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 }; 120 121 122 // The complicating factor is that BlockOffsetTable diverged 123 // significantly, and we need functionality that is only in the G1 version. 124 // So I copied that code, which led to an alternate G1 version of 125 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 126 // be reconciled, then G1OffsetTableContigSpace could go away. 127 128 // The idea behind time stamps is the following. Doing a save_marks on 129 // all regions at every GC pause is time consuming (if I remember 130 // well, 10ms or so). So, we would like to do that only for regions 131 // that are GC alloc regions. To achieve this, we use time 132 // stamps. For every evacuation pause, G1CollectedHeap generates a 133 // unique time stamp (essentially a counter that gets 134 // incremented). Every time we want to call save_marks on a region, 135 // we set the saved_mark_word to top and also copy the current GC 136 // time stamp to the time stamp field of the space. Reading the 137 // saved_mark_word involves checking the time stamp of the 138 // region. If it is the same as the current GC time stamp, then we 139 // can safely read the saved_mark_word field, as it is valid. If the 140 // time stamp of the region is not the same as the current GC time 141 // stamp, then we instead read top, as the saved_mark_word field is 142 // invalid. Time stamps (on the regions and also on the 143 // G1CollectedHeap) are reset at every cleanup (we iterate over 144 // the regions anyway) and at the end of a Full GC. The current scheme 145 // that uses sequential unsigned ints will fail only if we have 4b 146 // evacuation pauses between two cleanups, which is _highly_ unlikely. 147 148 class G1OffsetTableContigSpace: public ContiguousSpace { 149 friend class VMStructs; 150 protected: 151 G1BlockOffsetArrayContigSpace _offsets; 152 Mutex _par_alloc_lock; 153 volatile unsigned _gc_time_stamp; 154 // When we need to retire an allocation region, while other threads 155 // are also concurrently trying to allocate into it, we typically 156 // allocate a dummy object at the end of the region to ensure that 157 // no more allocations can take place in it. However, sometimes we 158 // want to know where the end of the last "real" object we allocated 159 // into the region was and this is what this keeps track. 160 HeapWord* _pre_dummy_top; 161 162 public: 163 // Constructor. If "is_zeroed" is true, the MemRegion "mr" may be 164 // assumed to contain zeros. 165 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 166 MemRegion mr, bool is_zeroed = false); 167 168 void set_bottom(HeapWord* value); 169 void set_end(HeapWord* value); 170 171 virtual HeapWord* saved_mark_word() const; 172 virtual void set_saved_mark(); 173 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 174 175 // See the comment above in the declaration of _pre_dummy_top for an 176 // explanation of what it is. 177 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 178 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 179 _pre_dummy_top = pre_dummy_top; 180 } 181 HeapWord* pre_dummy_top() { 182 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 183 } 184 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 185 186 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 187 virtual void clear(bool mangle_space); 188 189 HeapWord* block_start(const void* p); 190 HeapWord* block_start_const(const void* p) const; 191 192 // Add offset table update. 193 virtual HeapWord* allocate(size_t word_size); 194 HeapWord* par_allocate(size_t word_size); 195 196 // MarkSweep support phase3 197 virtual HeapWord* initialize_threshold(); 198 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 199 200 virtual void print() const; 201 202 void reset_bot() { 203 _offsets.zero_bottom_entry(); 204 _offsets.initialize_threshold(); 205 } 206 207 void update_bot_for_object(HeapWord* start, size_t word_size) { 208 _offsets.alloc_block(start, word_size); 209 } 210 211 void print_bot_on(outputStream* out) { 212 _offsets.print_on(out); 213 } 214 }; 215 216 class HeapRegion: public G1OffsetTableContigSpace { 217 friend class VMStructs; 218 private: 219 220 enum HumongousType { 221 NotHumongous = 0, 222 StartsHumongous, 223 ContinuesHumongous 224 }; 225 226 // The next filter kind that should be used for a "new_dcto_cl" call with 227 // the "traditional" signature. 228 HeapRegionDCTOC::FilterKind _next_fk; 229 230 // Requires that the region "mr" be dense with objects, and begin and end 231 // with an object. 232 void oops_in_mr_iterate(MemRegion mr, OopClosure* cl); 233 234 // The remembered set for this region. 235 // (Might want to make this "inline" later, to avoid some alloc failure 236 // issues.) 237 HeapRegionRemSet* _rem_set; 238 239 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 240 241 protected: 242 // The index of this region in the heap region sequence. 243 size_t _hrs_index; 244 245 HumongousType _humongous_type; 246 // For a humongous region, region in which it starts. 247 HeapRegion* _humongous_start_region; 248 // For the start region of a humongous sequence, it's original end(). 249 HeapWord* _orig_end; 250 251 // True iff the region is in current collection_set. 252 bool _in_collection_set; 253 254 // Is this or has it been an allocation region in the current collection 255 // pause. 256 bool _is_gc_alloc_region; 257 258 // True iff an attempt to evacuate an object in the region failed. 259 bool _evacuation_failed; 260 261 // A heap region may be a member one of a number of special subsets, each 262 // represented as linked lists through the field below. Currently, these 263 // sets include: 264 // The collection set. 265 // The set of allocation regions used in a collection pause. 266 // Spaces that may contain gray objects. 267 HeapRegion* _next_in_special_set; 268 269 // next region in the young "generation" region set 270 HeapRegion* _next_young_region; 271 272 // Next region whose cards need cleaning 273 HeapRegion* _next_dirty_cards_region; 274 275 // Fields used by the HeapRegionSetBase class and subclasses. 276 HeapRegion* _next; 277 #ifdef ASSERT 278 HeapRegionSetBase* _containing_set; 279 #endif // ASSERT 280 bool _pending_removal; 281 282 // For parallel heapRegion traversal. 283 jint _claimed; 284 285 // We use concurrent marking to determine the amount of live data 286 // in each heap region. 287 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 288 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 289 290 // See "sort_index" method. -1 means is not in the array. 291 int _sort_index; 292 293 // <PREDICTION> 294 double _gc_efficiency; 295 // </PREDICTION> 296 297 enum YoungType { 298 NotYoung, // a region is not young 299 Young, // a region is young 300 Survivor // a region is young and it contains survivors 301 }; 302 303 volatile YoungType _young_type; 304 int _young_index_in_cset; 305 SurvRateGroup* _surv_rate_group; 306 int _age_index; 307 308 // The start of the unmarked area. The unmarked area extends from this 309 // word until the top and/or end of the region, and is the part 310 // of the region for which no marking was done, i.e. objects may 311 // have been allocated in this part since the last mark phase. 312 // "prev" is the top at the start of the last completed marking. 313 // "next" is the top at the start of the in-progress marking (if any.) 314 HeapWord* _prev_top_at_mark_start; 315 HeapWord* _next_top_at_mark_start; 316 // If a collection pause is in progress, this is the top at the start 317 // of that pause. 318 319 // We've counted the marked bytes of objects below here. 320 HeapWord* _top_at_conc_mark_count; 321 322 void init_top_at_mark_start() { 323 assert(_prev_marked_bytes == 0 && 324 _next_marked_bytes == 0, 325 "Must be called after zero_marked_bytes."); 326 HeapWord* bot = bottom(); 327 _prev_top_at_mark_start = bot; 328 _next_top_at_mark_start = bot; 329 _top_at_conc_mark_count = bot; 330 } 331 332 void set_young_type(YoungType new_type) { 333 //assert(_young_type != new_type, "setting the same type" ); 334 // TODO: add more assertions here 335 _young_type = new_type; 336 } 337 338 // Cached attributes used in the collection set policy information 339 340 // The RSet length that was added to the total value 341 // for the collection set. 342 size_t _recorded_rs_length; 343 344 // The predicted elapsed time that was added to total value 345 // for the collection set. 346 double _predicted_elapsed_time_ms; 347 348 // The predicted number of bytes to copy that was added to 349 // the total value for the collection set. 350 size_t _predicted_bytes_to_copy; 351 352 public: 353 // If "is_zeroed" is "true", the region "mr" can be assumed to contain zeros. 354 HeapRegion(size_t hrs_index, 355 G1BlockOffsetSharedArray* sharedOffsetArray, 356 MemRegion mr, bool is_zeroed); 357 358 static int LogOfHRGrainBytes; 359 static int LogOfHRGrainWords; 360 // The normal type of these should be size_t. However, they used to 361 // be members of an enum before and they are assumed by the 362 // compilers to be ints. To avoid going and fixing all their uses, 363 // I'm declaring them as ints. I'm not anticipating heap region 364 // sizes to reach anywhere near 2g, so using an int here is safe. 365 static int GrainBytes; 366 static int GrainWords; 367 static int CardsPerRegion; 368 369 // It sets up the heap region size (GrainBytes / GrainWords), as 370 // well as other related fields that are based on the heap region 371 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 372 // CardsPerRegion). All those fields are considered constant 373 // throughout the JVM's execution, therefore they should only be set 374 // up once during initialization time. 375 static void setup_heap_region_size(uintx min_heap_size); 376 377 enum ClaimValues { 378 InitialClaimValue = 0, 379 FinalCountClaimValue = 1, 380 NoteEndClaimValue = 2, 381 ScrubRemSetClaimValue = 3, 382 ParVerifyClaimValue = 4, 383 RebuildRSClaimValue = 5 384 }; 385 386 inline HeapWord* par_allocate_no_bot_updates(size_t word_size) { 387 assert(is_young(), "we can only skip BOT updates on young regions"); 388 return ContiguousSpace::par_allocate(word_size); 389 } 390 inline HeapWord* allocate_no_bot_updates(size_t word_size) { 391 assert(is_young(), "we can only skip BOT updates on young regions"); 392 return ContiguousSpace::allocate(word_size); 393 } 394 395 // If this region is a member of a HeapRegionSeq, the index in that 396 // sequence, otherwise -1. 397 size_t hrs_index() const { return _hrs_index; } 398 399 // The number of bytes marked live in the region in the last marking phase. 400 size_t marked_bytes() { return _prev_marked_bytes; } 401 size_t live_bytes() { 402 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 403 } 404 405 // The number of bytes counted in the next marking. 406 size_t next_marked_bytes() { return _next_marked_bytes; } 407 // The number of bytes live wrt the next marking. 408 size_t next_live_bytes() { 409 return 410 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 411 } 412 413 // A lower bound on the amount of garbage bytes in the region. 414 size_t garbage_bytes() { 415 size_t used_at_mark_start_bytes = 416 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 417 assert(used_at_mark_start_bytes >= marked_bytes(), 418 "Can't mark more than we have."); 419 return used_at_mark_start_bytes - marked_bytes(); 420 } 421 422 // An upper bound on the number of live bytes in the region. 423 size_t max_live_bytes() { return used() - garbage_bytes(); } 424 425 void add_to_marked_bytes(size_t incr_bytes) { 426 _next_marked_bytes = _next_marked_bytes + incr_bytes; 427 guarantee( _next_marked_bytes <= used(), "invariant" ); 428 } 429 430 void zero_marked_bytes() { 431 _prev_marked_bytes = _next_marked_bytes = 0; 432 } 433 434 bool isHumongous() const { return _humongous_type != NotHumongous; } 435 bool startsHumongous() const { return _humongous_type == StartsHumongous; } 436 bool continuesHumongous() const { return _humongous_type == ContinuesHumongous; } 437 // For a humongous region, region in which it starts. 438 HeapRegion* humongous_start_region() const { 439 return _humongous_start_region; 440 } 441 442 // Makes the current region be a "starts humongous" region, i.e., 443 // the first region in a series of one or more contiguous regions 444 // that will contain a single "humongous" object. The two parameters 445 // are as follows: 446 // 447 // new_top : The new value of the top field of this region which 448 // points to the end of the humongous object that's being 449 // allocated. If there is more than one region in the series, top 450 // will lie beyond this region's original end field and on the last 451 // region in the series. 452 // 453 // new_end : The new value of the end field of this region which 454 // points to the end of the last region in the series. If there is 455 // one region in the series (namely: this one) end will be the same 456 // as the original end of this region. 457 // 458 // Updating top and end as described above makes this region look as 459 // if it spans the entire space taken up by all the regions in the 460 // series and an single allocation moved its top to new_top. This 461 // ensures that the space (capacity / allocated) taken up by all 462 // humongous regions can be calculated by just looking at the 463 // "starts humongous" regions and by ignoring the "continues 464 // humongous" regions. 465 void set_startsHumongous(HeapWord* new_top, HeapWord* new_end); 466 467 // Makes the current region be a "continues humongous' 468 // region. first_hr is the "start humongous" region of the series 469 // which this region will be part of. 470 void set_continuesHumongous(HeapRegion* first_hr); 471 472 // Unsets the humongous-related fields on the region. 473 void set_notHumongous(); 474 475 // If the region has a remembered set, return a pointer to it. 476 HeapRegionRemSet* rem_set() const { 477 return _rem_set; 478 } 479 480 // True iff the region is in current collection_set. 481 bool in_collection_set() const { 482 return _in_collection_set; 483 } 484 void set_in_collection_set(bool b) { 485 _in_collection_set = b; 486 } 487 HeapRegion* next_in_collection_set() { 488 assert(in_collection_set(), "should only invoke on member of CS."); 489 assert(_next_in_special_set == NULL || 490 _next_in_special_set->in_collection_set(), 491 "Malformed CS."); 492 return _next_in_special_set; 493 } 494 void set_next_in_collection_set(HeapRegion* r) { 495 assert(in_collection_set(), "should only invoke on member of CS."); 496 assert(r == NULL || r->in_collection_set(), "Malformed CS."); 497 _next_in_special_set = r; 498 } 499 500 // True iff it is or has been an allocation region in the current 501 // collection pause. 502 bool is_gc_alloc_region() const { 503 return _is_gc_alloc_region; 504 } 505 void set_is_gc_alloc_region(bool b) { 506 _is_gc_alloc_region = b; 507 } 508 HeapRegion* next_gc_alloc_region() { 509 assert(is_gc_alloc_region(), "should only invoke on member of CS."); 510 assert(_next_in_special_set == NULL || 511 _next_in_special_set->is_gc_alloc_region(), 512 "Malformed CS."); 513 return _next_in_special_set; 514 } 515 void set_next_gc_alloc_region(HeapRegion* r) { 516 assert(is_gc_alloc_region(), "should only invoke on member of CS."); 517 assert(r == NULL || r->is_gc_alloc_region(), "Malformed CS."); 518 _next_in_special_set = r; 519 } 520 521 // Methods used by the HeapRegionSetBase class and subclasses. 522 523 // Getter and setter for the next field used to link regions into 524 // linked lists. 525 HeapRegion* next() { return _next; } 526 527 void set_next(HeapRegion* next) { _next = next; } 528 529 // Every region added to a set is tagged with a reference to that 530 // set. This is used for doing consistency checking to make sure that 531 // the contents of a set are as they should be and it's only 532 // available in non-product builds. 533 #ifdef ASSERT 534 void set_containing_set(HeapRegionSetBase* containing_set) { 535 assert((containing_set == NULL && _containing_set != NULL) || 536 (containing_set != NULL && _containing_set == NULL), 537 err_msg("containing_set: "PTR_FORMAT" " 538 "_containing_set: "PTR_FORMAT, 539 containing_set, _containing_set)); 540 541 _containing_set = containing_set; 542 } 543 544 HeapRegionSetBase* containing_set() { return _containing_set; } 545 #else // ASSERT 546 void set_containing_set(HeapRegionSetBase* containing_set) { } 547 548 // containing_set() is only used in asserts so there's no reason 549 // to provide a dummy version of it. 550 #endif // ASSERT 551 552 // If we want to remove regions from a list in bulk we can simply tag 553 // them with the pending_removal tag and call the 554 // remove_all_pending() method on the list. 555 556 bool pending_removal() { return _pending_removal; } 557 558 void set_pending_removal(bool pending_removal) { 559 if (pending_removal) { 560 assert(!_pending_removal && containing_set() != NULL, 561 "can only set pending removal to true if it's false and " 562 "the region belongs to a region set"); 563 } else { 564 assert( _pending_removal && containing_set() == NULL, 565 "can only set pending removal to false if it's true and " 566 "the region does not belong to a region set"); 567 } 568 569 _pending_removal = pending_removal; 570 } 571 572 HeapRegion* get_next_young_region() { return _next_young_region; } 573 void set_next_young_region(HeapRegion* hr) { 574 _next_young_region = hr; 575 } 576 577 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 578 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 579 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 580 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 581 582 HeapWord* orig_end() { return _orig_end; } 583 584 // Allows logical separation between objects allocated before and after. 585 void save_marks(); 586 587 // Reset HR stuff to default values. 588 void hr_clear(bool par, bool clear_space); 589 void par_clear(); 590 591 void initialize(MemRegion mr, bool clear_space, bool mangle_space); 592 593 // Get the start of the unmarked area in this region. 594 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 595 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 596 597 // Apply "cl->do_oop" to (the addresses of) all reference fields in objects 598 // allocated in the current region before the last call to "save_mark". 599 void oop_before_save_marks_iterate(OopClosure* cl); 600 601 // This call determines the "filter kind" argument that will be used for 602 // the next call to "new_dcto_cl" on this region with the "traditional" 603 // signature (i.e., the call below.) The default, in the absence of a 604 // preceding call to this method, is "NoFilterKind", and a call to this 605 // method is necessary for each such call, or else it reverts to the 606 // default. 607 // (This is really ugly, but all other methods I could think of changed a 608 // lot of main-line code for G1.) 609 void set_next_filter_kind(HeapRegionDCTOC::FilterKind nfk) { 610 _next_fk = nfk; 611 } 612 613 DirtyCardToOopClosure* 614 new_dcto_closure(OopClosure* cl, 615 CardTableModRefBS::PrecisionStyle precision, 616 HeapRegionDCTOC::FilterKind fk); 617 618 #if WHASSUP 619 DirtyCardToOopClosure* 620 new_dcto_closure(OopClosure* cl, 621 CardTableModRefBS::PrecisionStyle precision, 622 HeapWord* boundary) { 623 assert(boundary == NULL, "This arg doesn't make sense here."); 624 DirtyCardToOopClosure* res = new_dcto_closure(cl, precision, _next_fk); 625 _next_fk = HeapRegionDCTOC::NoFilterKind; 626 return res; 627 } 628 #endif 629 630 // 631 // Note the start or end of marking. This tells the heap region 632 // that the collector is about to start or has finished (concurrently) 633 // marking the heap. 634 // 635 636 // Note the start of a marking phase. Record the 637 // start of the unmarked area of the region here. 638 void note_start_of_marking(bool during_initial_mark) { 639 init_top_at_conc_mark_count(); 640 _next_marked_bytes = 0; 641 if (during_initial_mark && is_young() && !is_survivor()) 642 _next_top_at_mark_start = bottom(); 643 else 644 _next_top_at_mark_start = top(); 645 } 646 647 // Note the end of a marking phase. Install the start of 648 // the unmarked area that was captured at start of marking. 649 void note_end_of_marking() { 650 _prev_top_at_mark_start = _next_top_at_mark_start; 651 _prev_marked_bytes = _next_marked_bytes; 652 _next_marked_bytes = 0; 653 654 guarantee(_prev_marked_bytes <= 655 (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize, 656 "invariant"); 657 } 658 659 // After an evacuation, we need to update _next_top_at_mark_start 660 // to be the current top. Note this is only valid if we have only 661 // ever evacuated into this region. If we evacuate, allocate, and 662 // then evacuate we are in deep doodoo. 663 void note_end_of_copying() { 664 assert(top() >= _next_top_at_mark_start, "Increase only"); 665 _next_top_at_mark_start = top(); 666 } 667 668 // Returns "false" iff no object in the region was allocated when the 669 // last mark phase ended. 670 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 671 672 // If "is_marked()" is true, then this is the index of the region in 673 // an array constructed at the end of marking of the regions in a 674 // "desirability" order. 675 int sort_index() { 676 return _sort_index; 677 } 678 void set_sort_index(int i) { 679 _sort_index = i; 680 } 681 682 void init_top_at_conc_mark_count() { 683 _top_at_conc_mark_count = bottom(); 684 } 685 686 void set_top_at_conc_mark_count(HeapWord *cur) { 687 assert(bottom() <= cur && cur <= end(), "Sanity."); 688 _top_at_conc_mark_count = cur; 689 } 690 691 HeapWord* top_at_conc_mark_count() { 692 return _top_at_conc_mark_count; 693 } 694 695 void reset_during_compaction() { 696 guarantee( isHumongous() && startsHumongous(), 697 "should only be called for humongous regions"); 698 699 zero_marked_bytes(); 700 init_top_at_mark_start(); 701 } 702 703 // <PREDICTION> 704 void calc_gc_efficiency(void); 705 double gc_efficiency() { return _gc_efficiency;} 706 // </PREDICTION> 707 708 bool is_young() const { return _young_type != NotYoung; } 709 bool is_survivor() const { return _young_type == Survivor; } 710 711 int young_index_in_cset() const { return _young_index_in_cset; } 712 void set_young_index_in_cset(int index) { 713 assert( (index == -1) || is_young(), "pre-condition" ); 714 _young_index_in_cset = index; 715 } 716 717 int age_in_surv_rate_group() { 718 assert( _surv_rate_group != NULL, "pre-condition" ); 719 assert( _age_index > -1, "pre-condition" ); 720 return _surv_rate_group->age_in_group(_age_index); 721 } 722 723 void record_surv_words_in_group(size_t words_survived) { 724 assert( _surv_rate_group != NULL, "pre-condition" ); 725 assert( _age_index > -1, "pre-condition" ); 726 int age_in_group = age_in_surv_rate_group(); 727 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 728 } 729 730 int age_in_surv_rate_group_cond() { 731 if (_surv_rate_group != NULL) 732 return age_in_surv_rate_group(); 733 else 734 return -1; 735 } 736 737 SurvRateGroup* surv_rate_group() { 738 return _surv_rate_group; 739 } 740 741 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 742 assert( surv_rate_group != NULL, "pre-condition" ); 743 assert( _surv_rate_group == NULL, "pre-condition" ); 744 assert( is_young(), "pre-condition" ); 745 746 _surv_rate_group = surv_rate_group; 747 _age_index = surv_rate_group->next_age_index(); 748 } 749 750 void uninstall_surv_rate_group() { 751 if (_surv_rate_group != NULL) { 752 assert( _age_index > -1, "pre-condition" ); 753 assert( is_young(), "pre-condition" ); 754 755 _surv_rate_group = NULL; 756 _age_index = -1; 757 } else { 758 assert( _age_index == -1, "pre-condition" ); 759 } 760 } 761 762 void set_young() { set_young_type(Young); } 763 764 void set_survivor() { set_young_type(Survivor); } 765 766 void set_not_young() { set_young_type(NotYoung); } 767 768 // Determine if an object has been allocated since the last 769 // mark performed by the collector. This returns true iff the object 770 // is within the unmarked area of the region. 771 bool obj_allocated_since_prev_marking(oop obj) const { 772 return (HeapWord *) obj >= prev_top_at_mark_start(); 773 } 774 bool obj_allocated_since_next_marking(oop obj) const { 775 return (HeapWord *) obj >= next_top_at_mark_start(); 776 } 777 778 // For parallel heapRegion traversal. 779 bool claimHeapRegion(int claimValue); 780 jint claim_value() { return _claimed; } 781 // Use this carefully: only when you're sure no one is claiming... 782 void set_claim_value(int claimValue) { _claimed = claimValue; } 783 784 // Returns the "evacuation_failed" property of the region. 785 bool evacuation_failed() { return _evacuation_failed; } 786 787 // Sets the "evacuation_failed" property of the region. 788 void set_evacuation_failed(bool b) { 789 _evacuation_failed = b; 790 791 if (b) { 792 init_top_at_conc_mark_count(); 793 _next_marked_bytes = 0; 794 } 795 } 796 797 // Requires that "mr" be entirely within the region. 798 // Apply "cl->do_object" to all objects that intersect with "mr". 799 // If the iteration encounters an unparseable portion of the region, 800 // or if "cl->abort()" is true after a closure application, 801 // terminate the iteration and return the address of the start of the 802 // subregion that isn't done. (The two can be distinguished by querying 803 // "cl->abort()".) Return of "NULL" indicates that the iteration 804 // completed. 805 HeapWord* 806 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 807 808 // filter_young: if true and the region is a young region then we 809 // skip the iteration. 810 // card_ptr: if not NULL, and we decide that the card is not young 811 // and we iterate over it, we'll clean the card before we start the 812 // iteration. 813 HeapWord* 814 oops_on_card_seq_iterate_careful(MemRegion mr, 815 FilterOutOfRegionClosure* cl, 816 bool filter_young, 817 jbyte* card_ptr); 818 819 // A version of block start that is guaranteed to find *some* block 820 // boundary at or before "p", but does not object iteration, and may 821 // therefore be used safely when the heap is unparseable. 822 HeapWord* block_start_careful(const void* p) const { 823 return _offsets.block_start_careful(p); 824 } 825 826 // Requires that "addr" is within the region. Returns the start of the 827 // first ("careful") block that starts at or after "addr", or else the 828 // "end" of the region if there is no such block. 829 HeapWord* next_block_start_careful(HeapWord* addr); 830 831 size_t recorded_rs_length() const { return _recorded_rs_length; } 832 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 833 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 834 835 void set_recorded_rs_length(size_t rs_length) { 836 _recorded_rs_length = rs_length; 837 } 838 839 void set_predicted_elapsed_time_ms(double ms) { 840 _predicted_elapsed_time_ms = ms; 841 } 842 843 void set_predicted_bytes_to_copy(size_t bytes) { 844 _predicted_bytes_to_copy = bytes; 845 } 846 847 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ 848 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); 849 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DECL) 850 851 CompactibleSpace* next_compaction_space() const; 852 853 virtual void reset_after_compaction(); 854 855 void print() const; 856 void print_on(outputStream* st) const; 857 858 // vo == UsePrevMarking -> use "prev" marking information, 859 // vo == UseNextMarking -> use "next" marking information 860 // vo == UseMarkWord -> use the mark word in the object header 861 // 862 // NOTE: Only the "prev" marking information is guaranteed to be 863 // consistent most of the time, so most calls to this should use 864 // vo == UsePrevMarking. 865 // Currently, there is only one case where this is called with 866 // vo == UseNextMarking, which is to verify the "next" marking 867 // information at the end of remark. 868 // Currently there is only one place where this is called with 869 // vo == UseMarkWord, which is to verify the marking during a 870 // full GC. 871 void verify(bool allow_dirty, VerifyOption vo, bool *failures) const; 872 873 // Override; it uses the "prev" marking information 874 virtual void verify(bool allow_dirty) const; 875 }; 876 877 // HeapRegionClosure is used for iterating over regions. 878 // Terminates the iteration when the "doHeapRegion" method returns "true". 879 class HeapRegionClosure : public StackObj { 880 friend class HeapRegionSeq; 881 friend class G1CollectedHeap; 882 883 bool _complete; 884 void incomplete() { _complete = false; } 885 886 public: 887 HeapRegionClosure(): _complete(true) {} 888 889 // Typically called on each region until it returns true. 890 virtual bool doHeapRegion(HeapRegion* r) = 0; 891 892 // True after iteration if the closure was applied to all heap regions 893 // and returned "false" in all cases. 894 bool complete() { return _complete; } 895 }; 896 897 #endif // SERIALGC 898 899 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP