--- old/src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp 2015-05-13 13:56:30.260263460 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,490 +0,0 @@ -/* - * Copyright (c) 2001, 2014, 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_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP -#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP - -#include "gc_implementation/g1/g1CodeCacheRemSet.hpp" -#include "gc_implementation/g1/sparsePRT.hpp" - -// Remembered set for a heap region. Represent a set of "cards" that -// contain pointers into the owner heap region. Cards are defined somewhat -// abstractly, in terms of what the "BlockOffsetTable" in use can parse. - -class G1CollectedHeap; -class G1BlockOffsetSharedArray; -class HeapRegion; -class HeapRegionRemSetIterator; -class PerRegionTable; -class SparsePRT; -class nmethod; - -// Essentially a wrapper around SparsePRTCleanupTask. See -// sparsePRT.hpp for more details. -class HRRSCleanupTask : public SparsePRTCleanupTask { -}; - -// The FromCardCache remembers the most recently processed card on the heap on -// a per-region and per-thread basis. -class FromCardCache : public AllStatic { - private: - // Array of card indices. Indexed by thread X and heap region to minimize - // thread contention. - static int** _cache; - static uint _max_regions; - static size_t _static_mem_size; - - public: - enum { - InvalidCard = -1 // Card value of an invalid card, i.e. a card index not otherwise used. - }; - - static void clear(uint region_idx); - - // Returns true if the given card is in the cache at the given location, or - // replaces the card at that location and returns false. - static bool contains_or_replace(uint worker_id, uint region_idx, int card) { - int card_in_cache = at(worker_id, region_idx); - if (card_in_cache == card) { - return true; - } else { - set(worker_id, region_idx, card); - return false; - } - } - - static int at(uint worker_id, uint region_idx) { - return _cache[worker_id][region_idx]; - } - - static void set(uint worker_id, uint region_idx, int val) { - _cache[worker_id][region_idx] = val; - } - - static void initialize(uint n_par_rs, uint max_num_regions); - - static void invalidate(uint start_idx, size_t num_regions); - - static void print(outputStream* out = gclog_or_tty) PRODUCT_RETURN; - - static size_t static_mem_size() { - return _static_mem_size; - } -}; - -// The "_coarse_map" is a bitmap with one bit for each region, where set -// bits indicate that the corresponding region may contain some pointer -// into the owning region. - -// The "_fine_grain_entries" array is an open hash table of PerRegionTables -// (PRTs), indicating regions for which we're keeping the RS as a set of -// cards. The strategy is to cap the size of the fine-grain table, -// deleting an entry and setting the corresponding coarse-grained bit when -// we would overflow this cap. - -// We use a mixture of locking and lock-free techniques here. We allow -// threads to locate PRTs without locking, but threads attempting to alter -// a bucket list obtain a lock. This means that any failing attempt to -// find a PRT must be retried with the lock. It might seem dangerous that -// a read can find a PRT that is concurrently deleted. This is all right, -// because: -// -// 1) We only actually free PRT's at safe points (though we reuse them at -// other times). -// 2) We find PRT's in an attempt to add entries. If a PRT is deleted, -// it's _coarse_map bit is set, so the that we were attempting to add -// is represented. If a deleted PRT is re-used, a thread adding a bit, -// thinking the PRT is for a different region, does no harm. - -class OtherRegionsTable VALUE_OBJ_CLASS_SPEC { - friend class HeapRegionRemSetIterator; - - G1CollectedHeap* _g1h; - Mutex* _m; - HeapRegion* _hr; - - // These are protected by "_m". - BitMap _coarse_map; - size_t _n_coarse_entries; - static jint _n_coarsenings; - - PerRegionTable** _fine_grain_regions; - size_t _n_fine_entries; - - // The fine grain remembered sets are doubly linked together using - // their 'next' and 'prev' fields. - // This allows fast bulk freeing of all the fine grain remembered - // set entries, and fast finding of all of them without iterating - // over the _fine_grain_regions table. - PerRegionTable * _first_all_fine_prts; - PerRegionTable * _last_all_fine_prts; - - // Used to sample a subset of the fine grain PRTs to determine which - // PRT to evict and coarsen. - size_t _fine_eviction_start; - static size_t _fine_eviction_stride; - static size_t _fine_eviction_sample_size; - - SparsePRT _sparse_table; - - // These are static after init. - static size_t _max_fine_entries; - static size_t _mod_max_fine_entries_mask; - - // Requires "prt" to be the first element of the bucket list appropriate - // for "hr". If this list contains an entry for "hr", return it, - // otherwise return "NULL". - PerRegionTable* find_region_table(size_t ind, HeapRegion* hr) const; - - // Find, delete, and return a candidate PerRegionTable, if any exists, - // adding the deleted region to the coarse bitmap. Requires the caller - // to hold _m, and the fine-grain table to be full. - PerRegionTable* delete_region_table(); - - // link/add the given fine grain remembered set into the "all" list - void link_to_all(PerRegionTable * prt); - // unlink/remove the given fine grain remembered set into the "all" list - void unlink_from_all(PerRegionTable * prt); - - bool contains_reference_locked(OopOrNarrowOopStar from) const; - - // Clear the from_card_cache entries for this region. - void clear_fcc(); -public: - // Create a new remembered set for the given heap region. The given mutex should - // be used to ensure consistency. - OtherRegionsTable(HeapRegion* hr, Mutex* m); - - // For now. Could "expand" some tables in the future, so that this made - // sense. - void add_reference(OopOrNarrowOopStar from, uint tid); - - // Returns whether the remembered set contains the given reference. - bool contains_reference(OopOrNarrowOopStar from) const; - - // Returns whether this remembered set (and all sub-sets) have an occupancy - // that is less or equal than the given occupancy. - bool occupancy_less_or_equal_than(size_t limit) const; - - // Removes any entries shown by the given bitmaps to contain only dead - // objects. Not thread safe. - // Set bits in the bitmaps indicate that the given region or card is live. - void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); - - // Returns whether this remembered set (and all sub-sets) does not contain any entry. - bool is_empty() const; - - // Returns the number of cards contained in this remembered set. - size_t occupied() const; - size_t occ_fine() const; - size_t occ_coarse() const; - size_t occ_sparse() const; - - static jint n_coarsenings() { return _n_coarsenings; } - - // Returns size of the actual remembered set containers in bytes. - size_t mem_size() const; - // Returns the size of static data in bytes. - static size_t static_mem_size(); - // Returns the size of the free list content in bytes. - static size_t fl_mem_size(); - - // Clear the entire contents of this remembered set. - void clear(); - - void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task); -}; - -class HeapRegionRemSet : public CHeapObj { - friend class VMStructs; - friend class HeapRegionRemSetIterator; - -public: - enum Event { - Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd - }; - -private: - G1BlockOffsetSharedArray* _bosa; - - // A set of code blobs (nmethods) whose code contains pointers into - // the region that owns this RSet. - G1CodeRootSet _code_roots; - - Mutex _m; - - OtherRegionsTable _other_regions; - - enum ParIterState { Unclaimed, Claimed, Complete }; - volatile ParIterState _iter_state; - volatile size_t _iter_claimed; - - // Unused unless G1RecordHRRSOops is true. - - static const int MaxRecorded = 1000000; - static OopOrNarrowOopStar* _recorded_oops; - static HeapWord** _recorded_cards; - static HeapRegion** _recorded_regions; - static int _n_recorded; - - static const int MaxRecordedEvents = 1000; - static Event* _recorded_events; - static int* _recorded_event_index; - static int _n_recorded_events; - - static void print_event(outputStream* str, Event evnt); - -public: - HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, HeapRegion* hr); - - static uint num_par_rem_sets(); - static void setup_remset_size(); - - bool is_empty() const { - return (strong_code_roots_list_length() == 0) && _other_regions.is_empty(); - } - - bool occupancy_less_or_equal_than(size_t occ) const { - return (strong_code_roots_list_length() == 0) && _other_regions.occupancy_less_or_equal_than(occ); - } - - size_t occupied() { - MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); - return occupied_locked(); - } - size_t occupied_locked() { - return _other_regions.occupied(); - } - size_t occ_fine() const { - return _other_regions.occ_fine(); - } - size_t occ_coarse() const { - return _other_regions.occ_coarse(); - } - size_t occ_sparse() const { - return _other_regions.occ_sparse(); - } - - static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); } - - // Used in the sequential case. - void add_reference(OopOrNarrowOopStar from) { - _other_regions.add_reference(from, 0); - } - - // Used in the parallel case. - void add_reference(OopOrNarrowOopStar from, uint tid) { - _other_regions.add_reference(from, tid); - } - - // Removes any entries in the remembered set shown by the given bitmaps to - // contain only dead objects. Not thread safe. - // One bits in the bitmaps indicate that the given region or card is live. - void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); - - // The region is being reclaimed; clear its remset, and any mention of - // entries for this region in other remsets. - void clear(); - void clear_locked(); - - // Attempt to claim the region. Returns true iff this call caused an - // atomic transition from Unclaimed to Claimed. - bool claim_iter(); - // Sets the iteration state to "complete". - void set_iter_complete(); - // Returns "true" iff the region's iteration is complete. - bool iter_is_complete(); - - // Support for claiming blocks of cards during iteration - size_t iter_claimed() const { return _iter_claimed; } - // Claim the next block of cards - size_t iter_claimed_next(size_t step) { - return Atomic::add(step, &_iter_claimed) - step; - } - - void reset_for_par_iteration(); - - bool verify_ready_for_par_iteration() { - return (_iter_state == Unclaimed) && (_iter_claimed == 0); - } - - // The actual # of bytes this hr_remset takes up. - // Note also includes the strong code root set. - size_t mem_size() { - MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); - return _other_regions.mem_size() - // This correction is necessary because the above includes the second - // part. - + (sizeof(HeapRegionRemSet) - sizeof(OtherRegionsTable)) - + strong_code_roots_mem_size(); - } - - // Returns the memory occupancy of all static data structures associated - // with remembered sets. - static size_t static_mem_size() { - return OtherRegionsTable::static_mem_size() + G1CodeRootSet::static_mem_size(); - } - - // Returns the memory occupancy of all free_list data structures associated - // with remembered sets. - static size_t fl_mem_size() { - return OtherRegionsTable::fl_mem_size(); - } - - bool contains_reference(OopOrNarrowOopStar from) const { - return _other_regions.contains_reference(from); - } - - // Routines for managing the list of code roots that point into - // the heap region that owns this RSet. - void add_strong_code_root(nmethod* nm); - void add_strong_code_root_locked(nmethod* nm); - void remove_strong_code_root(nmethod* nm); - - // Applies blk->do_code_blob() to each of the entries in - // the strong code roots list - void strong_code_roots_do(CodeBlobClosure* blk) const; - - void clean_strong_code_roots(HeapRegion* hr); - - // Returns the number of elements in the strong code roots list - size_t strong_code_roots_list_length() const { - return _code_roots.length(); - } - - // Returns true if the strong code roots contains the given - // nmethod. - bool strong_code_roots_list_contains(nmethod* nm) { - return _code_roots.contains(nm); - } - - // Returns the amount of memory, in bytes, currently - // consumed by the strong code roots. - size_t strong_code_roots_mem_size(); - - void print() PRODUCT_RETURN; - - // Called during a stop-world phase to perform any deferred cleanups. - static void cleanup(); - - // Declare the heap size (in # of regions) to the HeapRegionRemSet(s). - // (Uses it to initialize from_card_cache). - static void init_heap(uint max_regions) { - FromCardCache::initialize(num_par_rem_sets(), max_regions); - } - - static void invalidate_from_card_cache(uint start_idx, size_t num_regions) { - FromCardCache::invalidate(start_idx, num_regions); - } - -#ifndef PRODUCT - static void print_from_card_cache() { - FromCardCache::print(); - } -#endif - - static void record(HeapRegion* hr, OopOrNarrowOopStar f); - static void print_recorded(); - static void record_event(Event evnt); - - // These are wrappers for the similarly-named methods on - // SparsePRT. Look at sparsePRT.hpp for more details. - static void reset_for_cleanup_tasks(); - void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task); - static void finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task); - - // Run unit tests. -#ifndef PRODUCT - static void test_prt(); - static void test(); -#endif -}; - -class HeapRegionRemSetIterator : public StackObj { - private: - // The region RSet over which we are iterating. - HeapRegionRemSet* _hrrs; - - // Local caching of HRRS fields. - const BitMap* _coarse_map; - - G1BlockOffsetSharedArray* _bosa; - G1CollectedHeap* _g1h; - - // The number of cards yielded since initialization. - size_t _n_yielded_fine; - size_t _n_yielded_coarse; - size_t _n_yielded_sparse; - - // Indicates what granularity of table that we are currently iterating over. - // We start iterating over the sparse table, progress to the fine grain - // table, and then finish with the coarse table. - enum IterState { - Sparse, - Fine, - Coarse - }; - IterState _is; - - // For both Coarse and Fine remembered set iteration this contains the - // first card number of the heap region we currently iterate over. - size_t _cur_region_card_offset; - - // Current region index for the Coarse remembered set iteration. - int _coarse_cur_region_index; - size_t _coarse_cur_region_cur_card; - - bool coarse_has_next(size_t& card_index); - - // The PRT we are currently iterating over. - PerRegionTable* _fine_cur_prt; - // Card offset within the current PRT. - size_t _cur_card_in_prt; - - // Update internal variables when switching to the given PRT. - void switch_to_prt(PerRegionTable* prt); - bool fine_has_next(); - bool fine_has_next(size_t& card_index); - - // The Sparse remembered set iterator. - SparsePRTIter _sparse_iter; - - public: - HeapRegionRemSetIterator(HeapRegionRemSet* hrrs); - - // If there remains one or more cards to be yielded, returns true and - // sets "card_index" to one of those cards (which is then considered - // yielded.) Otherwise, returns false (and leaves "card_index" - // undefined.) - bool has_next(size_t& card_index); - - size_t n_yielded_fine() { return _n_yielded_fine; } - size_t n_yielded_coarse() { return _n_yielded_coarse; } - size_t n_yielded_sparse() { return _n_yielded_sparse; } - size_t n_yielded() { - return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse(); - } -}; - -#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/g1/heapRegionRemSet.hpp 2015-05-13 13:56:29.990252256 +0200 @@ -0,0 +1,490 @@ +/* + * Copyright (c) 2001, 2015, 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_VM_GC_G1_HEAPREGIONREMSET_HPP +#define SHARE_VM_GC_G1_HEAPREGIONREMSET_HPP + +#include "gc/g1/g1CodeCacheRemSet.hpp" +#include "gc/g1/sparsePRT.hpp" + +// Remembered set for a heap region. Represent a set of "cards" that +// contain pointers into the owner heap region. Cards are defined somewhat +// abstractly, in terms of what the "BlockOffsetTable" in use can parse. + +class G1CollectedHeap; +class G1BlockOffsetSharedArray; +class HeapRegion; +class HeapRegionRemSetIterator; +class PerRegionTable; +class SparsePRT; +class nmethod; + +// Essentially a wrapper around SparsePRTCleanupTask. See +// sparsePRT.hpp for more details. +class HRRSCleanupTask : public SparsePRTCleanupTask { +}; + +// The FromCardCache remembers the most recently processed card on the heap on +// a per-region and per-thread basis. +class FromCardCache : public AllStatic { + private: + // Array of card indices. Indexed by thread X and heap region to minimize + // thread contention. + static int** _cache; + static uint _max_regions; + static size_t _static_mem_size; + + public: + enum { + InvalidCard = -1 // Card value of an invalid card, i.e. a card index not otherwise used. + }; + + static void clear(uint region_idx); + + // Returns true if the given card is in the cache at the given location, or + // replaces the card at that location and returns false. + static bool contains_or_replace(uint worker_id, uint region_idx, int card) { + int card_in_cache = at(worker_id, region_idx); + if (card_in_cache == card) { + return true; + } else { + set(worker_id, region_idx, card); + return false; + } + } + + static int at(uint worker_id, uint region_idx) { + return _cache[worker_id][region_idx]; + } + + static void set(uint worker_id, uint region_idx, int val) { + _cache[worker_id][region_idx] = val; + } + + static void initialize(uint n_par_rs, uint max_num_regions); + + static void invalidate(uint start_idx, size_t num_regions); + + static void print(outputStream* out = gclog_or_tty) PRODUCT_RETURN; + + static size_t static_mem_size() { + return _static_mem_size; + } +}; + +// The "_coarse_map" is a bitmap with one bit for each region, where set +// bits indicate that the corresponding region may contain some pointer +// into the owning region. + +// The "_fine_grain_entries" array is an open hash table of PerRegionTables +// (PRTs), indicating regions for which we're keeping the RS as a set of +// cards. The strategy is to cap the size of the fine-grain table, +// deleting an entry and setting the corresponding coarse-grained bit when +// we would overflow this cap. + +// We use a mixture of locking and lock-free techniques here. We allow +// threads to locate PRTs without locking, but threads attempting to alter +// a bucket list obtain a lock. This means that any failing attempt to +// find a PRT must be retried with the lock. It might seem dangerous that +// a read can find a PRT that is concurrently deleted. This is all right, +// because: +// +// 1) We only actually free PRT's at safe points (though we reuse them at +// other times). +// 2) We find PRT's in an attempt to add entries. If a PRT is deleted, +// it's _coarse_map bit is set, so the that we were attempting to add +// is represented. If a deleted PRT is re-used, a thread adding a bit, +// thinking the PRT is for a different region, does no harm. + +class OtherRegionsTable VALUE_OBJ_CLASS_SPEC { + friend class HeapRegionRemSetIterator; + + G1CollectedHeap* _g1h; + Mutex* _m; + HeapRegion* _hr; + + // These are protected by "_m". + BitMap _coarse_map; + size_t _n_coarse_entries; + static jint _n_coarsenings; + + PerRegionTable** _fine_grain_regions; + size_t _n_fine_entries; + + // The fine grain remembered sets are doubly linked together using + // their 'next' and 'prev' fields. + // This allows fast bulk freeing of all the fine grain remembered + // set entries, and fast finding of all of them without iterating + // over the _fine_grain_regions table. + PerRegionTable * _first_all_fine_prts; + PerRegionTable * _last_all_fine_prts; + + // Used to sample a subset of the fine grain PRTs to determine which + // PRT to evict and coarsen. + size_t _fine_eviction_start; + static size_t _fine_eviction_stride; + static size_t _fine_eviction_sample_size; + + SparsePRT _sparse_table; + + // These are static after init. + static size_t _max_fine_entries; + static size_t _mod_max_fine_entries_mask; + + // Requires "prt" to be the first element of the bucket list appropriate + // for "hr". If this list contains an entry for "hr", return it, + // otherwise return "NULL". + PerRegionTable* find_region_table(size_t ind, HeapRegion* hr) const; + + // Find, delete, and return a candidate PerRegionTable, if any exists, + // adding the deleted region to the coarse bitmap. Requires the caller + // to hold _m, and the fine-grain table to be full. + PerRegionTable* delete_region_table(); + + // link/add the given fine grain remembered set into the "all" list + void link_to_all(PerRegionTable * prt); + // unlink/remove the given fine grain remembered set into the "all" list + void unlink_from_all(PerRegionTable * prt); + + bool contains_reference_locked(OopOrNarrowOopStar from) const; + + // Clear the from_card_cache entries for this region. + void clear_fcc(); +public: + // Create a new remembered set for the given heap region. The given mutex should + // be used to ensure consistency. + OtherRegionsTable(HeapRegion* hr, Mutex* m); + + // For now. Could "expand" some tables in the future, so that this made + // sense. + void add_reference(OopOrNarrowOopStar from, uint tid); + + // Returns whether the remembered set contains the given reference. + bool contains_reference(OopOrNarrowOopStar from) const; + + // Returns whether this remembered set (and all sub-sets) have an occupancy + // that is less or equal than the given occupancy. + bool occupancy_less_or_equal_than(size_t limit) const; + + // Removes any entries shown by the given bitmaps to contain only dead + // objects. Not thread safe. + // Set bits in the bitmaps indicate that the given region or card is live. + void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); + + // Returns whether this remembered set (and all sub-sets) does not contain any entry. + bool is_empty() const; + + // Returns the number of cards contained in this remembered set. + size_t occupied() const; + size_t occ_fine() const; + size_t occ_coarse() const; + size_t occ_sparse() const; + + static jint n_coarsenings() { return _n_coarsenings; } + + // Returns size of the actual remembered set containers in bytes. + size_t mem_size() const; + // Returns the size of static data in bytes. + static size_t static_mem_size(); + // Returns the size of the free list content in bytes. + static size_t fl_mem_size(); + + // Clear the entire contents of this remembered set. + void clear(); + + void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task); +}; + +class HeapRegionRemSet : public CHeapObj { + friend class VMStructs; + friend class HeapRegionRemSetIterator; + +public: + enum Event { + Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd + }; + +private: + G1BlockOffsetSharedArray* _bosa; + + // A set of code blobs (nmethods) whose code contains pointers into + // the region that owns this RSet. + G1CodeRootSet _code_roots; + + Mutex _m; + + OtherRegionsTable _other_regions; + + enum ParIterState { Unclaimed, Claimed, Complete }; + volatile ParIterState _iter_state; + volatile size_t _iter_claimed; + + // Unused unless G1RecordHRRSOops is true. + + static const int MaxRecorded = 1000000; + static OopOrNarrowOopStar* _recorded_oops; + static HeapWord** _recorded_cards; + static HeapRegion** _recorded_regions; + static int _n_recorded; + + static const int MaxRecordedEvents = 1000; + static Event* _recorded_events; + static int* _recorded_event_index; + static int _n_recorded_events; + + static void print_event(outputStream* str, Event evnt); + +public: + HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, HeapRegion* hr); + + static uint num_par_rem_sets(); + static void setup_remset_size(); + + bool is_empty() const { + return (strong_code_roots_list_length() == 0) && _other_regions.is_empty(); + } + + bool occupancy_less_or_equal_than(size_t occ) const { + return (strong_code_roots_list_length() == 0) && _other_regions.occupancy_less_or_equal_than(occ); + } + + size_t occupied() { + MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); + return occupied_locked(); + } + size_t occupied_locked() { + return _other_regions.occupied(); + } + size_t occ_fine() const { + return _other_regions.occ_fine(); + } + size_t occ_coarse() const { + return _other_regions.occ_coarse(); + } + size_t occ_sparse() const { + return _other_regions.occ_sparse(); + } + + static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); } + + // Used in the sequential case. + void add_reference(OopOrNarrowOopStar from) { + _other_regions.add_reference(from, 0); + } + + // Used in the parallel case. + void add_reference(OopOrNarrowOopStar from, uint tid) { + _other_regions.add_reference(from, tid); + } + + // Removes any entries in the remembered set shown by the given bitmaps to + // contain only dead objects. Not thread safe. + // One bits in the bitmaps indicate that the given region or card is live. + void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); + + // The region is being reclaimed; clear its remset, and any mention of + // entries for this region in other remsets. + void clear(); + void clear_locked(); + + // Attempt to claim the region. Returns true iff this call caused an + // atomic transition from Unclaimed to Claimed. + bool claim_iter(); + // Sets the iteration state to "complete". + void set_iter_complete(); + // Returns "true" iff the region's iteration is complete. + bool iter_is_complete(); + + // Support for claiming blocks of cards during iteration + size_t iter_claimed() const { return _iter_claimed; } + // Claim the next block of cards + size_t iter_claimed_next(size_t step) { + return Atomic::add(step, &_iter_claimed) - step; + } + + void reset_for_par_iteration(); + + bool verify_ready_for_par_iteration() { + return (_iter_state == Unclaimed) && (_iter_claimed == 0); + } + + // The actual # of bytes this hr_remset takes up. + // Note also includes the strong code root set. + size_t mem_size() { + MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); + return _other_regions.mem_size() + // This correction is necessary because the above includes the second + // part. + + (sizeof(HeapRegionRemSet) - sizeof(OtherRegionsTable)) + + strong_code_roots_mem_size(); + } + + // Returns the memory occupancy of all static data structures associated + // with remembered sets. + static size_t static_mem_size() { + return OtherRegionsTable::static_mem_size() + G1CodeRootSet::static_mem_size(); + } + + // Returns the memory occupancy of all free_list data structures associated + // with remembered sets. + static size_t fl_mem_size() { + return OtherRegionsTable::fl_mem_size(); + } + + bool contains_reference(OopOrNarrowOopStar from) const { + return _other_regions.contains_reference(from); + } + + // Routines for managing the list of code roots that point into + // the heap region that owns this RSet. + void add_strong_code_root(nmethod* nm); + void add_strong_code_root_locked(nmethod* nm); + void remove_strong_code_root(nmethod* nm); + + // Applies blk->do_code_blob() to each of the entries in + // the strong code roots list + void strong_code_roots_do(CodeBlobClosure* blk) const; + + void clean_strong_code_roots(HeapRegion* hr); + + // Returns the number of elements in the strong code roots list + size_t strong_code_roots_list_length() const { + return _code_roots.length(); + } + + // Returns true if the strong code roots contains the given + // nmethod. + bool strong_code_roots_list_contains(nmethod* nm) { + return _code_roots.contains(nm); + } + + // Returns the amount of memory, in bytes, currently + // consumed by the strong code roots. + size_t strong_code_roots_mem_size(); + + void print() PRODUCT_RETURN; + + // Called during a stop-world phase to perform any deferred cleanups. + static void cleanup(); + + // Declare the heap size (in # of regions) to the HeapRegionRemSet(s). + // (Uses it to initialize from_card_cache). + static void init_heap(uint max_regions) { + FromCardCache::initialize(num_par_rem_sets(), max_regions); + } + + static void invalidate_from_card_cache(uint start_idx, size_t num_regions) { + FromCardCache::invalidate(start_idx, num_regions); + } + +#ifndef PRODUCT + static void print_from_card_cache() { + FromCardCache::print(); + } +#endif + + static void record(HeapRegion* hr, OopOrNarrowOopStar f); + static void print_recorded(); + static void record_event(Event evnt); + + // These are wrappers for the similarly-named methods on + // SparsePRT. Look at sparsePRT.hpp for more details. + static void reset_for_cleanup_tasks(); + void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task); + static void finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task); + + // Run unit tests. +#ifndef PRODUCT + static void test_prt(); + static void test(); +#endif +}; + +class HeapRegionRemSetIterator : public StackObj { + private: + // The region RSet over which we are iterating. + HeapRegionRemSet* _hrrs; + + // Local caching of HRRS fields. + const BitMap* _coarse_map; + + G1BlockOffsetSharedArray* _bosa; + G1CollectedHeap* _g1h; + + // The number of cards yielded since initialization. + size_t _n_yielded_fine; + size_t _n_yielded_coarse; + size_t _n_yielded_sparse; + + // Indicates what granularity of table that we are currently iterating over. + // We start iterating over the sparse table, progress to the fine grain + // table, and then finish with the coarse table. + enum IterState { + Sparse, + Fine, + Coarse + }; + IterState _is; + + // For both Coarse and Fine remembered set iteration this contains the + // first card number of the heap region we currently iterate over. + size_t _cur_region_card_offset; + + // Current region index for the Coarse remembered set iteration. + int _coarse_cur_region_index; + size_t _coarse_cur_region_cur_card; + + bool coarse_has_next(size_t& card_index); + + // The PRT we are currently iterating over. + PerRegionTable* _fine_cur_prt; + // Card offset within the current PRT. + size_t _cur_card_in_prt; + + // Update internal variables when switching to the given PRT. + void switch_to_prt(PerRegionTable* prt); + bool fine_has_next(); + bool fine_has_next(size_t& card_index); + + // The Sparse remembered set iterator. + SparsePRTIter _sparse_iter; + + public: + HeapRegionRemSetIterator(HeapRegionRemSet* hrrs); + + // If there remains one or more cards to be yielded, returns true and + // sets "card_index" to one of those cards (which is then considered + // yielded.) Otherwise, returns false (and leaves "card_index" + // undefined.) + bool has_next(size_t& card_index); + + size_t n_yielded_fine() { return _n_yielded_fine; } + size_t n_yielded_coarse() { return _n_yielded_coarse; } + size_t n_yielded_sparse() { return _n_yielded_sparse; } + size_t n_yielded() { + return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse(); + } +}; + +#endif // SHARE_VM_GC_G1_HEAPREGIONREMSET_HPP