1 /* 2 * Copyright (c) 2001, 2011, 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 36 #ifndef SERIALGC 37 38 // A HeapRegion is the smallest piece of a G1CollectedHeap that 39 // can be collected independently. 40 41 // NOTE: Although a HeapRegion is a Space, its 42 // Space::initDirtyCardClosure method must not be called. 43 // The problem is that the existence of this method breaks 44 // the independence of barrier sets from remembered sets. 45 // The solution is to remove this method from the definition 46 // of a Space. 47 48 class CompactibleSpace; 49 class ContiguousSpace; 50 class HeapRegionRemSet; 51 class HeapRegionRemSetIterator; 52 class HeapRegion; 53 class HeapRegionSetBase; 54 55 #define HR_FORMAT SIZE_FORMAT":(%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_)->bottom(), (_hr_)->top(), (_hr_)->end() 60 61 // A dirty card to oop closure for heap regions. It 62 // knows how to get the G1 heap and how to use the bitmap 63 // in the concurrent marker used by G1 to filter remembered 64 // sets. 65 66 class HeapRegionDCTOC : public ContiguousSpaceDCTOC { 67 public: 68 // Specification of possible DirtyCardToOopClosure filtering. 69 enum FilterKind { 70 NoFilterKind, 71 IntoCSFilterKind, 72 OutOfRegionFilterKind 73 }; 74 75 protected: 76 HeapRegion* _hr; 77 FilterKind _fk; 78 G1CollectedHeap* _g1; 79 80 void walk_mem_region_with_cl(MemRegion mr, 81 HeapWord* bottom, HeapWord* top, 82 OopClosure* cl); 83 84 // We don't specialize this for FilteringClosure; filtering is handled by 85 // the "FilterKind" mechanism. But we provide this to avoid a compiler 86 // warning. 87 void walk_mem_region_with_cl(MemRegion mr, 88 HeapWord* bottom, HeapWord* top, 89 FilteringClosure* cl) { 90 HeapRegionDCTOC::walk_mem_region_with_cl(mr, bottom, top, 91 (OopClosure*)cl); 92 } 93 94 // Get the actual top of the area on which the closure will 95 // operate, given where the top is assumed to be (the end of the 96 // memory region passed to do_MemRegion) and where the object 97 // at the top is assumed to start. For example, an object may 98 // start at the top but actually extend past the assumed top, 99 // in which case the top becomes the end of the object. 100 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj) { 101 return ContiguousSpaceDCTOC::get_actual_top(top, top_obj); 102 } 103 104 // Walk the given memory region from bottom to (actual) top 105 // looking for objects and applying the oop closure (_cl) to 106 // them. The base implementation of this treats the area as 107 // blocks, where a block may or may not be an object. Sub- 108 // classes should override this to provide more accurate 109 // or possibly more efficient walking. 110 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top) { 111 Filtering_DCTOC::walk_mem_region(mr, bottom, top); 112 } 113 114 public: 115 HeapRegionDCTOC(G1CollectedHeap* g1, 116 HeapRegion* hr, OopClosure* cl, 117 CardTableModRefBS::PrecisionStyle precision, 118 FilterKind fk); 119 }; 120 121 // The complicating factor is that BlockOffsetTable diverged 122 // significantly, and we need functionality that is only in the G1 version. 123 // So I copied that code, which led to an alternate G1 version of 124 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 125 // be reconciled, then G1OffsetTableContigSpace could go away. 126 127 // The idea behind time stamps is the following. Doing a save_marks on 128 // all regions at every GC pause is time consuming (if I remember 129 // well, 10ms or so). So, we would like to do that only for regions 130 // that are GC alloc regions. To achieve this, we use time 131 // stamps. For every evacuation pause, G1CollectedHeap generates a 132 // unique time stamp (essentially a counter that gets 133 // incremented). Every time we want to call save_marks on a region, 134 // we set the saved_mark_word to top and also copy the current GC 135 // time stamp to the time stamp field of the space. Reading the 136 // saved_mark_word involves checking the time stamp of the 137 // region. If it is the same as the current GC time stamp, then we 138 // can safely read the saved_mark_word field, as it is valid. If the 139 // time stamp of the region is not the same as the current GC time 140 // stamp, then we instead read top, as the saved_mark_word field is 141 // invalid. Time stamps (on the regions and also on the 142 // G1CollectedHeap) are reset at every cleanup (we iterate over 143 // the regions anyway) and at the end of a Full GC. The current scheme 144 // that uses sequential unsigned ints will fail only if we have 4b 145 // evacuation pauses between two cleanups, which is _highly_ unlikely. 146 147 class G1OffsetTableContigSpace: public ContiguousSpace { 148 friend class VMStructs; 149 protected: 150 G1BlockOffsetArrayContigSpace _offsets; 151 Mutex _par_alloc_lock; 152 volatile unsigned _gc_time_stamp; 153 // When we need to retire an allocation region, while other threads 154 // are also concurrently trying to allocate into it, we typically 155 // allocate a dummy object at the end of the region to ensure that 156 // no more allocations can take place in it. However, sometimes we 157 // want to know where the end of the last "real" object we allocated 158 // into the region was and this is what this keeps track. 159 HeapWord* _pre_dummy_top; 160 161 public: 162 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be 163 // assumed to contain zeros. 164 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 165 MemRegion mr, bool is_zeroed = false); 166 167 void set_bottom(HeapWord* value); 168 void set_end(HeapWord* value); 169 170 virtual HeapWord* saved_mark_word() const; 171 virtual void set_saved_mark(); 172 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 173 174 // See the comment above in the declaration of _pre_dummy_top for an 175 // explanation of what it is. 176 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 177 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 178 _pre_dummy_top = pre_dummy_top; 179 } 180 HeapWord* pre_dummy_top() { 181 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 182 } 183 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 184 185 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 186 virtual void clear(bool mangle_space); 187 188 HeapWord* block_start(const void* p); 189 HeapWord* block_start_const(const void* p) const; 190 191 // Add offset table update. 192 virtual HeapWord* allocate(size_t word_size); 193 HeapWord* par_allocate(size_t word_size); 194 195 // MarkSweep support phase3 196 virtual HeapWord* initialize_threshold(); 197 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 198 199 virtual void print() const; 200 201 void reset_bot() { 202 _offsets.zero_bottom_entry(); 203 _offsets.initialize_threshold(); 204 } 205 206 void update_bot_for_object(HeapWord* start, size_t word_size) { 207 _offsets.alloc_block(start, word_size); 208 } 209 210 void print_bot_on(outputStream* out) { 211 _offsets.print_on(out); 212 } 213 }; 214 215 class HeapRegion: public G1OffsetTableContigSpace { 216 friend class VMStructs; 217 private: 218 219 enum HumongousType { 220 NotHumongous = 0, 221 StartsHumongous, 222 ContinuesHumongous 223 }; 224 225 // Requires that the region "mr" be dense with objects, and begin and end 226 // with an object. 227 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl); 228 229 // The remembered set for this region. 230 // (Might want to make this "inline" later, to avoid some alloc failure 231 // issues.) 232 HeapRegionRemSet* _rem_set; 233 234 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 235 236 protected: 237 // The index of this region in the heap region sequence. 238 size_t _hrs_index; 239 240 HumongousType _humongous_type; 241 // For a humongous region, region in which it starts. 242 HeapRegion* _humongous_start_region; 243 // For the start region of a humongous sequence, it's original end(). 244 HeapWord* _orig_end; 245 246 // True iff the region is in current collection_set. 247 bool _in_collection_set; 248 249 // True iff an attempt to evacuate an object in the region failed. 250 bool _evacuation_failed; 251 252 // A heap region may be a member one of a number of special subsets, each 253 // represented as linked lists through the field below. Currently, these 254 // sets include: 255 // The collection set. 256 // The set of allocation regions used in a collection pause. 257 // Spaces that may contain gray objects. 258 HeapRegion* _next_in_special_set; 259 260 // next region in the young "generation" region set 261 HeapRegion* _next_young_region; 262 263 // Next region whose cards need cleaning 264 HeapRegion* _next_dirty_cards_region; 265 266 // Fields used by the HeapRegionSetBase class and subclasses. 267 HeapRegion* _next; 268 #ifdef ASSERT 269 HeapRegionSetBase* _containing_set; 270 #endif // ASSERT 271 bool _pending_removal; 272 273 // For parallel heapRegion traversal. 274 jint _claimed; 275 276 // We use concurrent marking to determine the amount of live data 277 // in each heap region. 278 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 279 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 280 281 // See "sort_index" method. -1 means is not in the array. 282 int _sort_index; 283 284 // <PREDICTION> 285 double _gc_efficiency; 286 // </PREDICTION> 287 288 enum YoungType { 289 NotYoung, // a region is not young 290 Young, // a region is young 291 Survivor // a region is young and it contains survivors 292 }; 293 294 volatile YoungType _young_type; 295 int _young_index_in_cset; 296 SurvRateGroup* _surv_rate_group; 297 int _age_index; 298 299 // The start of the unmarked area. The unmarked area extends from this 300 // word until the top and/or end of the region, and is the part 301 // of the region for which no marking was done, i.e. objects may 302 // have been allocated in this part since the last mark phase. 303 // "prev" is the top at the start of the last completed marking. 304 // "next" is the top at the start of the in-progress marking (if any.) 305 HeapWord* _prev_top_at_mark_start; 306 HeapWord* _next_top_at_mark_start; 307 // If a collection pause is in progress, this is the top at the start 308 // of that pause. 309 310 // We've counted the marked bytes of objects below here. 311 HeapWord* _top_at_conc_mark_count; 312 313 void init_top_at_mark_start() { 314 assert(_prev_marked_bytes == 0 && 315 _next_marked_bytes == 0, 316 "Must be called after zero_marked_bytes."); 317 HeapWord* bot = bottom(); 318 _prev_top_at_mark_start = bot; 319 _next_top_at_mark_start = bot; 320 _top_at_conc_mark_count = bot; 321 } 322 323 void set_young_type(YoungType new_type) { 324 //assert(_young_type != new_type, "setting the same type" ); 325 // TODO: add more assertions here 326 _young_type = new_type; 327 } 328 329 // Cached attributes used in the collection set policy information 330 331 // The RSet length that was added to the total value 332 // for the collection set. 333 size_t _recorded_rs_length; 334 335 // The predicted elapsed time that was added to total value 336 // for the collection set. 337 double _predicted_elapsed_time_ms; 338 339 // The predicted number of bytes to copy that was added to 340 // the total value for the collection set. 341 size_t _predicted_bytes_to_copy; 342 343 public: 344 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros. 345 HeapRegion(size_t hrs_index, 346 G1BlockOffsetSharedArray* sharedOffsetArray, 347 MemRegion mr, bool is_zeroed); 348 349 static int LogOfHRGrainBytes; 350 static int LogOfHRGrainWords; 351 352 static size_t GrainBytes; 353 static size_t GrainWords; 354 static size_t CardsPerRegion; 355 356 static size_t align_up_to_region_byte_size(size_t sz) { 357 return (sz + (size_t) GrainBytes - 1) & 358 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 359 } 360 361 // It sets up the heap region size (GrainBytes / GrainWords), as 362 // well as other related fields that are based on the heap region 363 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 364 // CardsPerRegion). All those fields are considered constant 365 // throughout the JVM's execution, therefore they should only be set 366 // up once during initialization time. 367 static void setup_heap_region_size(uintx min_heap_size); 368 369 enum ClaimValues { 370 InitialClaimValue = 0, 371 FinalCountClaimValue = 1, 372 NoteEndClaimValue = 2, 373 ScrubRemSetClaimValue = 3, 374 ParVerifyClaimValue = 4, 375 RebuildRSClaimValue = 5, 376 CompleteMarkCSetClaimValue = 6 377 }; 378 379 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) { 380 assert(is_young(), "we can only skip BOT updates on young regions"); 381 return ContiguousSpace::par_allocate(word_size); 382 } 383 inline HeapWord* allocate_no_bot_updates(size_t word_size) { 384 assert(is_young(), "we can only skip BOT updates on young regions"); 385 return ContiguousSpace::allocate(word_size); 386 } 387 388 // If this region is a member of a HeapRegionSeq, the index in that 389 // sequence, otherwise -1. 390 size_t 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 // An upper bound on the number of live bytes in the region. 416 size_t max_live_bytes() { return used() - garbage_bytes(); } 417 418 void add_to_marked_bytes(size_t incr_bytes) { 419 _next_marked_bytes = _next_marked_bytes + incr_bytes; 420 assert(_next_marked_bytes <= used(), "invariant" ); 421 } 422 423 void zero_marked_bytes() { 424 _prev_marked_bytes = _next_marked_bytes = 0; 425 } 426 427 bool isHumongous() const { return _humongous_type != NotHumongous; } 428 bool startsHumongous() const { return _humongous_type == StartsHumongous; } 429 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; } 430 // For a humongous region, region in which it starts. 431 HeapRegion* humongous_start_region() const { 432 return _humongous_start_region; 433 } 434 435 // Same as Space::is_in_reserved, but will use the original size of the region. 436 // The original size is different only for start humongous regions. They get 437 // their _end set up to be the end of the last continues region of the 438 // corresponding humongous object. 439 bool is_in_reserved_raw(const void* p) const { 440 return _bottom <= p && p < _orig_end; 441 } 442 443 // Makes the current region be a "starts humongous" region, i.e., 444 // the first region in a series of one or more contiguous regions 445 // that will contain a single "humongous" object. The two parameters 446 // are as follows: 447 // 448 // new_top : The new value of the top field of this region which 449 // points to the end of the humongous object that's being 450 // allocated. If there is more than one region in the series, top 451 // will lie beyond this region's original end field and on the last 452 // region in the series. 453 // 454 // new_end : The new value of the end field of this region which 455 // points to the end of the last region in the series. If there is 456 // one region in the series (namely: this one) end will be the same 457 // as the original end of this region. 458 // 459 // Updating top and end as described above makes this region look as 460 // if it spans the entire space taken up by all the regions in the 461 // series and an single allocation moved its top to new_top. This 462 // ensures that the space (capacity / allocated) taken up by all 463 // humongous regions can be calculated by just looking at the 464 // "starts humongous" regions and by ignoring the "continues 465 // humongous" regions. 466 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); 467 468 // Makes the current region be a "continues humongous' 469 // region. first_hr is the "start humongous" region of the series 470 // which this region will be part of. 471 void set_continuesHumongous(HeapRegion* first_hr); 472 473 // Unsets the humongous-related fields on the region. 474 void set_notHumongous(); 475 476 // If the region has a remembered set, return a pointer to it. 477 HeapRegionRemSet* rem_set() const { 478 return _rem_set; 479 } 480 481 // True iff the region is in current collection_set. 482 bool in_collection_set() const { 483 return _in_collection_set; 484 } 485 void set_in_collection_set(bool b) { 486 _in_collection_set = b; 487 } 488 HeapRegion* next_in_collection_set() { 489 assert(in_collection_set(), "should only invoke on member of CS."); 490 assert(_next_in_special_set == NULL || 491 _next_in_special_set->in_collection_set(), 492 "Malformed CS."); 493 return _next_in_special_set; 494 } 495 void set_next_in_collection_set(HeapRegion* r) { 496 assert(in_collection_set(), "should only invoke on member of CS."); 497 assert(r == NULL || r->in_collection_set(), "Malformed CS."); 498 _next_in_special_set = r; 499 } 500 501 // Methods used by the HeapRegionSetBase class and subclasses. 502 503 // Getter and setter for the next field used to link regions into 504 // linked lists. 505 HeapRegion* next() { return _next; } 506 507 void set_next(HeapRegion* next) { _next = next; } 508 509 // Every region added to a set is tagged with a reference to that 510 // set. This is used for doing consistency checking to make sure that 511 // the contents of a set are as they should be and it's only 512 // available in non-product builds. 513 #ifdef ASSERT 514 void set_containing_set(HeapRegionSetBase* containing_set) { 515 assert((containing_set == NULL && _containing_set != NULL) || 516 (containing_set != NULL && _containing_set == NULL), 517 err_msg("containing_set: "PTR_FORMAT" " 518 "_containing_set: "PTR_FORMAT, 519 containing_set, _containing_set)); 520 521 _containing_set = containing_set; 522 } 523 524 HeapRegionSetBase* containing_set() { return _containing_set; } 525 #else // ASSERT 526 void set_containing_set(HeapRegionSetBase* containing_set) { } 527 528 // containing_set() is only used in asserts so there's no reason 529 // to provide a dummy version of it. 530 #endif // ASSERT 531 532 // If we want to remove regions from a list in bulk we can simply tag 533 // them with the pending_removal tag and call the 534 // remove_all_pending() method on the list. 535 536 bool pending_removal() { return _pending_removal; } 537 538 void set_pending_removal(bool pending_removal) { 539 if (pending_removal) { 540 assert(!_pending_removal && containing_set() != NULL, 541 "can only set pending removal to true if it's false and " 542 "the region belongs to a region set"); 543 } else { 544 assert( _pending_removal && containing_set() == NULL, 545 "can only set pending removal to false if it's true and " 546 "the region does not belong to a region set"); 547 } 548 549 _pending_removal = pending_removal; 550 } 551 552 HeapRegion* get_next_young_region() { return _next_young_region; } 553 void set_next_young_region(HeapRegion* hr) { 554 _next_young_region = hr; 555 } 556 557 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 558 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 559 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 560 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 561 562 HeapWord* orig_end() { return _orig_end; } 563 564 // Allows logical separation between objects allocated before and after. 565 void save_marks(); 566 567 // Reset HR stuff to default values. 568 void hr_clear(bool par, bool clear_space); 569 void par_clear(); 570 571 void initialize(MemRegion mr, bool clear_space, bool mangle_space); 572 573 // Get the start of the unmarked area in this region. 574 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 575 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 576 577 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects 578 // allocated in the current region before the last call to "save_mark". 579 void oop_before_save_marks_iterate(OopClosure* cl); 580 581 // Note the start or end of marking. This tells the heap region 582 // that the collector is about to start or has finished (concurrently) 583 // marking the heap. 584 585 // Note the start of a marking phase. Record the 586 // start of the unmarked area of the region here. 587 void note_start_of_marking(bool during_initial_mark) { 588 init_top_at_conc_mark_count(); 589 _next_marked_bytes = 0; 590 if (during_initial_mark && is_young() && !is_survivor()) 591 _next_top_at_mark_start = bottom(); 592 else 593 _next_top_at_mark_start = top(); 594 } 595 596 // Note the end of a marking phase. Install the start of 597 // the unmarked area that was captured at start of marking. 598 void note_end_of_marking() { 599 _prev_top_at_mark_start = _next_top_at_mark_start; 600 _prev_marked_bytes = _next_marked_bytes; 601 _next_marked_bytes = 0; 602 603 guarantee(_prev_marked_bytes <= 604 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize, 605 "invariant"); 606 } 607 608 // After an evacuation, we need to update _next_top_at_mark_start 609 // to be the current top. Note this is only valid if we have only 610 // ever evacuated into this region. If we evacuate, allocate, and 611 // then evacuate we are in deep doodoo. 612 void note_end_of_copying() { 613 assert(top() >= _next_top_at_mark_start, "Increase only"); 614 _next_top_at_mark_start = top(); 615 } 616 617 // Returns "false" iff no object in the region was allocated when the 618 // last mark phase ended. 619 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 620 621 // If "is_marked()" is true, then this is the index of the region in 622 // an array constructed at the end of marking of the regions in a 623 // "desirability" order. 624 int sort_index() { 625 return _sort_index; 626 } 627 void set_sort_index(int i) { 628 _sort_index = i; 629 } 630 631 void init_top_at_conc_mark_count() { 632 _top_at_conc_mark_count = bottom(); 633 } 634 635 void set_top_at_conc_mark_count(HeapWord *cur) { 636 assert(bottom() <= cur && cur <= end(), "Sanity."); 637 _top_at_conc_mark_count = cur; 638 } 639 640 HeapWord* top_at_conc_mark_count() { 641 return _top_at_conc_mark_count; 642 } 643 644 void reset_during_compaction() { 645 guarantee( isHumongous() && startsHumongous(), 646 "should only be called for humongous regions"); 647 648 zero_marked_bytes(); 649 init_top_at_mark_start(); 650 } 651 652 // <PREDICTION> 653 void calc_gc_efficiency(void); 654 double gc_efficiency() { return _gc_efficiency;} 655 // </PREDICTION> 656 657 bool is_young() const { return _young_type != NotYoung; } 658 bool is_survivor() const { return _young_type == Survivor; } 659 660 int young_index_in_cset() const { return _young_index_in_cset; } 661 void set_young_index_in_cset(int index) { 662 assert( (index == -1) || is_young(), "pre-condition" ); 663 _young_index_in_cset = index; 664 } 665 666 int age_in_surv_rate_group() { 667 assert( _surv_rate_group != NULL, "pre-condition" ); 668 assert( _age_index > -1, "pre-condition" ); 669 return _surv_rate_group->age_in_group(_age_index); 670 } 671 672 void record_surv_words_in_group(size_t words_survived) { 673 assert( _surv_rate_group != NULL, "pre-condition" ); 674 assert( _age_index > -1, "pre-condition" ); 675 int age_in_group = age_in_surv_rate_group(); 676 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 677 } 678 679 int age_in_surv_rate_group_cond() { 680 if (_surv_rate_group != NULL) 681 return age_in_surv_rate_group(); 682 else 683 return -1; 684 } 685 686 SurvRateGroup* surv_rate_group() { 687 return _surv_rate_group; 688 } 689 690 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 691 assert( surv_rate_group != NULL, "pre-condition" ); 692 assert( _surv_rate_group == NULL, "pre-condition" ); 693 assert( is_young(), "pre-condition" ); 694 695 _surv_rate_group = surv_rate_group; 696 _age_index = surv_rate_group->next_age_index(); 697 } 698 699 void uninstall_surv_rate_group() { 700 if (_surv_rate_group != NULL) { 701 assert( _age_index > -1, "pre-condition" ); 702 assert( is_young(), "pre-condition" ); 703 704 _surv_rate_group = NULL; 705 _age_index = -1; 706 } else { 707 assert( _age_index == -1, "pre-condition" ); 708 } 709 } 710 711 void set_young() { set_young_type(Young); } 712 713 void set_survivor() { set_young_type(Survivor); } 714 715 void set_not_young() { set_young_type(NotYoung); } 716 717 // Determine if an object has been allocated since the last 718 // mark performed by the collector. This returns true iff the object 719 // is within the unmarked area of the region. 720 bool obj_allocated_since_prev_marking(oop obj) const { 721 return (HeapWord *) obj >= prev_top_at_mark_start(); 722 } 723 bool obj_allocated_since_next_marking(oop obj) const { 724 return (HeapWord *) obj >= next_top_at_mark_start(); 725 } 726 727 // For parallel heapRegion traversal. 728 bool claimHeapRegion(int claimValue); 729 jint claim_value() { return _claimed; } 730 // Use this carefully: only when you're sure no one is claiming... 731 void set_claim_value(int claimValue) { _claimed = claimValue; } 732 733 // Returns the "evacuation_failed" property of the region. 734 bool evacuation_failed() { return _evacuation_failed; } 735 736 // Sets the "evacuation_failed" property of the region. 737 void set_evacuation_failed(bool b) { 738 _evacuation_failed = b; 739 740 if (b) { 741 init_top_at_conc_mark_count(); 742 _next_marked_bytes = 0; 743 } 744 } 745 746 // Requires that "mr" be entirely within the region. 747 // Apply "cl->do_object" to all objects that intersect with "mr". 748 // If the iteration encounters an unparseable portion of the region, 749 // or if "cl->abort()" is true after a closure application, 750 // terminate the iteration and return the address of the start of the 751 // subregion that isn't done. (The two can be distinguished by querying 752 // "cl->abort()".) Return of "NULL" indicates that the iteration 753 // completed. 754 HeapWord* 755 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 756 757 // filter_young: if true and the region is a young region then we 758 // skip the iteration. 759 // card_ptr: if not NULL, and we decide that the card is not young 760 // and we iterate over it, we'll clean the card before we start the 761 // iteration. 762 HeapWord* 763 oops_on_card_seq_iterate_careful(MemRegion mr, 764 FilterOutOfRegionClosure* cl, 765 bool filter_young, 766 jbyte* card_ptr); 767 768 // A version of block start that is guaranteed to find *some* block 769 // boundary at or before "p", but does not object iteration, and may 770 // therefore be used safely when the heap is unparseable. 771 HeapWord* block_start_careful(const void* p) const { 772 return _offsets.block_start_careful(p); 773 } 774 775 // Requires that "addr" is within the region. Returns the start of the 776 // first ("careful") block that starts at or after "addr", or else the 777 // "end" of the region if there is no such block. 778 HeapWord* next_block_start_careful(HeapWord* addr); 779 780 size_t recorded_rs_length() const { return _recorded_rs_length; } 781 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 782 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 783 784 void set_recorded_rs_length(size_t rs_length) { 785 _recorded_rs_length = rs_length; 786 } 787 788 void set_predicted_elapsed_time_ms(double ms) { 789 _predicted_elapsed_time_ms = ms; 790 } 791 792 void set_predicted_bytes_to_copy(size_t bytes) { 793 _predicted_bytes_to_copy = bytes; 794 } 795 796 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ 797 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); 798 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL) 799 800 CompactibleSpace* next_compaction_space() const; 801 802 virtual void reset_after_compaction(); 803 804 void print() const; 805 void print_on(outputStream* st) const; 806 807 // vo == UsePrevMarking -> use "prev" marking information, 808 // vo == UseNextMarking -> use "next" marking information 809 // vo == UseMarkWord -> use the mark word in the object header 810 // 811 // NOTE: Only the "prev" marking information is guaranteed to be 812 // consistent most of the time, so most calls to this should use 813 // vo == UsePrevMarking. 814 // Currently, there is only one case where this is called with 815 // vo == UseNextMarking, which is to verify the "next" marking 816 // information at the end of remark. 817 // Currently there is only one place where this is called with 818 // vo == UseMarkWord, which is to verify the marking during a 819 // full GC. 820 void verify(bool allow_dirty, VerifyOption vo, bool *failures) const; 821 822 // Override; it uses the "prev" marking information 823 virtual void verify(bool allow_dirty) const; 824 }; 825 826 // HeapRegionClosure is used for iterating over regions. 827 // Terminates the iteration when the "doHeapRegion" method returns "true". 828 class HeapRegionClosure : public StackObj { 829 friend class HeapRegionSeq; 830 friend class G1CollectedHeap; 831 832 bool _complete; 833 void incomplete() { _complete = false; } 834 835 public: 836 HeapRegionClosure(): _complete(true) {} 837 838 // Typically called on each region until it returns true. 839 virtual bool doHeapRegion(HeapRegion* r) = 0; 840 841 // True after iteration if the closure was applied to all heap regions 842 // and returned "false" in all cases. 843 bool complete() { return _complete; } 844 }; 845 846 #endif // SERIALGC 847 848 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP