--- a/src/hotspot/share/gc/cms/compactibleFreeListSpace.hpp Fri Nov 08 14:54:17 2019 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,758 +0,0 @@
-/*
- * Copyright (c) 2001, 2019, 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
- * questions.
- *
- */
-
-#ifndef SHARE_GC_CMS_COMPACTIBLEFREELISTSPACE_HPP
-#define SHARE_GC_CMS_COMPACTIBLEFREELISTSPACE_HPP
-
-#include "gc/cms/adaptiveFreeList.hpp"
-#include "gc/cms/promotionInfo.hpp"
-#include "gc/shared/blockOffsetTable.hpp"
-#include "gc/shared/cardTable.hpp"
-#include "gc/shared/space.hpp"
-#include "logging/log.hpp"
-#include "memory/binaryTreeDictionary.hpp"
-#include "memory/freeList.hpp"
-
-// Classes in support of keeping track of promotions into a non-Contiguous
-// space, in this case a CompactibleFreeListSpace.
-
-// Forward declarations
-class CMSCollector;
-class CompactibleFreeListSpace;
-class ConcurrentMarkSweepGeneration;
-class BlkClosure;
-class BlkClosureCareful;
-class FreeChunk;
-class UpwardsObjectClosure;
-class ObjectClosureCareful;
-class Klass;
-
-class AFLBinaryTreeDictionary : public BinaryTreeDictionary<FreeChunk, AdaptiveFreeList<FreeChunk> > {
- public:
- AFLBinaryTreeDictionary(MemRegion mr)
- : BinaryTreeDictionary<FreeChunk, AdaptiveFreeList<FreeChunk> >(mr) {}
-
- // Find the list with size "size" in the binary tree and update
- // the statistics in the list according to "split" (chunk was
- // split or coalesce) and "birth" (chunk was added or removed).
- void dict_census_update(size_t size, bool split, bool birth);
- // Return true if the dictionary is overpopulated (more chunks of
- // this size than desired) for size "size".
- bool coal_dict_over_populated(size_t size);
- // Methods called at the beginning of a sweep to prepare the
- // statistics for the sweep.
- void begin_sweep_dict_census(double coalSurplusPercent,
- float inter_sweep_current,
- float inter_sweep_estimate,
- float intra_sweep_estimate);
- // Methods called after the end of a sweep to modify the
- // statistics for the sweep.
- void end_sweep_dict_census(double splitSurplusPercent);
- // Accessors for statistics
- void set_tree_surplus(double splitSurplusPercent);
- void set_tree_hints(void);
- // Reset statistics for all the lists in the tree.
- void clear_tree_census(void);
- // Print the statistics for all the lists in the tree. Also may
- // print out summaries.
- void print_dict_census(outputStream* st) const;
-};
-
-class LinearAllocBlock {
- public:
- LinearAllocBlock() : _ptr(0), _word_size(0), _refillSize(0),
- _allocation_size_limit(0) {}
- void set(HeapWord* ptr, size_t word_size, size_t refill_size,
- size_t allocation_size_limit) {
- _ptr = ptr;
- _word_size = word_size;
- _refillSize = refill_size;
- _allocation_size_limit = allocation_size_limit;
- }
- HeapWord* _ptr;
- size_t _word_size;
- size_t _refillSize;
- size_t _allocation_size_limit; // Largest size that will be allocated
-
- void print_on(outputStream* st) const;
-};
-
-// Concrete subclass of CompactibleSpace that implements
-// a free list space, such as used in the concurrent mark sweep
-// generation.
-
-class CompactibleFreeListSpace: public CompactibleSpace {
- friend class VMStructs;
- friend class ConcurrentMarkSweepGeneration;
- friend class CMSCollector;
- // Local alloc buffer for promotion into this space.
- friend class CompactibleFreeListSpaceLAB;
- // Allow scan_and_* functions to call (private) overrides of the auxiliary functions on this class
- template <typename SpaceType>
- friend void CompactibleSpace::scan_and_adjust_pointers(SpaceType* space);
- template <typename SpaceType>
- friend void CompactibleSpace::scan_and_compact(SpaceType* space);
- template <typename SpaceType>
- friend void CompactibleSpace::verify_up_to_first_dead(SpaceType* space);
- template <typename SpaceType>
- friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
-
- // "Size" of chunks of work (executed during parallel remark phases
- // of CMS collection); this probably belongs in CMSCollector, although
- // it's cached here because it's used in
- // initialize_sequential_subtasks_for_rescan() which modifies
- // par_seq_tasks which also lives in Space. XXX
- const size_t _rescan_task_size;
- const size_t _marking_task_size;
-
- // Yet another sequential tasks done structure. This supports
- // CMS GC, where we have threads dynamically
- // claiming sub-tasks from a larger parallel task.
- SequentialSubTasksDone _conc_par_seq_tasks;
-
- BlockOffsetArrayNonContigSpace _bt;
-
- CMSCollector* _collector;
- ConcurrentMarkSweepGeneration* _old_gen;
-
- // Data structures for free blocks (used during allocation/sweeping)
-
- // Allocation is done linearly from two different blocks depending on
- // whether the request is small or large, in an effort to reduce
- // fragmentation. We assume that any locking for allocation is done
- // by the containing generation. Thus, none of the methods in this
- // space are re-entrant.
- enum SomeConstants {
- SmallForLinearAlloc = 16, // size < this then use _sLAB
- SmallForDictionary = 257, // size < this then use _indexedFreeList
- IndexSetSize = SmallForDictionary // keep this odd-sized
- };
- static size_t IndexSetStart;
- static size_t IndexSetStride;
- static size_t _min_chunk_size_in_bytes;
-
- private:
- enum FitStrategyOptions {
- FreeBlockStrategyNone = 0,
- FreeBlockBestFitFirst
- };
-
- PromotionInfo _promoInfo;
-
- // Helps to impose a global total order on freelistLock ranks;
- // assumes that CFLSpace's are allocated in global total order
- static int _lockRank;
-
- // A lock protecting the free lists and free blocks;
- // mutable because of ubiquity of locking even for otherwise const methods
- mutable Mutex _freelistLock;
-
- // Locking verifier convenience function
- void assert_locked() const PRODUCT_RETURN;
- void assert_locked(const Mutex* lock) const PRODUCT_RETURN;
-
- // Linear allocation blocks
- LinearAllocBlock _smallLinearAllocBlock;
-
- AFLBinaryTreeDictionary* _dictionary; // Pointer to dictionary for large size blocks
-
- // Indexed array for small size blocks
- AdaptiveFreeList<FreeChunk> _indexedFreeList[IndexSetSize];
-
- // Allocation strategy
- bool _fitStrategy; // Use best fit strategy
-
- // This is an address close to the largest free chunk in the heap.
- // It is currently assumed to be at the end of the heap. Free
- // chunks with addresses greater than nearLargestChunk are coalesced
- // in an effort to maintain a large chunk at the end of the heap.
- HeapWord* _nearLargestChunk;
-
- // Used to keep track of limit of sweep for the space
- HeapWord* _sweep_limit;
-
- // Stable value of used().
- size_t _used_stable;
-
- // Used to make the young collector update the mod union table
- MemRegionClosure* _preconsumptionDirtyCardClosure;
-
- // Support for compacting cms
- HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
- HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top);
-
- // Initialization helpers.
- void initializeIndexedFreeListArray();
-
- // Extra stuff to manage promotion parallelism.
-
- // A lock protecting the dictionary during par promotion allocation.
- mutable Mutex _parDictionaryAllocLock;
- Mutex* parDictionaryAllocLock() const { return &_parDictionaryAllocLock; }
-
- // Locks protecting the exact lists during par promotion allocation.
- Mutex* _indexedFreeListParLocks[IndexSetSize];
-
- // Attempt to obtain up to "n" blocks of the size "word_sz" (which is
- // required to be smaller than "IndexSetSize".) If successful,
- // adds them to "fl", which is required to be an empty free list.
- // If the count of "fl" is negative, it's absolute value indicates a
- // number of free chunks that had been previously "borrowed" from global
- // list of size "word_sz", and must now be decremented.
- void par_get_chunk_of_blocks(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl);
-
- // Used by par_get_chunk_of_blocks() for the chunks from the
- // indexed_free_lists.
- bool par_get_chunk_of_blocks_IFL(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl);
-
- // Used by par_get_chunk_of_blocks_dictionary() to get a chunk
- // evenly splittable into "n" "word_sz" chunks. Returns that
- // evenly splittable chunk. May split a larger chunk to get the
- // evenly splittable chunk.
- FreeChunk* get_n_way_chunk_to_split(size_t word_sz, size_t n);
-
- // Used by par_get_chunk_of_blocks() for the chunks from the
- // dictionary.
- void par_get_chunk_of_blocks_dictionary(size_t word_sz, size_t n, AdaptiveFreeList<FreeChunk>* fl);
-
- // Allocation helper functions
- // Allocate using a strategy that takes from the indexed free lists
- // first. This allocation strategy assumes a companion sweeping
- // strategy that attempts to keep the needed number of chunks in each
- // indexed free lists.
- HeapWord* allocate_adaptive_freelists(size_t size);
-
- // Gets a chunk from the linear allocation block (LinAB). If there
- // is not enough space in the LinAB, refills it.
- HeapWord* getChunkFromLinearAllocBlock(LinearAllocBlock* blk, size_t size);
- HeapWord* getChunkFromSmallLinearAllocBlock(size_t size);
- // Get a chunk from the space remaining in the linear allocation block. Do
- // not attempt to refill if the space is not available, return NULL. Do the
- // repairs on the linear allocation block as appropriate.
- HeapWord* getChunkFromLinearAllocBlockRemainder(LinearAllocBlock* blk, size_t size);
- inline HeapWord* getChunkFromSmallLinearAllocBlockRemainder(size_t size);
-
- // Helper function for getChunkFromIndexedFreeList.
- // Replenish the indexed free list for this "size". Do not take from an
- // underpopulated size.
- FreeChunk* getChunkFromIndexedFreeListHelper(size_t size, bool replenish = true);
-
- // Get a chunk from the indexed free list. If the indexed free list
- // does not have a free chunk, try to replenish the indexed free list
- // then get the free chunk from the replenished indexed free list.
- inline FreeChunk* getChunkFromIndexedFreeList(size_t size);
-
- // The returned chunk may be larger than requested (or null).
- FreeChunk* getChunkFromDictionary(size_t size);
- // The returned chunk is the exact size requested (or null).
- FreeChunk* getChunkFromDictionaryExact(size_t size);
-
- // Find a chunk in the indexed free list that is the best
- // fit for size "numWords".
- FreeChunk* bestFitSmall(size_t numWords);
- // For free list "fl" of chunks of size > numWords,
- // remove a chunk, split off a chunk of size numWords
- // and return it. The split off remainder is returned to
- // the free lists. The old name for getFromListGreater
- // was lookInListGreater.
- FreeChunk* getFromListGreater(AdaptiveFreeList<FreeChunk>* fl, size_t numWords);
- // Get a chunk in the indexed free list or dictionary,
- // by considering a larger chunk and splitting it.
- FreeChunk* getChunkFromGreater(size_t numWords);
- // Verify that the given chunk is in the indexed free lists.
- bool verifyChunkInIndexedFreeLists(FreeChunk* fc) const;
- // Remove the specified chunk from the indexed free lists.
- void removeChunkFromIndexedFreeList(FreeChunk* fc);
- // Remove the specified chunk from the dictionary.
- void removeChunkFromDictionary(FreeChunk* fc);
- // Split a free chunk into a smaller free chunk of size "new_size".
- // Return the smaller free chunk and return the remainder to the
- // free lists.
- FreeChunk* splitChunkAndReturnRemainder(FreeChunk* chunk, size_t new_size);
- // Add a chunk to the free lists.
- void addChunkToFreeLists(HeapWord* chunk, size_t size);
- // Add a chunk to the free lists, preferring to suffix it
- // to the last free chunk at end of space if possible, and
- // updating the block census stats as well as block offset table.
- // Take any locks as appropriate if we are multithreaded.
- void addChunkToFreeListsAtEndRecordingStats(HeapWord* chunk, size_t size);
- // Add a free chunk to the indexed free lists.
- void returnChunkToFreeList(FreeChunk* chunk);
- // Add a free chunk to the dictionary.
- void returnChunkToDictionary(FreeChunk* chunk);
-
- // Functions for maintaining the linear allocation buffers (LinAB).
- // Repairing a linear allocation block refers to operations
- // performed on the remainder of a LinAB after an allocation
- // has been made from it.
- void repairLinearAllocationBlocks();
- void repairLinearAllocBlock(LinearAllocBlock* blk);
- void refillLinearAllocBlock(LinearAllocBlock* blk);
- void refillLinearAllocBlockIfNeeded(LinearAllocBlock* blk);
- void refillLinearAllocBlocksIfNeeded();
-
- void verify_objects_initialized() const;
-
- // Statistics reporting helper functions
- void reportFreeListStatistics(const char* title) const;
- void reportIndexedFreeListStatistics(outputStream* st) const;
- size_t maxChunkSizeInIndexedFreeLists() const;
- size_t numFreeBlocksInIndexedFreeLists() const;
- // Accessor
- HeapWord* unallocated_block() const {
- if (BlockOffsetArrayUseUnallocatedBlock) {
- HeapWord* ub = _bt.unallocated_block();
- assert(ub >= bottom() &&
- ub <= end(), "space invariant");
- return ub;
- } else {
- return end();
- }
- }
- void freed(HeapWord* start, size_t size) {
- _bt.freed(start, size);
- }
-
- // Auxiliary functions for scan_and_{forward,adjust_pointers,compact} support.
- // See comments for CompactibleSpace for more information.
- inline HeapWord* scan_limit() const {
- return end();
- }
-
- inline bool scanned_block_is_obj(const HeapWord* addr) const {
- return CompactibleFreeListSpace::block_is_obj(addr); // Avoid virtual call
- }
-
- inline size_t scanned_block_size(const HeapWord* addr) const {
- return CompactibleFreeListSpace::block_size(addr); // Avoid virtual call
- }
-
- inline size_t adjust_obj_size(size_t size) const {
- return adjustObjectSize(size);
- }
-
- inline size_t obj_size(const HeapWord* addr) const;
-
- protected:
- // Reset the indexed free list to its initial empty condition.
- void resetIndexedFreeListArray();
- // Reset to an initial state with a single free block described
- // by the MemRegion parameter.
- void reset(MemRegion mr);
- // Return the total number of words in the indexed free lists.
- size_t totalSizeInIndexedFreeLists() const;
-
- public:
- // Constructor
- CompactibleFreeListSpace(BlockOffsetSharedArray* bs, MemRegion mr);
- // Accessors
- bool bestFitFirst() { return _fitStrategy == FreeBlockBestFitFirst; }
- AFLBinaryTreeDictionary* dictionary() const { return _dictionary; }
- HeapWord* nearLargestChunk() const { return _nearLargestChunk; }
- void set_nearLargestChunk(HeapWord* v) { _nearLargestChunk = v; }
-
- // Set CMS global values.
- static void set_cms_values();
-
- // Return the free chunk at the end of the space. If no such
- // chunk exists, return NULL.
- FreeChunk* find_chunk_at_end();
-
- void set_collector(CMSCollector* collector) { _collector = collector; }
-
- // Support for parallelization of rescan and marking.
- const size_t rescan_task_size() const { return _rescan_task_size; }
- const size_t marking_task_size() const { return _marking_task_size; }
- // Return ergonomic max size for CMSRescanMultiple and CMSConcMarkMultiple.
- const size_t max_flag_size_for_task_size() const;
- SequentialSubTasksDone* conc_par_seq_tasks() {return &_conc_par_seq_tasks; }
- void initialize_sequential_subtasks_for_rescan(int n_threads);
- void initialize_sequential_subtasks_for_marking(int n_threads,
- HeapWord* low = NULL);
-
- virtual MemRegionClosure* preconsumptionDirtyCardClosure() const {
- return _preconsumptionDirtyCardClosure;
- }
-
- void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) {
- _preconsumptionDirtyCardClosure = cl;
- }
-
- // Space enquiries
- size_t used() const;
- size_t free() const;
- size_t max_alloc_in_words() const;
- // XXX: should have a less conservative used_region() than that of
- // Space; we could consider keeping track of highest allocated
- // address and correcting that at each sweep, as the sweeper
- // goes through the entire allocated part of the generation. We
- // could also use that information to keep the sweeper from
- // sweeping more than is necessary. The allocator and sweeper will
- // of course need to synchronize on this, since the sweeper will
- // try to bump down the address and the allocator will try to bump it up.
- // For now, however, we'll just use the default used_region()
- // which overestimates the region by returning the entire
- // committed region (this is safe, but inefficient).
-
- // Returns monotonically increasing stable used space bytes for CMS.
- // This is required for jstat and other memory monitoring tools
- // that might otherwise see inconsistent used space values during a garbage
- // collection, promotion or allocation into compactibleFreeListSpace.
- // The value returned by this function might be smaller than the
- // actual value.
- size_t used_stable() const;
- // Recalculate and cache the current stable used() value. Only to be called
- // in places where we can be sure that the result is stable.
- void recalculate_used_stable();
-
- // Returns a subregion of the space containing all the objects in
- // the space.
- MemRegion used_region() const {
- return MemRegion(bottom(),
- BlockOffsetArrayUseUnallocatedBlock ?
- unallocated_block() : end());
- }
-
- virtual bool is_free_block(const HeapWord* p) const;
-
- // Resizing support
- void set_end(HeapWord* value); // override
-
- // Never mangle CompactibleFreeListSpace
- void mangle_unused_area() {}
- void mangle_unused_area_complete() {}
-
- // Mutual exclusion support
- Mutex* freelistLock() const { return &_freelistLock; }
-
- // Iteration support
- void oop_iterate(OopIterateClosure* cl);
-
- void object_iterate(ObjectClosure* blk);
- // Apply the closure to each object in the space whose references
- // point to objects in the heap. The usage of CompactibleFreeListSpace
- // by the ConcurrentMarkSweepGeneration for concurrent GC's allows
- // objects in the space with references to objects that are no longer
- // valid. For example, an object may reference another object
- // that has already been sweep up (collected). This method uses
- // obj_is_alive() to determine whether it is safe to iterate of
- // an object.
- void safe_object_iterate(ObjectClosure* blk);
-
- // Iterate over all objects that intersect with mr, calling "cl->do_object"
- // on each. There is an exception to this: if this closure has already
- // been invoked on an object, it may skip such objects in some cases. This is
- // Most likely to happen in an "upwards" (ascending address) iteration of
- // MemRegions.
- void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
-
- // Requires that "mr" be entirely within the space.
- // Apply "cl->do_object" to all objects that intersect with "mr".
- // If the iteration encounters an unparseable portion of the region,
- // terminate the iteration and return the address of the start of the
- // subregion that isn't done. Return of "NULL" indicates that the
- // iteration completed.
- HeapWord* object_iterate_careful_m(MemRegion mr,
- ObjectClosureCareful* cl);
-
- // Override: provides a DCTO_CL specific to this kind of space.
- DirtyCardToOopClosure* new_dcto_cl(OopIterateClosure* cl,
- CardTable::PrecisionStyle precision,
- HeapWord* boundary,
- bool parallel);
-
- void blk_iterate(BlkClosure* cl);
- void blk_iterate_careful(BlkClosureCareful* cl);
- HeapWord* block_start_const(const void* p) const;
- HeapWord* block_start_careful(const void* p) const;
- size_t block_size(const HeapWord* p) const;
- size_t block_size_no_stall(HeapWord* p, const CMSCollector* c) const;
- bool block_is_obj(const HeapWord* p) const;
- bool obj_is_alive(const HeapWord* p) const;
- size_t block_size_nopar(const HeapWord* p) const;
- bool block_is_obj_nopar(const HeapWord* p) const;
-
- // Iteration support for promotion
- void save_marks();
- bool no_allocs_since_save_marks();
-
- // Iteration support for sweeping
- void save_sweep_limit() {
- _sweep_limit = BlockOffsetArrayUseUnallocatedBlock ?
- unallocated_block() : end();
- log_develop_trace(gc, sweep)(">>>>> Saving sweep limit " PTR_FORMAT
- " for space [" PTR_FORMAT "," PTR_FORMAT ") <<<<<<",
- p2i(_sweep_limit), p2i(bottom()), p2i(end()));
- }
- NOT_PRODUCT(
- void clear_sweep_limit() { _sweep_limit = NULL; }
- )
- HeapWord* sweep_limit() { return _sweep_limit; }
-
- // Apply "blk->do_oop" to the addresses of all reference fields in objects
- // promoted into this generation since the most recent save_marks() call.
- // Fields in objects allocated by applications of the closure
- // *are* included in the iteration. Thus, when the iteration completes
- // there should be no further such objects remaining.
- template <typename OopClosureType>
- void oop_since_save_marks_iterate(OopClosureType* blk);
-
- // Allocation support
- HeapWord* allocate(size_t size);
- HeapWord* par_allocate(size_t size);
-
- oop promote(oop obj, size_t obj_size);
- void gc_prologue();
- void gc_epilogue();
-
- // This call is used by a containing CMS generation / collector
- // to inform the CFLS space that a sweep has been completed
- // and that the space can do any related house-keeping functions.
- void sweep_completed();
-
- // For an object in this space, the mark-word's two
- // LSB's having the value [11] indicates that it has been
- // promoted since the most recent call to save_marks() on
- // this generation and has not subsequently been iterated
- // over (using oop_since_save_marks_iterate() above).
- // This property holds only for single-threaded collections,
- // and is typically used for Cheney scans; for MT scavenges,
- // the property holds for all objects promoted during that
- // scavenge for the duration of the scavenge and is used
- // by card-scanning to avoid scanning objects (being) promoted
- // during that scavenge.
- bool obj_allocated_since_save_marks(const oop obj) const {
- assert(is_in_reserved(obj), "Wrong space?");
- return ((PromotedObject*)obj)->hasPromotedMark();
- }
-
- // A worst-case estimate of the space required (in HeapWords) to expand the
- // heap when promoting an obj of size obj_size.
- size_t expansionSpaceRequired(size_t obj_size) const;
-
- FreeChunk* allocateScratch(size_t size);
-
- // Returns true if either the small or large linear allocation buffer is empty.
- bool linearAllocationWouldFail() const;
-
- // Adjust the chunk for the minimum size. This version is called in
- // most cases in CompactibleFreeListSpace methods.
- inline static size_t adjustObjectSize(size_t size) {
- return align_object_size(MAX2(size, (size_t)MinChunkSize));
- }
- // This is a virtual version of adjustObjectSize() that is called
- // only occasionally when the compaction space changes and the type
- // of the new compaction space is is only known to be CompactibleSpace.
- size_t adjust_object_size_v(size_t size) const {
- return adjustObjectSize(size);
- }
- // Minimum size of a free block.
- virtual size_t minimum_free_block_size() const { return MinChunkSize; }
- void removeFreeChunkFromFreeLists(FreeChunk* chunk);
- void addChunkAndRepairOffsetTable(HeapWord* chunk, size_t size,
- bool coalesced);
-
- // Support for compaction.
- void prepare_for_compaction(CompactPoint* cp);
- void adjust_pointers();
- void compact();
- // Reset the space to reflect the fact that a compaction of the
- // space has been done.
- virtual void reset_after_compaction();
-
- // Debugging support.
- void print() const;
- void print_on(outputStream* st) const;
- void prepare_for_verify();
- void verify() const;
- void verifyFreeLists() const PRODUCT_RETURN;
- void verifyIndexedFreeLists() const;
- void verifyIndexedFreeList(size_t size) const;
- // Verify that the given chunk is in the free lists:
- // i.e. either the binary tree dictionary, the indexed free lists
- // or the linear allocation block.
- bool verify_chunk_in_free_list(FreeChunk* fc) const;
- // Verify that the given chunk is the linear allocation block.
- bool verify_chunk_is_linear_alloc_block(FreeChunk* fc) const;
- // Do some basic checks on the the free lists.
- void check_free_list_consistency() const PRODUCT_RETURN;
-
- // Printing support
- void dump_at_safepoint_with_locks(CMSCollector* c, outputStream* st);
- void print_indexed_free_lists(outputStream* st) const;
- void print_dictionary_free_lists(outputStream* st) const;
- void print_promo_info_blocks(outputStream* st) const;
-
- NOT_PRODUCT (
- void initializeIndexedFreeListArrayReturnedBytes();
- size_t sumIndexedFreeListArrayReturnedBytes();
- // Return the total number of chunks in the indexed free lists.
- size_t totalCountInIndexedFreeLists() const;
- // Return the total number of chunks in the space.
- size_t totalCount();
- )
-
- // The census consists of counts of the quantities such as
- // the current count of the free chunks, number of chunks
- // created as a result of the split of a larger chunk or
- // coalescing of smaller chucks, etc. The counts in the
- // census is used to make decisions on splitting and
- // coalescing of chunks during the sweep of garbage.
-
- // Print the statistics for the free lists.
- void printFLCensus(size_t sweep_count) const;
-
- // Statistics functions
- // Initialize census for lists before the sweep.
- void beginSweepFLCensus(float inter_sweep_current,
- float inter_sweep_estimate,
- float intra_sweep_estimate);
- // Set the surplus for each of the free lists.
- void setFLSurplus();
- // Set the hint for each of the free lists.
- void setFLHints();
- // Clear the census for each of the free lists.
- void clearFLCensus();
- // Perform functions for the census after the end of the sweep.
- void endSweepFLCensus(size_t sweep_count);
- // Return true if the count of free chunks is greater
- // than the desired number of free chunks.
- bool coalOverPopulated(size_t size);
-
-// Record (for each size):
-//
-// split-births = #chunks added due to splits in (prev-sweep-end,
-// this-sweep-start)
-// split-deaths = #chunks removed for splits in (prev-sweep-end,
-// this-sweep-start)
-// num-curr = #chunks at start of this sweep
-// num-prev = #chunks at end of previous sweep
-//
-// The above are quantities that are measured. Now define:
-//
-// num-desired := num-prev + split-births - split-deaths - num-curr
-//
-// Roughly, num-prev + split-births is the supply,
-// split-deaths is demand due to other sizes
-// and num-curr is what we have left.
-//
-// Thus, num-desired is roughly speaking the "legitimate demand"
-// for blocks of this size and what we are striving to reach at the
-// end of the current sweep.
-//
-// For a given list, let num-len be its current population.
-// Define, for a free list of a given size:
-//
-// coal-overpopulated := num-len >= num-desired * coal-surplus
-// (coal-surplus is set to 1.05, i.e. we allow a little slop when
-// coalescing -- we do not coalesce unless we think that the current
-// supply has exceeded the estimated demand by more than 5%).
-//
-// For the set of sizes in the binary tree, which is neither dense nor
-// closed, it may be the case that for a particular size we have never
-// had, or do not now have, or did not have at the previous sweep,
-// chunks of that size. We need to extend the definition of
-// coal-overpopulated to such sizes as well:
-//
-// For a chunk in/not in the binary tree, extend coal-overpopulated
-// defined above to include all sizes as follows:
-//
-// . a size that is non-existent is coal-overpopulated
-// . a size that has a num-desired <= 0 as defined above is
-// coal-overpopulated.
-//
-// Also define, for a chunk heap-offset C and mountain heap-offset M:
-//
-// close-to-mountain := C >= 0.99 * M
-//
-// Now, the coalescing strategy is:
-//
-// Coalesce left-hand chunk with right-hand chunk if and
-// only if:
-//
-// EITHER
-// . left-hand chunk is of a size that is coal-overpopulated
-// OR
-// . right-hand chunk is close-to-mountain
- void smallCoalBirth(size_t size);
- void smallCoalDeath(size_t size);
- void coalBirth(size_t size);
- void coalDeath(size_t size);
- void smallSplitBirth(size_t size);
- void smallSplitDeath(size_t size);
- void split_birth(size_t size);
- void splitDeath(size_t size);
- void split(size_t from, size_t to1);
-
- double flsFrag() const;
-};
-
-// A parallel-GC-thread-local allocation buffer for allocation into a
-// CompactibleFreeListSpace.
-class CompactibleFreeListSpaceLAB : public CHeapObj<mtGC> {
- // The space that this buffer allocates into.
- CompactibleFreeListSpace* _cfls;
-
- // Our local free lists.
- AdaptiveFreeList<FreeChunk> _indexedFreeList[CompactibleFreeListSpace::IndexSetSize];
-
- // Initialized from a command-line arg.
-
- // Allocation statistics in support of dynamic adjustment of
- // #blocks to claim per get_from_global_pool() call below.
- static AdaptiveWeightedAverage
- _blocks_to_claim [CompactibleFreeListSpace::IndexSetSize];
- static size_t _global_num_blocks [CompactibleFreeListSpace::IndexSetSize];
- static uint _global_num_workers[CompactibleFreeListSpace::IndexSetSize];
- size_t _num_blocks [CompactibleFreeListSpace::IndexSetSize];
-
- // Internal work method
- void get_from_global_pool(size_t word_sz, AdaptiveFreeList<FreeChunk>* fl);
-
-public:
- static const int _default_dynamic_old_plab_size = 16;
- static const int _default_static_old_plab_size = 50;
-
- CompactibleFreeListSpaceLAB(CompactibleFreeListSpace* cfls);
-
- // Allocate and return a block of the given size, or else return NULL.
- HeapWord* alloc(size_t word_sz);
-
- // Return any unused portions of the buffer to the global pool.
- void retire(int tid);
-
- // Dynamic OldPLABSize sizing
- static void compute_desired_plab_size();
- // When the settings are modified from default static initialization
- static void modify_initialization(size_t n, unsigned wt);
-};
-
-size_t PromotionInfo::refillSize() const {
- const size_t CMSSpoolBlockSize = 256;
- const size_t sz = heap_word_size(sizeof(SpoolBlock) + sizeof(markWord)
- * CMSSpoolBlockSize);
- return CompactibleFreeListSpace::adjustObjectSize(sz);
-}
-
-#endif // SHARE_GC_CMS_COMPACTIBLEFREELISTSPACE_HPP