking one or expanding the 553 // heap, and then allocate a block of the given size. The block 554 // may not be a humongous - it must fit into a single heap region. 555 HeapWord* par_allocate_during_gc(GCAllocPurpose purpose, size_t word_size); 556 557 HeapWord* allocate_during_gc_slow(GCAllocPurpose purpose, 558 HeapRegion* alloc_region, 559 bool par, 560 size_t word_size); 561 562 // Ensure that no further allocations can happen in "r", bearing in mind 563 // that parallel threads might be attempting allocations. 564 void par_allocate_remaining_space(HeapRegion* r); 565 566 // Allocation attempt during GC for a survivor object / PLAB. 567 inline HeapWord* survivor_attempt_allocation(size_t word_size); 568 569 // Allocation attempt during GC for an old object / PLAB. 570 inline HeapWord* old_attempt_allocation(size_t word_size); 571 572 // These methods are the "callbacks" from the G1AllocRegion class. 573 574 // For mutator alloc regions. 575 HeapRegion* new_mutator_alloc_region(size_t word_size, bool force); 576 void retire_mutator_alloc_region(HeapRegion* alloc_region, 577 size_t allocated_bytes); 578 579 // For GC alloc regions. 580 HeapRegion* new_gc_alloc_region(size_t word_size, uint count, 581 GCAllocPurpose ap); 582 void retire_gc_alloc_region(HeapRegion* alloc_region, 583 size_t allocated_bytes, GCAllocPurpose ap); 584 585 // - if explicit_gc is true, the GC is for a System.gc() or a heap 586 // inspection request and should collect the entire heap 587 // - if clear_all_soft_refs is true, all soft references should be 588 // cleared during the GC 589 // - if explicit_gc is false, word_size describes the allocation that 590 // the GC should attempt (at least) to satisfy 591 // - it returns false if it is unable to do the collection due to the 592 // GC locker being active, true otherwise 593 bool do_collection(bool explicit_gc, 594 bool clear_all_soft_refs, 595 size_t word_size); 596 597 // Callback from VM_G1CollectFull operation. 598 // Perform a full collection. 599 void do_full_collection(bool clear_all_soft_refs); 600 601 // Resize the heap if necessary after a full collection. If this is 602 // after a collect-for allocation, "word_size" is the allocation size, 603 // and will be considered part of the used portion of the heap. 604 void resize_if_necessary_after_full_collection(size_t word_size); 605 606 // Callback from VM_G1CollectForAllocation operation. 607 // This function does everything necessary/possible to satisfy a 608 // failed allocation request (including collection, expansion, etc.) 609 HeapWord* satisfy_failed_allocation(size_t word_size, bool* succeeded); 610 611 // Attempting to expand the heap sufficiently 612 // to support an allocation of the given "word_size". If 613 // successful, perform the allocation and return the address of the 614 // allocated block, or else "NULL". 615 HeapWord* expand_and_allocate(size_t word_size); 616 617 // Process any reference objects discovered during 618 // an incremental evacuation pause. 619 void process_discovered_references(); 620 621 // Enqueue any remaining discovered references 622 // after processing. 623 void enqueue_discovered_references(); 624 625 public: 626 627 G1MonitoringSupport* g1mm() { 628 assert(_g1mm != NULL, "should have been initialized"); 629 return _g1mm; 630 } 631 632 // Expand the garbage-first heap by at least the given size (in bytes!). 633 // Returns true if the heap was expanded by the requested amount; 634 // false otherwise. 635 // (Rounds up to a HeapRegion boundary.) 636 bool expand(size_t expand_bytes); 637 638 // Do anything common to GC's. 639 virtual void gc_prologue(bool full); 640 virtual void gc_epilogue(bool full); 641 642 // We register a region with the fast "in collection set" test. We 643 // simply set to true the array slot corresponding to this region. 644 void register_region_with_in_cset_fast_test(HeapRegion* r) { 645 assert(_in_cset_fast_test_base != NULL, "sanity"); 646 assert(r->in_collection_set(), "invariant"); 647 uint index = r->hrs_index(); 648 assert(index < _in_cset_fast_test_length, "invariant"); 649 assert(!_in_cset_fast_test_base[index], "invariant"); 650 _in_cset_fast_test_base[index] = true; 651 } 652 653 // This is a fast test on whether a reference points into the 654 // collection set or not. It does not assume that the reference 655 // points into the heap; if it doesn't, it will return false. 656 bool in_cset_fast_test(oop obj) { 657 assert(_in_cset_fast_test != NULL, "sanity"); 658 if (_g1_committed.contains((HeapWord*) obj)) { 659 // no need to subtract the bottom of the heap from obj, 660 // _in_cset_fast_test is biased 661 uintx index = (uintx) obj >> HeapRegion::LogOfHRGrainBytes; 662 bool ret = _in_cset_fast_test[index]; 663 // let's make sure the result is consistent with what the slower 664 // test returns 665 assert( ret || !obj_in_cs(obj), "sanity"); 666 assert(!ret || obj_in_cs(obj), "sanity"); 667 return ret; 668 } else { 669 return false; 670 } 671 } 672 673 void clear_cset_fast_test() { 674 assert(_in_cset_fast_test_base != NULL, "sanity"); 675 memset(_in_cset_fast_test_base, false, 676 (size_t) _in_cset_fast_test_length * sizeof(bool)); 677 } 678 679 // This is called at the start of either a concurrent cycle or a Full 680 // GC to update the number of old marking cycles started. 681 void increment_old_marking_cycles_started(); 682 683 // This is called at the end of either a concurrent cycle or a Full 684 // GC to update the number of old marking cycles completed. Those two 685 // can happen in a nested fashion, i.e., we start a concurrent 686 // cycle, a Full GC happens half-way through it which ends first, 687 // and then the cycle notices that a Full GC happened and ends 688 // too. The concurrent parameter is a boolean to help us do a bit 689 // tighter consistency checking in the method. If concurrent is 690 // false, the caller is the inner caller in the nesting (i.e., the 691 // Full GC). If concurrent is true, the caller is the outer caller 692 // in this nesting (i.e., the concurrent cycle). Further nesting is 693 // not currently supported. The end of this call also notifies 694 // the FullGCCount_lock in case a Java thread is waiting for a full 695 // GC to happen (e.g., it called System.gc() with 696 // +ExplicitGCInvokesConcurrent). 697 void increment_old_marking_cycles_completed(bool concurrent); 698 699 unsigned int old_marking_cycles_completed() { 700 return _old_marking_cycles_completed; 701 } 702 703 G1HRPrinter* hr_printer() { return &_hr_printer; } 704 705 protected: 706 707 // Shrink the garbage-first heap by at most the given size (in bytes!). 708 // (Rounds down to a HeapRegion boundary.) 709 virtual void shrink(size_t expand_bytes); 710 void shrink_helper(size_t expand_bytes); 711 712 #if TASKQUEUE_STATS 713 static void print_taskqueue_stats_hdr(outputStream* const st = gclog_or_tty); 714 void print_taskqueue_stats(outputStream* const st = gclog_or_tty) const; 715 void reset_taskqueue_stats(); 716 #endif // TASKQUEUE_STATS 717 718 // Schedule the VM operation that will do an evacuation pause to 719 // satisfy an allocation request of word_size. *succeeded will 720 // return whether the VM operation was successful (it did do an 721 // evacuation pause) or not (another thread beat us to it or the GC 722 // locker was active). Given that we should not be holding the 723 // Heap_lock when we enter this method, we will pass the 724 // gc_count_before (i.e., total_collections()) as a parameter since 725 // it has to be read while holding the Heap_lock. Currently, both 726 // methods that call do_collection_pause() release the Heap_lock 727 // before the call, so it's easy to read gc_count_before just before. 728 HeapWord* do_collection_pause(size_t word_size, 729 unsigned int gc_count_before, 730 bool* succeeded); 731 732 // The guts of the incremental collection pause, executed by the vm 733 // thread. It returns false if it is unable to do the collection due 734 // to the GC locker being active, true otherwise 735 bool do_collection_pause_at_safepoint(double target_pause_time_ms); 736 737 // Actually do the work of evacuating the collection set. 738 void evacuate_collection_set(); 739 740 // The g1 remembered set of the heap. 741 G1RemSet* _g1_rem_set; 742 // And it's mod ref barrier set, used to track updates for the above. 743 ModRefBarrierSet* _mr_bs; 744 745 // A set of cards that cover the objects for which the Rsets should be updated 746 // concurrently after the collection. 747 DirtyCardQueueSet _dirty_card_queue_set; 748 749 // The Heap Region Rem Set Iterator. 750 HeapRegionRemSetIterator** _rem_set_iterator; 751 752 // The closure used to refine a single card. 753 RefineCardTableEntryClosure* _refine_cte_cl; 754 755 // A function to check the consistency of dirty card logs. 756 void check_ct_logs_at_safepoint(); 757 758 // A DirtyCardQueueSet that is used to hold cards that contain 759 // references into the current collection set. This is used to 760 // update the remembered sets of the regions in the collection 761 // set in the event of an evacuation failure. 762 DirtyCardQueueSet _into_cset_dirty_card_queue_set; 763 764 // After a collection pause, make the regions in the CS into free 765 // regions. 766 void free_collection_set(HeapRegion* cs_head); 767 768 // Abandon the current collection set without recording policy 769 // statistics or updating free lists. 770 void abandon_collection_set(HeapRegion* cs_head); 771 772 // Applies "scan_non_heap_roots" to roots outside the heap, 773 // "scan_rs" to roots inside the heap (having done "set_region" to 774 // indicate the region in which the root resides), and does "scan_perm" 775 // (setting the generation to the perm generation.) If "scan_rs" is 776 // NULL, then this step is skipped. The "worker_i" 777 // param is for use with parallel roots processing, and should be 778 // the "i" of the calling parallel worker thread's work(i) function. 779 // In the sequential case this param will be ignored. 780 void g1_process_strong_roots(bool collecting_perm_gen, 781 ScanningOption so, 782 OopClosure* scan_non_heap_roots, 783 OopsInHeapRegionClosure* scan_rs, 784 OopsInGenClosure* scan_perm, 785 int worker_i); 786 787 // Apply "blk" to all the weak roots of the system. These include 788 // JNI weak roots, the code cache, system dictionary, symbol table, 789 // string table, and referents of reachable weak refs. 790 void g1_process_weak_roots(OopClosure* root_closure, 791 OopClosure* non_root_closure); 792 793 // Frees a non-humongous region by initializing its contents and 794 // adding it to the free list that's passed as a parameter (this is 795 // usually a local list which will be appended to the master free 796 // list later). The used bytes of freed regions are accumulated in 797 // pre_used. If par is true, the region's RSet will not be freed 798 // up. The assumption is that this will be done later. 799 void free_region(HeapRegion* hr, 800 size_t* pre_used, 801 FreeRegionList* free_list, 802 bool par); 803 804 // Frees a humongous region by collapsing it into individual regions 805 // and calling free_region() for each of them. The freed regions 806 // will be added to the free list that's passed as a parameter (this 807 // is usually a local list which will be appended to the master free 808 // list later). The used bytes of freed regions are accumulated in 809 // pre_used. If par is true, the region's RSet will not be freed 810 // up. The assumption is that this will be done later. 811 void free_humongous_region(HeapRegion* hr, 812 size_t* pre_used, 813 FreeRegionList* free_list, 814 HumongousRegionSet* humongous_proxy_set, 815 bool par); 816 817 // Notifies all the necessary spaces that the committed space has 818 // been updated (either expanded or shrunk). It should be called 819 // after _g1_storage is updated. 820 void update_committed_space(HeapWord* old_end, HeapWord* new_end); 821 822 // The concurrent marker (and the thread it runs in.) 823 ConcurrentMark* _cm; 824 ConcurrentMarkThread* _cmThread; 825 bool _mark_in_progress; 826 827 // The concurrent refiner. 828 ConcurrentG1Refine* _cg1r; 829 830 // The parallel task queues 831 RefToScanQueueSet *_task_queues; 832 833 // True iff a evacuation has failed in the current collection. 834 bool _evacuation_failed; 835 836 // Set the attribute indicating whether evacuation has failed in the 837 // current collection. 838 void set_evacuation_failed(bool b) { _evacuation_failed = b; } 839 840 // Failed evacuations cause some logical from-space objects to have 841 // forwarding pointers to themselves. Reset them. 842 void remove_self_forwarding_pointers(); 843 844 // When one is non-null, so is the other. Together, they each pair is 845 // an object with a preserved mark, and its mark value. 846 GrowableArray<oop>* _objs_with_preserved_marks; 847 GrowableArray<markOop>* _preserved_marks_of_objs; 848 849 // Preserve the mark of "obj", if necessary, in preparation for its mark 850 // word being overwritten with a self-forwarding-pointer. 851 void preserve_mark_if_necessary(oop obj, markOop m); 852 853 // The stack of evac-failure objects left to be scanned. 854 GrowableArray<oop>* _evac_failure_scan_stack; 855 // The closure to apply to evac-failure objects. 856 857 OopsInHeapRegionClosure* _evac_failure_closure; 858 // Set the field above. 859 void 860 set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_closure) { 861 _evac_failure_closure = evac_failure_closure; 862 } 863 864 // Push "obj" on the scan stack. 865 void push_on_evac_failure_scan_stack(oop obj); 866 // Process scan stack entries until the stack is empty. 867 void drain_evac_failure_scan_stack(); 868 // True iff an invocation of "drain_scan_stack" is in progress; to 869 // prevent unnecessary recursion. 870 bool _drain_in_progress; 871 872 // Do any necessary initialization for evacuation-failure handling. 873 // "cl" is the closure that will be used to process evac-failure 874 // objects. 875 void init_for_evac_failure(OopsInHeapRegionClosure* cl); 876 // Do any necessary cleanup for evacuation-failure handling data 877 // structures. 878 void finalize_for_evac_failure(); 879 880 // An attempt to evacuate "obj" has failed; take necessary steps. 881 oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj); 882 void handle_evacuation_failure_common(oop obj, markOop m); 883 884 // ("Weak") Reference processing support. 885 // 886 // G1 has 2 instances of the referece processor class. One 887 // (_ref_processor_cm) handles reference object discovery 888 // and subsequent processing during concurrent marking cycles. 889 // 890 // The other (_ref_processor_stw) handles reference object 891 // discovery and processing during full GCs and incremental 892 // evacuation pauses. 893 // 894 // During an incremental pause, reference discovery will be 895 // temporarily disabled for _ref_processor_cm and will be 896 // enabled for _ref_processor_stw. At the end of the evacuation 897 // pause references discovered by _ref_processor_stw will be 898 // processed and discovery will be disabled. The previous 899 // setting for reference object discovery for _ref_processor_cm 900 // will be re-instated. 901 // 902 // At the start of marking: 903 // * Discovery by the CM ref processor is verified to be inactive 904 // and it's discovered lists are empty. 905 // * Discovery by the CM ref processor is then enabled. 906 // 907 // At the end of marking: 908 // * Any references on the CM ref processor's discovered 909 // lists are processed (possibly MT). 910 // 911 // At the start of full GC we: 912 // * Disable discovery by the CM ref processor and 913 // empty CM ref processor's discovered lists 914 // (without processing any entries). 915 // * Verify that the STW ref processor is inactive and it's 916 // discovered lists are empty. 917 // * Temporarily set STW ref processor discovery as single threaded. 918 // * Temporarily clear the STW ref processor's _is_alive_non_header 919 // field. 920 // * Finally enable discovery by the STW ref processor. 921 // 922 // The STW ref processor is used to record any discovered 923 // references during the full GC. 924 // 925 // At the end of a full GC we: 926 // * Enqueue any reference objects discovered by the STW ref processor 927 // that have non-live referents. This has the side-effect of 928 // making the STW ref processor inactive by disabling discovery. 929 // * Verify that the CM ref processor is still inactive 930 // and no references have been placed on it's discovered 931 // lists (also checked as a precondition during initial marking). 932 933 // The (stw) reference processor... 934 ReferenceProcessor* _ref_processor_stw; 935 936 // During reference object discovery, the _is_alive_non_header 937 // closure (if non-null) is applied to the referent object to 938 // determine whether the referent is live. If so then the 939 // reference object does not need to be 'discovered' and can 940 // be treated as a regular oop. This has the benefit of reducing 941 // the number of 'discovered' reference objects that need to 942 // be processed. 943 // 944 // Instance of the is_alive closure for embedding into the 945 // STW reference processor as the _is_alive_non_header field. 946 // Supplying a value for the _is_alive_non_header field is 947 // optional but doing so prevents unnecessary additions to 948 // the discovered lists during reference discovery. 949 G1STWIsAliveClosure _is_alive_closure_stw; 950 951 // The (concurrent marking) reference processor... 952 ReferenceProcessor* _ref_processor_cm; 953 954 // Instance of the concurrent mark is_alive closure for embedding 955 // into the Concurrent Marking reference processor as the 956 // _is_alive_non_header field. Supplying a value for the 957 // _is_alive_non_header field is optional but doing so prevents 958 // unnecessary additions to the discovered lists during reference 959 // discovery. 960 G1CMIsAliveClosure _is_alive_closure_cm; 961 962 // Cache used by G1CollectedHeap::start_cset_region_for_worker(). 963 HeapRegion** _worker_cset_start_region; 964 965 // Time stamp to validate the regions recorded in the cache 966 // used by G1CollectedHeap::start_cset_region_for_worker(). 967 // The heap region entry for a given worker is valid iff 968 // the associated time stamp value matches the current value 969 // of G1CollectedHeap::_gc_time_stamp. 970 unsigned int* _worker_cset_start_region_time_stamp; 971 972 enum G1H_process_strong_roots_tasks { 973 G1H_PS_filter_satb_buffers, 974 G1H_PS_refProcessor_oops_do, 975 // Leave this one last. 976 G1H_PS_NumElements 977 }; 978 979 SubTasksDone* _process_strong_tasks; 980 981 volatile bool _free_regions_coming; 982 983 public: 984 985 SubTasksDone* process_strong_tasks() { return _process_strong_tasks; } 986 987 void set_refine_cte_cl_concurrency(bool concurrent); 988 989 RefToScanQueue *task_queue(int i) const; 990 991 // A set of cards where updates happened during the GC 992 DirtyCardQueueSet& dirty_card_queue_set() { return _dirty_card_queue_set; } 993 994 // A DirtyCardQueueSet that is used to hold cards that contain 995 // references into the current collection set. This is used to 996 // update the remembered sets of the regions in the collection 997 // set in the event of an evacuation failure. 998 DirtyCardQueueSet& into_cset_dirty_card_queue_set() 999 { return _into_cset_dirty_card_queue_set; } 1000 1001 // Create a G1CollectedHeap with the specified policy. 1002 // Must call the initialize method afterwards. 1003 // May not return if something goes wrong. 1004 G1CollectedHeap(G1CollectorPolicy* policy); 1005 1006 // Initialize the G1CollectedHeap to have the initial and 1007 // maximum sizes, permanent generation, and remembered and barrier sets 1008 // specified by the policy object. 1009 jint initialize(); 1010 1011 // Initialize weak reference processing. 1012 virtual void ref_processing_init(); 1013 1014 void set_par_threads(uint t) { 1015 SharedHeap::set_par_threads(t); 1016 // Done in SharedHeap but oddly there are 1017 // two _process_strong_tasks's in a G1CollectedHeap 1018 // so do it here too. 1019 _process_strong_tasks->set_n_threads(t); 1020 } 1021 1022 // Set _n_par_threads according to a policy TBD. 1023 void set_par_threads(); 1024 1025 void set_n_termination(int t) { 1026 _process_strong_tasks->set_n_threads(t); 1027 } 1028 1029 virtual CollectedHeap::Name kind() const { 1030 return CollectedHeap::G1CollectedHeap; 1031 } 1032 1033 // The current policy object for the collector. 1034 G1CollectorPolicy* g1_policy() const { return _g1_policy; } 1035 1036 // Adaptive size policy. No such thing for g1. 1037 virtual AdaptiveSizePolicy* size_policy() { return NULL; } 1038 1039 // The rem set and barrier set. 1040 G1RemSet* g1_rem_set() const { return _g1_rem_set; } 1041 ModRefBarrierSet* mr_bs() const { return _mr_bs; } 1042 1043 // The rem set iterator. 1044 HeapRegionRemSetIterator* rem_set_iterator(int i) { 1045 return _rem_set_iterator[i]; 1046 } 1047 1048 HeapRegionRemSetIterator* rem_set_iterator() { 1049 return _rem_set_iterator[0]; 1050 } 1051 1052 unsigned get_gc_time_stamp() { 1053 return _gc_time_stamp; 1054 } 1055 1056 void reset_gc_time_stamp() { 1057 _gc_time_stamp = 0; 1058 OrderAccess::fence(); 1059 // Clear the cached CSet starting regions and time stamps. 1060 // Their validity is dependent on the GC timestamp. 1061 clear_cset_start_regions(); 1062 } 1063 1064 void increment_gc_time_stamp() { 1065 ++_gc_time_stamp; 1066 OrderAccess::fence(); 1067 } 1068 1069 void iterate_dirty_card_closure(CardTableEntryClosure* cl, 1070 DirtyCardQueue* into_cset_dcq, 1071 bool concurrent, int worker_i); 1072 1073 // The shared block offset table array. 1074 G1BlockOffsetSharedArray* bot_shared() const { return _bot_shared; } 1075 1076 // Reference Processing accessors 1077 1078 // The STW reference processor.... 1079 ReferenceProcessor* ref_processor_stw() const { return _ref_processor_stw; } 1080 1081 // The Concurent Marking reference processor... 1082 ReferenceProcessor* ref_processor_cm() const { return _ref_processor_cm; } 1083 1084 virtual size_t capacity() const; 1085 virtual size_t used() const; 1086 // This should be called when we're not holding the heap lock. The 1087 // result might be a bit inaccurate. 1088 size_t used_unlocked() const; 1089 size_t recalculate_used() const; 1090 1091 // These virtual functions do the actual allocation. 1092 // Some heaps may offer a contiguous region for shared non-blocking 1093 // allocation, via inlined code (by exporting the address of the top and 1094 // end fields defining the extent of the contiguous allocation region.) 1095 // But G1CollectedHeap doesn't yet support this. 1096 1097 // Return an estimate of the maximum allocation that could be performed 1098 // without triggering any collection or expansion activity. In a 1099 // generational collector, for example, this is probably the largest 1100 // allocation that could be supported (without expansion) in the youngest 1101 // generation. It is "unsafe" because no locks are taken; the result 1102 // should be treated as an approximation, not a guarantee, for use in 1103 // heuristic resizing decisions. 1104 virtual size_t unsafe_max_alloc(); 1105 1106 virtual bool is_maximal_no_gc() const { 1107 return _g1_storage.uncommitted_size() == 0; 1108 } 1109 1110 // The total number of regions in the heap. 1111 uint n_regions() { return _hrs.length(); } 1112 1113 // The max number of regions in the heap. 1114 uint max_regions() { return _hrs.max_length(); } 1115 1116 // The number of regions that are completely free. 1117 uint free_regions() { return _free_list.length(); } 1118 1119 // The number of regions that are not completely free. 1120 uint used_regions() { return n_regions() - free_regions(); } 1121 1122 // The number of regions available for "regular" expansion. 1123 uint expansion_regions() { return _expansion_regions; } 1124 1125 // Factory method for HeapRegion instances. It will return NULL if 1126 // the allocation fails. 1127 HeapRegion* new_heap_region(uint hrs_index, HeapWord* bottom); 1128 1129 void verify_not_dirty_region(HeapRegion* hr) PRODUCT_RETURN; 1130 void verify_dirty_region(HeapRegion* hr) PRODUCT_RETURN; 1131 void verify_dirty_young_list(HeapRegion* head) PRODUCT_RETURN; 1132 void verify_dirty_young_regions() PRODUCT_RETURN; 1133 1134 // verify_region_sets() performs verification over the region 1135 // lists. It will be compiled in the product code to be used when 1136 // necessary (i.e., during heap verification). 1137 void verify_region_sets(); 1138 1139 // verify_region_sets_optional() is planted in the code for 1140 // list verification in non-product builds (and it can be enabled in 1141 // product builds by definning HEAP_REGION_SET_FORCE_VERIFY to be 1). 1142 #if HEAP_REGION_SET_FORCE_VERIFY 1143 void verify_region_sets_optional() { 1144 verify_region_sets(); 1145 } 1146 #else // HEAP_REGION_SET_FORCE_VERIFY 1147 void verify_region_sets_optional() { } 1148 #endif // HEAP_REGION_SET_FORCE_VERIFY 1149 1150 #ifdef ASSERT 1151 bool is_on_master_free_list(HeapRegion* hr) { 1152 return hr->containing_set() == &_free_list; 1153 } 1154 1155 bool is_in_humongous_set(HeapRegion* hr) { 1156 return hr->containing_set() == &_humongous_set; 1157 } 1158 #endif // ASSERT 1159 1160 // Wrapper for the region list operations that can be called from 1161 // methods outside this class. 1162 1163 void secondary_free_list_add_as_tail(FreeRegionList* list) { 1164 _secondary_free_list.add_as_tail(list); 1165 } 1166 1167 void append_secondary_free_list() { 1168 _free_list.add_as_head(&_secondary_free_list); 1169 } 1170 1171 void append_secondary_free_list_if_not_empty_with_lock() { 1172 // If the secondary free list looks empty there's no reason to 1173 // take the lock and then try to append it. 1174 if (!_secondary_free_list.is_empty()) { 1175 MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag); 1176 append_secondary_free_list(); 1177 } 1178 } 1179 1180 void old_set_remove(HeapRegion* hr) { 1181 _old_set.remove(hr); 1182 } 1183 1184 size_t non_young_capacity_bytes() { 1185 return _old_set.total_capacity_bytes() + _humongous_set.total_capacity_bytes(); 1186 } 1187 1188 void set_free_regions_coming(); 1189 void reset_free_regions_coming(); 1190 bool free_regions_coming() { return _free_regions_coming; } 1191 void wait_while_free_regions_coming(); 1192 1193 // Determine whether the given region is one that we are using as an 1194 // old GC alloc region. 1195 bool is_old_gc_alloc_region(HeapRegion* hr) { 1196 return hr == _retained_old_gc_alloc_region; 1197 } 1198 1199 // Perform a collection of the heap; intended for use in implementing 1200 // "System.gc". This probably implies as full a collection as the 1201 // "CollectedHeap" supports. 1202 virtual void collect(GCCause::Cause cause); 1203 1204 // The same as above but assume that the caller holds the Heap_lock. 1205 void collect_locked(GCCause::Cause cause); 1206 1207 // This interface assumes that it's being called by the 1208 // vm thread. It collects the heap assuming that the 1209 // heap lock is already held and that we are executing in 1210 // the context of the vm thread. 1211 virtual void collect_as_vm_thread(GCCause::Cause cause); 1212 1213 // True iff a evacuation has failed in the most-recent collection. 1214 bool evacuation_failed() { return _evacuation_failed; } 1215 1216 // It will free a region if it has allocated objects in it that are 1217 // all dead. It calls either free_region() or 1218 // free_humongous_region() depending on the type of the region that 1219 // is passed to it. 1220 void free_region_if_empty(HeapRegion* hr, 1221 size_t* pre_used, 1222 FreeRegionList* free_list, 1223 OldRegionSet* old_proxy_set, 1224 HumongousRegionSet* humongous_proxy_set, 1225 HRRSCleanupTask* hrrs_cleanup_task, 1226 bool par); 1227 1228 // It appends the free list to the master free list and updates the 1229 // master humongous list according to the contents of the proxy 1230 // list. It also adjusts the total used bytes according to pre_used 1231 // (if par is true, it will do so by taking the ParGCRareEvent_lock). 1232 void update_sets_after_freeing_regions(size_t pre_used, 1233 FreeRegionList* free_list, 1234 OldRegionSet* old_proxy_set, 1235 HumongousRegionSet* humongous_proxy_set, 1236 bool par); 1237 1238 // Returns "TRUE" iff "p" points into the committed areas of the heap. 1239 virtual bool is_in(const void* p) const; 1240 1241 // Return "TRUE" iff the given object address is within the collection 1242 // set. 1243 inline bool obj_in_cs(oop obj); 1244 1245 // Return "TRUE" iff the given object address is in the reserved 1246 // region of g1 (excluding the permanent generation). 1247 bool is_in_g1_reserved(const void* p) const { 1248 return _g1_reserved.contains(p); 1249 } 1250 1251 // Returns a MemRegion that corresponds to the space that has been 1252 // reserved for the heap 1253 MemRegion g1_reserved() { 1254 return _g1_reserved; 1255 } 1256 1257 // Returns a MemRegion that corresponds to the space that has been 1258 // committed in the heap 1259 MemRegion g1_committed() { 1260 return _g1_committed; 1261 } 1262 1263 virtual bool is_in_closed_subset(const void* p) const; 1264 1265 // This resets the card table to all zeros. It is used after 1266 // a collection pause which used the card table to claim cards. 1267 void cleanUpCardTable(); 1268 1269 // Iteration functions. 1270 1271 // Iterate over all the ref-containing fields of all objects, calling 1272 // "cl.do_oop" on each. 1273 virtual void oop_iterate(OopClosure* cl) { 1274 oop_iterate(cl, true); 1275 } 1276 void oop_iterate(OopClosure* cl, bool do_perm); 1277 1278 // Same as above, restricted to a memory region. 1279 virtual void oop_iterate(MemRegion mr, OopClosure* cl) { 1280 oop_iterate(mr, cl, true); 1281 } 1282 void oop_iterate(MemRegion mr, OopClosure* cl, bool do_perm); 1283 1284 // Iterate over all objects, calling "cl.do_object" on each. 1285 virtual void object_iterate(ObjectClosure* cl) { 1286 object_iterate(cl, true); 1287 } 1288 virtual void safe_object_iterate(ObjectClosure* cl) { 1289 object_iterate(cl, true); 1290 } 1291 void object_iterate(ObjectClosure* cl, bool do_perm); 1292 1293 // Iterate over all objects allocated since the last collection, calling 1294 // "cl.do_object" on each. The heap must have been initialized properly 1295 // to support this function, or else this call will fail. 1296 virtual void object_iterate_since_last_GC(ObjectClosure* cl); 1297 1298 // Iterate over all spaces in use in the heap, in ascending address order. 1299 virtual void space_iterate(SpaceClosure* cl); 1300 1301 // Iterate over heap regions, in address order, terminating the 1302 // iteration early if the "doHeapRegion" method returns "true". 1303 void heap_region_iterate(HeapRegionClosure* blk) const; 1304 1305 // Iterate over heap regions starting with r (or the first region if "r" 1306 // is NULL), in address order, terminating early if the "doHeapRegion" 1307 // method returns "true". 1308 void heap_region_iterate_from(HeapRegion* r, HeapRegionClosure* blk) const; 1309 1310 // Return the region with the given index. It assumes the index is valid. 1311 HeapRegion* region_at(uint index) const { return _hrs.at(index); } 1312 1313 // Divide the heap region sequence into "chunks" of some size (the number 1314 // of regions divided by the number of parallel threads times some 1315 // overpartition factor, currently 4). Assumes that this will be called 1316 // in parallel by ParallelGCThreads worker threads with discinct worker 1317 // ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel 1318 // calls will use the same "claim_value", and that that claim value is 1319 // different from the claim_value of any heap region before the start of 1320 // the iteration. Applies "blk->doHeapRegion" to each of the regions, by 1321 // attempting to claim the first region in each chunk, and, if 1322 // successful, applying the closure to each region in the chunk (and 1323 // setting the claim value of the second and subsequent regions of the 1324 // chunk.) For now requires that "doHeapRegion" always returns "false", 1325 // i.e., that a closure never attempt to abort a traversal. 1326 void heap_region_par_iterate_chunked(HeapRegionClosure* blk, 1327 uint worker, 1328 uint no_of_par_workers, 1329 jint claim_value); 1330 1331 // It resets all the region claim values to the default. 1332 void reset_heap_region_claim_values(); 1333 1334 // Resets the claim values of regions in the current 1335 // collection set to the default. 1336 void reset_cset_heap_region_claim_values(); 1337 1338 #ifdef ASSERT 1339 bool check_heap_region_claim_values(jint claim_value); 1340 1341 // Same as the routine above but only checks regions in the 1342 // current collection set. 1343 bool check_cset_heap_region_claim_values(jint claim_value); 1344 #endif // ASSERT 1345 1346 // Clear the cached cset start regions and (more importantly) 1347 // the time stamps. Called when we reset the GC time stamp. 1348 void clear_cset_start_regions(); 1349 1350 // Given the id of a worker, obtain or calculate a suitable 1351 // starting region for iterating over the current collection set. 1352 HeapRegion* start_cset_region_for_worker(int worker_i); 1353 1354 // Iterate over the regions (if any) in the current collection set. 1355 void collection_set_iterate(HeapRegionClosure* blk); 1356 1357 // As above but starting from region r 1358 void collection_set_iterate_from(HeapRegion* r, HeapRegionClosure *blk); 1359 1360 // Returns the first (lowest address) compactible space in the heap. 1361 virtual CompactibleSpace* first_compactible_space(); 1362 1363 // A CollectedHeap will contain some number of spaces. This finds the 1364 // space containing a given address, or else returns NULL. 1365 virtual Space* space_containing(const void* addr) const; 1366 1367 // A G1CollectedHeap will contain some number of heap regions. This 1368 // finds the region containing a given address, or else returns NULL. 1369 template <class T> 1370 inline HeapRegion* heap_region_containing(const T addr) const; 1371 1372 // Like the above, but requires "addr" to be in the heap (to avoid a 1373 // null-check), and unlike the above, may return an continuing humongous 1374 // region. 1375 template <class T> 1376 inline HeapRegion* heap_region_containing_raw(const T addr) const; 1377 1378 // A CollectedHeap is divided into a dense sequence of "blocks"; that is, 1379 // each address in the (reserved) heap is a member of exactly 1380 // one block. The defining characteristic of a block is that it is 1381 // possible to find its size, and thus to progress forward to the next 1382 // block. (Blocks may be of different sizes.) Thus, blocks may 1383 // represent Java objects, or they might be free blocks in a 1384 // free-list-based heap (or subheap), as long as the two kinds are 1385 // distinguishable and the size of each is determinable. 1386 1387 // Returns the address of the start of the "block" that contains the 1388 // address "addr". We say "blocks" instead of "object" since some heaps 1389 // may not pack objects densely; a chunk may either be an object or a 1390 // non-object. 1391 virtual HeapWord* block_start(const void* addr) const; 1392 1393 // Requires "addr" to be the start of a chunk, and returns its size. 1394 // "addr + size" is required to be the start of a new chunk, or the end 1395 // of the active area of the heap. 1396 virtual size_t block_size(const HeapWord* addr) const; 1397 1398 // Requires "addr" to be the start of a block, and returns "TRUE" iff 1399 // the block is an object. 1400 virtual bool block_is_obj(const HeapWord* addr) const; 1401 1402 // Does this heap support heap inspection? (+PrintClassHistogram) 1403 virtual bool supports_heap_inspection() const { return true; } 1404 1405 // Section on thread-local allocation buffers (TLABs) 1406 // See CollectedHeap for semantics. 1407 1408 virtual bool supports_tlab_allocation() const; 1409 virtual size_t tlab_capacity(Thread* thr) const; 1410 virtual size_t unsafe_max_tlab_alloc(Thread* thr) const; 1411 1412 // Can a compiler initialize a new object without store barriers? 1413 // This permission only extends from the creation of a new object 1414 // via a TLAB up to the first subsequent safepoint. If such permission 1415 // is granted for this heap type, the compiler promises to call 1416 // defer_store_barrier() below on any slow path allocation of 1417 // a new object for which such initializing store barriers will 1418 // have been elided. G1, like CMS, allows this, but should be 1419 // ready to provide a compensating write barrier as necessary 1420 // if that storage came out of a non-young region. The efficiency 1421 // of this implementation depends crucially on being able to 1422 // answer very efficiently in constant time whether a piece of 1423 // storage in the heap comes from a young region or not. 1424 // See ReduceInitialCardMarks. 1425 virtual bool can_elide_tlab_store_barriers() const { 1426 return true; 1427 } 1428 1429 virtual bool card_mark_must_follow_store() const { 1430 return true; 1431 } 1432 1433 bool is_in_young(const oop obj) { 1434 HeapRegion* hr = heap_region_containing(obj); 1435 return hr != NULL && hr->is_young(); 1436 } 1437 1438 #ifdef ASSERT 1439 virtual bool is_in_partial_collection(const void* p); 1440 #endif 1441 1442 virtual bool is_scavengable(const void* addr); 1443 1444 // We don't need barriers for initializing stores to objects 1445 // in the young gen: for the SATB pre-barrier, there is no 1446 // pre-value that needs to be remembered; for the remembered-set 1447 // update logging post-barrier, we don't maintain remembered set 1448 // information for young gen objects. 1449 virtual bool can_elide_initializing_store_barrier(oop new_obj) { 1450 return is_in_young(new_obj); 1451 } 1452 1453 // Can a compiler elide a store barrier when it writes 1454 // a permanent oop into the heap? Applies when the compiler 1455 // is storing x to the heap, where x->is_perm() is true. 1456 virtual bool can_elide_permanent_oop_store_barriers() const { 1457 // At least until perm gen collection is also G1-ified, at 1458 // which point this should return false. 1459 return true; 1460 } 1461 1462 // Returns "true" iff the given word_size is "very large". 1463 static bool isHumongous(size_t word_size) { 1464 // Note this has to be strictly greater-than as the TLABs 1465 // are capped at the humongous thresold and we want to 1466 // ensure that we don't try to allocate a TLAB as 1467 // humongous and that we don't allocate a humongous 1468 // object in a TLAB. 1469 return word_size > _humongous_object_threshold_in_words; 1470 } 1471 1472 // Update mod union table with the set of dirty cards. 1473 void updateModUnion(); 1474 1475 // Set the mod union bits corresponding to the given memRegion. Note 1476 // that this is always a safe operation, since it doesn't clear any 1477 // bits. 1478 void markModUnionRange(MemRegion mr); 1479 1480 // Records the fact that a marking phase is no longer in progress. 1481 void set_marking_complete() { 1482 _mark_in_progress = false; 1483 } 1484 void set_marking_started() { 1485 _mark_in_progress = true; 1486 } 1487 bool mark_in_progress() { 1488 return _mark_in_progress; 1489 } 1490 1491 // Print the maximum heap capacity. 1492 virtual size_t max_capacity() const; 1493 1494 virtual jlong millis_since_last_gc(); 1495 1496 // Perform any cleanup actions necessary before allowing a verification. 1497 virtual void prepare_for_verify(); 1498 1499 // Perform verification. 1500 1501 // vo == UsePrevMarking -> use "prev" marking information, 1502 // vo == UseNextMarking -> use "next" marking information 1503 // vo == UseMarkWord -> use the mark word in the object header 1504 // 1505 // NOTE: Only the "prev" marking information is guaranteed to be 1506 // consistent most of the time, so most calls to this should use 1507 // vo == UsePrevMarking. 1508 // Currently, there is only one case where this is called with 1509 // vo == UseNextMarking, which is to verify the "next" marking 1510 // information at the end of remark. 1511 // Currently there is only one place where this is called with 1512 // vo == UseMarkWord, which is to verify the marking during a 1513 // full GC. 1514 void verify(bool silent, VerifyOption vo); 1515 1516 // Override; it uses the "prev" marking information 1517 virtual void verify(bool silent); 1518 virtual void print_on(outputStream* st) const; 1519 virtual void print_extended_on(outputStream* st) const; 1520 1521 virtual void print_gc_threads_on(outputStream* st) const; 1522 virtual void gc_threads_do(ThreadClosure* tc) const; 1523 1524 // Override 1525 void print_tracing_info() const; 1526 1527 // The following two methods are helpful for debugging RSet issues. 1528 void print_cset_rsets() PRODUCT_RETURN; 1529 void print_all_rsets() PRODUCT_RETURN; 1530 1531 // Convenience function to be used in situations where the heap type can be 1532 // asserted to be this type. 1533 static G1CollectedHeap* heap(); 1534 1535 void set_region_short_lived_locked(HeapRegion* hr); 1536 // add appropriate methods for any other surv rate groups 1537 1538 YoungList* young_list() { return _young_list; } 1539 1540 // debugging 1541 bool check_young_list_well_formed() { 1542 return _young_list->check_list_well_formed(); 1543 } 1544 1545 bool check_young_list_empty(bool check_heap, 1546 bool check_sample = true); 1547 1548 // *** Stuff related to concurrent marking. It's not clear to me that so 1549 // many of these need to be public. 1550 1551 // The functions below are helper functions that a subclass of 1552 // "CollectedHeap" can use in the implementation of its virtual 1553 // functions. 1554 // This performs a concurrent marking of the live objects in a 1555 // bitmap off to the side. 1556 void doConcurrentMark(); 1557 1558 bool isMarkedPrev(oop obj) const; 1559 bool isMarkedNext(oop obj) const; 1560 1561 // vo == UsePrevMarking -> use "prev" marking information, 1562 // vo == UseNextMarking -> use "next" marking information, 1563 // vo == UseMarkWord -> use mark word from object header 1564 bool is_obj_dead_cond(const oop obj, 1565 const HeapRegion* hr, 1566 const VerifyOption vo) const { 1567 1568 switch (vo) { 1569 case VerifyOption_G1UsePrevMarking: 1570 return is_obj_dead(obj, hr); 1571 case VerifyOption_G1UseNextMarking: 1572 return is_obj_ill(obj, hr); 1573 default: 1574 assert(vo == VerifyOption_G1UseMarkWord, "must be"); 1575 return !obj->is_gc_marked(); 1576 } 1577 } 1578 1579 // Determine if an object is dead, given the object and also 1580 // the region to which the object belongs. An object is dead 1581 // iff a) it was not allocated since the last mark and b) it 1582 // is not marked. 1583 1584 bool is_obj_dead(const oop obj, const HeapRegion* hr) const { 1585 return 1586 !hr->obj_allocated_since_prev_marking(obj) && 1587 !isMarkedPrev(obj); 1588 } 1589 1590 // This is used when copying an object to survivor space. 1591 // If the object is marked live, then we mark the copy live. 1592 // If the object is allocated since the start of this mark 1593 // cycle, then we mark the copy live. 1594 // If the object has been around since the previous mark 1595 // phase, and hasn't been marked yet during this phase, 1596 // then we don't mark it, we just wait for the 1597 // current marking cycle to get to it. 1598 1599 // This function returns true when an object has been 1600 // around since the previous marking and hasn't yet 1601 // been marked during this marking. 1602 1603 bool is_obj_ill(const oop obj, const HeapRegion* hr) const { 1604 return 1605 !hr->obj_allocated_since_next_marking(obj) && 1606 !isMarkedNext(obj); 1607 } 1608 1609 // Determine if an object is dead, given only the object itself. 1610 // This will find the region to which the object belongs and 1611 // then call the region version of the same function. 1612 1613 // Added if it is in permanent gen it isn't dead. 1614 // Added if it is NULL it isn't dead. 1615 1616 // vo == UsePrevMarking -> use "prev" marking information, 1617 // vo == UseNextMarking -> use "next" marking information, 1618 // vo == UseMarkWord -> use mark word from object header 1619 bool is_obj_dead_cond(const oop obj, 1620 const VerifyOption vo) const { 1621 1622 switch (vo) { 1623 case VerifyOption_G1UsePrevMarking: 1624 return is_obj_dead(obj); 1625 case VerifyOption_G1UseNextMarking: 1626 return is_obj_ill(obj); 1627 default: 1628 assert(vo == VerifyOption_G1UseMarkWord, "must be"); 1629 return !obj->is_gc_marked(); 1630 } 1631 } 1632 1633 bool is_obj_dead(const oop obj) const { 1634 const HeapRegion* hr = heap_region_containing(obj); 1635 if (hr == NULL) { 1636 if (Universe::heap()->is_in_permanent(obj)) 1637 return false; 1638 else if (obj == NULL) return false; 1639 else return true; 1640 } 1641 else return is_obj_dead(obj, hr); 1642 } 1643 1644 bool is_obj_ill(const oop obj) const { 1645 const HeapRegion* hr = heap_region_containing(obj); 1646 if (hr == NULL) { 1647 if (Universe::heap()->is_in_permanent(obj)) 1648 return false; 1649 else if (obj == NULL) return false; 1650 else return true; 1651 } 1652 else return is_obj_ill(obj, hr); 1653 } 1654 1655 // The following is just to alert the verification code 1656 // that a full collection has occurred and that the 1657 // remembered sets are no longer up to date. 1658 bool _full_collection; 1659 void set_full_collection() { _full_collection = true;} 1660 void clear_full_collection() {_full_collection = false;} 1661 bool full_collection() {return _full_collection;} 1662 1663 ConcurrentMark* concurrent_mark() const { return _cm; } 1664 ConcurrentG1Refine* concurrent_g1_refine() const { return _cg1r; } 1665 1666 // The dirty cards region list is used to record a subset of regions 1667 // whose cards need clearing. The list if populated during the 1668 // remembered set scanning and drained during the card table 1669 // cleanup. Although the methods are reentrant, population/draining 1670 // phases must not overlap. For synchronization purposes the last 1671 // element on the list points to itself. 1672 HeapRegion* _dirty_cards_region_list; 1673 void push_dirty_cards_region(HeapRegion* hr); 1674 HeapRegion* pop_dirty_cards_region(); 1675 1676 public: 1677 void stop_conc_gc_threads(); 1678 1679 size_t pending_card_num(); 1680 size_t max_pending_card_num(); 1681 size_t cards_scanned(); 1682 1683 protected: 1684 size_t _max_heap_capacity; 1685 }; 1686 1687 class G1ParGCAllocBuffer: public ParGCAllocBuffer { 1688 private: 1689 bool _retired; 1690 1691 public: 1692 G1ParGCAllocBuffer(size_t gclab_word_size); 1693 1694 void set_buf(HeapWord* buf) { 1695 ParGCAllocBuffer::set_buf(buf); 1696 _retired = false; 1697 } 1698 1699 void retire(bool end_of_gc, bool retain) { 1700 if (_retired) 1701 return; 1702 ParGCAllocBuffer::retire(end_of_gc, retain); 1703 _retired = true; 1704 } 1705 }; 1706 1707 class G1ParScanThreadState : public StackObj { 1708 protected: 1709 G1CollectedHeap* _g1h; 1710 RefToScanQueue* _refs; 1711 DirtyCardQueue _dcq; 1712 CardTableModRefBS* _ct_bs; 1713 G1RemSet* _g1_rem; 1714 1715 G1ParGCAllocBuffer _surviving_alloc_buffer; 1716 G1ParGCAllocBuffer _tenured_alloc_buffer; 1717 G1ParGCAllocBuffer* _alloc_buffers[GCAllocPurposeCount]; 1718 ageTable _age_table; 1719 1720 size_t _alloc_buffer_waste; 1721 size_t _undo_waste; 1722 1723 OopsInHeapRegionClosure* _evac_failure_cl; 1724 G1ParScanHeapEvacClosure* _evac_cl; 1725 G1ParScanPartialArrayClosure* _partial_scan_cl; 1726 1727 int _hash_seed; 1728 uint _queue_num; 1729 1730 size_t _term_attempts; 1731 1732 double _start; 1733 double _start_strong_roots; 1734 double _strong_roots_time; 1735 double _start_term; 1736 double _term_time; 1737 1738 // Map from young-age-index (0 == not young, 1 is youngest) to 1739 // surviving words. base is what we get back from the malloc call 1740 size_t* _surviving_young_words_base; 1741 // this points into the array, as we use the first few entries for padding 1742 size_t* _surviving_young_words; 1743 1744 #define PADDING_ELEM_NUM (DEFAULT_CACHE_LINE_SIZE / sizeof(size_t)) 1745 1746 void add_to_alloc_buffer_waste(size_t waste) { _alloc_buffer_waste += waste; } 1747 1748 void add_to_undo_waste(size_t waste) { _undo_waste += waste; } 1749 1750 DirtyCardQueue& dirty_card_queue() { return _dcq; } 1751 CardTableModRefBS* ctbs() { return _ct_bs; } 1752 1753 template <class T> void immediate_rs_update(HeapRegion* from, T* p, int tid) { 1754 if (!from->is_survivor()) { 1755 _g1_rem->par_write_ref(from, p, tid); 1756 } 1757 } 1758 1759 template <class T> void deferred_rs_update(HeapRegion* from, T* p, int tid) { 1760 // If the new value of the field points to the same region or 1761 // is the to-space, we don't need to include it in the Rset updates. 1762 if (!from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) && !from->is_survivor()) { 1763 size_t card_index = ctbs()->index_for(p); 1764 // If the card hasn't been added to the buffer, do it. 1765 if (ctbs()->mark_card_deferred(card_index)) { 1766 dirty_card_queue().enqueue((jbyte*)ctbs()->byte_for_index(card_index)); 1767 } 1768 } 1769 } 1770 1771 public: 1772 G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num); 1773 1774 ~G1ParScanThreadState() { 1775 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base); 1776 } 1777 1778 RefToScanQueue* refs() { return _refs; } 1779 ageTable* age_table() { return &_age_table; } 1780 1781 G1ParGCAllocBuffer* alloc_buffer(GCAllocPurpose purpose) { 1782 return _alloc_buffers[purpose]; 1783 } 1784 1785 size_t alloc_buffer_waste() const { return _alloc_buffer_waste; } 1786 size_t undo_waste() const { return _undo_waste; } 1787 1788 #ifdef ASSERT 1789 bool verify_ref(narrowOop* ref) const; 1790 bool verify_ref(oop* ref) const; 1791 bool verify_task(StarTask ref) const; 1792 #endif // ASSERT 1793 1794 template <class T> void push_on_queue(T* ref) { 1795 assert(verify_ref(ref), "sanity"); 1796 refs()->push(ref); 1797 } 1798 1799 template <class T> void update_rs(HeapRegion* from, T* p, int tid) { 1800 if (G1DeferredRSUpdate) { 1801 deferred_rs_update(from, p, tid); 1802 } else { 1803 immediate_rs_update(from, p, tid); 1804 } 1805 } 1806 1807 HeapWord* allocate_slow(GCAllocPurpose purpose, size_t word_sz) { 1808 1809 HeapWord* obj = NULL; 1810 size_t gclab_word_size = _g1h->desired_plab_sz(purpose); 1811 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) { 1812 G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose); 1813 assert(gclab_word_size == alloc_buf->word_sz(), 1814 "dynamic resizing is not supported"); 1815 add_to_alloc_buffer_waste(alloc_buf->words_remaining()); 1816 alloc_buf->retire(false, false); 1817 1818 HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size); 1819 if (buf == NULL) return NULL; // Let caller handle allocation failure. 1820 // Otherwise. 1821 alloc_buf->set_buf(buf); 1822 1823 obj = alloc_buf->allocate(word_sz); 1824 assert(obj != NULL, "buffer was definitely big enough..."); 1825 } else { 1826 obj = _g1h->par_allocate_during_gc(purpose, word_sz); 1827 } 1828 return obj; 1829 } 1830 1831 HeapWord* allocate(GCAllocPurpose purpose, size_t word_sz) { 1832 HeapWord* obj = alloc_buffer(purpose)->allocate(word_sz); 1833 if (obj != NULL) return obj; 1834 return allocate_slow(purpose, word_sz); 1835 } 1836 1837 void undo_allocation(GCAllocPurpose purpose, HeapWord* obj, size_t word_sz) { 1838 if (alloc_buffer(purpose)->contains(obj)) { 1839 assert(alloc_buffer(purpose)->contains(obj + word_sz - 1), 1840 "should contain whole object"); 1841 alloc_buffer(purpose)->undo_allocation(obj, word_sz); 1842 } else { 1843 CollectedHeap::fill_with_object(obj, word_sz); 1844 add_to_undo_waste(word_sz); 1845 } 1846 } 1847 1848 void set_evac_failure_closure(OopsInHeapRegionClosure* evac_failure_cl) { 1849 _evac_failure_cl = evac_failure_cl; 1850 } 1851 OopsInHeapRegionClosure* evac_failure_closure() { 1852 return _evac_failure_cl; 1853 } 1854 1855 void set_evac_closure(G1ParScanHeapEvacClosure* evac_cl) { 1856 _evac_cl = evac_cl; 1857 } 1858 1859 void set_partial_scan_closure(G1ParScanPartialArrayClosure* partial_scan_cl) { 1860 _partial_scan_cl = partial_scan_cl; 1861 } 1862 1863 int* hash_seed() { return &_hash_seed; } 1864 uint queue_num() { return _queue_num; } 1865 1866 size_t term_attempts() const { return _term_attempts; } 1867 void note_term_attempt() { _term_attempts++; } 1868 1869 void start_strong_roots() { 1870 _start_strong_roots = os::elapsedTime(); 1871 } 1872 void end_strong_roots() { 1873 _strong_roots_time += (os::elapsedTime() - _start_strong_roots); 1874 } 1875 double strong_roots_time() const { return _strong_roots_time; } 1876 1877 void start_term_time() { 1878 note_term_attempt(); 1879 _start_term = os::elapsedTime(); 1880 } 1881 void end_term_time() { 1882 _term_time += (os::elapsedTime() - _start_term); 1883 } 1884 double term_time() const { return _term_time; } 1885 1886 double elapsed_time() const { 1887 return os::elapsedTime() - _start; 1888 } 1889 1890 static void 1891 print_termination_stats_hdr(outputStream* const st = gclog_or_tty); 1892 void 1893 print_termination_stats(int i, outputStream* const st = gclog_or_tty) const; 1894 1895 size_t* surviving_young_words() { 1896 // We add on to hide entry 0 which accumulates surviving words for 1897 // age -1 regions (i.e. non-young ones) 1898 return _surviving_young_words; 1899 } 1900 1901 void retire_alloc_buffers() { 1902 for (int ap = 0; ap < GCAllocPurposeCount; ++ap) { 1903 size_t waste = _alloc_buffers[ap]->words_remaining(); 1904 add_to_alloc_buffer_waste(waste); 1905 _alloc_buffers[ap]->retire(true, false); 1906 } 1907 } 1908 1909 template <class T> void deal_with_reference(T* ref_to_scan) { 1910 if (has_partial_array_mask(ref_to_scan)) { 1911 _partial_scan_cl->do_oop_nv(ref_to_scan); 1912 } else { 1913 // Note: we can use "raw" versions of "region_containing" because 1914 // "obj_to_scan" is definitely in the heap, and is not in a 1915 // humongous region. 1916 HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan); 1917 _evac_cl->set_region(r); 1918 _evac_cl->do_oop_nv(ref_to_scan); 1919 } 1920 } 1921 1922 void deal_with_reference(StarTask ref) { 1923 assert(verify_task(ref), "sanity"); 1924 if (ref.is_narrow()) { 1925 deal_with_reference((narrowOop*)ref); 1926 } else { 1927 deal_with_reference((oop*)ref); 1928 } 1929 } 1930 1931 public: 1932 void trim_queue(); 1933 }; 1934 1935 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_HPP