1 /* 2 * Copyright (c) 2001, 2017, 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/g1HeapRegionTraceType.hpp" 31 #include "gc/g1/heapRegionTracer.hpp" 32 #include "gc/g1/heapRegionType.hpp" 33 #include "gc/g1/survRateGroup.hpp" 34 #include "gc/shared/ageTable.hpp" 35 #include "gc/shared/spaceDecorator.hpp" 36 #include "utilities/macros.hpp" 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 // Each heap region is self contained. top() and end() can never 49 // be set beyond the end of the region. For humongous objects, 50 // the first region is a StartsHumongous region. If the humongous 51 // object is larger than a heap region, the following regions will 52 // be of type ContinuesHumongous. In this case the top() of the 53 // StartHumongous region and all ContinuesHumongous regions except 54 // the last will point to their own end. The last ContinuesHumongous 55 // region may have top() equal the end of object if there isn't 56 // room for filler objects to pad out to the end of the region. 57 58 class G1CollectedHeap; 59 class HeapRegionRemSet; 60 class HeapRegionRemSetIterator; 61 class HeapRegion; 62 class HeapRegionSetBase; 63 class nmethod; 64 65 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]" 66 #define HR_FORMAT_PARAMS(_hr_) \ 67 (_hr_)->hrm_index(), \ 68 (_hr_)->get_short_type_str(), \ 69 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 70 71 // sentinel value for hrm_index 72 #define G1_NO_HRM_INDEX ((uint) -1) 73 74 // A dirty card to oop closure for heap regions. It 75 // knows how to get the G1 heap and how to use the bitmap 76 // in the concurrent marker used by G1 to filter remembered 77 // sets. 78 79 class HeapRegionDCTOC : public DirtyCardToOopClosure { 80 private: 81 HeapRegion* _hr; 82 G1ParPushHeapRSClosure* _rs_scan; 83 G1CollectedHeap* _g1; 84 85 // Walk the given memory region from bottom to (actual) top 86 // looking for objects and applying the oop closure (_cl) to 87 // them. The base implementation of this treats the area as 88 // blocks, where a block may or may not be an object. Sub- 89 // classes should override this to provide more accurate 90 // or possibly more efficient walking. 91 void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); 92 93 public: 94 HeapRegionDCTOC(G1CollectedHeap* g1, 95 HeapRegion* hr, 96 G1ParPushHeapRSClosure* cl, 97 CardTableModRefBS::PrecisionStyle precision); 98 }; 99 100 // The complicating factor is that BlockOffsetTable diverged 101 // significantly, and we need functionality that is only in the G1 version. 102 // So I copied that code, which led to an alternate G1 version of 103 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 104 // be reconciled, then G1OffsetTableContigSpace could go away. 105 106 // The idea behind time stamps is the following. We want to keep track of 107 // the highest address where it's safe to scan objects for each region. 108 // This is only relevant for current GC alloc regions so we keep a time stamp 109 // per region to determine if the region has been allocated during the current 110 // GC or not. If the time stamp is current we report a scan_top value which 111 // was saved at the end of the previous GC for retained alloc regions and which is 112 // equal to the bottom for all other regions. 113 // There is a race between card scanners and allocating gc workers where we must ensure 114 // that card scanners do not read the memory allocated by the gc workers. 115 // In order to enforce that, we must not return a value of _top which is more recent than the 116 // time stamp. This is due to the fact that a region may become a gc alloc region at 117 // some point after we've read the timestamp value as being < the current time stamp. 118 // The time stamps are re-initialized to zero at cleanup and at Full GCs. 119 // The current scheme that uses sequential unsigned ints will fail only if we have 4b 120 // evacuation pauses between two cleanups, which is _highly_ unlikely. 121 class G1ContiguousSpace: public CompactibleSpace { 122 friend class VMStructs; 123 HeapWord* volatile _top; 124 HeapWord* volatile _scan_top; 125 protected: 126 G1BlockOffsetTablePart _bot_part; 127 Mutex _par_alloc_lock; 128 volatile uint _gc_time_stamp; 129 // When we need to retire an allocation region, while other threads 130 // are also concurrently trying to allocate into it, we typically 131 // allocate a dummy object at the end of the region to ensure that 132 // no more allocations can take place in it. However, sometimes we 133 // want to know where the end of the last "real" object we allocated 134 // into the region was and this is what this keeps track. 135 HeapWord* _pre_dummy_top; 136 137 public: 138 G1ContiguousSpace(G1BlockOffsetTable* bot); 139 140 void set_top(HeapWord* value) { _top = value; } 141 HeapWord* top() const { return _top; } 142 143 protected: 144 // Reset the G1ContiguousSpace. 145 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 146 147 HeapWord* volatile* top_addr() { return &_top; } 148 // Try to allocate at least min_word_size and up to desired_size from this Space. 149 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 150 // space allocated. 151 // This version assumes that all allocation requests to this Space are properly 152 // synchronized. 153 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 154 // Try to allocate at least min_word_size and up to desired_size from this Space. 155 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 156 // space allocated. 157 // This version synchronizes with other calls to par_allocate_impl(). 158 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 159 160 public: 161 void reset_after_compaction() { set_top(compaction_top()); } 162 163 size_t used() const { return byte_size(bottom(), top()); } 164 size_t free() const { return byte_size(top(), end()); } 165 bool is_free_block(const HeapWord* p) const { return p >= top(); } 166 167 MemRegion used_region() const { return MemRegion(bottom(), top()); } 168 169 void object_iterate(ObjectClosure* blk); 170 void safe_object_iterate(ObjectClosure* blk); 171 172 void mangle_unused_area() PRODUCT_RETURN; 173 void mangle_unused_area_complete() PRODUCT_RETURN; 174 175 HeapWord* scan_top() const; 176 void record_timestamp(); 177 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 178 uint get_gc_time_stamp() { return _gc_time_stamp; } 179 void record_retained_region(); 180 181 // See the comment above in the declaration of _pre_dummy_top for an 182 // explanation of what it is. 183 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 184 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 185 _pre_dummy_top = pre_dummy_top; 186 } 187 HeapWord* pre_dummy_top() { 188 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 189 } 190 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 191 192 virtual void clear(bool mangle_space); 193 194 HeapWord* block_start(const void* p); 195 HeapWord* block_start_const(const void* p) const; 196 197 // Allocation (return NULL if full). Assumes the caller has established 198 // mutually exclusive access to the space. 199 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 200 // Allocation (return NULL if full). Enforces mutual exclusion internally. 201 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 202 203 virtual HeapWord* allocate(size_t word_size); 204 virtual HeapWord* par_allocate(size_t word_size); 205 206 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; } 207 208 // MarkSweep support phase3 209 virtual HeapWord* initialize_threshold(); 210 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 211 212 virtual void print() const; 213 214 void reset_bot() { 215 _bot_part.reset_bot(); 216 } 217 218 void print_bot_on(outputStream* out) { 219 _bot_part.print_on(out); 220 } 221 }; 222 223 class HeapRegion: public G1ContiguousSpace { 224 friend class VMStructs; 225 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class 226 template <typename SpaceType> 227 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp); 228 private: 229 230 // The remembered set for this region. 231 // (Might want to make this "inline" later, to avoid some alloc failure 232 // issues.) 233 HeapRegionRemSet* _rem_set; 234 235 // Auxiliary functions for scan_and_forward support. 236 // See comments for CompactibleSpace for more information. 237 inline HeapWord* scan_limit() const { 238 return top(); 239 } 240 241 inline bool scanned_block_is_obj(const HeapWord* addr) const { 242 return true; // Always true, since scan_limit is top 243 } 244 245 inline size_t scanned_block_size(const HeapWord* addr) const { 246 return HeapRegion::block_size(addr); // Avoid virtual call 247 } 248 249 void report_region_type_change(G1HeapRegionTraceType::Type to); 250 251 protected: 252 // The index of this region in the heap region sequence. 253 uint _hrm_index; 254 255 AllocationContext_t _allocation_context; 256 257 HeapRegionType _type; 258 259 // For a humongous region, region in which it starts. 260 HeapRegion* _humongous_start_region; 261 262 // True iff an attempt to evacuate an object in the region failed. 263 bool _evacuation_failed; 264 265 // Fields used by the HeapRegionSetBase class and subclasses. 266 HeapRegion* _next; 267 HeapRegion* _prev; 268 #ifdef ASSERT 269 HeapRegionSetBase* _containing_set; 270 #endif // ASSERT 271 272 // We use concurrent marking to determine the amount of live data 273 // in each heap region. 274 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 275 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 276 277 // The calculated GC efficiency of the region. 278 double _gc_efficiency; 279 280 int _young_index_in_cset; 281 SurvRateGroup* _surv_rate_group; 282 int _age_index; 283 284 // The start of the unmarked area. The unmarked area extends from this 285 // word until the top and/or end of the region, and is the part 286 // of the region for which no marking was done, i.e. objects may 287 // have been allocated in this part since the last mark phase. 288 // "prev" is the top at the start of the last completed marking. 289 // "next" is the top at the start of the in-progress marking (if any.) 290 HeapWord* _prev_top_at_mark_start; 291 HeapWord* _next_top_at_mark_start; 292 // If a collection pause is in progress, this is the top at the start 293 // of that pause. 294 295 void init_top_at_mark_start() { 296 assert(_prev_marked_bytes == 0 && 297 _next_marked_bytes == 0, 298 "Must be called after zero_marked_bytes."); 299 HeapWord* bot = bottom(); 300 _prev_top_at_mark_start = bot; 301 _next_top_at_mark_start = bot; 302 } 303 304 // Cached attributes used in the collection set policy information 305 306 // The RSet length that was added to the total value 307 // for the collection set. 308 size_t _recorded_rs_length; 309 310 // The predicted elapsed time that was added to total value 311 // for the collection set. 312 double _predicted_elapsed_time_ms; 313 314 public: 315 HeapRegion(uint hrm_index, 316 G1BlockOffsetTable* bot, 317 MemRegion mr); 318 319 // Initializing the HeapRegion not only resets the data structure, but also 320 // resets the BOT for that heap region. 321 // The default values for clear_space means that we will do the clearing if 322 // there's clearing to be done ourselves. We also always mangle the space. 323 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 324 325 static int LogOfHRGrainBytes; 326 static int LogOfHRGrainWords; 327 328 static size_t GrainBytes; 329 static size_t GrainWords; 330 static size_t CardsPerRegion; 331 332 static size_t align_up_to_region_byte_size(size_t sz) { 333 return (sz + (size_t) GrainBytes - 1) & 334 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 335 } 336 337 338 // Returns whether a field is in the same region as the obj it points to. 339 template <typename T> 340 static bool is_in_same_region(T* p, oop obj) { 341 assert(p != NULL, "p can't be NULL"); 342 assert(obj != NULL, "obj can't be NULL"); 343 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0; 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 return used_at_mark_start_bytes - marked_bytes(); 394 } 395 396 // Return the amount of bytes we'll reclaim if we collect this 397 // region. This includes not only the known garbage bytes in the 398 // region but also any unallocated space in it, i.e., [top, end), 399 // since it will also be reclaimed if we collect the region. 400 size_t reclaimable_bytes() { 401 size_t known_live_bytes = live_bytes(); 402 assert(known_live_bytes <= capacity(), "sanity"); 403 return capacity() - known_live_bytes; 404 } 405 406 // An upper bound on the number of live bytes in the region. 407 size_t max_live_bytes() { return used() - garbage_bytes(); } 408 409 void add_to_marked_bytes(size_t incr_bytes) { 410 _next_marked_bytes = _next_marked_bytes + incr_bytes; 411 } 412 413 void zero_marked_bytes() { 414 _prev_marked_bytes = _next_marked_bytes = 0; 415 } 416 417 const char* get_type_str() const { return _type.get_str(); } 418 const char* get_short_type_str() const { return _type.get_short_str(); } 419 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); } 420 421 bool is_free() const { return _type.is_free(); } 422 423 bool is_young() const { return _type.is_young(); } 424 bool is_eden() const { return _type.is_eden(); } 425 bool is_survivor() const { return _type.is_survivor(); } 426 427 bool is_humongous() const { return _type.is_humongous(); } 428 bool is_starts_humongous() const { return _type.is_starts_humongous(); } 429 bool is_continues_humongous() const { return _type.is_continues_humongous(); } 430 431 bool is_old() const { return _type.is_old(); } 432 433 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); } 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 // Makes the current region be a "starts humongous" region, i.e., 450 // the first region in a series of one or more contiguous regions 451 // that will contain a single "humongous" object. 452 // 453 // obj_top : points to the top of the humongous object. 454 // fill_size : size of the filler object at the end of the region series. 455 void set_starts_humongous(HeapWord* obj_top, size_t fill_size); 456 457 // Makes the current region be a "continues humongous' 458 // region. first_hr is the "start humongous" region of the series 459 // which this region will be part of. 460 void set_continues_humongous(HeapRegion* first_hr); 461 462 // Unsets the humongous-related fields on the region. 463 void clear_humongous(); 464 465 // If the region has a remembered set, return a pointer to it. 466 HeapRegionRemSet* rem_set() const { 467 return _rem_set; 468 } 469 470 inline bool in_collection_set() const; 471 472 void set_allocation_context(AllocationContext_t context) { 473 _allocation_context = context; 474 } 475 476 AllocationContext_t allocation_context() const { 477 return _allocation_context; 478 } 479 480 // Methods used by the HeapRegionSetBase class and subclasses. 481 482 // Getter and setter for the next and prev fields used to link regions into 483 // linked lists. 484 HeapRegion* next() { return _next; } 485 HeapRegion* prev() { return _prev; } 486 487 void set_next(HeapRegion* next) { _next = next; } 488 void set_prev(HeapRegion* prev) { _prev = prev; } 489 490 // Every region added to a set is tagged with a reference to that 491 // set. This is used for doing consistency checking to make sure that 492 // the contents of a set are as they should be and it's only 493 // available in non-product builds. 494 #ifdef ASSERT 495 void set_containing_set(HeapRegionSetBase* containing_set) { 496 assert((containing_set == NULL && _containing_set != NULL) || 497 (containing_set != NULL && _containing_set == NULL), 498 "containing_set: " PTR_FORMAT " " 499 "_containing_set: " PTR_FORMAT, 500 p2i(containing_set), p2i(_containing_set)); 501 502 _containing_set = containing_set; 503 } 504 505 HeapRegionSetBase* containing_set() { return _containing_set; } 506 #else // ASSERT 507 void set_containing_set(HeapRegionSetBase* containing_set) { } 508 509 // containing_set() is only used in asserts so there's no reason 510 // to provide a dummy version of it. 511 #endif // ASSERT 512 513 514 // Reset the HeapRegion to default values. 515 // If skip_remset is true, do not clear the remembered set. 516 void hr_clear(bool skip_remset, bool clear_space, bool locked = false); 517 // Clear the parts skipped by skip_remset in hr_clear() in the HeapRegion during 518 // a concurrent phase. 519 void par_clear(); 520 521 // Get the start of the unmarked area in this region. 522 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 523 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 524 525 // Note the start or end of marking. This tells the heap region 526 // that the collector is about to start or has finished (concurrently) 527 // marking the heap. 528 529 // Notify the region that concurrent marking is starting. Initialize 530 // all fields related to the next marking info. 531 inline void note_start_of_marking(); 532 533 // Notify the region that concurrent marking has finished. Copy the 534 // (now finalized) next marking info fields into the prev marking 535 // info fields. 536 inline void note_end_of_marking(); 537 538 // Notify the region that it will be used as to-space during a GC 539 // and we are about to start copying objects into it. 540 inline void note_start_of_copying(bool during_initial_mark); 541 542 // Notify the region that it ceases being to-space during a GC and 543 // we will not copy objects into it any more. 544 inline void note_end_of_copying(bool during_initial_mark); 545 546 // Notify the region that we are about to start processing 547 // self-forwarded objects during evac failure handling. 548 void note_self_forwarding_removal_start(bool during_initial_mark, 549 bool during_conc_mark); 550 551 // Notify the region that we have finished processing self-forwarded 552 // objects during evac failure handling. 553 void note_self_forwarding_removal_end(size_t marked_bytes); 554 555 // Returns "false" iff no object in the region was allocated when the 556 // last mark phase ended. 557 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 558 559 void reset_during_compaction() { 560 assert(is_humongous(), 561 "should only be called for humongous regions"); 562 563 zero_marked_bytes(); 564 init_top_at_mark_start(); 565 } 566 567 void calc_gc_efficiency(void); 568 double gc_efficiency() { return _gc_efficiency;} 569 570 int young_index_in_cset() const { return _young_index_in_cset; } 571 void set_young_index_in_cset(int index) { 572 assert( (index == -1) || is_young(), "pre-condition" ); 573 _young_index_in_cset = index; 574 } 575 576 int age_in_surv_rate_group() { 577 assert( _surv_rate_group != NULL, "pre-condition" ); 578 assert( _age_index > -1, "pre-condition" ); 579 return _surv_rate_group->age_in_group(_age_index); 580 } 581 582 void record_surv_words_in_group(size_t words_survived) { 583 assert( _surv_rate_group != NULL, "pre-condition" ); 584 assert( _age_index > -1, "pre-condition" ); 585 int age_in_group = age_in_surv_rate_group(); 586 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 587 } 588 589 int age_in_surv_rate_group_cond() { 590 if (_surv_rate_group != NULL) 591 return age_in_surv_rate_group(); 592 else 593 return -1; 594 } 595 596 SurvRateGroup* surv_rate_group() { 597 return _surv_rate_group; 598 } 599 600 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 601 assert( surv_rate_group != NULL, "pre-condition" ); 602 assert( _surv_rate_group == NULL, "pre-condition" ); 603 assert( is_young(), "pre-condition" ); 604 605 _surv_rate_group = surv_rate_group; 606 _age_index = surv_rate_group->next_age_index(); 607 } 608 609 void uninstall_surv_rate_group() { 610 if (_surv_rate_group != NULL) { 611 assert( _age_index > -1, "pre-condition" ); 612 assert( is_young(), "pre-condition" ); 613 614 _surv_rate_group = NULL; 615 _age_index = -1; 616 } else { 617 assert( _age_index == -1, "pre-condition" ); 618 } 619 } 620 621 void set_free(); 622 623 void set_eden(); 624 void set_eden_pre_gc(); 625 void set_survivor(); 626 627 void set_old(); 628 629 void set_archive(); 630 631 // Determine if an object has been allocated since the last 632 // mark performed by the collector. This returns true iff the object 633 // is within the unmarked area of the region. 634 bool obj_allocated_since_prev_marking(oop obj) const { 635 return (HeapWord *) obj >= prev_top_at_mark_start(); 636 } 637 bool obj_allocated_since_next_marking(oop obj) const { 638 return (HeapWord *) obj >= next_top_at_mark_start(); 639 } 640 641 // Returns the "evacuation_failed" property of the region. 642 bool evacuation_failed() { return _evacuation_failed; } 643 644 // Sets the "evacuation_failed" property of the region. 645 void set_evacuation_failed(bool b) { 646 _evacuation_failed = b; 647 648 if (b) { 649 _next_marked_bytes = 0; 650 } 651 } 652 653 // Iterate over the objects overlapping part of a card, applying cl 654 // to all references in the region. This is a helper for 655 // G1RemSet::refine_card, and is tightly coupled with it. 656 // mr: the memory region covered by the card, trimmed to the 657 // allocated space for this region. Must not be empty. 658 // This region must be old or humongous. 659 // Returns true if the designated objects were successfully 660 // processed, false if an unparsable part of the heap was 661 // encountered; that only happens when invoked concurrently with the 662 // mutator. 663 bool oops_on_card_seq_iterate_careful(MemRegion mr, 664 G1UpdateRSOrPushRefOopClosure* cl); 665 666 size_t recorded_rs_length() const { return _recorded_rs_length; } 667 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 668 669 void set_recorded_rs_length(size_t rs_length) { 670 _recorded_rs_length = rs_length; 671 } 672 673 void set_predicted_elapsed_time_ms(double ms) { 674 _predicted_elapsed_time_ms = ms; 675 } 676 677 virtual CompactibleSpace* next_compaction_space() const; 678 679 virtual void reset_after_compaction(); 680 681 // Routines for managing a list of code roots (attached to the 682 // this region's RSet) that point into this heap region. 683 void add_strong_code_root(nmethod* nm); 684 void add_strong_code_root_locked(nmethod* nm); 685 void remove_strong_code_root(nmethod* nm); 686 687 // Applies blk->do_code_blob() to each of the entries in 688 // the strong code roots list for this region 689 void strong_code_roots_do(CodeBlobClosure* blk) const; 690 691 // Verify that the entries on the strong code root list for this 692 // region are live and include at least one pointer into this region. 693 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 694 695 void print() const; 696 void print_on(outputStream* st) const; 697 698 // vo == UsePrevMarking -> use "prev" marking information, 699 // vo == UseNextMarking -> use "next" marking information 700 // vo == UseMarkWord -> use the mark word in the object header 701 // 702 // NOTE: Only the "prev" marking information is guaranteed to be 703 // consistent most of the time, so most calls to this should use 704 // vo == UsePrevMarking. 705 // Currently, there is only one case where this is called with 706 // vo == UseNextMarking, which is to verify the "next" marking 707 // information at the end of remark. 708 // Currently there is only one place where this is called with 709 // vo == UseMarkWord, which is to verify the marking during a 710 // full GC. 711 void verify(VerifyOption vo, bool *failures) const; 712 713 // Override; it uses the "prev" marking information 714 virtual void verify() const; 715 716 void verify_rem_set(VerifyOption vo, bool *failures) const; 717 void verify_rem_set() const; 718 }; 719 720 // HeapRegionClosure is used for iterating over regions. 721 // Terminates the iteration when the "doHeapRegion" method returns "true". 722 class HeapRegionClosure : public StackObj { 723 friend class HeapRegionManager; 724 friend class G1CollectionSet; 725 726 bool _complete; 727 void incomplete() { _complete = false; } 728 729 public: 730 HeapRegionClosure(): _complete(true) {} 731 732 // Typically called on each region until it returns true. 733 virtual bool doHeapRegion(HeapRegion* r) = 0; 734 735 // True after iteration if the closure was applied to all heap regions 736 // and returned "false" in all cases. 737 bool complete() { return _complete; } 738 }; 739 740 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP