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 G1CMBitMapRO; 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 address, and either the 224 // size of the object (if live) or the size of the block (if dead) in size. 225 // Performs some optimizations if is_gc_active is set. 226 template <bool is_gc_active> 227 inline bool is_obj_dead_with_size(const oop obj, G1CMBitMapRO* bitmap, size_t* size) const; 228 229 protected: 230 // The index of this region in the heap region sequence. 231 uint _hrm_index; 232 233 AllocationContext_t _allocation_context; 234 235 HeapRegionType _type; 236 237 // For a humongous region, region in which it starts. 238 HeapRegion* _humongous_start_region; 239 240 // True iff an attempt to evacuate an object in the region failed. 241 bool _evacuation_failed; 242 243 // Fields used by the HeapRegionSetBase class and subclasses. 244 HeapRegion* _next; 245 HeapRegion* _prev; 246 #ifdef ASSERT 247 HeapRegionSetBase* _containing_set; 248 #endif // ASSERT 249 250 // We use concurrent marking to determine the amount of live data 251 // in each heap region. 252 size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. 253 size_t _next_marked_bytes; // Bytes known to be live via in-progress marking. 254 255 // The calculated GC efficiency of the region. 256 double _gc_efficiency; 257 258 int _young_index_in_cset; 259 SurvRateGroup* _surv_rate_group; 260 int _age_index; 261 262 // The start of the unmarked area. The unmarked area extends from this 263 // word until the top and/or end of the region, and is the part 264 // of the region for which no marking was done, i.e. objects may 265 // have been allocated in this part since the last mark phase. 266 // "prev" is the top at the start of the last completed marking. 267 // "next" is the top at the start of the in-progress marking (if any.) 268 HeapWord* _prev_top_at_mark_start; 269 HeapWord* _next_top_at_mark_start; 270 // If a collection pause is in progress, this is the top at the start 271 // of that pause. 272 273 void init_top_at_mark_start() { 274 assert(_prev_marked_bytes == 0 && 275 _next_marked_bytes == 0, 276 "Must be called after zero_marked_bytes."); 277 HeapWord* bot = bottom(); 278 _prev_top_at_mark_start = bot; 279 _next_top_at_mark_start = bot; 280 } 281 282 // Cached attributes used in the collection set policy information 283 284 // The RSet length that was added to the total value 285 // for the collection set. 286 size_t _recorded_rs_length; 287 288 // The predicted elapsed time that was added to total value 289 // for the collection set. 290 double _predicted_elapsed_time_ms; 291 292 // Returns the object size for all valid block starts. Must only be called for 293 // blocks with an address < top(). 294 size_t block_size_during_gc(const HeapWord* p, const G1CMBitMapRO* bitmap) const; 295 296 // Iterate over the references in a humongous objects and apply the given closure 297 // to them. 298 // Humongous objects are allocated directly in the old-gen. So we need special 299 // handling for concurrent processing encountering an in-progress allocation. 300 template <class Closure, bool is_gc_active> 301 inline bool do_oops_on_card_in_humongous(MemRegion mr, 302 Closure* cl, 303 G1CollectedHeap* g1h); 304 public: 305 HeapRegion(uint hrm_index, 306 G1BlockOffsetTable* bot, 307 MemRegion mr); 308 309 // Initializing the HeapRegion not only resets the data structure, but also 310 // resets the BOT for that heap region. 311 // The default values for clear_space means that we will do the clearing if 312 // there's clearing to be done ourselves. We also always mangle the space. 313 virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle); 314 315 static int LogOfHRGrainBytes; 316 static int LogOfHRGrainWords; 317 318 static size_t GrainBytes; 319 static size_t GrainWords; 320 static size_t CardsPerRegion; 321 322 static size_t align_up_to_region_byte_size(size_t sz) { 323 return (sz + (size_t) GrainBytes - 1) & 324 ~((1 << (size_t) LogOfHRGrainBytes) - 1); 325 } 326 327 328 // Returns whether a field is in the same region as the obj it points to. 329 template <typename T> 330 static bool is_in_same_region(T* p, oop obj) { 331 assert(p != NULL, "p can't be NULL"); 332 assert(obj != NULL, "obj can't be NULL"); 333 return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0; 334 } 335 336 static size_t max_region_size(); 337 static size_t min_region_size_in_words(); 338 339 // It sets up the heap region size (GrainBytes / GrainWords), as 340 // well as other related fields that are based on the heap region 341 // size (LogOfHRGrainBytes / LogOfHRGrainWords / 342 // CardsPerRegion). All those fields are considered constant 343 // throughout the JVM's execution, therefore they should only be set 344 // up once during initialization time. 345 static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); 346 347 // All allocated blocks are occupied by objects in a HeapRegion 348 bool block_is_obj(const HeapWord* p) const; 349 350 // Returns the object size for all valid block starts 351 // and the amount of unallocated words if called on top() 352 size_t block_size(const HeapWord* p) const; 353 354 // Override for scan_and_forward support. 355 void prepare_for_compaction(CompactPoint* cp); 356 357 inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size); 358 inline HeapWord* allocate_no_bot_updates(size_t word_size); 359 inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size); 360 361 // If this region is a member of a HeapRegionManager, the index in that 362 // sequence, otherwise -1. 363 uint hrm_index() const { return _hrm_index; } 364 365 // The number of bytes marked live in the region in the last marking phase. 366 size_t marked_bytes() { return _prev_marked_bytes; } 367 size_t live_bytes() { 368 return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes(); 369 } 370 371 // The number of bytes counted in the next marking. 372 size_t next_marked_bytes() { return _next_marked_bytes; } 373 // The number of bytes live wrt the next marking. 374 size_t next_live_bytes() { 375 return 376 (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes(); 377 } 378 379 // A lower bound on the amount of garbage bytes in the region. 380 size_t garbage_bytes() { 381 size_t used_at_mark_start_bytes = 382 (prev_top_at_mark_start() - bottom()) * HeapWordSize; 383 return used_at_mark_start_bytes - marked_bytes(); 384 } 385 386 // Return the amount of bytes we'll reclaim if we collect this 387 // region. This includes not only the known garbage bytes in the 388 // region but also any unallocated space in it, i.e., [top, end), 389 // since it will also be reclaimed if we collect the region. 390 size_t reclaimable_bytes() { 391 size_t known_live_bytes = live_bytes(); 392 assert(known_live_bytes <= capacity(), "sanity"); 393 return capacity() - known_live_bytes; 394 } 395 396 // An upper bound on the number of live bytes in the region. 397 size_t max_live_bytes() { return used() - garbage_bytes(); } 398 399 void add_to_marked_bytes(size_t incr_bytes) { 400 _next_marked_bytes = _next_marked_bytes + incr_bytes; 401 } 402 403 void zero_marked_bytes() { 404 _prev_marked_bytes = _next_marked_bytes = 0; 405 } 406 407 const char* get_type_str() const { return _type.get_str(); } 408 const char* get_short_type_str() const { return _type.get_short_str(); } 409 G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); } 410 411 bool is_free() const { return _type.is_free(); } 412 413 bool is_young() const { return _type.is_young(); } 414 bool is_eden() const { return _type.is_eden(); } 415 bool is_survivor() const { return _type.is_survivor(); } 416 417 bool is_humongous() const { return _type.is_humongous(); } 418 bool is_starts_humongous() const { return _type.is_starts_humongous(); } 419 bool is_continues_humongous() const { return _type.is_continues_humongous(); } 420 421 bool is_old() const { return _type.is_old(); } 422 423 bool is_old_or_humongous() const { return _type.is_old_or_humongous(); } 424 425 // A pinned region contains objects which are not moved by garbage collections. 426 // Humongous regions and archive regions are pinned. 427 bool is_pinned() const { return _type.is_pinned(); } 428 429 // An archive region is a pinned region, also tagged as old, which 430 // should not be marked during mark/sweep. This allows the address 431 // space to be shared by JVM instances. 432 bool is_archive() const { return _type.is_archive(); } 433 434 // For a humongous region, region in which it starts. 435 HeapRegion* humongous_start_region() const { 436 return _humongous_start_region; 437 } 438 439 // Makes the current region be a "starts humongous" region, i.e., 440 // the first region in a series of one or more contiguous regions 441 // that will contain a single "humongous" object. 442 // 443 // obj_top : points to the top of the humongous object. 444 // fill_size : size of the filler object at the end of the region series. 445 void set_starts_humongous(HeapWord* obj_top, size_t fill_size); 446 447 // Makes the current region be a "continues humongous' 448 // region. first_hr is the "start humongous" region of the series 449 // which this region will be part of. 450 void set_continues_humongous(HeapRegion* first_hr); 451 452 // Unsets the humongous-related fields on the region. 453 void clear_humongous(); 454 455 // If the region has a remembered set, return a pointer to it. 456 HeapRegionRemSet* rem_set() const { 457 return _rem_set; 458 } 459 460 inline bool in_collection_set() const; 461 462 void set_allocation_context(AllocationContext_t context) { 463 _allocation_context = context; 464 } 465 466 AllocationContext_t allocation_context() const { 467 return _allocation_context; 468 } 469 470 // Methods used by the HeapRegionSetBase class and subclasses. 471 472 // Getter and setter for the next and prev fields used to link regions into 473 // linked lists. 474 HeapRegion* next() { return _next; } 475 HeapRegion* prev() { return _prev; } 476 477 void set_next(HeapRegion* next) { _next = next; } 478 void set_prev(HeapRegion* prev) { _prev = prev; } 479 480 // Every region added to a set is tagged with a reference to that 481 // set. This is used for doing consistency checking to make sure that 482 // the contents of a set are as they should be and it's only 483 // available in non-product builds. 484 #ifdef ASSERT 485 void set_containing_set(HeapRegionSetBase* containing_set) { 486 assert((containing_set == NULL && _containing_set != NULL) || 487 (containing_set != NULL && _containing_set == NULL), 488 "containing_set: " PTR_FORMAT " " 489 "_containing_set: " PTR_FORMAT, 490 p2i(containing_set), p2i(_containing_set)); 491 492 _containing_set = containing_set; 493 } 494 495 HeapRegionSetBase* containing_set() { return _containing_set; } 496 #else // ASSERT 497 void set_containing_set(HeapRegionSetBase* containing_set) { } 498 499 // containing_set() is only used in asserts so there's no reason 500 // to provide a dummy version of it. 501 #endif // ASSERT 502 503 504 // Reset the HeapRegion to default values. 505 // If skip_remset is true, do not clear the remembered set. 506 void hr_clear(bool skip_remset, bool clear_space, bool locked = false); 507 // Clear the parts skipped by skip_remset in hr_clear() in the HeapRegion during 508 // a concurrent phase. 509 void par_clear(); 510 511 // Get the start of the unmarked area in this region. 512 HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; } 513 HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; } 514 515 // Note the start or end of marking. This tells the heap region 516 // that the collector is about to start or has finished (concurrently) 517 // marking the heap. 518 519 // Notify the region that concurrent marking is starting. Initialize 520 // all fields related to the next marking info. 521 inline void note_start_of_marking(); 522 523 // Notify the region that concurrent marking has finished. Copy the 524 // (now finalized) next marking info fields into the prev marking 525 // info fields. 526 inline void note_end_of_marking(); 527 528 // Notify the region that it will be used as to-space during a GC 529 // and we are about to start copying objects into it. 530 inline void note_start_of_copying(bool during_initial_mark); 531 532 // Notify the region that it ceases being to-space during a GC and 533 // we will not copy objects into it any more. 534 inline void note_end_of_copying(bool during_initial_mark); 535 536 // Notify the region that we are about to start processing 537 // self-forwarded objects during evac failure handling. 538 void note_self_forwarding_removal_start(bool during_initial_mark, 539 bool during_conc_mark); 540 541 // Notify the region that we have finished processing self-forwarded 542 // objects during evac failure handling. 543 void note_self_forwarding_removal_end(size_t marked_bytes); 544 545 // Returns "false" iff no object in the region was allocated when the 546 // last mark phase ended. 547 bool is_marked() { return _prev_top_at_mark_start != bottom(); } 548 549 void reset_during_compaction() { 550 assert(is_humongous(), 551 "should only be called for humongous regions"); 552 553 zero_marked_bytes(); 554 init_top_at_mark_start(); 555 } 556 557 void calc_gc_efficiency(void); 558 double gc_efficiency() { return _gc_efficiency;} 559 560 int young_index_in_cset() const { return _young_index_in_cset; } 561 void set_young_index_in_cset(int index) { 562 assert( (index == -1) || is_young(), "pre-condition" ); 563 _young_index_in_cset = index; 564 } 565 566 int age_in_surv_rate_group() { 567 assert( _surv_rate_group != NULL, "pre-condition" ); 568 assert( _age_index > -1, "pre-condition" ); 569 return _surv_rate_group->age_in_group(_age_index); 570 } 571 572 void record_surv_words_in_group(size_t words_survived) { 573 assert( _surv_rate_group != NULL, "pre-condition" ); 574 assert( _age_index > -1, "pre-condition" ); 575 int age_in_group = age_in_surv_rate_group(); 576 _surv_rate_group->record_surviving_words(age_in_group, words_survived); 577 } 578 579 int age_in_surv_rate_group_cond() { 580 if (_surv_rate_group != NULL) 581 return age_in_surv_rate_group(); 582 else 583 return -1; 584 } 585 586 SurvRateGroup* surv_rate_group() { 587 return _surv_rate_group; 588 } 589 590 void install_surv_rate_group(SurvRateGroup* surv_rate_group) { 591 assert( surv_rate_group != NULL, "pre-condition" ); 592 assert( _surv_rate_group == NULL, "pre-condition" ); 593 assert( is_young(), "pre-condition" ); 594 595 _surv_rate_group = surv_rate_group; 596 _age_index = surv_rate_group->next_age_index(); 597 } 598 599 void uninstall_surv_rate_group() { 600 if (_surv_rate_group != NULL) { 601 assert( _age_index > -1, "pre-condition" ); 602 assert( is_young(), "pre-condition" ); 603 604 _surv_rate_group = NULL; 605 _age_index = -1; 606 } else { 607 assert( _age_index == -1, "pre-condition" ); 608 } 609 } 610 611 void set_free(); 612 613 void set_eden(); 614 void set_eden_pre_gc(); 615 void set_survivor(); 616 617 void set_old(); 618 619 void set_archive(); 620 621 // Determine if an object has been allocated since the last 622 // mark performed by the collector. This returns true iff the object 623 // is within the unmarked area of the region. 624 bool obj_allocated_since_prev_marking(oop obj) const { 625 return (HeapWord *) obj >= prev_top_at_mark_start(); 626 } 627 bool obj_allocated_since_next_marking(oop obj) const { 628 return (HeapWord *) obj >= next_top_at_mark_start(); 629 } 630 631 // Returns the "evacuation_failed" property of the region. 632 bool evacuation_failed() { return _evacuation_failed; } 633 634 // Sets the "evacuation_failed" property of the region. 635 void set_evacuation_failed(bool b) { 636 _evacuation_failed = b; 637 638 if (b) { 639 _next_marked_bytes = 0; 640 } 641 } 642 643 // Iterate over the objects overlapping part of a card, applying cl 644 // to all references in the region. This is a helper for 645 // G1RemSet::refine_card, and is tightly coupled with it. 646 // mr: the memory region covered by the card, trimmed to the 647 // allocated space for this region. Must not be empty. 648 // This region must be old or humongous. 649 // Returns true if the designated objects were successfully 650 // processed, false if an unparsable part of the heap was 651 // encountered; that only happens when invoked concurrently with the 652 // mutator. 653 template <bool is_gc_active, class Closure> 654 inline bool oops_on_card_seq_iterate_careful(MemRegion mr, Closure* cl); 655 656 size_t recorded_rs_length() const { return _recorded_rs_length; } 657 double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; } 658 659 void set_recorded_rs_length(size_t rs_length) { 660 _recorded_rs_length = rs_length; 661 } 662 663 void set_predicted_elapsed_time_ms(double ms) { 664 _predicted_elapsed_time_ms = ms; 665 } 666 667 virtual CompactibleSpace* next_compaction_space() const; 668 669 virtual void reset_after_compaction(); 670 671 // Routines for managing a list of code roots (attached to the 672 // this region's RSet) that point into this heap region. 673 void add_strong_code_root(nmethod* nm); 674 void add_strong_code_root_locked(nmethod* nm); 675 void remove_strong_code_root(nmethod* nm); 676 677 // Applies blk->do_code_blob() to each of the entries in 678 // the strong code roots list for this region 679 void strong_code_roots_do(CodeBlobClosure* blk) const; 680 681 // Verify that the entries on the strong code root list for this 682 // region are live and include at least one pointer into this region. 683 void verify_strong_code_roots(VerifyOption vo, bool* failures) const; 684 685 void print() const; 686 void print_on(outputStream* st) const; 687 688 // vo == UsePrevMarking -> use "prev" marking information, 689 // vo == UseNextMarking -> use "next" marking information 690 // vo == UseMarkWord -> use the mark word in the object header 691 // 692 // NOTE: Only the "prev" marking information is guaranteed to be 693 // consistent most of the time, so most calls to this should use 694 // vo == UsePrevMarking. 695 // Currently, there is only one case where this is called with 696 // vo == UseNextMarking, which is to verify the "next" marking 697 // information at the end of remark. 698 // Currently there is only one place where this is called with 699 // vo == UseMarkWord, which is to verify the marking during a 700 // full GC. 701 void verify(VerifyOption vo, bool *failures) const; 702 703 // Override; it uses the "prev" marking information 704 virtual void verify() const; 705 706 void verify_rem_set(VerifyOption vo, bool *failures) const; 707 void verify_rem_set() const; 708 }; 709 710 // HeapRegionClosure is used for iterating over regions. 711 // Terminates the iteration when the "doHeapRegion" method returns "true". 712 class HeapRegionClosure : public StackObj { 713 friend class HeapRegionManager; 714 friend class G1CollectionSet; 715 716 bool _complete; 717 void incomplete() { _complete = false; } 718 719 public: 720 HeapRegionClosure(): _complete(true) {} 721 722 // Typically called on each region until it returns true. 723 virtual bool doHeapRegion(HeapRegion* r) = 0; 724 725 // True after iteration if the closure was applied to all heap regions 726 // and returned "false" in all cases. 727 bool complete() { return _complete; } 728 }; 729 730 #endif // SHARE_VM_GC_G1_HEAPREGION_HPP