truffle: src/share/vm/gc_implementation/g1/concurrentMark.hpp comparison

comparison src/share/vm/gc_implementation/g1/concurrentMark.hpp @ 362:f8199438385b

Merge

author	apetrusenko
date	Wed, 17 Sep 2008 16:49:18 +0400
parents	37f87013dfd8
children	fe3d7c11b4b7

comparison

equal deleted inserted replaced

-:5fa96a5a7e76
+:f8199438385b
+/*
+* Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+class G1CollectedHeap;
+class CMTask;
+typedef GenericTaskQueue<oop> CMTaskQueue;
+typedef GenericTaskQueueSet<oop> CMTaskQueueSet;
+// A generic CM bit map.  This is essentially a wrapper around the BitMap
+// class, with one bit per (1<<_shifter) HeapWords.
+class CMBitMapRO {
+protected:
+HeapWord* _bmStartWord;      // base address of range covered by map
+size_t    _bmWordSize;       // map size (in #HeapWords covered)
+const int _shifter;          // map to char or bit
+VirtualSpace _virtual_space; // underlying the bit map
+BitMap    _bm;               // the bit map itself
+public:
+// constructor
+CMBitMapRO(ReservedSpace rs, int shifter);
+enum { do_yield = true };
+// inquiries
+HeapWord* startWord()   const { return _bmStartWord; }
+size_t    sizeInWords() const { return _bmWordSize;  }
+// the following is one past the last word in space
+HeapWord* endWord()     const { return _bmStartWord + _bmWordSize; }
+// read marks
+bool isMarked(HeapWord* addr) const {
+assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+"outside underlying space?");
+return _bm.at(heapWordToOffset(addr));
+}
+// iteration
+bool iterate(BitMapClosure* cl) { return _bm.iterate(cl); }
+bool iterate(BitMapClosure* cl, MemRegion mr);
+// Return the address corresponding to the next marked bit at or after
+// "addr", and before "limit", if "limit" is non-NULL.  If there is no
+// such bit, returns "limit" if that is non-NULL, or else "endWord()".
+HeapWord* getNextMarkedWordAddress(HeapWord* addr,
+HeapWord* limit = NULL) const;
+// Return the address corresponding to the next unmarked bit at or after
+// "addr", and before "limit", if "limit" is non-NULL.  If there is no
+// such bit, returns "limit" if that is non-NULL, or else "endWord()".
+HeapWord* getNextUnmarkedWordAddress(HeapWord* addr,
+HeapWord* limit = NULL) const;
+// conversion utilities
+// XXX Fix these so that offsets are size_t's...
+HeapWord* offsetToHeapWord(size_t offset) const {
+return _bmStartWord + (offset << _shifter);
+}
+size_t heapWordToOffset(HeapWord* addr) const {
+return pointer_delta(addr, _bmStartWord) >> _shifter;
+}
+int heapWordDiffToOffsetDiff(size_t diff) const;
+HeapWord* nextWord(HeapWord* addr) {
+return offsetToHeapWord(heapWordToOffset(addr) + 1);
+}
+void mostly_disjoint_range_union(BitMap*   from_bitmap,
+size_t    from_start_index,
+HeapWord* to_start_word,
+size_t    word_num);
+// debugging
+NOT_PRODUCT(bool covers(ReservedSpace rs) const;)
+};
+class CMBitMap : public CMBitMapRO {
+public:
+// constructor
+CMBitMap(ReservedSpace rs, int shifter) :
+CMBitMapRO(rs, shifter) {}
+// write marks
+void mark(HeapWord* addr) {
+assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+"outside underlying space?");
+_bm.at_put(heapWordToOffset(addr), true);
+}
+void clear(HeapWord* addr) {
+assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+"outside underlying space?");
+_bm.at_put(heapWordToOffset(addr), false);
+}
+bool parMark(HeapWord* addr) {
+assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+"outside underlying space?");
+return _bm.par_at_put(heapWordToOffset(addr), true);
+}
+bool parClear(HeapWord* addr) {
+assert(_bmStartWord <= addr && addr < (_bmStartWord + _bmWordSize),
+"outside underlying space?");
+return _bm.par_at_put(heapWordToOffset(addr), false);
+}
+void markRange(MemRegion mr);
+void clearAll();
+void clearRange(MemRegion mr);
+// Starting at the bit corresponding to "addr" (inclusive), find the next
+// "1" bit, if any.  This bit starts some run of consecutive "1"'s; find
+// the end of this run (stopping at "end_addr").  Return the MemRegion
+// covering from the start of the region corresponding to the first bit
+// of the run to the end of the region corresponding to the last bit of
+// the run.  If there is no "1" bit at or after "addr", return an empty
+// MemRegion.
+MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr);
+};
+// Represents a marking stack used by the CM collector.
+// Ideally this should be GrowableArray<> just like MSC's marking stack(s).
+class CMMarkStack {
+ConcurrentMark* _cm;
+oop*   _base;      // bottom of stack
+jint   _index;     // one more than last occupied index
+jint   _capacity;  // max #elements
+jint   _oops_do_bound;  // Number of elements to include in next iteration.
+NOT_PRODUCT(jint _max_depth;)  // max depth plumbed during run
+bool   _overflow;
+DEBUG_ONLY(bool _drain_in_progress;)
+DEBUG_ONLY(bool _drain_in_progress_yields;)
+public:
+CMMarkStack(ConcurrentMark* cm);
+~CMMarkStack();
+void allocate(size_t size);
+oop pop() {
+if (!isEmpty()) {
+return _base[--_index] ;
+}
+return NULL;
+}
+// If overflow happens, don't do the push, and record the overflow.
+// *Requires* that "ptr" is already marked.
+void push(oop ptr) {
+if (isFull()) {
+// Record overflow.
+_overflow = true;
+return;
+} else {
+_base[_index++] = ptr;
+NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index));
+}
+}
+// Non-block impl.  Note: concurrency is allowed only with other
+// "par_push" operations, not with "pop" or "drain".  We would need
+// parallel versions of them if such concurrency was desired.
+void par_push(oop ptr);
+// Pushes the first "n" elements of "ptr_arr" on the stack.
+// Non-block impl.  Note: concurrency is allowed only with other
+// "par_adjoin_arr" or "push" operations, not with "pop" or "drain".
+void par_adjoin_arr(oop* ptr_arr, int n);
+// Pushes the first "n" elements of "ptr_arr" on the stack.
+// Locking impl: concurrency is allowed only with
+// "par_push_arr" and/or "par_pop_arr" operations, which use the same
+// locking strategy.
+void par_push_arr(oop* ptr_arr, int n);
+// If returns false, the array was empty.  Otherwise, removes up to "max"
+// elements from the stack, and transfers them to "ptr_arr" in an
+// unspecified order.  The actual number transferred is given in "n" ("n
+// == 0" is deliberately redundant with the return value.)  Locking impl:
+// concurrency is allowed only with "par_push_arr" and/or "par_pop_arr"
+// operations, which use the same locking strategy.
+bool par_pop_arr(oop* ptr_arr, int max, int* n);
+// Drain the mark stack, applying the given closure to all fields of
+// objects on the stack.  (That is, continue until the stack is empty,
+// even if closure applications add entries to the stack.)  The "bm"
+// argument, if non-null, may be used to verify that only marked objects
+// are on the mark stack.  If "yield_after" is "true", then the
+// concurrent marker performing the drain offers to yield after
+// processing each object.  If a yield occurs, stops the drain operation
+// and returns false.  Otherwise, returns true.
+template<class OopClosureClass>
+bool drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after = false);
+bool isEmpty()    { return _index == 0; }
+bool isFull()     { return _index == _capacity; }
+int maxElems()    { return _capacity; }
+bool overflow() { return _overflow; }
+void clear_overflow() { _overflow = false; }
+int  size() { return _index; }
+void setEmpty()   { _index = 0; clear_overflow(); }
+// Record the current size; a subsequent "oops_do" will iterate only over
+// indices valid at the time of this call.
+void set_oops_do_bound(jint bound = -1) {
+if (bound == -1) {
+_oops_do_bound = _index;
+} else {
+_oops_do_bound = bound;
+}
+}
+jint oops_do_bound() { return _oops_do_bound; }
+// iterate over the oops in the mark stack, up to the bound recorded via
+// the call above.
+void oops_do(OopClosure* f);
+};
+class CMRegionStack {
+MemRegion* _base;
+jint _capacity;
+jint _index;
+jint _oops_do_bound;
+bool _overflow;
+public:
+CMRegionStack();
+~CMRegionStack();
+void allocate(size_t size);
+// This is lock-free; assumes that it will only be called in parallel
+// with other "push" operations (no pops).
+void push(MemRegion mr);
+// Lock-free; assumes that it will only be called in parallel
+// with other "pop" operations (no pushes).
+MemRegion pop();
+bool isEmpty()    { return _index == 0; }
+bool isFull()     { return _index == _capacity; }
+bool overflow() { return _overflow; }
+void clear_overflow() { _overflow = false; }
+int  size() { return _index; }
+// It iterates over the entries in the region stack and it
+// invalidates (i.e. assigns MemRegion()) the ones that point to
+// regions in the collection set.
+bool invalidate_entries_into_cset();
+// This gives an upper bound up to which the iteration in
+// invalidate_entries_into_cset() will reach. This prevents
+// newly-added entries to be unnecessarily scanned.
+void set_oops_do_bound() {
+_oops_do_bound = _index;
+}
+void setEmpty()   { _index = 0; clear_overflow(); }
+};
+// this will enable a variety of different statistics per GC task
+#define _MARKING_STATS_       0
+// this will enable the higher verbose levels
+#define _MARKING_VERBOSE_     0
+#if _MARKING_STATS_
+#define statsOnly(statement)  \
+do {                          \
+statement ;                 \
+} while (0)
+#else // _MARKING_STATS_
+#define statsOnly(statement)  \
+do {                          \
+} while (0)
+#endif // _MARKING_STATS_
+// Some extra guarantees that I like to also enable in optimised mode
+// when debugging. If you want to enable them, comment out the assert
+// macro and uncomment out the guaratee macro
+// #define tmp_guarantee_CM(expr, str) guarantee(expr, str)
+#define tmp_guarantee_CM(expr, str) assert(expr, str)
+typedef enum {
+no_verbose  = 0,   // verbose turned off
+stats_verbose,     // only prints stats at the end of marking
+low_verbose,       // low verbose, mostly per region and per major event
+medium_verbose,    // a bit more detailed than low
+high_verbose       // per object verbose
+} CMVerboseLevel;
+class ConcurrentMarkThread;
+class ConcurrentMark {
+friend class ConcurrentMarkThread;
+friend class CMTask;
+friend class CMBitMapClosure;
+friend class CSMarkOopClosure;
+friend class CMGlobalObjectClosure;
+friend class CMRemarkTask;
+friend class CMConcurrentMarkingTask;
+friend class G1ParNoteEndTask;
+friend class CalcLiveObjectsClosure;
+protected:
+ConcurrentMarkThread* _cmThread;   // the thread doing the work
+G1CollectedHeap*      _g1h;        // the heap.
+size_t                _parallel_marking_threads; // the number of marking
+// threads we'll use
+double                _sleep_factor; // how much we have to sleep, with
+// respect to the work we just did, to
+// meet the marking overhead goal
+double                _marking_task_overhead; // marking target overhead for
+// a single task
+// same as the two above, but for the cleanup task
+double                _cleanup_sleep_factor;
+double                _cleanup_task_overhead;
+// Stuff related to age cohort processing.
+struct ParCleanupThreadState {
+char _pre[64];
+UncleanRegionList list;
+char _post[64];
+};
+ParCleanupThreadState** _par_cleanup_thread_state;
+// CMS marking support structures
+CMBitMap                _markBitMap1;
+CMBitMap                _markBitMap2;
+CMBitMapRO*             _prevMarkBitMap; // completed mark bitmap
+CMBitMap*               _nextMarkBitMap; // under-construction mark bitmap
+bool                    _at_least_one_mark_complete;
+BitMap                  _region_bm;
+BitMap                  _card_bm;
+// Heap bounds
+HeapWord*               _heap_start;
+HeapWord*               _heap_end;
+// For gray objects
+CMMarkStack             _markStack; // Grey objects behind global finger.
+CMRegionStack           _regionStack; // Grey regions behind global finger.
+HeapWord* volatile      _finger;  // the global finger, region aligned,
+// always points to the end of the
+// last claimed region
+// marking tasks
+size_t                  _max_task_num; // maximum task number
+size_t                  _active_tasks; // task num currently active
+CMTask**                _tasks;        // task queue array (max_task_num len)
+CMTaskQueueSet*         _task_queues;  // task queue set
+ParallelTaskTerminator  _terminator;   // for termination
+// Two sync barriers that are used to synchronise tasks when an
+// overflow occurs. The algorithm is the following. All tasks enter
+// the first one to ensure that they have all stopped manipulating
+// the global data structures. After they exit it, they re-initialise
+// their data structures and task 0 re-initialises the global data
+// structures. Then, they enter the second sync barrier. This
+// ensure, that no task starts doing work before all data
+// structures (local and global) have been re-initialised. When they
+// exit it, they are free to start working again.
+WorkGangBarrierSync     _first_overflow_barrier_sync;
+WorkGangBarrierSync     _second_overflow_barrier_sync;
+// this is set by any task, when an overflow on the global data
+// structures is detected.
+volatile bool           _has_overflown;
+// true: marking is concurrent, false: we're in remark
+volatile bool           _concurrent;
+// set at the end of a Full GC so that marking aborts
+volatile bool           _has_aborted;
+// used when remark aborts due to an overflow to indicate that
+// another concurrent marking phase should start
+volatile bool           _restart_for_overflow;
+// This is true from the very start of concurrent marking until the
+// point when all the tasks complete their work. It is really used
+// to determine the points between the end of concurrent marking and
+// time of remark.
+volatile bool           _concurrent_marking_in_progress;
+// verbose level
+CMVerboseLevel          _verbose_level;
+COTracker               _cleanup_co_tracker;
+// These two fields are used to implement the optimisation that
+// avoids pushing objects on the global/region stack if there are
+// no collection set regions above the lowest finger.
+// This is the lowest finger (among the global and local fingers),
+// which is calculated before a new collection set is chosen.
+HeapWord* _min_finger;
+// If this flag is true, objects/regions that are marked below the
+// finger should be pushed on the stack(s). If this is flag is
+// false, it is safe not to push them on the stack(s).
+bool      _should_gray_objects;
+// All of these times are in ms.
+NumberSeq _init_times;
+NumberSeq _remark_times;
+NumberSeq   _remark_mark_times;
+NumberSeq   _remark_weak_ref_times;
+NumberSeq _cleanup_times;
+double    _total_counting_time;
+double    _total_rs_scrub_time;
+double*   _accum_task_vtime;   // accumulated task vtime
+WorkGang* _parallel_workers;
+void weakRefsWork(bool clear_all_soft_refs);
+void swapMarkBitMaps();
+// It resets the global marking data structures, as well as the
+// task local ones; should be called during initial mark.
+void reset();
+// It resets all the marking data structures.
+void clear_marking_state();
+// It should be called to indicate which phase we're in (concurrent
+// mark or remark) and how many threads are currently active.
+void set_phase(size_t active_tasks, bool concurrent);
+// We do this after we're done with marking so that the marking data
+// structures are initialised to a sensible and predictable state.
+void set_non_marking_state();
+// prints all gathered CM-related statistics
+void print_stats();
+// accessor methods
+size_t parallel_marking_threads() { return _parallel_marking_threads; }
+double sleep_factor()             { return _sleep_factor; }
+double marking_task_overhead()    { return _marking_task_overhead;}
+double cleanup_sleep_factor()     { return _cleanup_sleep_factor; }
+double cleanup_task_overhead()    { return _cleanup_task_overhead;}
+HeapWord*               finger()        { return _finger;   }
+bool                    concurrent()    { return _concurrent; }
+size_t                  active_tasks()  { return _active_tasks; }
+ParallelTaskTerminator* terminator()    { return &_terminator; }
+// It claims the next available region to be scanned by a marking
+// task. It might return NULL if the next region is empty or we have
+// run out of regions. In the latter case, out_of_regions()
+// determines whether we've really run out of regions or the task
+// should call claim_region() again.  This might seem a bit
+// awkward. Originally, the code was written so that claim_region()
+// either successfully returned with a non-empty region or there
+// were no more regions to be claimed. The problem with this was
+// that, in certain circumstances, it iterated over large chunks of
+// the heap finding only empty regions and, while it was working, it
+// was preventing the calling task to call its regular clock
+// method. So, this way, each task will spend very little time in
+// claim_region() and is allowed to call the regular clock method
+// frequently.
+HeapRegion* claim_region(int task);
+// It determines whether we've run out of regions to scan.
+bool        out_of_regions() { return _finger == _heap_end; }
+// Returns the task with the given id
+CMTask* task(int id) {
+guarantee( 0 <= id && id < (int) _active_tasks, "task id not within "
+"active bounds" );
+return _tasks[id];
+}
+// Returns the task queue with the given id
+CMTaskQueue* task_queue(int id) {
+guarantee( 0 <= id && id < (int) _active_tasks, "task queue id not within "
+"active bounds" );
+return (CMTaskQueue*) _task_queues->queue(id);
+}
+// Returns the task queue set
+CMTaskQueueSet* task_queues()  { return _task_queues; }
+// Access / manipulation of the overflow flag which is set to
+// indicate that the global stack or region stack has overflown
+bool has_overflown()           { return _has_overflown; }
+void set_has_overflown()       { _has_overflown = true; }
+void clear_has_overflown()     { _has_overflown = false; }
+bool has_aborted()             { return _has_aborted; }
+bool restart_for_overflow()    { return _restart_for_overflow; }
+// Methods to enter the two overflow sync barriers
+void enter_first_sync_barrier(int task_num);
+void enter_second_sync_barrier(int task_num);
+public:
+// Manipulation of the global mark stack.
+// Notice that the first mark_stack_push is CAS-based, whereas the
+// two below are Mutex-based. This is OK since the first one is only
+// called during evacuation pauses and doesn't compete with the
+// other two (which are called by the marking tasks during
+// concurrent marking or remark).
+bool mark_stack_push(oop p) {
+_markStack.par_push(p);
+if (_markStack.overflow()) {
+set_has_overflown();
+return false;
+}
+return true;
+}
+bool mark_stack_push(oop* arr, int n) {
+_markStack.par_push_arr(arr, n);
+if (_markStack.overflow()) {
+set_has_overflown();
+return false;
+}
+return true;
+}
+void mark_stack_pop(oop* arr, int max, int* n) {
+_markStack.par_pop_arr(arr, max, n);
+}
+size_t mark_stack_size()              { return _markStack.size(); }
+size_t partial_mark_stack_size_target() { return _markStack.maxElems()/3; }
+bool mark_stack_overflow()            { return _markStack.overflow(); }
+bool mark_stack_empty()               { return _markStack.isEmpty(); }
+// Manipulation of the region stack
+bool region_stack_push(MemRegion mr) {
+_regionStack.push(mr);
+if (_regionStack.overflow()) {
+set_has_overflown();
+return false;
+}
+return true;
+}
+MemRegion region_stack_pop()          { return _regionStack.pop(); }
+int region_stack_size()               { return _regionStack.size(); }
+bool region_stack_overflow()          { return _regionStack.overflow(); }
+bool region_stack_empty()             { return _regionStack.isEmpty(); }
+bool concurrent_marking_in_progress() {
+return _concurrent_marking_in_progress;
+}
+void set_concurrent_marking_in_progress() {
+_concurrent_marking_in_progress = true;
+}
+void clear_concurrent_marking_in_progress() {
+_concurrent_marking_in_progress = false;
+}
+void update_accum_task_vtime(int i, double vtime) {
+_accum_task_vtime[i] += vtime;
+}
+double all_task_accum_vtime() {
+double ret = 0.0;
+for (int i = 0; i < (int)_max_task_num; ++i)
+ret += _accum_task_vtime[i];
+return ret;
+}
+// Attempts to steal an object from the task queues of other tasks
+bool try_stealing(int task_num, int* hash_seed, oop& obj) {
+return _task_queues->steal(task_num, hash_seed, obj);
+}
+// It grays an object by first marking it. Then, if it's behind the
+// global finger, it also pushes it on the global stack.
+void deal_with_reference(oop obj);
+ConcurrentMark(ReservedSpace rs, int max_regions);
+~ConcurrentMark();
+ConcurrentMarkThread* cmThread() { return _cmThread; }
+CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; }
+CMBitMap*   nextMarkBitMap() const { return _nextMarkBitMap; }
+// The following three are interaction between CM and
+// G1CollectedHeap
+// This notifies CM that a root during initial-mark needs to be
+// grayed and it's MT-safe. Currently, we just mark it. But, in the
+// future, we can experiment with pushing it on the stack and we can
+// do this without changing G1CollectedHeap.
+void grayRoot(oop p);
+// It's used during evacuation pauses to gray a region, if
+// necessary, and it's MT-safe. It assumes that the caller has
+// marked any objects on that region. If _should_gray_objects is
+// true and we're still doing concurrent marking, the region is
+// pushed on the region stack, if it is located below the global
+// finger, otherwise we do nothing.
+void grayRegionIfNecessary(MemRegion mr);
+// It's used during evacuation pauses to mark and, if necessary,
+// gray a single object and it's MT-safe. It assumes the caller did
+// not mark the object. If _should_gray_objects is true and we're
+// still doing concurrent marking, the objects is pushed on the
+// global stack, if it is located below the global finger, otherwise
+// we do nothing.
+void markAndGrayObjectIfNecessary(oop p);
+// This iterates over the bitmap of the previous marking and prints
+// out all objects that are marked on the bitmap and indicates
+// whether what they point to is also marked or not.
+void print_prev_bitmap_reachable();
+// Clear the next marking bitmap (will be called concurrently).
+void clearNextBitmap();
+// main CMS steps and related support
+void checkpointRootsInitial();
+// These two do the work that needs to be done before and after the
+// initial root checkpoint. Since this checkpoint can be done at two
+// different points (i.e. an explicit pause or piggy-backed on a
+// young collection), then it's nice to be able to easily share the
+// pre/post code. It might be the case that we can put everything in
+// the post method. TP
+void checkpointRootsInitialPre();
+void checkpointRootsInitialPost();
+// Do concurrent phase of marking, to a tentative transitive closure.
+void markFromRoots();
+// Process all unprocessed SATB buffers. It is called at the
+// beginning of an evacuation pause.
+void drainAllSATBBuffers();
+void checkpointRootsFinal(bool clear_all_soft_refs);
+void checkpointRootsFinalWork();
+void calcDesiredRegions();
+void cleanup();
+void completeCleanup();
+// Mark in the previous bitmap.  NB: this is usually read-only, so use
+// this carefully!
+void markPrev(oop p);
+void clear(oop p);
+// Clears marks for all objects in the given range, for both prev and
+// next bitmaps.  NB: the previous bitmap is usually read-only, so use
+// this carefully!
+void clearRangeBothMaps(MemRegion mr);
+// Record the current top of the mark and region stacks; a
+// subsequent oops_do() on the mark stack and
+// invalidate_entries_into_cset() on the region stack will iterate
+// only over indices valid at the time of this call.
+void set_oops_do_bound() {
+_markStack.set_oops_do_bound();
+_regionStack.set_oops_do_bound();
+}
+// Iterate over the oops in the mark stack and all local queues. It
+// also calls invalidate_entries_into_cset() on the region stack.
+void oops_do(OopClosure* f);
+// It is called at the end of an evacuation pause during marking so
+// that CM is notified of where the new end of the heap is. It
+// doesn't do anything if concurrent_marking_in_progress() is false,
+// unless the force parameter is true.
+void update_g1_committed(bool force = false);
+void complete_marking_in_collection_set();
+// It indicates that a new collection set is being chosen.
+void newCSet();
+// It registers a collection set heap region with CM. This is used
+// to determine whether any heap regions are located above the finger.
+void registerCSetRegion(HeapRegion* hr);
+// Returns "true" if at least one mark has been completed.
+bool at_least_one_mark_complete() { return _at_least_one_mark_complete; }
+bool isMarked(oop p) const {
+assert(p != NULL && p->is_oop(), "expected an oop");
+HeapWord* addr = (HeapWord*)p;
+assert(addr >= _nextMarkBitMap->startWord() ||
+addr < _nextMarkBitMap->endWord(), "in a region");
+return _nextMarkBitMap->isMarked(addr);
+}
+inline bool not_yet_marked(oop p) const;
+// XXX Debug code
+bool containing_card_is_marked(void* p);
+bool containing_cards_are_marked(void* start, void* last);
+bool isPrevMarked(oop p) const {
+assert(p != NULL && p->is_oop(), "expected an oop");
+HeapWord* addr = (HeapWord*)p;
+assert(addr >= _prevMarkBitMap->startWord() ||
+addr < _prevMarkBitMap->endWord(), "in a region");
+return _prevMarkBitMap->isMarked(addr);
+}
+inline bool do_yield_check(int worker_i = 0);
+inline bool should_yield();
+// Called to abort the marking cycle after a Full GC takes palce.
+void abort();
+void disable_co_trackers();
+// This prints the global/local fingers. It is used for debugging.
+NOT_PRODUCT(void print_finger();)
+void print_summary_info();
+// The following indicate whether a given verbose level has been
+// set. Notice that anything above stats is conditional to
+// _MARKING_VERBOSE_ having been set to 1
+bool verbose_stats()
+{ return _verbose_level >= stats_verbose; }
+bool verbose_low()
+{ return _MARKING_VERBOSE_ && _verbose_level >= low_verbose; }
+bool verbose_medium()
+{ return _MARKING_VERBOSE_ && _verbose_level >= medium_verbose; }
+bool verbose_high()
+{ return _MARKING_VERBOSE_ && _verbose_level >= high_verbose; }
+};
+// A class representing a marking task.
+class CMTask : public TerminatorTerminator {
+private:
+enum PrivateConstants {
+// the regular clock call is called once the scanned words reaches
+// this limit
+words_scanned_period          = 12*1024,
+// the regular clock call is called once the number of visited
+// references reaches this limit
+refs_reached_period           = 384,
+// initial value for the hash seed, used in the work stealing code
+init_hash_seed                = 17,
+// how many entries will be transferred between global stack and
+// local queues
+global_stack_transfer_size    = 16
+};
+int                         _task_id;
+G1CollectedHeap*            _g1h;
+ConcurrentMark*             _cm;
+CMBitMap*                   _nextMarkBitMap;
+// the task queue of this task
+CMTaskQueue*                _task_queue;
+// the task queue set---needed for stealing
+CMTaskQueueSet*             _task_queues;
+// indicates whether the task has been claimed---this is only  for
+// debugging purposes
+bool                        _claimed;
+// number of calls to this task
+int                         _calls;
+// concurrent overhead over a single CPU for this task
+COTracker                   _co_tracker;
+// when the virtual timer reaches this time, the marking step should
+// exit
+double                      _time_target_ms;
+// the start time of the current marking step
+double                      _start_time_ms;
+// the oop closure used for iterations over oops
+OopClosure*                 _oop_closure;
+// the region this task is scanning, NULL if we're not scanning any
+HeapRegion*                 _curr_region;
+// the local finger of this task, NULL if we're not scanning a region
+HeapWord*                   _finger;
+// limit of the region this task is scanning, NULL if we're not scanning one
+HeapWord*                   _region_limit;
+// This is used only when we scan regions popped from the region
+// stack. It records what the last object on such a region we
+// scanned was. It is used to ensure that, if we abort region
+// iteration, we do not rescan the first part of the region. This
+// should be NULL when we're not scanning a region from the region
+// stack.
+HeapWord*                   _region_finger;
+// the number of words this task has scanned
+size_t                      _words_scanned;
+// When _words_scanned reaches this limit, the regular clock is
+// called. Notice that this might be decreased under certain
+// circumstances (i.e. when we believe that we did an expensive
+// operation).
+size_t                      _words_scanned_limit;
+// the initial value of _words_scanned_limit (i.e. what it was
+// before it was decreased).
+size_t                      _real_words_scanned_limit;
+// the number of references this task has visited
+size_t                      _refs_reached;
+// When _refs_reached reaches this limit, the regular clock is
+// called. Notice this this might be decreased under certain
+// circumstances (i.e. when we believe that we did an expensive
+// operation).
+size_t                      _refs_reached_limit;
+// the initial value of _refs_reached_limit (i.e. what it was before
+// it was decreased).
+size_t                      _real_refs_reached_limit;
+// used by the work stealing stuff
+int                         _hash_seed;
+// if this is true, then the task has aborted for some reason
+bool                        _has_aborted;
+// set when the task aborts because it has met its time quota
+bool                        _has_aborted_timed_out;
+// true when we're draining SATB buffers; this avoids the task
+// aborting due to SATB buffers being available (as we're already
+// dealing with them)
+bool                        _draining_satb_buffers;
+// number sequence of past step times
+NumberSeq                   _step_times_ms;
+// elapsed time of this task
+double                      _elapsed_time_ms;
+// termination time of this task
+double                      _termination_time_ms;
+// when this task got into the termination protocol
+double                      _termination_start_time_ms;
+// true when the task is during a concurrent phase, false when it is
+// in the remark phase (so, in the latter case, we do not have to
+// check all the things that we have to check during the concurrent
+// phase, i.e. SATB buffer availability...)
+bool                        _concurrent;
+TruncatedSeq                _marking_step_diffs_ms;
+// LOTS of statistics related with this task
+#if _MARKING_STATS_
+NumberSeq                   _all_clock_intervals_ms;
+double                      _interval_start_time_ms;
+int                         _aborted;
+int                         _aborted_overflow;
+int                         _aborted_cm_aborted;
+int                         _aborted_yield;
+int                         _aborted_timed_out;
+int                         _aborted_satb;
+int                         _aborted_termination;
+int                         _steal_attempts;
+int                         _steals;
+int                         _clock_due_to_marking;
+int                         _clock_due_to_scanning;
+int                         _local_pushes;
+int                         _local_pops;
+int                         _local_max_size;
+int                         _objs_scanned;
+int                         _global_pushes;
+int                         _global_pops;
+int                         _global_max_size;
+int                         _global_transfers_to;
+int                         _global_transfers_from;
+int                         _region_stack_pops;
+int                         _regions_claimed;
+int                         _objs_found_on_bitmap;
+int                         _satb_buffers_processed;
+#endif // _MARKING_STATS_
+// it updates the local fields after this task has claimed
+// a new region to scan
+void setup_for_region(HeapRegion* hr);
+// it brings up-to-date the limit of the region
+void update_region_limit();
+// it resets the local fields after a task has finished scanning a
+// region
+void giveup_current_region();
+// called when either the words scanned or the refs visited limit
+// has been reached
+void reached_limit();
+// recalculates the words scanned and refs visited limits
+void recalculate_limits();
+// decreases the words scanned and refs visited limits when we reach
+// an expensive operation
+void decrease_limits();
+// it checks whether the words scanned or refs visited reached their
+// respective limit and calls reached_limit() if they have
+void check_limits() {
+if (_words_scanned >= _words_scanned_limit ||
+_refs_reached >= _refs_reached_limit)
+reached_limit();
+}
+// this is supposed to be called regularly during a marking step as
+// it checks a bunch of conditions that might cause the marking step
+// to abort
+void regular_clock_call();
+bool concurrent() { return _concurrent; }
+public:
+// It resets the task; it should be called right at the beginning of
+// a marking phase.
+void reset(CMBitMap* _nextMarkBitMap);
+// it clears all the fields that correspond to a claimed region.
+void clear_region_fields();
+void set_concurrent(bool concurrent) { _concurrent = concurrent; }
+void enable_co_tracker() {
+guarantee( !_co_tracker.enabled(), "invariant" );
+_co_tracker.enable();
+}
+void disable_co_tracker() {
+guarantee( _co_tracker.enabled(), "invariant" );
+_co_tracker.disable();
+}
+bool co_tracker_enabled() {
+return _co_tracker.enabled();
+}
+void reset_co_tracker(double starting_conc_overhead = 0.0) {
+_co_tracker.reset(starting_conc_overhead);
+}
+void start_co_tracker() {
+_co_tracker.start();
+}
+void update_co_tracker(bool force_end = false) {
+_co_tracker.update(force_end);
+}
+// The main method of this class which performs a marking step
+// trying not to exceed the given duration. However, it might exit
+// prematurely, according to some conditions (i.e. SATB buffers are
+// available for processing).
+void do_marking_step(double target_ms);
+// These two calls start and stop the timer
+void record_start_time() {
+_elapsed_time_ms = os::elapsedTime() * 1000.0;
+}
+void record_end_time() {
+_elapsed_time_ms = os::elapsedTime() * 1000.0 - _elapsed_time_ms;
+}
+// returns the task ID
+int task_id() { return _task_id; }
+// From TerminatorTerminator. It determines whether this task should
+// exit the termination protocol after it's entered it.
+virtual bool should_exit_termination();
+HeapWord* finger()            { return _finger; }
+bool has_aborted()            { return _has_aborted; }
+void set_has_aborted()        { _has_aborted = true; }
+void clear_has_aborted()      { _has_aborted = false; }
+bool claimed() { return _claimed; }
+void set_oop_closure(OopClosure* oop_closure) {
+_oop_closure = oop_closure;
+}
+// It grays the object by marking it and, if necessary, pushing it
+// on the local queue
+void deal_with_reference(oop obj);
+// It scans an object and visits its children.
+void scan_object(oop obj) {
+tmp_guarantee_CM( _nextMarkBitMap->isMarked((HeapWord*) obj),
+"invariant" );
+if (_cm->verbose_high())
+gclog_or_tty->print_cr("[%d] we're scanning object "PTR_FORMAT,
+_task_id, (void*) obj);
+size_t obj_size = obj->size();
+_words_scanned += obj_size;
+obj->oop_iterate(_oop_closure);
+statsOnly( ++_objs_scanned );
+check_limits();
+}
+// It pushes an object on the local queue.
+void push(oop obj);
+// These two move entries to/from the global stack.
+void move_entries_to_global_stack();
+void get_entries_from_global_stack();
+// It pops and scans objects from the local queue. If partially is
+// true, then it stops when the queue size is of a given limit. If
+// partially is false, then it stops when the queue is empty.
+void drain_local_queue(bool partially);
+// It moves entries from the global stack to the local queue and
+// drains the local queue. If partially is true, then it stops when
+// both the global stack and the local queue reach a given size. If
+// partially if false, it tries to empty them totally.
+void drain_global_stack(bool partially);
+// It keeps picking SATB buffers and processing them until no SATB
+// buffers are available.
+void drain_satb_buffers();
+// It keeps popping regions from the region stack and processing
+// them until the region stack is empty.
+void drain_region_stack(BitMapClosure* closure);
+// moves the local finger to a new location
+inline void move_finger_to(HeapWord* new_finger) {
+tmp_guarantee_CM( new_finger >= _finger && new_finger < _region_limit,
+"invariant" );
+_finger = new_finger;
+}
+// moves the region finger to a new location
+inline void move_region_finger_to(HeapWord* new_finger) {
+tmp_guarantee_CM( new_finger < _cm->finger(), "invariant" );
+_region_finger = new_finger;
+}
+CMTask(int task_num, ConcurrentMark *cm,
+CMTaskQueue* task_queue, CMTaskQueueSet* task_queues);
+// it prints statistics associated with this task
+void print_stats();
+#if _MARKING_STATS_
+void increase_objs_found_on_bitmap() { ++_objs_found_on_bitmap; }
+#endif // _MARKING_STATS_
+};

Mercurial > hg > truffle

comparison src/share/vm/gc_implementation/g1/concurrentMark.hpp @ 362:f8199438385b