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 "utilities/macros.hpp" 35 36 // A HeapRegion is the smallest piece of a G1CollectedHeap that 37 // can be collected independently. 38 39 // NOTE: Although a HeapRegion is a Space, its 40 // Space::initDirtyCardClosure method must not be called. 41 // The problem is that the existence of this method breaks 42 // the independence of barrier sets from remembered sets. 43 // The solution is to remove this method from the definition 44 // of a Space. 45 46 // Each heap region is self contained. top() and end() can never 47 // be set beyond the end of the region. For humongous objects, 48 // the first region is a StartsHumongous region. If the humongous 49 // object is larger than a heap region, the following regions will 50 // be of type ContinuesHumongous. In this case the top() of the 51 // StartHumongous region and all ContinuesHumongous regions except 52 // the last will point to their own end. For the last ContinuesHumongous 53 // region, top() will equal the object's top. 54 55 class G1CollectedHeap; 56 class HeapRegionRemSet; 57 class HeapRegionRemSetIterator; 58 class HeapRegion; 59 class HeapRegionSetBase; 60 class nmethod; 61 62 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]" 63 #define HR_FORMAT_PARAMS(_hr_) \ 64 (_hr_)->hrm_index(), \ 65 (_hr_)->get_short_type_str(), \ 66 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 67 68 // sentinel value for hrm_index 69 #define G1_NO_HRM_INDEX ((uint) -1) 70 71 // A dirty card to oop closure for heap regions. It 72 // knows how to get the G1 heap and how to use the bitmap 73 // in the concurrent marker used by G1 to filter remembered 74 // sets. 75 76 class HeapRegionDCTOC : public DirtyCardToOopClosure { 77 private: 78 HeapRegion* _hr; 79 G1ParPushHeapRSClosure* _rs_scan; 80 G1CollectedHeap* _g1; 81 82 // Walk the given memory region from bottom to (actual) top 83 // looking for objects and applying the oop closure (_cl) to 84 // them. The base implementation of this treats the area as 85 // blocks, where a block may or may not be an object. Sub- 86 // classes should override this to provide more accurate 87 // or possibly more efficient walking. 88 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); 89 90 public: 91 HeapRegionDCTOC(G1CollectedHeap* g1, 92 HeapRegion* hr, 93 G1ParPushHeapRSClosure* cl, 94 CardTableModRefBS::PrecisionStyle precision); 95 }; 96 97 // The complicating factor is that BlockOffsetTable diverged 98 // significantly, and we need functionality that is only in the G1 version. 99 // So I copied that code, which led to an alternate G1 version of 100 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 101 // be reconciled, then G1OffsetTableContigSpace could go away. 102 103 // The idea behind time stamps is the following. We want to keep track of 104 // the highest address where it's safe to scan objects for each region. 105 // This is only relevant for current GC alloc regions so we keep a time stamp 106 // per region to determine if the region has been allocated during the current 107 // GC or not. If the time stamp is current we report a scan_top value which 108 // was saved at the end of the previous GC for retained alloc regions and which is 109 // equal to the bottom for all other regions. 110 // There is a race between card scanners and allocating gc workers where we must ensure 111 // that card scanners do not read the memory allocated by the gc workers. 112 // In order to enforce that, we must not return a value of _top which is more recent than the 113 // time stamp. This is due to the fact that a region may become a gc alloc region at 114 // some point after we've read the timestamp value as being < the current time stamp. 115 // The time stamps are re-initialized to zero at cleanup and at Full GCs. 116 // The current scheme that uses sequential unsigned ints will fail only if we have 4b 117 // evacuation pauses between two cleanups, which is _highly_ unlikely. 118 class G1OffsetTableContigSpace: public CompactibleSpace { 119 friend class VMStructs; 120 HeapWord* volatile _top; 121 HeapWord* volatile _scan_top; 122 protected: 123 G1BlockOffsetArrayContigSpace _offsets; 124 Mutex _par_alloc_lock; 125 volatile unsigned _gc_time_stamp; 126 // When we need to retire an allocation region, while other threads 127 // are also concurrently trying to allocate into it, we typically 128 // allocate a dummy object at the end of the region to ensure that 129 // no more allocations can take place in it. However, sometimes we 130 // want to know where the end of the last "real" object we allocated 131 // into the region was and this is what this keeps track. 132 HeapWord* _pre_dummy_top; 133 134 public: 135 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 136 MemRegion mr); 137 138 void set_top(HeapWord* value) { _top = value; } 139 HeapWord* top() const { return _top; } 140 141 protected: 142 // Reset the G1OffsetTableContigSpace. 143 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 144 145 HeapWord* volatile* top_addr() { return &_top; } 146 // Try to allocate at least min_word_size and up to desired_size from this Space. 147 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 148 // space allocated. 149 // This version assumes that all allocation requests to this Space are properly 150 // synchronized. 151 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 152 // Try to allocate at least min_word_size and up to desired_size from this Space. 153 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 154 // space allocated. 155 // This version synchronizes with other calls to par_allocate_impl(). 156 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 157 158 public: 159 void reset_after_compaction() { set_top(compaction_top()); } 160 161 size_t used() const { return byte_size(bottom(), top()); } 162 size_t free() const { return byte_size(top(), end()); } 163 bool is_free_block(const HeapWord* p) const { return p >= top(); } 164 165 MemRegion used_region() const { return MemRegion(bottom(), top()); } 166 167 void object_iterate(ObjectClosure* blk); 168 void safe_object_iterate(ObjectClosure* blk); 169 170 void set_bottom(HeapWord* value); 171 void set_end(HeapWord* value); 172 173 void mangle_unused_area() PRODUCT_RETURN; 174 void mangle_unused_area_complete() PRODUCT_RETURN; 175 176 HeapWord* scan_top() const; 177 void record_timestamp(); 178 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 179 unsigned get_gc_time_stamp() { return _gc_time_stamp; } 180 void record_retained_region(); 181 182 // See the comment above in the declaration of _pre_dummy_top for an 183 // explanation of what it is. 184 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 185 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 186 _pre_dummy_top = pre_dummy_top; 187 } 188 HeapWord* pre_dummy_top() { 189 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 190 } 191 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 192 193 virtual void clear(bool mangle_space); 194 195 HeapWord* block_start(const void* p); 196 HeapWord* block_start_const(const void* p) const; 197 198 // Allocation (return NULL if full). Assumes the caller has established 199 // mutually exclusive access to the space. 200 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 201 // Allocation (return NULL if full). Enforces mutual exclusion internally. 202 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 203 204 virtual HeapWord* allocate(size_t word_size); 205 virtual HeapWord* par_allocate(size_t word_size); 206 207 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; } 208 209 // MarkSweep support phase3 210 virtual HeapWord* initialize_threshold(); 211 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 212 213 virtual void print() const; 214 215 void reset_bot() { 216 _offsets.reset_bot(); 217 } 218 219 void print_bot_on(outputStream* out) { 220 _offsets.print_on(out); 221 } 222 }; 223 224 class HeapRegion: public G1OffsetTableContigSpace { 225 friend class VMStructs; 226 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class 227 template <typename SpaceType> 228 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp); 229 private: 230 231 // The remembered set for this region. 232 // (Might want to make this "inline" later, to avoid some alloc failure 233 // issues.) 234 HeapRegionRemSet* _rem_set; 235 236 G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; } 237 238 // Auxiliary functions for scan_and_forward support. 239 // See comments for CompactibleSpace for more information. 240 inline HeapWord* scan_limit() const { 241 return top(); 242 } 243 244 inline bool scanned_block_is_obj(const HeapWord* addr) const { 245 return true; // Always true, since scan_limit is top 246 } 247 248 inline size_t scanned_block_size(const HeapWord* addr) const { 249 return HeapRegion::block_size(addr); // Avoid virtual call 250 } 251 252 protected: 253 // The index of this region in the heap region sequence. 254 uint _hrm_index; 255 256 AllocationContext_t _allocation_context; 257 258 HeapRegionType _type; 259 260 // For a humongous region, region in which it starts. 261 HeapRegion* _humongous_start_region; 262 263 // True iff an attempt to evacuate an object in the region failed. 264 bool _evacuation_failed; 265 266 // A heap region may be a member one of a number of special subsets, each 267 // represented as linked lists through the field below. Currently, there 268 // is only one set: 269 // The collection set. 270 HeapRegion* _next_in_special_set; 271 272 // next region in the young "generation" region set 273 HeapRegion* _next_young_region; 274 275 // Next region whose cards need cleaning 276 HeapRegion* _next_dirty_cards_region; 277 278 // Fields used by the HeapRegionSetBase class and subclasses. 279 HeapRegion* _next; 280 HeapRegion* _prev; 281 #ifdef ASSERT 282 HeapRegionSetBase* _containing_set; 283 #endif // ASSERT 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 // The calculated GC efficiency of the region. 291 double _gc_efficiency; 292 293 int _young_index_in_cset; 294 SurvRateGroup* _surv_rate_group; 295 int _age_index; 296 297 // The start of the unmarked area. The unmarked area extends from this 298 // word until the top and/or end of the region, and is the part 299 // of the region for which no marking was done, i.e. objects may 300 // have been allocated in this part since the last mark phase. 301 // "prev" is the top at the start of the last completed marking. 302 // "next" is the top at the start of the in-progress marking (if any.) 303 HeapWord* _prev_top_at_mark_start; 304 HeapWord* _next_top_at_mark_start; 305 // If a collection pause is in progress, this is the top at the start 306 // of that pause. 307 308 void init_top_at_mark_start() { 309 assert(_prev_marked_bytes == 0 && 310 _next_marked_bytes == 0, 311 "Must be called after zero_marked_bytes."); 312 HeapWord* bot = bottom(); 313 _prev_top_at_mark_start = bot; 314 _next_top_at_mark_start = bot; 315 } 316 317 // Cached attributes used in the collection set policy information 318 319 // The RSet length that was added to the total value 320 // for the collection set. 321 size_t _recorded_rs_length; 322 323 // The predicted elapsed time that was added to total value 324 // for the collection set. 325 double _predicted_elapsed_time_ms; 326 327 // The predicted number of bytes to copy that was added to 328 // the total value for the collection set. 329 size_t _predicted_bytes_to_copy; 330 331 public: 332 HeapRegion(uint hrm_index, 333 G1BlockOffsetSharedArray* sharedOffsetArray, 334 MemRegion mr); 335 336 // Initializing the HeapRegion not only resets the data structure, but also 337 // resets the BOT for that heap region. 338 // The default values for clear_space means that we will do the clearing if 339 // there's clearing to be done ourselves. We also always mangle the space. 340 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 341 342 static int LogOfHRGrainBytes; 343 static int LogOfHRGrainWords; 344 345 static size_t GrainBytes; 346 static size_t GrainWords; 347 static size_t CardsPerRegion; 348 349 static size_t align_up_to_region_byte_size(size_t sz) { 350 return (sz + (size_t) GrainBytes - 1) & 351 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 352 } 353 354 static size_t max_region_size(); 355 static size_t min_region_size_in_words(); 356 357 // It sets up the heap region size (GrainBytes / GrainWords), as 358 // well as other related fields that are based on the heap region 359 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 360 // CardsPerRegion). All those fields are considered constant 361 // throughout the JVM's execution, therefore they should only be set 362 // up once during initialization time. 363 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); 364 365 // All allocated blocks are occupied by objects in a HeapRegion 366 bool block_is_obj(const HeapWord* p) const; 367 368 // Returns the object size for all valid block starts 369 // and the amount of unallocated words if called on top() 370 size_t block_size(const HeapWord* p) const; 371 372 // Override for scan_and_forward support. 373 void prepare_for_compaction(CompactPoint* cp); 374 375 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size); 376 inline HeapWord* allocate_no_bot_updates(size_t word_size); 377 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size); 378 379 // If this region is a member of a HeapRegionManager, the index in that 380 // sequence, otherwise -1. 381 uint hrm_index() const { return _hrm_index; } 382 383 // The number of bytes marked live in the region in the last marking phase. 384 size_t marked_bytes() { return _prev_marked_bytes; } 385 size_t live_bytes() { 386 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 387 } 388 389 // The number of bytes counted in the next marking. 390 size_t next_marked_bytes() { return _next_marked_bytes; } 391 // The number of bytes live wrt the next marking. 392 size_t next_live_bytes() { 393 return 394 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 395 } 396 397 // A lower bound on the amount of garbage bytes in the region. 398 size_t garbage_bytes() { 399 size_t used_at_mark_start_bytes = 400 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 401 return used_at_mark_start_bytes - marked_bytes(); 402 } 403 404 // Return the amount of bytes we'll reclaim if we collect this 405 // region. This includes not only the known garbage bytes in the 406 // region but also any unallocated space in it, i.e., [top, end), 407 // since it will also be reclaimed if we collect the region. 408 size_t reclaimable_bytes() { 409 size_t known_live_bytes = live_bytes(); 410 assert(known_live_bytes <= capacity(), "sanity"); 411 return capacity() - known_live_bytes; 412 } 413 414 // An upper bound on the number of live bytes in the region. 415 size_t max_live_bytes() { return used() - garbage_bytes(); } 416 417 void add_to_marked_bytes(size_t incr_bytes) { 418 _next_marked_bytes = _next_marked_bytes + incr_bytes; 419 } 420 421 void zero_marked_bytes() { 422 _prev_marked_bytes = _next_marked_bytes = 0; 423 } 424 425 const char* get_type_str() const { return _type.get_str(); } 426 const char* get_short_type_str() const { return _type.get_short_str(); } 427 428 bool is_free() const { return _type.is_free(); } 429 430 bool is_young() const { return _type.is_young(); } 431 bool is_eden() const { return _type.is_eden(); } 432 bool is_survivor() const { return _type.is_survivor(); } 433 434 bool is_humongous() const { return _type.is_humongous(); } 435 bool is_starts_humongous() const { return _type.is_starts_humongous(); } 436 bool is_continues_humongous() const { return _type.is_continues_humongous(); } 437 438 bool is_old() const { return _type.is_old(); } 439 440 // A pinned region contains objects which are not moved by garbage collections. 441 // Humongous regions and archive regions are pinned. 442 bool is_pinned() const { return _type.is_pinned(); } 443 444 // An archive region is a pinned region, also tagged as old, which 445 // should not be marked during mark/sweep. This allows the address 446 // space to be shared by JVM instances. 447 bool is_archive() const { return _type.is_archive(); } 448 449 // For a humongous region, region in which it starts. 450 HeapRegion* humongous_start_region() const { 451 return _humongous_start_region; 452 } 453 454 // Makes the current region be a "starts humongous" region, i.e., 455 // the first region in a series of one or more contiguous regions 456 // that will contain a single "humongous" object. 457 // 458 // obj_top : points to the end of the humongous object that's being 459 // allocated. 460 void set_starts_humongous(HeapWord* obj_top); 461 462 // Makes the current region be a "continues humongous' 463 // region. first_hr is the "start humongous" region of the series 464 // which this region will be part of. 465 void set_continues_humongous(HeapRegion* first_hr); 466 467 // Unsets the humongous-related fields on the region. 468 void clear_humongous(); 469 470 // If the region has a remembered set, return a pointer to it. 471 HeapRegionRemSet* rem_set() const { 472 return _rem_set; 473 } 474 475 inline bool in_collection_set() const; 476 477 inline HeapRegion* next_in_collection_set() const; 478 inline void set_next_in_collection_set(HeapRegion* r); 479 480 void set_allocation_context(AllocationContext_t context) { 481 _allocation_context = context; 482 } 483 484 AllocationContext_t allocation_context() const { 485 return _allocation_context; 486 } 487 488 // Methods used by the HeapRegionSetBase class and subclasses. 489 490 // Getter and setter for the next and prev fields used to link regions into 491 // linked lists. 492 HeapRegion* next() { return _next; } 493 HeapRegion* prev() { return _prev; } 494 495 void set_next(HeapRegion* next) { _next = next; } 496 void set_prev(HeapRegion* prev) { _prev = prev; } 497 498 // Every region added to a set is tagged with a reference to that 499 // set. This is used for doing consistency checking to make sure that 500 // the contents of a set are as they should be and it's only 501 // available in non-product builds. 502 #ifdef ASSERT 503 void set_containing_set(HeapRegionSetBase* containing_set) { 504 assert((containing_set == NULL && _containing_set != NULL) || 505 (containing_set != NULL && _containing_set == NULL), 506 "containing_set: " PTR_FORMAT " " 507 "_containing_set: " PTR_FORMAT, 508 p2i(containing_set), p2i(_containing_set)); 509 510 _containing_set = containing_set; 511 } 512 513 HeapRegionSetBase* containing_set() { return _containing_set; } 514 #else // ASSERT 515 void set_containing_set(HeapRegionSetBase* containing_set) { } 516 517 // containing_set() is only used in asserts so there's no reason 518 // to provide a dummy version of it. 519 #endif // ASSERT 520 521 HeapRegion* get_next_young_region() { return _next_young_region; } 522 void set_next_young_region(HeapRegion* hr) { 523 _next_young_region = hr; 524 } 525 526 HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; } 527 HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; } 528 void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; } 529 bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; } 530 531 // Reset HR stuff to default values. 532 void hr_clear(bool par, bool clear_space, bool locked = false); 533 void par_clear(); 534 535 // Get the start of the unmarked area in this region. 536 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 537 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 538 539 // Note the start or end of marking. This tells the heap region 540 // that the collector is about to start or has finished (concurrently) 541 // marking the heap. 542 543 // Notify the region that concurrent marking is starting. Initialize 544 // all fields related to the next marking info. 545 inline void note_start_of_marking(); 546 547 // Notify the region that concurrent marking has finished. Copy the 548 // (now finalized) next marking info fields into the prev marking 549 // info fields. 550 inline void note_end_of_marking(); 551 552 // Notify the region that it will be used as to-space during a GC 553 // and we are about to start copying objects into it. 554 inline void note_start_of_copying(bool during_initial_mark); 555 556 // Notify the region that it ceases being to-space during a GC and 557 // we will not copy objects into it any more. 558 inline void note_end_of_copying(bool during_initial_mark); 559 560 // Notify the region that we are about to start processing 561 // self-forwarded objects during evac failure handling. 562 void note_self_forwarding_removal_start(bool during_initial_mark, 563 bool during_conc_mark); 564 565 // Notify the region that we have finished processing self-forwarded 566 // objects during evac failure handling. 567 void note_self_forwarding_removal_end(bool during_initial_mark, 568 bool during_conc_mark, 569 size_t marked_bytes); 570 571 // Returns "false" iff no object in the region was allocated when the 572 // last mark phase ended. 573 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 574 575 void reset_during_compaction() { 576 assert(is_humongous(), 577 "should only be called for humongous regions"); 578 579 zero_marked_bytes(); 580 init_top_at_mark_start(); 581 } 582 583 void calc_gc_efficiency(void); 584 double gc_efficiency() { return _gc_efficiency;} 585 586 int young_index_in_cset() const { return _young_index_in_cset; } 587 void set_young_index_in_cset(int index) { 588 assert( (index == -1) || is_young(), "pre-condition" ); 589 _young_index_in_cset = index; 590 } 591 592 int age_in_surv_rate_group() { 593 assert( _surv_rate_group != NULL, "pre-condition" ); 594 assert( _age_index > -1, "pre-condition" ); 595 return _surv_rate_group->age_in_group(_age_index); 596 } 597 598 void record_surv_words_in_group(size_t words_survived) { 599 assert( _surv_rate_group != NULL, "pre-condition" ); 600 assert( _age_index > -1, "pre-condition" ); 601 int age_in_group = age_in_surv_rate_group(); 602 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 603 } 604 605 int age_in_surv_rate_group_cond() { 606 if (_surv_rate_group != NULL) 607 return age_in_surv_rate_group(); 608 else 609 return -1; 610 } 611 612 SurvRateGroup* surv_rate_group() { 613 return _surv_rate_group; 614 } 615 616 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 617 assert( surv_rate_group != NULL, "pre-condition" ); 618 assert( _surv_rate_group == NULL, "pre-condition" ); 619 assert( is_young(), "pre-condition" ); 620 621 _surv_rate_group = surv_rate_group; 622 _age_index = surv_rate_group->next_age_index(); 623 } 624 625 void uninstall_surv_rate_group() { 626 if (_surv_rate_group != NULL) { 627 assert( _age_index > -1, "pre-condition" ); 628 assert( is_young(), "pre-condition" ); 629 630 _surv_rate_group = NULL; 631 _age_index = -1; 632 } else { 633 assert( _age_index == -1, "pre-condition" ); 634 } 635 } 636 637 void set_free() { _type.set_free(); } 638 639 void set_eden() { _type.set_eden(); } 640 void set_eden_pre_gc() { _type.set_eden_pre_gc(); } 641 void set_survivor() { _type.set_survivor(); } 642 643 void set_old() { _type.set_old(); } 644 645 void set_archive() { _type.set_archive(); } 646 647 // Determine if an object has been allocated since the last 648 // mark performed by the collector. This returns true iff the object 649 // is within the unmarked area of the region. 650 bool obj_allocated_since_prev_marking(oop obj) const { 651 return (HeapWord *) obj >= prev_top_at_mark_start(); 652 } 653 bool obj_allocated_since_next_marking(oop obj) const { 654 return (HeapWord *) obj >= next_top_at_mark_start(); 655 } 656 657 // Returns the "evacuation_failed" property of the region. 658 bool evacuation_failed() { return _evacuation_failed; } 659 660 // Sets the "evacuation_failed" property of the region. 661 void set_evacuation_failed(bool b) { 662 _evacuation_failed = b; 663 664 if (b) { 665 _next_marked_bytes = 0; 666 } 667 } 668 669 // Requires that "mr" be entirely within the region. 670 // Apply "cl->do_object" to all objects that intersect with "mr". 671 // If the iteration encounters an unparseable portion of the region, 672 // or if "cl->abort()" is true after a closure application, 673 // terminate the iteration and return the address of the start of the 674 // subregion that isn't done. (The two can be distinguished by querying 675 // "cl->abort()".) Return of "NULL" indicates that the iteration 676 // completed. 677 HeapWord* 678 object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl); 679 680 // filter_young: if true and the region is a young region then we 681 // skip the iteration. 682 // card_ptr: if not NULL, and we decide that the card is not young 683 // and we iterate over it, we'll clean the card before we start the 684 // iteration. 685 HeapWord* 686 oops_on_card_seq_iterate_careful(MemRegion mr, 687 FilterOutOfRegionClosure* cl, 688 bool filter_young, 689 jbyte* card_ptr); 690 691 size_t recorded_rs_length() const { return _recorded_rs_length; } 692 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 693 size_t predicted_bytes_to_copy() const { return _predicted_bytes_to_copy; } 694 695 void set_recorded_rs_length(size_t rs_length) { 696 _recorded_rs_length = rs_length; 697 } 698 699 void set_predicted_elapsed_time_ms(double ms) { 700 _predicted_elapsed_time_ms = ms; 701 } 702 703 void set_predicted_bytes_to_copy(size_t bytes) { 704 _predicted_bytes_to_copy = bytes; 705 } 706 707 virtual CompactibleSpace* next_compaction_space() const; 708 709 virtual void reset_after_compaction(); 710 711 // Routines for managing a list of code roots (attached to the 712 // this region's RSet) that point into this heap region. 713 void add_strong_code_root(nmethod* nm); 714 void add_strong_code_root_locked(nmethod* nm); 715 void remove_strong_code_root(nmethod* nm); 716 717 // Applies blk->do_code_blob() to each of the entries in 718 // the strong code roots list for this region 719 void strong_code_roots_do(CodeBlobClosure* blk) const; 720 721 // Verify that the entries on the strong code root list for this 722 // region are live and include at least one pointer into this region. 723 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 724 725 void print() const; 726 void print_on(outputStream* st) const; 727 728 // vo == UsePrevMarking -> use "prev" marking information, 729 // vo == UseNextMarking -> use "next" marking information 730 // vo == UseMarkWord -> use the mark word in the object header 731 // 732 // NOTE: Only the "prev" marking information is guaranteed to be 733 // consistent most of the time, so most calls to this should use 734 // vo == UsePrevMarking. 735 // Currently, there is only one case where this is called with 736 // vo == UseNextMarking, which is to verify the "next" marking 737 // information at the end of remark. 738 // Currently there is only one place where this is called with 739 // vo == UseMarkWord, which is to verify the marking during a 740 // full GC. 741 void verify(VerifyOption vo, bool *failures) const; 742 743 // Override; it uses the "prev" marking information 744 virtual void verify() const; 745 }; 746 747 // HeapRegionClosure is used for iterating over regions. 748 // Terminates the iteration when the "doHeapRegion" method returns "true". 749 class HeapRegionClosure : public StackObj { 750 friend class HeapRegionManager; 751 friend class G1CollectedHeap; 752 753 bool _complete; 754 void incomplete() { _complete = false; } 755 756 public: 757 HeapRegionClosure(): _complete(true) {} 758 759 // Typically called on each region until it returns true. 760 virtual bool doHeapRegion(HeapRegion* r) = 0; 761 762 // True after iteration if the closure was applied to all heap regions 763 // and returned "false" in all cases. 764 bool complete() { return _complete; } 765 }; 766 767 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP