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_HEAPREGION_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP 27 28 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" 29 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp" 30 #include "gc_implementation/g1/survRateGroup.hpp" 31 #include "gc_implementation/shared/ageTable.hpp" 32 #include "gc_implementation/shared/spaceDecorator.hpp" 33 #include "memory/space.inline.hpp" 34 #include "memory/watermark.hpp" 35 #include "utilities/macros.hpp" 36 37 #if INCLUDE_ALL_GCS 38 39 // A HeapRegion is the smallest piece of a G1CollectedHeap that 40 // can be collected independently. 41 42 // NOTE: Although a HeapRegion is a Space, its 43 // Space::initDirtyCardClosure method must not be called. 44 // The problem is that the existence of this method breaks 45 // the independence of barrier sets from remembered sets. 46 // The solution is to remove this method from the definition 47 // of a Space. 48 49 class CompactibleSpace; 50 class ContiguousSpace; 51 class HeapRegionRemSet; 52 class HeapRegionRemSetIterator; 53 class HeapRegion; 54 class HeapRegionSetBase; 55 56 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]" 57 #define HR_FORMAT_PARAMS(_hr_) \ 58 (_hr_)->hrs_index(), \ 59 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \ 60 (_hr_)->startsHumongous() ? "HS" : \ 61 (_hr_)->continuesHumongous() ? "HC" : \ 62 !(_hr_)->is_empty() ? "O" : "F", \ 63 (_hr_)->bottom(), (_hr_)->top(), (_hr_)->end() 64 65 // sentinel value for hrs_index 66 #define G1_NULL_HRS_INDEX ((uint) -1) 67 68 // A dirty card to oop closure for heap regions. It 69 // knows how to get the G1 heap and how to use the bitmap 70 // in the concurrent marker used by G1 to filter remembered 71 // sets. 72 73 class HeapRegionDCTOC : public ContiguousSpaceDCTOC { 74 public: 75 // Specification of possible DirtyCardToOopClosure filtering. 76 enum FilterKind { 77 NoFilterKind, 78 IntoCSFilterKind, 79 OutOfRegionFilterKind 80 }; 81 82 protected: 83 HeapRegion* _hr; 84 FilterKind _fk; 85 G1CollectedHeap* _g1; 86 87 void walk_mem_region_with_cl(MemRegion mr, 88 HeapWord* bottom, HeapWord* top, 89 ExtendedOopClosure* cl); 90 91 // We don't specialize this for FilteringClosure; filtering is handled by 92 // the "FilterKind" mechanism. But we provide this to avoid a compiler 93 // warning. 94 void walk_mem_region_with_cl(MemRegion mr, 95 HeapWord* bottom, HeapWord* top, 96 FilteringClosure* cl) { 97 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top, 98 (ExtendedOopClosure*)cl); 99 } 100 101 // Get the actual top of the area on which the closure will 102 // operate, given where the top is assumed to be (the end of the 103 // memory region passed to do_MemRegion) and where the object 104 // at the top is assumed to start. For example, an object may 105 // start at the top but actually extend past the assumed top, 106 // in which case the top becomes the end of the object. 107 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) { 108 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj); 109 } 110 111 // Walk the given memory region from bottom to (actual) top 112 // looking for objects and applying the oop closure (_cl) to 113 // them. The base implementation of this treats the area as 114 // blocks, where a block may or may not be an object. Sub- 115 // classes should override this to provide more accurate 116 // or possibly more efficient walking. 117 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) { 118 Filtering_DCTOC::walk_mem_region(mr, bottom, top); 119 } 120 121 public: 122 HeapRegionDCTOC(G1CollectedHeap* g1, 123 HeapRegion* hr, ExtendedOopClosure* cl, 124 CardTableModRefBS::PrecisionStyle precision, 125 FilterKind fk); 126 }; 127 128 // The complicating factor is that BlockOffsetTable diverged 129 // significantly, and we need functionality that is only in the G1 version. 130 // So I copied that code, which led to an alternate G1 version of 131 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 132 // be reconciled, then G1OffsetTableContigSpace could go away. 133 134 // The idea behind time stamps is the following. Doing a save_marks on 135 // all regions at every GC pause is time consuming (if I remember 136 // well, 10ms or so). So, we would like to do that only for regions 137 // that are GC alloc regions. To achieve this, we use time 138 // stamps. For every evacuation pause, G1CollectedHeap generates a 139 // unique time stamp (essentially a counter that gets 140 // incremented). Every time we want to call save_marks on a region, 141 // we set the saved_mark_word to top and also copy the current GC 142 // time stamp to the time stamp field of the space. Reading the 143 // saved_mark_word involves checking the time stamp of the 144 // region. If it is the same as the current GC time stamp, then we 145 // can safely read the saved_mark_word field, as it is valid. If the 146 // time stamp of the region is not the same as the current GC time 147 // stamp, then we instead read top, as the saved_mark_word field is 148 // invalid. Time stamps (on the regions and also on the 149 // G1CollectedHeap) are reset at every cleanup (we iterate over 150 // the regions anyway) and at the end of a Full GC. The current scheme 151 // that uses sequential unsigned ints will fail only if we have 4b 152 // evacuation pauses between two cleanups, which is _highly_ unlikely. 153 154 class G1OffsetTableContigSpace: public ContiguousSpace { 155 friend class VMStructs; 156 protected: 157 G1BlockOffsetArrayContigSpace _offsets; 158 Mutex _par_alloc_lock; 159 volatile unsigned _gc_time_stamp; 160 // When we need to retire an allocation region, while other threads 161 // are also concurrently trying to allocate into it, we typically 162 // allocate a dummy object at the end of the region to ensure that 163 // no more allocations can take place in it. However, sometimes we 164 // want to know where the end of the last "real" object we allocated 165 // into the region was and this is what this keeps track. 166 HeapWord* _pre_dummy_top; 167 168 public: 169 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 170 MemRegion mr); 171 172 void set_bottom(HeapWord* value); 173 void set_end(HeapWord* value); 174 175 virtual HeapWord* saved_mark_word() const; 176 virtual void set_saved_mark(); 177 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 178 unsigned get_gc_time_stamp() { return _gc_time_stamp; } 179 180 // See the comment above in the declaration of _pre_dummy_top for an 181 // explanation of what it is. 182 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 183 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 184 _pre_dummy_top = pre_dummy_top; 185 } 186 HeapWord* pre_dummy_top() { 187 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 188 } 189 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 190 191 virtual void clear(bool mangle_space); 192 193 HeapWord* block_start(const void* p); 194 HeapWord* block_start_const(const void* p) const; 195 196 // Add offset table update. 197 virtual HeapWord* allocate(size_t word_size); 198 HeapWord* par_allocate(size_t word_size); 199 200 // MarkSweep support phase3 201 virtual HeapWord* initialize_threshold(); 202 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 203 204 virtual void print() const; 205 206 void reset_bot() { 207 _offsets.zero_bottom_entry(); 208 _offsets.initialize_threshold(); 209 } 210 211 void update_bot_for_object(HeapWord* start, size_t word_size) { 212 _offsets.alloc_block(start, word_size); 213 } 214 215 void print_bot_on(outputStream* out) { 216 _offsets.print_on(out); 217 } 218 }; 219 220 class HeapRegion: public G1OffsetTableContigSpace { 221 friend class VMStructs; 222 private: 223 224 enum HumongousType { 225 NotHumongous = 0, 226 StartsHumongous, 227 ContinuesHumongous 228 }; 229 230 // Requires that the region "mr" be dense with objects, and begin and end 231 // with an object. 232 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl); 233 234 // The remembered set for this region. 235 // (Might want to make this "inline" later, to avoid some alloc failure 236 // issues.) 237 HeapRegionRemSet* _rem_set; 238 239 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 240 241 protected: 242 // The index of this region in the heap region sequence. 243 uint _hrs_index; 244 245 HumongousType _humongous_type; 246 // For a humongous region, region in which it starts. 247 HeapRegion* _humongous_start_region; 248 // For the start region of a humongous sequence, it's original end(). 249 HeapWord* _orig_end; 250 251 // True iff the region is in current collection_set. 252 bool _in_collection_set; 253 254 // True iff an attempt to evacuate an object in the region failed. 255 bool _evacuation_failed; 256 257 // A heap region may be a member one of a number of special subsets, each 258 // represented as linked lists through the field below. Currently, these 259 // sets include: 260 // The collection set. 261 // The set of allocation regions used in a collection pause. 262 // Spaces that may contain gray objects. 263 HeapRegion* _next_in_special_set; 264 265 // next region in the young "generation" region set 266 HeapRegion* _next_young_region; 267 268 // Next region whose cards need cleaning 269 HeapRegion* _next_dirty_cards_region; 270 271 // Fields used by the HeapRegionSetBase class and subclasses. 272 HeapRegion* _next; 273 #ifdef ASSERT 274 HeapRegionSetBase* _containing_set; 275 #endif // ASSERT 276 bool _pending_removal; 277 278 // For parallel heapRegion traversal. 279 jint _claimed; 280 281 // We use concurrent marking to determine the amount of live data 282 // in each heap region. 283 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 284 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 285 286 // The calculated GC efficiency of the region. 287 double _gc_efficiency; 288 289 enum YoungType { 290 NotYoung, // a region is not young 291 Young, // a region is young 292 Survivor // a region is young and it contains survivors 293 }; 294 295 volatile YoungType _young_type; 296 int _young_index_in_cset; 297 SurvRateGroup* _surv_rate_group; 298 int _age_index; 299 300 // The start of the unmarked area. The unmarked area extends from this 301 // word until the top and/or end of the region, and is the part 302 // of the region for which no marking was done, i.e. objects may 303 // have been allocated in this part since the last mark phase. 304 // "prev" is the top at the start of the last completed marking. 305 // "next" is the top at the start of the in-progress marking (if any.) 306 HeapWord* _prev_top_at_mark_start; 307 HeapWord* _next_top_at_mark_start; 308 // If a collection pause is in progress, this is the top at the start 309 // of that pause. 310 311 void init_top_at_mark_start() { 312 assert(_prev_marked_bytes == 0 && 313 _next_marked_bytes == 0, 314 "Must be called after zero_marked_bytes."); 315 HeapWord* bot = bottom(); 316 _prev_top_at_mark_start = bot; 317 _next_top_at_mark_start = bot; 318 } 319 320 void set_young_type(YoungType new_type) { 321 //assert(_young_type != new_type, "setting the same type" ); 322 // TODO: add more assertions here 323 _young_type = new_type; 324 } 325 326 // Cached attributes used in the collection set policy information 327 328 // The RSet length that was added to the total value 329 // for the collection set. 330 size_t _recorded_rs_length; 331 332 // The predicted elapsed time that was added to total value 333 // for the collection set. 334 double _predicted_elapsed_time_ms; 335 336 // The predicted number of bytes to copy that was added to 337 // the total value for the collection set. 338 size_t _predicted_bytes_to_copy; 339 340 public: 341 HeapRegion(uint hrs_index, 342 G1BlockOffsetSharedArray* sharedOffsetArray, 343 MemRegion mr); 344 345 static int LogOfHRGrainBytes; 346 static int LogOfHRGrainWords; 347 348 static size_t GrainBytes; 349 static size_t GrainWords; 350 static size_t CardsPerRegion; 351 352 static size_t align_up_to_region_byte_size(size_t sz) { 353 return (sz + (size_t) GrainBytes - 1) & 354 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 355 } 356 357 // It sets up the heap region size (GrainBytes / GrainWords), as 358 // well as other related fields that are based on the heap region 359 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 360 // CardsPerRegion). All those fields are considered constant 361 // throughout the JVM's execution, therefore they should only be set 362 // up once during initialization time. 363 static void setup_heap_region_size(uintx min_heap_size); 364 365 enum ClaimValues { 366 InitialClaimValue = 0, 367 FinalCountClaimValue = 1, 368 NoteEndClaimValue = 2, 369 ScrubRemSetClaimValue = 3, 370 ParVerifyClaimValue = 4, 371 RebuildRSClaimValue = 5, 372 ParEvacFailureClaimValue = 6, 373 AggregateCountClaimValue = 7, 374 VerifyCountClaimValue = 8 375 }; 376 377 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) { 378 assert(is_young(), "we can only skip BOT updates on young regions"); 379 return ContiguousSpace::par_allocate(word_size); 380 } 381 inline HeapWord* allocate_no_bot_updates(size_t word_size) { 382 assert(is_young(), "we can only skip BOT updates on young regions"); 383 return ContiguousSpace::allocate(word_size); 384 } 385 386 // If this region is a member of a HeapRegionSeq, the index in that 387 // sequence, otherwise -1. 388 uint hrs_index() const { return _hrs_index; } 389 390 // The number of bytes marked live in the region in the last marking phase. 391 size_t marked_bytes() { return _prev_marked_bytes; } 392 size_t live_bytes() { 393 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 394 } 395 396 // The number of bytes counted in the next marking. 397 size_t next_marked_bytes() { return _next_marked_bytes; } 398 // The number of bytes live wrt the next marking. 399 size_t next_live_bytes() { 400 return 401 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 402 } 403 404 // A lower bound on the amount of garbage bytes in the region. 405 size_t garbage_bytes() { 406 size_t used_at_mark_start_bytes = 407 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 408 assert(used_at_mark_start_bytes >= marked_bytes(), 409 "Can't mark more than we have."); 410 return used_at_mark_start_bytes - marked_bytes(); 411 } 412 413 // Return the amount of bytes we'll reclaim if we collect this 414 // region. This includes not only the known garbage bytes in the 415 // region but also any unallocated space in it, i.e., [top, end), 416 // since it will also be reclaimed if we collect the region. 417 size_t reclaimable_bytes() { 418 size_t known_live_bytes = live_bytes(); 419 assert(known_live_bytes <= capacity(), "sanity"); 420 return capacity() - known_live_bytes; 421 } 422 423 // An upper bound on the number of live bytes in the region. 424 size_t max_live_bytes() { return used() - garbage_bytes(); } 425 426 void add_to_marked_bytes(size_t incr_bytes) { 427 _next_marked_bytes = _next_marked_bytes + incr_bytes; 428 assert(_next_marked_bytes <= used(), "invariant" ); 429 } 430 431 void zero_marked_bytes() { 432 _prev_marked_bytes = _next_marked_bytes = 0; 433 } 434 435 bool isHumongous() const { return _humongous_type != NotHumongous; } 436 bool startsHumongous() const { return _humongous_type == StartsHumongous; } 437 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; } 438 // For a humongous region, region in which it starts. 439 HeapRegion* humongous_start_region() const { 440 return _humongous_start_region; 441 } 442 443 // Return the number of distinct regions that are covered by this region: 444 // 1 if the region is not humongous, >= 1 if the region is humongous. 445 uint region_num() const { 446 if (!isHumongous()) { 447 return 1U; 448 } else { 449 assert(startsHumongous(), "doesn't make sense on HC regions"); 450 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity"); 451 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes); 452 } 453 } 454 455 // Return the index + 1 of the last HC regions that's associated 456 // with this HS region. 457 uint last_hc_index() const { 458 assert(startsHumongous(), "don't call this otherwise"); 459 return hrs_index() + region_num(); 460 } 461 462 // Same as Space::is_in_reserved, but will use the original size of the region. 463 // The original size is different only for start humongous regions. They get 464 // their _end set up to be the end of the last continues region of the 465 // corresponding humongous object. 466 bool is_in_reserved_raw(const void* p) const { 467 return _bottom <= p && p < _orig_end; 468 } 469 470 // Makes the current region be a "starts humongous" region, i.e., 471 // the first region in a series of one or more contiguous regions 472 // that will contain a single "humongous" object. The two parameters 473 // are as follows: 474 // 475 // new_top : The new value of the top field of this region which 476 // points to the end of the humongous object that's being 477 // allocated. If there is more than one region in the series, top 478 // will lie beyond this region's original end field and on the last 479 // region in the series. 480 // 481 // new_end : The new value of the end field of this region which 482 // points to the end of the last region in the series. If there is 483 // one region in the series (namely: this one) end will be the same 484 // as the original end of this region. 485 // 486 // Updating top and end as described above makes this region look as 487 // if it spans the entire space taken up by all the regions in the 488 // series and an single allocation moved its top to new_top. This 489 // ensures that the space (capacity / allocated) taken up by all 490 // humongous regions can be calculated by just looking at the 491 // "starts humongous" regions and by ignoring the "continues 492 // humongous" regions. 493 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); 494 495 // Makes the current region be a "continues humongous' 496 // region. first_hr is the "start humongous" region of the series 497 // which this region will be part of. 498 void set_continuesHumongous(HeapRegion* first_hr); 499 500 // Unsets the humongous-related fields on the region. 501 void set_notHumongous(); 502 503 // If the region has a remembered set, return a pointer to it. 504 HeapRegionRemSet* rem_set() const { 505 return _rem_set; 506 } 507 508 // True iff the region is in current collection_set. 509 bool in_collection_set() const { 510 return _in_collection_set; 511 } 512 void set_in_collection_set(bool b) { 513 _in_collection_set = b; 514 } 515 HeapRegion* next_in_collection_set() { 516 assert(in_collection_set(), "should only invoke on member of CS."); 517 assert(_next_in_special_set == NULL || 518 _next_in_special_set->in_collection_set(), 519 "Malformed CS."); 520 return _next_in_special_set; 521 } 522 void set_next_in_collection_set(HeapRegion* r) { 523 assert(in_collection_set(), "should only invoke on member of CS."); 524 assert(r == NULL || r->in_collection_set(), "Malformed CS."); 525 _next_in_special_set = r; 526 } 527 528 // Methods used by the HeapRegionSetBase class and subclasses. 529 530 // Getter and setter for the next field used to link regions into 531 // linked lists. 532 HeapRegion* next() { return _next; } 533 534 void set_next(HeapRegion* next) { _next = next; } 535 536 // Every region added to a set is tagged with a reference to that 537 // set. This is used for doing consistency checking to make sure that 538 // the contents of a set are as they should be and it's only 539 // available in non-product builds. 540 #ifdef ASSERT 541 void set_containing_set(HeapRegionSetBase* containing_set) { 542 assert((containing_set == NULL && _containing_set != NULL) || 543 (containing_set != NULL && _containing_set == NULL), 544 err_msg("containing_set: "PTR_FORMAT" " 545 "_containing_set: "PTR_FORMAT, 546 containing_set, _containing_set)); 547 548 _containing_set = containing_set; 549 } 550 551 HeapRegionSetBase* containing_set() { return _containing_set; } 552 #else // ASSERT 553 void set_containing_set(HeapRegionSetBase* containing_set) { } 554 555 // containing_set() is only used in asserts so there's no reason 556 // to provide a dummy version of it. 557 #endif // ASSERT 558 559 // If we want to remove regions from a list in bulk we can simply tag 560 // them with the pending_removal tag and call the 561 // remove_all_pending() method on the list. 562 563 bool pending_removal() { return _pending_removal; } 564 565 void set_pending_removal(bool pending_removal) { 566 if (pending_removal) { 567 assert(!_pending_removal && containing_set() != NULL, 568 "can only set pending removal to true if it's false and " 569 "the region belongs to a region set"); 570 } else { 571 assert( _pending_removal && containing_set() == NULL, 572 "can only set pending removal to false if it's true and " 573 "the region does not belong to a region set"); 574 } 575 576 _pending_removal = pending_removal; 577 } 578 579 HeapRegion* get_next_young_region() { return _next_young_region; } 580 void set_next_young_region(HeapRegion* hr) { 581 _next_young_region = hr; 582 } 583 584 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 585 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 586 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 587 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 588 589 HeapWord* orig_end() { return _orig_end; } 590 591 // Allows logical separation between objects allocated before and after. 592 void save_marks(); 593 594 // Reset HR stuff to default values. 595 void hr_clear(bool par, bool clear_space); 596 void par_clear(); 597 598 // Get the start of the unmarked area in this region. 599 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 600 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 601 602 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects 603 // allocated in the current region before the last call to "save_mark". 604 void oop_before_save_marks_iterate(ExtendedOopClosure* cl); 605 606 // Note the start or end of marking. This tells the heap region 607 // that the collector is about to start or has finished (concurrently) 608 // marking the heap. 609 610 // Notify the region that concurrent marking is starting. Initialize 611 // all fields related to the next marking info. 612 inline void note_start_of_marking(); 613 614 // Notify the region that concurrent marking has finished. Copy the 615 // (now finalized) next marking info fields into the prev marking 616 // info fields. 617 inline void note_end_of_marking(); 618 619 // Notify the region that it will be used as to-space during a GC 620 // and we are about to start copying objects into it. 621 inline void note_start_of_copying(bool during_initial_mark); 622 623 // Notify the region that it ceases being to-space during a GC and 624 // we will not copy objects into it any more. 625 inline void note_end_of_copying(bool during_initial_mark); 626 627 // Notify the region that we are about to start processing 628 // self-forwarded objects during evac failure handling. 629 void note_self_forwarding_removal_start(bool during_initial_mark, 630 bool during_conc_mark); 631 632 // Notify the region that we have finished processing self-forwarded 633 // objects during evac failure handling. 634 void note_self_forwarding_removal_end(bool during_initial_mark, 635 bool during_conc_mark, 636 size_t marked_bytes); 637 638 // Returns "false" iff no object in the region was allocated when the 639 // last mark phase ended. 640 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 641 642 void reset_during_compaction() { 643 assert(isHumongous() && startsHumongous(), 644 "should only be called for starts humongous regions"); 645 646 zero_marked_bytes(); 647 init_top_at_mark_start(); 648 } 649 650 void calc_gc_efficiency(void); 651 double gc_efficiency() { return _gc_efficiency;} 652 653 bool is_young() const { return _young_type != NotYoung; } 654 bool is_survivor() const { return _young_type == Survivor; } 655 656 int young_index_in_cset() const { return _young_index_in_cset; } 657 void set_young_index_in_cset(int index) { 658 assert( (index == -1) || is_young(), "pre-condition" ); 659 _young_index_in_cset = index; 660 } 661 662 int age_in_surv_rate_group() { 663 assert( _surv_rate_group != NULL, "pre-condition" ); 664 assert( _age_index > -1, "pre-condition" ); 665 return _surv_rate_group->age_in_group(_age_index); 666 } 667 668 void record_surv_words_in_group(size_t words_survived) { 669 assert( _surv_rate_group != NULL, "pre-condition" ); 670 assert( _age_index > -1, "pre-condition" ); 671 int age_in_group = age_in_surv_rate_group(); 672 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 673 } 674 675 int age_in_surv_rate_group_cond() { 676 if (_surv_rate_group != NULL) 677 return age_in_surv_rate_group(); 678 else 679 return -1; 680 } 681 682 SurvRateGroup* surv_rate_group() { 683 return _surv_rate_group; 684 } 685 686 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 687 assert( surv_rate_group != NULL, "pre-condition" ); 688 assert( _surv_rate_group == NULL, "pre-condition" ); 689 assert( is_young(), "pre-condition" ); 690 691 _surv_rate_group = surv_rate_group; 692 _age_index = surv_rate_group->next_age_index(); 693 } 694 695 void uninstall_surv_rate_group() { 696 if (_surv_rate_group != NULL) { 697 assert( _age_index > -1, "pre-condition" ); 698 assert( is_young(), "pre-condition" ); 699 700 _surv_rate_group = NULL; 701 _age_index = -1; 702 } else { 703 assert( _age_index == -1, "pre-condition" ); 704 } 705 } 706 707 void set_young() { set_young_type(Young); } 708 709 void set_survivor() { set_young_type(Survivor); } 710 711 void set_not_young() { set_young_type(NotYoung); } 712 713 // Determine if an object has been allocated since the last 714 // mark performed by the collector. This returns true iff the object 715 // is within the unmarked area of the region. 716 bool obj_allocated_since_prev_marking(oop obj) const { 717 return (HeapWord *) obj >= prev_top_at_mark_start(); 718 } 719 bool obj_allocated_since_next_marking(oop obj) const { 720 return (HeapWord *) obj >= next_top_at_mark_start(); 721 } 722 723 // For parallel heapRegion traversal. 724 bool claimHeapRegion(int claimValue); 725 jint claim_value() { return _claimed; } 726 // Use this carefully: only when you're sure no one is claiming... 727 void set_claim_value(int claimValue) { _claimed = claimValue; } 728 729 // Returns the "evacuation_failed" property of the region. 730 bool evacuation_failed() { return _evacuation_failed; } 731 732 // Sets the "evacuation_failed" property of the region. 733 void set_evacuation_failed(bool b) { 734 _evacuation_failed = b; 735 736 if (b) { 737 _next_marked_bytes = 0; 738 } 739 } 740 741 // Requires that "mr" be entirely within the region. 742 // Apply "cl->do_object" to all objects that intersect with "mr". 743 // If the iteration encounters an unparseable portion of the region, 744 // or if "cl->abort()" is true after a closure application, 745 // terminate the iteration and return the address of the start of the 746 // subregion that isn't done. (The two can be distinguished by querying 747 // "cl->abort()".) Return of "NULL" indicates that the iteration 748 // completed. 749 HeapWord* 750 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 751 752 // filter_young: if true and the region is a young region then we 753 // skip the iteration. 754 // card_ptr: if not NULL, and we decide that the card is not young 755 // and we iterate over it, we'll clean the card before we start the 756 // iteration. 757 HeapWord* 758 oops_on_card_seq_iterate_careful(MemRegion mr, 759 FilterOutOfRegionClosure* cl, 760 bool filter_young, 761 jbyte* card_ptr); 762 763 // A version of block start that is guaranteed to find *some* block 764 // boundary at or before "p", but does not object iteration, and may 765 // therefore be used safely when the heap is unparseable. 766 HeapWord* block_start_careful(const void* p) const { 767 return _offsets.block_start_careful(p); 768 } 769 770 // Requires that "addr" is within the region. Returns the start of the 771 // first ("careful") block that starts at or after "addr", or else the 772 // "end" of the region if there is no such block. 773 HeapWord* next_block_start_careful(HeapWord* addr); 774 775 size_t recorded_rs_length() const { return _recorded_rs_length; } 776 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 777 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 778 779 void set_recorded_rs_length(size_t rs_length) { 780 _recorded_rs_length = rs_length; 781 } 782 783 void set_predicted_elapsed_time_ms(double ms) { 784 _predicted_elapsed_time_ms = ms; 785 } 786 787 void set_predicted_bytes_to_copy(size_t bytes) { 788 _predicted_bytes_to_copy = bytes; 789 } 790 791 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ 792 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); 793 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL) 794 795 virtual CompactibleSpace* next_compaction_space() const; 796 797 virtual void reset_after_compaction(); 798 799 void print() const; 800 void print_on(outputStream* st) const; 801 802 // vo == UsePrevMarking -> use "prev" marking information, 803 // vo == UseNextMarking -> use "next" marking information 804 // vo == UseMarkWord -> use the mark word in the object header 805 // 806 // NOTE: Only the "prev" marking information is guaranteed to be 807 // consistent most of the time, so most calls to this should use 808 // vo == UsePrevMarking. 809 // Currently, there is only one case where this is called with 810 // vo == UseNextMarking, which is to verify the "next" marking 811 // information at the end of remark. 812 // Currently there is only one place where this is called with 813 // vo == UseMarkWord, which is to verify the marking during a 814 // full GC. 815 void verify(VerifyOption vo, bool *failures) const; 816 817 // Override; it uses the "prev" marking information 818 virtual void verify() const; 819 }; 820 821 // HeapRegionClosure is used for iterating over regions. 822 // Terminates the iteration when the "doHeapRegion" method returns "true". 823 class HeapRegionClosure : public StackObj { 824 friend class HeapRegionSeq; 825 friend class G1CollectedHeap; 826 827 bool _complete; 828 void incomplete() { _complete = false; } 829 830 public: 831 HeapRegionClosure(): _complete(true) {} 832 833 // Typically called on each region until it returns true. 834 virtual bool doHeapRegion(HeapRegion* r) = 0; 835 836 // True after iteration if the closure was applied to all heap regions 837 // and returned "false" in all cases. 838 bool complete() { return _complete; } 839 }; 840 841 #endif // INCLUDE_ALL_GCS 842 843 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP