ysr@777: /*
mikael@6198:  * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SPARSEPRT_HPP
stefank@2314: #define SHARE_VM_GC_IMPLEMENTATION_G1_SPARSEPRT_HPP
stefank@2314: 
tschatzl@6541: #include "gc_implementation/g1/g1CollectedHeap.hpp"
stefank@2314: #include "gc_implementation/g1/heapRegion.hpp"
stefank@2314: #include "memory/allocation.hpp"
stefank@2314: #include "memory/cardTableModRefBS.hpp"
stefank@2314: #include "runtime/mutex.hpp"
stefank@2314: #include "utilities/globalDefinitions.hpp"
stefank@2314: 
ysr@777: // Sparse remembered set for a heap region (the "owning" region).  Maps
ysr@777: // indices of other regions to short sequences of cards in the other region
ysr@777: // that might contain pointers into the owner region.
ysr@777: 
ysr@777: // These tables only expand while they are accessed in parallel --
ysr@777: // deletions may be done in single-threaded code.  This allows us to allow
ysr@777: // unsynchronized reads/iterations, as long as expansions caused by
ysr@777: // insertions only enqueue old versions for deletions, but do not delete
ysr@777: // old versions synchronously.
ysr@777: 
zgu@3900: class SparsePRTEntry: public CHeapObj<mtGC> {
ysr@777: public:
ysr@777:   enum SomePublicConstants {
iveresov@1696:     NullEntry     = -1,
iveresov@1696:     UnrollFactor  =  4
ysr@777:   };
ysr@777: private:
johnc@1242:   RegionIdx_t _region_ind;
johnc@1242:   int         _next_index;
iveresov@1696:   CardIdx_t   _cards[1];
iveresov@1696:   // WARNING: Don't put any data members beyond this line. Card array has, in fact, variable length.
iveresov@1696:   // It should always be the last data member.
ysr@777: public:
iveresov@1696:   // Returns the size of the entry, used for entry allocation.
iveresov@1696:   static size_t size() { return sizeof(SparsePRTEntry) + sizeof(CardIdx_t) * (cards_num() - 1); }
iveresov@1696:   // Returns the size of the card array.
iveresov@1696:   static int cards_num() {
iveresov@1696:     // The number of cards should be a multiple of 4, because that's our current
iveresov@1696:     // unrolling factor.
iveresov@1696:     static const int s = MAX2<int>(G1RSetSparseRegionEntries & ~(UnrollFactor - 1), UnrollFactor);
iveresov@1696:     return s;
iveresov@1696:   }
ysr@777: 
ysr@777:   // Set the region_ind to the given value, and delete all cards.
johnc@1242:   inline void init(RegionIdx_t region_ind);
ysr@777: 
johnc@1242:   RegionIdx_t r_ind() const { return _region_ind; }
ysr@777:   bool valid_entry() const { return r_ind() >= 0; }
johnc@1242:   void set_r_ind(RegionIdx_t rind) { _region_ind = rind; }
ysr@777: 
johnc@1242:   int next_index() const { return _next_index; }
johnc@1242:   int* next_index_addr() { return &_next_index; }
johnc@1242:   void set_next_index(int ni) { _next_index = ni; }
ysr@777: 
ysr@777:   // Returns "true" iff the entry contains the given card index.
johnc@1242:   inline bool contains_card(CardIdx_t card_index) const;
ysr@777: 
ysr@777:   // Returns the number of non-NULL card entries.
ysr@777:   inline int num_valid_cards() const;
ysr@777: 
ysr@777:   // Requires that the entry not contain the given card index.  If there is
ysr@777:   // space available, add the given card index to the entry and return
ysr@777:   // "true"; otherwise, return "false" to indicate that the entry is full.
ysr@777:   enum AddCardResult {
ysr@777:     overflow,
ysr@777:     found,
ysr@777:     added
ysr@777:   };
johnc@1242:   inline AddCardResult add_card(CardIdx_t card_index);
ysr@777: 
ysr@777:   // Copy the current entry's cards into "cards".
johnc@1242:   inline void copy_cards(CardIdx_t* cards) const;
ysr@777:   // Copy the current entry's cards into the "_card" array of "e."
ysr@777:   inline void copy_cards(SparsePRTEntry* e) const;
ysr@777: 
johnc@1242:   inline CardIdx_t card(int i) const { return _cards[i]; }
ysr@777: };
ysr@777: 
ysr@777: 
zgu@3900: class RSHashTable : public CHeapObj<mtGC> {
ysr@777: 
ysr@777:   friend class RSHashTableIter;
ysr@777: 
ysr@777:   enum SomePrivateConstants {
ysr@777:     NullEntry = -1
ysr@777:   };
ysr@777: 
ysr@777:   size_t _capacity;
ysr@777:   size_t _capacity_mask;
ysr@777:   size_t _occupied_entries;
ysr@777:   size_t _occupied_cards;
ysr@777: 
ysr@777:   SparsePRTEntry* _entries;
johnc@1242:   int* _buckets;
johnc@1242:   int  _free_region;
johnc@1242:   int  _free_list;
ysr@777: 
ysr@777:   // Requires that the caller hold a lock preventing parallel modifying
ysr@777:   // operations, and that the the table be less than completely full.  If
ysr@777:   // an entry for "region_ind" is already in the table, finds it and
ysr@777:   // returns its address; otherwise returns "NULL."
johnc@1242:   SparsePRTEntry* entry_for_region_ind(RegionIdx_t region_ind) const;
ysr@777: 
ysr@777:   // Requires that the caller hold a lock preventing parallel modifying
ysr@777:   // operations, and that the the table be less than completely full.  If
ysr@777:   // an entry for "region_ind" is already in the table, finds it and
ysr@777:   // returns its address; otherwise allocates, initializes, inserts and
ysr@777:   // returns a new entry for "region_ind".
johnc@1242:   SparsePRTEntry* entry_for_region_ind_create(RegionIdx_t region_ind);
ysr@777: 
ysr@777:   // Returns the index of the next free entry in "_entries".
johnc@1242:   int alloc_entry();
ysr@777:   // Declares the entry "fi" to be free.  (It must have already been
ysr@777:   // deleted from any bucket lists.
johnc@1242:   void free_entry(int fi);
ysr@777: 
ysr@777: public:
ysr@777:   RSHashTable(size_t capacity);
ysr@777:   ~RSHashTable();
ysr@777: 
ysr@777:   // Attempts to ensure that the given card_index in the given region is in
ysr@777:   // the sparse table.  If successful (because the card was already
ysr@777:   // present, or because it was successfullly added) returns "true".
ysr@777:   // Otherwise, returns "false" to indicate that the addition would
ysr@777:   // overflow the entry for the region.  The caller must transfer these
ysr@777:   // entries to a larger-capacity representation.
johnc@1242:   bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
ysr@777: 
johnc@1242:   bool get_cards(RegionIdx_t region_id, CardIdx_t* cards);
iveresov@1696: 
johnc@1242:   bool delete_entry(RegionIdx_t region_id);
ysr@777: 
johnc@1242:   bool contains_card(RegionIdx_t region_id, CardIdx_t card_index) const;
ysr@777: 
ysr@777:   void add_entry(SparsePRTEntry* e);
ysr@777: 
iveresov@1696:   SparsePRTEntry* get_entry(RegionIdx_t region_id);
iveresov@1696: 
ysr@777:   void clear();
ysr@777: 
ysr@777:   size_t capacity() const      { return _capacity;       }
ysr@777:   size_t capacity_mask() const { return _capacity_mask;  }
ysr@777:   size_t occupied_entries() const { return _occupied_entries; }
ysr@777:   size_t occupied_cards() const   { return _occupied_cards;   }
ysr@777:   size_t mem_size() const;
ysr@777: 
iveresov@1696:   SparsePRTEntry* entry(int i) const { return (SparsePRTEntry*)((char*)_entries + SparsePRTEntry::size() * i); }
ysr@777: 
ysr@777:   void print();
ysr@777: };
ysr@777: 
johnc@1242: // ValueObj because will be embedded in HRRS iterator.
apetrusenko@984: class RSHashTableIter VALUE_OBJ_CLASS_SPEC {
johnc@1242:   int _tbl_ind;         // [-1, 0.._rsht->_capacity)
johnc@1242:   int _bl_ind;          // [-1, 0.._rsht->_capacity)
iveresov@1696:   short _card_ind;      // [0..SparsePRTEntry::cards_num())
johnc@1242:   RSHashTable* _rsht;
ysr@777: 
johnc@1242:   // If the bucket list pointed to by _bl_ind contains a card, sets
johnc@1242:   // _bl_ind to the index of that entry, and returns the card.
johnc@1242:   // Otherwise, returns SparseEntry::NullEntry.
johnc@1242:   CardIdx_t find_first_card_in_list();
ysr@777: 
johnc@1242:   // Computes the proper card index for the card whose offset in the
johnc@1242:   // current region (as indicated by _bl_ind) is "ci".
johnc@1242:   // This is subject to errors when there is iteration concurrent with
johnc@1242:   // modification, but these errors should be benign.
johnc@1242:   size_t compute_card_ind(CardIdx_t ci);
ysr@777: 
johnc@1242: public:
johnc@5014:   RSHashTableIter(RSHashTable* rsht) :
johnc@5014:     _tbl_ind(RSHashTable::NullEntry), // So that first increment gets to 0.
johnc@1242:     _bl_ind(RSHashTable::NullEntry),
iveresov@1696:     _card_ind((SparsePRTEntry::cards_num() - 1)),
johnc@5014:     _rsht(rsht) {}
ysr@777: 
johnc@1242:   bool has_next(size_t& card_index);
johnc@1242: };
ysr@777: 
ysr@777: // Concurrent accesss to a SparsePRT must be serialized by some external
ysr@777: // mutex.
ysr@777: 
ysr@777: class SparsePRTIter;
tonyp@2493: class SparsePRTCleanupTask;
ysr@777: 
apetrusenko@984: class SparsePRT VALUE_OBJ_CLASS_SPEC {
tonyp@2493:   friend class SparsePRTCleanupTask;
tonyp@2493: 
ysr@777:   //  Iterations are done on the _cur hash table, since they only need to
ysr@777:   //  see entries visible at the start of a collection pause.
ysr@777:   //  All other operations are done using the _next hash table.
ysr@777:   RSHashTable* _cur;
ysr@777:   RSHashTable* _next;
ysr@777: 
ysr@777:   HeapRegion* _hr;
ysr@777: 
ysr@777:   enum SomeAdditionalPrivateConstants {
ysr@777:     InitialCapacity = 16
ysr@777:   };
ysr@777: 
ysr@777:   void expand();
ysr@777: 
ysr@777:   bool _expanded;
ysr@777: 
ysr@777:   bool expanded() { return _expanded; }
ysr@777:   void set_expanded(bool b) { _expanded = b; }
ysr@777: 
ysr@777:   SparsePRT* _next_expanded;
ysr@777: 
ysr@777:   SparsePRT* next_expanded() { return _next_expanded; }
ysr@777:   void set_next_expanded(SparsePRT* nxt) { _next_expanded = nxt; }
ysr@777: 
tonyp@2493:   bool should_be_on_expanded_list();
tonyp@2493: 
ysr@777:   static SparsePRT* _head_expanded_list;
ysr@777: 
ysr@777: public:
ysr@777:   SparsePRT(HeapRegion* hr);
ysr@777: 
ysr@777:   ~SparsePRT();
ysr@777: 
ysr@777:   size_t occupied() const { return _next->occupied_cards(); }
ysr@777:   size_t mem_size() const;
ysr@777: 
ysr@777:   // Attempts to ensure that the given card_index in the given region is in
ysr@777:   // the sparse table.  If successful (because the card was already
ysr@777:   // present, or because it was successfullly added) returns "true".
ysr@777:   // Otherwise, returns "false" to indicate that the addition would
ysr@777:   // overflow the entry for the region.  The caller must transfer these
ysr@777:   // entries to a larger-capacity representation.
johnc@1242:   bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
ysr@777: 
ysr@777:   // If the table hold an entry for "region_ind",  Copies its
ysr@777:   // cards into "cards", which must be an array of length at least
iveresov@1696:   // "SparePRTEntry::cards_num()", and returns "true"; otherwise,
iveresov@1696:   // returns "false".
johnc@1242:   bool get_cards(RegionIdx_t region_ind, CardIdx_t* cards);
ysr@777: 
iveresov@1696:   // Return the pointer to the entry associated with the given region.
iveresov@1696:   SparsePRTEntry* get_entry(RegionIdx_t region_ind);
iveresov@1696: 
ysr@777:   // If there is an entry for "region_ind", removes it and return "true";
ysr@777:   // otherwise returns "false."
johnc@1242:   bool delete_entry(RegionIdx_t region_ind);
ysr@777: 
ysr@777:   // Clear the table, and reinitialize to initial capacity.
ysr@777:   void clear();
ysr@777: 
ysr@777:   // Ensure that "_cur" and "_next" point to the same table.
ysr@777:   void cleanup();
ysr@777: 
ysr@777:   // Clean up all tables on the expanded list.  Called single threaded.
ysr@777:   static void cleanup_all();
tonyp@1052:   RSHashTable* cur() const { return _cur; }
ysr@777: 
ysr@777:   static void add_to_expanded_list(SparsePRT* sprt);
ysr@777:   static SparsePRT* get_from_expanded_list();
ysr@777: 
tonyp@2493:   // The purpose of these three methods is to help the GC workers
tonyp@2493:   // during the cleanup pause to recreate the expanded list, purging
tonyp@2493:   // any tables from it that belong to regions that are freed during
tonyp@2493:   // cleanup (if we don't purge those tables, there is a race that
tonyp@2493:   // causes various crashes; see CR 7014261).
tonyp@2493:   //
tonyp@2493:   // We chose to recreate the expanded list, instead of purging
tonyp@2493:   // entries from it by iterating over it, to avoid this serial phase
tonyp@2493:   // at the end of the cleanup pause.
tonyp@2493:   //
tonyp@2493:   // The three methods below work as follows:
tonyp@2493:   // * reset_for_cleanup_tasks() : Nulls the expanded list head at the
tonyp@2493:   //   start of the cleanup pause.
tonyp@2493:   // * do_cleanup_work() : Called by the cleanup workers for every
tonyp@2493:   //   region that is not free / is being freed by the cleanup
tonyp@2493:   //   pause. It creates a list of expanded tables whose head / tail
tonyp@2493:   //   are on the thread-local SparsePRTCleanupTask object.
tonyp@2493:   // * finish_cleanup_task() : Called by the cleanup workers after
tonyp@2493:   //   they complete their cleanup task. It adds the local list into
tonyp@2493:   //   the global expanded list. It assumes that the
tonyp@2493:   //   ParGCRareEvent_lock is being held to ensure MT-safety.
tonyp@2493:   static void reset_for_cleanup_tasks();
tonyp@2493:   void do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task);
tonyp@2493:   static void finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task);
tonyp@2493: 
johnc@1242:   bool contains_card(RegionIdx_t region_id, CardIdx_t card_index) const {
ysr@777:     return _next->contains_card(region_id, card_index);
ysr@777:   }
ysr@777: };
ysr@777: 
tonyp@2239: class SparsePRTIter: public RSHashTableIter {
ysr@777: public:
johnc@5014:   SparsePRTIter(const SparsePRT* sprt) :
johnc@5014:     RSHashTableIter(sprt->cur()) {}
johnc@5014: 
ysr@777:   bool has_next(size_t& card_index) {
ysr@777:     return RSHashTableIter::has_next(card_index);
ysr@777:   }
ysr@777: };
stefank@2314: 
tonyp@2493: // This allows each worker during a cleanup pause to create a
tonyp@2493: // thread-local list of sparse tables that have been expanded and need
tonyp@2493: // to be processed at the beginning of the next GC pause. This lists
tonyp@2493: // are concatenated into the single expanded list at the end of the
tonyp@2493: // cleanup pause.
tonyp@2493: class SparsePRTCleanupTask VALUE_OBJ_CLASS_SPEC {
tonyp@2493: private:
tonyp@2493:   SparsePRT* _head;
tonyp@2493:   SparsePRT* _tail;
tonyp@2493: 
tonyp@2493: public:
tonyp@2493:   SparsePRTCleanupTask() : _head(NULL), _tail(NULL) { }
tonyp@2493: 
tonyp@2493:   void add(SparsePRT* sprt);
tonyp@2493:   SparsePRT* head() { return _head; }
tonyp@2493:   SparsePRT* tail() { return _tail; }
tonyp@2493: };
tonyp@2493: 
stefank@2314: #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SPARSEPRT_HPP