jdk8-mips64-public/hotspot: comparison src/share/vm/gc

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+:f90c822e73f8
+/*
+* Copyright (c) 2001, 2013, 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_SPARSEPRT_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_SPARSEPRT_HPP
+#include "gc_implementation/g1/g1CollectedHeap.hpp"
+#include "gc_implementation/g1/heapRegion.hpp"
+#include "memory/allocation.hpp"
+#include "memory/cardTableModRefBS.hpp"
+#include "runtime/mutex.hpp"
+#include "utilities/globalDefinitions.hpp"
+// Sparse remembered set for a heap region (the "owning" region).  Maps
+// indices of other regions to short sequences of cards in the other region
+// that might contain pointers into the owner region.
+// These tables only expand while they are accessed in parallel --
+// deletions may be done in single-threaded code.  This allows us to allow
+// unsynchronized reads/iterations, as long as expansions caused by
+// insertions only enqueue old versions for deletions, but do not delete
+// old versions synchronously.
+class SparsePRTEntry: public CHeapObj<mtGC> {
+public:
+enum SomePublicConstants {
+NullEntry     = -1,
+UnrollFactor  =  4
+};
+private:
+RegionIdx_t _region_ind;
+int         _next_index;
+CardIdx_t   _cards[1];
+// WARNING: Don't put any data members beyond this line. Card array has, in fact, variable length.
+// It should always be the last data member.
+public:
+// Returns the size of the entry, used for entry allocation.
+static size_t size() { return sizeof(SparsePRTEntry) + sizeof(CardIdx_t) * (cards_num() - 1); }
+// Returns the size of the card array.
+static int cards_num() {
+// The number of cards should be a multiple of 4, because that's our current
+// unrolling factor.
+static const int s = MAX2<int>(G1RSetSparseRegionEntries & ~(UnrollFactor - 1), UnrollFactor);
+return s;
+}
+// Set the region_ind to the given value, and delete all cards.
+inline void init(RegionIdx_t region_ind);
+RegionIdx_t r_ind() const { return _region_ind; }
+bool valid_entry() const { return r_ind() >= 0; }
+void set_r_ind(RegionIdx_t rind) { _region_ind = rind; }
+int next_index() const { return _next_index; }
+int* next_index_addr() { return &_next_index; }
+void set_next_index(int ni) { _next_index = ni; }
+// Returns "true" iff the entry contains the given card index.
+inline bool contains_card(CardIdx_t card_index) const;
+// Returns the number of non-NULL card entries.
+inline int num_valid_cards() const;
+// Requires that the entry not contain the given card index.  If there is
+// space available, add the given card index to the entry and return
+// "true"; otherwise, return "false" to indicate that the entry is full.
+enum AddCardResult {
+overflow,
+found,
+added
+};
+inline AddCardResult add_card(CardIdx_t card_index);
+// Copy the current entry's cards into "cards".
+inline void copy_cards(CardIdx_t* cards) const;
+// Copy the current entry's cards into the "_card" array of "e."
+inline void copy_cards(SparsePRTEntry* e) const;
+inline CardIdx_t card(int i) const { return _cards[i]; }
+};
+class RSHashTable : public CHeapObj<mtGC> {
+friend class RSHashTableIter;
+enum SomePrivateConstants {
+NullEntry = -1
+};
+size_t _capacity;
+size_t _capacity_mask;
+size_t _occupied_entries;
+size_t _occupied_cards;
+SparsePRTEntry* _entries;
+int* _buckets;
+int  _free_region;
+int  _free_list;
+// Requires that the caller hold a lock preventing parallel modifying
+// operations, and that the the table be less than completely full.  If
+// an entry for "region_ind" is already in the table, finds it and
+// returns its address; otherwise returns "NULL."
+SparsePRTEntry* entry_for_region_ind(RegionIdx_t region_ind) const;
+// Requires that the caller hold a lock preventing parallel modifying
+// operations, and that the the table be less than completely full.  If
+// an entry for "region_ind" is already in the table, finds it and
+// returns its address; otherwise allocates, initializes, inserts and
+// returns a new entry for "region_ind".
+SparsePRTEntry* entry_for_region_ind_create(RegionIdx_t region_ind);
+// Returns the index of the next free entry in "_entries".
+int alloc_entry();
+// Declares the entry "fi" to be free.  (It must have already been
+// deleted from any bucket lists.
+void free_entry(int fi);
+public:
+RSHashTable(size_t capacity);
+~RSHashTable();
+// Attempts to ensure that the given card_index in the given region is in
+// the sparse table.  If successful (because the card was already
+// present, or because it was successfullly added) returns "true".
+// Otherwise, returns "false" to indicate that the addition would
+// overflow the entry for the region.  The caller must transfer these
+// entries to a larger-capacity representation.
+bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
+bool get_cards(RegionIdx_t region_id, CardIdx_t* cards);
+bool delete_entry(RegionIdx_t region_id);
+bool contains_card(RegionIdx_t region_id, CardIdx_t card_index) const;
+void add_entry(SparsePRTEntry* e);
+SparsePRTEntry* get_entry(RegionIdx_t region_id);
+void clear();
+size_t capacity() const      { return _capacity;       }
+size_t capacity_mask() const { return _capacity_mask;  }
+size_t occupied_entries() const { return _occupied_entries; }
+size_t occupied_cards() const   { return _occupied_cards;   }
+size_t mem_size() const;
+SparsePRTEntry* entry(int i) const { return (SparsePRTEntry*)((char*)_entries + SparsePRTEntry::size() * i); }
+void print();
+};
+// ValueObj because will be embedded in HRRS iterator.
+class RSHashTableIter VALUE_OBJ_CLASS_SPEC {
+int _tbl_ind;         // [-1, 0.._rsht->_capacity)
+int _bl_ind;          // [-1, 0.._rsht->_capacity)
+short _card_ind;      // [0..SparsePRTEntry::cards_num())
+RSHashTable* _rsht;
+// If the bucket list pointed to by _bl_ind contains a card, sets
+// _bl_ind to the index of that entry, and returns the card.
+// Otherwise, returns SparseEntry::NullEntry.
+CardIdx_t find_first_card_in_list();
+// Computes the proper card index for the card whose offset in the
+// current region (as indicated by _bl_ind) is "ci".
+// This is subject to errors when there is iteration concurrent with
+// modification, but these errors should be benign.
+size_t compute_card_ind(CardIdx_t ci);
+public:
+RSHashTableIter(RSHashTable* rsht) :
+_tbl_ind(RSHashTable::NullEntry), // So that first increment gets to 0.
+_bl_ind(RSHashTable::NullEntry),
+_card_ind((SparsePRTEntry::cards_num() - 1)),
+_rsht(rsht) {}
+bool has_next(size_t& card_index);
+};
+// Concurrent accesss to a SparsePRT must be serialized by some external
+// mutex.
+class SparsePRTIter;
+class SparsePRTCleanupTask;
+class SparsePRT VALUE_OBJ_CLASS_SPEC {
+friend class SparsePRTCleanupTask;
+//  Iterations are done on the _cur hash table, since they only need to
+//  see entries visible at the start of a collection pause.
+//  All other operations are done using the _next hash table.
+RSHashTable* _cur;
+RSHashTable* _next;
+HeapRegion* _hr;
+enum SomeAdditionalPrivateConstants {
+InitialCapacity = 16
+};
+void expand();
+bool _expanded;
+bool expanded() { return _expanded; }
+void set_expanded(bool b) { _expanded = b; }
+SparsePRT* _next_expanded;
+SparsePRT* next_expanded() { return _next_expanded; }
+void set_next_expanded(SparsePRT* nxt) { _next_expanded = nxt; }
+bool should_be_on_expanded_list();
+static SparsePRT* _head_expanded_list;
+public:
+SparsePRT(HeapRegion* hr);
+~SparsePRT();
+size_t occupied() const { return _next->occupied_cards(); }
+size_t mem_size() const;
+// Attempts to ensure that the given card_index in the given region is in
+// the sparse table.  If successful (because the card was already
+// present, or because it was successfullly added) returns "true".
+// Otherwise, returns "false" to indicate that the addition would
+// overflow the entry for the region.  The caller must transfer these
+// entries to a larger-capacity representation.
+bool add_card(RegionIdx_t region_id, CardIdx_t card_index);
+// If the table hold an entry for "region_ind",  Copies its
+// cards into "cards", which must be an array of length at least
+// "SparePRTEntry::cards_num()", and returns "true"; otherwise,
+// returns "false".
+bool get_cards(RegionIdx_t region_ind, CardIdx_t* cards);
+// Return the pointer to the entry associated with the given region.
+SparsePRTEntry* get_entry(RegionIdx_t region_ind);
+// If there is an entry for "region_ind", removes it and return "true";
+// otherwise returns "false."
+bool delete_entry(RegionIdx_t region_ind);
+// Clear the table, and reinitialize to initial capacity.
+void clear();
+// Ensure that "_cur" and "_next" point to the same table.
+void cleanup();
+// Clean up all tables on the expanded list.  Called single threaded.
+static void cleanup_all();
+RSHashTable* cur() const { return _cur; }
+static void add_to_expanded_list(SparsePRT* sprt);
+static SparsePRT* get_from_expanded_list();
+// The purpose of these three methods is to help the GC workers
+// during the cleanup pause to recreate the expanded list, purging
+// any tables from it that belong to regions that are freed during
+// cleanup (if we don't purge those tables, there is a race that
+// causes various crashes; see CR 7014261).
+//
+// We chose to recreate the expanded list, instead of purging
+// entries from it by iterating over it, to avoid this serial phase
+// at the end of the cleanup pause.
+//
+// The three methods below work as follows:
+// * reset_for_cleanup_tasks() : Nulls the expanded list head at the
+//   start of the cleanup pause.
+// * do_cleanup_work() : Called by the cleanup workers for every
+//   region that is not free / is being freed by the cleanup
+//   pause. It creates a list of expanded tables whose head / tail
+//   are on the thread-local SparsePRTCleanupTask object.
+// * finish_cleanup_task() : Called by the cleanup workers after
+//   they complete their cleanup task. It adds the local list into
+//   the global expanded list. It assumes that the
+//   ParGCRareEvent_lock is being held to ensure MT-safety.
+static void reset_for_cleanup_tasks();
+void do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task);
+static void finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task);
+bool contains_card(RegionIdx_t region_id, CardIdx_t card_index) const {
+return _next->contains_card(region_id, card_index);
+}
+};
+class SparsePRTIter: public RSHashTableIter {
+public:
+SparsePRTIter(const SparsePRT* sprt) :
+RSHashTableIter(sprt->cur()) {}
+bool has_next(size_t& card_index) {
+return RSHashTableIter::has_next(card_index);
+}
+};
+// This allows each worker during a cleanup pause to create a
+// thread-local list of sparse tables that have been expanded and need
+// to be processed at the beginning of the next GC pause. This lists
+// are concatenated into the single expanded list at the end of the
+// cleanup pause.
+class SparsePRTCleanupTask VALUE_OBJ_CLASS_SPEC {
+private:
+SparsePRT* _head;
+SparsePRT* _tail;
+public:
+SparsePRTCleanupTask() : _head(NULL), _tail(NULL) { }
+void add(SparsePRT* sprt);
+SparsePRT* head() { return _head; }
+SparsePRT* tail() { return _tail; }
+};
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_SPARSEPRT_HPP

comparison: src/share/vm/gc_implementation/g1/sparsePRT.hpp

src/share/vm/gc_implementation/g1/sparsePRT.hpp

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/gc_implementation/g1/sparsePRT.hpp

src/share/vm/gc_implementation/g1/sparsePRT.hpp