rev 7793 : 8073315: Enable gcc -Wtype-limits and fix upcoming issues.

   1 /*
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   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).
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  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/g1/g1RegionToSpaceMapper.hpp"
  31 #include "gc_implementation/shared/gcId.hpp"
  32 #include "utilities/taskqueue.hpp"
  33 
  34 class G1CollectedHeap;
  35 class CMBitMap;
  36 class CMTask;
  37 typedef GenericTaskQueue<oop, mtGC>            CMTaskQueue;
  38 typedef GenericTaskQueueSet<CMTaskQueue, mtGC> CMTaskQueueSet;
  39 
  40 // Closure used by CM during concurrent reference discovery
  41 // and reference processing (during remarking) to determine
  42 // if a particular object is alive. It is primarily used
  43 // to determine if referents of discovered reference objects
  44 // are alive. An instance is also embedded into the
  45 // reference processor as the _is_alive_non_header field
  46 class G1CMIsAliveClosure: public BoolObjectClosure {
  47   G1CollectedHeap* _g1;
  48  public:
  49   G1CMIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) { }
  50 
  51   bool do_object_b(oop obj);
  52 };
  53 
  54 // A generic CM bit map.  This is essentially a wrapper around the BitMap
  55 // class, with one bit per (1<<_shifter) HeapWords.
  56 
  57 class CMBitMapRO VALUE_OBJ_CLASS_SPEC {
  58  protected:
  59   HeapWord* _bmStartWord;      // base address of range covered by map
  60   size_t    _bmWordSize;       // map size (in #HeapWords covered)
  61   const int _shifter;          // map to char or bit
  62   BitMap    _bm;               // the bit map itself
  63 
  64  public:
  65   // constructor
  66   CMBitMapRO(int shifter);
  67 
  68   enum { do_yield = true };
  69 
  70   // inquiries
  71   HeapWord* startWord()   const { return _bmStartWord; }
  72   size_t    sizeInWords() const { return _bmWordSize;  }
  73   // the following is one past the last word in space
  74   HeapWord* endWord()     const { return _bmStartWord + _bmWordSize; }
  75 
  76   // read marks
  77 
  78   bool isMarked(HeapWord* addr) const {
  79     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
  80            "outside underlying space?");
  81     return _bm.at(heapWordToOffset(addr));
  82   }
  83 
  84   // iteration
  85   inline bool iterate(BitMapClosure* cl, MemRegion mr);
  86   inline bool iterate(BitMapClosure* cl);
  87 
  88   // Return the address corresponding to the next marked bit at or after
  89   // "addr", and before "limit", if "limit" is non-NULL.  If there is no
  90   // such bit, returns "limit" if that is non-NULL, or else "endWord()".
  91   HeapWord* getNextMarkedWordAddress(const HeapWord* addr,
  92                                      const HeapWord* limit = NULL) const;
  93   // Return the address corresponding to the next unmarked bit at or after
  94   // "addr", and before "limit", if "limit" is non-NULL.  If there is no
  95   // such bit, returns "limit" if that is non-NULL, or else "endWord()".
  96   HeapWord* getNextUnmarkedWordAddress(const HeapWord* addr,
  97                                        const HeapWord* limit = NULL) const;
  98 
  99   // conversion utilities
 100   HeapWord* offsetToHeapWord(size_t offset) const {
 101     return _bmStartWord + (offset << _shifter);
 102   }
 103   size_t heapWordToOffset(const HeapWord* addr) const {
 104     return pointer_delta(addr, _bmStartWord) >> _shifter;
 105   }
 106   int heapWordDiffToOffsetDiff(size_t diff) const;
 107 
 108   // The argument addr should be the start address of a valid object
 109   HeapWord* nextObject(HeapWord* addr) {
 110     oop obj = (oop) addr;
 111     HeapWord* res =  addr + obj->size();
 112     assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity");
 113     return res;
 114   }
 115 
 116   void print_on_error(outputStream* st, const char* prefix) const;
 117 
 118   // debugging
 119   NOT_PRODUCT(bool covers(MemRegion rs) const;)
 120 };
 121 
 122 class CMBitMapMappingChangedListener : public G1MappingChangedListener {
 123  private:
 124   CMBitMap* _bm;
 125  public:
 126   CMBitMapMappingChangedListener() : _bm(NULL) {}
 127 
 128   void set_bitmap(CMBitMap* bm) { _bm = bm; }
 129 
 130   virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
 131 };
 132 
 133 class CMBitMap : public CMBitMapRO {
 134  private:
 135   CMBitMapMappingChangedListener _listener;
 136 
 137  public:
 138   static size_t compute_size(size_t heap_size);
 139   // Returns the amount of bytes on the heap between two marks in the bitmap.
 140   static size_t mark_distance();
 141 
 142   CMBitMap() : CMBitMapRO(LogMinObjAlignment), _listener() { _listener.set_bitmap(this); }
 143 
 144   // Initializes the underlying BitMap to cover the given area.
 145   void initialize(MemRegion heap, G1RegionToSpaceMapper* storage);
 146 
 147   // Write marks.
 148   inline void mark(HeapWord* addr);
 149   inline void clear(HeapWord* addr);
 150   inline bool parMark(HeapWord* addr);
 151   inline bool parClear(HeapWord* addr);
 152 
 153   void markRange(MemRegion mr);
 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   // Clear the whole mark bitmap.
 166   void clearAll();
 167 };
 168 
 169 // Represents a marking stack used by ConcurrentMarking in the G1 collector.
 170 class CMMarkStack VALUE_OBJ_CLASS_SPEC {
 171   VirtualSpace _virtual_space;   // Underlying backing store for actual stack
 172   ConcurrentMark* _cm;
 173   oop* _base;        // bottom of stack
 174   jint _index;       // one more than last occupied index
 175   jint _capacity;    // max #elements
 176   jint _saved_index; // value of _index saved at start of GC
 177   NOT_PRODUCT(jint _max_depth;)   // max depth plumbed during run
 178 
 179   bool  _overflow;
 180   bool  _should_expand;
 181   DEBUG_ONLY(bool _drain_in_progress;)
 182   DEBUG_ONLY(bool _drain_in_progress_yields;)
 183 
 184  public:
 185   CMMarkStack(ConcurrentMark* cm);
 186   ~CMMarkStack();
 187 
 188 #ifndef PRODUCT
 189   jint max_depth() const {
 190     return _max_depth;
 191   }
 192 #endif
 193 
 194   bool allocate(size_t capacity);
 195 
 196   oop pop() {
 197     if (!isEmpty()) {
 198       return _base[--_index] ;
 199     }
 200     return NULL;
 201   }
 202 
 203   // If overflow happens, don't do the push, and record the overflow.
 204   // *Requires* that "ptr" is already marked.
 205   void push(oop ptr) {
 206     if (isFull()) {
 207       // Record overflow.
 208       _overflow = true;
 209       return;
 210     } else {
 211       _base[_index++] = ptr;
 212       NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index));
 213     }
 214   }
 215   // Non-block impl.  Note: concurrency is allowed only with other
 216   // "par_push" operations, not with "pop" or "drain".  We would need
 217   // parallel versions of them if such concurrency was desired.
 218   void par_push(oop ptr);
 219 
 220   // Pushes the first "n" elements of "ptr_arr" on the stack.
 221   // Non-block impl.  Note: concurrency is allowed only with other
 222   // "par_adjoin_arr" or "push" operations, not with "pop" or "drain".
 223   void par_adjoin_arr(oop* ptr_arr, int n);
 224 
 225   // Pushes the first "n" elements of "ptr_arr" on the stack.
 226   // Locking impl: concurrency is allowed only with
 227   // "par_push_arr" and/or "par_pop_arr" operations, which use the same
 228   // locking strategy.
 229   void par_push_arr(oop* ptr_arr, int n);
 230 
 231   // If returns false, the array was empty.  Otherwise, removes up to "max"
 232   // elements from the stack, and transfers them to "ptr_arr" in an
 233   // unspecified order.  The actual number transferred is given in "n" ("n
 234   // == 0" is deliberately redundant with the return value.)  Locking impl:
 235   // concurrency is allowed only with "par_push_arr" and/or "par_pop_arr"
 236   // operations, which use the same locking strategy.
 237   bool par_pop_arr(oop* ptr_arr, int max, int* n);
 238 
 239   // Drain the mark stack, applying the given closure to all fields of
 240   // objects on the stack.  (That is, continue until the stack is empty,
 241   // even if closure applications add entries to the stack.)  The "bm"
 242   // argument, if non-null, may be used to verify that only marked objects
 243   // are on the mark stack.  If "yield_after" is "true", then the
 244   // concurrent marker performing the drain offers to yield after
 245   // processing each object.  If a yield occurs, stops the drain operation
 246   // and returns false.  Otherwise, returns true.
 247   template<class OopClosureClass>
 248   bool drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after = false);
 249 
 250   bool isEmpty()    { return _index == 0; }
 251   bool isFull()     { return _index == _capacity; }
 252   int  maxElems()   { return _capacity; }
 253 
 254   bool overflow() { return _overflow; }
 255   void clear_overflow() { _overflow = false; }
 256 
 257   bool should_expand() const { return _should_expand; }
 258   void set_should_expand();
 259 
 260   // Expand the stack, typically in response to an overflow condition
 261   void expand();
 262 
 263   int  size() { return _index; }
 264 
 265   void setEmpty()   { _index = 0; clear_overflow(); }
 266 
 267   // Record the current index.
 268   void note_start_of_gc();
 269 
 270   // Make sure that we have not added any entries to the stack during GC.
 271   void note_end_of_gc();
 272 
 273   // iterate over the oops in the mark stack, up to the bound recorded via
 274   // the call above.
 275   void oops_do(OopClosure* f);
 276 };
 277 
 278 class ForceOverflowSettings VALUE_OBJ_CLASS_SPEC {
 279 private:
 280 #ifndef PRODUCT
 281   uintx _num_remaining;
 282   bool _force;
 283 #endif // !defined(PRODUCT)
 284 
 285 public:
 286   void init() PRODUCT_RETURN;
 287   void update() PRODUCT_RETURN;
 288   bool should_force() PRODUCT_RETURN_( return false; );
 289 };
 290 
 291 // this will enable a variety of different statistics per GC task
 292 #define _MARKING_STATS_       0
 293 // this will enable the higher verbose levels
 294 #define _MARKING_VERBOSE_     0
 295 
 296 #if _MARKING_STATS_
 297 #define statsOnly(statement)  \
 298 do {                          \
 299   statement ;                 \
 300 } while (0)
 301 #else // _MARKING_STATS_
 302 #define statsOnly(statement)  \
 303 do {                          \
 304 } while (0)
 305 #endif // _MARKING_STATS_
 306 
 307 typedef enum {
 308   no_verbose  = 0,   // verbose turned off
 309   stats_verbose,     // only prints stats at the end of marking
 310   low_verbose,       // low verbose, mostly per region and per major event
 311   medium_verbose,    // a bit more detailed than low
 312   high_verbose       // per object verbose
 313 } CMVerboseLevel;
 314 
 315 class YoungList;
 316 
 317 // Root Regions are regions that are not empty at the beginning of a
 318 // marking cycle and which we might collect during an evacuation pause
 319 // while the cycle is active. Given that, during evacuation pauses, we
 320 // do not copy objects that are explicitly marked, what we have to do
 321 // for the root regions is to scan them and mark all objects reachable
 322 // from them. According to the SATB assumptions, we only need to visit
 323 // each object once during marking. So, as long as we finish this scan
 324 // before the next evacuation pause, we can copy the objects from the
 325 // root regions without having to mark them or do anything else to them.
 326 //
 327 // Currently, we only support root region scanning once (at the start
 328 // of the marking cycle) and the root regions are all the survivor
 329 // regions populated during the initial-mark pause.
 330 class CMRootRegions VALUE_OBJ_CLASS_SPEC {
 331 private:
 332   YoungList*           _young_list;
 333   ConcurrentMark*      _cm;
 334 
 335   volatile bool        _scan_in_progress;
 336   volatile bool        _should_abort;
 337   HeapRegion* volatile _next_survivor;
 338 
 339 public:
 340   CMRootRegions();
 341   // We actually do most of the initialization in this method.
 342   void init(G1CollectedHeap* g1h, ConcurrentMark* cm);
 343 
 344   // Reset the claiming / scanning of the root regions.
 345   void prepare_for_scan();
 346 
 347   // Forces get_next() to return NULL so that the iteration aborts early.
 348   void abort() { _should_abort = true; }
 349 
 350   // Return true if the CM thread are actively scanning root regions,
 351   // false otherwise.
 352   bool scan_in_progress() { return _scan_in_progress; }
 353 
 354   // Claim the next root region to scan atomically, or return NULL if
 355   // all have been claimed.
 356   HeapRegion* claim_next();
 357 
 358   // Flag that we're done with root region scanning and notify anyone
 359   // who's waiting on it. If aborted is false, assume that all regions
 360   // have been claimed.
 361   void scan_finished();
 362 
 363   // If CM threads are still scanning root regions, wait until they
 364   // are done. Return true if we had to wait, false otherwise.
 365   bool wait_until_scan_finished();
 366 };
 367 
 368 class ConcurrentMarkThread;
 369 
 370 class ConcurrentMark: public CHeapObj<mtGC> {
 371   friend class CMMarkStack;
 372   friend class ConcurrentMarkThread;
 373   friend class CMTask;
 374   friend class CMBitMapClosure;
 375   friend class CMGlobalObjectClosure;
 376   friend class CMRemarkTask;
 377   friend class CMConcurrentMarkingTask;
 378   friend class G1ParNoteEndTask;
 379   friend class CalcLiveObjectsClosure;
 380   friend class G1CMRefProcTaskProxy;
 381   friend class G1CMRefProcTaskExecutor;
 382   friend class G1CMKeepAliveAndDrainClosure;
 383   friend class G1CMDrainMarkingStackClosure;
 384 
 385 protected:
 386   ConcurrentMarkThread* _cmThread;   // The thread doing the work
 387   G1CollectedHeap*      _g1h;        // The heap
 388   uint                  _parallel_marking_threads; // The number of marking
 389                                                    // threads we're using
 390   uint                  _max_parallel_marking_threads; // Max number of marking
 391                                                        // threads we'll ever use
 392   double                _sleep_factor; // How much we have to sleep, with
 393                                        // respect to the work we just did, to
 394                                        // meet the marking overhead goal
 395   double                _marking_task_overhead; // Marking target overhead for
 396                                                 // a single task
 397 
 398   // Same as the two above, but for the cleanup task
 399   double                _cleanup_sleep_factor;
 400   double                _cleanup_task_overhead;
 401 
 402   FreeRegionList        _cleanup_list;
 403 
 404   // Concurrent marking support structures
 405   CMBitMap                _markBitMap1;
 406   CMBitMap                _markBitMap2;
 407   CMBitMapRO*             _prevMarkBitMap; // Completed mark bitmap
 408   CMBitMap*               _nextMarkBitMap; // Under-construction mark bitmap
 409 
 410   BitMap                  _region_bm;
 411   BitMap                  _card_bm;
 412 
 413   // Heap bounds
 414   HeapWord*               _heap_start;
 415   HeapWord*               _heap_end;
 416 
 417   // Root region tracking and claiming
 418   CMRootRegions           _root_regions;
 419 
 420   // For gray objects
 421   CMMarkStack             _markStack; // Grey objects behind global finger
 422   HeapWord* volatile      _finger;  // The global finger, region aligned,
 423                                     // always points to the end of the
 424                                     // last claimed region
 425 
 426   // Marking tasks
 427   uint                    _max_worker_id;// Maximum worker id
 428   uint                    _active_tasks; // Task num currently active
 429   CMTask**                _tasks;        // Task queue array (max_worker_id len)
 430   CMTaskQueueSet*         _task_queues;  // Task queue set
 431   ParallelTaskTerminator  _terminator;   // For termination
 432 
 433   // Two sync barriers that are used to synchronize tasks when an
 434   // overflow occurs. The algorithm is the following. All tasks enter
 435   // the first one to ensure that they have all stopped manipulating
 436   // the global data structures. After they exit it, they re-initialize
 437   // their data structures and task 0 re-initializes the global data
 438   // structures. Then, they enter the second sync barrier. This
 439   // ensure, that no task starts doing work before all data
 440   // structures (local and global) have been re-initialized. When they
 441   // exit it, they are free to start working again.
 442   WorkGangBarrierSync     _first_overflow_barrier_sync;
 443   WorkGangBarrierSync     _second_overflow_barrier_sync;
 444 
 445   // This is set by any task, when an overflow on the global data
 446   // structures is detected
 447   volatile bool           _has_overflown;
 448   // True: marking is concurrent, false: we're in remark
 449   volatile bool           _concurrent;
 450   // Set at the end of a Full GC so that marking aborts
 451   volatile bool           _has_aborted;
 452   GCId                    _aborted_gc_id;
 453 
 454   // Used when remark aborts due to an overflow to indicate that
 455   // another concurrent marking phase should start
 456   volatile bool           _restart_for_overflow;
 457 
 458   // This is true from the very start of concurrent marking until the
 459   // point when all the tasks complete their work. It is really used
 460   // to determine the points between the end of concurrent marking and
 461   // time of remark.
 462   volatile bool           _concurrent_marking_in_progress;
 463 
 464   // Verbose level
 465   CMVerboseLevel          _verbose_level;
 466 
 467   // All of these times are in ms
 468   NumberSeq _init_times;
 469   NumberSeq _remark_times;
 470   NumberSeq   _remark_mark_times;
 471   NumberSeq   _remark_weak_ref_times;
 472   NumberSeq _cleanup_times;
 473   double    _total_counting_time;
 474   double    _total_rs_scrub_time;
 475 
 476   double*   _accum_task_vtime;   // Accumulated task vtime
 477 
 478   FlexibleWorkGang* _parallel_workers;
 479 
 480   ForceOverflowSettings _force_overflow_conc;
 481   ForceOverflowSettings _force_overflow_stw;
 482 
 483   void weakRefsWorkParallelPart(BoolObjectClosure* is_alive, bool purged_classes);
 484   void weakRefsWork(bool clear_all_soft_refs);
 485 
 486   void swapMarkBitMaps();
 487 
 488   // It resets the global marking data structures, as well as the
 489   // task local ones; should be called during initial mark.
 490   void reset();
 491 
 492   // Resets all the marking data structures. Called when we have to restart
 493   // marking or when marking completes (via set_non_marking_state below).
 494   void reset_marking_state(bool clear_overflow = true);
 495 
 496   // We do this after we're done with marking so that the marking data
 497   // structures are initialized to a sensible and predictable state.
 498   void set_non_marking_state();
 499 
 500   // Called to indicate how many threads are currently active.
 501   void set_concurrency(uint active_tasks);
 502 
 503   // It should be called to indicate which phase we're in (concurrent
 504   // mark or remark) and how many threads are currently active.
 505   void set_concurrency_and_phase(uint active_tasks, bool concurrent);
 506 
 507   // Prints all gathered CM-related statistics
 508   void print_stats();
 509 
 510   bool cleanup_list_is_empty() {
 511     return _cleanup_list.is_empty();
 512   }
 513 
 514   // Accessor methods
 515   uint parallel_marking_threads() const     { return _parallel_marking_threads; }
 516   uint max_parallel_marking_threads() const { return _max_parallel_marking_threads;}
 517   double sleep_factor()                     { return _sleep_factor; }
 518   double marking_task_overhead()            { return _marking_task_overhead;}
 519   double cleanup_sleep_factor()             { return _cleanup_sleep_factor; }
 520   double cleanup_task_overhead()            { return _cleanup_task_overhead;}
 521 
 522   HeapWord*               finger()          { return _finger;   }
 523   bool                    concurrent()      { return _concurrent; }
 524   uint                    active_tasks()    { return _active_tasks; }
 525   ParallelTaskTerminator* terminator()      { return &_terminator; }
 526 
 527   // It claims the next available region to be scanned by a marking
 528   // task/thread. It might return NULL if the next region is empty or
 529   // we have run out of regions. In the latter case, out_of_regions()
 530   // determines whether we've really run out of regions or the task
 531   // should call claim_region() again. This might seem a bit
 532   // awkward. Originally, the code was written so that claim_region()
 533   // either successfully returned with a non-empty region or there
 534   // were no more regions to be claimed. The problem with this was
 535   // that, in certain circumstances, it iterated over large chunks of
 536   // the heap finding only empty regions and, while it was working, it
 537   // was preventing the calling task to call its regular clock
 538   // method. So, this way, each task will spend very little time in
 539   // claim_region() and is allowed to call the regular clock method
 540   // frequently.
 541   HeapRegion* claim_region(uint worker_id);
 542 
 543   // It determines whether we've run out of regions to scan. Note that
 544   // the finger can point past the heap end in case the heap was expanded
 545   // to satisfy an allocation without doing a GC. This is fine, because all
 546   // objects in those regions will be considered live anyway because of
 547   // SATB guarantees (i.e. their TAMS will be equal to bottom).
 548   bool        out_of_regions() { return _finger >= _heap_end; }
 549 
 550   // Returns the task with the given id
 551   CMTask* task(int id) {
 552     assert(0 <= id && id < (int) _active_tasks,
 553            "task id not within active bounds");
 554     return _tasks[id];
 555   }
 556 
 557   // Returns the task queue with the given id
 558   CMTaskQueue* task_queue(int id) {
 559     assert(0 <= id && id < (int) _active_tasks,
 560            "task queue id not within active bounds");
 561     return (CMTaskQueue*) _task_queues->queue(id);
 562   }
 563 
 564   // Returns the task queue set
 565   CMTaskQueueSet* task_queues()  { return _task_queues; }
 566 
 567   // Access / manipulation of the overflow flag which is set to
 568   // indicate that the global stack has overflown
 569   bool has_overflown()           { return _has_overflown; }
 570   void set_has_overflown()       { _has_overflown = true; }
 571   void clear_has_overflown()     { _has_overflown = false; }
 572   bool restart_for_overflow()    { return _restart_for_overflow; }
 573 
 574   // Methods to enter the two overflow sync barriers
 575   void enter_first_sync_barrier(uint worker_id);
 576   void enter_second_sync_barrier(uint worker_id);
 577 
 578   ForceOverflowSettings* force_overflow_conc() {
 579     return &_force_overflow_conc;
 580   }
 581 
 582   ForceOverflowSettings* force_overflow_stw() {
 583     return &_force_overflow_stw;
 584   }
 585 
 586   ForceOverflowSettings* force_overflow() {
 587     if (concurrent()) {
 588       return force_overflow_conc();
 589     } else {
 590       return force_overflow_stw();
 591     }
 592   }
 593 
 594   // Live Data Counting data structures...
 595   // These data structures are initialized at the start of
 596   // marking. They are written to while marking is active.
 597   // They are aggregated during remark; the aggregated values
 598   // are then used to populate the _region_bm, _card_bm, and
 599   // the total live bytes, which are then subsequently updated
 600   // during cleanup.
 601 
 602   // An array of bitmaps (one bit map per task). Each bitmap
 603   // is used to record the cards spanned by the live objects
 604   // marked by that task/worker.
 605   BitMap*  _count_card_bitmaps;
 606 
 607   // Used to record the number of marked live bytes
 608   // (for each region, by worker thread).
 609   size_t** _count_marked_bytes;
 610 
 611   // Card index of the bottom of the G1 heap. Used for biasing indices into
 612   // the card bitmaps.
 613   intptr_t _heap_bottom_card_num;
 614 
 615   // Set to true when initialization is complete
 616   bool _completed_initialization;
 617 
 618 public:
 619   // Manipulation of the global mark stack.
 620   // Notice that the first mark_stack_push is CAS-based, whereas the
 621   // two below are Mutex-based. This is OK since the first one is only
 622   // called during evacuation pauses and doesn't compete with the
 623   // other two (which are called by the marking tasks during
 624   // concurrent marking or remark).
 625   bool mark_stack_push(oop p) {
 626     _markStack.par_push(p);
 627     if (_markStack.overflow()) {
 628       set_has_overflown();
 629       return false;
 630     }
 631     return true;
 632   }
 633   bool mark_stack_push(oop* arr, int n) {
 634     _markStack.par_push_arr(arr, n);
 635     if (_markStack.overflow()) {
 636       set_has_overflown();
 637       return false;
 638     }
 639     return true;
 640   }
 641   void mark_stack_pop(oop* arr, int max, int* n) {
 642     _markStack.par_pop_arr(arr, max, n);
 643   }
 644   size_t mark_stack_size()                { return _markStack.size(); }
 645   size_t partial_mark_stack_size_target() { return _markStack.maxElems()/3; }
 646   bool mark_stack_overflow()              { return _markStack.overflow(); }
 647   bool mark_stack_empty()                 { return _markStack.isEmpty(); }
 648 
 649   CMRootRegions* root_regions() { return &_root_regions; }
 650 
 651   bool concurrent_marking_in_progress() {
 652     return _concurrent_marking_in_progress;
 653   }
 654   void set_concurrent_marking_in_progress() {
 655     _concurrent_marking_in_progress = true;
 656   }
 657   void clear_concurrent_marking_in_progress() {
 658     _concurrent_marking_in_progress = false;
 659   }
 660 
 661   void update_accum_task_vtime(int i, double vtime) {
 662     _accum_task_vtime[i] += vtime;
 663   }
 664 
 665   double all_task_accum_vtime() {
 666     double ret = 0.0;
 667     for (uint i = 0; i < _max_worker_id; ++i)
 668       ret += _accum_task_vtime[i];
 669     return ret;
 670   }
 671 
 672   // Attempts to steal an object from the task queues of other tasks
 673   bool try_stealing(uint worker_id, int* hash_seed, oop& obj) {
 674     return _task_queues->steal(worker_id, hash_seed, obj);
 675   }
 676 
 677   ConcurrentMark(G1CollectedHeap* g1h,
 678                  G1RegionToSpaceMapper* prev_bitmap_storage,
 679                  G1RegionToSpaceMapper* next_bitmap_storage);
 680   ~ConcurrentMark();
 681 
 682   ConcurrentMarkThread* cmThread() { return _cmThread; }
 683 
 684   CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; }
 685   CMBitMap*   nextMarkBitMap() const { return _nextMarkBitMap; }
 686 
 687   // Returns the number of GC threads to be used in a concurrent
 688   // phase based on the number of GC threads being used in a STW
 689   // phase.
 690   uint scale_parallel_threads(uint n_par_threads);
 691 
 692   // Calculates the number of GC threads to be used in a concurrent phase.
 693   uint calc_parallel_marking_threads();
 694 
 695   // The following three are interaction between CM and
 696   // G1CollectedHeap
 697 
 698   // This notifies CM that a root during initial-mark needs to be
 699   // grayed. It is MT-safe. word_size is the size of the object in
 700   // words. It is passed explicitly as sometimes we cannot calculate
 701   // it from the given object because it might be in an inconsistent
 702   // state (e.g., in to-space and being copied). So the caller is
 703   // responsible for dealing with this issue (e.g., get the size from
 704   // the from-space image when the to-space image might be
 705   // inconsistent) and always passing the size. hr is the region that
 706   // contains the object and it's passed optionally from callers who
 707   // might already have it (no point in recalculating it).
 708   inline void grayRoot(oop obj,
 709                        size_t word_size,
 710                        uint worker_id,
 711                        HeapRegion* hr = NULL);
 712 
 713   // It iterates over the heap and for each object it comes across it
 714   // will dump the contents of its reference fields, as well as
 715   // liveness information for the object and its referents. The dump
 716   // will be written to a file with the following name:
 717   // G1PrintReachableBaseFile + "." + str.
 718   // vo decides whether the prev (vo == UsePrevMarking), the next
 719   // (vo == UseNextMarking) marking information, or the mark word
 720   // (vo == UseMarkWord) will be used to determine the liveness of
 721   // each object / referent.
 722   // If all is true, all objects in the heap will be dumped, otherwise
 723   // only the live ones. In the dump the following symbols / breviations
 724   // are used:
 725   //   M : an explicitly live object (its bitmap bit is set)
 726   //   > : an implicitly live object (over tams)
 727   //   O : an object outside the G1 heap (typically: in the perm gen)
 728   //   NOT : a reference field whose referent is not live
 729   //   AND MARKED : indicates that an object is both explicitly and
 730   //   implicitly live (it should be one or the other, not both)
 731   void print_reachable(const char* str,
 732                        VerifyOption vo,
 733                        bool all) PRODUCT_RETURN;
 734 
 735   // Clear the next marking bitmap (will be called concurrently).
 736   void clearNextBitmap();
 737 
 738   // Return whether the next mark bitmap has no marks set. To be used for assertions
 739   // only. Will not yield to pause requests.
 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 or
 771   // next 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 
 776   // Notify data structures that a GC has started.
 777   void note_start_of_gc() {
 778     _markStack.note_start_of_gc();
 779   }
 780 
 781   // Notify data structures that a GC is finished.
 782   void note_end_of_gc() {
 783     _markStack.note_end_of_gc();
 784   }
 785 
 786   // Verify that there are no CSet oops on the stacks (taskqueues /
 787   // global mark stack), enqueued SATB buffers, per-thread SATB
 788   // buffers, and fingers (global / per-task). The boolean parameters
 789   // decide which of the above data structures to verify. If marking
 790   // is not in progress, it's a no-op.
 791   void verify_no_cset_oops(bool verify_stacks,
 792                            bool verify_enqueued_buffers,
 793                            bool verify_thread_buffers,
 794                            bool verify_fingers) PRODUCT_RETURN;
 795 
 796   bool isPrevMarked(oop p) const {
 797     assert(p != NULL && p->is_oop(), "expected an oop");
 798     HeapWord* addr = (HeapWord*)p;
 799     assert(addr >= _prevMarkBitMap->startWord() ||
 800            addr < _prevMarkBitMap->endWord(), "in a region");
 801 
 802     return _prevMarkBitMap->isMarked(addr);
 803   }
 804 
 805   inline bool do_yield_check(uint worker_i = 0);
 806 
 807   // Called to abort the marking cycle after a Full GC takes place.
 808   void abort();
 809 
 810   bool has_aborted()      { return _has_aborted; }
 811 
 812   const GCId& concurrent_gc_id();
 813 
 814   // This prints the global/local fingers. It is used for debugging.
 815   NOT_PRODUCT(void print_finger();)
 816 
 817   void print_summary_info();
 818 
 819   void print_worker_threads_on(outputStream* st) const;
 820 
 821   void print_on_error(outputStream* st) const;
 822 
 823   // The following indicate whether a given verbose level has been
 824   // set. Notice that anything above stats is conditional to
 825   // _MARKING_VERBOSE_ having been set to 1
 826   bool verbose_stats() {
 827     return _verbose_level >= stats_verbose;
 828   }
 829   bool verbose_low() {
 830     return _MARKING_VERBOSE_ && _verbose_level >= low_verbose;
 831   }
 832   bool verbose_medium() {
 833     return _MARKING_VERBOSE_ && _verbose_level >= medium_verbose;
 834   }
 835   bool verbose_high() {
 836     return _MARKING_VERBOSE_ && _verbose_level >= high_verbose;
 837   }
 838 
 839   // Liveness counting
 840 
 841   // Utility routine to set an exclusive range of cards on the given
 842   // card liveness bitmap
 843   inline void set_card_bitmap_range(BitMap* card_bm,
 844                                     BitMap::idx_t start_idx,
 845                                     BitMap::idx_t end_idx,
 846                                     bool is_par);
 847 
 848   // Returns the card number of the bottom of the G1 heap.
 849   // Used in biasing indices into accounting card bitmaps.
 850   intptr_t heap_bottom_card_num() const {
 851     return _heap_bottom_card_num;
 852   }
 853 
 854   // Returns the card bitmap for a given task or worker id.
 855   BitMap* count_card_bitmap_for(uint worker_id) {
 856     assert(worker_id < _max_worker_id, "oob");
 857     assert(_count_card_bitmaps != NULL, "uninitialized");
 858     BitMap* task_card_bm = &_count_card_bitmaps[worker_id];
 859     assert(task_card_bm->size() == _card_bm.size(), "size mismatch");
 860     return task_card_bm;
 861   }
 862 
 863   // Returns the array containing the marked bytes for each region,
 864   // for the given worker or task id.
 865   size_t* count_marked_bytes_array_for(uint worker_id) {
 866     assert(worker_id < _max_worker_id, "oob");
 867     assert(_count_marked_bytes != NULL, "uninitialized");
 868     size_t* marked_bytes_array = _count_marked_bytes[worker_id];
 869     assert(marked_bytes_array != NULL, "uninitialized");
 870     return marked_bytes_array;
 871   }
 872 
 873   // Returns the index in the liveness accounting card table bitmap
 874   // for the given address
 875   inline BitMap::idx_t card_bitmap_index_for(HeapWord* addr);
 876 
 877   // Counts the size of the given memory region in the the given
 878   // marked_bytes array slot for the given HeapRegion.
 879   // Sets the bits in the given card bitmap that are associated with the
 880   // cards that are spanned by the memory region.
 881   inline void count_region(MemRegion mr,
 882                            HeapRegion* hr,
 883                            size_t* marked_bytes_array,
 884                            BitMap* task_card_bm);
 885 
 886   // Counts the given memory region in the task/worker counting
 887   // data structures for the given worker id.
 888   inline void count_region(MemRegion mr, HeapRegion* hr, uint worker_id);
 889 
 890   // Counts the given object in the given task/worker counting
 891   // data structures.
 892   inline void count_object(oop obj,
 893                            HeapRegion* hr,
 894                            size_t* marked_bytes_array,
 895                            BitMap* task_card_bm);
 896 
 897   // Attempts to mark the given object and, if successful, counts
 898   // the object in the given task/worker counting structures.
 899   inline bool par_mark_and_count(oop obj,
 900                                  HeapRegion* hr,
 901                                  size_t* marked_bytes_array,
 902                                  BitMap* task_card_bm);
 903 
 904   // Attempts to mark the given object and, if successful, counts
 905   // the object in the task/worker counting structures for the
 906   // given worker id.
 907   inline bool par_mark_and_count(oop obj,
 908                                  size_t word_size,
 909                                  HeapRegion* hr,
 910                                  uint worker_id);
 911 
 912   // Returns true if initialization was successfully completed.
 913   bool completed_initialization() const {
 914     return _completed_initialization;
 915   }
 916 
 917 protected:
 918   // Clear all the per-task bitmaps and arrays used to store the
 919   // counting data.
 920   void clear_all_count_data();
 921 
 922   // Aggregates the counting data for each worker/task
 923   // that was constructed while marking. Also sets
 924   // the amount of marked bytes for each region and
 925   // the top at concurrent mark count.
 926   void aggregate_count_data();
 927 
 928   // Verification routine
 929   void verify_count_data();
 930 };
 931 
 932 // A class representing a marking task.
 933 class CMTask : public TerminatorTerminator {
 934 private:
 935   enum PrivateConstants {
 936     // the regular clock call is called once the scanned words reaches
 937     // this limit
 938     words_scanned_period          = 12*1024,
 939     // the regular clock call is called once the number of visited
 940     // references reaches this limit
 941     refs_reached_period           = 384,
 942     // initial value for the hash seed, used in the work stealing code
 943     init_hash_seed                = 17,
 944     // how many entries will be transferred between global stack and
 945     // local queues
 946     global_stack_transfer_size    = 16
 947   };
 948 
 949   uint                        _worker_id;
 950   G1CollectedHeap*            _g1h;
 951   ConcurrentMark*             _cm;
 952   CMBitMap*                   _nextMarkBitMap;
 953   // the task queue of this task
 954   CMTaskQueue*                _task_queue;
 955 private:
 956   // the task queue set---needed for stealing
 957   CMTaskQueueSet*             _task_queues;
 958   // indicates whether the task has been claimed---this is only  for
 959   // debugging purposes
 960   bool                        _claimed;
 961 
 962   // number of calls to this task
 963   int                         _calls;
 964 
 965   // when the virtual timer reaches this time, the marking step should
 966   // exit
 967   double                      _time_target_ms;
 968   // the start time of the current marking step
 969   double                      _start_time_ms;
 970 
 971   // the oop closure used for iterations over oops
 972   G1CMOopClosure*             _cm_oop_closure;
 973 
 974   // the region this task is scanning, NULL if we're not scanning any
 975   HeapRegion*                 _curr_region;
 976   // the local finger of this task, NULL if we're not scanning a region
 977   HeapWord*                   _finger;
 978   // limit of the region this task is scanning, NULL if we're not scanning one
 979   HeapWord*                   _region_limit;
 980 
 981   // the number of words this task has scanned
 982   size_t                      _words_scanned;
 983   // When _words_scanned reaches this limit, the regular clock is
 984   // called. Notice that this might be decreased under certain
 985   // circumstances (i.e. when we believe that we did an expensive
 986   // operation).
 987   size_t                      _words_scanned_limit;
 988   // the initial value of _words_scanned_limit (i.e. what it was
 989   // before it was decreased).
 990   size_t                      _real_words_scanned_limit;
 991 
 992   // the number of references this task has visited
 993   size_t                      _refs_reached;
 994   // When _refs_reached reaches this limit, the regular clock is
 995   // called. Notice this this might be decreased under certain
 996   // circumstances (i.e. when we believe that we did an expensive
 997   // operation).
 998   size_t                      _refs_reached_limit;
 999   // the initial value of _refs_reached_limit (i.e. what it was before
1000   // it was decreased).
1001   size_t                      _real_refs_reached_limit;
1002 
1003   // used by the work stealing stuff
1004   int                         _hash_seed;
1005   // if this is true, then the task has aborted for some reason
1006   bool                        _has_aborted;
1007   // set when the task aborts because it has met its time quota
1008   bool                        _has_timed_out;
1009   // true when we're draining SATB buffers; this avoids the task
1010   // aborting due to SATB buffers being available (as we're already
1011   // dealing with them)
1012   bool                        _draining_satb_buffers;
1013 
1014   // number sequence of past step times
1015   NumberSeq                   _step_times_ms;
1016   // elapsed time of this task
1017   double                      _elapsed_time_ms;
1018   // termination time of this task
1019   double                      _termination_time_ms;
1020   // when this task got into the termination protocol
1021   double                      _termination_start_time_ms;
1022 
1023   // true when the task is during a concurrent phase, false when it is
1024   // in the remark phase (so, in the latter case, we do not have to
1025   // check all the things that we have to check during the concurrent
1026   // phase, i.e. SATB buffer availability...)
1027   bool                        _concurrent;
1028 
1029   TruncatedSeq                _marking_step_diffs_ms;
1030 
1031   // Counting data structures. Embedding the task's marked_bytes_array
1032   // and card bitmap into the actual task saves having to go through
1033   // the ConcurrentMark object.
1034   size_t*                     _marked_bytes_array;
1035   BitMap*                     _card_bm;
1036 
1037   // LOTS of statistics related with this task
1038 #if _MARKING_STATS_
1039   NumberSeq                   _all_clock_intervals_ms;
1040   double                      _interval_start_time_ms;
1041 
1042   int                         _aborted;
1043   int                         _aborted_overflow;
1044   int                         _aborted_cm_aborted;
1045   int                         _aborted_yield;
1046   int                         _aborted_timed_out;
1047   int                         _aborted_satb;
1048   int                         _aborted_termination;
1049 
1050   int                         _steal_attempts;
1051   int                         _steals;
1052 
1053   int                         _clock_due_to_marking;
1054   int                         _clock_due_to_scanning;
1055 
1056   int                         _local_pushes;
1057   int                         _local_pops;
1058   int                         _local_max_size;
1059   int                         _objs_scanned;
1060 
1061   int                         _global_pushes;
1062   int                         _global_pops;
1063   int                         _global_max_size;
1064 
1065   int                         _global_transfers_to;
1066   int                         _global_transfers_from;
1067 
1068   int                         _regions_claimed;
1069   int                         _objs_found_on_bitmap;
1070 
1071   int                         _satb_buffers_processed;
1072 #endif // _MARKING_STATS_
1073 
1074   // it updates the local fields after this task has claimed
1075   // a new region to scan
1076   void setup_for_region(HeapRegion* hr);
1077   // it brings up-to-date the limit of the region
1078   void update_region_limit();
1079 
1080   // called when either the words scanned or the refs visited limit
1081   // has been reached
1082   void reached_limit();
1083   // recalculates the words scanned and refs visited limits
1084   void recalculate_limits();
1085   // decreases the words scanned and refs visited limits when we reach
1086   // an expensive operation
1087   void decrease_limits();
1088   // it checks whether the words scanned or refs visited reached their
1089   // respective limit and calls reached_limit() if they have
1090   void check_limits() {
1091     if (_words_scanned >= _words_scanned_limit ||
1092         _refs_reached >= _refs_reached_limit) {
1093       reached_limit();
1094     }
1095   }
1096   // this is supposed to be called regularly during a marking step as
1097   // it checks a bunch of conditions that might cause the marking step
1098   // to abort
1099   void regular_clock_call();
1100   bool concurrent() { return _concurrent; }
1101 
1102 public:
1103   // It resets the task; it should be called right at the beginning of
1104   // a marking phase.
1105   void reset(CMBitMap* _nextMarkBitMap);
1106   // it clears all the fields that correspond to a claimed region.
1107   void clear_region_fields();
1108 
1109   void set_concurrent(bool concurrent) { _concurrent = concurrent; }
1110 
1111   // The main method of this class which performs a marking step
1112   // trying not to exceed the given duration. However, it might exit
1113   // prematurely, according to some conditions (i.e. SATB buffers are
1114   // available for processing).
1115   void do_marking_step(double target_ms,
1116                        bool do_termination,
1117                        bool is_serial);
1118 
1119   // These two calls start and stop the timer
1120   void record_start_time() {
1121     _elapsed_time_ms = os::elapsedTime() * 1000.0;
1122   }
1123   void record_end_time() {
1124     _elapsed_time_ms = os::elapsedTime() * 1000.0 - _elapsed_time_ms;
1125   }
1126 
1127   // returns the worker ID associated with this task.
1128   uint worker_id() { return _worker_id; }
1129 
1130   // From TerminatorTerminator. It determines whether this task should
1131   // exit the termination protocol after it's entered it.
1132   virtual bool should_exit_termination();
1133 
1134   // Resets the local region fields after a task has finished scanning a
1135   // region; or when they have become stale as a result of the region
1136   // being evacuated.
1137   void giveup_current_region();
1138 
1139   HeapWord* finger()            { return _finger; }
1140 
1141   bool has_aborted()            { return _has_aborted; }
1142   void set_has_aborted()        { _has_aborted = true; }
1143   void clear_has_aborted()      { _has_aborted = false; }
1144   bool has_timed_out()          { return _has_timed_out; }
1145   bool claimed()                { return _claimed; }
1146 
1147   void set_cm_oop_closure(G1CMOopClosure* cm_oop_closure);
1148 
1149   // It grays the object by marking it and, if necessary, pushing it
1150   // on the local queue
1151   inline void deal_with_reference(oop obj);
1152 
1153   // It scans an object and visits its children.
1154   void scan_object(oop obj);
1155 
1156   // It pushes an object on the local queue.
1157   inline void push(oop obj);
1158 
1159   // These two move entries to/from the global stack.
1160   void move_entries_to_global_stack();
1161   void get_entries_from_global_stack();
1162 
1163   // It pops and scans objects from the local queue. If partially is
1164   // true, then it stops when the queue size is of a given limit. If
1165   // partially is false, then it stops when the queue is empty.
1166   void drain_local_queue(bool partially);
1167   // It moves entries from the global stack to the local queue and
1168   // drains the local queue. If partially is true, then it stops when
1169   // both the global stack and the local queue reach a given size. If
1170   // partially if false, it tries to empty them totally.
1171   void drain_global_stack(bool partially);
1172   // It keeps picking SATB buffers and processing them until no SATB
1173   // buffers are available.
1174   void drain_satb_buffers();
1175 
1176   // moves the local finger to a new location
1177   inline void move_finger_to(HeapWord* new_finger) {
1178     assert(new_finger >= _finger && new_finger < _region_limit, "invariant");
1179     _finger = new_finger;
1180   }
1181 
1182   CMTask(uint worker_id,
1183          ConcurrentMark *cm,
1184          size_t* marked_bytes,
1185          BitMap* card_bm,
1186          CMTaskQueue* task_queue,
1187          CMTaskQueueSet* task_queues);
1188 
1189   // it prints statistics associated with this task
1190   void print_stats();
1191 
1192 #if _MARKING_STATS_
1193   void increase_objs_found_on_bitmap() { ++_objs_found_on_bitmap; }
1194 #endif // _MARKING_STATS_
1195 };
1196 
1197 // Class that's used to to print out per-region liveness
1198 // information. It's currently used at the end of marking and also
1199 // after we sort the old regions at the end of the cleanup operation.
1200 class G1PrintRegionLivenessInfoClosure: public HeapRegionClosure {
1201 private:
1202   outputStream* _out;
1203 
1204   // Accumulators for these values.
1205   size_t _total_used_bytes;
1206   size_t _total_capacity_bytes;
1207   size_t _total_prev_live_bytes;
1208   size_t _total_next_live_bytes;
1209 
1210   // These are set up when we come across a "stars humongous" region
1211   // (as this is where most of this information is stored, not in the
1212   // subsequent "continues humongous" regions). After that, for every
1213   // region in a given humongous region series we deduce the right
1214   // values for it by simply subtracting the appropriate amount from
1215   // these fields. All these values should reach 0 after we've visited
1216   // the last region in the series.
1217   size_t _hum_used_bytes;
1218   size_t _hum_capacity_bytes;
1219   size_t _hum_prev_live_bytes;
1220   size_t _hum_next_live_bytes;
1221 
1222   // Accumulator for the remembered set size
1223   size_t _total_remset_bytes;
1224 
1225   // Accumulator for strong code roots memory size
1226   size_t _total_strong_code_roots_bytes;
1227 
1228   static double perc(size_t val, size_t total) {
1229     if (total == 0) {
1230       return 0.0;
1231     } else {
1232       return 100.0 * ((double) val / (double) total);
1233     }
1234   }
1235 
1236   static double bytes_to_mb(size_t val) {
1237     return (double) val / (double) M;
1238   }
1239 
1240   // See the .cpp file.
1241   size_t get_hum_bytes(size_t* hum_bytes);
1242   void get_hum_bytes(size_t* used_bytes, size_t* capacity_bytes,
1243                      size_t* prev_live_bytes, size_t* next_live_bytes);
1244 
1245 public:
1246   // The header and footer are printed in the constructor and
1247   // destructor respectively.
1248   G1PrintRegionLivenessInfoClosure(outputStream* out, const char* phase_name);
1249   virtual bool doHeapRegion(HeapRegion* r);
1250   ~G1PrintRegionLivenessInfoClosure();
1251 };
1252 
1253 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_HPP
--- EOF ---