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.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 HeapRegionRemSet; 50 class HeapRegionRemSetIterator; 51 class HeapRegion; 52 class HeapRegionSetBase; 53 class nmethod; 54 55 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]" 56 #define HR_FORMAT_PARAMS(_hr_) \ 57 (_hr_)->hrs_index(), \ 58 (_hr_)->is_survivor() ? "S" : (_hr_)->is_young() ? "E" : \ 59 (_hr_)->startsHumongous() ? "HS" : \ 60 (_hr_)->continuesHumongous() ? "HC" : \ 61 !(_hr_)->is_empty() ? "O" : "F", \ 62 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 63 64 // sentinel value for hrs_index 65 #define G1_NO_HRS_INDEX ((uint) -1) 66 67 // A dirty card to oop closure for heap regions. It 68 // knows how to get the G1 heap and how to use the bitmap 69 // in the concurrent marker used by G1 to filter remembered 70 // sets. 71 72 class HeapRegionDCTOC : public DirtyCardToOopClosure { 73 public: 74 // Specification of possible DirtyCardToOopClosure filtering. 75 enum FilterKind { 76 NoFilterKind, 77 IntoCSFilterKind, 78 OutOfRegionFilterKind 79 }; 80 81 protected: 82 HeapRegion* _hr; 83 FilterKind _fk; 84 G1CollectedHeap* _g1; 85 86 // Walk the given memory region from bottom to (actual) top 87 // looking for objects and applying the oop closure (_cl) to 88 // them. The base implementation of this treats the area as 89 // blocks, where a block may or may not be an object. Sub- 90 // classes should override this to provide more accurate 91 // or possibly more efficient walking. 92 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); 93 94 public: 95 HeapRegionDCTOC(G1CollectedHeap* g1, 96 HeapRegion* hr, ExtendedOopClosure* cl, 97 CardTableModRefBS::PrecisionStyle precision, 98 FilterKind fk); 99 }; 100 101 // The complicating factor is that BlockOffsetTable diverged 102 // significantly, and we need functionality that is only in the G1 version. 103 // So I copied that code, which led to an alternate G1 version of 104 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 105 // be reconciled, then G1OffsetTableContigSpace could go away. 106 107 // The idea behind time stamps is the following. Doing a save_marks on 108 // all regions at every GC pause is time consuming (if I remember 109 // well, 10ms or so). So, we would like to do that only for regions 110 // that are GC alloc regions. To achieve this, we use time 111 // stamps. For every evacuation pause, G1CollectedHeap generates a 112 // unique time stamp (essentially a counter that gets 113 // incremented). Every time we want to call save_marks on a region, 114 // we set the saved_mark_word to top and also copy the current GC 115 // time stamp to the time stamp field of the space. Reading the 116 // saved_mark_word involves checking the time stamp of the 117 // region. If it is the same as the current GC time stamp, then we 118 // can safely read the saved_mark_word field, as it is valid. If the 119 // time stamp of the region is not the same as the current GC time 120 // stamp, then we instead read top, as the saved_mark_word field is 121 // invalid. Time stamps (on the regions and also on the 122 // G1CollectedHeap) are reset at every cleanup (we iterate over 123 // the regions anyway) and at the end of a Full GC. The current scheme 124 // that uses sequential unsigned ints will fail only if we have 4b 125 // evacuation pauses between two cleanups, which is _highly_ unlikely. 126 class G1OffsetTableContigSpace: public CompactibleSpace { 127 friend class VMStructs; 128 HeapWord* _top; 129 protected: 130 G1BlockOffsetArrayContigSpace _offsets; 131 Mutex _par_alloc_lock; 132 volatile unsigned _gc_time_stamp; 133 // When we need to retire an allocation region, while other threads 134 // are also concurrently trying to allocate into it, we typically 135 // allocate a dummy object at the end of the region to ensure that 136 // no more allocations can take place in it. However, sometimes we 137 // want to know where the end of the last "real" object we allocated 138 // into the region was and this is what this keeps track. 139 HeapWord* _pre_dummy_top; 140 141 public: 142 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 143 MemRegion mr); 144 145 void set_top(HeapWord* value) { _top = value; } 146 HeapWord* top() const { return _top; } 147 148 protected: 149 // Reset the G1OffsetTableContigSpace. 150 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 151 152 HeapWord** top_addr() { return &_top; } 153 // Allocation helpers (return NULL if full). 154 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); 155 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); 156 157 public: 158 void reset_after_compaction() { set_top(compaction_top()); } 159 160 size_t used() const { return byte_size(bottom(), top()); } 161 size_t free() const { return byte_size(top(), end()); } 162 bool is_free_block(const HeapWord* p) const { return p >= top(); } 163 164 MemRegion used_region() const { return MemRegion(bottom(), top()); } 165 166 void object_iterate(ObjectClosure* blk); 167 void safe_object_iterate(ObjectClosure* blk); 168 169 void set_bottom(HeapWord* value); 170 void set_end(HeapWord* value); 171 172 virtual HeapWord* saved_mark_word() const; 173 void record_top_and_timestamp(); 174 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 175 unsigned get_gc_time_stamp() { return _gc_time_stamp; } 176 177 // See the comment above in the declaration of _pre_dummy_top for an 178 // explanation of what it is. 179 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 180 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 181 _pre_dummy_top = pre_dummy_top; 182 } 183 HeapWord* pre_dummy_top() { 184 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 185 } 186 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 187 188 virtual void clear(bool mangle_space); 189 190 HeapWord* block_start(const void* p); 191 HeapWord* block_start_const(const void* p) const; 192 193 void prepare_for_compaction(CompactPoint* cp); 194 195 // Add offset table update. 196 virtual HeapWord* allocate(size_t word_size); 197 HeapWord* par_allocate(size_t word_size); 198 199 // MarkSweep support phase3 200 virtual HeapWord* initialize_threshold(); 201 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 202 203 virtual void print() const; 204 205 void reset_bot() { 206 _offsets.reset_bot(); 207 } 208 209 void update_bot_for_object(HeapWord* start, size_t word_size) { 210 _offsets.alloc_block(start, word_size); 211 } 212 213 void print_bot_on(outputStream* out) { 214 _offsets.print_on(out); 215 } 216 }; 217 218 class HeapRegion: public G1OffsetTableContigSpace { 219 friend class VMStructs; 220 private: 221 222 enum HumongousType { 223 NotHumongous = 0, 224 StartsHumongous, 225 ContinuesHumongous 226 }; 227 228 // The remembered set for this region. 229 // (Might want to make this "inline" later, to avoid some alloc failure 230 // issues.) 231 HeapRegionRemSet* _rem_set; 232 233 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 234 235 protected: 236 // The index of this region in the heap region sequence. 237 uint _hrs_index; 238 239 HumongousType _humongous_type; 240 // For a humongous region, region in which it starts. 241 HeapRegion* _humongous_start_region; 242 // For the start region of a humongous sequence, it's original end(). 243 HeapWord* _orig_end; 244 245 // True iff the region is in current collection_set. 246 bool _in_collection_set; 247 248 // True iff an attempt to evacuate an object in the region failed. 249 bool _evacuation_failed; 250 251 // A heap region may be a member one of a number of special subsets, each 252 // represented as linked lists through the field below. Currently, there 253 // is only one set: 254 // The collection set. 255 HeapRegion* _next_in_special_set; 256 257 // next region in the young "generation" region set 258 HeapRegion* _next_young_region; 259 260 // Next region whose cards need cleaning 261 HeapRegion* _next_dirty_cards_region; 262 263 // Fields used by the HeapRegionSetBase class and subclasses. 264 HeapRegion* _next; 265 HeapRegion* _prev; 266 #ifdef ASSERT 267 HeapRegionSetBase* _containing_set; 268 #endif // ASSERT 269 270 // For parallel heapRegion traversal. 271 jint _claimed; 272 273 // We use concurrent marking to determine the amount of live data 274 // in each heap region. 275 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 276 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 277 278 // The calculated GC efficiency of the region. 279 double _gc_efficiency; 280 281 enum YoungType { 282 NotYoung, // a region is not young 283 Young, // a region is young 284 Survivor // a region is young and it contains survivors 285 }; 286 287 volatile YoungType _young_type; 288 int _young_index_in_cset; 289 SurvRateGroup* _surv_rate_group; 290 int _age_index; 291 292 // The start of the unmarked area. The unmarked area extends from this 293 // word until the top and/or end of the region, and is the part 294 // of the region for which no marking was done, i.e. objects may 295 // have been allocated in this part since the last mark phase. 296 // "prev" is the top at the start of the last completed marking. 297 // "next" is the top at the start of the in-progress marking (if any.) 298 HeapWord* _prev_top_at_mark_start; 299 HeapWord* _next_top_at_mark_start; 300 // If a collection pause is in progress, this is the top at the start 301 // of that pause. 302 303 void init_top_at_mark_start() { 304 assert(_prev_marked_bytes == 0 && 305 _next_marked_bytes == 0, 306 "Must be called after zero_marked_bytes."); 307 HeapWord* bot = bottom(); 308 _prev_top_at_mark_start = bot; 309 _next_top_at_mark_start = bot; 310 } 311 312 void set_young_type(YoungType new_type) { 313 //assert(_young_type != new_type, "setting the same type" ); 314 // TODO: add more assertions here 315 _young_type = new_type; 316 } 317 318 // Cached attributes used in the collection set policy information 319 320 // The RSet length that was added to the total value 321 // for the collection set. 322 size_t _recorded_rs_length; 323 324 // The predicted elapsed time that was added to total value 325 // for the collection set. 326 double _predicted_elapsed_time_ms; 327 328 // The predicted number of bytes to copy that was added to 329 // the total value for the collection set. 330 size_t _predicted_bytes_to_copy; 331 332 public: 333 HeapRegion(uint hrs_index, 334 G1BlockOffsetSharedArray* sharedOffsetArray, 335 MemRegion mr); 336 337 // Initializing the HeapRegion not only resets the data structure, but also 338 // resets the BOT for that heap region. 339 // The default values for clear_space means that we will do the clearing if 340 // there's clearing to be done ourselves. We also always mangle the space. 341 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 342 343 static int LogOfHRGrainBytes; 344 static int LogOfHRGrainWords; 345 346 static size_t GrainBytes; 347 static size_t GrainWords; 348 static size_t CardsPerRegion; 349 350 static size_t align_up_to_region_byte_size(size_t sz) { 351 return (sz + (size_t) GrainBytes - 1) & 352 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 353 } 354 355 static size_t max_region_size(); 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(size_t initial_heap_size, size_t max_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 ParMarkRootClaimValue = 9 376 }; 377 378 // All allocated blocks are occupied by objects in a HeapRegion 379 bool block_is_obj(const HeapWord* p) const; 380 381 // Returns the object size for all valid block starts 382 // and the amount of unallocated words if called on top() 383 size_t block_size(const HeapWord* p) const; 384 385 inline HeapWord* par_allocate_no_bot_updates(size_t word_size); 386 inline HeapWord* allocate_no_bot_updates(size_t word_size); 387 388 // If this region is a member of a HeapRegionSeq, the index in that 389 // sequence, otherwise -1. 390 uint hrs_index() const { return _hrs_index; } 391 392 // The number of bytes marked live in the region in the last marking phase. 393 size_t marked_bytes() { return _prev_marked_bytes; } 394 size_t live_bytes() { 395 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 396 } 397 398 // The number of bytes counted in the next marking. 399 size_t next_marked_bytes() { return _next_marked_bytes; } 400 // The number of bytes live wrt the next marking. 401 size_t next_live_bytes() { 402 return 403 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 404 } 405 406 // A lower bound on the amount of garbage bytes in the region. 407 size_t garbage_bytes() { 408 size_t used_at_mark_start_bytes = 409 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 410 assert(used_at_mark_start_bytes >= marked_bytes(), 411 "Can't mark more than we have."); 412 return used_at_mark_start_bytes - marked_bytes(); 413 } 414 415 // Return the amount of bytes we'll reclaim if we collect this 416 // region. This includes not only the known garbage bytes in the 417 // region but also any unallocated space in it, i.e., [top, end), 418 // since it will also be reclaimed if we collect the region. 419 size_t reclaimable_bytes() { 420 size_t known_live_bytes = live_bytes(); 421 assert(known_live_bytes <= capacity(), "sanity"); 422 return capacity() - known_live_bytes; 423 } 424 425 // An upper bound on the number of live bytes in the region. 426 size_t max_live_bytes() { return used() - garbage_bytes(); } 427 428 void add_to_marked_bytes(size_t incr_bytes) { 429 _next_marked_bytes = _next_marked_bytes + incr_bytes; 430 assert(_next_marked_bytes <= used(), "invariant" ); 431 } 432 433 void zero_marked_bytes() { 434 _prev_marked_bytes = _next_marked_bytes = 0; 435 } 436 437 bool isHumongous() const { return _humongous_type != NotHumongous; } 438 bool startsHumongous() const { return _humongous_type == StartsHumongous; } 439 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; } 440 // For a humongous region, region in which it starts. 441 HeapRegion* humongous_start_region() const { 442 return _humongous_start_region; 443 } 444 445 // Return the number of distinct regions that are covered by this region: 446 // 1 if the region is not humongous, >= 1 if the region is humongous. 447 uint region_num() const { 448 if (!isHumongous()) { 449 return 1U; 450 } else { 451 assert(startsHumongous(), "doesn't make sense on HC regions"); 452 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity"); 453 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes); 454 } 455 } 456 457 // Return the index + 1 of the last HC regions that's associated 458 // with this HS region. 459 uint last_hc_index() const { 460 assert(startsHumongous(), "don't call this otherwise"); 461 return hrs_index() + region_num(); 462 } 463 464 // Same as Space::is_in_reserved, but will use the original size of the region. 465 // The original size is different only for start humongous regions. They get 466 // their _end set up to be the end of the last continues region of the 467 // corresponding humongous object. 468 bool is_in_reserved_raw(const void* p) const { 469 return _bottom <= p && p < _orig_end; 470 } 471 472 // Makes the current region be a "starts humongous" region, i.e., 473 // the first region in a series of one or more contiguous regions 474 // that will contain a single "humongous" object. The two parameters 475 // are as follows: 476 // 477 // new_top : The new value of the top field of this region which 478 // points to the end of the humongous object that's being 479 // allocated. If there is more than one region in the series, top 480 // will lie beyond this region's original end field and on the last 481 // region in the series. 482 // 483 // new_end : The new value of the end field of this region which 484 // points to the end of the last region in the series. If there is 485 // one region in the series (namely: this one) end will be the same 486 // as the original end of this region. 487 // 488 // Updating top and end as described above makes this region look as 489 // if it spans the entire space taken up by all the regions in the 490 // series and an single allocation moved its top to new_top. This 491 // ensures that the space (capacity / allocated) taken up by all 492 // humongous regions can be calculated by just looking at the 493 // "starts humongous" regions and by ignoring the "continues 494 // humongous" regions. 495 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); 496 497 // Makes the current region be a "continues humongous' 498 // region. first_hr is the "start humongous" region of the series 499 // which this region will be part of. 500 void set_continuesHumongous(HeapRegion* first_hr); 501 502 // Unsets the humongous-related fields on the region. 503 void set_notHumongous(); 504 505 // If the region has a remembered set, return a pointer to it. 506 HeapRegionRemSet* rem_set() const { 507 return _rem_set; 508 } 509 510 // True iff the region is in current collection_set. 511 bool in_collection_set() const { 512 return _in_collection_set; 513 } 514 void set_in_collection_set(bool b) { 515 _in_collection_set = b; 516 } 517 HeapRegion* next_in_collection_set() { 518 assert(in_collection_set(), "should only invoke on member of CS."); 519 assert(_next_in_special_set == NULL || 520 _next_in_special_set->in_collection_set(), 521 "Malformed CS."); 522 return _next_in_special_set; 523 } 524 void set_next_in_collection_set(HeapRegion* r) { 525 assert(in_collection_set(), "should only invoke on member of CS."); 526 assert(r == NULL || r->in_collection_set(), "Malformed CS."); 527 _next_in_special_set = r; 528 } 529 530 // Methods used by the HeapRegionSetBase class and subclasses. 531 532 // Getter and setter for the next and prev fields used to link regions into 533 // linked lists. 534 HeapRegion* next() { return _next; } 535 HeapRegion* prev() { return _prev; } 536 537 void set_next(HeapRegion* next) { _next = next; } 538 void set_prev(HeapRegion* prev) { _prev = prev; } 539 540 // Every region added to a set is tagged with a reference to that 541 // set. This is used for doing consistency checking to make sure that 542 // the contents of a set are as they should be and it's only 543 // available in non-product builds. 544 #ifdef ASSERT 545 void set_containing_set(HeapRegionSetBase* containing_set) { 546 assert((containing_set == NULL && _containing_set != NULL) || 547 (containing_set != NULL && _containing_set == NULL), 548 err_msg("containing_set: "PTR_FORMAT" " 549 "_containing_set: "PTR_FORMAT, 550 p2i(containing_set), p2i(_containing_set))); 551 552 _containing_set = containing_set; 553 } 554 555 HeapRegionSetBase* containing_set() { return _containing_set; } 556 #else // ASSERT 557 void set_containing_set(HeapRegionSetBase* containing_set) { } 558 559 // containing_set() is only used in asserts so there's no reason 560 // to provide a dummy version of it. 561 #endif // ASSERT 562 563 HeapRegion* get_next_young_region() { return _next_young_region; } 564 void set_next_young_region(HeapRegion* hr) { 565 _next_young_region = hr; 566 } 567 568 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 569 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 570 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 571 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 572 573 HeapWord* orig_end() { return _orig_end; } 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 // Note the start or end of marking. This tells the heap region 584 // that the collector is about to start or has finished (concurrently) 585 // marking the heap. 586 587 // Notify the region that concurrent marking is starting. Initialize 588 // all fields related to the next marking info. 589 inline void note_start_of_marking(); 590 591 // Notify the region that concurrent marking has finished. Copy the 592 // (now finalized) next marking info fields into the prev marking 593 // info fields. 594 inline void note_end_of_marking(); 595 596 // Notify the region that it will be used as to-space during a GC 597 // and we are about to start copying objects into it. 598 inline void note_start_of_copying(bool during_initial_mark); 599 600 // Notify the region that it ceases being to-space during a GC and 601 // we will not copy objects into it any more. 602 inline void note_end_of_copying(bool during_initial_mark); 603 604 // Notify the region that we are about to start processing 605 // self-forwarded objects during evac failure handling. 606 void note_self_forwarding_removal_start(bool during_initial_mark, 607 bool during_conc_mark); 608 609 // Notify the region that we have finished processing self-forwarded 610 // objects during evac failure handling. 611 void note_self_forwarding_removal_end(bool during_initial_mark, 612 bool during_conc_mark, 613 size_t marked_bytes); 614 615 // Returns "false" iff no object in the region was allocated when the 616 // last mark phase ended. 617 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 618 619 void reset_during_compaction() { 620 assert(isHumongous() && startsHumongous(), 621 "should only be called for starts humongous regions"); 622 623 zero_marked_bytes(); 624 init_top_at_mark_start(); 625 } 626 627 void calc_gc_efficiency(void); 628 double gc_efficiency() { return _gc_efficiency;} 629 630 bool is_young() const { return _young_type != NotYoung; } 631 bool is_survivor() const { return _young_type == Survivor; } 632 633 int young_index_in_cset() const { return _young_index_in_cset; } 634 void set_young_index_in_cset(int index) { 635 assert( (index == -1) || is_young(), "pre-condition" ); 636 _young_index_in_cset = index; 637 } 638 639 int age_in_surv_rate_group() { 640 assert( _surv_rate_group != NULL, "pre-condition" ); 641 assert( _age_index > -1, "pre-condition" ); 642 return _surv_rate_group->age_in_group(_age_index); 643 } 644 645 void record_surv_words_in_group(size_t words_survived) { 646 assert( _surv_rate_group != NULL, "pre-condition" ); 647 assert( _age_index > -1, "pre-condition" ); 648 int age_in_group = age_in_surv_rate_group(); 649 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 650 } 651 652 int age_in_surv_rate_group_cond() { 653 if (_surv_rate_group != NULL) 654 return age_in_surv_rate_group(); 655 else 656 return -1; 657 } 658 659 SurvRateGroup* surv_rate_group() { 660 return _surv_rate_group; 661 } 662 663 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 664 assert( surv_rate_group != NULL, "pre-condition" ); 665 assert( _surv_rate_group == NULL, "pre-condition" ); 666 assert( is_young(), "pre-condition" ); 667 668 _surv_rate_group = surv_rate_group; 669 _age_index = surv_rate_group->next_age_index(); 670 } 671 672 void uninstall_surv_rate_group() { 673 if (_surv_rate_group != NULL) { 674 assert( _age_index > -1, "pre-condition" ); 675 assert( is_young(), "pre-condition" ); 676 677 _surv_rate_group = NULL; 678 _age_index = -1; 679 } else { 680 assert( _age_index == -1, "pre-condition" ); 681 } 682 } 683 684 void set_young() { set_young_type(Young); } 685 686 void set_survivor() { set_young_type(Survivor); } 687 688 void set_not_young() { set_young_type(NotYoung); } 689 690 // Determine if an object has been allocated since the last 691 // mark performed by the collector. This returns true iff the object 692 // is within the unmarked area of the region. 693 bool obj_allocated_since_prev_marking(oop obj) const { 694 return (HeapWord *) obj >= prev_top_at_mark_start(); 695 } 696 bool obj_allocated_since_next_marking(oop obj) const { 697 return (HeapWord *) obj >= next_top_at_mark_start(); 698 } 699 700 // For parallel heapRegion traversal. 701 bool claimHeapRegion(int claimValue); 702 jint claim_value() { return _claimed; } 703 // Use this carefully: only when you're sure no one is claiming... 704 void set_claim_value(int claimValue) { _claimed = claimValue; } 705 706 // Returns the "evacuation_failed" property of the region. 707 bool evacuation_failed() { return _evacuation_failed; } 708 709 // Sets the "evacuation_failed" property of the region. 710 void set_evacuation_failed(bool b) { 711 _evacuation_failed = b; 712 713 if (b) { 714 _next_marked_bytes = 0; 715 } 716 } 717 718 // Requires that "mr" be entirely within the region. 719 // Apply "cl->do_object" to all objects that intersect with "mr". 720 // If the iteration encounters an unparseable portion of the region, 721 // or if "cl->abort()" is true after a closure application, 722 // terminate the iteration and return the address of the start of the 723 // subregion that isn't done. (The two can be distinguished by querying 724 // "cl->abort()".) Return of "NULL" indicates that the iteration 725 // completed. 726 HeapWord* 727 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 728 729 // filter_young: if true and the region is a young region then we 730 // skip the iteration. 731 // card_ptr: if not NULL, and we decide that the card is not young 732 // and we iterate over it, we'll clean the card before we start the 733 // iteration. 734 HeapWord* 735 oops_on_card_seq_iterate_careful(MemRegion mr, 736 FilterOutOfRegionClosure* cl, 737 bool filter_young, 738 jbyte* card_ptr); 739 740 // A version of block start that is guaranteed to find *some* block 741 // boundary at or before "p", but does not object iteration, and may 742 // therefore be used safely when the heap is unparseable. 743 HeapWord* block_start_careful(const void* p) const { 744 return _offsets.block_start_careful(p); 745 } 746 747 // Requires that "addr" is within the region. Returns the start of the 748 // first ("careful") block that starts at or after "addr", or else the 749 // "end" of the region if there is no such block. 750 HeapWord* next_block_start_careful(HeapWord* addr); 751 752 size_t recorded_rs_length() const { return _recorded_rs_length; } 753 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 754 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 755 756 void set_recorded_rs_length(size_t rs_length) { 757 _recorded_rs_length = rs_length; 758 } 759 760 void set_predicted_elapsed_time_ms(double ms) { 761 _predicted_elapsed_time_ms = ms; 762 } 763 764 void set_predicted_bytes_to_copy(size_t bytes) { 765 _predicted_bytes_to_copy = bytes; 766 } 767 768 virtual CompactibleSpace* next_compaction_space() const; 769 770 virtual void reset_after_compaction(); 771 772 // Routines for managing a list of code roots (attached to the 773 // this region's RSet) that point into this heap region. 774 void add_strong_code_root(nmethod* nm); 775 void remove_strong_code_root(nmethod* nm); 776 777 // During a collection, migrate the successfully evacuated 778 // strong code roots that referenced into this region to the 779 // new regions that they now point into. Unsuccessfully 780 // evacuated code roots are not migrated. 781 void migrate_strong_code_roots(); 782 783 // Applies blk->do_code_blob() to each of the entries in 784 // the strong code roots list for this region 785 void strong_code_roots_do(CodeBlobClosure* blk) const; 786 787 // Verify that the entries on the strong code root list for this 788 // region are live and include at least one pointer into this region. 789 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 790 791 void print() const; 792 void print_on(outputStream* st) const; 793 794 // vo == UsePrevMarking -> use "prev" marking information, 795 // vo == UseNextMarking -> use "next" marking information 796 // vo == UseMarkWord -> use the mark word in the object header 797 // 798 // NOTE: Only the "prev" marking information is guaranteed to be 799 // consistent most of the time, so most calls to this should use 800 // vo == UsePrevMarking. 801 // Currently, there is only one case where this is called with 802 // vo == UseNextMarking, which is to verify the "next" marking 803 // information at the end of remark. 804 // Currently there is only one place where this is called with 805 // vo == UseMarkWord, which is to verify the marking during a 806 // full GC. 807 void verify(VerifyOption vo, bool *failures) const; 808 809 // Override; it uses the "prev" marking information 810 virtual void verify() const; 811 }; 812 813 // HeapRegionClosure is used for iterating over regions. 814 // Terminates the iteration when the "doHeapRegion" method returns "true". 815 class HeapRegionClosure : public StackObj { 816 friend class HeapRegionSeq; 817 friend class G1CollectedHeap; 818 819 bool _complete; 820 void incomplete() { _complete = false; } 821 822 public: 823 HeapRegionClosure(): _complete(true) {} 824 825 // Typically called on each region until it returns true. 826 virtual bool doHeapRegion(HeapRegion* r) = 0; 827 828 // True after iteration if the closure was applied to all heap regions 829 // and returned "false" in all cases. 830 bool complete() { return _complete; } 831 }; 832 833 #endif // INCLUDE_ALL_GCS 834 835 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP