| /* |
| * 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 |
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| * |
| */ |
| |
| #ifndef SHARE_GC_G1_HEAPREGIONREMSET_HPP |
| #define SHARE_GC_G1_HEAPREGIONREMSET_HPP |
| |
| #include "gc/g1/g1CodeCacheRemSet.hpp" |
| #include "gc/g1/g1FromCardCache.hpp" |
| #include "gc/g1/sparsePRT.hpp" |
| #include "utilities/bitMap.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 PerRegionTable; |
| class SparsePRT; |
| class nmethod; |
| |
| // 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 { |
| G1CollectedHeap* _g1h; |
| Mutex* _m; |
| |
| // 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; |
| |
| size_t occ_fine() const; |
| size_t occ_coarse() const; |
| size_t occ_sparse() const; |
| |
| public: |
| // Create a new remembered set. The given mutex is used to ensure consistency. |
| OtherRegionsTable(Mutex* m); |
| |
| template <class Closure> |
| void iterate(Closure& v); |
| |
| // Returns the card index of the given within_region pointer relative to the bottom |
| // of the given heap region. |
| static CardIdx_t card_within_region(OopOrNarrowOopStar within_region, HeapRegion* hr); |
| // Adds the reference from "from to this remembered set. |
| 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; |
| |
| // 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; |
| |
| 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(); |
| }; |
| |
| class PerRegionTable: public CHeapObj<mtGC> { |
| friend class OtherRegionsTable; |
| |
| HeapRegion* _hr; |
| CHeapBitMap _bm; |
| jint _occupied; |
| |
| // next pointer for free/allocated 'all' list |
| PerRegionTable* _next; |
| |
| // prev pointer for the allocated 'all' list |
| PerRegionTable* _prev; |
| |
| // next pointer in collision list |
| PerRegionTable * _collision_list_next; |
| |
| // Global free list of PRTs |
| static PerRegionTable* volatile _free_list; |
| |
| protected: |
| PerRegionTable(HeapRegion* hr) : |
| _hr(hr), |
| _bm(HeapRegion::CardsPerRegion, mtGC), |
| _occupied(0), |
| _next(NULL), _prev(NULL), |
| _collision_list_next(NULL) |
| {} |
| |
| public: |
| // We need access in order to union things into the base table. |
| BitMap* bm() { return &_bm; } |
| |
| HeapRegion* hr() const { return OrderAccess::load_acquire(&_hr); } |
| |
| jint occupied() const { |
| // Overkill, but if we ever need it... |
| // guarantee(_occupied == _bm.count_one_bits(), "Check"); |
| return _occupied; |
| } |
| |
| void init(HeapRegion* hr, bool clear_links_to_all_list); |
| |
| inline void add_reference(OopOrNarrowOopStar from); |
| |
| inline void add_card(CardIdx_t from_card_index); |
| |
| // (Destructively) union the bitmap of the current table into the given |
| // bitmap (which is assumed to be of the same size.) |
| void union_bitmap_into(BitMap* bm) { |
| bm->set_union(_bm); |
| } |
| |
| // Mem size in bytes. |
| size_t mem_size() const { |
| return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize; |
| } |
| |
| // Requires "from" to be in "hr()". |
| bool contains_reference(OopOrNarrowOopStar from) const { |
| assert(hr()->is_in_reserved(from), "Precondition."); |
| size_t card_ind = pointer_delta(from, hr()->bottom(), |
| G1CardTable::card_size); |
| return _bm.at(card_ind); |
| } |
| |
| // Bulk-free the PRTs from prt to last, assumes that they are |
| // linked together using their _next field. |
| static void bulk_free(PerRegionTable* prt, PerRegionTable* last) { |
| while (true) { |
| PerRegionTable* fl = _free_list; |
| last->set_next(fl); |
| PerRegionTable* res = Atomic::cmpxchg(prt, &_free_list, fl); |
| if (res == fl) { |
| return; |
| } |
| } |
| ShouldNotReachHere(); |
| } |
| |
| static void free(PerRegionTable* prt) { |
| bulk_free(prt, prt); |
| } |
| |
| // Returns an initialized PerRegionTable instance. |
| static PerRegionTable* alloc(HeapRegion* hr); |
| |
| PerRegionTable* next() const { return _next; } |
| void set_next(PerRegionTable* next) { _next = next; } |
| PerRegionTable* prev() const { return _prev; } |
| void set_prev(PerRegionTable* prev) { _prev = prev; } |
| |
| // Accessor and Modification routines for the pointer for the |
| // singly linked collision list that links the PRTs within the |
| // OtherRegionsTable::_fine_grain_regions hash table. |
| // |
| // It might be useful to also make the collision list doubly linked |
| // to avoid iteration over the collisions list during scrubbing/deletion. |
| // OTOH there might not be many collisions. |
| |
| PerRegionTable* collision_list_next() const { |
| return _collision_list_next; |
| } |
| |
| void set_collision_list_next(PerRegionTable* next) { |
| _collision_list_next = next; |
| } |
| |
| PerRegionTable** collision_list_next_addr() { |
| return &_collision_list_next; |
| } |
| |
| static size_t fl_mem_size() { |
| PerRegionTable* cur = _free_list; |
| size_t res = 0; |
| while (cur != NULL) { |
| res += cur->mem_size(); |
| cur = cur->next(); |
| } |
| return res; |
| } |
| |
| static void test_fl_mem_size(); |
| }; |
| |
| class HeapRegionRemSet : public CHeapObj<mtGC> { |
| friend class VMStructs; |
| |
| 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; |
| |
| HeapRegion* _hr; |
| |
| void clear_fcc(); |
| |
| public: |
| HeapRegionRemSet(G1BlockOffsetTable* bot, HeapRegion* hr); |
| |
| // Setup sparse and fine-grain tables sizes. |
| 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); |
| } |
| |
| // For each PRT in the card (remembered) set call one of the following methods |
| // of the given closure: |
| // |
| // set_full_region_dirty(uint region_idx) - pass the region index for coarse PRTs |
| // set_bitmap_dirty(uint region_idx, BitMap* bitmap) - pass the region index and bitmap for fine PRTs |
| // set_cards_dirty(uint region_idx, elem_t* cards, uint num_cards) - pass region index and cards for sparse PRTs |
| template <class Closure> |
| inline void iterate_prts(Closure& cl); |
| |
| size_t occupied() { |
| MutexLocker x(&_m, Mutex::_no_safepoint_check_flag); |
| return occupied_locked(); |
| } |
| size_t occupied_locked() { |
| return _other_regions.occupied(); |
| } |
| |
| static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); } |
| |
| private: |
| enum RemSetState { |
| Untracked, |
| Updating, |
| Complete |
| }; |
| |
| RemSetState _state; |
| |
| static const char* _state_strings[]; |
| static const char* _short_state_strings[]; |
| public: |
| |
| const char* get_state_str() const { return _state_strings[_state]; } |
| const char* get_short_state_str() const { return _short_state_strings[_state]; } |
| |
| bool is_tracked() { return _state != Untracked; } |
| bool is_updating() { return _state == Updating; } |
| bool is_complete() { return _state == Complete; } |
| |
| void set_state_empty() { |
| guarantee(SafepointSynchronize::is_at_safepoint() || !is_tracked(), "Should only set to Untracked during safepoint but is %s.", get_state_str()); |
| if (_state == Untracked) { |
| return; |
| } |
| clear_fcc(); |
| _state = Untracked; |
| } |
| |
| void set_state_updating() { |
| guarantee(SafepointSynchronize::is_at_safepoint() && !is_tracked(), "Should only set to Updating from Untracked during safepoint but is %s", get_state_str()); |
| clear_fcc(); |
| _state = Updating; |
| } |
| |
| void set_state_complete() { |
| clear_fcc(); |
| _state = Complete; |
| } |
| |
| void add_reference(OopOrNarrowOopStar from, uint tid) { |
| RemSetState state = _state; |
| if (state == Untracked) { |
| return; |
| } |
| |
| uint cur_idx = _hr->hrm_index(); |
| uintptr_t from_card = uintptr_t(from) >> CardTable::card_shift; |
| |
| if (G1FromCardCache::contains_or_replace(tid, cur_idx, from_card)) { |
| assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from)); |
| return; |
| } |
| |
| _other_regions.add_reference(from, tid); |
| } |
| |
| // The region is being reclaimed; clear its remset, and any mention of |
| // entries for this region in other remsets. |
| void clear(bool only_cardset = false); |
| void clear_locked(bool only_cardset = false); |
| |
| // The actual # of bytes this hr_remset takes up. |
| // Note also includes the strong code root set. |
| size_t mem_size() { |
| MutexLocker 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(); |
| |
| 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(); |
| } |
| |
| static void test(); |
| #endif |
| }; |
| |
| #endif // SHARE_GC_G1_HEAPREGIONREMSET_HPP |