jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp@8a5ea0a9ccc4 (annotated)

src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp@8a5ea0a9ccc4 (annotated)

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

Sat, 06 Oct 2012 01:17:44 -0700

author: johnc
date: Sat, 06 Oct 2012 01:17:44 -0700
changeset 4173: 8a5ea0a9ccc4
parent 3956: db823a892a55
child 5014: 5c93c1f61226
permissions: -rw-r--r--

7127708: G1: change task num types from int to uint in concurrent mark
Summary: Change the type of various task num fields, parameters etc to unsigned and rename them to be more consistent with the other collectors. Code changes were also reviewed by Vitaly Davidovich.
Reviewed-by: johnc
Contributed-by: Kaushik Srenevasan <kaushik@twitter.com>

 /*
  * Copyright (c) 2001, 2012, 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_HEAPREGIONREMSET_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
 #include "gc_implementation/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 G1BlockOffsetSharedArray;
 class HeapRegion;
 class HeapRegionRemSetIterator;
 class PerRegionTable;
 class SparsePRT;
 // 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".
   BitMap      _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();
   // If a PRT for "hr" is in the bucket list indicated by "ind" (which must
   // be the correct index for "hr"), delete it and return true; else return
   // false.
   bool del_single_region_table(size_t ind, HeapRegion* hr);
   // Indexed by thread X heap region, to minimize thread contention.
   static int** _from_card_cache;
   static size_t _from_card_cache_max_regions;
   static size_t _from_card_cache_mem_size;
   // 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);
 public:
   OtherRegionsTable(HeapRegion* hr);
   HeapRegion* hr() const { return _hr; }
   // For now.  Could "expand" some tables in the future, so that this made
   // sense.
   void add_reference(OopOrNarrowOopStar from, int tid);
   // Removes any entries shown by the given bitmaps to contain only dead
   // objects.
   void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
   // Not const because it takes a lock.
   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 in bytes.
   // Not const because it takes a lock.
   size_t mem_size() const;
   static size_t static_mem_size();
   static size_t fl_mem_size();
   bool contains_reference(OopOrNarrowOopStar from) const;
   bool contains_reference_locked(OopOrNarrowOopStar from) const;
   void clear();
   // Specifically clear the from_card_cache.
   void clear_fcc();
   // "from_hr" is being cleared; remove any entries from it.
   void clear_incoming_entry(HeapRegion* from_hr);
   void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
   // Declare the heap size (in # of regions) to the OtherRegionsTable.
   // (Uses it to initialize from_card_cache).
   static void init_from_card_cache(size_t max_regions);
   // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
   // Make sure any entries for higher regions are invalid.
   static void shrink_from_card_cache(size_t new_n_regs);
   static void print_from_card_cache();
 };
 class HeapRegionRemSet : public CHeapObj<mtGC> {
   friend class VMStructs;
   friend class HeapRegionRemSetIterator;
 public:
   enum Event {
     Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd
   };
 private:
   G1BlockOffsetSharedArray* _bosa;
   G1BlockOffsetSharedArray* bosa() const { return _bosa; }
   OtherRegionsTable _other_regions;
   enum ParIterState { Unclaimed, Claimed, Complete };
   volatile ParIterState _iter_state;
   volatile jlong _iter_claimed;
   // Unused unless G1RecordHRRSOops is true.
   static const int MaxRecorded = 1000000;
   static OopOrNarrowOopStar* _recorded_oops;
   static HeapWord**          _recorded_cards;
   static HeapRegion**        _recorded_regions;
   static int                 _n_recorded;
   static const int MaxRecordedEvents = 1000;
   static Event*       _recorded_events;
   static int*         _recorded_event_index;
   static int          _n_recorded_events;
   static void print_event(outputStream* str, Event evnt);
 public:
   HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
                    HeapRegion* hr);
   static int num_par_rem_sets();
   static void setup_remset_size();
   HeapRegion* hr() const {
     return _other_regions.hr();
   }
   size_t occupied() const {
     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, int tid) {
     _other_regions.add_reference(from, tid);
   }
   // Removes any entries shown by the given bitmaps to contain only dead
   // objects.
   void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
   // The region is being reclaimed; clear its remset, and any mention of
   // entries for this region in other remsets.
   void clear();
   // Attempt to claim the region.  Returns true iff this call caused an
   // atomic transition from Unclaimed to Claimed.
   bool claim_iter();
   // Sets the iteration state to "complete".
   void set_iter_complete();
   // Returns "true" iff the region's iteration is complete.
   bool iter_is_complete();
   // Support for claiming blocks of cards during iteration
   size_t iter_claimed() const { return (size_t)_iter_claimed; }
   // Claim the next block of cards
   size_t iter_claimed_next(size_t step) {
     size_t current, next;
     do {
       current = iter_claimed();
       next = current + step;
     } while (Atomic::cmpxchg((jlong)next, &_iter_claimed, (jlong)current) != (jlong)current);
     return current;
   }
   void reset_for_par_iteration();
   bool verify_ready_for_par_iteration() {
     return (_iter_state == Unclaimed) && (_iter_claimed == 0);
   }
   // Initialize the given iterator to iterate over this rem set.
   void init_iterator(HeapRegionRemSetIterator* iter) const;
   // The actual # of bytes this hr_remset takes up.
   size_t mem_size() {
     return _other_regions.mem_size()
       // This correction is necessary because the above includes the second
       // part.
       + sizeof(this) - sizeof(OtherRegionsTable);
   }
   // Returns the memory occupancy of all static data structures associated
   // with remembered sets.
   static size_t static_mem_size() {
     return OtherRegionsTable::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);
   }
   void print() const;
   // Called during a stop-world phase to perform any deferred cleanups.
   static void cleanup();
   // Declare the heap size (in # of regions) to the HeapRegionRemSet(s).
   // (Uses it to initialize from_card_cache).
   static void init_heap(uint max_regions) {
     OtherRegionsTable::init_from_card_cache((size_t) max_regions);
   }
   // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
   static void shrink_heap(uint new_n_regs) {
     OtherRegionsTable::shrink_from_card_cache((size_t) new_n_regs);
   }
 #ifndef PRODUCT
   static void print_from_card_cache() {
     OtherRegionsTable::print_from_card_cache();
   }
 #endif
   static void record(HeapRegion* hr, OopOrNarrowOopStar f);
   static void print_recorded();
   static void record_event(Event evnt);
   // 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 CHeapObj<mtGC> {
   // The region over which we're iterating.
   const HeapRegionRemSet* _hrrs;
   // Local caching of HRRS fields.
   const BitMap*             _coarse_map;
   PerRegionTable**          _fine_grain_regions;
   G1BlockOffsetSharedArray* _bosa;
   G1CollectedHeap*          _g1h;
   // The number yielded since initialization.
   size_t _n_yielded_fine;
   size_t _n_yielded_coarse;
   size_t _n_yielded_sparse;
   // If true we're iterating over the coarse table; if false the fine
   // table.
   enum IterState {
     Sparse,
     Fine,
     Coarse
   };
   IterState _is;
   // In both kinds of iteration, heap offset of first card of current
   // region.
   size_t _cur_region_card_offset;
   // Card offset within cur region.
   size_t _cur_region_cur_card;
   // Coarse table iteration fields:
   // Current region index;
   int    _coarse_cur_region_index;
   size_t _coarse_cur_region_cur_card;
   bool coarse_has_next(size_t& card_index);
   // Fine table iteration fields:
   // Index of bucket-list we're working on.
   int _fine_array_index;
   // Per Region Table we're doing within current bucket list.
   PerRegionTable* _fine_cur_prt;
   /* SparsePRT::*/ SparsePRTIter _sparse_iter;
   void fine_find_next_non_null_prt();
   bool fine_has_next();
   bool fine_has_next(size_t& card_index);
 public:
   // We require an iterator to be initialized before use, so the
   // constructor does little.
   HeapRegionRemSetIterator();
   void initialize(const 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_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp@8a5ea0a9ccc4 (annotated)

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