| /* |
| * Copyright (c) 2001, 2017, 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 |
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| */ |
| |
| #ifndef SHARE_VM_GC_G1_HEAPREGIONREMSET_HPP |
| #define SHARE_VM_GC_G1_HEAPREGIONREMSET_HPP |
| |
| #include "gc/g1/g1CodeCacheRemSet.hpp" |
| #include "gc/g1/g1FromCardCache.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 G1BlockOffsetTable; |
| class G1CardLiveData; |
| 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 "_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". |
| CHeapBitMap _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(G1CardLiveData* live_data); |
| |
| // 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<mtGC> { |
| friend class VMStructs; |
| friend class HeapRegionRemSetIterator; |
| |
| private: |
| G1BlockOffsetTable* _bot; |
| |
| // 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; |
| |
| public: |
| HeapRegionRemSet(G1BlockOffsetTable* bot, HeapRegion* hr); |
| |
| 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 card live data to |
| // contain only dead objects. Not thread safe. |
| void scrub(G1CardLiveData* live_data); |
| |
| // The region is being reclaimed; clear its remset, and any mention of |
| // entries for this region in other remsets. |
| void clear(); |
| void clear_locked(); |
| |
| // 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(); |
| |
| // Called during a stop-world phase to perform any deferred cleanups. |
| static void cleanup(); |
| |
| static void invalidate_from_card_cache(uint start_idx, size_t num_regions) { |
| G1FromCardCache::invalidate(start_idx, num_regions); |
| } |
| |
| #ifndef PRODUCT |
| static void print_from_card_cache() { |
| G1FromCardCache::print(); |
| } |
| #endif |
| |
| // 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(); |
| #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; |
| |
| G1BlockOffsetTable* _bot; |
| 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 |