ysr@777: /*
xdono@1014:  * Copyright 2001-2009 Sun Microsystems, Inc.  All Rights Reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
ysr@777:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
ysr@777:  * CA 95054 USA or visit www.sun.com if you need additional information or
ysr@777:  * have any questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
ysr@777: class G1CollectedHeap;
ysr@777: class CMTask;
ysr@777: typedef GenericTaskQueue<oop> CMTaskQueue;
ysr@777: typedef GenericTaskQueueSet<oop> CMTaskQueueSet;
ysr@777: 
ysr@777: // A generic CM bit map.  This is essentially a wrapper around the BitMap
ysr@777: // class, with one bit per (1<<_shifter) HeapWords.
ysr@777: 
apetrusenko@984: class CMBitMapRO VALUE_OBJ_CLASS_SPEC {
ysr@777:  protected:
ysr@777:   HeapWord* _bmStartWord;      // base address of range covered by map
ysr@777:   size_t    _bmWordSize;       // map size (in #HeapWords covered)
ysr@777:   const int _shifter;          // map to char or bit
ysr@777:   VirtualSpace _virtual_space; // underlying the bit map
ysr@777:   BitMap    _bm;               // the bit map itself
ysr@777: 
ysr@777:  public:
ysr@777:   // constructor
ysr@777:   CMBitMapRO(ReservedSpace rs, int shifter);
ysr@777: 
ysr@777:   enum { do_yield = true };
ysr@777: 
ysr@777:   // inquiries
ysr@777:   HeapWord* startWord()   const { return _bmStartWord; }
ysr@777:   size_t    sizeInWords() const { return _bmWordSize;  }
ysr@777:   // the following is one past the last word in space
ysr@777:   HeapWord* endWord()     const { return _bmStartWord + _bmWordSize; }
ysr@777: 
ysr@777:   // read marks
ysr@777: 
ysr@777:   bool isMarked(HeapWord* addr) const {
ysr@777:     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
ysr@777:            "outside underlying space?");
ysr@777:     return _bm.at(heapWordToOffset(addr));
ysr@777:   }
ysr@777: 
ysr@777:   // iteration
ysr@777:   bool iterate(BitMapClosure* cl) { return _bm.iterate(cl); }
ysr@777:   bool iterate(BitMapClosure* cl, MemRegion mr);
ysr@777: 
ysr@777:   // Return the address corresponding to the next marked bit at or after
ysr@777:   // "addr", and before "limit", if "limit" is non-NULL.  If there is no
ysr@777:   // such bit, returns "limit" if that is non-NULL, or else "endWord()".
ysr@777:   HeapWord* getNextMarkedWordAddress(HeapWord* addr,
ysr@777:                                      HeapWord* limit = NULL) const;
ysr@777:   // Return the address corresponding to the next unmarked bit at or after
ysr@777:   // "addr", and before "limit", if "limit" is non-NULL.  If there is no
ysr@777:   // such bit, returns "limit" if that is non-NULL, or else "endWord()".
ysr@777:   HeapWord* getNextUnmarkedWordAddress(HeapWord* addr,
ysr@777:                                        HeapWord* limit = NULL) const;
ysr@777: 
ysr@777:   // conversion utilities
ysr@777:   // XXX Fix these so that offsets are size_t's...
ysr@777:   HeapWord* offsetToHeapWord(size_t offset) const {
ysr@777:     return _bmStartWord + (offset << _shifter);
ysr@777:   }
ysr@777:   size_t heapWordToOffset(HeapWord* addr) const {
ysr@777:     return pointer_delta(addr, _bmStartWord) >> _shifter;
ysr@777:   }
ysr@777:   int heapWordDiffToOffsetDiff(size_t diff) const;
ysr@777:   HeapWord* nextWord(HeapWord* addr) {
ysr@777:     return offsetToHeapWord(heapWordToOffset(addr) + 1);
ysr@777:   }
ysr@777: 
ysr@777:   void mostly_disjoint_range_union(BitMap*   from_bitmap,
ysr@777:                                    size_t    from_start_index,
ysr@777:                                    HeapWord* to_start_word,
ysr@777:                                    size_t    word_num);
ysr@777: 
ysr@777:   // debugging
ysr@777:   NOT_PRODUCT(bool covers(ReservedSpace rs) const;)
ysr@777: };
ysr@777: 
ysr@777: class CMBitMap : public CMBitMapRO {
ysr@777: 
ysr@777:  public:
ysr@777:   // constructor
ysr@777:   CMBitMap(ReservedSpace rs, int shifter) :
ysr@777:     CMBitMapRO(rs, shifter) {}
ysr@777: 
ysr@777:   // write marks
ysr@777:   void mark(HeapWord* addr) {
ysr@777:     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
ysr@777:            "outside underlying space?");
ysr@777:     _bm.at_put(heapWordToOffset(addr), true);
ysr@777:   }
ysr@777:   void clear(HeapWord* addr) {
ysr@777:     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
ysr@777:            "outside underlying space?");
ysr@777:     _bm.at_put(heapWordToOffset(addr), false);
ysr@777:   }
ysr@777:   bool parMark(HeapWord* addr) {
ysr@777:     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
ysr@777:            "outside underlying space?");
ysr@777:     return _bm.par_at_put(heapWordToOffset(addr), true);
ysr@777:   }
ysr@777:   bool parClear(HeapWord* addr) {
ysr@777:     assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
ysr@777:            "outside underlying space?");
ysr@777:     return _bm.par_at_put(heapWordToOffset(addr), false);
ysr@777:   }
ysr@777:   void markRange(MemRegion mr);
ysr@777:   void clearAll();
ysr@777:   void clearRange(MemRegion mr);
ysr@777: 
ysr@777:   // Starting at the bit corresponding to "addr" (inclusive), find the next
ysr@777:   // "1" bit, if any.  This bit starts some run of consecutive "1"'s; find
ysr@777:   // the end of this run (stopping at "end_addr").  Return the MemRegion
ysr@777:   // covering from the start of the region corresponding to the first bit
ysr@777:   // of the run to the end of the region corresponding to the last bit of
ysr@777:   // the run.  If there is no "1" bit at or after "addr", return an empty
ysr@777:   // MemRegion.
ysr@777:   MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr);
ysr@777: };
ysr@777: 
ysr@777: // Represents a marking stack used by the CM collector.
ysr@777: // Ideally this should be GrowableArray<> just like MSC's marking stack(s).
apetrusenko@984: class CMMarkStack VALUE_OBJ_CLASS_SPEC {
ysr@777:   ConcurrentMark* _cm;
ysr@777:   oop*   _base;      // bottom of stack
ysr@777:   jint   _index;     // one more than last occupied index
ysr@777:   jint   _capacity;  // max #elements
ysr@777:   jint   _oops_do_bound;  // Number of elements to include in next iteration.
ysr@777:   NOT_PRODUCT(jint _max_depth;)  // max depth plumbed during run
ysr@777: 
ysr@777:   bool   _overflow;
ysr@777:   DEBUG_ONLY(bool _drain_in_progress;)
ysr@777:   DEBUG_ONLY(bool _drain_in_progress_yields;)
ysr@777: 
ysr@777:  public:
ysr@777:   CMMarkStack(ConcurrentMark* cm);
ysr@777:   ~CMMarkStack();
ysr@777: 
ysr@777:   void allocate(size_t size);
ysr@777: 
ysr@777:   oop pop() {
ysr@777:     if (!isEmpty()) {
ysr@777:       return _base[--_index] ;
ysr@777:     }
ysr@777:     return NULL;
ysr@777:   }
ysr@777: 
ysr@777:   // If overflow happens, don't do the push, and record the overflow.
ysr@777:   // *Requires* that "ptr" is already marked.
ysr@777:   void push(oop ptr) {
ysr@777:     if (isFull()) {
ysr@777:       // Record overflow.
ysr@777:       _overflow = true;
ysr@777:       return;
ysr@777:     } else {
ysr@777:       _base[_index++] = ptr;
ysr@777:       NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index));
ysr@777:     }
ysr@777:   }
ysr@777:   // Non-block impl.  Note: concurrency is allowed only with other
ysr@777:   // "par_push" operations, not with "pop" or "drain".  We would need
ysr@777:   // parallel versions of them if such concurrency was desired.
ysr@777:   void par_push(oop ptr);
ysr@777: 
ysr@777:   // Pushes the first "n" elements of "ptr_arr" on the stack.
ysr@777:   // Non-block impl.  Note: concurrency is allowed only with other
ysr@777:   // "par_adjoin_arr" or "push" operations, not with "pop" or "drain".
ysr@777:   void par_adjoin_arr(oop* ptr_arr, int n);
ysr@777: 
ysr@777:   // Pushes the first "n" elements of "ptr_arr" on the stack.
ysr@777:   // Locking impl: concurrency is allowed only with
ysr@777:   // "par_push_arr" and/or "par_pop_arr" operations, which use the same
ysr@777:   // locking strategy.
ysr@777:   void par_push_arr(oop* ptr_arr, int n);
ysr@777: 
ysr@777:   // If returns false, the array was empty.  Otherwise, removes up to "max"
ysr@777:   // elements from the stack, and transfers them to "ptr_arr" in an
ysr@777:   // unspecified order.  The actual number transferred is given in "n" ("n
ysr@777:   // == 0" is deliberately redundant with the return value.)  Locking impl:
ysr@777:   // concurrency is allowed only with "par_push_arr" and/or "par_pop_arr"
ysr@777:   // operations, which use the same locking strategy.
ysr@777:   bool par_pop_arr(oop* ptr_arr, int max, int* n);
ysr@777: 
ysr@777:   // Drain the mark stack, applying the given closure to all fields of
ysr@777:   // objects on the stack.  (That is, continue until the stack is empty,
ysr@777:   // even if closure applications add entries to the stack.)  The "bm"
ysr@777:   // argument, if non-null, may be used to verify that only marked objects
ysr@777:   // are on the mark stack.  If "yield_after" is "true", then the
ysr@777:   // concurrent marker performing the drain offers to yield after
ysr@777:   // processing each object.  If a yield occurs, stops the drain operation
ysr@777:   // and returns false.  Otherwise, returns true.
ysr@777:   template<class OopClosureClass>
ysr@777:   bool drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after = false);
ysr@777: 
ysr@777:   bool isEmpty()    { return _index == 0; }
ysr@777:   bool isFull()     { return _index == _capacity; }
ysr@777:   int maxElems()    { return _capacity; }
ysr@777: 
ysr@777:   bool overflow() { return _overflow; }
ysr@777:   void clear_overflow() { _overflow = false; }
ysr@777: 
ysr@777:   int  size() { return _index; }
ysr@777: 
ysr@777:   void setEmpty()   { _index = 0; clear_overflow(); }
ysr@777: 
ysr@777:   // Record the current size; a subsequent "oops_do" will iterate only over
ysr@777:   // indices valid at the time of this call.
ysr@777:   void set_oops_do_bound(jint bound = -1) {
ysr@777:     if (bound == -1) {
ysr@777:       _oops_do_bound = _index;
ysr@777:     } else {
ysr@777:       _oops_do_bound = bound;
ysr@777:     }
ysr@777:   }
ysr@777:   jint oops_do_bound() { return _oops_do_bound; }
ysr@777:   // iterate over the oops in the mark stack, up to the bound recorded via
ysr@777:   // the call above.
ysr@777:   void oops_do(OopClosure* f);
ysr@777: };
ysr@777: 
apetrusenko@984: class CMRegionStack VALUE_OBJ_CLASS_SPEC {
ysr@777:   MemRegion* _base;
ysr@777:   jint _capacity;
ysr@777:   jint _index;
ysr@777:   jint _oops_do_bound;
ysr@777:   bool _overflow;
ysr@777: public:
ysr@777:   CMRegionStack();
ysr@777:   ~CMRegionStack();
ysr@777:   void allocate(size_t size);
ysr@777: 
ysr@777:   // This is lock-free; assumes that it will only be called in parallel
ysr@777:   // with other "push" operations (no pops).
ysr@777:   void push(MemRegion mr);
ysr@777: 
ysr@777:   // Lock-free; assumes that it will only be called in parallel
ysr@777:   // with other "pop" operations (no pushes).
ysr@777:   MemRegion pop();
ysr@777: 
ysr@777:   bool isEmpty()    { return _index == 0; }
ysr@777:   bool isFull()     { return _index == _capacity; }
ysr@777: 
ysr@777:   bool overflow() { return _overflow; }
ysr@777:   void clear_overflow() { _overflow = false; }
ysr@777: 
ysr@777:   int  size() { return _index; }
ysr@777: 
ysr@777:   // It iterates over the entries in the region stack and it
ysr@777:   // invalidates (i.e. assigns MemRegion()) the ones that point to
ysr@777:   // regions in the collection set.
ysr@777:   bool invalidate_entries_into_cset();
ysr@777: 
ysr@777:   // This gives an upper bound up to which the iteration in
ysr@777:   // invalidate_entries_into_cset() will reach. This prevents
ysr@777:   // newly-added entries to be unnecessarily scanned.
ysr@777:   void set_oops_do_bound() {
ysr@777:     _oops_do_bound = _index;
ysr@777:   }
ysr@777: 
ysr@777:   void setEmpty()   { _index = 0; clear_overflow(); }
ysr@777: };
ysr@777: 
ysr@777: // this will enable a variety of different statistics per GC task
ysr@777: #define _MARKING_STATS_       0
ysr@777: // this will enable the higher verbose levels
ysr@777: #define _MARKING_VERBOSE_     0
ysr@777: 
ysr@777: #if _MARKING_STATS_
ysr@777: #define statsOnly(statement)  \
ysr@777: do {                          \
ysr@777:   statement ;                 \
ysr@777: } while (0)
ysr@777: #else // _MARKING_STATS_
ysr@777: #define statsOnly(statement)  \
ysr@777: do {                          \
ysr@777: } while (0)
ysr@777: #endif // _MARKING_STATS_
ysr@777: 
ysr@777: // Some extra guarantees that I like to also enable in optimised mode
ysr@777: // when debugging. If you want to enable them, comment out the assert
ysr@777: // macro and uncomment out the guaratee macro
ysr@777: // #define tmp_guarantee_CM(expr, str) guarantee(expr, str)
ysr@777: #define tmp_guarantee_CM(expr, str) assert(expr, str)
ysr@777: 
ysr@777: typedef enum {
ysr@777:   no_verbose  = 0,   // verbose turned off
ysr@777:   stats_verbose,     // only prints stats at the end of marking
ysr@777:   low_verbose,       // low verbose, mostly per region and per major event
ysr@777:   medium_verbose,    // a bit more detailed than low
ysr@777:   high_verbose       // per object verbose
ysr@777: } CMVerboseLevel;
ysr@777: 
ysr@777: 
ysr@777: class ConcurrentMarkThread;
ysr@777: 
apetrusenko@984: class ConcurrentMark: public CHeapObj {
ysr@777:   friend class ConcurrentMarkThread;
ysr@777:   friend class CMTask;
ysr@777:   friend class CMBitMapClosure;
ysr@777:   friend class CSMarkOopClosure;
ysr@777:   friend class CMGlobalObjectClosure;
ysr@777:   friend class CMRemarkTask;
ysr@777:   friend class CMConcurrentMarkingTask;
ysr@777:   friend class G1ParNoteEndTask;
ysr@777:   friend class CalcLiveObjectsClosure;
ysr@777: 
ysr@777: protected:
ysr@777:   ConcurrentMarkThread* _cmThread;   // the thread doing the work
ysr@777:   G1CollectedHeap*      _g1h;        // the heap.
ysr@777:   size_t                _parallel_marking_threads; // the number of marking
ysr@777:                                                    // threads we'll use
ysr@777:   double                _sleep_factor; // how much we have to sleep, with
ysr@777:                                        // respect to the work we just did, to
ysr@777:                                        // meet the marking overhead goal
ysr@777:   double                _marking_task_overhead; // marking target overhead for
ysr@777:                                                 // a single task
ysr@777: 
ysr@777:   // same as the two above, but for the cleanup task
ysr@777:   double                _cleanup_sleep_factor;
ysr@777:   double                _cleanup_task_overhead;
ysr@777: 
ysr@777:   // Stuff related to age cohort processing.
ysr@777:   struct ParCleanupThreadState {
ysr@777:     char _pre[64];
ysr@777:     UncleanRegionList list;
ysr@777:     char _post[64];
ysr@777:   };
ysr@777:   ParCleanupThreadState** _par_cleanup_thread_state;
ysr@777: 
ysr@777:   // CMS marking support structures
ysr@777:   CMBitMap                _markBitMap1;
ysr@777:   CMBitMap                _markBitMap2;
ysr@777:   CMBitMapRO*             _prevMarkBitMap; // completed mark bitmap
ysr@777:   CMBitMap*               _nextMarkBitMap; // under-construction mark bitmap
ysr@777:   bool                    _at_least_one_mark_complete;
ysr@777: 
ysr@777:   BitMap                  _region_bm;
ysr@777:   BitMap                  _card_bm;
ysr@777: 
ysr@777:   // Heap bounds
ysr@777:   HeapWord*               _heap_start;
ysr@777:   HeapWord*               _heap_end;
ysr@777: 
ysr@777:   // For gray objects
ysr@777:   CMMarkStack             _markStack; // Grey objects behind global finger.
ysr@777:   CMRegionStack           _regionStack; // Grey regions behind global finger.
ysr@777:   HeapWord* volatile      _finger;  // the global finger, region aligned,
ysr@777:                                     // always points to the end of the
ysr@777:                                     // last claimed region
ysr@777: 
ysr@777:   // marking tasks
ysr@777:   size_t                  _max_task_num; // maximum task number
ysr@777:   size_t                  _active_tasks; // task num currently active
ysr@777:   CMTask**                _tasks;        // task queue array (max_task_num len)
ysr@777:   CMTaskQueueSet*         _task_queues;  // task queue set
ysr@777:   ParallelTaskTerminator  _terminator;   // for termination
ysr@777: 
ysr@777:   // Two sync barriers that are used to synchronise tasks when an
ysr@777:   // overflow occurs. The algorithm is the following. All tasks enter
ysr@777:   // the first one to ensure that they have all stopped manipulating
ysr@777:   // the global data structures. After they exit it, they re-initialise
ysr@777:   // their data structures and task 0 re-initialises the global data
ysr@777:   // structures. Then, they enter the second sync barrier. This
ysr@777:   // ensure, that no task starts doing work before all data
ysr@777:   // structures (local and global) have been re-initialised. When they
ysr@777:   // exit it, they are free to start working again.
ysr@777:   WorkGangBarrierSync     _first_overflow_barrier_sync;
ysr@777:   WorkGangBarrierSync     _second_overflow_barrier_sync;
ysr@777: 
ysr@777: 
ysr@777:   // this is set by any task, when an overflow on the global data
ysr@777:   // structures is detected.
ysr@777:   volatile bool           _has_overflown;
ysr@777:   // true: marking is concurrent, false: we're in remark
ysr@777:   volatile bool           _concurrent;
ysr@777:   // set at the end of a Full GC so that marking aborts
ysr@777:   volatile bool           _has_aborted;
ysr@777:   // used when remark aborts due to an overflow to indicate that
ysr@777:   // another concurrent marking phase should start
ysr@777:   volatile bool           _restart_for_overflow;
ysr@777: 
ysr@777:   // This is true from the very start of concurrent marking until the
ysr@777:   // point when all the tasks complete their work. It is really used
ysr@777:   // to determine the points between the end of concurrent marking and
ysr@777:   // time of remark.
ysr@777:   volatile bool           _concurrent_marking_in_progress;
ysr@777: 
ysr@777:   // verbose level
ysr@777:   CMVerboseLevel          _verbose_level;
ysr@777: 
ysr@777:   // These two fields are used to implement the optimisation that
ysr@777:   // avoids pushing objects on the global/region stack if there are
ysr@777:   // no collection set regions above the lowest finger.
ysr@777: 
ysr@777:   // This is the lowest finger (among the global and local fingers),
ysr@777:   // which is calculated before a new collection set is chosen.
ysr@777:   HeapWord* _min_finger;
ysr@777:   // If this flag is true, objects/regions that are marked below the
ysr@777:   // finger should be pushed on the stack(s). If this is flag is
ysr@777:   // false, it is safe not to push them on the stack(s).
ysr@777:   bool      _should_gray_objects;
ysr@777: 
ysr@777:   // All of these times are in ms.
ysr@777:   NumberSeq _init_times;
ysr@777:   NumberSeq _remark_times;
ysr@777:   NumberSeq   _remark_mark_times;
ysr@777:   NumberSeq   _remark_weak_ref_times;
ysr@777:   NumberSeq _cleanup_times;
ysr@777:   double    _total_counting_time;
ysr@777:   double    _total_rs_scrub_time;
ysr@777: 
ysr@777:   double*   _accum_task_vtime;   // accumulated task vtime
ysr@777: 
ysr@777:   WorkGang* _parallel_workers;
ysr@777: 
ysr@777:   void weakRefsWork(bool clear_all_soft_refs);
ysr@777: 
ysr@777:   void swapMarkBitMaps();
ysr@777: 
ysr@777:   // It resets the global marking data structures, as well as the
ysr@777:   // task local ones; should be called during initial mark.
ysr@777:   void reset();
ysr@777:   // It resets all the marking data structures.
ysr@777:   void clear_marking_state();
ysr@777: 
ysr@777:   // It should be called to indicate which phase we're in (concurrent
ysr@777:   // mark or remark) and how many threads are currently active.
ysr@777:   void set_phase(size_t active_tasks, bool concurrent);
ysr@777:   // We do this after we're done with marking so that the marking data
ysr@777:   // structures are initialised to a sensible and predictable state.
ysr@777:   void set_non_marking_state();
ysr@777: 
ysr@777:   // prints all gathered CM-related statistics
ysr@777:   void print_stats();
ysr@777: 
ysr@777:   // accessor methods
ysr@777:   size_t parallel_marking_threads() { return _parallel_marking_threads; }
ysr@777:   double sleep_factor()             { return _sleep_factor; }
ysr@777:   double marking_task_overhead()    { return _marking_task_overhead;}
ysr@777:   double cleanup_sleep_factor()     { return _cleanup_sleep_factor; }
ysr@777:   double cleanup_task_overhead()    { return _cleanup_task_overhead;}
ysr@777: 
ysr@777:   HeapWord*               finger()        { return _finger;   }
ysr@777:   bool                    concurrent()    { return _concurrent; }
ysr@777:   size_t                  active_tasks()  { return _active_tasks; }
ysr@777:   ParallelTaskTerminator* terminator()    { return &_terminator; }
ysr@777: 
ysr@777:   // It claims the next available region to be scanned by a marking
ysr@777:   // task. It might return NULL if the next region is empty or we have
ysr@777:   // run out of regions. In the latter case, out_of_regions()
ysr@777:   // determines whether we've really run out of regions or the task
ysr@777:   // should call claim_region() again.  This might seem a bit
ysr@777:   // awkward. Originally, the code was written so that claim_region()
ysr@777:   // either successfully returned with a non-empty region or there
ysr@777:   // were no more regions to be claimed. The problem with this was
ysr@777:   // that, in certain circumstances, it iterated over large chunks of
ysr@777:   // the heap finding only empty regions and, while it was working, it
ysr@777:   // was preventing the calling task to call its regular clock
ysr@777:   // method. So, this way, each task will spend very little time in
ysr@777:   // claim_region() and is allowed to call the regular clock method
ysr@777:   // frequently.
ysr@777:   HeapRegion* claim_region(int task);
ysr@777: 
ysr@777:   // It determines whether we've run out of regions to scan.
ysr@777:   bool        out_of_regions() { return _finger == _heap_end; }
ysr@777: 
ysr@777:   // Returns the task with the given id
ysr@777:   CMTask* task(int id) {
ysr@777:     guarantee( 0 <= id && id < (int) _active_tasks, "task id not within "
ysr@777:                "active bounds" );
ysr@777:     return _tasks[id];
ysr@777:   }
ysr@777: 
ysr@777:   // Returns the task queue with the given id
ysr@777:   CMTaskQueue* task_queue(int id) {
ysr@777:     guarantee( 0 <= id && id < (int) _active_tasks, "task queue id not within "
ysr@777:                "active bounds" );
ysr@777:     return (CMTaskQueue*) _task_queues->queue(id);
ysr@777:   }
ysr@777: 
ysr@777:   // Returns the task queue set
ysr@777:   CMTaskQueueSet* task_queues()  { return _task_queues; }
ysr@777: 
ysr@777:   // Access / manipulation of the overflow flag which is set to
ysr@777:   // indicate that the global stack or region stack has overflown
ysr@777:   bool has_overflown()           { return _has_overflown; }
ysr@777:   void set_has_overflown()       { _has_overflown = true; }
ysr@777:   void clear_has_overflown()     { _has_overflown = false; }
ysr@777: 
ysr@777:   bool has_aborted()             { return _has_aborted; }
ysr@777:   bool restart_for_overflow()    { return _restart_for_overflow; }
ysr@777: 
ysr@777:   // Methods to enter the two overflow sync barriers
ysr@777:   void enter_first_sync_barrier(int task_num);
ysr@777:   void enter_second_sync_barrier(int task_num);
ysr@777: 
ysr@777: public:
ysr@777:   // Manipulation of the global mark stack.
ysr@777:   // Notice that the first mark_stack_push is CAS-based, whereas the
ysr@777:   // two below are Mutex-based. This is OK since the first one is only
ysr@777:   // called during evacuation pauses and doesn't compete with the
ysr@777:   // other two (which are called by the marking tasks during
ysr@777:   // concurrent marking or remark).
ysr@777:   bool mark_stack_push(oop p) {
ysr@777:     _markStack.par_push(p);
ysr@777:     if (_markStack.overflow()) {
ysr@777:       set_has_overflown();
ysr@777:       return false;
ysr@777:     }
ysr@777:     return true;
ysr@777:   }
ysr@777:   bool mark_stack_push(oop* arr, int n) {
ysr@777:     _markStack.par_push_arr(arr, n);
ysr@777:     if (_markStack.overflow()) {
ysr@777:       set_has_overflown();
ysr@777:       return false;
ysr@777:     }
ysr@777:     return true;
ysr@777:   }
ysr@777:   void mark_stack_pop(oop* arr, int max, int* n) {
ysr@777:     _markStack.par_pop_arr(arr, max, n);
ysr@777:   }
ysr@777:   size_t mark_stack_size()              { return _markStack.size(); }
ysr@777:   size_t partial_mark_stack_size_target() { return _markStack.maxElems()/3; }
ysr@777:   bool mark_stack_overflow()            { return _markStack.overflow(); }
ysr@777:   bool mark_stack_empty()               { return _markStack.isEmpty(); }
ysr@777: 
ysr@777:   // Manipulation of the region stack
ysr@777:   bool region_stack_push(MemRegion mr) {
ysr@777:     _regionStack.push(mr);
ysr@777:     if (_regionStack.overflow()) {
ysr@777:       set_has_overflown();
ysr@777:       return false;
ysr@777:     }
ysr@777:     return true;
ysr@777:   }
ysr@777:   MemRegion region_stack_pop()          { return _regionStack.pop(); }
ysr@777:   int region_stack_size()               { return _regionStack.size(); }
ysr@777:   bool region_stack_overflow()          { return _regionStack.overflow(); }
ysr@777:   bool region_stack_empty()             { return _regionStack.isEmpty(); }
ysr@777: 
ysr@777:   bool concurrent_marking_in_progress() {
ysr@777:     return _concurrent_marking_in_progress;
ysr@777:   }
ysr@777:   void set_concurrent_marking_in_progress() {
ysr@777:     _concurrent_marking_in_progress = true;
ysr@777:   }
ysr@777:   void clear_concurrent_marking_in_progress() {
ysr@777:     _concurrent_marking_in_progress = false;
ysr@777:   }
ysr@777: 
ysr@777:   void update_accum_task_vtime(int i, double vtime) {
ysr@777:     _accum_task_vtime[i] += vtime;
ysr@777:   }
ysr@777: 
ysr@777:   double all_task_accum_vtime() {
ysr@777:     double ret = 0.0;
ysr@777:     for (int i = 0; i < (int)_max_task_num; ++i)
ysr@777:       ret += _accum_task_vtime[i];
ysr@777:     return ret;
ysr@777:   }
ysr@777: 
ysr@777:   // Attempts to steal an object from the task queues of other tasks
ysr@777:   bool try_stealing(int task_num, int* hash_seed, oop& obj) {
ysr@777:     return _task_queues->steal(task_num, hash_seed, obj);
ysr@777:   }
ysr@777: 
ysr@777:   // It grays an object by first marking it. Then, if it's behind the
ysr@777:   // global finger, it also pushes it on the global stack.
ysr@777:   void deal_with_reference(oop obj);
ysr@777: 
ysr@777:   ConcurrentMark(ReservedSpace rs, int max_regions);
ysr@777:   ~ConcurrentMark();
ysr@777:   ConcurrentMarkThread* cmThread() { return _cmThread; }
ysr@777: 
ysr@777:   CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; }
ysr@777:   CMBitMap*   nextMarkBitMap() const { return _nextMarkBitMap; }
ysr@777: 
ysr@777:   // The following three are interaction between CM and
ysr@777:   // G1CollectedHeap
ysr@777: 
ysr@777:   // This notifies CM that a root during initial-mark needs to be
ysr@777:   // grayed and it's MT-safe. Currently, we just mark it. But, in the
ysr@777:   // future, we can experiment with pushing it on the stack and we can
ysr@777:   // do this without changing G1CollectedHeap.
ysr@777:   void grayRoot(oop p);
ysr@777:   // It's used during evacuation pauses to gray a region, if
ysr@777:   // necessary, and it's MT-safe. It assumes that the caller has
ysr@777:   // marked any objects on that region. If _should_gray_objects is
ysr@777:   // true and we're still doing concurrent marking, the region is
ysr@777:   // pushed on the region stack, if it is located below the global
ysr@777:   // finger, otherwise we do nothing.
ysr@777:   void grayRegionIfNecessary(MemRegion mr);
ysr@777:   // It's used during evacuation pauses to mark and, if necessary,
ysr@777:   // gray a single object and it's MT-safe. It assumes the caller did
ysr@777:   // not mark the object. If _should_gray_objects is true and we're
ysr@777:   // still doing concurrent marking, the objects is pushed on the
ysr@777:   // global stack, if it is located below the global finger, otherwise
ysr@777:   // we do nothing.
ysr@777:   void markAndGrayObjectIfNecessary(oop p);
ysr@777: 
ysr@777:   // This iterates over the bitmap of the previous marking and prints
ysr@777:   // out all objects that are marked on the bitmap and indicates
ysr@777:   // whether what they point to is also marked or not.
ysr@777:   void print_prev_bitmap_reachable();
ysr@777: 
ysr@777:   // Clear the next marking bitmap (will be called concurrently).
ysr@777:   void clearNextBitmap();
ysr@777: 
ysr@777:   // main CMS steps and related support
ysr@777:   void checkpointRootsInitial();
ysr@777: 
ysr@777:   // These two do the work that needs to be done before and after the
ysr@777:   // initial root checkpoint. Since this checkpoint can be done at two
ysr@777:   // different points (i.e. an explicit pause or piggy-backed on a
ysr@777:   // young collection), then it's nice to be able to easily share the
ysr@777:   // pre/post code. It might be the case that we can put everything in
ysr@777:   // the post method. TP
ysr@777:   void checkpointRootsInitialPre();
ysr@777:   void checkpointRootsInitialPost();
ysr@777: 
ysr@777:   // Do concurrent phase of marking, to a tentative transitive closure.
ysr@777:   void markFromRoots();
ysr@777: 
ysr@777:   // Process all unprocessed SATB buffers. It is called at the
ysr@777:   // beginning of an evacuation pause.
ysr@777:   void drainAllSATBBuffers();
ysr@777: 
ysr@777:   void checkpointRootsFinal(bool clear_all_soft_refs);
ysr@777:   void checkpointRootsFinalWork();
ysr@777:   void calcDesiredRegions();
ysr@777:   void cleanup();
ysr@777:   void completeCleanup();
ysr@777: 
ysr@777:   // Mark in the previous bitmap.  NB: this is usually read-only, so use
ysr@777:   // this carefully!
ysr@777:   void markPrev(oop p);
ysr@777:   void clear(oop p);
ysr@777:   // Clears marks for all objects in the given range, for both prev and
ysr@777:   // next bitmaps.  NB: the previous bitmap is usually read-only, so use
ysr@777:   // this carefully!
ysr@777:   void clearRangeBothMaps(MemRegion mr);
ysr@777: 
ysr@777:   // Record the current top of the mark and region stacks; a
ysr@777:   // subsequent oops_do() on the mark stack and
ysr@777:   // invalidate_entries_into_cset() on the region stack will iterate
ysr@777:   // only over indices valid at the time of this call.
ysr@777:   void set_oops_do_bound() {
ysr@777:     _markStack.set_oops_do_bound();
ysr@777:     _regionStack.set_oops_do_bound();
ysr@777:   }
ysr@777:   // Iterate over the oops in the mark stack and all local queues. It
ysr@777:   // also calls invalidate_entries_into_cset() on the region stack.
ysr@777:   void oops_do(OopClosure* f);
ysr@777:   // It is called at the end of an evacuation pause during marking so
ysr@777:   // that CM is notified of where the new end of the heap is. It
ysr@777:   // doesn't do anything if concurrent_marking_in_progress() is false,
ysr@777:   // unless the force parameter is true.
ysr@777:   void update_g1_committed(bool force = false);
ysr@777: 
ysr@777:   void complete_marking_in_collection_set();
ysr@777: 
ysr@777:   // It indicates that a new collection set is being chosen.
ysr@777:   void newCSet();
ysr@777:   // It registers a collection set heap region with CM. This is used
ysr@777:   // to determine whether any heap regions are located above the finger.
ysr@777:   void registerCSetRegion(HeapRegion* hr);
ysr@777: 
ysr@777:   // Returns "true" if at least one mark has been completed.
ysr@777:   bool at_least_one_mark_complete() { return _at_least_one_mark_complete; }
ysr@777: 
ysr@777:   bool isMarked(oop p) const {
ysr@777:     assert(p != NULL && p->is_oop(), "expected an oop");
ysr@777:     HeapWord* addr = (HeapWord*)p;
ysr@777:     assert(addr >= _nextMarkBitMap->startWord() ||
ysr@777:            addr < _nextMarkBitMap->endWord(), "in a region");
ysr@777: 
ysr@777:     return _nextMarkBitMap->isMarked(addr);
ysr@777:   }
ysr@777: 
ysr@777:   inline bool not_yet_marked(oop p) const;
ysr@777: 
ysr@777:   // XXX Debug code
ysr@777:   bool containing_card_is_marked(void* p);
ysr@777:   bool containing_cards_are_marked(void* start, void* last);
ysr@777: 
ysr@777:   bool isPrevMarked(oop p) const {
ysr@777:     assert(p != NULL && p->is_oop(), "expected an oop");
ysr@777:     HeapWord* addr = (HeapWord*)p;
ysr@777:     assert(addr >= _prevMarkBitMap->startWord() ||
ysr@777:            addr < _prevMarkBitMap->endWord(), "in a region");
ysr@777: 
ysr@777:     return _prevMarkBitMap->isMarked(addr);
ysr@777:   }
ysr@777: 
ysr@777:   inline bool do_yield_check(int worker_i = 0);
ysr@777:   inline bool should_yield();
ysr@777: 
ysr@777:   // Called to abort the marking cycle after a Full GC takes palce.
ysr@777:   void abort();
ysr@777: 
ysr@777:   // This prints the global/local fingers. It is used for debugging.
ysr@777:   NOT_PRODUCT(void print_finger();)
ysr@777: 
ysr@777:   void print_summary_info();
ysr@777: 
ysr@777:   // The following indicate whether a given verbose level has been
ysr@777:   // set. Notice that anything above stats is conditional to
ysr@777:   // _MARKING_VERBOSE_ having been set to 1
ysr@777:   bool verbose_stats()
ysr@777:     { return _verbose_level >= stats_verbose; }
ysr@777:   bool verbose_low()
ysr@777:     { return _MARKING_VERBOSE_ && _verbose_level >= low_verbose; }
ysr@777:   bool verbose_medium()
ysr@777:     { return _MARKING_VERBOSE_ && _verbose_level >= medium_verbose; }
ysr@777:   bool verbose_high()
ysr@777:     { return _MARKING_VERBOSE_ && _verbose_level >= high_verbose; }
ysr@777: };
ysr@777: 
ysr@777: // A class representing a marking task.
ysr@777: class CMTask : public TerminatorTerminator {
ysr@777: private:
ysr@777:   enum PrivateConstants {
ysr@777:     // the regular clock call is called once the scanned words reaches
ysr@777:     // this limit
ysr@777:     words_scanned_period          = 12*1024,
ysr@777:     // the regular clock call is called once the number of visited
ysr@777:     // references reaches this limit
ysr@777:     refs_reached_period           = 384,
ysr@777:     // initial value for the hash seed, used in the work stealing code
ysr@777:     init_hash_seed                = 17,
ysr@777:     // how many entries will be transferred between global stack and
ysr@777:     // local queues
ysr@777:     global_stack_transfer_size    = 16
ysr@777:   };
ysr@777: 
ysr@777:   int                         _task_id;
ysr@777:   G1CollectedHeap*            _g1h;
ysr@777:   ConcurrentMark*             _cm;
ysr@777:   CMBitMap*                   _nextMarkBitMap;
ysr@777:   // the task queue of this task
ysr@777:   CMTaskQueue*                _task_queue;
ysr@1280: private:
ysr@777:   // the task queue set---needed for stealing
ysr@777:   CMTaskQueueSet*             _task_queues;
ysr@777:   // indicates whether the task has been claimed---this is only  for
ysr@777:   // debugging purposes
ysr@777:   bool                        _claimed;
ysr@777: 
ysr@777:   // number of calls to this task
ysr@777:   int                         _calls;
ysr@777: 
ysr@777:   // when the virtual timer reaches this time, the marking step should
ysr@777:   // exit
ysr@777:   double                      _time_target_ms;
ysr@777:   // the start time of the current marking step
ysr@777:   double                      _start_time_ms;
ysr@777: 
ysr@777:   // the oop closure used for iterations over oops
ysr@777:   OopClosure*                 _oop_closure;
ysr@777: 
ysr@777:   // the region this task is scanning, NULL if we're not scanning any
ysr@777:   HeapRegion*                 _curr_region;
ysr@777:   // the local finger of this task, NULL if we're not scanning a region
ysr@777:   HeapWord*                   _finger;
ysr@777:   // limit of the region this task is scanning, NULL if we're not scanning one
ysr@777:   HeapWord*                   _region_limit;
ysr@777: 
ysr@777:   // This is used only when we scan regions popped from the region
ysr@777:   // stack. It records what the last object on such a region we
ysr@777:   // scanned was. It is used to ensure that, if we abort region
ysr@777:   // iteration, we do not rescan the first part of the region. This
ysr@777:   // should be NULL when we're not scanning a region from the region
ysr@777:   // stack.
ysr@777:   HeapWord*                   _region_finger;
ysr@777: 
ysr@777:   // the number of words this task has scanned
ysr@777:   size_t                      _words_scanned;
ysr@777:   // When _words_scanned reaches this limit, the regular clock is
ysr@777:   // called. Notice that this might be decreased under certain
ysr@777:   // circumstances (i.e. when we believe that we did an expensive
ysr@777:   // operation).
ysr@777:   size_t                      _words_scanned_limit;
ysr@777:   // the initial value of _words_scanned_limit (i.e. what it was
ysr@777:   // before it was decreased).
ysr@777:   size_t                      _real_words_scanned_limit;
ysr@777: 
ysr@777:   // the number of references this task has visited
ysr@777:   size_t                      _refs_reached;
ysr@777:   // When _refs_reached reaches this limit, the regular clock is
ysr@777:   // called. Notice this this might be decreased under certain
ysr@777:   // circumstances (i.e. when we believe that we did an expensive
ysr@777:   // operation).
ysr@777:   size_t                      _refs_reached_limit;
ysr@777:   // the initial value of _refs_reached_limit (i.e. what it was before
ysr@777:   // it was decreased).
ysr@777:   size_t                      _real_refs_reached_limit;
ysr@777: 
ysr@777:   // used by the work stealing stuff
ysr@777:   int                         _hash_seed;
ysr@777:   // if this is true, then the task has aborted for some reason
ysr@777:   bool                        _has_aborted;
ysr@777:   // set when the task aborts because it has met its time quota
ysr@777:   bool                        _has_aborted_timed_out;
ysr@777:   // true when we're draining SATB buffers; this avoids the task
ysr@777:   // aborting due to SATB buffers being available (as we're already
ysr@777:   // dealing with them)
ysr@777:   bool                        _draining_satb_buffers;
ysr@777: 
ysr@777:   // number sequence of past step times
ysr@777:   NumberSeq                   _step_times_ms;
ysr@777:   // elapsed time of this task
ysr@777:   double                      _elapsed_time_ms;
ysr@777:   // termination time of this task
ysr@777:   double                      _termination_time_ms;
ysr@777:   // when this task got into the termination protocol
ysr@777:   double                      _termination_start_time_ms;
ysr@777: 
ysr@777:   // true when the task is during a concurrent phase, false when it is
ysr@777:   // in the remark phase (so, in the latter case, we do not have to
ysr@777:   // check all the things that we have to check during the concurrent
ysr@777:   // phase, i.e. SATB buffer availability...)
ysr@777:   bool                        _concurrent;
ysr@777: 
ysr@777:   TruncatedSeq                _marking_step_diffs_ms;
ysr@777: 
ysr@777:   // LOTS of statistics related with this task
ysr@777: #if _MARKING_STATS_
ysr@777:   NumberSeq                   _all_clock_intervals_ms;
ysr@777:   double                      _interval_start_time_ms;
ysr@777: 
ysr@777:   int                         _aborted;
ysr@777:   int                         _aborted_overflow;
ysr@777:   int                         _aborted_cm_aborted;
ysr@777:   int                         _aborted_yield;
ysr@777:   int                         _aborted_timed_out;
ysr@777:   int                         _aborted_satb;
ysr@777:   int                         _aborted_termination;
ysr@777: 
ysr@777:   int                         _steal_attempts;
ysr@777:   int                         _steals;
ysr@777: 
ysr@777:   int                         _clock_due_to_marking;
ysr@777:   int                         _clock_due_to_scanning;
ysr@777: 
ysr@777:   int                         _local_pushes;
ysr@777:   int                         _local_pops;
ysr@777:   int                         _local_max_size;
ysr@777:   int                         _objs_scanned;
ysr@777: 
ysr@777:   int                         _global_pushes;
ysr@777:   int                         _global_pops;
ysr@777:   int                         _global_max_size;
ysr@777: 
ysr@777:   int                         _global_transfers_to;
ysr@777:   int                         _global_transfers_from;
ysr@777: 
ysr@777:   int                         _region_stack_pops;
ysr@777: 
ysr@777:   int                         _regions_claimed;
ysr@777:   int                         _objs_found_on_bitmap;
ysr@777: 
ysr@777:   int                         _satb_buffers_processed;
ysr@777: #endif // _MARKING_STATS_
ysr@777: 
ysr@777:   // it updates the local fields after this task has claimed
ysr@777:   // a new region to scan
ysr@777:   void setup_for_region(HeapRegion* hr);
ysr@777:   // it brings up-to-date the limit of the region
ysr@777:   void update_region_limit();
ysr@777:   // it resets the local fields after a task has finished scanning a
ysr@777:   // region
ysr@777:   void giveup_current_region();
ysr@777: 
ysr@777:   // called when either the words scanned or the refs visited limit
ysr@777:   // has been reached
ysr@777:   void reached_limit();
ysr@777:   // recalculates the words scanned and refs visited limits
ysr@777:   void recalculate_limits();
ysr@777:   // decreases the words scanned and refs visited limits when we reach
ysr@777:   // an expensive operation
ysr@777:   void decrease_limits();
ysr@777:   // it checks whether the words scanned or refs visited reached their
ysr@777:   // respective limit and calls reached_limit() if they have
ysr@777:   void check_limits() {
ysr@777:     if (_words_scanned >= _words_scanned_limit ||
ysr@777:         _refs_reached >= _refs_reached_limit)
ysr@777:       reached_limit();
ysr@777:   }
ysr@777:   // this is supposed to be called regularly during a marking step as
ysr@777:   // it checks a bunch of conditions that might cause the marking step
ysr@777:   // to abort
ysr@777:   void regular_clock_call();
ysr@777:   bool concurrent() { return _concurrent; }
ysr@777: 
ysr@777: public:
ysr@777:   // It resets the task; it should be called right at the beginning of
ysr@777:   // a marking phase.
ysr@777:   void reset(CMBitMap* _nextMarkBitMap);
ysr@777:   // it clears all the fields that correspond to a claimed region.
ysr@777:   void clear_region_fields();
ysr@777: 
ysr@777:   void set_concurrent(bool concurrent) { _concurrent = concurrent; }
ysr@777: 
ysr@777:   // The main method of this class which performs a marking step
ysr@777:   // trying not to exceed the given duration. However, it might exit
ysr@777:   // prematurely, according to some conditions (i.e. SATB buffers are
ysr@777:   // available for processing).
ysr@777:   void do_marking_step(double target_ms);
ysr@777: 
ysr@777:   // These two calls start and stop the timer
ysr@777:   void record_start_time() {
ysr@777:     _elapsed_time_ms = os::elapsedTime() * 1000.0;
ysr@777:   }
ysr@777:   void record_end_time() {
ysr@777:     _elapsed_time_ms = os::elapsedTime() * 1000.0 - _elapsed_time_ms;
ysr@777:   }
ysr@777: 
ysr@777:   // returns the task ID
ysr@777:   int task_id() { return _task_id; }
ysr@777: 
ysr@777:   // From TerminatorTerminator. It determines whether this task should
ysr@777:   // exit the termination protocol after it's entered it.
ysr@777:   virtual bool should_exit_termination();
ysr@777: 
ysr@777:   HeapWord* finger()            { return _finger; }
ysr@777: 
ysr@777:   bool has_aborted()            { return _has_aborted; }
ysr@777:   void set_has_aborted()        { _has_aborted = true; }
ysr@777:   void clear_has_aborted()      { _has_aborted = false; }
ysr@777:   bool claimed() { return _claimed; }
ysr@777: 
ysr@777:   void set_oop_closure(OopClosure* oop_closure) {
ysr@777:     _oop_closure = oop_closure;
ysr@777:   }
ysr@777: 
ysr@777:   // It grays the object by marking it and, if necessary, pushing it
ysr@777:   // on the local queue
ysr@777:   void deal_with_reference(oop obj);
ysr@777: 
ysr@777:   // It scans an object and visits its children.
ysr@777:   void scan_object(oop obj) {
ysr@777:     tmp_guarantee_CM( _nextMarkBitMap->isMarked((HeapWord*) obj),
ysr@777:                       "invariant" );
ysr@777: 
ysr@777:     if (_cm->verbose_high())
ysr@777:       gclog_or_tty->print_cr("[%d] we're scanning object "PTR_FORMAT,
ysr@777:                              _task_id, (void*) obj);
ysr@777: 
ysr@777:     size_t obj_size = obj->size();
ysr@777:     _words_scanned += obj_size;
ysr@777: 
ysr@777:     obj->oop_iterate(_oop_closure);
ysr@777:     statsOnly( ++_objs_scanned );
ysr@777:     check_limits();
ysr@777:   }
ysr@777: 
ysr@777:   // It pushes an object on the local queue.
ysr@777:   void push(oop obj);
ysr@777: 
ysr@777:   // These two move entries to/from the global stack.
ysr@777:   void move_entries_to_global_stack();
ysr@777:   void get_entries_from_global_stack();
ysr@777: 
ysr@777:   // It pops and scans objects from the local queue. If partially is
ysr@777:   // true, then it stops when the queue size is of a given limit. If
ysr@777:   // partially is false, then it stops when the queue is empty.
ysr@777:   void drain_local_queue(bool partially);
ysr@777:   // It moves entries from the global stack to the local queue and
ysr@777:   // drains the local queue. If partially is true, then it stops when
ysr@777:   // both the global stack and the local queue reach a given size. If
ysr@777:   // partially if false, it tries to empty them totally.
ysr@777:   void drain_global_stack(bool partially);
ysr@777:   // It keeps picking SATB buffers and processing them until no SATB
ysr@777:   // buffers are available.
ysr@777:   void drain_satb_buffers();
ysr@777:   // It keeps popping regions from the region stack and processing
ysr@777:   // them until the region stack is empty.
ysr@777:   void drain_region_stack(BitMapClosure* closure);
ysr@777: 
ysr@777:   // moves the local finger to a new location
ysr@777:   inline void move_finger_to(HeapWord* new_finger) {
ysr@777:     tmp_guarantee_CM( new_finger >= _finger && new_finger < _region_limit,
ysr@777:                    "invariant" );
ysr@777:     _finger = new_finger;
ysr@777:   }
ysr@777: 
ysr@777:   // moves the region finger to a new location
ysr@777:   inline void move_region_finger_to(HeapWord* new_finger) {
ysr@777:     tmp_guarantee_CM( new_finger < _cm->finger(), "invariant" );
ysr@777:     _region_finger = new_finger;
ysr@777:   }
ysr@777: 
ysr@777:   CMTask(int task_num, ConcurrentMark *cm,
ysr@777:          CMTaskQueue* task_queue, CMTaskQueueSet* task_queues);
ysr@777: 
ysr@777:   // it prints statistics associated with this task
ysr@777:   void print_stats();
ysr@777: 
ysr@777: #if _MARKING_STATS_
ysr@777:   void increase_objs_found_on_bitmap() { ++_objs_found_on_bitmap; }
ysr@777: #endif // _MARKING_STATS_
ysr@777: };