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/*
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* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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// ConcurrentMarkSweepGeneration is in support of a concurrent
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// mark-sweep old generation in the Detlefs-Printezis--Boehm-Demers-Schenker
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// style. We assume, for now, that this generation is always the
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// seniormost generation (modulo the PermGeneration), and for simplicity
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// in the first implementation, that this generation is a single compactible
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// space. Neither of these restrictions appears essential, and will be
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// relaxed in the future when more time is available to implement the
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// greater generality (and there's a need for it).
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//
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// Concurrent mode failures are currently handled by
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// means of a sliding mark-compact.
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class CMSAdaptiveSizePolicy;
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class CMSConcMarkingTask;
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class CMSGCAdaptivePolicyCounters;
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class ConcurrentMarkSweepGeneration;
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class ConcurrentMarkSweepPolicy;
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class ConcurrentMarkSweepThread;
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class CompactibleFreeListSpace;
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class FreeChunk;
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class PromotionInfo;
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class ScanMarkedObjectsAgainCarefullyClosure;
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// A generic CMS bit map. It's the basis for both the CMS marking bit map
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// as well as for the mod union table (in each case only a subset of the
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// methods are used). This is essentially a wrapper around the BitMap class,
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// with one bit per (1<<_shifter) HeapWords. (i.e. for the marking bit map,
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// we have _shifter == 0. and for the mod union table we have
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// shifter == CardTableModRefBS::card_shift - LogHeapWordSize.)
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// XXX 64-bit issues in BitMap?
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class CMSBitMap VALUE_OBJ_CLASS_SPEC {
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friend class VMStructs;
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HeapWord* _bmStartWord; // base address of range covered by map
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size_t _bmWordSize; // map size (in #HeapWords covered)
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const int _shifter; // shifts to convert HeapWord to bit position
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VirtualSpace _virtual_space; // underlying the bit map
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BitMap _bm; // the bit map itself
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public:
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Mutex* const _lock; // mutex protecting _bm;
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public:
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// constructor
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CMSBitMap(int shifter, int mutex_rank, const char* mutex_name);
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// allocates the actual storage for the map
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bool allocate(MemRegion mr);
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// field getter
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Mutex* lock() const { return _lock; }
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// locking verifier convenience function
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void assert_locked() const PRODUCT_RETURN;
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// inquiries
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HeapWord* startWord() const { return _bmStartWord; }
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size_t sizeInWords() const { return _bmWordSize; }
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size_t sizeInBits() const { return _bm.size(); }
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// the following is one past the last word in space
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HeapWord* endWord() const { return _bmStartWord + _bmWordSize; }
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// reading marks
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bool isMarked(HeapWord* addr) const;
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bool par_isMarked(HeapWord* addr) const; // do not lock checks
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bool isUnmarked(HeapWord* addr) const;
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bool isAllClear() const;
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// writing marks
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void mark(HeapWord* addr);
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// For marking by parallel GC threads;
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// returns true if we did, false if another thread did
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bool par_mark(HeapWord* addr);
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void mark_range(MemRegion mr);
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void par_mark_range(MemRegion mr);
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void mark_large_range(MemRegion mr);
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void par_mark_large_range(MemRegion mr);
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void par_clear(HeapWord* addr); // For unmarking by parallel GC threads.
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void clear_range(MemRegion mr);
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void par_clear_range(MemRegion mr);
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void clear_large_range(MemRegion mr);
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void par_clear_large_range(MemRegion mr);
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void clear_all();
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void clear_all_incrementally(); // Not yet implemented!!
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NOT_PRODUCT(
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// checks the memory region for validity
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void region_invariant(MemRegion mr);
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)
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// iteration
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void iterate(BitMapClosure* cl) {
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_bm.iterate(cl);
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}
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void iterate(BitMapClosure* cl, HeapWord* left, HeapWord* right);
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void dirty_range_iterate_clear(MemRegionClosure* cl);
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void dirty_range_iterate_clear(MemRegion mr, MemRegionClosure* cl);
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// auxiliary support for iteration
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HeapWord* getNextMarkedWordAddress(HeapWord* addr) const;
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HeapWord* getNextMarkedWordAddress(HeapWord* start_addr,
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HeapWord* end_addr) const;
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HeapWord* getNextUnmarkedWordAddress(HeapWord* addr) const;
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HeapWord* getNextUnmarkedWordAddress(HeapWord* start_addr,
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HeapWord* end_addr) const;
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MemRegion getAndClearMarkedRegion(HeapWord* addr);
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MemRegion getAndClearMarkedRegion(HeapWord* start_addr,
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HeapWord* end_addr);
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// conversion utilities
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HeapWord* offsetToHeapWord(size_t offset) const;
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size_t heapWordToOffset(HeapWord* addr) const;
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size_t heapWordDiffToOffsetDiff(size_t diff) const;
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// debugging
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// is this address range covered by the bit-map?
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NOT_PRODUCT(
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bool covers(MemRegion mr) const;
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bool covers(HeapWord* start, size_t size = 0) const;
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)
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void verifyNoOneBitsInRange(HeapWord* left, HeapWord* right) PRODUCT_RETURN;
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};
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// Represents a marking stack used by the CMS collector.
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// Ideally this should be GrowableArray<> just like MSC's marking stack(s).
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class CMSMarkStack: public CHeapObj {
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//
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friend class CMSCollector; // to get at expasion stats further below
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//
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VirtualSpace _virtual_space; // space for the stack
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oop* _base; // bottom of stack
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size_t _index; // one more than last occupied index
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size_t _capacity; // max #elements
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Mutex _par_lock; // an advisory lock used in case of parallel access
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NOT_PRODUCT(size_t _max_depth;) // max depth plumbed during run
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protected:
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size_t _hit_limit; // we hit max stack size limit
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size_t _failed_double; // we failed expansion before hitting limit
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public:
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CMSMarkStack():
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_par_lock(Mutex::event, "CMSMarkStack._par_lock", true),
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_hit_limit(0),
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_failed_double(0) {}
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bool allocate(size_t size);
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size_t capacity() const { return _capacity; }
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oop pop() {
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if (!isEmpty()) {
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return _base[--_index] ;
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}
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return NULL;
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}
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bool push(oop ptr) {
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if (isFull()) {
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return false;
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} else {
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_base[_index++] = ptr;
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NOT_PRODUCT(_max_depth = MAX2(_max_depth, _index));
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return true;
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}
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}
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bool isEmpty() const { return _index == 0; }
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bool isFull() const {
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assert(_index <= _capacity, "buffer overflow");
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return _index == _capacity;
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}
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size_t length() { return _index; }
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// "Parallel versions" of some of the above
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oop par_pop() {
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// lock and pop
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MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag);
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return pop();
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}
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bool par_push(oop ptr) {
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// lock and push
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MutexLockerEx x(&_par_lock, Mutex::_no_safepoint_check_flag);
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return push(ptr);
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}
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// Forcibly reset the stack, losing all of its contents.
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void reset() {
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_index = 0;
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}
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// Expand the stack, typically in response to an overflow condition
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void expand();
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// Compute the least valued stack element.
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oop least_value(HeapWord* low) {
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oop least = (oop)low;
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for (size_t i = 0; i < _index; i++) {
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least = MIN2(least, _base[i]);
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}
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return least;
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}
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// Exposed here to allow stack expansion in || case
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Mutex* par_lock() { return &_par_lock; }
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};
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class CardTableRS;
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class CMSParGCThreadState;
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class ModUnionClosure: public MemRegionClosure {
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protected:
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CMSBitMap* _t;
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public:
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ModUnionClosure(CMSBitMap* t): _t(t) { }
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void do_MemRegion(MemRegion mr);
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};
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class ModUnionClosurePar: public ModUnionClosure {
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public:
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ModUnionClosurePar(CMSBitMap* t): ModUnionClosure(t) { }
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void do_MemRegion(MemRegion mr);
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};
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// Survivor Chunk Array in support of parallelization of
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// Survivor Space rescan.
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class ChunkArray: public CHeapObj {
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size_t _index;
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size_t _capacity;
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HeapWord** _array; // storage for array
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public:
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ChunkArray() : _index(0), _capacity(0), _array(NULL) {}
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ChunkArray(HeapWord** a, size_t c):
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_index(0), _capacity(c), _array(a) {}
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HeapWord** array() { return _array; }
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void set_array(HeapWord** a) { _array = a; }
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size_t capacity() { return _capacity; }
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void set_capacity(size_t c) { _capacity = c; }
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size_t end() {
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assert(_index < capacity(), "_index out of bounds");
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return _index;
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} // exclusive
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HeapWord* nth(size_t n) {
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assert(n < end(), "Out of bounds access");
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return _array[n];
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}
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void reset() {
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_index = 0;
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}
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void record_sample(HeapWord* p, size_t sz) {
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// For now we do not do anything with the size
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if (_index < _capacity) {
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_array[_index++] = p;
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}
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}
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};
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//
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// Timing, allocation and promotion statistics for gc scheduling and incremental
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// mode pacing. Most statistics are exponential averages.
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//
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class CMSStats VALUE_OBJ_CLASS_SPEC {
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private:
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ConcurrentMarkSweepGeneration* const _cms_gen; // The cms (old) gen.
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// The following are exponential averages with factor alpha:
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// avg = (100 - alpha) * avg + alpha * cur_sample
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//
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// The durations measure: end_time[n] - start_time[n]
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// The periods measure: start_time[n] - start_time[n-1]
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//
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// The cms period and duration include only concurrent collections; time spent
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// in foreground cms collections due to System.gc() or because of a failure to
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// keep up are not included.
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//
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// There are 3 alphas to "bootstrap" the statistics. The _saved_alpha is the
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// real value, but is used only after the first period. A value of 100 is
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// used for the first sample so it gets the entire weight.
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unsigned int _saved_alpha; // 0-100
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unsigned int _gc0_alpha;
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unsigned int _cms_alpha;
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double _gc0_duration;
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double _gc0_period;
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size_t _gc0_promoted; // bytes promoted per gc0
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double _cms_duration;
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double _cms_duration_pre_sweep; // time from initiation to start of sweep
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double _cms_duration_per_mb;
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double _cms_period;
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size_t _cms_allocated; // bytes of direct allocation per gc0 period
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// Timers.
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elapsedTimer _cms_timer;
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TimeStamp _gc0_begin_time;
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TimeStamp _cms_begin_time;
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TimeStamp _cms_end_time;
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// Snapshots of the amount used in the CMS generation.
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size_t _cms_used_at_gc0_begin;
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size_t _cms_used_at_gc0_end;
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size_t _cms_used_at_cms_begin;
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// Used to prevent the duty cycle from being reduced in the middle of a cms
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// cycle.
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bool _allow_duty_cycle_reduction;
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enum {
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_GC0_VALID = 0x1,
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_CMS_VALID = 0x2,
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_ALL_VALID = _GC0_VALID | _CMS_VALID
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};
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unsigned int _valid_bits;
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unsigned int _icms_duty_cycle; // icms duty cycle (0-100).
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protected:
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// Return a duty cycle that avoids wild oscillations, by limiting the amount
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// of change between old_duty_cycle and new_duty_cycle (the latter is treated
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// as a recommended value).
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static unsigned int icms_damped_duty_cycle(unsigned int old_duty_cycle,
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unsigned int new_duty_cycle);
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unsigned int icms_update_duty_cycle_impl();
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public:
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CMSStats(ConcurrentMarkSweepGeneration* cms_gen,
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unsigned int alpha = CMSExpAvgFactor);
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// Whether or not the statistics contain valid data; higher level statistics
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// cannot be called until this returns true (they require at least one young
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// gen and one cms cycle to have completed).
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bool valid() const;
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// Record statistics.
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void record_gc0_begin();
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void record_gc0_end(size_t cms_gen_bytes_used);
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void record_cms_begin();
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void record_cms_end();
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// Allow management of the cms timer, which must be stopped/started around
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// yield points.
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elapsedTimer& cms_timer() { return _cms_timer; }
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void start_cms_timer() { _cms_timer.start(); }
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void stop_cms_timer() { _cms_timer.stop(); }
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// Basic statistics; units are seconds or bytes.
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double gc0_period() const { return _gc0_period; }
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double gc0_duration() const { return _gc0_duration; }
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size_t gc0_promoted() const { return _gc0_promoted; }
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double cms_period() const { return _cms_period; }
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double cms_duration() const { return _cms_duration; }
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double cms_duration_per_mb() const { return _cms_duration_per_mb; }
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size_t cms_allocated() const { return _cms_allocated; }
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size_t cms_used_at_gc0_end() const { return _cms_used_at_gc0_end;}
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// Seconds since the last background cms cycle began or ended.
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double cms_time_since_begin() const;
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double cms_time_since_end() const;
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// Higher level statistics--caller must check that valid() returns true before
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// calling.
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// Returns bytes promoted per second of wall clock time.
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double promotion_rate() const;
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// Returns bytes directly allocated per second of wall clock time.
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double cms_allocation_rate() const;
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402 |
|
|
403 |
// Rate at which space in the cms generation is being consumed (sum of the
|
|
404 |
// above two).
|
|
405 |
double cms_consumption_rate() const;
|
|
406 |
|
|
407 |
// Returns an estimate of the number of seconds until the cms generation will
|
|
408 |
// fill up, assuming no collection work is done.
|
|
409 |
double time_until_cms_gen_full() const;
|
|
410 |
|
|
411 |
// Returns an estimate of the number of seconds remaining until
|
|
412 |
// the cms generation collection should start.
|
|
413 |
double time_until_cms_start() const;
|
|
414 |
|
|
415 |
// End of higher level statistics.
|
|
416 |
|
|
417 |
// Returns the cms incremental mode duty cycle, as a percentage (0-100).
|
|
418 |
unsigned int icms_duty_cycle() const { return _icms_duty_cycle; }
|
|
419 |
|
|
420 |
// Update the duty cycle and return the new value.
|
|
421 |
unsigned int icms_update_duty_cycle();
|
|
422 |
|
|
423 |
// Debugging.
|
|
424 |
void print_on(outputStream* st) const PRODUCT_RETURN;
|
|
425 |
void print() const { print_on(gclog_or_tty); }
|
|
426 |
};
|
|
427 |
|
|
428 |
// A closure related to weak references processing which
|
|
429 |
// we embed in the CMSCollector, since we need to pass
|
|
430 |
// it to the reference processor for secondary filtering
|
|
431 |
// of references based on reachability of referent;
|
|
432 |
// see role of _is_alive_non_header closure in the
|
|
433 |
// ReferenceProcessor class.
|
|
434 |
// For objects in the CMS generation, this closure checks
|
|
435 |
// if the object is "live" (reachable). Used in weak
|
|
436 |
// reference processing.
|
|
437 |
class CMSIsAliveClosure: public BoolObjectClosure {
|
|
438 |
MemRegion _span;
|
|
439 |
const CMSBitMap* _bit_map;
|
|
440 |
|
|
441 |
friend class CMSCollector;
|
|
442 |
protected:
|
|
443 |
void set_span(MemRegion span) { _span = span; }
|
|
444 |
public:
|
|
445 |
CMSIsAliveClosure(CMSBitMap* bit_map):
|
|
446 |
_bit_map(bit_map) { }
|
|
447 |
|
|
448 |
CMSIsAliveClosure(MemRegion span,
|
|
449 |
CMSBitMap* bit_map):
|
|
450 |
_span(span),
|
|
451 |
_bit_map(bit_map) { }
|
|
452 |
void do_object(oop obj) {
|
|
453 |
assert(false, "not to be invoked");
|
|
454 |
}
|
|
455 |
bool do_object_b(oop obj);
|
|
456 |
};
|
|
457 |
|
|
458 |
|
|
459 |
// Implements AbstractRefProcTaskExecutor for CMS.
|
|
460 |
class CMSRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
|
|
461 |
public:
|
|
462 |
|
|
463 |
CMSRefProcTaskExecutor(CMSCollector& collector)
|
|
464 |
: _collector(collector)
|
|
465 |
{ }
|
|
466 |
|
|
467 |
// Executes a task using worker threads.
|
|
468 |
virtual void execute(ProcessTask& task);
|
|
469 |
virtual void execute(EnqueueTask& task);
|
|
470 |
private:
|
|
471 |
CMSCollector& _collector;
|
|
472 |
};
|
|
473 |
|
|
474 |
|
|
475 |
class CMSCollector: public CHeapObj {
|
|
476 |
friend class VMStructs;
|
|
477 |
friend class ConcurrentMarkSweepThread;
|
|
478 |
friend class ConcurrentMarkSweepGeneration;
|
|
479 |
friend class CompactibleFreeListSpace;
|
|
480 |
friend class CMSParRemarkTask;
|
|
481 |
friend class CMSConcMarkingTask;
|
|
482 |
friend class CMSRefProcTaskProxy;
|
|
483 |
friend class CMSRefProcTaskExecutor;
|
|
484 |
friend class ScanMarkedObjectsAgainCarefullyClosure; // for sampling eden
|
|
485 |
friend class SurvivorSpacePrecleanClosure; // --- ditto -------
|
|
486 |
friend class PushOrMarkClosure; // to access _restart_addr
|
|
487 |
friend class Par_PushOrMarkClosure; // to access _restart_addr
|
|
488 |
friend class MarkFromRootsClosure; // -- ditto --
|
|
489 |
// ... and for clearing cards
|
|
490 |
friend class Par_MarkFromRootsClosure; // to access _restart_addr
|
|
491 |
// ... and for clearing cards
|
|
492 |
friend class Par_ConcMarkingClosure; // to access _restart_addr etc.
|
|
493 |
friend class MarkFromRootsVerifyClosure; // to access _restart_addr
|
|
494 |
friend class PushAndMarkVerifyClosure; // -- ditto --
|
|
495 |
friend class MarkRefsIntoAndScanClosure; // to access _overflow_list
|
|
496 |
friend class PushAndMarkClosure; // -- ditto --
|
|
497 |
friend class Par_PushAndMarkClosure; // -- ditto --
|
|
498 |
friend class CMSKeepAliveClosure; // -- ditto --
|
|
499 |
friend class CMSDrainMarkingStackClosure; // -- ditto --
|
|
500 |
friend class CMSInnerParMarkAndPushClosure; // -- ditto --
|
|
501 |
NOT_PRODUCT(friend class ScanMarkedObjectsAgainClosure;) // assertion on _overflow_list
|
|
502 |
friend class ReleaseForegroundGC; // to access _foregroundGCShouldWait
|
|
503 |
friend class VM_CMS_Operation;
|
|
504 |
friend class VM_CMS_Initial_Mark;
|
|
505 |
friend class VM_CMS_Final_Remark;
|
|
506 |
|
|
507 |
private:
|
|
508 |
jlong _time_of_last_gc;
|
|
509 |
void update_time_of_last_gc(jlong now) {
|
|
510 |
_time_of_last_gc = now;
|
|
511 |
}
|
|
512 |
|
|
513 |
OopTaskQueueSet* _task_queues;
|
|
514 |
|
|
515 |
// Overflow list of grey objects, threaded through mark-word
|
|
516 |
// Manipulated with CAS in the parallel/multi-threaded case.
|
|
517 |
oop _overflow_list;
|
|
518 |
// The following array-pair keeps track of mark words
|
|
519 |
// displaced for accomodating overflow list above.
|
|
520 |
// This code will likely be revisited under RFE#4922830.
|
|
521 |
GrowableArray<oop>* _preserved_oop_stack;
|
|
522 |
GrowableArray<markOop>* _preserved_mark_stack;
|
|
523 |
|
|
524 |
int* _hash_seed;
|
|
525 |
|
|
526 |
// In support of multi-threaded concurrent phases
|
|
527 |
YieldingFlexibleWorkGang* _conc_workers;
|
|
528 |
|
|
529 |
// Performance Counters
|
|
530 |
CollectorCounters* _gc_counters;
|
|
531 |
|
|
532 |
// Initialization Errors
|
|
533 |
bool _completed_initialization;
|
|
534 |
|
|
535 |
// In support of ExplicitGCInvokesConcurrent
|
|
536 |
static bool _full_gc_requested;
|
|
537 |
unsigned int _collection_count_start;
|
|
538 |
// Should we unload classes this concurrent cycle?
|
|
539 |
// Set in response to a concurrent full gc request.
|
|
540 |
bool _unload_classes;
|
|
541 |
bool _unloaded_classes_last_cycle;
|
|
542 |
// Did we (allow) unload classes in the previous concurrent cycle?
|
|
543 |
bool cms_unloaded_classes_last_cycle() const {
|
|
544 |
return _unloaded_classes_last_cycle || CMSClassUnloadingEnabled;
|
|
545 |
}
|
|
546 |
|
|
547 |
// Verification support
|
|
548 |
CMSBitMap _verification_mark_bm;
|
|
549 |
void verify_after_remark_work_1();
|
|
550 |
void verify_after_remark_work_2();
|
|
551 |
|
|
552 |
// true if any verification flag is on.
|
|
553 |
bool _verifying;
|
|
554 |
bool verifying() const { return _verifying; }
|
|
555 |
void set_verifying(bool v) { _verifying = v; }
|
|
556 |
|
|
557 |
// Collector policy
|
|
558 |
ConcurrentMarkSweepPolicy* _collector_policy;
|
|
559 |
ConcurrentMarkSweepPolicy* collector_policy() { return _collector_policy; }
|
|
560 |
|
|
561 |
// Check whether the gc time limit has been
|
|
562 |
// exceeded and set the size policy flag
|
|
563 |
// appropriately.
|
|
564 |
void check_gc_time_limit();
|
|
565 |
// XXX Move these to CMSStats ??? FIX ME !!!
|
|
566 |
elapsedTimer _sweep_timer;
|
|
567 |
AdaptivePaddedAverage _sweep_estimate;
|
|
568 |
|
|
569 |
protected:
|
|
570 |
ConcurrentMarkSweepGeneration* _cmsGen; // old gen (CMS)
|
|
571 |
ConcurrentMarkSweepGeneration* _permGen; // perm gen
|
|
572 |
MemRegion _span; // span covering above two
|
|
573 |
CardTableRS* _ct; // card table
|
|
574 |
|
|
575 |
// CMS marking support structures
|
|
576 |
CMSBitMap _markBitMap;
|
|
577 |
CMSBitMap _modUnionTable;
|
|
578 |
CMSMarkStack _markStack;
|
|
579 |
CMSMarkStack _revisitStack; // used to keep track of klassKlass objects
|
|
580 |
// to revisit
|
|
581 |
CMSBitMap _perm_gen_verify_bit_map; // Mark bit map for perm gen verification support.
|
|
582 |
|
|
583 |
HeapWord* _restart_addr; // in support of marking stack overflow
|
|
584 |
void lower_restart_addr(HeapWord* low);
|
|
585 |
|
|
586 |
// Counters in support of marking stack / work queue overflow handling:
|
|
587 |
// a non-zero value indicates certain types of overflow events during
|
|
588 |
// the current CMS cycle and could lead to stack resizing efforts at
|
|
589 |
// an opportune future time.
|
|
590 |
size_t _ser_pmc_preclean_ovflw;
|
|
591 |
size_t _ser_pmc_remark_ovflw;
|
|
592 |
size_t _par_pmc_remark_ovflw;
|
|
593 |
size_t _ser_kac_ovflw;
|
|
594 |
size_t _par_kac_ovflw;
|
|
595 |
NOT_PRODUCT(size_t _num_par_pushes;)
|
|
596 |
|
|
597 |
// ("Weak") Reference processing support
|
|
598 |
ReferenceProcessor* _ref_processor;
|
|
599 |
CMSIsAliveClosure _is_alive_closure;
|
|
600 |
// keep this textually after _markBitMap; c'tor dependency
|
|
601 |
|
|
602 |
ConcurrentMarkSweepThread* _cmsThread; // the thread doing the work
|
|
603 |
ModUnionClosure _modUnionClosure;
|
|
604 |
ModUnionClosurePar _modUnionClosurePar;
|
|
605 |
|
|
606 |
// CMS abstract state machine
|
|
607 |
// initial_state: Idling
|
|
608 |
// next_state(Idling) = {Marking}
|
|
609 |
// next_state(Marking) = {Precleaning, Sweeping}
|
|
610 |
// next_state(Precleaning) = {AbortablePreclean, FinalMarking}
|
|
611 |
// next_state(AbortablePreclean) = {FinalMarking}
|
|
612 |
// next_state(FinalMarking) = {Sweeping}
|
|
613 |
// next_state(Sweeping) = {Resizing}
|
|
614 |
// next_state(Resizing) = {Resetting}
|
|
615 |
// next_state(Resetting) = {Idling}
|
|
616 |
// The numeric values below are chosen so that:
|
|
617 |
// . _collectorState <= Idling == post-sweep && pre-mark
|
|
618 |
// . _collectorState in (Idling, Sweeping) == {initial,final}marking ||
|
|
619 |
// precleaning || abortablePrecleanb
|
|
620 |
enum CollectorState {
|
|
621 |
Resizing = 0,
|
|
622 |
Resetting = 1,
|
|
623 |
Idling = 2,
|
|
624 |
InitialMarking = 3,
|
|
625 |
Marking = 4,
|
|
626 |
Precleaning = 5,
|
|
627 |
AbortablePreclean = 6,
|
|
628 |
FinalMarking = 7,
|
|
629 |
Sweeping = 8
|
|
630 |
};
|
|
631 |
static CollectorState _collectorState;
|
|
632 |
|
|
633 |
// State related to prologue/epilogue invocation for my generations
|
|
634 |
bool _between_prologue_and_epilogue;
|
|
635 |
|
|
636 |
// Signalling/State related to coordination between fore- and backgroud GC
|
|
637 |
// Note: When the baton has been passed from background GC to foreground GC,
|
|
638 |
// _foregroundGCIsActive is true and _foregroundGCShouldWait is false.
|
|
639 |
static bool _foregroundGCIsActive; // true iff foreground collector is active or
|
|
640 |
// wants to go active
|
|
641 |
static bool _foregroundGCShouldWait; // true iff background GC is active and has not
|
|
642 |
// yet passed the baton to the foreground GC
|
|
643 |
|
|
644 |
// Support for CMSScheduleRemark (abortable preclean)
|
|
645 |
bool _abort_preclean;
|
|
646 |
bool _start_sampling;
|
|
647 |
|
|
648 |
int _numYields;
|
|
649 |
size_t _numDirtyCards;
|
|
650 |
uint _sweepCount;
|
|
651 |
// number of full gc's since the last concurrent gc.
|
|
652 |
uint _full_gcs_since_conc_gc;
|
|
653 |
|
|
654 |
// if occupancy exceeds this, start a new gc cycle
|
|
655 |
double _initiatingOccupancy;
|
|
656 |
// occupancy used for bootstrapping stats
|
|
657 |
double _bootstrap_occupancy;
|
|
658 |
|
|
659 |
// timer
|
|
660 |
elapsedTimer _timer;
|
|
661 |
|
|
662 |
// Timing, allocation and promotion statistics, used for scheduling.
|
|
663 |
CMSStats _stats;
|
|
664 |
|
|
665 |
// Allocation limits installed in the young gen, used only in
|
|
666 |
// CMSIncrementalMode. When an allocation in the young gen would cross one of
|
|
667 |
// these limits, the cms generation is notified and the cms thread is started
|
|
668 |
// or stopped, respectively.
|
|
669 |
HeapWord* _icms_start_limit;
|
|
670 |
HeapWord* _icms_stop_limit;
|
|
671 |
|
|
672 |
enum CMS_op_type {
|
|
673 |
CMS_op_checkpointRootsInitial,
|
|
674 |
CMS_op_checkpointRootsFinal
|
|
675 |
};
|
|
676 |
|
|
677 |
void do_CMS_operation(CMS_op_type op);
|
|
678 |
bool stop_world_and_do(CMS_op_type op);
|
|
679 |
|
|
680 |
OopTaskQueueSet* task_queues() { return _task_queues; }
|
|
681 |
int* hash_seed(int i) { return &_hash_seed[i]; }
|
|
682 |
YieldingFlexibleWorkGang* conc_workers() { return _conc_workers; }
|
|
683 |
|
|
684 |
// Support for parallelizing Eden rescan in CMS remark phase
|
|
685 |
void sample_eden(); // ... sample Eden space top
|
|
686 |
|
|
687 |
private:
|
|
688 |
// Support for parallelizing young gen rescan in CMS remark phase
|
|
689 |
Generation* _young_gen; // the younger gen
|
|
690 |
HeapWord** _top_addr; // ... Top of Eden
|
|
691 |
HeapWord** _end_addr; // ... End of Eden
|
|
692 |
HeapWord** _eden_chunk_array; // ... Eden partitioning array
|
|
693 |
size_t _eden_chunk_index; // ... top (exclusive) of array
|
|
694 |
size_t _eden_chunk_capacity; // ... max entries in array
|
|
695 |
|
|
696 |
// Support for parallelizing survivor space rescan
|
|
697 |
HeapWord** _survivor_chunk_array;
|
|
698 |
size_t _survivor_chunk_index;
|
|
699 |
size_t _survivor_chunk_capacity;
|
|
700 |
size_t* _cursor;
|
|
701 |
ChunkArray* _survivor_plab_array;
|
|
702 |
|
|
703 |
// Support for marking stack overflow handling
|
|
704 |
bool take_from_overflow_list(size_t num, CMSMarkStack* to_stack);
|
|
705 |
bool par_take_from_overflow_list(size_t num, OopTaskQueue* to_work_q);
|
|
706 |
void push_on_overflow_list(oop p);
|
|
707 |
void par_push_on_overflow_list(oop p);
|
|
708 |
// the following is, obviously, not, in general, "MT-stable"
|
|
709 |
bool overflow_list_is_empty() const;
|
|
710 |
|
|
711 |
void preserve_mark_if_necessary(oop p);
|
|
712 |
void par_preserve_mark_if_necessary(oop p);
|
|
713 |
void preserve_mark_work(oop p, markOop m);
|
|
714 |
void restore_preserved_marks_if_any();
|
|
715 |
NOT_PRODUCT(bool no_preserved_marks() const;)
|
|
716 |
// in support of testing overflow code
|
|
717 |
NOT_PRODUCT(int _overflow_counter;)
|
|
718 |
NOT_PRODUCT(bool simulate_overflow();) // sequential
|
|
719 |
NOT_PRODUCT(bool par_simulate_overflow();) // MT version
|
|
720 |
|
|
721 |
int _roots_scanning_options;
|
|
722 |
int roots_scanning_options() const { return _roots_scanning_options; }
|
|
723 |
void add_root_scanning_option(int o) { _roots_scanning_options |= o; }
|
|
724 |
void remove_root_scanning_option(int o) { _roots_scanning_options &= ~o; }
|
|
725 |
|
|
726 |
// CMS work methods
|
|
727 |
void checkpointRootsInitialWork(bool asynch); // initial checkpoint work
|
|
728 |
|
|
729 |
// a return value of false indicates failure due to stack overflow
|
|
730 |
bool markFromRootsWork(bool asynch); // concurrent marking work
|
|
731 |
|
|
732 |
public: // FIX ME!!! only for testing
|
|
733 |
bool do_marking_st(bool asynch); // single-threaded marking
|
|
734 |
bool do_marking_mt(bool asynch); // multi-threaded marking
|
|
735 |
|
|
736 |
private:
|
|
737 |
|
|
738 |
// concurrent precleaning work
|
|
739 |
size_t preclean_mod_union_table(ConcurrentMarkSweepGeneration* gen,
|
|
740 |
ScanMarkedObjectsAgainCarefullyClosure* cl);
|
|
741 |
size_t preclean_card_table(ConcurrentMarkSweepGeneration* gen,
|
|
742 |
ScanMarkedObjectsAgainCarefullyClosure* cl);
|
|
743 |
// Does precleaning work, returning a quantity indicative of
|
|
744 |
// the amount of "useful work" done.
|
|
745 |
size_t preclean_work(bool clean_refs, bool clean_survivors);
|
|
746 |
void abortable_preclean(); // Preclean while looking for possible abort
|
|
747 |
void initialize_sequential_subtasks_for_young_gen_rescan(int i);
|
|
748 |
// Helper function for above; merge-sorts the per-thread plab samples
|
|
749 |
void merge_survivor_plab_arrays(ContiguousSpace* surv);
|
|
750 |
// Resets (i.e. clears) the per-thread plab sample vectors
|
|
751 |
void reset_survivor_plab_arrays();
|
|
752 |
|
|
753 |
// final (second) checkpoint work
|
|
754 |
void checkpointRootsFinalWork(bool asynch, bool clear_all_soft_refs,
|
|
755 |
bool init_mark_was_synchronous);
|
|
756 |
// work routine for parallel version of remark
|
|
757 |
void do_remark_parallel();
|
|
758 |
// work routine for non-parallel version of remark
|
|
759 |
void do_remark_non_parallel();
|
|
760 |
// reference processing work routine (during second checkpoint)
|
|
761 |
void refProcessingWork(bool asynch, bool clear_all_soft_refs);
|
|
762 |
|
|
763 |
// concurrent sweeping work
|
|
764 |
void sweepWork(ConcurrentMarkSweepGeneration* gen, bool asynch);
|
|
765 |
|
|
766 |
// (concurrent) resetting of support data structures
|
|
767 |
void reset(bool asynch);
|
|
768 |
|
|
769 |
// Clear _expansion_cause fields of constituent generations
|
|
770 |
void clear_expansion_cause();
|
|
771 |
|
|
772 |
// An auxilliary method used to record the ends of
|
|
773 |
// used regions of each generation to limit the extent of sweep
|
|
774 |
void save_sweep_limits();
|
|
775 |
|
|
776 |
// Resize the generations included in the collector.
|
|
777 |
void compute_new_size();
|
|
778 |
|
|
779 |
// A work method used by foreground collection to determine
|
|
780 |
// what type of collection (compacting or not, continuing or fresh)
|
|
781 |
// it should do.
|
|
782 |
void decide_foreground_collection_type(bool clear_all_soft_refs,
|
|
783 |
bool* should_compact, bool* should_start_over);
|
|
784 |
|
|
785 |
// A work method used by the foreground collector to do
|
|
786 |
// a mark-sweep-compact.
|
|
787 |
void do_compaction_work(bool clear_all_soft_refs);
|
|
788 |
|
|
789 |
// A work method used by the foreground collector to do
|
|
790 |
// a mark-sweep, after taking over from a possibly on-going
|
|
791 |
// concurrent mark-sweep collection.
|
|
792 |
void do_mark_sweep_work(bool clear_all_soft_refs,
|
|
793 |
CollectorState first_state, bool should_start_over);
|
|
794 |
|
|
795 |
// If the backgrould GC is active, acquire control from the background
|
|
796 |
// GC and do the collection.
|
|
797 |
void acquire_control_and_collect(bool full, bool clear_all_soft_refs);
|
|
798 |
|
|
799 |
// For synchronizing passing of control from background to foreground
|
|
800 |
// GC. waitForForegroundGC() is called by the background
|
|
801 |
// collector. It if had to wait for a foreground collection,
|
|
802 |
// it returns true and the background collection should assume
|
|
803 |
// that the collection was finished by the foreground
|
|
804 |
// collector.
|
|
805 |
bool waitForForegroundGC();
|
|
806 |
|
|
807 |
// Incremental mode triggering: recompute the icms duty cycle and set the
|
|
808 |
// allocation limits in the young gen.
|
|
809 |
void icms_update_allocation_limits();
|
|
810 |
|
|
811 |
size_t block_size_using_printezis_bits(HeapWord* addr) const;
|
|
812 |
size_t block_size_if_printezis_bits(HeapWord* addr) const;
|
|
813 |
HeapWord* next_card_start_after_block(HeapWord* addr) const;
|
|
814 |
|
|
815 |
void setup_cms_unloading_and_verification_state();
|
|
816 |
public:
|
|
817 |
CMSCollector(ConcurrentMarkSweepGeneration* cmsGen,
|
|
818 |
ConcurrentMarkSweepGeneration* permGen,
|
|
819 |
CardTableRS* ct,
|
|
820 |
ConcurrentMarkSweepPolicy* cp);
|
|
821 |
ConcurrentMarkSweepThread* cmsThread() { return _cmsThread; }
|
|
822 |
|
|
823 |
ReferenceProcessor* ref_processor() { return _ref_processor; }
|
|
824 |
void ref_processor_init();
|
|
825 |
|
|
826 |
Mutex* bitMapLock() const { return _markBitMap.lock(); }
|
|
827 |
static CollectorState abstract_state() { return _collectorState; }
|
|
828 |
double initiatingOccupancy() const { return _initiatingOccupancy; }
|
|
829 |
|
|
830 |
bool should_abort_preclean() const; // Whether preclean should be aborted.
|
|
831 |
size_t get_eden_used() const;
|
|
832 |
size_t get_eden_capacity() const;
|
|
833 |
|
|
834 |
ConcurrentMarkSweepGeneration* cmsGen() { return _cmsGen; }
|
|
835 |
|
|
836 |
// locking checks
|
|
837 |
NOT_PRODUCT(static bool have_cms_token();)
|
|
838 |
|
|
839 |
// XXXPERM bool should_collect(bool full, size_t size, bool tlab);
|
|
840 |
bool shouldConcurrentCollect();
|
|
841 |
|
|
842 |
void collect(bool full,
|
|
843 |
bool clear_all_soft_refs,
|
|
844 |
size_t size,
|
|
845 |
bool tlab);
|
|
846 |
void collect_in_background(bool clear_all_soft_refs);
|
|
847 |
void collect_in_foreground(bool clear_all_soft_refs);
|
|
848 |
|
|
849 |
// In support of ExplicitGCInvokesConcurrent
|
|
850 |
static void request_full_gc(unsigned int full_gc_count);
|
|
851 |
// Should we unload classes in a particular concurrent cycle?
|
|
852 |
bool cms_should_unload_classes() const {
|
|
853 |
assert(!_unload_classes || ExplicitGCInvokesConcurrentAndUnloadsClasses,
|
|
854 |
"Inconsistency; see CR 6541037");
|
|
855 |
return _unload_classes || CMSClassUnloadingEnabled;
|
|
856 |
}
|
|
857 |
|
|
858 |
void direct_allocated(HeapWord* start, size_t size);
|
|
859 |
|
|
860 |
// Object is dead if not marked and current phase is sweeping.
|
|
861 |
bool is_dead_obj(oop obj) const;
|
|
862 |
|
|
863 |
// After a promotion (of "start"), do any necessary marking.
|
|
864 |
// If "par", then it's being done by a parallel GC thread.
|
|
865 |
// The last two args indicate if we need precise marking
|
|
866 |
// and if so the size of the object so it can be dirtied
|
|
867 |
// in its entirety.
|
|
868 |
void promoted(bool par, HeapWord* start,
|
|
869 |
bool is_obj_array, size_t obj_size);
|
|
870 |
|
|
871 |
HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
|
|
872 |
size_t word_size);
|
|
873 |
|
|
874 |
void getFreelistLocks() const;
|
|
875 |
void releaseFreelistLocks() const;
|
|
876 |
bool haveFreelistLocks() const;
|
|
877 |
|
|
878 |
// GC prologue and epilogue
|
|
879 |
void gc_prologue(bool full);
|
|
880 |
void gc_epilogue(bool full);
|
|
881 |
|
|
882 |
jlong time_of_last_gc(jlong now) {
|
|
883 |
if (_collectorState <= Idling) {
|
|
884 |
// gc not in progress
|
|
885 |
return _time_of_last_gc;
|
|
886 |
} else {
|
|
887 |
// collection in progress
|
|
888 |
return now;
|
|
889 |
}
|
|
890 |
}
|
|
891 |
|
|
892 |
// Support for parallel remark of survivor space
|
|
893 |
void* get_data_recorder(int thr_num);
|
|
894 |
|
|
895 |
CMSBitMap* markBitMap() { return &_markBitMap; }
|
|
896 |
void directAllocated(HeapWord* start, size_t size);
|
|
897 |
|
|
898 |
// main CMS steps and related support
|
|
899 |
void checkpointRootsInitial(bool asynch);
|
|
900 |
bool markFromRoots(bool asynch); // a return value of false indicates failure
|
|
901 |
// due to stack overflow
|
|
902 |
void preclean();
|
|
903 |
void checkpointRootsFinal(bool asynch, bool clear_all_soft_refs,
|
|
904 |
bool init_mark_was_synchronous);
|
|
905 |
void sweep(bool asynch);
|
|
906 |
|
|
907 |
// Check that the currently executing thread is the expected
|
|
908 |
// one (foreground collector or background collector).
|
|
909 |
void check_correct_thread_executing() PRODUCT_RETURN;
|
|
910 |
// XXXPERM void print_statistics() PRODUCT_RETURN;
|
|
911 |
|
|
912 |
bool is_cms_reachable(HeapWord* addr);
|
|
913 |
|
|
914 |
// Performance Counter Support
|
|
915 |
CollectorCounters* counters() { return _gc_counters; }
|
|
916 |
|
|
917 |
// timer stuff
|
|
918 |
void startTimer() { assert(!_timer.is_active(), "Error"); _timer.start(); }
|
|
919 |
void stopTimer() { assert( _timer.is_active(), "Error"); _timer.stop(); }
|
|
920 |
void resetTimer() { assert(!_timer.is_active(), "Error"); _timer.reset(); }
|
|
921 |
double timerValue() { assert(!_timer.is_active(), "Error"); return _timer.seconds(); }
|
|
922 |
|
|
923 |
int yields() { return _numYields; }
|
|
924 |
void resetYields() { _numYields = 0; }
|
|
925 |
void incrementYields() { _numYields++; }
|
|
926 |
void resetNumDirtyCards() { _numDirtyCards = 0; }
|
|
927 |
void incrementNumDirtyCards(size_t num) { _numDirtyCards += num; }
|
|
928 |
size_t numDirtyCards() { return _numDirtyCards; }
|
|
929 |
|
|
930 |
static bool foregroundGCShouldWait() { return _foregroundGCShouldWait; }
|
|
931 |
static void set_foregroundGCShouldWait(bool v) { _foregroundGCShouldWait = v; }
|
|
932 |
static bool foregroundGCIsActive() { return _foregroundGCIsActive; }
|
|
933 |
static void set_foregroundGCIsActive(bool v) { _foregroundGCIsActive = v; }
|
|
934 |
uint sweepCount() const { return _sweepCount; }
|
|
935 |
void incrementSweepCount() { _sweepCount++; }
|
|
936 |
|
|
937 |
// Timers/stats for gc scheduling and incremental mode pacing.
|
|
938 |
CMSStats& stats() { return _stats; }
|
|
939 |
|
|
940 |
// Convenience methods that check whether CMSIncrementalMode is enabled and
|
|
941 |
// forward to the corresponding methods in ConcurrentMarkSweepThread.
|
|
942 |
static void start_icms();
|
|
943 |
static void stop_icms(); // Called at the end of the cms cycle.
|
|
944 |
static void disable_icms(); // Called before a foreground collection.
|
|
945 |
static void enable_icms(); // Called after a foreground collection.
|
|
946 |
void icms_wait(); // Called at yield points.
|
|
947 |
|
|
948 |
// Adaptive size policy
|
|
949 |
CMSAdaptiveSizePolicy* size_policy();
|
|
950 |
CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters();
|
|
951 |
|
|
952 |
// debugging
|
|
953 |
void verify(bool);
|
|
954 |
bool verify_after_remark();
|
|
955 |
void verify_ok_to_terminate() const PRODUCT_RETURN;
|
|
956 |
void verify_work_stacks_empty() const PRODUCT_RETURN;
|
|
957 |
void verify_overflow_empty() const PRODUCT_RETURN;
|
|
958 |
|
|
959 |
// convenience methods in support of debugging
|
|
960 |
static const size_t skip_header_HeapWords() PRODUCT_RETURN0;
|
|
961 |
HeapWord* block_start(const void* p) const PRODUCT_RETURN0;
|
|
962 |
|
|
963 |
// accessors
|
|
964 |
CMSMarkStack* verification_mark_stack() { return &_markStack; }
|
|
965 |
CMSBitMap* verification_mark_bm() { return &_verification_mark_bm; }
|
|
966 |
|
|
967 |
// Get the bit map with a perm gen "deadness" information.
|
|
968 |
CMSBitMap* perm_gen_verify_bit_map() { return &_perm_gen_verify_bit_map; }
|
|
969 |
|
|
970 |
// Initialization errors
|
|
971 |
bool completed_initialization() { return _completed_initialization; }
|
|
972 |
};
|
|
973 |
|
|
974 |
class CMSExpansionCause : public AllStatic {
|
|
975 |
public:
|
|
976 |
enum Cause {
|
|
977 |
_no_expansion,
|
|
978 |
_satisfy_free_ratio,
|
|
979 |
_satisfy_promotion,
|
|
980 |
_satisfy_allocation,
|
|
981 |
_allocate_par_lab,
|
|
982 |
_allocate_par_spooling_space,
|
|
983 |
_adaptive_size_policy
|
|
984 |
};
|
|
985 |
// Return a string describing the cause of the expansion.
|
|
986 |
static const char* to_string(CMSExpansionCause::Cause cause);
|
|
987 |
};
|
|
988 |
|
|
989 |
class ConcurrentMarkSweepGeneration: public CardGeneration {
|
|
990 |
friend class VMStructs;
|
|
991 |
friend class ConcurrentMarkSweepThread;
|
|
992 |
friend class ConcurrentMarkSweep;
|
|
993 |
friend class CMSCollector;
|
|
994 |
protected:
|
|
995 |
static CMSCollector* _collector; // the collector that collects us
|
|
996 |
CompactibleFreeListSpace* _cmsSpace; // underlying space (only one for now)
|
|
997 |
|
|
998 |
// Performance Counters
|
|
999 |
GenerationCounters* _gen_counters;
|
|
1000 |
GSpaceCounters* _space_counters;
|
|
1001 |
|
|
1002 |
// Words directly allocated, used by CMSStats.
|
|
1003 |
size_t _direct_allocated_words;
|
|
1004 |
|
|
1005 |
// Non-product stat counters
|
|
1006 |
NOT_PRODUCT(
|
|
1007 |
int _numObjectsPromoted;
|
|
1008 |
int _numWordsPromoted;
|
|
1009 |
int _numObjectsAllocated;
|
|
1010 |
int _numWordsAllocated;
|
|
1011 |
)
|
|
1012 |
|
|
1013 |
// Used for sizing decisions
|
|
1014 |
bool _incremental_collection_failed;
|
|
1015 |
bool incremental_collection_failed() {
|
|
1016 |
return _incremental_collection_failed;
|
|
1017 |
}
|
|
1018 |
void set_incremental_collection_failed() {
|
|
1019 |
_incremental_collection_failed = true;
|
|
1020 |
}
|
|
1021 |
void clear_incremental_collection_failed() {
|
|
1022 |
_incremental_collection_failed = false;
|
|
1023 |
}
|
|
1024 |
|
|
1025 |
private:
|
|
1026 |
// For parallel young-gen GC support.
|
|
1027 |
CMSParGCThreadState** _par_gc_thread_states;
|
|
1028 |
|
|
1029 |
// Reason generation was expanded
|
|
1030 |
CMSExpansionCause::Cause _expansion_cause;
|
|
1031 |
|
|
1032 |
// accessors
|
|
1033 |
void set_expansion_cause(CMSExpansionCause::Cause v) { _expansion_cause = v;}
|
|
1034 |
CMSExpansionCause::Cause expansion_cause() { return _expansion_cause; }
|
|
1035 |
|
|
1036 |
// In support of MinChunkSize being larger than min object size
|
|
1037 |
const double _dilatation_factor;
|
|
1038 |
|
|
1039 |
enum CollectionTypes {
|
|
1040 |
Concurrent_collection_type = 0,
|
|
1041 |
MS_foreground_collection_type = 1,
|
|
1042 |
MSC_foreground_collection_type = 2,
|
|
1043 |
Unknown_collection_type = 3
|
|
1044 |
};
|
|
1045 |
|
|
1046 |
CollectionTypes _debug_collection_type;
|
|
1047 |
|
|
1048 |
protected:
|
|
1049 |
// Grow generation by specified size (returns false if unable to grow)
|
|
1050 |
bool grow_by(size_t bytes);
|
|
1051 |
// Grow generation to reserved size.
|
|
1052 |
bool grow_to_reserved();
|
|
1053 |
// Shrink generation by specified size (returns false if unable to shrink)
|
|
1054 |
virtual void shrink_by(size_t bytes);
|
|
1055 |
|
|
1056 |
// Update statistics for GC
|
|
1057 |
virtual void update_gc_stats(int level, bool full);
|
|
1058 |
|
|
1059 |
// Maximum available space in the generation (including uncommitted)
|
|
1060 |
// space.
|
|
1061 |
size_t max_available() const;
|
|
1062 |
|
|
1063 |
public:
|
|
1064 |
ConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size,
|
|
1065 |
int level, CardTableRS* ct,
|
|
1066 |
bool use_adaptive_freelists,
|
|
1067 |
FreeBlockDictionary::DictionaryChoice);
|
|
1068 |
|
|
1069 |
// Accessors
|
|
1070 |
CMSCollector* collector() const { return _collector; }
|
|
1071 |
static void set_collector(CMSCollector* collector) {
|
|
1072 |
assert(_collector == NULL, "already set");
|
|
1073 |
_collector = collector;
|
|
1074 |
}
|
|
1075 |
CompactibleFreeListSpace* cmsSpace() const { return _cmsSpace; }
|
|
1076 |
|
|
1077 |
Mutex* freelistLock() const;
|
|
1078 |
|
|
1079 |
virtual Generation::Name kind() { return Generation::ConcurrentMarkSweep; }
|
|
1080 |
|
|
1081 |
// Adaptive size policy
|
|
1082 |
CMSAdaptiveSizePolicy* size_policy();
|
|
1083 |
|
|
1084 |
bool refs_discovery_is_atomic() const { return false; }
|
|
1085 |
bool refs_discovery_is_mt() const {
|
|
1086 |
// Note: CMS does MT-discovery during the parallel-remark
|
|
1087 |
// phases. Use ReferenceProcessorMTMutator to make refs
|
|
1088 |
// discovery MT-safe during such phases or other parallel
|
|
1089 |
// discovery phases in the future. This may all go away
|
|
1090 |
// if/when we decide that refs discovery is sufficiently
|
|
1091 |
// rare that the cost of the CAS's involved is in the
|
|
1092 |
// noise. That's a measurement that should be done, and
|
|
1093 |
// the code simplified if that turns out to be the case.
|
|
1094 |
return false;
|
|
1095 |
}
|
|
1096 |
|
|
1097 |
// Override
|
|
1098 |
virtual void ref_processor_init();
|
|
1099 |
|
|
1100 |
void clear_expansion_cause() { _expansion_cause = CMSExpansionCause::_no_expansion; }
|
|
1101 |
|
|
1102 |
// Space enquiries
|
|
1103 |
size_t capacity() const;
|
|
1104 |
size_t used() const;
|
|
1105 |
size_t free() const;
|
|
1106 |
double occupancy() { return ((double)used())/((double)capacity()); }
|
|
1107 |
size_t contiguous_available() const;
|
|
1108 |
size_t unsafe_max_alloc_nogc() const;
|
|
1109 |
|
|
1110 |
// over-rides
|
|
1111 |
MemRegion used_region() const;
|
|
1112 |
MemRegion used_region_at_save_marks() const;
|
|
1113 |
|
|
1114 |
// Does a "full" (forced) collection invoked on this generation collect
|
|
1115 |
// all younger generations as well? Note that the second conjunct is a
|
|
1116 |
// hack to allow the collection of the younger gen first if the flag is
|
|
1117 |
// set. This is better than using th policy's should_collect_gen0_first()
|
|
1118 |
// since that causes us to do an extra unnecessary pair of restart-&-stop-world.
|
|
1119 |
virtual bool full_collects_younger_generations() const {
|
|
1120 |
return UseCMSCompactAtFullCollection && !CollectGen0First;
|
|
1121 |
}
|
|
1122 |
|
|
1123 |
void space_iterate(SpaceClosure* blk, bool usedOnly = false);
|
|
1124 |
|
|
1125 |
// Support for compaction
|
|
1126 |
CompactibleSpace* first_compaction_space() const;
|
|
1127 |
// Adjust quantites in the generation affected by
|
|
1128 |
// the compaction.
|
|
1129 |
void reset_after_compaction();
|
|
1130 |
|
|
1131 |
// Allocation support
|
|
1132 |
HeapWord* allocate(size_t size, bool tlab);
|
|
1133 |
HeapWord* have_lock_and_allocate(size_t size, bool tlab);
|
|
1134 |
oop promote(oop obj, size_t obj_size, oop* ref);
|
|
1135 |
HeapWord* par_allocate(size_t size, bool tlab) {
|
|
1136 |
return allocate(size, tlab);
|
|
1137 |
}
|
|
1138 |
|
|
1139 |
// Incremental mode triggering.
|
|
1140 |
HeapWord* allocation_limit_reached(Space* space, HeapWord* top,
|
|
1141 |
size_t word_size);
|
|
1142 |
|
|
1143 |
// Used by CMSStats to track direct allocation. The value is sampled and
|
|
1144 |
// reset after each young gen collection.
|
|
1145 |
size_t direct_allocated_words() const { return _direct_allocated_words; }
|
|
1146 |
void reset_direct_allocated_words() { _direct_allocated_words = 0; }
|
|
1147 |
|
|
1148 |
// Overrides for parallel promotion.
|
|
1149 |
virtual oop par_promote(int thread_num,
|
|
1150 |
oop obj, markOop m, size_t word_sz);
|
|
1151 |
// This one should not be called for CMS.
|
|
1152 |
virtual void par_promote_alloc_undo(int thread_num,
|
|
1153 |
HeapWord* obj, size_t word_sz);
|
|
1154 |
virtual void par_promote_alloc_done(int thread_num);
|
|
1155 |
virtual void par_oop_since_save_marks_iterate_done(int thread_num);
|
|
1156 |
|
|
1157 |
virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes,
|
|
1158 |
bool younger_handles_promotion_failure) const;
|
|
1159 |
|
|
1160 |
bool should_collect(bool full, size_t size, bool tlab);
|
|
1161 |
// XXXPERM
|
|
1162 |
bool shouldConcurrentCollect(double initiatingOccupancy); // XXXPERM
|
|
1163 |
void collect(bool full,
|
|
1164 |
bool clear_all_soft_refs,
|
|
1165 |
size_t size,
|
|
1166 |
bool tlab);
|
|
1167 |
|
|
1168 |
HeapWord* expand_and_allocate(size_t word_size,
|
|
1169 |
bool tlab,
|
|
1170 |
bool parallel = false);
|
|
1171 |
|
|
1172 |
// GC prologue and epilogue
|
|
1173 |
void gc_prologue(bool full);
|
|
1174 |
void gc_prologue_work(bool full, bool registerClosure,
|
|
1175 |
ModUnionClosure* modUnionClosure);
|
|
1176 |
void gc_epilogue(bool full);
|
|
1177 |
void gc_epilogue_work(bool full);
|
|
1178 |
|
|
1179 |
// Time since last GC of this generation
|
|
1180 |
jlong time_of_last_gc(jlong now) {
|
|
1181 |
return collector()->time_of_last_gc(now);
|
|
1182 |
}
|
|
1183 |
void update_time_of_last_gc(jlong now) {
|
|
1184 |
collector()-> update_time_of_last_gc(now);
|
|
1185 |
}
|
|
1186 |
|
|
1187 |
// Allocation failure
|
|
1188 |
void expand(size_t bytes, size_t expand_bytes,
|
|
1189 |
CMSExpansionCause::Cause cause);
|
|
1190 |
void shrink(size_t bytes);
|
|
1191 |
HeapWord* expand_and_par_lab_allocate(CMSParGCThreadState* ps, size_t word_sz);
|
|
1192 |
bool expand_and_ensure_spooling_space(PromotionInfo* promo);
|
|
1193 |
|
|
1194 |
// Iteration support and related enquiries
|
|
1195 |
void save_marks();
|
|
1196 |
bool no_allocs_since_save_marks();
|
|
1197 |
void object_iterate_since_last_GC(ObjectClosure* cl);
|
|
1198 |
void younger_refs_iterate(OopsInGenClosure* cl);
|
|
1199 |
|
|
1200 |
// Iteration support specific to CMS generations
|
|
1201 |
void save_sweep_limit();
|
|
1202 |
|
|
1203 |
// More iteration support
|
|
1204 |
virtual void oop_iterate(MemRegion mr, OopClosure* cl);
|
|
1205 |
virtual void oop_iterate(OopClosure* cl);
|
|
1206 |
virtual void object_iterate(ObjectClosure* cl);
|
|
1207 |
|
|
1208 |
// Need to declare the full complement of closures, whether we'll
|
|
1209 |
// override them or not, or get message from the compiler:
|
|
1210 |
// oop_since_save_marks_iterate_nv hides virtual function...
|
|
1211 |
#define CMS_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
|
|
1212 |
void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
|
|
1213 |
ALL_SINCE_SAVE_MARKS_CLOSURES(CMS_SINCE_SAVE_MARKS_DECL)
|
|
1214 |
|
|
1215 |
// Smart allocation XXX -- move to CFLSpace?
|
|
1216 |
void setNearLargestChunk();
|
|
1217 |
bool isNearLargestChunk(HeapWord* addr);
|
|
1218 |
|
|
1219 |
// Get the chunk at the end of the space. Delagates to
|
|
1220 |
// the space.
|
|
1221 |
FreeChunk* find_chunk_at_end();
|
|
1222 |
|
|
1223 |
// Overriding of unused functionality (sharing not yet supported with CMS)
|
|
1224 |
void pre_adjust_pointers();
|
|
1225 |
void post_compact();
|
|
1226 |
|
|
1227 |
// Debugging
|
|
1228 |
void prepare_for_verify();
|
|
1229 |
void verify(bool allow_dirty);
|
|
1230 |
void print_statistics() PRODUCT_RETURN;
|
|
1231 |
|
|
1232 |
// Performance Counters support
|
|
1233 |
virtual void update_counters();
|
|
1234 |
virtual void update_counters(size_t used);
|
|
1235 |
void initialize_performance_counters();
|
|
1236 |
CollectorCounters* counters() { return collector()->counters(); }
|
|
1237 |
|
|
1238 |
// Support for parallel remark of survivor space
|
|
1239 |
void* get_data_recorder(int thr_num) {
|
|
1240 |
//Delegate to collector
|
|
1241 |
return collector()->get_data_recorder(thr_num);
|
|
1242 |
}
|
|
1243 |
|
|
1244 |
// Printing
|
|
1245 |
const char* name() const;
|
|
1246 |
virtual const char* short_name() const { return "CMS"; }
|
|
1247 |
void print() const;
|
|
1248 |
void printOccupancy(const char* s);
|
|
1249 |
bool must_be_youngest() const { return false; }
|
|
1250 |
bool must_be_oldest() const { return true; }
|
|
1251 |
|
|
1252 |
void compute_new_size();
|
|
1253 |
|
|
1254 |
CollectionTypes debug_collection_type() { return _debug_collection_type; }
|
|
1255 |
void rotate_debug_collection_type();
|
|
1256 |
};
|
|
1257 |
|
|
1258 |
class ASConcurrentMarkSweepGeneration : public ConcurrentMarkSweepGeneration {
|
|
1259 |
|
|
1260 |
// Return the size policy from the heap's collector
|
|
1261 |
// policy casted to CMSAdaptiveSizePolicy*.
|
|
1262 |
CMSAdaptiveSizePolicy* cms_size_policy() const;
|
|
1263 |
|
|
1264 |
// Resize the generation based on the adaptive size
|
|
1265 |
// policy.
|
|
1266 |
void resize(size_t cur_promo, size_t desired_promo);
|
|
1267 |
|
|
1268 |
// Return the GC counters from the collector policy
|
|
1269 |
CMSGCAdaptivePolicyCounters* gc_adaptive_policy_counters();
|
|
1270 |
|
|
1271 |
virtual void shrink_by(size_t bytes);
|
|
1272 |
|
|
1273 |
public:
|
|
1274 |
virtual void compute_new_size();
|
|
1275 |
ASConcurrentMarkSweepGeneration(ReservedSpace rs, size_t initial_byte_size,
|
|
1276 |
int level, CardTableRS* ct,
|
|
1277 |
bool use_adaptive_freelists,
|
|
1278 |
FreeBlockDictionary::DictionaryChoice
|
|
1279 |
dictionaryChoice) :
|
|
1280 |
ConcurrentMarkSweepGeneration(rs, initial_byte_size, level, ct,
|
|
1281 |
use_adaptive_freelists, dictionaryChoice) {}
|
|
1282 |
|
|
1283 |
virtual const char* short_name() const { return "ASCMS"; }
|
|
1284 |
virtual Generation::Name kind() { return Generation::ASConcurrentMarkSweep; }
|
|
1285 |
|
|
1286 |
virtual void update_counters();
|
|
1287 |
virtual void update_counters(size_t used);
|
|
1288 |
};
|
|
1289 |
|
|
1290 |
//
|
|
1291 |
// Closures of various sorts used by CMS to accomplish its work
|
|
1292 |
//
|
|
1293 |
|
|
1294 |
// This closure is used to check that a certain set of oops is empty.
|
|
1295 |
class FalseClosure: public OopClosure {
|
|
1296 |
public:
|
|
1297 |
void do_oop(oop* p) {
|
|
1298 |
guarantee(false, "Should be an empty set");
|
|
1299 |
}
|
|
1300 |
};
|
|
1301 |
|
|
1302 |
// This closure is used to do concurrent marking from the roots
|
|
1303 |
// following the first checkpoint.
|
|
1304 |
class MarkFromRootsClosure: public BitMapClosure {
|
|
1305 |
CMSCollector* _collector;
|
|
1306 |
MemRegion _span;
|
|
1307 |
CMSBitMap* _bitMap;
|
|
1308 |
CMSBitMap* _mut;
|
|
1309 |
CMSMarkStack* _markStack;
|
|
1310 |
CMSMarkStack* _revisitStack;
|
|
1311 |
bool _yield;
|
|
1312 |
int _skipBits;
|
|
1313 |
HeapWord* _finger;
|
|
1314 |
HeapWord* _threshold;
|
|
1315 |
DEBUG_ONLY(bool _verifying;)
|
|
1316 |
|
|
1317 |
public:
|
|
1318 |
MarkFromRootsClosure(CMSCollector* collector, MemRegion span,
|
|
1319 |
CMSBitMap* bitMap,
|
|
1320 |
CMSMarkStack* markStack,
|
|
1321 |
CMSMarkStack* revisitStack,
|
|
1322 |
bool should_yield, bool verifying = false);
|
|
1323 |
void do_bit(size_t offset);
|
|
1324 |
void reset(HeapWord* addr);
|
|
1325 |
inline void do_yield_check();
|
|
1326 |
|
|
1327 |
private:
|
|
1328 |
void scanOopsInOop(HeapWord* ptr);
|
|
1329 |
void do_yield_work();
|
|
1330 |
};
|
|
1331 |
|
|
1332 |
// This closure is used to do concurrent multi-threaded
|
|
1333 |
// marking from the roots following the first checkpoint.
|
|
1334 |
// XXX This should really be a subclass of The serial version
|
|
1335 |
// above, but i have not had the time to refactor things cleanly.
|
|
1336 |
// That willbe done for Dolphin.
|
|
1337 |
class Par_MarkFromRootsClosure: public BitMapClosure {
|
|
1338 |
CMSCollector* _collector;
|
|
1339 |
MemRegion _whole_span;
|
|
1340 |
MemRegion _span;
|
|
1341 |
CMSBitMap* _bit_map;
|
|
1342 |
CMSBitMap* _mut;
|
|
1343 |
OopTaskQueue* _work_queue;
|
|
1344 |
CMSMarkStack* _overflow_stack;
|
|
1345 |
CMSMarkStack* _revisit_stack;
|
|
1346 |
bool _yield;
|
|
1347 |
int _skip_bits;
|
|
1348 |
HeapWord* _finger;
|
|
1349 |
HeapWord* _threshold;
|
|
1350 |
CMSConcMarkingTask* _task;
|
|
1351 |
public:
|
|
1352 |
Par_MarkFromRootsClosure(CMSConcMarkingTask* task, CMSCollector* collector,
|
|
1353 |
MemRegion span,
|
|
1354 |
CMSBitMap* bit_map,
|
|
1355 |
OopTaskQueue* work_queue,
|
|
1356 |
CMSMarkStack* overflow_stack,
|
|
1357 |
CMSMarkStack* revisit_stack,
|
|
1358 |
bool should_yield);
|
|
1359 |
void do_bit(size_t offset);
|
|
1360 |
inline void do_yield_check();
|
|
1361 |
|
|
1362 |
private:
|
|
1363 |
void scan_oops_in_oop(HeapWord* ptr);
|
|
1364 |
void do_yield_work();
|
|
1365 |
bool get_work_from_overflow_stack();
|
|
1366 |
};
|
|
1367 |
|
|
1368 |
// The following closures are used to do certain kinds of verification of
|
|
1369 |
// CMS marking.
|
|
1370 |
class PushAndMarkVerifyClosure: public OopClosure {
|
|
1371 |
CMSCollector* _collector;
|
|
1372 |
MemRegion _span;
|
|
1373 |
CMSBitMap* _verification_bm;
|
|
1374 |
CMSBitMap* _cms_bm;
|
|
1375 |
CMSMarkStack* _mark_stack;
|
|
1376 |
public:
|
|
1377 |
PushAndMarkVerifyClosure(CMSCollector* cms_collector,
|
|
1378 |
MemRegion span,
|
|
1379 |
CMSBitMap* verification_bm,
|
|
1380 |
CMSBitMap* cms_bm,
|
|
1381 |
CMSMarkStack* mark_stack);
|
|
1382 |
void do_oop(oop* p);
|
|
1383 |
// Deal with a stack overflow condition
|
|
1384 |
void handle_stack_overflow(HeapWord* lost);
|
|
1385 |
};
|
|
1386 |
|
|
1387 |
class MarkFromRootsVerifyClosure: public BitMapClosure {
|
|
1388 |
CMSCollector* _collector;
|
|
1389 |
MemRegion _span;
|
|
1390 |
CMSBitMap* _verification_bm;
|
|
1391 |
CMSBitMap* _cms_bm;
|
|
1392 |
CMSMarkStack* _mark_stack;
|
|
1393 |
HeapWord* _finger;
|
|
1394 |
PushAndMarkVerifyClosure _pam_verify_closure;
|
|
1395 |
public:
|
|
1396 |
MarkFromRootsVerifyClosure(CMSCollector* collector, MemRegion span,
|
|
1397 |
CMSBitMap* verification_bm,
|
|
1398 |
CMSBitMap* cms_bm,
|
|
1399 |
CMSMarkStack* mark_stack);
|
|
1400 |
void do_bit(size_t offset);
|
|
1401 |
void reset(HeapWord* addr);
|
|
1402 |
};
|
|
1403 |
|
|
1404 |
|
|
1405 |
// This closure is used to check that a certain set of bits is
|
|
1406 |
// "empty" (i.e. the bit vector doesn't have any 1-bits).
|
|
1407 |
class FalseBitMapClosure: public BitMapClosure {
|
|
1408 |
public:
|
|
1409 |
void do_bit(size_t offset) {
|
|
1410 |
guarantee(false, "Should not have a 1 bit");
|
|
1411 |
}
|
|
1412 |
};
|
|
1413 |
|
|
1414 |
// This closure is used during the second checkpointing phase
|
|
1415 |
// to rescan the marked objects on the dirty cards in the mod
|
|
1416 |
// union table and the card table proper. It's invoked via
|
|
1417 |
// MarkFromDirtyCardsClosure below. It uses either
|
|
1418 |
// [Par_]MarkRefsIntoAndScanClosure (Par_ in the parallel case)
|
|
1419 |
// declared in genOopClosures.hpp to accomplish some of its work.
|
|
1420 |
// In the parallel case the bitMap is shared, so access to
|
|
1421 |
// it needs to be suitably synchronized for updates by embedded
|
|
1422 |
// closures that update it; however, this closure itself only
|
|
1423 |
// reads the bit_map and because it is idempotent, is immune to
|
|
1424 |
// reading stale values.
|
|
1425 |
class ScanMarkedObjectsAgainClosure: public UpwardsObjectClosure {
|
|
1426 |
#ifdef ASSERT
|
|
1427 |
CMSCollector* _collector;
|
|
1428 |
MemRegion _span;
|
|
1429 |
union {
|
|
1430 |
CMSMarkStack* _mark_stack;
|
|
1431 |
OopTaskQueue* _work_queue;
|
|
1432 |
};
|
|
1433 |
#endif // ASSERT
|
|
1434 |
bool _parallel;
|
|
1435 |
CMSBitMap* _bit_map;
|
|
1436 |
union {
|
|
1437 |
MarkRefsIntoAndScanClosure* _scan_closure;
|
|
1438 |
Par_MarkRefsIntoAndScanClosure* _par_scan_closure;
|
|
1439 |
};
|
|
1440 |
|
|
1441 |
public:
|
|
1442 |
ScanMarkedObjectsAgainClosure(CMSCollector* collector,
|
|
1443 |
MemRegion span,
|
|
1444 |
ReferenceProcessor* rp,
|
|
1445 |
CMSBitMap* bit_map,
|
|
1446 |
CMSMarkStack* mark_stack,
|
|
1447 |
CMSMarkStack* revisit_stack,
|
|
1448 |
MarkRefsIntoAndScanClosure* cl):
|
|
1449 |
#ifdef ASSERT
|
|
1450 |
_collector(collector),
|
|
1451 |
_span(span),
|
|
1452 |
_mark_stack(mark_stack),
|
|
1453 |
#endif // ASSERT
|
|
1454 |
_parallel(false),
|
|
1455 |
_bit_map(bit_map),
|
|
1456 |
_scan_closure(cl) { }
|
|
1457 |
|
|
1458 |
ScanMarkedObjectsAgainClosure(CMSCollector* collector,
|
|
1459 |
MemRegion span,
|
|
1460 |
ReferenceProcessor* rp,
|
|
1461 |
CMSBitMap* bit_map,
|
|
1462 |
OopTaskQueue* work_queue,
|
|
1463 |
CMSMarkStack* revisit_stack,
|
|
1464 |
Par_MarkRefsIntoAndScanClosure* cl):
|
|
1465 |
#ifdef ASSERT
|
|
1466 |
_collector(collector),
|
|
1467 |
_span(span),
|
|
1468 |
_work_queue(work_queue),
|
|
1469 |
#endif // ASSERT
|
|
1470 |
_parallel(true),
|
|
1471 |
_bit_map(bit_map),
|
|
1472 |
_par_scan_closure(cl) { }
|
|
1473 |
|
|
1474 |
void do_object(oop obj) {
|
|
1475 |
guarantee(false, "Call do_object_b(oop, MemRegion) instead");
|
|
1476 |
}
|
|
1477 |
bool do_object_b(oop obj) {
|
|
1478 |
guarantee(false, "Call do_object_b(oop, MemRegion) form instead");
|
|
1479 |
return false;
|
|
1480 |
}
|
|
1481 |
bool do_object_bm(oop p, MemRegion mr);
|
|
1482 |
};
|
|
1483 |
|
|
1484 |
// This closure is used during the second checkpointing phase
|
|
1485 |
// to rescan the marked objects on the dirty cards in the mod
|
|
1486 |
// union table and the card table proper. It invokes
|
|
1487 |
// ScanMarkedObjectsAgainClosure above to accomplish much of its work.
|
|
1488 |
// In the parallel case, the bit map is shared and requires
|
|
1489 |
// synchronized access.
|
|
1490 |
class MarkFromDirtyCardsClosure: public MemRegionClosure {
|
|
1491 |
CompactibleFreeListSpace* _space;
|
|
1492 |
ScanMarkedObjectsAgainClosure _scan_cl;
|
|
1493 |
size_t _num_dirty_cards;
|
|
1494 |
|
|
1495 |
public:
|
|
1496 |
MarkFromDirtyCardsClosure(CMSCollector* collector,
|
|
1497 |
MemRegion span,
|
|
1498 |
CompactibleFreeListSpace* space,
|
|
1499 |
CMSBitMap* bit_map,
|
|
1500 |
CMSMarkStack* mark_stack,
|
|
1501 |
CMSMarkStack* revisit_stack,
|
|
1502 |
MarkRefsIntoAndScanClosure* cl):
|
|
1503 |
_space(space),
|
|
1504 |
_num_dirty_cards(0),
|
|
1505 |
_scan_cl(collector, span, collector->ref_processor(), bit_map,
|
|
1506 |
mark_stack, revisit_stack, cl) { }
|
|
1507 |
|
|
1508 |
MarkFromDirtyCardsClosure(CMSCollector* collector,
|
|
1509 |
MemRegion span,
|
|
1510 |
CompactibleFreeListSpace* space,
|
|
1511 |
CMSBitMap* bit_map,
|
|
1512 |
OopTaskQueue* work_queue,
|
|
1513 |
CMSMarkStack* revisit_stack,
|
|
1514 |
Par_MarkRefsIntoAndScanClosure* cl):
|
|
1515 |
_space(space),
|
|
1516 |
_num_dirty_cards(0),
|
|
1517 |
_scan_cl(collector, span, collector->ref_processor(), bit_map,
|
|
1518 |
work_queue, revisit_stack, cl) { }
|
|
1519 |
|
|
1520 |
void do_MemRegion(MemRegion mr);
|
|
1521 |
void set_space(CompactibleFreeListSpace* space) { _space = space; }
|
|
1522 |
size_t num_dirty_cards() { return _num_dirty_cards; }
|
|
1523 |
};
|
|
1524 |
|
|
1525 |
// This closure is used in the non-product build to check
|
|
1526 |
// that there are no MemRegions with a certain property.
|
|
1527 |
class FalseMemRegionClosure: public MemRegionClosure {
|
|
1528 |
void do_MemRegion(MemRegion mr) {
|
|
1529 |
guarantee(!mr.is_empty(), "Shouldn't be empty");
|
|
1530 |
guarantee(false, "Should never be here");
|
|
1531 |
}
|
|
1532 |
};
|
|
1533 |
|
|
1534 |
// This closure is used during the precleaning phase
|
|
1535 |
// to "carefully" rescan marked objects on dirty cards.
|
|
1536 |
// It uses MarkRefsIntoAndScanClosure declared in genOopClosures.hpp
|
|
1537 |
// to accomplish some of its work.
|
|
1538 |
class ScanMarkedObjectsAgainCarefullyClosure: public ObjectClosureCareful {
|
|
1539 |
CMSCollector* _collector;
|
|
1540 |
MemRegion _span;
|
|
1541 |
bool _yield;
|
|
1542 |
Mutex* _freelistLock;
|
|
1543 |
CMSBitMap* _bitMap;
|
|
1544 |
CMSMarkStack* _markStack;
|
|
1545 |
MarkRefsIntoAndScanClosure* _scanningClosure;
|
|
1546 |
|
|
1547 |
public:
|
|
1548 |
ScanMarkedObjectsAgainCarefullyClosure(CMSCollector* collector,
|
|
1549 |
MemRegion span,
|
|
1550 |
CMSBitMap* bitMap,
|
|
1551 |
CMSMarkStack* markStack,
|
|
1552 |
CMSMarkStack* revisitStack,
|
|
1553 |
MarkRefsIntoAndScanClosure* cl,
|
|
1554 |
bool should_yield):
|
|
1555 |
_collector(collector),
|
|
1556 |
_span(span),
|
|
1557 |
_yield(should_yield),
|
|
1558 |
_bitMap(bitMap),
|
|
1559 |
_markStack(markStack),
|
|
1560 |
_scanningClosure(cl) {
|
|
1561 |
}
|
|
1562 |
|
|
1563 |
void do_object(oop p) {
|
|
1564 |
guarantee(false, "call do_object_careful instead");
|
|
1565 |
}
|
|
1566 |
|
|
1567 |
size_t do_object_careful(oop p) {
|
|
1568 |
guarantee(false, "Unexpected caller");
|
|
1569 |
return 0;
|
|
1570 |
}
|
|
1571 |
|
|
1572 |
size_t do_object_careful_m(oop p, MemRegion mr);
|
|
1573 |
|
|
1574 |
void setFreelistLock(Mutex* m) {
|
|
1575 |
_freelistLock = m;
|
|
1576 |
_scanningClosure->set_freelistLock(m);
|
|
1577 |
}
|
|
1578 |
|
|
1579 |
private:
|
|
1580 |
inline bool do_yield_check();
|
|
1581 |
|
|
1582 |
void do_yield_work();
|
|
1583 |
};
|
|
1584 |
|
|
1585 |
class SurvivorSpacePrecleanClosure: public ObjectClosureCareful {
|
|
1586 |
CMSCollector* _collector;
|
|
1587 |
MemRegion _span;
|
|
1588 |
bool _yield;
|
|
1589 |
CMSBitMap* _bit_map;
|
|
1590 |
CMSMarkStack* _mark_stack;
|
|
1591 |
PushAndMarkClosure* _scanning_closure;
|
|
1592 |
unsigned int _before_count;
|
|
1593 |
|
|
1594 |
public:
|
|
1595 |
SurvivorSpacePrecleanClosure(CMSCollector* collector,
|
|
1596 |
MemRegion span,
|
|
1597 |
CMSBitMap* bit_map,
|
|
1598 |
CMSMarkStack* mark_stack,
|
|
1599 |
PushAndMarkClosure* cl,
|
|
1600 |
unsigned int before_count,
|
|
1601 |
bool should_yield):
|
|
1602 |
_collector(collector),
|
|
1603 |
_span(span),
|
|
1604 |
_yield(should_yield),
|
|
1605 |
_bit_map(bit_map),
|
|
1606 |
_mark_stack(mark_stack),
|
|
1607 |
_scanning_closure(cl),
|
|
1608 |
_before_count(before_count)
|
|
1609 |
{ }
|
|
1610 |
|
|
1611 |
void do_object(oop p) {
|
|
1612 |
guarantee(false, "call do_object_careful instead");
|
|
1613 |
}
|
|
1614 |
|
|
1615 |
size_t do_object_careful(oop p);
|
|
1616 |
|
|
1617 |
size_t do_object_careful_m(oop p, MemRegion mr) {
|
|
1618 |
guarantee(false, "Unexpected caller");
|
|
1619 |
return 0;
|
|
1620 |
}
|
|
1621 |
|
|
1622 |
private:
|
|
1623 |
inline void do_yield_check();
|
|
1624 |
void do_yield_work();
|
|
1625 |
};
|
|
1626 |
|
|
1627 |
// This closure is used to accomplish the sweeping work
|
|
1628 |
// after the second checkpoint but before the concurrent reset
|
|
1629 |
// phase.
|
|
1630 |
//
|
|
1631 |
// Terminology
|
|
1632 |
// left hand chunk (LHC) - block of one or more chunks currently being
|
|
1633 |
// coalesced. The LHC is available for coalescing with a new chunk.
|
|
1634 |
// right hand chunk (RHC) - block that is currently being swept that is
|
|
1635 |
// free or garbage that can be coalesced with the LHC.
|
|
1636 |
// _inFreeRange is true if there is currently a LHC
|
|
1637 |
// _lastFreeRangeCoalesced is true if the LHC consists of more than one chunk.
|
|
1638 |
// _freeRangeInFreeLists is true if the LHC is in the free lists.
|
|
1639 |
// _freeFinger is the address of the current LHC
|
|
1640 |
class SweepClosure: public BlkClosureCareful {
|
|
1641 |
CMSCollector* _collector; // collector doing the work
|
|
1642 |
ConcurrentMarkSweepGeneration* _g; // Generation being swept
|
|
1643 |
CompactibleFreeListSpace* _sp; // Space being swept
|
|
1644 |
HeapWord* _limit;
|
|
1645 |
Mutex* _freelistLock; // Free list lock (in space)
|
|
1646 |
CMSBitMap* _bitMap; // Marking bit map (in
|
|
1647 |
// generation)
|
|
1648 |
bool _inFreeRange; // Indicates if we are in the
|
|
1649 |
// midst of a free run
|
|
1650 |
bool _freeRangeInFreeLists;
|
|
1651 |
// Often, we have just found
|
|
1652 |
// a free chunk and started
|
|
1653 |
// a new free range; we do not
|
|
1654 |
// eagerly remove this chunk from
|
|
1655 |
// the free lists unless there is
|
|
1656 |
// a possibility of coalescing.
|
|
1657 |
// When true, this flag indicates
|
|
1658 |
// that the _freeFinger below
|
|
1659 |
// points to a potentially free chunk
|
|
1660 |
// that may still be in the free lists
|
|
1661 |
bool _lastFreeRangeCoalesced;
|
|
1662 |
// free range contains chunks
|
|
1663 |
// coalesced
|
|
1664 |
bool _yield;
|
|
1665 |
// Whether sweeping should be
|
|
1666 |
// done with yields. For instance
|
|
1667 |
// when done by the foreground
|
|
1668 |
// collector we shouldn't yield.
|
|
1669 |
HeapWord* _freeFinger; // When _inFreeRange is set, the
|
|
1670 |
// pointer to the "left hand
|
|
1671 |
// chunk"
|
|
1672 |
size_t _freeRangeSize;
|
|
1673 |
// When _inFreeRange is set, this
|
|
1674 |
// indicates the accumulated size
|
|
1675 |
// of the "left hand chunk"
|
|
1676 |
NOT_PRODUCT(
|
|
1677 |
size_t _numObjectsFreed;
|
|
1678 |
size_t _numWordsFreed;
|
|
1679 |
size_t _numObjectsLive;
|
|
1680 |
size_t _numWordsLive;
|
|
1681 |
size_t _numObjectsAlreadyFree;
|
|
1682 |
size_t _numWordsAlreadyFree;
|
|
1683 |
FreeChunk* _last_fc;
|
|
1684 |
)
|
|
1685 |
private:
|
|
1686 |
// Code that is common to a free chunk or garbage when
|
|
1687 |
// encountered during sweeping.
|
|
1688 |
void doPostIsFreeOrGarbageChunk(FreeChunk *fc,
|
|
1689 |
size_t chunkSize);
|
|
1690 |
// Process a free chunk during sweeping.
|
|
1691 |
void doAlreadyFreeChunk(FreeChunk *fc);
|
|
1692 |
// Process a garbage chunk during sweeping.
|
|
1693 |
size_t doGarbageChunk(FreeChunk *fc);
|
|
1694 |
// Process a live chunk during sweeping.
|
|
1695 |
size_t doLiveChunk(FreeChunk* fc);
|
|
1696 |
|
|
1697 |
// Accessors.
|
|
1698 |
HeapWord* freeFinger() const { return _freeFinger; }
|
|
1699 |
void set_freeFinger(HeapWord* v) { _freeFinger = v; }
|
|
1700 |
size_t freeRangeSize() const { return _freeRangeSize; }
|
|
1701 |
void set_freeRangeSize(size_t v) { _freeRangeSize = v; }
|
|
1702 |
bool inFreeRange() const { return _inFreeRange; }
|
|
1703 |
void set_inFreeRange(bool v) { _inFreeRange = v; }
|
|
1704 |
bool lastFreeRangeCoalesced() const { return _lastFreeRangeCoalesced; }
|
|
1705 |
void set_lastFreeRangeCoalesced(bool v) { _lastFreeRangeCoalesced = v; }
|
|
1706 |
bool freeRangeInFreeLists() const { return _freeRangeInFreeLists; }
|
|
1707 |
void set_freeRangeInFreeLists(bool v) { _freeRangeInFreeLists = v; }
|
|
1708 |
|
|
1709 |
// Initialize a free range.
|
|
1710 |
void initialize_free_range(HeapWord* freeFinger, bool freeRangeInFreeLists);
|
|
1711 |
// Return this chunk to the free lists.
|
|
1712 |
void flushCurFreeChunk(HeapWord* chunk, size_t size);
|
|
1713 |
|
|
1714 |
// Check if we should yield and do so when necessary.
|
|
1715 |
inline void do_yield_check(HeapWord* addr);
|
|
1716 |
|
|
1717 |
// Yield
|
|
1718 |
void do_yield_work(HeapWord* addr);
|
|
1719 |
|
|
1720 |
// Debugging/Printing
|
|
1721 |
void record_free_block_coalesced(FreeChunk* fc) const PRODUCT_RETURN;
|
|
1722 |
|
|
1723 |
public:
|
|
1724 |
SweepClosure(CMSCollector* collector, ConcurrentMarkSweepGeneration* g,
|
|
1725 |
CMSBitMap* bitMap, bool should_yield);
|
|
1726 |
~SweepClosure();
|
|
1727 |
|
|
1728 |
size_t do_blk_careful(HeapWord* addr);
|
|
1729 |
};
|
|
1730 |
|
|
1731 |
// Closures related to weak references processing
|
|
1732 |
|
|
1733 |
// During CMS' weak reference processing, this is a
|
|
1734 |
// work-routine/closure used to complete transitive
|
|
1735 |
// marking of objects as live after a certain point
|
|
1736 |
// in which an initial set has been completely accumulated.
|
|
1737 |
class CMSDrainMarkingStackClosure: public VoidClosure {
|
|
1738 |
CMSCollector* _collector;
|
|
1739 |
MemRegion _span;
|
|
1740 |
CMSMarkStack* _mark_stack;
|
|
1741 |
CMSBitMap* _bit_map;
|
|
1742 |
CMSKeepAliveClosure* _keep_alive;
|
|
1743 |
public:
|
|
1744 |
CMSDrainMarkingStackClosure(CMSCollector* collector, MemRegion span,
|
|
1745 |
CMSBitMap* bit_map, CMSMarkStack* mark_stack,
|
|
1746 |
CMSKeepAliveClosure* keep_alive):
|
|
1747 |
_collector(collector),
|
|
1748 |
_span(span),
|
|
1749 |
_bit_map(bit_map),
|
|
1750 |
_mark_stack(mark_stack),
|
|
1751 |
_keep_alive(keep_alive) { }
|
|
1752 |
|
|
1753 |
void do_void();
|
|
1754 |
};
|
|
1755 |
|
|
1756 |
// A parallel version of CMSDrainMarkingStackClosure above.
|
|
1757 |
class CMSParDrainMarkingStackClosure: public VoidClosure {
|
|
1758 |
CMSCollector* _collector;
|
|
1759 |
MemRegion _span;
|
|
1760 |
OopTaskQueue* _work_queue;
|
|
1761 |
CMSBitMap* _bit_map;
|
|
1762 |
CMSInnerParMarkAndPushClosure _mark_and_push;
|
|
1763 |
|
|
1764 |
public:
|
|
1765 |
CMSParDrainMarkingStackClosure(CMSCollector* collector,
|
|
1766 |
MemRegion span, CMSBitMap* bit_map,
|
|
1767 |
OopTaskQueue* work_queue):
|
|
1768 |
_collector(collector),
|
|
1769 |
_span(span),
|
|
1770 |
_bit_map(bit_map),
|
|
1771 |
_work_queue(work_queue),
|
|
1772 |
_mark_and_push(collector, span, bit_map, work_queue) { }
|
|
1773 |
|
|
1774 |
public:
|
|
1775 |
void trim_queue(uint max);
|
|
1776 |
void do_void();
|
|
1777 |
};
|
|
1778 |
|
|
1779 |
// Allow yielding or short-circuiting of reference list
|
|
1780 |
// prelceaning work.
|
|
1781 |
class CMSPrecleanRefsYieldClosure: public YieldClosure {
|
|
1782 |
CMSCollector* _collector;
|
|
1783 |
void do_yield_work();
|
|
1784 |
public:
|
|
1785 |
CMSPrecleanRefsYieldClosure(CMSCollector* collector):
|
|
1786 |
_collector(collector) {}
|
|
1787 |
virtual bool should_return();
|
|
1788 |
};
|
|
1789 |
|
|
1790 |
|
|
1791 |
// Convenience class that locks free list locks for given CMS collector
|
|
1792 |
class FreelistLocker: public StackObj {
|
|
1793 |
private:
|
|
1794 |
CMSCollector* _collector;
|
|
1795 |
public:
|
|
1796 |
FreelistLocker(CMSCollector* collector):
|
|
1797 |
_collector(collector) {
|
|
1798 |
_collector->getFreelistLocks();
|
|
1799 |
}
|
|
1800 |
|
|
1801 |
~FreelistLocker() {
|
|
1802 |
_collector->releaseFreelistLocks();
|
|
1803 |
}
|
|
1804 |
};
|
|
1805 |
|
|
1806 |
// Mark all dead objects in a given space.
|
|
1807 |
class MarkDeadObjectsClosure: public BlkClosure {
|
|
1808 |
const CMSCollector* _collector;
|
|
1809 |
const CompactibleFreeListSpace* _sp;
|
|
1810 |
CMSBitMap* _live_bit_map;
|
|
1811 |
CMSBitMap* _dead_bit_map;
|
|
1812 |
public:
|
|
1813 |
MarkDeadObjectsClosure(const CMSCollector* collector,
|
|
1814 |
const CompactibleFreeListSpace* sp,
|
|
1815 |
CMSBitMap *live_bit_map,
|
|
1816 |
CMSBitMap *dead_bit_map) :
|
|
1817 |
_collector(collector),
|
|
1818 |
_sp(sp),
|
|
1819 |
_live_bit_map(live_bit_map),
|
|
1820 |
_dead_bit_map(dead_bit_map) {}
|
|
1821 |
size_t do_blk(HeapWord* addr);
|
|
1822 |
};
|