1 /* 2 * Copyright (c) 2001, 2014, 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 class nmethod; 56 57 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]" 58 #define HR_FORMAT_PARAMS(_hr_) \ 59 (_hr_)->hrs_index(), \ 60 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \ 61 (_hr_)->startsHumongous() ? "HS" : \ 62 (_hr_)->continuesHumongous() ? "HC" : \ 63 !(_hr_)->is_empty() ? "O" : "F", \ 64 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 65 66 // sentinel value for hrs_index 67 #define G1_NULL_HRS_INDEX ((uint) -1) 68 69 // A dirty card to oop closure for heap regions. It 70 // knows how to get the G1 heap and how to use the bitmap 71 // in the concurrent marker used by G1 to filter remembered 72 // sets. 73 74 class HeapRegionDCTOC : public DirtyCardToOopClosure { 75 public: 76 // Specification of possible DirtyCardToOopClosure filtering. 77 enum FilterKind { 78 NoFilterKind, 79 IntoCSFilterKind, 80 OutOfRegionFilterKind 81 }; 82 83 protected: 84 HeapRegion* _hr; 85 FilterKind _fk; 86 G1CollectedHeap* _g1; 87 88 // Walk the given memory region from bottom to (actual) top 89 // looking for objects and applying the oop closure (_cl) to 90 // them. The base implementation of this treats the area as 91 // blocks, where a block may or may not be an object. Sub- 92 // classes should override this to provide more accurate 93 // or possibly more efficient walking. 94 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); 95 96 public: 97 HeapRegionDCTOC(G1CollectedHeap* g1, 98 HeapRegion* hr, ExtendedOopClosure* cl, 99 CardTableModRefBS::PrecisionStyle precision, 100 FilterKind fk); 101 }; 102 103 // The complicating factor is that BlockOffsetTable diverged 104 // significantly, and we need functionality that is only in the G1 version. 105 // So I copied that code, which led to an alternate G1 version of 106 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 107 // be reconciled, then G1OffsetTableContigSpace could go away. 108 109 // The idea behind time stamps is the following. Doing a save_marks on 110 // all regions at every GC pause is time consuming (if I remember 111 // well, 10ms or so). So, we would like to do that only for regions 112 // that are GC alloc regions. To achieve this, we use time 113 // stamps. For every evacuation pause, G1CollectedHeap generates a 114 // unique time stamp (essentially a counter that gets 115 // incremented). Every time we want to call save_marks on a region, 116 // we set the saved_mark_word to top and also copy the current GC 117 // time stamp to the time stamp field of the space. Reading the 118 // saved_mark_word involves checking the time stamp of the 119 // region. If it is the same as the current GC time stamp, then we 120 // can safely read the saved_mark_word field, as it is valid. If the 121 // time stamp of the region is not the same as the current GC time 122 // stamp, then we instead read top, as the saved_mark_word field is 123 // invalid. Time stamps (on the regions and also on the 124 // G1CollectedHeap) are reset at every cleanup (we iterate over 125 // the regions anyway) and at the end of a Full GC. The current scheme 126 // that uses sequential unsigned ints will fail only if we have 4b 127 // evacuation pauses between two cleanups, which is _highly_ unlikely. 128 129 class G1OffsetTableContigSpace: public ContiguousSpace { 130 friend class VMStructs; 131 protected: 132 G1BlockOffsetArrayContigSpace _offsets; 133 Mutex _par_alloc_lock; 134 volatile unsigned _gc_time_stamp; 135 // When we need to retire an allocation region, while other threads 136 // are also concurrently trying to allocate into it, we typically 137 // allocate a dummy object at the end of the region to ensure that 138 // no more allocations can take place in it. However, sometimes we 139 // want to know where the end of the last "real" object we allocated 140 // into the region was and this is what this keeps track. 141 HeapWord* _pre_dummy_top; 142 143 public: 144 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 145 MemRegion mr); 146 147 void set_bottom(HeapWord* value); 148 void set_end(HeapWord* value); 149 150 virtual HeapWord* saved_mark_word() const; 151 void record_top_and_timestamp(); 152 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 153 unsigned get_gc_time_stamp() { return _gc_time_stamp; } 154 155 // See the comment above in the declaration of _pre_dummy_top for an 156 // explanation of what it is. 157 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 158 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 159 _pre_dummy_top = pre_dummy_top; 160 } 161 HeapWord* pre_dummy_top() { 162 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 163 } 164 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 165 166 virtual void clear(bool mangle_space); 167 168 HeapWord* block_start(const void* p); 169 HeapWord* block_start_const(const void* p) const; 170 171 // Add offset table update. 172 virtual HeapWord* allocate(size_t word_size); 173 HeapWord* par_allocate(size_t word_size); 174 175 // MarkSweep support phase3 176 virtual HeapWord* initialize_threshold(); 177 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 178 179 virtual void print() const; 180 181 void reset_bot() { 182 _offsets.zero_bottom_entry(); 183 _offsets.initialize_threshold(); 184 } 185 186 void update_bot_for_object(HeapWord* start, size_t word_size) { 187 _offsets.alloc_block(start, word_size); 188 } 189 190 void print_bot_on(outputStream* out) { 191 _offsets.print_on(out); 192 } 193 }; 194 195 class HeapRegion: public G1OffsetTableContigSpace { 196 friend class VMStructs; 197 private: 198 199 enum HumongousType { 200 NotHumongous = 0, 201 StartsHumongous, 202 ContinuesHumongous 203 }; 204 205 // Requires that the region "mr" be dense with objects, and begin and end 206 // with an object. 207 void oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl); 208 209 // The remembered set for this region. 210 // (Might want to make this "inline" later, to avoid some alloc failure 211 // issues.) 212 HeapRegionRemSet* _rem_set; 213 214 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 215 216 protected: 217 // The index of this region in the heap region sequence. 218 uint _hrs_index; 219 220 HumongousType _humongous_type; 221 // For a humongous region, region in which it starts. 222 HeapRegion* _humongous_start_region; 223 // For the start region of a humongous sequence, it's original end(). 224 HeapWord* _orig_end; 225 226 // True iff the region is in current collection_set. 227 bool _in_collection_set; 228 229 // True iff an attempt to evacuate an object in the region failed. 230 bool _evacuation_failed; 231 232 // A heap region may be a member one of a number of special subsets, each 233 // represented as linked lists through the field below. Currently, these 234 // sets include: 235 // The collection set. 236 // The set of allocation regions used in a collection pause. 237 // Spaces that may contain gray objects. 238 HeapRegion* _next_in_special_set; 239 240 // next region in the young "generation" region set 241 HeapRegion* _next_young_region; 242 243 // Next region whose cards need cleaning 244 HeapRegion* _next_dirty_cards_region; 245 246 // Fields used by the HeapRegionSetBase class and subclasses. 247 HeapRegion* _next; 248 HeapRegion* _prev; 249 #ifdef ASSERT 250 HeapRegionSetBase* _containing_set; 251 #endif // ASSERT 252 bool _pending_removal; 253 254 // For parallel heapRegion traversal. 255 jint _claimed; 256 257 // We use concurrent marking to determine the amount of live data 258 // in each heap region. 259 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 260 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 261 262 // The calculated GC efficiency of the region. 263 double _gc_efficiency; 264 265 enum YoungType { 266 NotYoung, // a region is not young 267 Young, // a region is young 268 Survivor // a region is young and it contains survivors 269 }; 270 271 volatile YoungType _young_type; 272 int _young_index_in_cset; 273 SurvRateGroup* _surv_rate_group; 274 int _age_index; 275 276 // The start of the unmarked area. The unmarked area extends from this 277 // word until the top and/or end of the region, and is the part 278 // of the region for which no marking was done, i.e. objects may 279 // have been allocated in this part since the last mark phase. 280 // "prev" is the top at the start of the last completed marking. 281 // "next" is the top at the start of the in-progress marking (if any.) 282 HeapWord* _prev_top_at_mark_start; 283 HeapWord* _next_top_at_mark_start; 284 // If a collection pause is in progress, this is the top at the start 285 // of that pause. 286 287 void init_top_at_mark_start() { 288 assert(_prev_marked_bytes == 0 && 289 _next_marked_bytes == 0, 290 "Must be called after zero_marked_bytes."); 291 HeapWord* bot = bottom(); 292 _prev_top_at_mark_start = bot; 293 _next_top_at_mark_start = bot; 294 } 295 296 void set_young_type(YoungType new_type) { 297 //assert(_young_type != new_type, "setting the same type" ); 298 // TODO: add more assertions here 299 _young_type = new_type; 300 } 301 302 // Cached attributes used in the collection set policy information 303 304 // The RSet length that was added to the total value 305 // for the collection set. 306 size_t _recorded_rs_length; 307 308 // The predicted elapsed time that was added to total value 309 // for the collection set. 310 double _predicted_elapsed_time_ms; 311 312 // The predicted number of bytes to copy that was added to 313 // the total value for the collection set. 314 size_t _predicted_bytes_to_copy; 315 316 public: 317 HeapRegion(uint hrs_index, 318 G1BlockOffsetSharedArray* sharedOffsetArray, 319 MemRegion mr); 320 321 static int LogOfHRGrainBytes; 322 static int LogOfHRGrainWords; 323 324 static size_t GrainBytes; 325 static size_t GrainWords; 326 static size_t CardsPerRegion; 327 328 static size_t align_up_to_region_byte_size(size_t sz) { 329 return (sz + (size_t) GrainBytes - 1) & 330 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 331 } 332 333 static size_t max_region_size(); 334 335 // It sets up the heap region size (GrainBytes / GrainWords), as 336 // well as other related fields that are based on the heap region 337 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 338 // CardsPerRegion). All those fields are considered constant 339 // throughout the JVM's execution, therefore they should only be set 340 // up once during initialization time. 341 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); 342 343 enum ClaimValues { 344 InitialClaimValue = 0, 345 FinalCountClaimValue = 1, 346 NoteEndClaimValue = 2, 347 ScrubRemSetClaimValue = 3, 348 ParVerifyClaimValue = 4, 349 RebuildRSClaimValue = 5, 350 ParEvacFailureClaimValue = 6, 351 AggregateCountClaimValue = 7, 352 VerifyCountClaimValue = 8, 353 ParMarkRootClaimValue = 9 354 }; 355 356 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) { 357 assert(is_young(), "we can only skip BOT updates on young regions"); 358 return ContiguousSpace::par_allocate(word_size); 359 } 360 inline HeapWord* allocate_no_bot_updates(size_t word_size) { 361 assert(is_young(), "we can only skip BOT updates on young regions"); 362 return ContiguousSpace::allocate(word_size); 363 } 364 365 // If this region is a member of a HeapRegionSeq, the index in that 366 // sequence, otherwise -1. 367 uint hrs_index() const { return _hrs_index; } 368 369 // The number of bytes marked live in the region in the last marking phase. 370 size_t marked_bytes() { return _prev_marked_bytes; } 371 size_t live_bytes() { 372 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 373 } 374 375 // The number of bytes counted in the next marking. 376 size_t next_marked_bytes() { return _next_marked_bytes; } 377 // The number of bytes live wrt the next marking. 378 size_t next_live_bytes() { 379 return 380 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 381 } 382 383 // A lower bound on the amount of garbage bytes in the region. 384 size_t garbage_bytes() { 385 size_t used_at_mark_start_bytes = 386 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 387 assert(used_at_mark_start_bytes >= marked_bytes(), 388 "Can't mark more than we have."); 389 return used_at_mark_start_bytes - marked_bytes(); 390 } 391 392 // Return the amount of bytes we'll reclaim if we collect this 393 // region. This includes not only the known garbage bytes in the 394 // region but also any unallocated space in it, i.e., [top, end), 395 // since it will also be reclaimed if we collect the region. 396 size_t reclaimable_bytes() { 397 size_t known_live_bytes = live_bytes(); 398 assert(known_live_bytes <= capacity(), "sanity"); 399 return capacity() - known_live_bytes; 400 } 401 402 // An upper bound on the number of live bytes in the region. 403 size_t max_live_bytes() { return used() - garbage_bytes(); } 404 405 void add_to_marked_bytes(size_t incr_bytes) { 406 _next_marked_bytes = _next_marked_bytes + incr_bytes; 407 assert(_next_marked_bytes <= used(), "invariant" ); 408 } 409 410 void zero_marked_bytes() { 411 _prev_marked_bytes = _next_marked_bytes = 0; 412 } 413 414 bool isHumongous() const { return _humongous_type != NotHumongous; } 415 bool startsHumongous() const { return _humongous_type == StartsHumongous; } 416 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; } 417 // For a humongous region, region in which it starts. 418 HeapRegion* humongous_start_region() const { 419 return _humongous_start_region; 420 } 421 422 // Return the number of distinct regions that are covered by this region: 423 // 1 if the region is not humongous, >= 1 if the region is humongous. 424 uint region_num() const { 425 if (!isHumongous()) { 426 return 1U; 427 } else { 428 assert(startsHumongous(), "doesn't make sense on HC regions"); 429 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity"); 430 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes); 431 } 432 } 433 434 // Return the index + 1 of the last HC regions that's associated 435 // with this HS region. 436 uint last_hc_index() const { 437 assert(startsHumongous(), "don't call this otherwise"); 438 return hrs_index() + region_num(); 439 } 440 441 // Same as Space::is_in_reserved, but will use the original size of the region. 442 // The original size is different only for start humongous regions. They get 443 // their _end set up to be the end of the last continues region of the 444 // corresponding humongous object. 445 bool is_in_reserved_raw(const void* p) const { 446 return _bottom <= p && p < _orig_end; 447 } 448 449 // Makes the current region be a "starts humongous" region, i.e., 450 // the first region in a series of one or more contiguous regions 451 // that will contain a single "humongous" object. The two parameters 452 // are as follows: 453 // 454 // new_top : The new value of the top field of this region which 455 // points to the end of the humongous object that's being 456 // allocated. If there is more than one region in the series, top 457 // will lie beyond this region's original end field and on the last 458 // region in the series. 459 // 460 // new_end : The new value of the end field of this region which 461 // points to the end of the last region in the series. If there is 462 // one region in the series (namely: this one) end will be the same 463 // as the original end of this region. 464 // 465 // Updating top and end as described above makes this region look as 466 // if it spans the entire space taken up by all the regions in the 467 // series and an single allocation moved its top to new_top. This 468 // ensures that the space (capacity / allocated) taken up by all 469 // humongous regions can be calculated by just looking at the 470 // "starts humongous" regions and by ignoring the "continues 471 // humongous" regions. 472 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); 473 474 // Makes the current region be a "continues humongous' 475 // region. first_hr is the "start humongous" region of the series 476 // which this region will be part of. 477 void set_continuesHumongous(HeapRegion* first_hr); 478 479 // Unsets the humongous-related fields on the region. 480 void set_notHumongous(); 481 482 // If the region has a remembered set, return a pointer to it. 483 HeapRegionRemSet* rem_set() const { 484 return _rem_set; 485 } 486 487 // True iff the region is in current collection_set. 488 bool in_collection_set() const { 489 return _in_collection_set; 490 } 491 void set_in_collection_set(bool b) { 492 _in_collection_set = b; 493 } 494 HeapRegion* next_in_collection_set() { 495 assert(in_collection_set(), "should only invoke on member of CS."); 496 assert(_next_in_special_set == NULL || 497 _next_in_special_set->in_collection_set(), 498 "Malformed CS."); 499 return _next_in_special_set; 500 } 501 void set_next_in_collection_set(HeapRegion* r) { 502 assert(in_collection_set(), "should only invoke on member of CS."); 503 assert(r == NULL || r->in_collection_set(), "Malformed CS."); 504 _next_in_special_set = r; 505 } 506 507 // Methods used by the HeapRegionSetBase class and subclasses. 508 509 // Getter and setter for the next and prev fields used to link regions into 510 // linked lists. 511 HeapRegion* next() { return _next; } 512 HeapRegion* prev() { return _prev; } 513 514 void set_next(HeapRegion* next) { _next = next; } 515 void set_prev(HeapRegion* prev) { _prev = prev; } 516 517 // Every region added to a set is tagged with a reference to that 518 // set. This is used for doing consistency checking to make sure that 519 // the contents of a set are as they should be and it's only 520 // available in non-product builds. 521 #ifdef ASSERT 522 void set_containing_set(HeapRegionSetBase* containing_set) { 523 assert((containing_set == NULL && _containing_set != NULL) || 524 (containing_set != NULL && _containing_set == NULL), 525 err_msg("containing_set: "PTR_FORMAT" " 526 "_containing_set: "PTR_FORMAT, 527 p2i(containing_set), p2i(_containing_set))); 528 529 _containing_set = containing_set; 530 } 531 532 HeapRegionSetBase* containing_set() { return _containing_set; } 533 #else // ASSERT 534 void set_containing_set(HeapRegionSetBase* containing_set) { } 535 536 // containing_set() is only used in asserts so there's no reason 537 // to provide a dummy version of it. 538 #endif // ASSERT 539 540 // If we want to remove regions from a list in bulk we can simply tag 541 // them with the pending_removal tag and call the 542 // remove_all_pending() method on the list. 543 544 bool pending_removal() { return _pending_removal; } 545 546 void set_pending_removal(bool pending_removal) { 547 if (pending_removal) { 548 assert(!_pending_removal && containing_set() != NULL, 549 "can only set pending removal to true if it's false and " 550 "the region belongs to a region set"); 551 } else { 552 assert( _pending_removal && containing_set() == NULL, 553 "can only set pending removal to false if it's true and " 554 "the region does not belong to a region set"); 555 } 556 557 _pending_removal = pending_removal; 558 } 559 560 HeapRegion* get_next_young_region() { return _next_young_region; } 561 void set_next_young_region(HeapRegion* hr) { 562 _next_young_region = hr; 563 } 564 565 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 566 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 567 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 568 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 569 570 HeapWord* orig_end() { return _orig_end; } 571 572 // Allows logical separation between objects allocated before and after. 573 void save_marks(); 574 575 // Reset HR stuff to default values. 576 void hr_clear(bool par, bool clear_space, bool locked = false); 577 void par_clear(); 578 579 // Get the start of the unmarked area in this region. 580 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 581 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 582 583 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects 584 // allocated in the current region before the last call to "save_mark". 585 void oop_before_save_marks_iterate(ExtendedOopClosure* cl); 586 587 // Note the start or end of marking. This tells the heap region 588 // that the collector is about to start or has finished (concurrently) 589 // marking the heap. 590 591 // Notify the region that concurrent marking is starting. Initialize 592 // all fields related to the next marking info. 593 inline void note_start_of_marking(); 594 595 // Notify the region that concurrent marking has finished. Copy the 596 // (now finalized) next marking info fields into the prev marking 597 // info fields. 598 inline void note_end_of_marking(); 599 600 // Notify the region that it will be used as to-space during a GC 601 // and we are about to start copying objects into it. 602 inline void note_start_of_copying(bool during_initial_mark); 603 604 // Notify the region that it ceases being to-space during a GC and 605 // we will not copy objects into it any more. 606 inline void note_end_of_copying(bool during_initial_mark); 607 608 // Notify the region that we are about to start processing 609 // self-forwarded objects during evac failure handling. 610 void note_self_forwarding_removal_start(bool during_initial_mark, 611 bool during_conc_mark); 612 613 // Notify the region that we have finished processing self-forwarded 614 // objects during evac failure handling. 615 void note_self_forwarding_removal_end(bool during_initial_mark, 616 bool during_conc_mark, 617 size_t marked_bytes); 618 619 // Returns "false" iff no object in the region was allocated when the 620 // last mark phase ended. 621 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 622 623 void reset_during_compaction() { 624 assert(isHumongous() && startsHumongous(), 625 "should only be called for starts humongous regions"); 626 627 zero_marked_bytes(); 628 init_top_at_mark_start(); 629 } 630 631 void calc_gc_efficiency(void); 632 double gc_efficiency() { return _gc_efficiency;} 633 634 bool is_young() const { return _young_type != NotYoung; } 635 bool is_survivor() const { return _young_type == Survivor; } 636 637 int young_index_in_cset() const { return _young_index_in_cset; } 638 void set_young_index_in_cset(int index) { 639 assert( (index == -1) || is_young(), "pre-condition" ); 640 _young_index_in_cset = index; 641 } 642 643 int age_in_surv_rate_group() { 644 assert( _surv_rate_group != NULL, "pre-condition" ); 645 assert( _age_index > -1, "pre-condition" ); 646 return _surv_rate_group->age_in_group(_age_index); 647 } 648 649 void record_surv_words_in_group(size_t words_survived) { 650 assert( _surv_rate_group != NULL, "pre-condition" ); 651 assert( _age_index > -1, "pre-condition" ); 652 int age_in_group = age_in_surv_rate_group(); 653 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 654 } 655 656 int age_in_surv_rate_group_cond() { 657 if (_surv_rate_group != NULL) 658 return age_in_surv_rate_group(); 659 else 660 return -1; 661 } 662 663 SurvRateGroup* surv_rate_group() { 664 return _surv_rate_group; 665 } 666 667 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 668 assert( surv_rate_group != NULL, "pre-condition" ); 669 assert( _surv_rate_group == NULL, "pre-condition" ); 670 assert( is_young(), "pre-condition" ); 671 672 _surv_rate_group = surv_rate_group; 673 _age_index = surv_rate_group->next_age_index(); 674 } 675 676 void uninstall_surv_rate_group() { 677 if (_surv_rate_group != NULL) { 678 assert( _age_index > -1, "pre-condition" ); 679 assert( is_young(), "pre-condition" ); 680 681 _surv_rate_group = NULL; 682 _age_index = -1; 683 } else { 684 assert( _age_index == -1, "pre-condition" ); 685 } 686 } 687 688 void set_young() { set_young_type(Young); } 689 690 void set_survivor() { set_young_type(Survivor); } 691 692 void set_not_young() { set_young_type(NotYoung); } 693 694 // Determine if an object has been allocated since the last 695 // mark performed by the collector. This returns true iff the object 696 // is within the unmarked area of the region. 697 bool obj_allocated_since_prev_marking(oop obj) const { 698 return (HeapWord *) obj >= prev_top_at_mark_start(); 699 } 700 bool obj_allocated_since_next_marking(oop obj) const { 701 return (HeapWord *) obj >= next_top_at_mark_start(); 702 } 703 704 // For parallel heapRegion traversal. 705 bool claimHeapRegion(int claimValue); 706 jint claim_value() { return _claimed; } 707 // Use this carefully: only when you're sure no one is claiming... 708 void set_claim_value(int claimValue) { _claimed = claimValue; } 709 710 // Returns the "evacuation_failed" property of the region. 711 bool evacuation_failed() { return _evacuation_failed; } 712 713 // Sets the "evacuation_failed" property of the region. 714 void set_evacuation_failed(bool b) { 715 _evacuation_failed = b; 716 717 if (b) { 718 _next_marked_bytes = 0; 719 } 720 } 721 722 // Requires that "mr" be entirely within the region. 723 // Apply "cl->do_object" to all objects that intersect with "mr". 724 // If the iteration encounters an unparseable portion of the region, 725 // or if "cl->abort()" is true after a closure application, 726 // terminate the iteration and return the address of the start of the 727 // subregion that isn't done. (The two can be distinguished by querying 728 // "cl->abort()".) Return of "NULL" indicates that the iteration 729 // completed. 730 HeapWord* 731 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 732 733 // filter_young: if true and the region is a young region then we 734 // skip the iteration. 735 // card_ptr: if not NULL, and we decide that the card is not young 736 // and we iterate over it, we'll clean the card before we start the 737 // iteration. 738 HeapWord* 739 oops_on_card_seq_iterate_careful(MemRegion mr, 740 FilterOutOfRegionClosure* cl, 741 bool filter_young, 742 jbyte* card_ptr); 743 744 // A version of block start that is guaranteed to find *some* block 745 // boundary at or before "p", but does not object iteration, and may 746 // therefore be used safely when the heap is unparseable. 747 HeapWord* block_start_careful(const void* p) const { 748 return _offsets.block_start_careful(p); 749 } 750 751 // Requires that "addr" is within the region. Returns the start of the 752 // first ("careful") block that starts at or after "addr", or else the 753 // "end" of the region if there is no such block. 754 HeapWord* next_block_start_careful(HeapWord* addr); 755 756 size_t recorded_rs_length() const { return _recorded_rs_length; } 757 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 758 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 759 760 void set_recorded_rs_length(size_t rs_length) { 761 _recorded_rs_length = rs_length; 762 } 763 764 void set_predicted_elapsed_time_ms(double ms) { 765 _predicted_elapsed_time_ms = ms; 766 } 767 768 void set_predicted_bytes_to_copy(size_t bytes) { 769 _predicted_bytes_to_copy = bytes; 770 } 771 772 virtual CompactibleSpace* next_compaction_space() const; 773 774 virtual void reset_after_compaction(); 775 776 // Routines for managing a list of code roots (attached to the 777 // this region's RSet) that point into this heap region. 778 void add_strong_code_root(nmethod* nm); 779 void remove_strong_code_root(nmethod* nm); 780 781 // During a collection, migrate the successfully evacuated 782 // strong code roots that referenced into this region to the 783 // new regions that they now point into. Unsuccessfully 784 // evacuated code roots are not migrated. 785 void migrate_strong_code_roots(); 786 787 // Applies blk->do_code_blob() to each of the entries in 788 // the strong code roots list for this region 789 void strong_code_roots_do(CodeBlobClosure* blk) const; 790 791 // Verify that the entries on the strong code root list for this 792 // region are live and include at least one pointer into this region. 793 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 794 795 void print() const; 796 void print_on(outputStream* st) const; 797 798 // vo == UsePrevMarking -> use "prev" marking information, 799 // vo == UseNextMarking -> use "next" marking information 800 // vo == UseMarkWord -> use the mark word in the object header 801 // 802 // NOTE: Only the "prev" marking information is guaranteed to be 803 // consistent most of the time, so most calls to this should use 804 // vo == UsePrevMarking. 805 // Currently, there is only one case where this is called with 806 // vo == UseNextMarking, which is to verify the "next" marking 807 // information at the end of remark. 808 // Currently there is only one place where this is called with 809 // vo == UseMarkWord, which is to verify the marking during a 810 // full GC. 811 void verify(VerifyOption vo, bool *failures) const; 812 813 // Override; it uses the "prev" marking information 814 virtual void verify() const; 815 }; 816 817 // HeapRegionClosure is used for iterating over regions. 818 // Terminates the iteration when the "doHeapRegion" method returns "true". 819 class HeapRegionClosure : public StackObj { 820 friend class HeapRegionSeq; 821 friend class G1CollectedHeap; 822 823 bool _complete; 824 void incomplete() { _complete = false; } 825 826 public: 827 HeapRegionClosure(): _complete(true) {} 828 829 // Typically called on each region until it returns true. 830 virtual bool doHeapRegion(HeapRegion* r) = 0; 831 832 // True after iteration if the closure was applied to all heap regions 833 // and returned "false" in all cases. 834 bool complete() { return _complete; } 835 }; 836 837 #endif // INCLUDE_ALL_GCS 838 839 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP