1 /* 2 * Copyright (c) 2001, 2015, 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_G1_HEAPREGION_HPP 26 #define SHARE_VM_GC_G1_HEAPREGION_HPP 27 28 #include "gc/g1/g1AllocationContext.hpp" 29 #include "gc/g1/g1BlockOffsetTable.hpp" 30 #include "gc/g1/heapRegionType.hpp" 31 #include "gc/g1/survRateGroup.hpp" 32 #include "gc/shared/ageTable.hpp" 33 #include "gc/shared/spaceDecorator.hpp" 34 #include "gc/shared/watermark.hpp" 35 #include "utilities/macros.hpp" 36 37 // A HeapRegion is the smallest piece of a G1CollectedHeap that 38 // can be collected independently. 39 40 // NOTE: Although a HeapRegion is a Space, its 41 // Space::initDirtyCardClosure method must not be called. 42 // The problem is that the existence of this method breaks 43 // the independence of barrier sets from remembered sets. 44 // The solution is to remove this method from the definition 45 // of a Space. 46 47 class G1CollectedHeap; 48 class HeapRegionRemSet; 49 class HeapRegionRemSetIterator; 50 class HeapRegion; 51 class HeapRegionSetBase; 52 class nmethod; 53 54 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]" 55 #define HR_FORMAT_PARAMS(_hr_) \ 56 (_hr_)->hrm_index(), \ 57 (_hr_)->get_short_type_str(), \ 58 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 59 60 // sentinel value for hrm_index 61 #define G1_NO_HRM_INDEX ((uint) -1) 62 63 // A dirty card to oop closure for heap regions. It 64 // knows how to get the G1 heap and how to use the bitmap 65 // in the concurrent marker used by G1 to filter remembered 66 // sets. 67 68 class HeapRegionDCTOC : public DirtyCardToOopClosure { 69 private: 70 HeapRegion* _hr; 71 G1ParPushHeapRSClosure* _rs_scan; 72 G1CollectedHeap* _g1; 73 74 // Walk the given memory region from bottom to (actual) top 75 // looking for objects and applying the oop closure (_cl) to 76 // them. The base implementation of this treats the area as 77 // blocks, where a block may or may not be an object. Sub- 78 // classes should override this to provide more accurate 79 // or possibly more efficient walking. 80 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); 81 82 public: 83 HeapRegionDCTOC(G1CollectedHeap* g1, 84 HeapRegion* hr, 85 G1ParPushHeapRSClosure* cl, 86 CardTableModRefBS::PrecisionStyle precision); 87 }; 88 89 // The complicating factor is that BlockOffsetTable diverged 90 // significantly, and we need functionality that is only in the G1 version. 91 // So I copied that code, which led to an alternate G1 version of 92 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 93 // be reconciled, then G1OffsetTableContigSpace could go away. 94 95 // The idea behind time stamps is the following. We want to keep track of 96 // the highest address where it's safe to scan objects for each region. 97 // This is only relevant for current GC alloc regions so we keep a time stamp 98 // per region to determine if the region has been allocated during the current 99 // GC or not. If the time stamp is current we report a scan_top value which 100 // was saved at the end of the previous GC for retained alloc regions and which is 101 // equal to the bottom for all other regions. 102 // There is a race between card scanners and allocating gc workers where we must ensure 103 // that card scanners do not read the memory allocated by the gc workers. 104 // In order to enforce that, we must not return a value of _top which is more recent than the 105 // time stamp. This is due to the fact that a region may become a gc alloc region at 106 // some point after we've read the timestamp value as being < the current time stamp. 107 // The time stamps are re-initialized to zero at cleanup and at Full GCs. 108 // The current scheme that uses sequential unsigned ints will fail only if we have 4b 109 // evacuation pauses between two cleanups, which is _highly_ unlikely. 110 class G1OffsetTableContigSpace: public CompactibleSpace { 111 friend class VMStructs; 112 HeapWord* volatile _top; 113 HeapWord* volatile _scan_top; 114 protected: 115 G1BlockOffsetArrayContigSpace _offsets; 116 Mutex _par_alloc_lock; 117 volatile unsigned _gc_time_stamp; 118 // When we need to retire an allocation region, while other threads 119 // are also concurrently trying to allocate into it, we typically 120 // allocate a dummy object at the end of the region to ensure that 121 // no more allocations can take place in it. However, sometimes we 122 // want to know where the end of the last "real" object we allocated 123 // into the region was and this is what this keeps track. 124 HeapWord* _pre_dummy_top; 125 126 public: 127 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 128 MemRegion mr); 129 130 void set_top(HeapWord* value) { _top = value; } 131 HeapWord* top() const { return _top; } 132 133 protected: 134 // Reset the G1OffsetTableContigSpace. 135 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 136 137 HeapWord* volatile* top_addr() { return &_top; } 138 // Try to allocate at least min_word_size and up to desired_size from this Space. 139 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 140 // space allocated. 141 // This version assumes that all allocation requests to this Space are properly 142 // synchronized. 143 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 144 // Try to allocate at least min_word_size and up to desired_size from this Space. 145 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 146 // space allocated. 147 // This version synchronizes with other calls to par_allocate_impl(). 148 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 149 150 public: 151 void reset_after_compaction() { set_top(compaction_top()); } 152 153 size_t used() const { return byte_size(bottom(), top()); } 154 size_t free() const { return byte_size(top(), end()); } 155 bool is_free_block(const HeapWord* p) const { return p >= top(); } 156 157 MemRegion used_region() const { return MemRegion(bottom(), top()); } 158 159 void object_iterate(ObjectClosure* blk); 160 void safe_object_iterate(ObjectClosure* blk); 161 162 void set_bottom(HeapWord* value); 163 void set_end(HeapWord* value); 164 165 void mangle_unused_area() PRODUCT_RETURN; 166 void mangle_unused_area_complete() PRODUCT_RETURN; 167 168 HeapWord* scan_top() const; 169 void record_timestamp(); 170 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 171 unsigned get_gc_time_stamp() { return _gc_time_stamp; } 172 void record_retained_region(); 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 clear(bool mangle_space); 186 187 HeapWord* block_start(const void* p); 188 HeapWord* block_start_const(const void* p) const; 189 190 // Allocation (return NULL if full). Assumes the caller has established 191 // mutually exclusive access to the space. 192 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 193 // Allocation (return NULL if full). Enforces mutual exclusion internally. 194 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 195 196 virtual HeapWord* allocate(size_t word_size); 197 virtual HeapWord* par_allocate(size_t word_size); 198 199 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; } 200 201 // MarkSweep support phase3 202 virtual HeapWord* initialize_threshold(); 203 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 204 205 virtual void print() const; 206 207 void reset_bot() { 208 _offsets.reset_bot(); 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 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class 219 template <typename SpaceType> 220 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp); 221 private: 222 223 // The remembered set for this region. 224 // (Might want to make this "inline" later, to avoid some alloc failure 225 // issues.) 226 HeapRegionRemSet* _rem_set; 227 228 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 229 230 // Auxiliary functions for scan_and_forward support. 231 // See comments for CompactibleSpace for more information. 232 inline HeapWord* scan_limit() const { 233 return top(); 234 } 235 236 inline bool scanned_block_is_obj(const HeapWord* addr) const { 237 return true; // Always true, since scan_limit is top 238 } 239 240 inline size_t scanned_block_size(const HeapWord* addr) const { 241 return HeapRegion::block_size(addr); // Avoid virtual call 242 } 243 244 protected: 245 // The index of this region in the heap region sequence. 246 uint _hrm_index; 247 248 AllocationContext_t _allocation_context; 249 250 HeapRegionType _type; 251 252 // For a humongous region, region in which it starts. 253 HeapRegion* _humongous_start_region; 254 255 // True iff an attempt to evacuate an object in the region failed. 256 bool _evacuation_failed; 257 258 // A heap region may be a member one of a number of special subsets, each 259 // represented as linked lists through the field below. Currently, there 260 // is only one set: 261 // The collection set. 262 HeapRegion* _next_in_special_set; 263 264 // next region in the young "generation" region set 265 HeapRegion* _next_young_region; 266 267 // Next region whose cards need cleaning 268 HeapRegion* _next_dirty_cards_region; 269 270 // Fields used by the HeapRegionSetBase class and subclasses. 271 HeapRegion* _next; 272 HeapRegion* _prev; 273 #ifdef ASSERT 274 HeapRegionSetBase* _containing_set; 275 #endif // ASSERT 276 277 // We use concurrent marking to determine the amount of live data 278 // in each heap region. 279 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 280 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 281 282 // The calculated GC efficiency of the region. 283 double _gc_efficiency; 284 285 int _young_index_in_cset; 286 SurvRateGroup* _surv_rate_group; 287 int _age_index; 288 289 // The start of the unmarked area. The unmarked area extends from this 290 // word until the top and/or end of the region, and is the part 291 // of the region for which no marking was done, i.e. objects may 292 // have been allocated in this part since the last mark phase. 293 // "prev" is the top at the start of the last completed marking. 294 // "next" is the top at the start of the in-progress marking (if any.) 295 HeapWord* _prev_top_at_mark_start; 296 HeapWord* _next_top_at_mark_start; 297 // If a collection pause is in progress, this is the top at the start 298 // of that pause. 299 300 void init_top_at_mark_start() { 301 assert(_prev_marked_bytes == 0 && 302 _next_marked_bytes == 0, 303 "Must be called after zero_marked_bytes."); 304 HeapWord* bot = bottom(); 305 _prev_top_at_mark_start = bot; 306 _next_top_at_mark_start = bot; 307 } 308 309 // Cached attributes used in the collection set policy information 310 311 // The RSet length that was added to the total value 312 // for the collection set. 313 size_t _recorded_rs_length; 314 315 // The predicted elapsed time that was added to total value 316 // for the collection set. 317 double _predicted_elapsed_time_ms; 318 319 // The predicted number of bytes to copy that was added to 320 // the total value for the collection set. 321 size_t _predicted_bytes_to_copy; 322 323 public: 324 HeapRegion(uint hrm_index, 325 G1BlockOffsetSharedArray* sharedOffsetArray, 326 MemRegion mr); 327 328 // Initializing the HeapRegion not only resets the data structure, but also 329 // resets the BOT for that heap region. 330 // The default values for clear_space means that we will do the clearing if 331 // there's clearing to be done ourselves. We also always mangle the space. 332 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 333 334 static int LogOfHRGrainBytes; 335 static int LogOfHRGrainWords; 336 337 static size_t GrainBytes; 338 static size_t GrainWords; 339 static size_t CardsPerRegion; 340 341 static size_t align_up_to_region_byte_size(size_t sz) { 342 return (sz + (size_t) GrainBytes - 1) & 343 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 344 } 345 346 static size_t max_region_size(); 347 static size_t min_region_size_in_words(); 348 349 // It sets up the heap region size (GrainBytes / GrainWords), as 350 // well as other related fields that are based on the heap region 351 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 352 // CardsPerRegion). All those fields are considered constant 353 // throughout the JVM's execution, therefore they should only be set 354 // up once during initialization time. 355 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); 356 357 // All allocated blocks are occupied by objects in a HeapRegion 358 bool block_is_obj(const HeapWord* p) const; 359 360 // Returns the object size for all valid block starts 361 // and the amount of unallocated words if called on top() 362 size_t block_size(const HeapWord* p) const; 363 364 // Override for scan_and_forward support. 365 void prepare_for_compaction(CompactPoint* cp); 366 367 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size); 368 inline HeapWord* allocate_no_bot_updates(size_t word_size); 369 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size); 370 371 // If this region is a member of a HeapRegionManager, the index in that 372 // sequence, otherwise -1. 373 uint hrm_index() const { return _hrm_index; } 374 375 // The number of bytes marked live in the region in the last marking phase. 376 size_t marked_bytes() { return _prev_marked_bytes; } 377 size_t live_bytes() { 378 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 379 } 380 381 // The number of bytes counted in the next marking. 382 size_t next_marked_bytes() { return _next_marked_bytes; } 383 // The number of bytes live wrt the next marking. 384 size_t next_live_bytes() { 385 return 386 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 387 } 388 389 // A lower bound on the amount of garbage bytes in the region. 390 size_t garbage_bytes() { 391 size_t used_at_mark_start_bytes = 392 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 393 assert(used_at_mark_start_bytes >= marked_bytes(), 394 "Can't mark more than we have."); 395 return used_at_mark_start_bytes - marked_bytes(); 396 } 397 398 // Return the amount of bytes we'll reclaim if we collect this 399 // region. This includes not only the known garbage bytes in the 400 // region but also any unallocated space in it, i.e., [top, end), 401 // since it will also be reclaimed if we collect the region. 402 size_t reclaimable_bytes() { 403 size_t known_live_bytes = live_bytes(); 404 assert(known_live_bytes <= capacity(), "sanity"); 405 return capacity() - known_live_bytes; 406 } 407 408 // An upper bound on the number of live bytes in the region. 409 size_t max_live_bytes() { return used() - garbage_bytes(); } 410 411 void add_to_marked_bytes(size_t incr_bytes) { 412 _next_marked_bytes = _next_marked_bytes + incr_bytes; 413 assert(_next_marked_bytes <= used(), "invariant" ); 414 } 415 416 void zero_marked_bytes() { 417 _prev_marked_bytes = _next_marked_bytes = 0; 418 } 419 420 const char* get_type_str() const { return _type.get_str(); } 421 const char* get_short_type_str() const { return _type.get_short_str(); } 422 423 bool is_free() const { return _type.is_free(); } 424 425 bool is_young() const { return _type.is_young(); } 426 bool is_eden() const { return _type.is_eden(); } 427 bool is_survivor() const { return _type.is_survivor(); } 428 429 bool is_humongous() const { return _type.is_humongous(); } 430 bool is_starts_humongous() const { return _type.is_starts_humongous(); } 431 bool is_continues_humongous() const { return _type.is_continues_humongous(); } 432 433 bool is_old() const { return _type.is_old(); } 434 435 // A pinned region contains objects which are not moved by garbage collections. 436 // Humongous regions and archive regions are pinned. 437 bool is_pinned() const { return _type.is_pinned(); } 438 439 // An archive region is a pinned region, also tagged as old, which 440 // should not be marked during mark/sweep. This allows the address 441 // space to be shared by JVM instances. 442 bool is_archive() const { return _type.is_archive(); } 443 444 // For a humongous region, region in which it starts. 445 HeapRegion* humongous_start_region() const { 446 return _humongous_start_region; 447 } 448 449 // Return the number of distinct regions that are covered by this region: 450 // 1 if the region is not humongous, >= 1 if the region is humongous. 451 uint region_num() const { 452 if (!is_humongous()) { 453 return 1U; 454 } else { 455 assert(is_starts_humongous(), "doesn't make sense on HC regions"); 456 assert(capacity() % HeapRegion::GrainBytes == 0, "sanity"); 457 return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes); 458 } 459 } 460 461 // Return the index + 1 of the last HC regions that's associated 462 // with this HS region. 463 uint last_hc_index() const { 464 assert(is_starts_humongous(), "don't call this otherwise"); 465 return hrm_index() + region_num(); 466 } 467 468 // Same as Space::is_in_reserved, but will use the original size of the region. 469 // The original size is different only for start humongous regions. They get 470 // their _end set up to be the end of the last continues region of the 471 // corresponding humongous object. 472 bool is_in_reserved_raw(const void* p) const { 473 return _bottom <= p && p < orig_end(); 474 } 475 476 // Makes the current region be a "starts humongous" region, i.e., 477 // the first region in a series of one or more contiguous regions 478 // that will contain a single "humongous" object. The two parameters 479 // are as follows: 480 // 481 // new_top : The new value of the top field of this region which 482 // points to the end of the humongous object that's being 483 // allocated. If there is more than one region in the series, top 484 // will lie beyond this region's original end field and on the last 485 // region in the series. 486 // 487 // new_end : The new value of the end field of this region which 488 // points to the end of the last region in the series. If there is 489 // one region in the series (namely: this one) end will be the same 490 // as the original end of this region. 491 // 492 // Updating top and end as described above makes this region look as 493 // if it spans the entire space taken up by all the regions in the 494 // series and an single allocation moved its top to new_top. This 495 // ensures that the space (capacity / allocated) taken up by all 496 // humongous regions can be calculated by just looking at the 497 // "starts humongous" regions and by ignoring the "continues 498 // humongous" regions. 499 void set_starts_humongous(HeapWord* new_top, HeapWord* new_end); 500 501 // Makes the current region be a "continues humongous' 502 // region. first_hr is the "start humongous" region of the series 503 // which this region will be part of. 504 void set_continues_humongous(HeapRegion* first_hr); 505 506 // Unsets the humongous-related fields on the region. 507 void clear_humongous(); 508 509 // If the region has a remembered set, return a pointer to it. 510 HeapRegionRemSet* rem_set() const { 511 return _rem_set; 512 } 513 514 inline bool in_collection_set() const; 515 516 inline HeapRegion* next_in_collection_set() const; 517 inline void set_next_in_collection_set(HeapRegion* r); 518 519 void set_allocation_context(AllocationContext_t context) { 520 _allocation_context = context; 521 } 522 523 AllocationContext_t allocation_context() const { 524 return _allocation_context; 525 } 526 527 // Methods used by the HeapRegionSetBase class and subclasses. 528 529 // Getter and setter for the next and prev fields used to link regions into 530 // linked lists. 531 HeapRegion* next() { return _next; } 532 HeapRegion* prev() { return _prev; } 533 534 void set_next(HeapRegion* next) { _next = next; } 535 void set_prev(HeapRegion* prev) { _prev = prev; } 536 537 // Every region added to a set is tagged with a reference to that 538 // set. This is used for doing consistency checking to make sure that 539 // the contents of a set are as they should be and it's only 540 // available in non-product builds. 541 #ifdef ASSERT 542 void set_containing_set(HeapRegionSetBase* containing_set) { 543 assert((containing_set == NULL && _containing_set != NULL) || 544 (containing_set != NULL && _containing_set == NULL), 545 "containing_set: " PTR_FORMAT " " 546 "_containing_set: " PTR_FORMAT, 547 p2i(containing_set), p2i(_containing_set)); 548 549 _containing_set = containing_set; 550 } 551 552 HeapRegionSetBase* containing_set() { return _containing_set; } 553 #else // ASSERT 554 void set_containing_set(HeapRegionSetBase* containing_set) { } 555 556 // containing_set() is only used in asserts so there's no reason 557 // to provide a dummy version of it. 558 #endif // ASSERT 559 560 HeapRegion* get_next_young_region() { return _next_young_region; } 561 void set_next_young_region(HeapRegion* hr) { 562 _next_young_region = hr; 563 } 564 565 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 566 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 567 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 568 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 569 570 // For the start region of a humongous sequence, it's original end(). 571 HeapWord* orig_end() const { return _bottom + GrainWords; } 572 573 // Reset HR stuff to default values. 574 void hr_clear(bool par, bool clear_space, bool locked = false); 575 void par_clear(); 576 577 // Get the start of the unmarked area in this region. 578 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 579 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 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 // Notify the region that concurrent marking is starting. Initialize 586 // all fields related to the next marking info. 587 inline void note_start_of_marking(); 588 589 // Notify the region that concurrent marking has finished. Copy the 590 // (now finalized) next marking info fields into the prev marking 591 // info fields. 592 inline void note_end_of_marking(); 593 594 // Notify the region that it will be used as to-space during a GC 595 // and we are about to start copying objects into it. 596 inline void note_start_of_copying(bool during_initial_mark); 597 598 // Notify the region that it ceases being to-space during a GC and 599 // we will not copy objects into it any more. 600 inline void note_end_of_copying(bool during_initial_mark); 601 602 // Notify the region that we are about to start processing 603 // self-forwarded objects during evac failure handling. 604 void note_self_forwarding_removal_start(bool during_initial_mark, 605 bool during_conc_mark); 606 607 // Notify the region that we have finished processing self-forwarded 608 // objects during evac failure handling. 609 void note_self_forwarding_removal_end(bool during_initial_mark, 610 bool during_conc_mark, 611 size_t marked_bytes); 612 613 // Returns "false" iff no object in the region was allocated when the 614 // last mark phase ended. 615 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 616 617 void reset_during_compaction() { 618 assert(is_starts_humongous(), 619 "should only be called for starts humongous regions"); 620 621 zero_marked_bytes(); 622 init_top_at_mark_start(); 623 } 624 625 void calc_gc_efficiency(void); 626 double gc_efficiency() { return _gc_efficiency;} 627 628 int young_index_in_cset() const { return _young_index_in_cset; } 629 void set_young_index_in_cset(int index) { 630 assert( (index == -1) || is_young(), "pre-condition" ); 631 _young_index_in_cset = index; 632 } 633 634 int age_in_surv_rate_group() { 635 assert( _surv_rate_group != NULL, "pre-condition" ); 636 assert( _age_index > -1, "pre-condition" ); 637 return _surv_rate_group->age_in_group(_age_index); 638 } 639 640 void record_surv_words_in_group(size_t words_survived) { 641 assert( _surv_rate_group != NULL, "pre-condition" ); 642 assert( _age_index > -1, "pre-condition" ); 643 int age_in_group = age_in_surv_rate_group(); 644 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 645 } 646 647 int age_in_surv_rate_group_cond() { 648 if (_surv_rate_group != NULL) 649 return age_in_surv_rate_group(); 650 else 651 return -1; 652 } 653 654 SurvRateGroup* surv_rate_group() { 655 return _surv_rate_group; 656 } 657 658 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 659 assert( surv_rate_group != NULL, "pre-condition" ); 660 assert( _surv_rate_group == NULL, "pre-condition" ); 661 assert( is_young(), "pre-condition" ); 662 663 _surv_rate_group = surv_rate_group; 664 _age_index = surv_rate_group->next_age_index(); 665 } 666 667 void uninstall_surv_rate_group() { 668 if (_surv_rate_group != NULL) { 669 assert( _age_index > -1, "pre-condition" ); 670 assert( is_young(), "pre-condition" ); 671 672 _surv_rate_group = NULL; 673 _age_index = -1; 674 } else { 675 assert( _age_index == -1, "pre-condition" ); 676 } 677 } 678 679 void set_free() { _type.set_free(); } 680 681 void set_eden() { _type.set_eden(); } 682 void set_eden_pre_gc() { _type.set_eden_pre_gc(); } 683 void set_survivor() { _type.set_survivor(); } 684 685 void set_old() { _type.set_old(); } 686 687 void set_archive() { _type.set_archive(); } 688 689 // Determine if an object has been allocated since the last 690 // mark performed by the collector. This returns true iff the object 691 // is within the unmarked area of the region. 692 bool obj_allocated_since_prev_marking(oop obj) const { 693 return (HeapWord *) obj >= prev_top_at_mark_start(); 694 } 695 bool obj_allocated_since_next_marking(oop obj) const { 696 return (HeapWord *) obj >= next_top_at_mark_start(); 697 } 698 699 // Returns the "evacuation_failed" property of the region. 700 bool evacuation_failed() { return _evacuation_failed; } 701 702 // Sets the "evacuation_failed" property of the region. 703 void set_evacuation_failed(bool b) { 704 _evacuation_failed = b; 705 706 if (b) { 707 _next_marked_bytes = 0; 708 } 709 } 710 711 // Requires that "mr" be entirely within the region. 712 // Apply "cl->do_object" to all objects that intersect with "mr". 713 // If the iteration encounters an unparseable portion of the region, 714 // or if "cl->abort()" is true after a closure application, 715 // terminate the iteration and return the address of the start of the 716 // subregion that isn't done. (The two can be distinguished by querying 717 // "cl->abort()".) Return of "NULL" indicates that the iteration 718 // completed. 719 HeapWord* 720 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 721 722 // filter_young: if true and the region is a young region then we 723 // skip the iteration. 724 // card_ptr: if not NULL, and we decide that the card is not young 725 // and we iterate over it, we'll clean the card before we start the 726 // iteration. 727 HeapWord* 728 oops_on_card_seq_iterate_careful(MemRegion mr, 729 FilterOutOfRegionClosure* cl, 730 bool filter_young, 731 jbyte* card_ptr); 732 733 size_t recorded_rs_length() const { return _recorded_rs_length; } 734 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 735 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 736 737 void set_recorded_rs_length(size_t rs_length) { 738 _recorded_rs_length = rs_length; 739 } 740 741 void set_predicted_elapsed_time_ms(double ms) { 742 _predicted_elapsed_time_ms = ms; 743 } 744 745 void set_predicted_bytes_to_copy(size_t bytes) { 746 _predicted_bytes_to_copy = bytes; 747 } 748 749 virtual CompactibleSpace* next_compaction_space() const; 750 751 virtual void reset_after_compaction(); 752 753 // Routines for managing a list of code roots (attached to the 754 // this region's RSet) that point into this heap region. 755 void add_strong_code_root(nmethod* nm); 756 void add_strong_code_root_locked(nmethod* nm); 757 void remove_strong_code_root(nmethod* nm); 758 759 // Applies blk->do_code_blob() to each of the entries in 760 // the strong code roots list for this region 761 void strong_code_roots_do(CodeBlobClosure* blk) const; 762 763 // Verify that the entries on the strong code root list for this 764 // region are live and include at least one pointer into this region. 765 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 766 767 void print() const; 768 void print_on(outputStream* st) const; 769 770 // vo == UsePrevMarking -> use "prev" marking information, 771 // vo == UseNextMarking -> use "next" marking information 772 // vo == UseMarkWord -> use the mark word in the object header 773 // 774 // NOTE: Only the "prev" marking information is guaranteed to be 775 // consistent most of the time, so most calls to this should use 776 // vo == UsePrevMarking. 777 // Currently, there is only one case where this is called with 778 // vo == UseNextMarking, which is to verify the "next" marking 779 // information at the end of remark. 780 // Currently there is only one place where this is called with 781 // vo == UseMarkWord, which is to verify the marking during a 782 // full GC. 783 void verify(VerifyOption vo, bool *failures) const; 784 785 // Override; it uses the "prev" marking information 786 virtual void verify() const; 787 }; 788 789 // HeapRegionClosure is used for iterating over regions. 790 // Terminates the iteration when the "doHeapRegion" method returns "true". 791 class HeapRegionClosure : public StackObj { 792 friend class HeapRegionManager; 793 friend class G1CollectedHeap; 794 795 bool _complete; 796 void incomplete() { _complete = false; } 797 798 public: 799 HeapRegionClosure(): _complete(true) {} 800 801 // Typically called on each region until it returns true. 802 virtual bool doHeapRegion(HeapRegion* r) = 0; 803 804 // True after iteration if the closure was applied to all heap regions 805 // and returned "false" in all cases. 806 bool complete() { return _complete; } 807 }; 808 809 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP