| /* |
| * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
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| * |
| */ |
| |
| #ifndef SHARE_VM_GC_G1_G1CONCURRENTMARK_HPP |
| #define SHARE_VM_GC_G1_G1CONCURRENTMARK_HPP |
| |
| #include "classfile/javaClasses.hpp" |
| #include "gc/g1/g1RegionToSpaceMapper.hpp" |
| #include "gc/g1/heapRegionSet.hpp" |
| #include "gc/shared/taskqueue.hpp" |
| |
| class G1CollectedHeap; |
| class G1CMBitMap; |
| class G1CMTask; |
| class G1ConcurrentMark; |
| class ConcurrentGCTimer; |
| class G1OldTracer; |
| class G1SurvivorRegions; |
| typedef GenericTaskQueue<oop, mtGC> G1CMTaskQueue; |
| typedef GenericTaskQueueSet<G1CMTaskQueue, mtGC> G1CMTaskQueueSet; |
| |
| // Closure used by CM during concurrent reference discovery |
| // and reference processing (during remarking) to determine |
| // if a particular object is alive. It is primarily used |
| // to determine if referents of discovered reference objects |
| // are alive. An instance is also embedded into the |
| // reference processor as the _is_alive_non_header field |
| class G1CMIsAliveClosure: public BoolObjectClosure { |
| G1CollectedHeap* _g1; |
| public: |
| G1CMIsAliveClosure(G1CollectedHeap* g1) : _g1(g1) { } |
| |
| bool do_object_b(oop obj); |
| }; |
| |
| // A generic CM bit map. This is essentially a wrapper around the BitMap |
| // class, with one bit per (1<<_shifter) HeapWords. |
| |
| class G1CMBitMapRO VALUE_OBJ_CLASS_SPEC { |
| 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 |
| BitMapView _bm; // the bit map itself |
| |
| public: |
| // constructor |
| G1CMBitMapRO(int shifter); |
| |
| // inquiries |
| HeapWord* startWord() const { return _bmStartWord; } |
| // 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 |
| inline 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(const HeapWord* addr, |
| const HeapWord* limit = NULL) const; |
| |
| // conversion utilities |
| HeapWord* offsetToHeapWord(size_t offset) const { |
| return _bmStartWord + (offset << _shifter); |
| } |
| size_t heapWordToOffset(const HeapWord* addr) const { |
| return pointer_delta(addr, _bmStartWord) >> _shifter; |
| } |
| |
| // The argument addr should be the start address of a valid object |
| inline HeapWord* nextObject(HeapWord* addr); |
| |
| void print_on_error(outputStream* st, const char* prefix) const; |
| |
| // debugging |
| NOT_PRODUCT(bool covers(MemRegion rs) const;) |
| }; |
| |
| class G1CMBitMapMappingChangedListener : public G1MappingChangedListener { |
| private: |
| G1CMBitMap* _bm; |
| public: |
| G1CMBitMapMappingChangedListener() : _bm(NULL) {} |
| |
| void set_bitmap(G1CMBitMap* bm) { _bm = bm; } |
| |
| virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); |
| }; |
| |
| class G1CMBitMap : public G1CMBitMapRO { |
| private: |
| G1CMBitMapMappingChangedListener _listener; |
| |
| public: |
| static size_t compute_size(size_t heap_size); |
| // Returns the amount of bytes on the heap between two marks in the bitmap. |
| static size_t mark_distance(); |
| // Returns how many bytes (or bits) of the heap a single byte (or bit) of the |
| // mark bitmap corresponds to. This is the same as the mark distance above. |
| static size_t heap_map_factor() { |
| return mark_distance(); |
| } |
| |
| G1CMBitMap() : G1CMBitMapRO(LogMinObjAlignment), _listener() { _listener.set_bitmap(this); } |
| |
| // Initializes the underlying BitMap to cover the given area. |
| void initialize(MemRegion heap, G1RegionToSpaceMapper* storage); |
| |
| // Write marks. |
| inline void mark(HeapWord* addr); |
| inline void clear(HeapWord* addr); |
| inline bool parMark(HeapWord* addr); |
| |
| void clear_range(MemRegion mr); |
| }; |
| |
| // Represents a marking stack used by ConcurrentMarking in the G1 collector. |
| class G1CMMarkStack VALUE_OBJ_CLASS_SPEC { |
| VirtualSpace _virtual_space; // Underlying backing store for actual stack |
| G1ConcurrentMark* _cm; |
| oop* _base; // bottom of stack |
| jint _index; // one more than last occupied index |
| jint _capacity; // max #elements |
| jint _saved_index; // value of _index saved at start of GC |
| |
| bool _overflow; |
| bool _should_expand; |
| |
| public: |
| G1CMMarkStack(G1ConcurrentMark* cm); |
| ~G1CMMarkStack(); |
| |
| bool allocate(size_t capacity); |
| |
| // 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); |
| |
| bool isEmpty() { return _index == 0; } |
| int maxElems() { return _capacity; } |
| |
| bool overflow() { return _overflow; } |
| void clear_overflow() { _overflow = false; } |
| |
| bool should_expand() const { return _should_expand; } |
| void set_should_expand(); |
| |
| // Expand the stack, typically in response to an overflow condition |
| void expand(); |
| |
| int size() { return _index; } |
| |
| void setEmpty() { _index = 0; clear_overflow(); } |
| |
| // Record the current index. |
| void note_start_of_gc(); |
| |
| // Make sure that we have not added any entries to the stack during GC. |
| void note_end_of_gc(); |
| |
| // Apply fn to each oop in the mark stack, up to the bound recorded |
| // via one of the above "note" functions. The mark stack must not |
| // be modified while iterating. |
| template<typename Fn> void iterate(Fn fn); |
| }; |
| |
| // Root Regions are regions that are not empty at the beginning of a |
| // marking cycle and which we might collect during an evacuation pause |
| // while the cycle is active. Given that, during evacuation pauses, we |
| // do not copy objects that are explicitly marked, what we have to do |
| // for the root regions is to scan them and mark all objects reachable |
| // from them. According to the SATB assumptions, we only need to visit |
| // each object once during marking. So, as long as we finish this scan |
| // before the next evacuation pause, we can copy the objects from the |
| // root regions without having to mark them or do anything else to them. |
| // |
| // Currently, we only support root region scanning once (at the start |
| // of the marking cycle) and the root regions are all the survivor |
| // regions populated during the initial-mark pause. |
| class G1CMRootRegions VALUE_OBJ_CLASS_SPEC { |
| private: |
| const G1SurvivorRegions* _survivors; |
| G1ConcurrentMark* _cm; |
| |
| volatile bool _scan_in_progress; |
| volatile bool _should_abort; |
| volatile int _claimed_survivor_index; |
| |
| void notify_scan_done(); |
| |
| public: |
| G1CMRootRegions(); |
| // We actually do most of the initialization in this method. |
| void init(const G1SurvivorRegions* survivors, G1ConcurrentMark* cm); |
| |
| // Reset the claiming / scanning of the root regions. |
| void prepare_for_scan(); |
| |
| // Forces get_next() to return NULL so that the iteration aborts early. |
| void abort() { _should_abort = true; } |
| |
| // Return true if the CM thread are actively scanning root regions, |
| // false otherwise. |
| bool scan_in_progress() { return _scan_in_progress; } |
| |
| // Claim the next root region to scan atomically, or return NULL if |
| // all have been claimed. |
| HeapRegion* claim_next(); |
| |
| // The number of root regions to scan. |
| uint num_root_regions() const; |
| |
| void cancel_scan(); |
| |
| // Flag that we're done with root region scanning and notify anyone |
| // who's waiting on it. If aborted is false, assume that all regions |
| // have been claimed. |
| void scan_finished(); |
| |
| // If CM threads are still scanning root regions, wait until they |
| // are done. Return true if we had to wait, false otherwise. |
| bool wait_until_scan_finished(); |
| }; |
| |
| class ConcurrentMarkThread; |
| |
| class G1ConcurrentMark: public CHeapObj<mtGC> { |
| friend class ConcurrentMarkThread; |
| friend class G1ParNoteEndTask; |
| friend class G1VerifyLiveDataClosure; |
| friend class G1CMRefProcTaskProxy; |
| friend class G1CMRefProcTaskExecutor; |
| friend class G1CMKeepAliveAndDrainClosure; |
| friend class G1CMDrainMarkingStackClosure; |
| friend class G1CMBitMapClosure; |
| friend class G1CMConcurrentMarkingTask; |
| friend class G1CMMarkStack; |
| friend class G1CMRemarkTask; |
| friend class G1CMTask; |
| |
| protected: |
| ConcurrentMarkThread* _cmThread; // The thread doing the work |
| G1CollectedHeap* _g1h; // The heap |
| uint _parallel_marking_threads; // The number of marking |
| // threads we're using |
| uint _max_parallel_marking_threads; // Max number of marking |
| // threads we'll ever 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 |
| |
| FreeRegionList _cleanup_list; |
| |
| // Concurrent marking support structures |
| G1CMBitMap _markBitMap1; |
| G1CMBitMap _markBitMap2; |
| G1CMBitMapRO* _prevMarkBitMap; // Completed mark bitmap |
| G1CMBitMap* _nextMarkBitMap; // Under-construction mark bitmap |
| |
| // Heap bounds |
| HeapWord* _heap_start; |
| HeapWord* _heap_end; |
| |
| // Root region tracking and claiming |
| G1CMRootRegions _root_regions; |
| |
| // For gray objects |
| G1CMMarkStack _markStack; // Grey objects behind global finger |
| HeapWord* volatile _finger; // The global finger, region aligned, |
| // always points to the end of the |
| // last claimed region |
| |
| // Marking tasks |
| uint _max_worker_id;// Maximum worker id |
| uint _active_tasks; // Task num currently active |
| G1CMTask** _tasks; // Task queue array (max_worker_id len) |
| G1CMTaskQueueSet* _task_queues; // Task queue set |
| ParallelTaskTerminator _terminator; // For termination |
| |
| // Two sync barriers that are used to synchronize 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-initialize |
| // their data structures and task 0 re-initializes 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-initialized. 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; |
| |
| ConcurrentGCTimer* _gc_timer_cm; |
| |
| G1OldTracer* _gc_tracer_cm; |
| |
| // 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 weakRefsWorkParallelPart(BoolObjectClosure* is_alive, bool purged_classes); |
| 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(); |
| |
| // Resets all the marking data structures. Called when we have to restart |
| // marking or when marking completes (via set_non_marking_state below). |
| void reset_marking_state(bool clear_overflow = true); |
| |
| // We do this after we're done with marking so that the marking data |
| // structures are initialized to a sensible and predictable state. |
| void set_non_marking_state(); |
| |
| // Called to indicate how many threads are currently active. |
| void set_concurrency(uint active_tasks); |
| |
| // It should be called to indicate which phase we're in (concurrent |
| // mark or remark) and how many threads are currently active. |
| void set_concurrency_and_phase(uint active_tasks, bool concurrent); |
| |
| // Prints all gathered CM-related statistics |
| void print_stats(); |
| |
| bool cleanup_list_is_empty() { |
| return _cleanup_list.is_empty(); |
| } |
| |
| // Accessor methods |
| uint parallel_marking_threads() const { return _parallel_marking_threads; } |
| uint max_parallel_marking_threads() const { return _max_parallel_marking_threads;} |
| double sleep_factor() { return _sleep_factor; } |
| double marking_task_overhead() { return _marking_task_overhead;} |
| |
| HeapWord* finger() { return _finger; } |
| bool concurrent() { return _concurrent; } |
| uint active_tasks() { return _active_tasks; } |
| ParallelTaskTerminator* terminator() { return &_terminator; } |
| |
| // It claims the next available region to be scanned by a marking |
| // task/thread. 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(uint worker_id); |
| |
| // It determines whether we've run out of regions to scan. Note that |
| // the finger can point past the heap end in case the heap was expanded |
| // to satisfy an allocation without doing a GC. This is fine, because all |
| // objects in those regions will be considered live anyway because of |
| // SATB guarantees (i.e. their TAMS will be equal to bottom). |
| bool out_of_regions() { return _finger >= _heap_end; } |
| |
| // Returns the task with the given id |
| G1CMTask* task(int id) { |
| assert(0 <= id && id < (int) _active_tasks, |
| "task id not within active bounds"); |
| return _tasks[id]; |
| } |
| |
| // Returns the task queue with the given id |
| G1CMTaskQueue* task_queue(int id) { |
| assert(0 <= id && id < (int) _active_tasks, |
| "task queue id not within active bounds"); |
| return (G1CMTaskQueue*) _task_queues->queue(id); |
| } |
| |
| // Returns the task queue set |
| G1CMTaskQueueSet* task_queues() { return _task_queues; } |
| |
| // Access / manipulation of the overflow flag which is set to |
| // indicate that the global stack has overflown |
| bool has_overflown() { return _has_overflown; } |
| void set_has_overflown() { _has_overflown = true; } |
| void clear_has_overflown() { _has_overflown = false; } |
| bool restart_for_overflow() { return _restart_for_overflow; } |
| |
| // Methods to enter the two overflow sync barriers |
| void enter_first_sync_barrier(uint worker_id); |
| void enter_second_sync_barrier(uint worker_id); |
| |
| // Card index of the bottom of the G1 heap. Used for biasing indices into |
| // the card bitmaps. |
| intptr_t _heap_bottom_card_num; |
| |
| // Set to true when initialization is complete |
| bool _completed_initialization; |
| |
| // end_timer, true to end gc timer after ending concurrent phase. |
| void register_concurrent_phase_end_common(bool end_timer); |
| |
| // Clear the given bitmap in parallel using the given WorkGang. If may_yield is |
| // true, periodically insert checks to see if this method should exit prematurely. |
| void clear_bitmap(G1CMBitMap* bitmap, WorkGang* workers, bool may_yield); |
| public: |
| // Manipulation of the global mark stack. |
| // The push and pop operations are used by tasks for transfers |
| // between task-local queues and the global mark stack, and use |
| // locking for concurrency safety. |
| 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(); } |
| |
| G1CMRootRegions* root_regions() { return &_root_regions; } |
| |
| 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 concurrent_cycle_start(); |
| void concurrent_cycle_end(); |
| |
| void update_accum_task_vtime(int i, double vtime) { |
| _accum_task_vtime[i] += vtime; |
| } |
| |
| double all_task_accum_vtime() { |
| double ret = 0.0; |
| for (uint i = 0; i < _max_worker_id; ++i) |
| ret += _accum_task_vtime[i]; |
| return ret; |
| } |
| |
| // Attempts to steal an object from the task queues of other tasks |
| bool try_stealing(uint worker_id, int* hash_seed, oop& obj); |
| |
| G1ConcurrentMark(G1CollectedHeap* g1h, |
| G1RegionToSpaceMapper* prev_bitmap_storage, |
| G1RegionToSpaceMapper* next_bitmap_storage); |
| ~G1ConcurrentMark(); |
| |
| ConcurrentMarkThread* cmThread() { return _cmThread; } |
| |
| G1CMBitMapRO* prevMarkBitMap() const { return _prevMarkBitMap; } |
| G1CMBitMap* nextMarkBitMap() const { return _nextMarkBitMap; } |
| |
| // Returns the number of GC threads to be used in a concurrent |
| // phase based on the number of GC threads being used in a STW |
| // phase. |
| uint scale_parallel_threads(uint n_par_threads); |
| |
| // Calculates the number of GC threads to be used in a concurrent phase. |
| uint calc_parallel_marking_threads(); |
| |
| // The following three are interaction between CM and |
| // G1CollectedHeap |
| |
| // This notifies CM that a root during initial-mark needs to be |
| // grayed. It is MT-safe. hr is the region that |
| // contains the object and it's passed optionally from callers who |
| // might already have it (no point in recalculating it). |
| inline void grayRoot(oop obj, |
| HeapRegion* hr = NULL); |
| |
| // Prepare internal data structures for the next mark cycle. This includes clearing |
| // the next mark bitmap and some internal data structures. This method is intended |
| // to be called concurrently to the mutator. It will yield to safepoint requests. |
| void cleanup_for_next_mark(); |
| |
| // Clear the previous marking bitmap during safepoint. |
| void clear_prev_bitmap(WorkGang* workers); |
| |
| // Return whether the next mark bitmap has no marks set. To be used for assertions |
| // only. Will not yield to pause requests. |
| bool nextMarkBitmapIsClear(); |
| |
| // 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(); |
| |
| // Scan all the root regions and mark everything reachable from |
| // them. |
| void scan_root_regions(); |
| |
| // Scan a single root region and mark everything reachable from it. |
| void scanRootRegion(HeapRegion* hr); |
| |
| // Do concurrent phase of marking, to a tentative transitive closure. |
| void mark_from_roots(); |
| |
| void checkpointRootsFinal(bool clear_all_soft_refs); |
| void checkpointRootsFinalWork(); |
| void cleanup(); |
| void complete_cleanup(); |
| |
| // Mark in the previous bitmap. NB: this is usually read-only, so use |
| // this carefully! |
| inline void markPrev(oop p); |
| |
| // Clears marks for all objects in the given range, for the prev or |
| // next bitmaps. NB: the previous bitmap is usually |
| // read-only, so use this carefully! |
| void clearRangePrevBitmap(MemRegion mr); |
| |
| // Notify data structures that a GC has started. |
| void note_start_of_gc() { |
| _markStack.note_start_of_gc(); |
| } |
| |
| // Notify data structures that a GC is finished. |
| void note_end_of_gc() { |
| _markStack.note_end_of_gc(); |
| } |
| |
| // Verify that there are no CSet oops on the stacks (taskqueues / |
| // global mark stack) and fingers (global / per-task). |
| // If marking is not in progress, it's a no-op. |
| void verify_no_cset_oops() PRODUCT_RETURN; |
| |
| inline bool isPrevMarked(oop p) const; |
| |
| inline bool do_yield_check(); |
| |
| // Abandon current marking iteration due to a Full GC. |
| void abort(); |
| |
| bool has_aborted() { return _has_aborted; } |
| |
| void print_summary_info(); |
| |
| void print_worker_threads_on(outputStream* st) const; |
| void threads_do(ThreadClosure* tc) const; |
| |
| void print_on_error(outputStream* st) const; |
| |
| // Attempts to mark the given object on the next mark bitmap. |
| inline bool par_mark(oop obj); |
| |
| // Returns true if initialization was successfully completed. |
| bool completed_initialization() const { |
| return _completed_initialization; |
| } |
| |
| ConcurrentGCTimer* gc_timer_cm() const { return _gc_timer_cm; } |
| G1OldTracer* gc_tracer_cm() const { return _gc_tracer_cm; } |
| |
| private: |
| // Clear (Reset) all liveness count data. |
| void clear_live_data(WorkGang* workers); |
| |
| #ifdef ASSERT |
| // Verify all of the above data structures that they are in initial state. |
| void verify_live_data_clear(); |
| #endif |
| |
| // Aggregates the per-card liveness data based on the current marking. Also sets |
| // the amount of marked bytes for each region. |
| void create_live_data(); |
| |
| void finalize_live_data(); |
| |
| void verify_live_data(); |
| }; |
| |
| // A class representing a marking task. |
| class G1CMTask : 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 |
| }; |
| |
| uint _worker_id; |
| G1CollectedHeap* _g1h; |
| G1ConcurrentMark* _cm; |
| G1CMBitMap* _nextMarkBitMap; |
| // the task queue of this task |
| G1CMTaskQueue* _task_queue; |
| private: |
| // the task queue set---needed for stealing |
| G1CMTaskQueueSet* _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; |
| |
| // 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 |
| G1CMOopClosure* _cm_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; |
| |
| // 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_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; |
| |
| // 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(); |
| |
| // 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; } |
| |
| // Test whether obj might have already been passed over by the |
| // mark bitmap scan, and so needs to be pushed onto the mark stack. |
| bool is_below_finger(oop obj, HeapWord* global_finger) const; |
| |
| template<bool scan> void process_grey_object(oop obj); |
| |
| public: |
| // It resets the task; it should be called right at the beginning of |
| // a marking phase. |
| void reset(G1CMBitMap* _nextMarkBitMap); |
| // it clears all the fields that correspond to a claimed region. |
| void clear_region_fields(); |
| |
| void set_concurrent(bool concurrent) { _concurrent = concurrent; } |
| |
| // 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, |
| bool do_termination, |
| bool is_serial); |
| |
| // 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 worker ID associated with this task. |
| uint worker_id() { return _worker_id; } |
| |
| // From TerminatorTerminator. It determines whether this task should |
| // exit the termination protocol after it's entered it. |
| virtual bool should_exit_termination(); |
| |
| // Resets the local region fields after a task has finished scanning a |
| // region; or when they have become stale as a result of the region |
| // being evacuated. |
| void giveup_current_region(); |
| |
| 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 has_timed_out() { return _has_timed_out; } |
| bool claimed() { return _claimed; } |
| |
| void set_cm_oop_closure(G1CMOopClosure* cm_oop_closure); |
| |
| // Increment the number of references this task has visited. |
| void increment_refs_reached() { ++_refs_reached; } |
| |
| // Grey the object by marking it. If not already marked, push it on |
| // the local queue if below the finger. |
| // obj is below its region's NTAMS. |
| inline void make_reference_grey(oop obj); |
| |
| // Grey the object (by calling make_grey_reference) if required, |
| // e.g. obj is below its containing region's NTAMS. |
| // Precondition: obj is a valid heap object. |
| inline void deal_with_reference(oop obj); |
| |
| // It scans an object and visits its children. |
| inline void scan_object(oop obj); |
| |
| // It pushes an object on the local queue. |
| inline 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(); |
| |
| // moves the local finger to a new location |
| inline void move_finger_to(HeapWord* new_finger) { |
| assert(new_finger >= _finger && new_finger < _region_limit, "invariant"); |
| _finger = new_finger; |
| } |
| |
| G1CMTask(uint worker_id, |
| G1ConcurrentMark *cm, |
| G1CMTaskQueue* task_queue, |
| G1CMTaskQueueSet* task_queues); |
| |
| // it prints statistics associated with this task |
| void print_stats(); |
| }; |
| |
| // Class that's used to to print out per-region liveness |
| // information. It's currently used at the end of marking and also |
| // after we sort the old regions at the end of the cleanup operation. |
| class G1PrintRegionLivenessInfoClosure: public HeapRegionClosure { |
| private: |
| // Accumulators for these values. |
| size_t _total_used_bytes; |
| size_t _total_capacity_bytes; |
| size_t _total_prev_live_bytes; |
| size_t _total_next_live_bytes; |
| |
| // Accumulator for the remembered set size |
| size_t _total_remset_bytes; |
| |
| // Accumulator for strong code roots memory size |
| size_t _total_strong_code_roots_bytes; |
| |
| static double perc(size_t val, size_t total) { |
| if (total == 0) { |
| return 0.0; |
| } else { |
| return 100.0 * ((double) val / (double) total); |
| } |
| } |
| |
| static double bytes_to_mb(size_t val) { |
| return (double) val / (double) M; |
| } |
| |
| public: |
| // The header and footer are printed in the constructor and |
| // destructor respectively. |
| G1PrintRegionLivenessInfoClosure(const char* phase_name); |
| virtual bool doHeapRegion(HeapRegion* r); |
| ~G1PrintRegionLivenessInfoClosure(); |
| }; |
| |
| #endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_HPP |