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 G1CMBitMap; 60 class HeapRegionRemSet; 61 class HeapRegionRemSetIterator; 62 class HeapRegion; 63 class HeapRegionSetBase; 64 class nmethod; 65 66 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]" 67 #define HR_FORMAT_PARAMS(_hr_) \ 68 (_hr_)->hrm_index(), \ 69 (_hr_)->get_short_type_str(), \ 70 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end()) 71 72 // sentinel value for hrm_index 73 #define G1_NO_HRM_INDEX ((uint) -1) 74 75 // The complicating factor is that BlockOffsetTable diverged 76 // significantly, and we need functionality that is only in the G1 version. 77 // So I copied that code, which led to an alternate G1 version of 78 // OffsetTableContigSpace. If the two versions of BlockOffsetTable could 79 // be reconciled, then G1OffsetTableContigSpace could go away. 80 81 // The idea behind time stamps is the following. We want to keep track of 82 // the highest address where it's safe to scan objects for each region. 83 // This is only relevant for current GC alloc regions so we keep a time stamp 84 // per region to determine if the region has been allocated during the current 85 // GC or not. If the time stamp is current we report a scan_top value which 86 // was saved at the end of the previous GC for retained alloc regions and which is 87 // equal to the bottom for all other regions. 88 // There is a race between card scanners and allocating gc workers where we must ensure 89 // that card scanners do not read the memory allocated by the gc workers. 90 // In order to enforce that, we must not return a value of _top which is more recent than the 91 // time stamp. This is due to the fact that a region may become a gc alloc region at 92 // some point after we've read the timestamp value as being < the current time stamp. 93 // The time stamps are re-initialized to zero at cleanup and at Full GCs. 94 // The current scheme that uses sequential unsigned ints will fail only if we have 4b 95 // evacuation pauses between two cleanups, which is _highly_ unlikely. 96 class G1ContiguousSpace: public CompactibleSpace { 97 friend class VMStructs; 98 HeapWord* volatile _top; 99 protected: 100 G1BlockOffsetTablePart _bot_part; 101 Mutex _par_alloc_lock; 102 volatile uint _gc_time_stamp; 103 // When we need to retire an allocation region, while other threads 104 // are also concurrently trying to allocate into it, we typically 105 // allocate a dummy object at the end of the region to ensure that 106 // no more allocations can take place in it. However, sometimes we 107 // want to know where the end of the last "real" object we allocated 108 // into the region was and this is what this keeps track. 109 HeapWord* _pre_dummy_top; 110 111 public: 112 G1ContiguousSpace(G1BlockOffsetTable* bot); 113 114 void set_top(HeapWord* value) { _top = value; } 115 HeapWord* top() const { return _top; } 116 117 protected: 118 // Reset the G1ContiguousSpace. 119 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); 120 121 HeapWord* volatile* top_addr() { return &_top; } 122 // Try to allocate at least min_word_size and up to desired_size from this Space. 123 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 124 // space allocated. 125 // This version assumes that all allocation requests to this Space are properly 126 // synchronized. 127 inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 128 // Try to allocate at least min_word_size and up to desired_size from this Space. 129 // Returns NULL if not possible, otherwise sets actual_word_size to the amount of 130 // space allocated. 131 // This version synchronizes with other calls to par_allocate_impl(). 132 inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 133 134 public: 135 void reset_after_compaction() { set_top(compaction_top()); } 136 137 size_t used() const { return byte_size(bottom(), top()); } 138 size_t free() const { return byte_size(top(), end()); } 139 bool is_free_block(const HeapWord* p) const { return p >= top(); } 140 141 MemRegion used_region() const { return MemRegion(bottom(), top()); } 142 143 void object_iterate(ObjectClosure* blk); 144 void safe_object_iterate(ObjectClosure* blk); 145 146 void mangle_unused_area() PRODUCT_RETURN; 147 void mangle_unused_area_complete() PRODUCT_RETURN; 148 149 void record_timestamp(); 150 void reset_gc_time_stamp() { _gc_time_stamp = 0; } 151 uint get_gc_time_stamp() { return _gc_time_stamp; } 152 153 // See the comment above in the declaration of _pre_dummy_top for an 154 // explanation of what it is. 155 void set_pre_dummy_top(HeapWord* pre_dummy_top) { 156 assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition"); 157 _pre_dummy_top = pre_dummy_top; 158 } 159 HeapWord* pre_dummy_top() { 160 return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top; 161 } 162 void reset_pre_dummy_top() { _pre_dummy_top = NULL; } 163 164 virtual void clear(bool mangle_space); 165 166 HeapWord* block_start(const void* p); 167 HeapWord* block_start_const(const void* p) const; 168 169 // Allocation (return NULL if full). Assumes the caller has established 170 // mutually exclusive access to the space. 171 HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 172 // Allocation (return NULL if full). Enforces mutual exclusion internally. 173 HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size); 174 175 virtual HeapWord* allocate(size_t word_size); 176 virtual HeapWord* par_allocate(size_t word_size); 177 178 HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; } 179 180 // MarkSweep support phase3 181 virtual HeapWord* initialize_threshold(); 182 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); 183 184 virtual void print() const; 185 186 void reset_bot() { 187 _bot_part.reset_bot(); 188 } 189 190 void print_bot_on(outputStream* out) { 191 _bot_part.print_on(out); 192 } 193 }; 194 195 class HeapRegion: public G1ContiguousSpace { 196 friend class VMStructs; 197 // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class 198 template <typename SpaceType> 199 friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp); 200 private: 201 202 // The remembered set for this region. 203 // (Might want to make this "inline" later, to avoid some alloc failure 204 // issues.) 205 HeapRegionRemSet* _rem_set; 206 207 // Auxiliary functions for scan_and_forward support. 208 // See comments for CompactibleSpace for more information. 209 inline HeapWord* scan_limit() const { 210 return top(); 211 } 212 213 inline bool scanned_block_is_obj(const HeapWord* addr) const { 214 return true; // Always true, since scan_limit is top 215 } 216 217 inline size_t scanned_block_size(const HeapWord* addr) const { 218 return HeapRegion::block_size(addr); // Avoid virtual call 219 } 220 221 void report_region_type_change(G1HeapRegionTraceType::Type to); 222 223 // Returns whether the given object address refers to a dead object, and either the 224 // size of the object (if live) or the size of the block (if dead) in size. 225 // May 226 // - only called with obj < top() 227 // - not called on humongous objects or archive regions 228 inline bool is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const; 229 230 protected: 231 // The index of this region in the heap region sequence. 232 uint _hrm_index; 233 234 AllocationContext_t _allocation_context; 235 236 HeapRegionType _type; 237 238 // For a humongous region, region in which it starts. 239 HeapRegion* _humongous_start_region; 240 241 // True iff an attempt to evacuate an object in the region failed. 242 bool _evacuation_failed; 243 244 // Fields used by the HeapRegionSetBase class and subclasses. 245 HeapRegion* _next; 246 HeapRegion* _prev; 247 #ifdef ASSERT 248 HeapRegionSetBase* _containing_set; 249 #endif // ASSERT 250 251 // We use concurrent marking to determine the amount of live data 252 // in each heap region. 253 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 254 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 255 256 // The calculated GC efficiency of the region. 257 double _gc_efficiency; 258 259 int _young_index_in_cset; 260 SurvRateGroup* _surv_rate_group; 261 int _age_index; 262 263 // The start of the unmarked area. The unmarked area extends from this 264 // word until the top and/or end of the region, and is the part 265 // of the region for which no marking was done, i.e. objects may 266 // have been allocated in this part since the last mark phase. 267 // "prev" is the top at the start of the last completed marking. 268 // "next" is the top at the start of the in-progress marking (if any.) 269 HeapWord* _prev_top_at_mark_start; 270 HeapWord* _next_top_at_mark_start; 271 // If a collection pause is in progress, this is the top at the start 272 // of that pause. 273 274 void init_top_at_mark_start() { 275 assert(_prev_marked_bytes == 0 && 276 _next_marked_bytes == 0, 277 "Must be called after zero_marked_bytes."); 278 HeapWord* bot = bottom(); 279 _prev_top_at_mark_start = bot; 280 _next_top_at_mark_start = bot; 281 } 282 283 // Cached attributes used in the collection set policy information 284 285 // The RSet length that was added to the total value 286 // for the collection set. 287 size_t _recorded_rs_length; 288 289 // The predicted elapsed time that was added to total value 290 // for the collection set. 291 double _predicted_elapsed_time_ms; 292 293 // Iterate over the references in a humongous objects and apply the given closure 294 // to them. 295 // Humongous objects are allocated directly in the old-gen. So we need special 296 // handling for concurrent processing encountering an in-progress allocation. 297 template <class Closure, bool is_gc_active> 298 inline bool do_oops_on_card_in_humongous(MemRegion mr, 299 Closure* cl, 300 G1CollectedHeap* g1h); 301 302 // Returns the block size of the given (dead, potentially having its class unloaded) object 303 // starting at p extending to at most the prev TAMS using the given mark bitmap. 304 inline size_t block_size_using_bitmap(const HeapWord* p, const G1CMBitMap* const prev_bitmap) const; 305 public: 306 HeapRegion(uint hrm_index, 307 G1BlockOffsetTable* bot, 308 MemRegion mr); 309 310 // Initializing the HeapRegion not only resets the data structure, but also 311 // resets the BOT for that heap region. 312 // The default values for clear_space means that we will do the clearing if 313 // there's clearing to be done ourselves. We also always mangle the space. 314 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 315 316 static int LogOfHRGrainBytes; 317 static int LogOfHRGrainWords; 318 319 static size_t GrainBytes; 320 static size_t GrainWords; 321 static size_t CardsPerRegion; 322 323 static size_t align_up_to_region_byte_size(size_t sz) { 324 return (sz + (size_t) GrainBytes - 1) & 325 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 326 } 327 328 329 // Returns whether a field is in the same region as the obj it points to. 330 template <typename T> 331 static bool is_in_same_region(T* p, oop obj) { 332 assert(p != NULL, "p can't be NULL"); 333 assert(obj != NULL, "obj can't be NULL"); 334 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0; 335 } 336 337 static size_t max_region_size(); 338 static size_t min_region_size_in_words(); 339 340 // It sets up the heap region size (GrainBytes / GrainWords), as 341 // well as other related fields that are based on the heap region 342 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 343 // CardsPerRegion). All those fields are considered constant 344 // throughout the JVM's execution, therefore they should only be set 345 // up once during initialization time. 346 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); 347 348 // All allocated blocks are occupied by objects in a HeapRegion 349 bool block_is_obj(const HeapWord* p) const; 350 351 // Returns whether the given object is dead based on TAMS and bitmap. 352 bool is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const; 353 354 // Returns the object size for all valid block starts 355 // and the amount of unallocated words if called on top() 356 size_t block_size(const HeapWord* p) const; 357 358 // Override for scan_and_forward support. 359 void prepare_for_compaction(CompactPoint* cp); 360 361 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size); 362 inline HeapWord* allocate_no_bot_updates(size_t word_size); 363 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size); 364 365 // If this region is a member of a HeapRegionManager, the index in that 366 // sequence, otherwise -1. 367 uint hrm_index() const { return _hrm_index; } 368 369 // The number of bytes marked live in the region in the last marking phase. 370 size_t marked_bytes() { return _prev_marked_bytes; } 371 size_t live_bytes() { 372 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 373 } 374 375 // The number of bytes counted in the next marking. 376 size_t next_marked_bytes() { return _next_marked_bytes; } 377 // The number of bytes live wrt the next marking. 378 size_t next_live_bytes() { 379 return 380 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 381 } 382 383 // A lower bound on the amount of garbage bytes in the region. 384 size_t garbage_bytes() { 385 size_t used_at_mark_start_bytes = 386 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 387 return used_at_mark_start_bytes - marked_bytes(); 388 } 389 390 // Return the amount of bytes we'll reclaim if we collect this 391 // region. This includes not only the known garbage bytes in the 392 // region but also any unallocated space in it, i.e., [top, end), 393 // since it will also be reclaimed if we collect the region. 394 size_t reclaimable_bytes() { 395 size_t known_live_bytes = live_bytes(); 396 assert(known_live_bytes <= capacity(), "sanity"); 397 return capacity() - known_live_bytes; 398 } 399 400 // An upper bound on the number of live bytes in the region. 401 size_t max_live_bytes() { return used() - garbage_bytes(); } 402 403 void add_to_marked_bytes(size_t incr_bytes) { 404 _next_marked_bytes = _next_marked_bytes + incr_bytes; 405 } 406 407 void zero_marked_bytes() { 408 _prev_marked_bytes = _next_marked_bytes = 0; 409 } 410 411 const char* get_type_str() const { return _type.get_str(); } 412 const char* get_short_type_str() const { return _type.get_short_str(); } 413 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); } 414 415 bool is_free() const { return _type.is_free(); } 416 417 bool is_young() const { return _type.is_young(); } 418 bool is_eden() const { return _type.is_eden(); } 419 bool is_survivor() const { return _type.is_survivor(); } 420 421 bool is_humongous() const { return _type.is_humongous(); } 422 bool is_starts_humongous() const { return _type.is_starts_humongous(); } 423 bool is_continues_humongous() const { return _type.is_continues_humongous(); } 424 425 bool is_old() const { return _type.is_old(); } 426 427 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); } 428 429 // A pinned region contains objects which are not moved by garbage collections. 430 // Humongous regions and archive regions are pinned. 431 bool is_pinned() const { return _type.is_pinned(); } 432 433 // An archive region is a pinned region, also tagged as old, which 434 // should not be marked during mark/sweep. This allows the address 435 // space to be shared by JVM instances. 436 bool is_archive() const { return _type.is_archive(); } 437 438 // For a humongous region, region in which it starts. 439 HeapRegion* humongous_start_region() const { 440 return _humongous_start_region; 441 } 442 443 // Makes the current region be a "starts humongous" region, i.e., 444 // the first region in a series of one or more contiguous regions 445 // that will contain a single "humongous" object. 446 // 447 // obj_top : points to the top of the humongous object. 448 // fill_size : size of the filler object at the end of the region series. 449 void set_starts_humongous(HeapWord* obj_top, size_t fill_size); 450 451 // Makes the current region be a "continues humongous' 452 // region. first_hr is the "start humongous" region of the series 453 // which this region will be part of. 454 void set_continues_humongous(HeapRegion* first_hr); 455 456 // Unsets the humongous-related fields on the region. 457 void clear_humongous(); 458 459 // If the region has a remembered set, return a pointer to it. 460 HeapRegionRemSet* rem_set() const { 461 return _rem_set; 462 } 463 464 inline bool in_collection_set() const; 465 466 void set_allocation_context(AllocationContext_t context) { 467 _allocation_context = context; 468 } 469 470 AllocationContext_t allocation_context() const { 471 return _allocation_context; 472 } 473 474 // Methods used by the HeapRegionSetBase class and subclasses. 475 476 // Getter and setter for the next and prev fields used to link regions into 477 // linked lists. 478 HeapRegion* next() { return _next; } 479 HeapRegion* prev() { return _prev; } 480 481 void set_next(HeapRegion* next) { _next = next; } 482 void set_prev(HeapRegion* prev) { _prev = prev; } 483 484 // Every region added to a set is tagged with a reference to that 485 // set. This is used for doing consistency checking to make sure that 486 // the contents of a set are as they should be and it's only 487 // available in non-product builds. 488 #ifdef ASSERT 489 void set_containing_set(HeapRegionSetBase* containing_set) { 490 assert((containing_set == NULL && _containing_set != NULL) || 491 (containing_set != NULL && _containing_set == NULL), 492 "containing_set: " PTR_FORMAT " " 493 "_containing_set: " PTR_FORMAT, 494 p2i(containing_set), p2i(_containing_set)); 495 496 _containing_set = containing_set; 497 } 498 499 HeapRegionSetBase* containing_set() { return _containing_set; } 500 #else // ASSERT 501 void set_containing_set(HeapRegionSetBase* containing_set) { } 502 503 // containing_set() is only used in asserts so there's no reason 504 // to provide a dummy version of it. 505 #endif // ASSERT 506 507 508 // Reset the HeapRegion to default values. 509 // If skip_remset is true, do not clear the remembered set. 510 void hr_clear(bool skip_remset, bool clear_space, bool locked = false); 511 // Clear the parts skipped by skip_remset in hr_clear() in the HeapRegion during 512 // a concurrent phase. 513 void par_clear(); 514 515 // Get the start of the unmarked area in this region. 516 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 517 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 518 519 // Note the start or end of marking. This tells the heap region 520 // that the collector is about to start or has finished (concurrently) 521 // marking the heap. 522 523 // Notify the region that concurrent marking is starting. Initialize 524 // all fields related to the next marking info. 525 inline void note_start_of_marking(); 526 527 // Notify the region that concurrent marking has finished. Copy the 528 // (now finalized) next marking info fields into the prev marking 529 // info fields. 530 inline void note_end_of_marking(); 531 532 // Notify the region that it will be used as to-space during a GC 533 // and we are about to start copying objects into it. 534 inline void note_start_of_copying(bool during_initial_mark); 535 536 // Notify the region that it ceases being to-space during a GC and 537 // we will not copy objects into it any more. 538 inline void note_end_of_copying(bool during_initial_mark); 539 540 // Notify the region that we are about to start processing 541 // self-forwarded objects during evac failure handling. 542 void note_self_forwarding_removal_start(bool during_initial_mark, 543 bool during_conc_mark); 544 545 // Notify the region that we have finished processing self-forwarded 546 // objects during evac failure handling. 547 void note_self_forwarding_removal_end(size_t marked_bytes); 548 549 // Returns "false" iff no object in the region was allocated when the 550 // last mark phase ended. 551 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 552 553 void reset_during_compaction() { 554 assert(is_humongous(), 555 "should only be called for humongous regions"); 556 557 zero_marked_bytes(); 558 init_top_at_mark_start(); 559 } 560 561 void calc_gc_efficiency(void); 562 double gc_efficiency() { return _gc_efficiency;} 563 564 int young_index_in_cset() const { return _young_index_in_cset; } 565 void set_young_index_in_cset(int index) { 566 assert( (index == -1) || is_young(), "pre-condition" ); 567 _young_index_in_cset = index; 568 } 569 570 int age_in_surv_rate_group() { 571 assert( _surv_rate_group != NULL, "pre-condition" ); 572 assert( _age_index > -1, "pre-condition" ); 573 return _surv_rate_group->age_in_group(_age_index); 574 } 575 576 void record_surv_words_in_group(size_t words_survived) { 577 assert( _surv_rate_group != NULL, "pre-condition" ); 578 assert( _age_index > -1, "pre-condition" ); 579 int age_in_group = age_in_surv_rate_group(); 580 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 581 } 582 583 int age_in_surv_rate_group_cond() { 584 if (_surv_rate_group != NULL) 585 return age_in_surv_rate_group(); 586 else 587 return -1; 588 } 589 590 SurvRateGroup* surv_rate_group() { 591 return _surv_rate_group; 592 } 593 594 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 595 assert( surv_rate_group != NULL, "pre-condition" ); 596 assert( _surv_rate_group == NULL, "pre-condition" ); 597 assert( is_young(), "pre-condition" ); 598 599 _surv_rate_group = surv_rate_group; 600 _age_index = surv_rate_group->next_age_index(); 601 } 602 603 void uninstall_surv_rate_group() { 604 if (_surv_rate_group != NULL) { 605 assert( _age_index > -1, "pre-condition" ); 606 assert( is_young(), "pre-condition" ); 607 608 _surv_rate_group = NULL; 609 _age_index = -1; 610 } else { 611 assert( _age_index == -1, "pre-condition" ); 612 } 613 } 614 615 void set_free(); 616 617 void set_eden(); 618 void set_eden_pre_gc(); 619 void set_survivor(); 620 621 void set_old(); 622 623 void set_archive(); 624 625 // Determine if an object has been allocated since the last 626 // mark performed by the collector. This returns true iff the object 627 // is within the unmarked area of the region. 628 bool obj_allocated_since_prev_marking(oop obj) const { 629 return (HeapWord *) obj >= prev_top_at_mark_start(); 630 } 631 bool obj_allocated_since_next_marking(oop obj) const { 632 return (HeapWord *) obj >= next_top_at_mark_start(); 633 } 634 635 // Returns the "evacuation_failed" property of the region. 636 bool evacuation_failed() { return _evacuation_failed; } 637 638 // Sets the "evacuation_failed" property of the region. 639 void set_evacuation_failed(bool b) { 640 _evacuation_failed = b; 641 642 if (b) { 643 _next_marked_bytes = 0; 644 } 645 } 646 647 // Iterate over the objects overlapping part of a card, applying cl 648 // to all references in the region. This is a helper for 649 // G1RemSet::refine_card*, and is tightly coupled with them. 650 // mr is the memory region covered by the card, trimmed to the 651 // allocated space for this region. Must not be empty. 652 // This region must be old or humongous. 653 // Returns true if the designated objects were successfully 654 // processed, false if an unparsable part of the heap was 655 // encountered; that only happens when invoked concurrently with the 656 // mutator. 657 template <bool is_gc_active, class Closure> 658 inline bool oops_on_card_seq_iterate_careful(MemRegion mr, Closure* cl); 659 660 size_t recorded_rs_length() const { return _recorded_rs_length; } 661 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 662 663 void set_recorded_rs_length(size_t rs_length) { 664 _recorded_rs_length = rs_length; 665 } 666 667 void set_predicted_elapsed_time_ms(double ms) { 668 _predicted_elapsed_time_ms = ms; 669 } 670 671 virtual CompactibleSpace* next_compaction_space() const; 672 673 virtual void reset_after_compaction(); 674 675 // Routines for managing a list of code roots (attached to the 676 // this region's RSet) that point into this heap region. 677 void add_strong_code_root(nmethod* nm); 678 void add_strong_code_root_locked(nmethod* nm); 679 void remove_strong_code_root(nmethod* nm); 680 681 // Applies blk->do_code_blob() to each of the entries in 682 // the strong code roots list for this region 683 void strong_code_roots_do(CodeBlobClosure* blk) const; 684 685 // Verify that the entries on the strong code root list for this 686 // region are live and include at least one pointer into this region. 687 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 688 689 void print() const; 690 void print_on(outputStream* st) const; 691 692 // vo == UsePrevMarking -> use "prev" marking information, 693 // vo == UseNextMarking -> use "next" marking information 694 // vo == UseMarkWord -> use the mark word in the object header 695 // 696 // NOTE: Only the "prev" marking information is guaranteed to be 697 // consistent most of the time, so most calls to this should use 698 // vo == UsePrevMarking. 699 // Currently, there is only one case where this is called with 700 // vo == UseNextMarking, which is to verify the "next" marking 701 // information at the end of remark. 702 // Currently there is only one place where this is called with 703 // vo == UseMarkWord, which is to verify the marking during a 704 // full GC. 705 void verify(VerifyOption vo, bool *failures) const; 706 707 // Override; it uses the "prev" marking information 708 virtual void verify() const; 709 710 void verify_rem_set(VerifyOption vo, bool *failures) const; 711 void verify_rem_set() const; 712 }; 713 714 // HeapRegionClosure is used for iterating over regions. 715 // Terminates the iteration when the "doHeapRegion" method returns "true". 716 class HeapRegionClosure : public StackObj { 717 friend class HeapRegionManager; 718 friend class G1CollectionSet; 719 720 bool _complete; 721 void incomplete() { _complete = false; } 722 723 public: 724 HeapRegionClosure(): _complete(true) {} 725 726 // Typically called on each region until it returns true. 727 virtual bool doHeapRegion(HeapRegion* r) = 0; 728 729 // True after iteration if the closure was applied to all heap regions 730 // and returned "false" in all cases. 731 bool complete() { return _complete; } 732 }; 733 734 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP