1 /* 2 * Copyright (c) 2001, 2013, 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_IMPLEMENTATION_G1_CONCURRENTMARK_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_HPP 27 28 #include "classfile/javaClasses.hpp" 29 #include "gc_implementation/g1/heapRegionSet.hpp" 30 #include "gc_implementation/shared/gcId.hpp" 31 #include "utilities/taskqueue.hpp" 32 33 class G1CollectedHeap; 34 class CMTask; 35 typedef GenericTaskQueue<oop, mtGC> CMTaskQueue; 36 typedef GenericTaskQueueSet<CMTaskQueue, mtGC> CMTaskQueueSet; 37 38 // Closure used by CM during concurrent reference discovery 39 // and reference processing (during remarking) to determine 40 // if a particular object is alive. It is primarily used 41 // to determine if referents of discovered reference objects 42 // are alive. An instance is also embedded into the 43 // reference processor as the _is_alive_non_header field 44 class G1CMIsAliveClosure: public BoolObjectClosure { 45 G1CollectedHeap* _g1; 46 public: 47 G1CMIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) { } 48 49 bool do_object_b(oop obj); 50 }; 51 52 // A generic CM bit map. This is essentially a wrapper around the BitMap 53 // class, with one bit per (1<<_shifter) HeapWords. 54 55 class CMBitMapRO VALUE_OBJ_CLASS_SPEC { 56 protected: 57 HeapWord* _bmStartWord; // base address of range covered by map 58 size_t _bmWordSize; // map size (in #HeapWords covered) 59 const int _shifter; // map to char or bit 60 VirtualSpace _virtual_space; // underlying the bit map 61 BitMap _bm; // the bit map itself 62 63 public: 64 // constructor 65 CMBitMapRO(int shifter); 66 67 enum { do_yield = true }; 68 69 // inquiries 70 HeapWord* startWord() const { return _bmStartWord; } 71 size_t sizeInWords() const { return _bmWordSize; } 72 // the following is one past the last word in space 73 HeapWord* endWord() const { return _bmStartWord + _bmWordSize; } 74 75 // read marks 76 77 bool isMarked(HeapWord* addr) const { 78 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), 79 "outside underlying space?"); 80 return _bm.at(heapWordToOffset(addr)); 81 } 82 83 // iteration 84 inline bool iterate(BitMapClosure* cl, MemRegion mr); 85 inline bool iterate(BitMapClosure* cl); 86 87 // Return the address corresponding to the next marked bit at or after 88 // "addr", and before "limit", if "limit" is non-NULL. If there is no 89 // such bit, returns "limit" if that is non-NULL, or else "endWord()". 90 HeapWord* getNextMarkedWordAddress(const HeapWord* addr, 91 const HeapWord* limit = NULL) const; 92 // Return the address corresponding to the next unmarked bit at or after 93 // "addr", and before "limit", if "limit" is non-NULL. If there is no 94 // such bit, returns "limit" if that is non-NULL, or else "endWord()". 95 HeapWord* getNextUnmarkedWordAddress(const HeapWord* addr, 96 const HeapWord* limit = NULL) const; 97 98 // conversion utilities 99 HeapWord* offsetToHeapWord(size_t offset) const { 100 return _bmStartWord + (offset << _shifter); 101 } 102 size_t heapWordToOffset(const HeapWord* addr) const { 103 return pointer_delta(addr, _bmStartWord) >> _shifter; 104 } 105 int heapWordDiffToOffsetDiff(size_t diff) const; 106 107 // The argument addr should be the start address of a valid object 108 HeapWord* nextObject(HeapWord* addr) { 109 oop obj = (oop) addr; 110 HeapWord* res = addr + obj->size(); 111 assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity"); 112 return res; 113 } 114 115 void print_on_error(outputStream* st, const char* prefix) const; 116 117 // debugging 118 NOT_PRODUCT(bool covers(ReservedSpace rs) const;) 119 }; 120 121 class CMBitMap : public CMBitMapRO { 122 123 public: 124 // constructor 125 CMBitMap(int shifter) : 126 CMBitMapRO(shifter) {} 127 128 // Allocates the back store for the marking bitmap 129 bool allocate(ReservedSpace heap_rs); 130 131 // write marks 132 void mark(HeapWord* addr) { 133 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), 134 "outside underlying space?"); 135 _bm.set_bit(heapWordToOffset(addr)); 136 } 137 void clear(HeapWord* addr) { 138 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), 139 "outside underlying space?"); 140 _bm.clear_bit(heapWordToOffset(addr)); 141 } 142 bool parMark(HeapWord* addr) { 143 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), 144 "outside underlying space?"); 145 return _bm.par_set_bit(heapWordToOffset(addr)); 146 } 147 bool parClear(HeapWord* addr) { 148 assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize), 149 "outside underlying space?"); 150 return _bm.par_clear_bit(heapWordToOffset(addr)); 151 } 152 void markRange(MemRegion mr); 153 void clearAll(); 154 void clearRange(MemRegion mr); 155 156 // Starting at the bit corresponding to "addr" (inclusive), find the next 157 // "1" bit, if any. This bit starts some run of consecutive "1"'s; find 158 // the end of this run (stopping at "end_addr"). Return the MemRegion 159 // covering from the start of the region corresponding to the first bit 160 // of the run to the end of the region corresponding to the last bit of 161 // the run. If there is no "1" bit at or after "addr", return an empty 162 // MemRegion. 163 MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr); 164 }; 165 166 // Represents a marking stack used by ConcurrentMarking in the G1 collector. 167 class CMMarkStack VALUE_OBJ_CLASS_SPEC { 168 VirtualSpace _virtual_space; // Underlying backing store for actual stack 169 ConcurrentMark* _cm; 170 oop* _base; // bottom of stack 171 jint _index; // one more than last occupied index 172 jint _capacity; // max #elements 173 jint _saved_index; // value of _index saved at start of GC 174 NOT_PRODUCT(jint _max_depth;) // max depth plumbed during run 175 176 bool _overflow; 177 bool _should_expand; 178 DEBUG_ONLY(bool _drain_in_progress;) 179 DEBUG_ONLY(bool _drain_in_progress_yields;) 180 181 public: 182 CMMarkStack(ConcurrentMark* cm); 183 ~CMMarkStack(); 184 185 #ifndef PRODUCT 186 jint max_depth() const { 187 return _max_depth; 188 } 189 #endif 190 191 bool allocate(size_t capacity); 192 193 oop pop() { 194 if (!isEmpty()) { 195 return _base[--_index] ; 196 } 197 return NULL; 198 } 199 200 // If overflow happens, don't do the push, and record the overflow. 201 // *Requires* that "ptr" is already marked. 202 void push(oop ptr) { 203 if (isFull()) { 204 // Record overflow. 205 _overflow = true; 206 return; 207 } else { 208 _base[_index++] = ptr; 209 NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index)); 210 } 211 } 212 // Non-block impl. Note: concurrency is allowed only with other 213 // "par_push" operations, not with "pop" or "drain". We would need 214 // parallel versions of them if such concurrency was desired. 215 void par_push(oop ptr); 216 217 // Pushes the first "n" elements of "ptr_arr" on the stack. 218 // Non-block impl. Note: concurrency is allowed only with other 219 // "par_adjoin_arr" or "push" operations, not with "pop" or "drain". 220 void par_adjoin_arr(oop* ptr_arr, int n); 221 222 // Pushes the first "n" elements of "ptr_arr" on the stack. 223 // Locking impl: concurrency is allowed only with 224 // "par_push_arr" and/or "par_pop_arr" operations, which use the same 225 // locking strategy. 226 void par_push_arr(oop* ptr_arr, int n); 227 228 // If returns false, the array was empty. Otherwise, removes up to "max" 229 // elements from the stack, and transfers them to "ptr_arr" in an 230 // unspecified order. The actual number transferred is given in "n" ("n 231 // == 0" is deliberately redundant with the return value.) Locking impl: 232 // concurrency is allowed only with "par_push_arr" and/or "par_pop_arr" 233 // operations, which use the same locking strategy. 234 bool par_pop_arr(oop* ptr_arr, int max, int* n); 235 236 // Drain the mark stack, applying the given closure to all fields of 237 // objects on the stack. (That is, continue until the stack is empty, 238 // even if closure applications add entries to the stack.) The "bm" 239 // argument, if non-null, may be used to verify that only marked objects 240 // are on the mark stack. If "yield_after" is "true", then the 241 // concurrent marker performing the drain offers to yield after 242 // processing each object. If a yield occurs, stops the drain operation 243 // and returns false. Otherwise, returns true. 244 template<bool nv, typename OopClosureClass> 245 bool drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after = false); 246 247 bool isEmpty() { return _index == 0; } 248 bool isFull() { return _index == _capacity; } 249 int maxElems() { return _capacity; } 250 251 bool overflow() { return _overflow; } 252 void clear_overflow() { _overflow = false; } 253 254 bool should_expand() const { return _should_expand; } 255 void set_should_expand(); 256 257 // Expand the stack, typically in response to an overflow condition 258 void expand(); 259 260 int size() { return _index; } 261 262 void setEmpty() { _index = 0; clear_overflow(); } 263 264 // Record the current index. 265 void note_start_of_gc(); 266 267 // Make sure that we have not added any entries to the stack during GC. 268 void note_end_of_gc(); 269 270 // iterate over the oops in the mark stack, up to the bound recorded via 271 // the call above. 272 void oops_do(OopClosure* f); 273 }; 274 275 class ForceOverflowSettings VALUE_OBJ_CLASS_SPEC { 276 private: 277 #ifndef PRODUCT 278 uintx _num_remaining; 279 bool _force; 280 #endif // !defined(PRODUCT) 281 282 public: 283 void init() PRODUCT_RETURN; 284 void update() PRODUCT_RETURN; 285 bool should_force() PRODUCT_RETURN_( return false; ); 286 }; 287 288 // this will enable a variety of different statistics per GC task 289 #define _MARKING_STATS_ 0 290 // this will enable the higher verbose levels 291 #define _MARKING_VERBOSE_ 0 292 293 #if _MARKING_STATS_ 294 #define statsOnly(statement) \ 295 do { \ 296 statement ; \ 297 } while (0) 298 #else // _MARKING_STATS_ 299 #define statsOnly(statement) \ 300 do { \ 301 } while (0) 302 #endif // _MARKING_STATS_ 303 304 typedef enum { 305 no_verbose = 0, // verbose turned off 306 stats_verbose, // only prints stats at the end of marking 307 low_verbose, // low verbose, mostly per region and per major event 308 medium_verbose, // a bit more detailed than low 309 high_verbose // per object verbose 310 } CMVerboseLevel; 311 312 class YoungList; 313 314 // Root Regions are regions that are not empty at the beginning of a 315 // marking cycle and which we might collect during an evacuation pause 316 // while the cycle is active. Given that, during evacuation pauses, we 317 // do not copy objects that are explicitly marked, what we have to do 318 // for the root regions is to scan them and mark all objects reachable 319 // from them. According to the SATB assumptions, we only need to visit 320 // each object once during marking. So, as long as we finish this scan 321 // before the next evacuation pause, we can copy the objects from the 322 // root regions without having to mark them or do anything else to them. 323 // 324 // Currently, we only support root region scanning once (at the start 325 // of the marking cycle) and the root regions are all the survivor 326 // regions populated during the initial-mark pause. 327 class CMRootRegions VALUE_OBJ_CLASS_SPEC { 328 private: 329 YoungList* _young_list; 330 ConcurrentMark* _cm; 331 332 volatile bool _scan_in_progress; 333 volatile bool _should_abort; 334 HeapRegion* volatile _next_survivor; 335 336 public: 337 CMRootRegions(); 338 // We actually do most of the initialization in this method. 339 void init(G1CollectedHeap* g1h, ConcurrentMark* cm); 340 341 // Reset the claiming / scanning of the root regions. 342 void prepare_for_scan(); 343 344 // Forces get_next() to return NULL so that the iteration aborts early. 345 void abort() { _should_abort = true; } 346 347 // Return true if the CM thread are actively scanning root regions, 348 // false otherwise. 349 bool scan_in_progress() { return _scan_in_progress; } 350 351 // Claim the next root region to scan atomically, or return NULL if 352 // all have been claimed. 353 HeapRegion* claim_next(); 354 355 // Flag that we're done with root region scanning and notify anyone 356 // who's waiting on it. If aborted is false, assume that all regions 357 // have been claimed. 358 void scan_finished(); 359 360 // If CM threads are still scanning root regions, wait until they 361 // are done. Return true if we had to wait, false otherwise. 362 bool wait_until_scan_finished(); 363 }; 364 365 class ConcurrentMarkThread; 366 367 class ConcurrentMark: public CHeapObj<mtGC> { 368 friend class CMMarkStack; 369 friend class ConcurrentMarkThread; 370 friend class CMTask; 371 friend class CMBitMapClosure; 372 friend class CMGlobalObjectClosure; 373 friend class CMRemarkTask; 374 friend class CMConcurrentMarkingTask; 375 friend class G1ParNoteEndTask; 376 friend class CalcLiveObjectsClosure; 377 friend class G1CMRefProcTaskProxy; 378 friend class G1CMRefProcTaskExecutor; 379 friend class G1CMKeepAliveAndDrainClosure; 380 friend class G1CMDrainMarkingStackClosure; 381 382 protected: 383 ConcurrentMarkThread* _cmThread; // The thread doing the work 384 G1CollectedHeap* _g1h; // The heap 385 uint _parallel_marking_threads; // The number of marking 386 // threads we're using 387 uint _max_parallel_marking_threads; // Max number of marking 388 // threads we'll ever use 389 double _sleep_factor; // How much we have to sleep, with 390 // respect to the work we just did, to 391 // meet the marking overhead goal 392 double _marking_task_overhead; // Marking target overhead for 393 // a single task 394 395 // Same as the two above, but for the cleanup task 396 double _cleanup_sleep_factor; 397 double _cleanup_task_overhead; 398 399 FreeRegionList _cleanup_list; 400 401 // Concurrent marking support structures 402 CMBitMap _markBitMap1; 403 CMBitMap _markBitMap2; 404 CMBitMapRO* _prevMarkBitMap; // Completed mark bitmap 405 CMBitMap* _nextMarkBitMap; // Under-construction mark bitmap 406 407 BitMap _region_bm; 408 BitMap _card_bm; 409 410 // Heap bounds 411 HeapWord* _heap_start; 412 HeapWord* _heap_end; 413 414 // Root region tracking and claiming 415 CMRootRegions _root_regions; 416 417 // For gray objects 418 CMMarkStack _markStack; // Grey objects behind global finger 419 HeapWord* volatile _finger; // The global finger, region aligned, 420 // always points to the end of the 421 // last claimed region 422 423 // Marking tasks 424 uint _max_worker_id;// Maximum worker id 425 uint _active_tasks; // Task num currently active 426 CMTask** _tasks; // Task queue array (max_worker_id len) 427 CMTaskQueueSet* _task_queues; // Task queue set 428 ParallelTaskTerminator _terminator; // For termination 429 430 // Two sync barriers that are used to synchronize tasks when an 431 // overflow occurs. The algorithm is the following. All tasks enter 432 // the first one to ensure that they have all stopped manipulating 433 // the global data structures. After they exit it, they re-initialize 434 // their data structures and task 0 re-initializes the global data 435 // structures. Then, they enter the second sync barrier. This 436 // ensure, that no task starts doing work before all data 437 // structures (local and global) have been re-initialized. When they 438 // exit it, they are free to start working again. 439 WorkGangBarrierSync _first_overflow_barrier_sync; 440 WorkGangBarrierSync _second_overflow_barrier_sync; 441 442 // This is set by any task, when an overflow on the global data 443 // structures is detected 444 volatile bool _has_overflown; 445 // True: marking is concurrent, false: we're in remark 446 volatile bool _concurrent; 447 // Set at the end of a Full GC so that marking aborts 448 volatile bool _has_aborted; 449 GCId _aborted_gc_id; 450 451 // Used when remark aborts due to an overflow to indicate that 452 // another concurrent marking phase should start 453 volatile bool _restart_for_overflow; 454 455 // This is true from the very start of concurrent marking until the 456 // point when all the tasks complete their work. It is really used 457 // to determine the points between the end of concurrent marking and 458 // time of remark. 459 volatile bool _concurrent_marking_in_progress; 460 461 // Verbose level 462 CMVerboseLevel _verbose_level; 463 464 // All of these times are in ms 465 NumberSeq _init_times; 466 NumberSeq _remark_times; 467 NumberSeq _remark_mark_times; 468 NumberSeq _remark_weak_ref_times; 469 NumberSeq _cleanup_times; 470 double _total_counting_time; 471 double _total_rs_scrub_time; 472 473 double* _accum_task_vtime; // Accumulated task vtime 474 475 FlexibleWorkGang* _parallel_workers; 476 477 ForceOverflowSettings _force_overflow_conc; 478 ForceOverflowSettings _force_overflow_stw; 479 480 void weakRefsWorkParallelPart(BoolObjectClosure* is_alive, bool purged_classes); 481 void weakRefsWork(bool clear_all_soft_refs); 482 483 void swapMarkBitMaps(); 484 485 // It resets the global marking data structures, as well as the 486 // task local ones; should be called during initial mark. 487 void reset(); 488 489 // Resets all the marking data structures. Called when we have to restart 490 // marking or when marking completes (via set_non_marking_state below). 491 void reset_marking_state(bool clear_overflow = true); 492 493 // We do this after we're done with marking so that the marking data 494 // structures are initialized to a sensible and predictable state. 495 void set_non_marking_state(); 496 497 // Called to indicate how many threads are currently active. 498 void set_concurrency(uint active_tasks); 499 500 // It should be called to indicate which phase we're in (concurrent 501 // mark or remark) and how many threads are currently active. 502 void set_concurrency_and_phase(uint active_tasks, bool concurrent); 503 504 // Prints all gathered CM-related statistics 505 void print_stats(); 506 507 bool cleanup_list_is_empty() { 508 return _cleanup_list.is_empty(); 509 } 510 511 // Accessor methods 512 uint parallel_marking_threads() const { return _parallel_marking_threads; } 513 uint max_parallel_marking_threads() const { return _max_parallel_marking_threads;} 514 double sleep_factor() { return _sleep_factor; } 515 double marking_task_overhead() { return _marking_task_overhead;} 516 double cleanup_sleep_factor() { return _cleanup_sleep_factor; } 517 double cleanup_task_overhead() { return _cleanup_task_overhead;} 518 519 bool use_parallel_marking_threads() const { 520 assert(parallel_marking_threads() <= 521 max_parallel_marking_threads(), "sanity"); 522 assert((_parallel_workers == NULL && parallel_marking_threads() == 0) || 523 parallel_marking_threads() > 0, 524 "parallel workers not set up correctly"); 525 return _parallel_workers != NULL; 526 } 527 528 HeapWord* finger() { return _finger; } 529 bool concurrent() { return _concurrent; } 530 uint active_tasks() { return _active_tasks; } 531 ParallelTaskTerminator* terminator() { return &_terminator; } 532 533 // It claims the next available region to be scanned by a marking 534 // task/thread. It might return NULL if the next region is empty or 535 // we have run out of regions. In the latter case, out_of_regions() 536 // determines whether we've really run out of regions or the task 537 // should call claim_region() again. This might seem a bit 538 // awkward. Originally, the code was written so that claim_region() 539 // either successfully returned with a non-empty region or there 540 // were no more regions to be claimed. The problem with this was 541 // that, in certain circumstances, it iterated over large chunks of 542 // the heap finding only empty regions and, while it was working, it 543 // was preventing the calling task to call its regular clock 544 // method. So, this way, each task will spend very little time in 545 // claim_region() and is allowed to call the regular clock method 546 // frequently. 547 HeapRegion* claim_region(uint worker_id); 548 549 // It determines whether we've run out of regions to scan. Note that 550 // the finger can point past the heap end in case the heap was expanded 551 // to satisfy an allocation without doing a GC. This is fine, because all 552 // objects in those regions will be considered live anyway because of 553 // SATB guarantees (i.e. their TAMS will be equal to bottom). 554 bool out_of_regions() { return _finger >= _heap_end; } 555 556 // Returns the task with the given id 557 CMTask* task(int id) { 558 assert(0 <= id && id < (int) _active_tasks, 559 "task id not within active bounds"); 560 return _tasks[id]; 561 } 562 563 // Returns the task queue with the given id 564 CMTaskQueue* task_queue(int id) { 565 assert(0 <= id && id < (int) _active_tasks, 566 "task queue id not within active bounds"); 567 return (CMTaskQueue*) _task_queues->queue(id); 568 } 569 570 // Returns the task queue set 571 CMTaskQueueSet* task_queues() { return _task_queues; } 572 573 // Access / manipulation of the overflow flag which is set to 574 // indicate that the global stack has overflown 575 bool has_overflown() { return _has_overflown; } 576 void set_has_overflown() { _has_overflown = true; } 577 void clear_has_overflown() { _has_overflown = false; } 578 bool restart_for_overflow() { return _restart_for_overflow; } 579 580 // Methods to enter the two overflow sync barriers 581 void enter_first_sync_barrier(uint worker_id); 582 void enter_second_sync_barrier(uint worker_id); 583 584 ForceOverflowSettings* force_overflow_conc() { 585 return &_force_overflow_conc; 586 } 587 588 ForceOverflowSettings* force_overflow_stw() { 589 return &_force_overflow_stw; 590 } 591 592 ForceOverflowSettings* force_overflow() { 593 if (concurrent()) { 594 return force_overflow_conc(); 595 } else { 596 return force_overflow_stw(); 597 } 598 } 599 600 // Live Data Counting data structures... 601 // These data structures are initialized at the start of 602 // marking. They are written to while marking is active. 603 // They are aggregated during remark; the aggregated values 604 // are then used to populate the _region_bm, _card_bm, and 605 // the total live bytes, which are then subsequently updated 606 // during cleanup. 607 608 // An array of bitmaps (one bit map per task). Each bitmap 609 // is used to record the cards spanned by the live objects 610 // marked by that task/worker. 611 BitMap* _count_card_bitmaps; 612 613 // Used to record the number of marked live bytes 614 // (for each region, by worker thread). 615 size_t** _count_marked_bytes; 616 617 // Card index of the bottom of the G1 heap. Used for biasing indices into 618 // the card bitmaps. 619 intptr_t _heap_bottom_card_num; 620 621 // Set to true when initialization is complete 622 bool _completed_initialization; 623 624 public: 625 // Manipulation of the global mark stack. 626 // Notice that the first mark_stack_push is CAS-based, whereas the 627 // two below are Mutex-based. This is OK since the first one is only 628 // called during evacuation pauses and doesn't compete with the 629 // other two (which are called by the marking tasks during 630 // concurrent marking or remark). 631 bool mark_stack_push(oop p) { 632 _markStack.par_push(p); 633 if (_markStack.overflow()) { 634 set_has_overflown(); 635 return false; 636 } 637 return true; 638 } 639 bool mark_stack_push(oop* arr, int n) { 640 _markStack.par_push_arr(arr, n); 641 if (_markStack.overflow()) { 642 set_has_overflown(); 643 return false; 644 } 645 return true; 646 } 647 void mark_stack_pop(oop* arr, int max, int* n) { 648 _markStack.par_pop_arr(arr, max, n); 649 } 650 size_t mark_stack_size() { return _markStack.size(); } 651 size_t partial_mark_stack_size_target() { return _markStack.maxElems()/3; } 652 bool mark_stack_overflow() { return _markStack.overflow(); } 653 bool mark_stack_empty() { return _markStack.isEmpty(); } 654 655 CMRootRegions* root_regions() { return &_root_regions; } 656 657 bool concurrent_marking_in_progress() { 658 return _concurrent_marking_in_progress; 659 } 660 void set_concurrent_marking_in_progress() { 661 _concurrent_marking_in_progress = true; 662 } 663 void clear_concurrent_marking_in_progress() { 664 _concurrent_marking_in_progress = false; 665 } 666 667 void update_accum_task_vtime(int i, double vtime) { 668 _accum_task_vtime[i] += vtime; 669 } 670 671 double all_task_accum_vtime() { 672 double ret = 0.0; 673 for (uint i = 0; i < _max_worker_id; ++i) 674 ret += _accum_task_vtime[i]; 675 return ret; 676 } 677 678 // Attempts to steal an object from the task queues of other tasks 679 bool try_stealing(uint worker_id, int* hash_seed, oop& obj) { 680 return _task_queues->steal(worker_id, hash_seed, obj); 681 } 682 683 ConcurrentMark(G1CollectedHeap* g1h, ReservedSpace heap_rs); 684 ~ConcurrentMark(); 685 686 ConcurrentMarkThread* cmThread() { return _cmThread; } 687 688 CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; } 689 CMBitMap* nextMarkBitMap() const { return _nextMarkBitMap; } 690 691 // Returns the number of GC threads to be used in a concurrent 692 // phase based on the number of GC threads being used in a STW 693 // phase. 694 uint scale_parallel_threads(uint n_par_threads); 695 696 // Calculates the number of GC threads to be used in a concurrent phase. 697 uint calc_parallel_marking_threads(); 698 699 // The following three are interaction between CM and 700 // G1CollectedHeap 701 702 // This notifies CM that a root during initial-mark needs to be 703 // grayed. It is MT-safe. word_size is the size of the object in 704 // words. It is passed explicitly as sometimes we cannot calculate 705 // it from the given object because it might be in an inconsistent 706 // state (e.g., in to-space and being copied). So the caller is 707 // responsible for dealing with this issue (e.g., get the size from 708 // the from-space image when the to-space image might be 709 // inconsistent) and always passing the size. hr is the region that 710 // contains the object and it's passed optionally from callers who 711 // might already have it (no point in recalculating it). 712 inline void grayRoot(oop obj, size_t word_size, 713 uint worker_id, HeapRegion* hr = NULL); 714 715 // It iterates over the heap and for each object it comes across it 716 // will dump the contents of its reference fields, as well as 717 // liveness information for the object and its referents. The dump 718 // will be written to a file with the following name: 719 // G1PrintReachableBaseFile + "." + str. 720 // vo decides whether the prev (vo == UsePrevMarking), the next 721 // (vo == UseNextMarking) marking information, or the mark word 722 // (vo == UseMarkWord) will be used to determine the liveness of 723 // each object / referent. 724 // If all is true, all objects in the heap will be dumped, otherwise 725 // only the live ones. In the dump the following symbols / breviations 726 // are used: 727 // M : an explicitly live object (its bitmap bit is set) 728 // > : an implicitly live object (over tams) 729 // O : an object outside the G1 heap (typically: in the perm gen) 730 // NOT : a reference field whose referent is not live 731 // AND MARKED : indicates that an object is both explicitly and 732 // implicitly live (it should be one or the other, not both) 733 void print_reachable(const char* str, 734 VerifyOption vo, bool all) PRODUCT_RETURN; 735 736 // Clear the next marking bitmap (will be called concurrently). 737 void clearNextBitmap(); 738 739 // Return whether the next mark bitmap has no marks set. 740 bool nextMarkBitmapIsClear(); 741 742 // These two do the work that needs to be done before and after the 743 // initial root checkpoint. Since this checkpoint can be done at two 744 // different points (i.e. an explicit pause or piggy-backed on a 745 // young collection), then it's nice to be able to easily share the 746 // pre/post code. It might be the case that we can put everything in 747 // the post method. TP 748 void checkpointRootsInitialPre(); 749 void checkpointRootsInitialPost(); 750 751 // Scan all the root regions and mark everything reachable from 752 // them. 753 void scanRootRegions(); 754 755 // Scan a single root region and mark everything reachable from it. 756 void scanRootRegion(HeapRegion* hr, uint worker_id); 757 758 // Do concurrent phase of marking, to a tentative transitive closure. 759 void markFromRoots(); 760 761 void checkpointRootsFinal(bool clear_all_soft_refs); 762 void checkpointRootsFinalWork(); 763 void cleanup(); 764 void completeCleanup(); 765 766 // Mark in the previous bitmap. NB: this is usually read-only, so use 767 // this carefully! 768 inline void markPrev(oop p); 769 770 // Clears marks for all objects in the given range, for the prev, 771 // next, or both bitmaps. NB: the previous bitmap is usually 772 // read-only, so use this carefully! 773 void clearRangePrevBitmap(MemRegion mr); 774 void clearRangeNextBitmap(MemRegion mr); 775 void clearRangeBothBitmaps(MemRegion mr); 776 777 // Notify data structures that a GC has started. 778 void note_start_of_gc() { 779 _markStack.note_start_of_gc(); 780 } 781 782 // Notify data structures that a GC is finished. 783 void note_end_of_gc() { 784 _markStack.note_end_of_gc(); 785 } 786 787 // Verify that there are no CSet oops on the stacks (taskqueues / 788 // global mark stack), enqueued SATB buffers, per-thread SATB 789 // buffers, and fingers (global / per-task). The boolean parameters 790 // decide which of the above data structures to verify. If marking 791 // is not in progress, it's a no-op. 792 void verify_no_cset_oops(bool verify_stacks, 793 bool verify_enqueued_buffers, 794 bool verify_thread_buffers, 795 bool verify_fingers) PRODUCT_RETURN; 796 797 // It is called at the end of an evacuation pause during marking so 798 // that CM is notified of where the new end of the heap is. It 799 // doesn't do anything if concurrent_marking_in_progress() is false, 800 // unless the force parameter is true. 801 void update_g1_committed(bool force = false); 802 803 bool isMarked(oop p) const { 804 assert(p != NULL && p->is_oop(), "expected an oop"); 805 HeapWord* addr = (HeapWord*)p; 806 assert(addr >= _nextMarkBitMap->startWord() || 807 addr < _nextMarkBitMap->endWord(), "in a region"); 808 809 return _nextMarkBitMap->isMarked(addr); 810 } 811 812 inline bool not_yet_marked(oop p) const; 813 814 // XXX Debug code 815 bool containing_card_is_marked(void* p); 816 bool containing_cards_are_marked(void* start, void* last); 817 818 bool isPrevMarked(oop p) const { 819 assert(p != NULL && p->is_oop(), "expected an oop"); 820 HeapWord* addr = (HeapWord*)p; 821 assert(addr >= _prevMarkBitMap->startWord() || 822 addr < _prevMarkBitMap->endWord(), "in a region"); 823 824 return _prevMarkBitMap->isMarked(addr); 825 } 826 827 inline bool do_yield_check(uint worker_i = 0); 828 829 // Called to abort the marking cycle after a Full GC takes place. 830 void abort(); 831 832 bool has_aborted() { return _has_aborted; } 833 834 const GCId& concurrent_gc_id(); 835 836 // This prints the global/local fingers. It is used for debugging. 837 NOT_PRODUCT(void print_finger();) 838 839 void print_summary_info(); 840 841 void print_worker_threads_on(outputStream* st) const; 842 843 void print_on_error(outputStream* st) const; 844 845 // The following indicate whether a given verbose level has been 846 // set. Notice that anything above stats is conditional to 847 // _MARKING_VERBOSE_ having been set to 1 848 bool verbose_stats() { 849 return _verbose_level >= stats_verbose; 850 } 851 bool verbose_low() { 852 return _MARKING_VERBOSE_ && _verbose_level >= low_verbose; 853 } 854 bool verbose_medium() { 855 return _MARKING_VERBOSE_ && _verbose_level >= medium_verbose; 856 } 857 bool verbose_high() { 858 return _MARKING_VERBOSE_ && _verbose_level >= high_verbose; 859 } 860 861 // Liveness counting 862 863 // Utility routine to set an exclusive range of cards on the given 864 // card liveness bitmap 865 inline void set_card_bitmap_range(BitMap* card_bm, 866 BitMap::idx_t start_idx, 867 BitMap::idx_t end_idx, 868 bool is_par); 869 870 // Returns the card number of the bottom of the G1 heap. 871 // Used in biasing indices into accounting card bitmaps. 872 intptr_t heap_bottom_card_num() const { 873 return _heap_bottom_card_num; 874 } 875 876 // Returns the card bitmap for a given task or worker id. 877 BitMap* count_card_bitmap_for(uint worker_id) { 878 assert(0 <= worker_id && worker_id < _max_worker_id, "oob"); 879 assert(_count_card_bitmaps != NULL, "uninitialized"); 880 BitMap* task_card_bm = &_count_card_bitmaps[worker_id]; 881 assert(task_card_bm->size() == _card_bm.size(), "size mismatch"); 882 return task_card_bm; 883 } 884 885 // Returns the array containing the marked bytes for each region, 886 // for the given worker or task id. 887 size_t* count_marked_bytes_array_for(uint worker_id) { 888 assert(0 <= worker_id && worker_id < _max_worker_id, "oob"); 889 assert(_count_marked_bytes != NULL, "uninitialized"); 890 size_t* marked_bytes_array = _count_marked_bytes[worker_id]; 891 assert(marked_bytes_array != NULL, "uninitialized"); 892 return marked_bytes_array; 893 } 894 895 // Returns the index in the liveness accounting card table bitmap 896 // for the given address 897 inline BitMap::idx_t card_bitmap_index_for(HeapWord* addr); 898 899 // Counts the size of the given memory region in the the given 900 // marked_bytes array slot for the given HeapRegion. 901 // Sets the bits in the given card bitmap that are associated with the 902 // cards that are spanned by the memory region. 903 inline void count_region(MemRegion mr, HeapRegion* hr, 904 size_t* marked_bytes_array, 905 BitMap* task_card_bm); 906 907 // Counts the given memory region in the task/worker counting 908 // data structures for the given worker id. 909 inline void count_region(MemRegion mr, HeapRegion* hr, uint worker_id); 910 911 // Counts the given memory region in the task/worker counting 912 // data structures for the given worker id. 913 inline void count_region(MemRegion mr, uint worker_id); 914 915 // Counts the given object in the given task/worker counting 916 // data structures. 917 inline void count_object(oop obj, HeapRegion* hr, 918 size_t* marked_bytes_array, 919 BitMap* task_card_bm); 920 921 // Counts the given object in the task/worker counting data 922 // structures for the given worker id. 923 inline void count_object(oop obj, HeapRegion* hr, uint worker_id); 924 925 // Attempts to mark the given object and, if successful, counts 926 // the object in the given task/worker counting structures. 927 inline bool par_mark_and_count(oop obj, HeapRegion* hr, 928 size_t* marked_bytes_array, 929 BitMap* task_card_bm); 930 931 // Attempts to mark the given object and, if successful, counts 932 // the object in the task/worker counting structures for the 933 // given worker id. 934 inline bool par_mark_and_count(oop obj, size_t word_size, 935 HeapRegion* hr, uint worker_id); 936 937 // Attempts to mark the given object and, if successful, counts 938 // the object in the task/worker counting structures for the 939 // given worker id. 940 inline bool par_mark_and_count(oop obj, HeapRegion* hr, uint worker_id); 941 942 // Similar to the above routine but we don't know the heap region that 943 // contains the object to be marked/counted, which this routine looks up. 944 inline bool par_mark_and_count(oop obj, uint worker_id); 945 946 // Similar to the above routine but there are times when we cannot 947 // safely calculate the size of obj due to races and we, therefore, 948 // pass the size in as a parameter. It is the caller's responsibility 949 // to ensure that the size passed in for obj is valid. 950 inline bool par_mark_and_count(oop obj, size_t word_size, uint worker_id); 951 952 // Unconditionally mark the given object, and unconditionally count 953 // the object in the counting structures for worker id 0. 954 // Should *not* be called from parallel code. 955 inline bool mark_and_count(oop obj, HeapRegion* hr); 956 957 // Similar to the above routine but we don't know the heap region that 958 // contains the object to be marked/counted, which this routine looks up. 959 // Should *not* be called from parallel code. 960 inline bool mark_and_count(oop obj); 961 962 // Returns true if initialization was successfully completed. 963 bool completed_initialization() const { 964 return _completed_initialization; 965 } 966 967 protected: 968 // Clear all the per-task bitmaps and arrays used to store the 969 // counting data. 970 void clear_all_count_data(); 971 972 // Aggregates the counting data for each worker/task 973 // that was constructed while marking. Also sets 974 // the amount of marked bytes for each region and 975 // the top at concurrent mark count. 976 void aggregate_count_data(); 977 978 // Verification routine 979 void verify_count_data(); 980 }; 981 982 // A class representing a marking task. 983 class CMTask : public TerminatorTerminator { 984 private: 985 enum PrivateConstants { 986 // the regular clock call is called once the scanned words reaches 987 // this limit 988 words_scanned_period = 12*1024, 989 // the regular clock call is called once the number of visited 990 // references reaches this limit 991 refs_reached_period = 384, 992 // initial value for the hash seed, used in the work stealing code 993 init_hash_seed = 17, 994 // how many entries will be transferred between global stack and 995 // local queues 996 global_stack_transfer_size = 16 997 }; 998 999 uint _worker_id; 1000 G1CollectedHeap* _g1h; 1001 ConcurrentMark* _cm; 1002 CMBitMap* _nextMarkBitMap; 1003 // the task queue of this task 1004 CMTaskQueue* _task_queue; 1005 private: 1006 // the task queue set---needed for stealing 1007 CMTaskQueueSet* _task_queues; 1008 // indicates whether the task has been claimed---this is only for 1009 // debugging purposes 1010 bool _claimed; 1011 1012 // number of calls to this task 1013 int _calls; 1014 1015 // when the virtual timer reaches this time, the marking step should 1016 // exit 1017 double _time_target_ms; 1018 // the start time of the current marking step 1019 double _start_time_ms; 1020 1021 // the oop closure used for iterations over oops 1022 G1CMOopClosure* _cm_oop_closure; 1023 1024 // the region this task is scanning, NULL if we're not scanning any 1025 HeapRegion* _curr_region; 1026 // the local finger of this task, NULL if we're not scanning a region 1027 HeapWord* _finger; 1028 // limit of the region this task is scanning, NULL if we're not scanning one 1029 HeapWord* _region_limit; 1030 1031 // the number of words this task has scanned 1032 size_t _words_scanned; 1033 // When _words_scanned reaches this limit, the regular clock is 1034 // called. Notice that this might be decreased under certain 1035 // circumstances (i.e. when we believe that we did an expensive 1036 // operation). 1037 size_t _words_scanned_limit; 1038 // the initial value of _words_scanned_limit (i.e. what it was 1039 // before it was decreased). 1040 size_t _real_words_scanned_limit; 1041 1042 // the number of references this task has visited 1043 size_t _refs_reached; 1044 // When _refs_reached reaches this limit, the regular clock is 1045 // called. Notice this this might be decreased under certain 1046 // circumstances (i.e. when we believe that we did an expensive 1047 // operation). 1048 size_t _refs_reached_limit; 1049 // the initial value of _refs_reached_limit (i.e. what it was before 1050 // it was decreased). 1051 size_t _real_refs_reached_limit; 1052 1053 // used by the work stealing stuff 1054 int _hash_seed; 1055 // if this is true, then the task has aborted for some reason 1056 bool _has_aborted; 1057 // set when the task aborts because it has met its time quota 1058 bool _has_timed_out; 1059 // true when we're draining SATB buffers; this avoids the task 1060 // aborting due to SATB buffers being available (as we're already 1061 // dealing with them) 1062 bool _draining_satb_buffers; 1063 1064 // number sequence of past step times 1065 NumberSeq _step_times_ms; 1066 // elapsed time of this task 1067 double _elapsed_time_ms; 1068 // termination time of this task 1069 double _termination_time_ms; 1070 // when this task got into the termination protocol 1071 double _termination_start_time_ms; 1072 1073 // true when the task is during a concurrent phase, false when it is 1074 // in the remark phase (so, in the latter case, we do not have to 1075 // check all the things that we have to check during the concurrent 1076 // phase, i.e. SATB buffer availability...) 1077 bool _concurrent; 1078 1079 TruncatedSeq _marking_step_diffs_ms; 1080 1081 // Counting data structures. Embedding the task's marked_bytes_array 1082 // and card bitmap into the actual task saves having to go through 1083 // the ConcurrentMark object. 1084 size_t* _marked_bytes_array; 1085 BitMap* _card_bm; 1086 1087 // LOTS of statistics related with this task 1088 #if _MARKING_STATS_ 1089 NumberSeq _all_clock_intervals_ms; 1090 double _interval_start_time_ms; 1091 1092 int _aborted; 1093 int _aborted_overflow; 1094 int _aborted_cm_aborted; 1095 int _aborted_yield; 1096 int _aborted_timed_out; 1097 int _aborted_satb; 1098 int _aborted_termination; 1099 1100 int _steal_attempts; 1101 int _steals; 1102 1103 int _clock_due_to_marking; 1104 int _clock_due_to_scanning; 1105 1106 int _local_pushes; 1107 int _local_pops; 1108 int _local_max_size; 1109 int _objs_scanned; 1110 1111 int _global_pushes; 1112 int _global_pops; 1113 int _global_max_size; 1114 1115 int _global_transfers_to; 1116 int _global_transfers_from; 1117 1118 int _regions_claimed; 1119 int _objs_found_on_bitmap; 1120 1121 int _satb_buffers_processed; 1122 #endif // _MARKING_STATS_ 1123 1124 // it updates the local fields after this task has claimed 1125 // a new region to scan 1126 void setup_for_region(HeapRegion* hr); 1127 // it brings up-to-date the limit of the region 1128 void update_region_limit(); 1129 1130 // called when either the words scanned or the refs visited limit 1131 // has been reached 1132 void reached_limit(); 1133 // recalculates the words scanned and refs visited limits 1134 void recalculate_limits(); 1135 // decreases the words scanned and refs visited limits when we reach 1136 // an expensive operation 1137 void decrease_limits(); 1138 // it checks whether the words scanned or refs visited reached their 1139 // respective limit and calls reached_limit() if they have 1140 void check_limits() { 1141 if (_words_scanned >= _words_scanned_limit || 1142 _refs_reached >= _refs_reached_limit) { 1143 reached_limit(); 1144 } 1145 } 1146 // this is supposed to be called regularly during a marking step as 1147 // it checks a bunch of conditions that might cause the marking step 1148 // to abort 1149 void regular_clock_call(); 1150 bool concurrent() { return _concurrent; } 1151 1152 public: 1153 // It resets the task; it should be called right at the beginning of 1154 // a marking phase. 1155 void reset(CMBitMap* _nextMarkBitMap); 1156 // it clears all the fields that correspond to a claimed region. 1157 void clear_region_fields(); 1158 1159 void set_concurrent(bool concurrent) { _concurrent = concurrent; } 1160 1161 // The main method of this class which performs a marking step 1162 // trying not to exceed the given duration. However, it might exit 1163 // prematurely, according to some conditions (i.e. SATB buffers are 1164 // available for processing). 1165 void do_marking_step(double target_ms, 1166 bool do_termination, 1167 bool is_serial); 1168 1169 // These two calls start and stop the timer 1170 void record_start_time() { 1171 _elapsed_time_ms = os::elapsedTime() * 1000.0; 1172 } 1173 void record_end_time() { 1174 _elapsed_time_ms = os::elapsedTime() * 1000.0 - _elapsed_time_ms; 1175 } 1176 1177 // returns the worker ID associated with this task. 1178 uint worker_id() { return _worker_id; } 1179 1180 // From TerminatorTerminator. It determines whether this task should 1181 // exit the termination protocol after it's entered it. 1182 virtual bool should_exit_termination(); 1183 1184 // Resets the local region fields after a task has finished scanning a 1185 // region; or when they have become stale as a result of the region 1186 // being evacuated. 1187 void giveup_current_region(); 1188 1189 HeapWord* finger() { return _finger; } 1190 1191 bool has_aborted() { return _has_aborted; } 1192 void set_has_aborted() { _has_aborted = true; } 1193 void clear_has_aborted() { _has_aborted = false; } 1194 bool has_timed_out() { return _has_timed_out; } 1195 bool claimed() { return _claimed; } 1196 1197 void set_cm_oop_closure(G1CMOopClosure* cm_oop_closure); 1198 1199 // It grays the object by marking it and, if necessary, pushing it 1200 // on the local queue 1201 inline void deal_with_reference(oop obj); 1202 1203 // It scans an object and visits its children. 1204 void scan_object(oop obj); 1205 1206 // It pushes an object on the local queue. 1207 inline void push(oop obj); 1208 1209 // These two move entries to/from the global stack. 1210 void move_entries_to_global_stack(); 1211 void get_entries_from_global_stack(); 1212 1213 // It pops and scans objects from the local queue. If partially is 1214 // true, then it stops when the queue size is of a given limit. If 1215 // partially is false, then it stops when the queue is empty. 1216 void drain_local_queue(bool partially); 1217 // It moves entries from the global stack to the local queue and 1218 // drains the local queue. If partially is true, then it stops when 1219 // both the global stack and the local queue reach a given size. If 1220 // partially if false, it tries to empty them totally. 1221 void drain_global_stack(bool partially); 1222 // It keeps picking SATB buffers and processing them until no SATB 1223 // buffers are available. 1224 void drain_satb_buffers(); 1225 1226 // moves the local finger to a new location 1227 inline void move_finger_to(HeapWord* new_finger) { 1228 assert(new_finger >= _finger && new_finger < _region_limit, "invariant"); 1229 _finger = new_finger; 1230 } 1231 1232 CMTask(uint worker_id, ConcurrentMark *cm, 1233 size_t* marked_bytes, BitMap* card_bm, 1234 CMTaskQueue* task_queue, CMTaskQueueSet* task_queues); 1235 1236 // it prints statistics associated with this task 1237 void print_stats(); 1238 1239 #if _MARKING_STATS_ 1240 void increase_objs_found_on_bitmap() { ++_objs_found_on_bitmap; } 1241 #endif // _MARKING_STATS_ 1242 }; 1243 1244 // Class that's used to to print out per-region liveness 1245 // information. It's currently used at the end of marking and also 1246 // after we sort the old regions at the end of the cleanup operation. 1247 class G1PrintRegionLivenessInfoClosure: public HeapRegionClosure { 1248 private: 1249 outputStream* _out; 1250 1251 // Accumulators for these values. 1252 size_t _total_used_bytes; 1253 size_t _total_capacity_bytes; 1254 size_t _total_prev_live_bytes; 1255 size_t _total_next_live_bytes; 1256 1257 // These are set up when we come across a "stars humongous" region 1258 // (as this is where most of this information is stored, not in the 1259 // subsequent "continues humongous" regions). After that, for every 1260 // region in a given humongous region series we deduce the right 1261 // values for it by simply subtracting the appropriate amount from 1262 // these fields. All these values should reach 0 after we've visited 1263 // the last region in the series. 1264 size_t _hum_used_bytes; 1265 size_t _hum_capacity_bytes; 1266 size_t _hum_prev_live_bytes; 1267 size_t _hum_next_live_bytes; 1268 1269 // Accumulator for the remembered set size 1270 size_t _total_remset_bytes; 1271 1272 // Accumulator for strong code roots memory size 1273 size_t _total_strong_code_roots_bytes; 1274 1275 static double perc(size_t val, size_t total) { 1276 if (total == 0) { 1277 return 0.0; 1278 } else { 1279 return 100.0 * ((double) val / (double) total); 1280 } 1281 } 1282 1283 static double bytes_to_mb(size_t val) { 1284 return (double) val / (double) M; 1285 } 1286 1287 // See the .cpp file. 1288 size_t get_hum_bytes(size_t* hum_bytes); 1289 void get_hum_bytes(size_t* used_bytes, size_t* capacity_bytes, 1290 size_t* prev_live_bytes, size_t* next_live_bytes); 1291 1292 public: 1293 // The header and footer are printed in the constructor and 1294 // destructor respectively. 1295 G1PrintRegionLivenessInfoClosure(outputStream* out, const char* phase_name); 1296 virtual bool doHeapRegion(HeapRegion* r); 1297 ~G1PrintRegionLivenessInfoClosure(); 1298 }; 1299 1300 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_HPP