graal-compiler: src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp comparison

comparison src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp @ 342:37f87013dfd8

6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr

author	ysr
date	Thu, 05 Jun 2008 15:57:56 -0700
parents
children	fe3d7c11b4b7

comparison

equal deleted inserted replaced

-:0b27f3512f9e
+:37f87013dfd8
+/*
+* Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+// 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 PosParPRT;
+class SparsePRT;
+// 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: public CHeapObj {
+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;
+PosParPRT** _fine_grain_regions;
+size_t      _n_fine_entries;
+#define SAMPLE_FOR_EVICTION 1
+#if SAMPLE_FOR_EVICTION
+size_t        _fine_eviction_start;
+static size_t _fine_eviction_stride;
+static size_t _fine_eviction_sample_size;
+#endif
+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".
+PosParPRT* find_region_table(size_t ind, HeapRegion* hr) const;
+// Find, delete, and return a candidate PosParPRT, 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.
+PosParPRT* 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);
+static jint _cache_probes;
+static jint _cache_hits;
+// 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;
+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(oop* from, int tid);
+void add_reference(oop* from) {
+return add_reference(from, 0);
+}
+// 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(oop* from) const;
+bool contains_reference_locked(oop* 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);
+// 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 {
+friend class VMStructs;
+friend class HeapRegionRemSetIterator;
+public:
+enum Event {
+Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd
+};
+private:
+G1BlockOffsetSharedArray* _bosa;
+G1BlockOffsetSharedArray* bosa() const { return _bosa; }
+static bool _par_traversal;
+OtherRegionsTable _other_regions;
+// One set bit for every region that has an entry for this one.
+BitMap _outgoing_region_map;
+// Clear entries for the current region in any rem sets named in
+// the _outgoing_region_map.
+void clear_outgoing_entries();
+#if MAYBE
+// Audit the given card index.
+void audit_card(size_t card_num, HeapRegion* hr, u2* rc_arr,
+HeapRegionRemSet* empty_cards, size_t* one_obj_cards);
+// Assumes that "audit_stage1" has been called for "hr", to set up
+// "shadow" and "new_rs" appropriately.  Identifies individual popular
+// objects; returns "true" if any are found.
+bool audit_find_pop(HeapRegion* hr, u2* rc_arr);
+// Assumes that "audit_stage1" has been called for "hr", to set up
+// "shadow" and "new_rs" appropriately.  Identifies individual popular
+// objects, and determines the number of entries in "new_rs" if any such
+// popular objects are ignored.  If this is sufficiently small, returns
+// "false" to indicate that a constraint should not be introduced.
+// Otherwise, returns "true" to indicate that we should go ahead with
+// adding the constraint.
+bool audit_stag(HeapRegion* hr, u2* rc_arr);
+u2* alloc_rc_array();
+SeqHeapRegionRemSet* audit_post(u2* rc_arr, size_t multi_obj_crds,
+SeqHeapRegionRemSet* empty_cards);
+#endif
+enum ParIterState { Unclaimed, Claimed, Complete };
+ParIterState _iter_state;
+// Unused unless G1RecordHRRSOops is true.
+static const int MaxRecorded = 1000000;
+static oop**        _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 bool par_traversal() { return _par_traversal; }
+static void set_par_traversal(bool b);
+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.  Returns "true" iff this addition causes
+the size limit to be reached. */
+bool add_reference(oop* from) {
+_other_regions.add_reference(from);
+return false;
+}
+/* Used in the parallel case.  Returns "true" iff this addition causes
+the size limit to be reached. */
+bool add_reference(oop* from, int tid) {
+_other_regions.add_reference(from, tid);
+return false;
+}
+// Records the fact that the current region contains an outgoing
+// reference into "to_hr".
+void add_outgoing_reference(HeapRegion* to_hr);
+// 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();
+// Forget any entries due to pointers from "from_hr".
+void clear_incoming_entry(HeapRegion* from_hr) {
+_other_regions.clear_incoming_entry(from_hr);
+}
+#if 0
+virtual void cleanup() = 0;
+#endif
+// Should be called from single-threaded code.
+void init_for_par_iteration();
+// 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();
+// Initialize the given iterator to iterate over this rem set.
+void init_iterator(HeapRegionRemSetIterator* iter) const;
+#if 0
+// Apply the "do_card" method to the start address of every card in the
+// rem set.  Returns false if some application of the closure aborted.
+virtual bool card_iterate(CardClosure* iter) = 0;
+#endif
+// 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(oop* from) const {
+return _other_regions.contains_reference(from);
+}
+void print() const;
+#if MAYBE
+// We are about to introduce a constraint, requiring the collection time
+// of the region owning this RS to be <= "hr", and forgetting pointers
+// from the owning region to "hr."  Before doing so, examines this rem
+// set for pointers to "hr", possibly identifying some popular objects.,
+// and possibly finding some cards to no longer contain pointers to "hr",
+//
+// These steps may prevent the the constraint from being necessary; in
+// which case returns a set of cards now thought to contain no pointers
+// into HR.  In the normal (I assume) case, returns NULL, indicating that
+// we should go ahead and add the constraint.
+virtual SeqHeapRegionRemSet* audit(HeapRegion* hr) = 0;
+#endif
+// Called during a stop-world phase to perform any deferred cleanups.
+// The second version may be called by parallel threads after then finish
+// collection work.
+static void cleanup();
+static void par_cleanup();
+// Declare the heap size (in # of regions) to the HeapRegionRemSet(s).
+// (Uses it to initialize from_card_cache).
+static void init_heap(size_t max_regions) {
+OtherRegionsTable::init_from_card_cache(max_regions);
+}
+// Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
+static void shrink_heap(size_t new_n_regs) {
+OtherRegionsTable::shrink_from_card_cache(new_n_regs);
+}
+#ifndef PRODUCT
+static void print_from_card_cache() {
+OtherRegionsTable::print_from_card_cache();
+}
+#endif
+static void record(HeapRegion* hr, oop* f);
+static void print_recorded();
+static void record_event(Event evnt);
+// Run unit tests.
+#ifndef PRODUCT
+static void test();
+#endif
+};
+class HeapRegionRemSetIterator : public CHeapObj {
+// The region over which we're iterating.
+const HeapRegionRemSet* _hrrs;
+// Local caching of HRRS fields.
+const BitMap*             _coarse_map;
+PosParPRT**               _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;
+int _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.
+PosParPRT* _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();
+}
+};
+#if 0
+class CardClosure: public Closure {
+public:
+virtual void do_card(HeapWord* card_start) = 0;
+};
+#endif

Mercurial > hg > graal-compiler

comparison src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp @ 342:37f87013dfd8