ysr@777: /*
ysr@777:  * Copyright 2001-2007 Sun Microsystems, Inc.  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:  *
ysr@777:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
ysr@777:  * CA 95054 USA or visit www.sun.com if you need additional information or
ysr@777:  * have any questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
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: 
ysr@777: 
apetrusenko@984: class SparsePRTEntry: public CHeapObj {
ysr@777: public:
ysr@777:   enum SomePublicConstants {
ysr@777:     CardsPerEntry = (short)4,
ysr@777:     NullEntry = (short)-1,
ysr@777:     DeletedEntry = (short)-2
ysr@777:   };
ysr@777: 
ysr@777: private:
ysr@777:   short _region_ind;
ysr@777:   short _next_index;
ysr@777:   short _cards[CardsPerEntry];
ysr@777: 
ysr@777: public:
ysr@777: 
ysr@777:   // Set the region_ind to the given value, and delete all cards.
ysr@777:   inline void init(short region_ind);
ysr@777: 
ysr@777:   short r_ind() const { return _region_ind; }
ysr@777:   bool valid_entry() const { return r_ind() >= 0; }
ysr@777:   void set_r_ind(short rind) { _region_ind = rind; }
ysr@777: 
ysr@777:   short next_index() const { return _next_index; }
ysr@777:   short* next_index_addr() { return &_next_index; }
ysr@777:   void set_next_index(short ni) { _next_index = ni; }
ysr@777: 
ysr@777:   // Returns "true" iff the entry contains the given card index.
ysr@777:   inline bool contains_card(short 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:   };
ysr@777:   inline AddCardResult add_card(short card_index);
ysr@777: 
ysr@777:   // Copy the current entry's cards into "cards".
ysr@777:   inline void copy_cards(short* 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: 
ysr@777:   inline short card(int i) const { return _cards[i]; }
ysr@777: };
ysr@777: 
ysr@777: 
ysr@777: class RSHashTable : public CHeapObj {
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;
ysr@777:   short* _buckets;
ysr@777:   short  _free_region;
ysr@777:   short  _free_list;
ysr@777: 
ysr@777:   static RSHashTable* _head_deleted_list;
ysr@777:   RSHashTable* _next_deleted;
ysr@777:   RSHashTable* next_deleted() { return _next_deleted; }
ysr@777:   void set_next_deleted(RSHashTable* rsht) { _next_deleted = rsht; }
ysr@777:   bool _deleted;
ysr@777:   void set_deleted(bool b) { _deleted = b; }
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."
ysr@777:   SparsePRTEntry* entry_for_region_ind(short 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".
ysr@777:   SparsePRTEntry* entry_for_region_ind_create(short region_ind);
ysr@777: 
ysr@777:   // Returns the index of the next free entry in "_entries".
ysr@777:   short alloc_entry();
ysr@777:   // Declares the entry "fi" to be free.  (It must have already been
ysr@777:   // deleted from any bucket lists.
ysr@777:   void free_entry(short 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.
ysr@777:   bool add_card(short region_id, short card_index);
ysr@777: 
ysr@777:   bool get_cards(short region_id, short* cards);
ysr@777:   bool delete_entry(short region_id);
ysr@777: 
ysr@777:   bool contains_card(short region_id, short card_index) const;
ysr@777: 
ysr@777:   void add_entry(SparsePRTEntry* e);
ysr@777: 
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:   bool deleted() { return _deleted; }
ysr@777: 
ysr@777:   SparsePRTEntry* entry(int i) const { return &_entries[i]; }
ysr@777: 
ysr@777:   void print();
ysr@777: 
ysr@777:   static void add_to_deleted_list(RSHashTable* rsht);
ysr@777:   static RSHashTable* get_from_deleted_list();
ysr@777: 
ysr@777: 
ysr@777: };
ysr@777: 
ysr@777:   // ValueObj because will be embedded in HRRS iterator.
apetrusenko@984: class RSHashTableIter VALUE_OBJ_CLASS_SPEC {
ysr@777:     short _tbl_ind;
ysr@777:     short _bl_ind;
ysr@777:     short _card_ind;
ysr@777:     RSHashTable* _rsht;
ysr@777:     size_t _heap_bot_card_ind;
ysr@777: 
ysr@777:     enum SomePrivateConstants {
ysr@777:       CardsPerRegion = HeapRegion::GrainBytes >> CardTableModRefBS::card_shift
ysr@777:     };
ysr@777: 
ysr@777:     // If the bucket list pointed to by _bl_ind contains a card, sets
ysr@777:     // _bl_ind to the index of that entry, and returns the card.
ysr@777:     // Otherwise, returns SparseEntry::NullEnty.
ysr@777:     short find_first_card_in_list();
ysr@777:     // Computes the proper card index for the card whose offset in the
ysr@777:     // current region (as indicated by _bl_ind) is "ci".
ysr@777:     // This is subject to errors when there is iteration concurrent with
ysr@777:     // modification, but these errors should be benign.
ysr@777:     size_t compute_card_ind(short ci);
ysr@777: 
ysr@777:   public:
ysr@777:     RSHashTableIter(size_t heap_bot_card_ind) :
ysr@777:       _tbl_ind(RSHashTable::NullEntry),
ysr@777:       _bl_ind(RSHashTable::NullEntry),
ysr@777:       _card_ind((SparsePRTEntry::CardsPerEntry-1)),
ysr@777:       _rsht(NULL),
ysr@777:       _heap_bot_card_ind(heap_bot_card_ind)
ysr@777:     {}
ysr@777: 
ysr@777:     void init(RSHashTable* rsht) {
ysr@777:       _rsht = rsht;
ysr@777:       _tbl_ind = -1; // So that first increment gets to 0.
ysr@777:       _bl_ind = RSHashTable::NullEntry;
ysr@777:       _card_ind = (SparsePRTEntry::CardsPerEntry-1);
ysr@777:     }
ysr@777: 
ysr@777:     bool has_next(size_t& card_index);
ysr@777: 
ysr@777:   };
ysr@777: 
ysr@777: // Concurrent accesss to a SparsePRT must be serialized by some external
ysr@777: // mutex.
ysr@777: 
ysr@777: class SparsePRTIter;
ysr@777: 
apetrusenko@984: class SparsePRT VALUE_OBJ_CLASS_SPEC {
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: 
ysr@777: 
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.
ysr@777:   bool add_card(short region_id, short 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
ysr@777:   // "CardsPerEntry", and returns "true"; otherwise, returns "false".
ysr@777:   bool get_cards(short region_ind, short* cards);
ysr@777: 
ysr@777:   // If there is an entry for "region_ind", removes it and return "true";
ysr@777:   // otherwise returns "false."
ysr@777:   bool delete_entry(short 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: 
ysr@777:   void init_iterator(SparsePRTIter* sprt_iter);
ysr@777: 
ysr@777:   static void add_to_expanded_list(SparsePRT* sprt);
ysr@777:   static SparsePRT* get_from_expanded_list();
ysr@777: 
ysr@777:   bool contains_card(short region_id, short card_index) const {
ysr@777:     return _next->contains_card(region_id, card_index);
ysr@777:   }
ysr@777: 
ysr@777: #if 0
ysr@777:   void verify_is_cleared();
ysr@777:   void print();
ysr@777: #endif
ysr@777: };
ysr@777: 
ysr@777: 
ysr@777: class SparsePRTIter: public /* RSHashTable:: */RSHashTableIter {
ysr@777: public:
ysr@777:   SparsePRTIter(size_t heap_bot_card_ind) :
ysr@777:     /* RSHashTable:: */RSHashTableIter(heap_bot_card_ind)
ysr@777:   {}
ysr@777: 
ysr@777:   void init(const SparsePRT* sprt) {
tonyp@1052:     RSHashTableIter::init(sprt->cur());
ysr@777:   }
ysr@777:   bool has_next(size_t& card_index) {
ysr@777:     return RSHashTableIter::has_next(card_index);
ysr@777:   }
ysr@777: };