jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp@37f87013dfd8 (annotated)

src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp@37f87013dfd8 (annotated)

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

Thu, 05 Jun 2008 15:57:56 -0700

author: ysr
date: Thu, 05 Jun 2008 15:57:56 -0700
changeset 777: 37f87013dfd8
child 924: 2494ab195856
permissions: -rw-r--r--

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

 /*
  * 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.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_heapRegionRemSet.cpp.incl"
 #define HRRS_VERBOSE 0
 #define PRT_COUNT_OCCUPIED 1
 // OtherRegionsTable
 class PerRegionTable: public CHeapObj {
   friend class OtherRegionsTable;
   friend class HeapRegionRemSetIterator;
   HeapRegion*     _hr;
   BitMap          _bm;
 #if PRT_COUNT_OCCUPIED
   jint            _occupied;
 #endif
   PerRegionTable* _next_free;
   PerRegionTable* next_free() { return _next_free; }
   void set_next_free(PerRegionTable* prt) { _next_free = prt; }
   static PerRegionTable* _free_list;
 #ifdef _MSC_VER
   // For some reason even though the classes are marked as friend they are unable
   // to access CardsPerRegion when private/protected. Only the windows c++ compiler
   // says this Sun CC and linux gcc don't have a problem with access when private
   public:
 #endif // _MSC_VER
   enum SomePrivateConstants {
     CardsPerRegion = HeapRegion::GrainBytes >> CardTableModRefBS::card_shift
   };
 protected:
   // We need access in order to union things into the base table.
   BitMap* bm() { return &_bm; }
   void recount_occupied() {
     _occupied = (jint) bm()->count_one_bits();
   }
   PerRegionTable(HeapRegion* hr) :
     _hr(hr),
 #if PRT_COUNT_OCCUPIED
     _occupied(0),
 #endif
     _bm(CardsPerRegion, false /* in-resource-area */)
   {}
   static void free(PerRegionTable* prt) {
     while (true) {
       PerRegionTable* fl = _free_list;
       prt->set_next_free(fl);
       PerRegionTable* res =
         (PerRegionTable*)
         Atomic::cmpxchg_ptr(prt, &_free_list, fl);
       if (res == fl) return;
     }
     ShouldNotReachHere();
   }
   static PerRegionTable* alloc(HeapRegion* hr) {
     PerRegionTable* fl = _free_list;
     while (fl != NULL) {
       PerRegionTable* nxt = fl->next_free();
       PerRegionTable* res =
         (PerRegionTable*)
         Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
       if (res == fl) {
         fl->init(hr);
         return fl;
       } else {
         fl = _free_list;
       }
     }
     assert(fl == NULL, "Loop condition.");
     return new PerRegionTable(hr);
   }
   void add_card_work(short from_card, bool par) {
     if (!_bm.at(from_card)) {
       if (par) {
         if (_bm.par_at_put(from_card, 1)) {
 #if PRT_COUNT_OCCUPIED
           Atomic::inc(&_occupied);
 #endif
         }
       } else {
         _bm.at_put(from_card, 1);
 #if PRT_COUNT_OCCUPIED
         _occupied++;
 #endif
       }
     }
   }
   void add_reference_work(oop* from, bool par) {
     // Must make this robust in case "from" is not in "_hr", because of
     // concurrency.
 #if HRRS_VERBOSE
     gclog_or_tty->print_cr("    PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
                            from, *from);
 #endif
     HeapRegion* loc_hr = hr();
     // If the test below fails, then this table was reused concurrently
     // with this operation.  This is OK, since the old table was coarsened,
     // and adding a bit to the new table is never incorrect.
     if (loc_hr->is_in_reserved(from)) {
       size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
       size_t from_card =
         hw_offset >>
         (CardTableModRefBS::card_shift - LogHeapWordSize);
       add_card_work((short) from_card, par);
     }
   }
 public:
   HeapRegion* hr() const { return _hr; }
 #if PRT_COUNT_OCCUPIED
   jint occupied() const {
     // Overkill, but if we ever need it...
     // guarantee(_occupied == _bm.count_one_bits(), "Check");
     return _occupied;
   }
 #else
   jint occupied() const {
     return _bm.count_one_bits();
   }
 #endif
   void init(HeapRegion* hr) {
     _hr = hr;
 #if PRT_COUNT_OCCUPIED
     _occupied = 0;
 #endif
     _bm.clear();
   }
   void add_reference(oop* from) {
     add_reference_work(from, /*parallel*/ true);
   }
   void seq_add_reference(oop* from) {
     add_reference_work(from, /*parallel*/ false);
   }
   void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
     HeapWord* hr_bot = hr()->bottom();
     int hr_first_card_index = ctbs->index_for(hr_bot);
     bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
 #if PRT_COUNT_OCCUPIED
     recount_occupied();
 #endif
   }
   void add_card(short from_card_index) {
     add_card_work(from_card_index, /*parallel*/ true);
   }
   void seq_add_card(short from_card_index) {
     add_card_work(from_card_index, /*parallel*/ false);
   }
   // (Destructively) union the bitmap of the current table into the given
   // bitmap (which is assumed to be of the same size.)
   void union_bitmap_into(BitMap* bm) {
     bm->set_union(_bm);
   }
   // Mem size in bytes.
   size_t mem_size() const {
     return sizeof(this) + _bm.size_in_words() * HeapWordSize;
   }
   static size_t fl_mem_size() {
     PerRegionTable* cur = _free_list;
     size_t res = 0;
     while (cur != NULL) {
       res += sizeof(PerRegionTable);
       cur = cur->next_free();
     }
     return res;
   }
   // Requires "from" to be in "hr()".
   bool contains_reference(oop* from) const {
     assert(hr()->is_in_reserved(from), "Precondition.");
     size_t card_ind = pointer_delta(from, hr()->bottom(),
                                     CardTableModRefBS::card_size);
     return _bm.at(card_ind);
   }
 };
 PerRegionTable* PerRegionTable::_free_list = NULL;
 #define COUNT_PAR_EXPANDS 0
 #if COUNT_PAR_EXPANDS
 static jint n_par_expands = 0;
 static jint n_par_contracts = 0;
 static jint par_expand_list_len = 0;
 static jint max_par_expand_list_len = 0;
 static void print_par_expand() {
   Atomic::inc(&n_par_expands);
   Atomic::inc(&par_expand_list_len);
   if (par_expand_list_len > max_par_expand_list_len) {
     max_par_expand_list_len = par_expand_list_len;
   }
   if ((n_par_expands % 10) == 0) {
     gclog_or_tty->print_cr("\n\n%d par expands: %d contracts, "
                   "len = %d, max_len = %d\n.",
                   n_par_expands, n_par_contracts, par_expand_list_len,
                   max_par_expand_list_len);
   }
 }
 #endif
 class PosParPRT: public PerRegionTable {
   PerRegionTable** _par_tables;
   enum SomePrivateConstants {
     ReserveParTableExpansion = 1
   };
   void par_expand() {
     int n = HeapRegionRemSet::num_par_rem_sets()-1;
     if (n <= 0) return;
     if (_par_tables == NULL) {
       PerRegionTable* res =
         (PerRegionTable*)
         Atomic::cmpxchg_ptr((PerRegionTable*)ReserveParTableExpansion,
                             &_par_tables, NULL);
       if (res != NULL) return;
       // Otherwise, we reserved the right to do the expansion.
       PerRegionTable** ptables = NEW_C_HEAP_ARRAY(PerRegionTable*, n);
       for (int i = 0; i < n; i++) {
         PerRegionTable* ptable = PerRegionTable::alloc(hr());
         ptables[i] = ptable;
       }
       // Here we do not need an atomic.
       _par_tables = ptables;
 #if COUNT_PAR_EXPANDS
       print_par_expand();
 #endif
       // We must put this table on the expanded list.
       PosParPRT* exp_head = _par_expanded_list;
       while (true) {
         set_next_par_expanded(exp_head);
         PosParPRT* res =
           (PosParPRT*)
           Atomic::cmpxchg_ptr(this, &_par_expanded_list, exp_head);
         if (res == exp_head) return;
         // Otherwise.
         exp_head = res;
       }
       ShouldNotReachHere();
     }
   }
   void par_contract() {
     assert(_par_tables != NULL, "Precondition.");
     int n = HeapRegionRemSet::num_par_rem_sets()-1;
     for (int i = 0; i < n; i++) {
       _par_tables[i]->union_bitmap_into(bm());
       PerRegionTable::free(_par_tables[i]);
       _par_tables[i] = NULL;
     }
 #if PRT_COUNT_OCCUPIED
     // We must recount the "occupied."
     recount_occupied();
 #endif
     FREE_C_HEAP_ARRAY(PerRegionTable*, _par_tables);
     _par_tables = NULL;
 #if COUNT_PAR_EXPANDS
     Atomic::inc(&n_par_contracts);
     Atomic::dec(&par_expand_list_len);
 #endif
   }
   static PerRegionTable** _par_table_fl;
   PosParPRT* _next;
   static PosParPRT* _free_list;
   PerRegionTable** par_tables() const {
     assert(uintptr_t(NULL) == 0, "Assumption.");
     if (uintptr_t(_par_tables) <= ReserveParTableExpansion)
       return NULL;
     else
       return _par_tables;
   }
   PosParPRT* _next_par_expanded;
   PosParPRT* next_par_expanded() { return _next_par_expanded; }
   void set_next_par_expanded(PosParPRT* ppprt) { _next_par_expanded = ppprt; }
   static PosParPRT* _par_expanded_list;
 public:
   PosParPRT(HeapRegion* hr) : PerRegionTable(hr), _par_tables(NULL) {}
   jint occupied() const {
     jint res = PerRegionTable::occupied();
     if (par_tables() != NULL) {
       for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
         res += par_tables()[i]->occupied();
       }
     }
     return res;
   }
   void init(HeapRegion* hr) {
     PerRegionTable::init(hr);
     _next = NULL;
     if (par_tables() != NULL) {
       for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
         par_tables()[i]->init(hr);
       }
     }
   }
   static void free(PosParPRT* prt) {
     while (true) {
       PosParPRT* fl = _free_list;
       prt->set_next(fl);
       PosParPRT* res =
         (PosParPRT*)
         Atomic::cmpxchg_ptr(prt, &_free_list, fl);
       if (res == fl) return;
     }
     ShouldNotReachHere();
   }
   static PosParPRT* alloc(HeapRegion* hr) {
     PosParPRT* fl = _free_list;
     while (fl != NULL) {
       PosParPRT* nxt = fl->next();
       PosParPRT* res =
         (PosParPRT*)
         Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
       if (res == fl) {
         fl->init(hr);
         return fl;
       } else {
         fl = _free_list;
       }
     }
     assert(fl == NULL, "Loop condition.");
     return new PosParPRT(hr);
   }
   PosParPRT* next() const { return _next; }
   void set_next(PosParPRT* nxt) { _next = nxt; }
   PosParPRT** next_addr() { return &_next; }
   void add_reference(oop* from, int tid) {
     // Expand if necessary.
     PerRegionTable** pt = par_tables();
     if (par_tables() == NULL && tid > 0 && hr()->is_gc_alloc_region()) {
       par_expand();
       pt = par_tables();
     }
     if (pt != NULL) {
       // We always have to assume that mods to table 0 are in parallel,
       // because of the claiming scheme in parallel expansion.  A thread
       // with tid != 0 that finds the table to be NULL, but doesn't succeed
       // in claiming the right of expanding it, will end up in the else
       // clause of the above if test.  That thread could be delayed, and a
       // thread 0 add reference could see the table expanded, and come
       // here.  Both threads would be adding in parallel.  But we get to
       // not use atomics for tids > 0.
       if (tid == 0) {
         PerRegionTable::add_reference(from);
       } else {
         pt[tid-1]->seq_add_reference(from);
       }
     } else {
       // Not expanded -- add to the base table.
       PerRegionTable::add_reference(from);
     }
   }
   void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
     assert(_par_tables == NULL, "Precondition");
     PerRegionTable::scrub(ctbs, card_bm);
   }
   size_t mem_size() const {
     size_t res =
       PerRegionTable::mem_size() + sizeof(this) - sizeof(PerRegionTable);
     if (_par_tables != NULL) {
       for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
         res += _par_tables[i]->mem_size();
       }
     }
     return res;
   }
   static size_t fl_mem_size() {
     PosParPRT* cur = _free_list;
     size_t res = 0;
     while (cur != NULL) {
       res += sizeof(PosParPRT);
       cur = cur->next();
     }
     return res;
   }
   bool contains_reference(oop* from) const {
     if (PerRegionTable::contains_reference(from)) return true;
     if (_par_tables != NULL) {
       for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets()-1; i++) {
         if (_par_tables[i]->contains_reference(from)) return true;
       }
     }
     return false;
   }
   static void par_contract_all();
 };
 void PosParPRT::par_contract_all() {
   PosParPRT* hd = _par_expanded_list;
   while (hd != NULL) {
     PosParPRT* nxt = hd->next_par_expanded();
     PosParPRT* res =
       (PosParPRT*)
       Atomic::cmpxchg_ptr(nxt, &_par_expanded_list, hd);
     if (res == hd) {
       // We claimed the right to contract this table.
       hd->set_next_par_expanded(NULL);
       hd->par_contract();
       hd = _par_expanded_list;
     } else {
       hd = res;
     }
   }
 }
 PosParPRT* PosParPRT::_free_list = NULL;
 PosParPRT* PosParPRT::_par_expanded_list = NULL;
 jint OtherRegionsTable::_cache_probes = 0;
 jint OtherRegionsTable::_cache_hits = 0;
 size_t OtherRegionsTable::_max_fine_entries = 0;
 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
 #if SAMPLE_FOR_EVICTION
 size_t OtherRegionsTable::_fine_eviction_stride = 0;
 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
 #endif
 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr) :
   _g1h(G1CollectedHeap::heap()),
   _m(Mutex::leaf, "An OtherRegionsTable lock", true),
   _hr(hr),
   _coarse_map(G1CollectedHeap::heap()->max_regions(),
               false /* in-resource-area */),
   _fine_grain_regions(NULL),
   _n_fine_entries(0), _n_coarse_entries(0),
 #if SAMPLE_FOR_EVICTION
   _fine_eviction_start(0),
 #endif
   _sparse_table(hr)
 {
   typedef PosParPRT* PosParPRTPtr;
   if (_max_fine_entries == 0) {
     assert(_mod_max_fine_entries_mask == 0, "Both or none.");
     _max_fine_entries = (1 << G1LogRSRegionEntries);
     _mod_max_fine_entries_mask = _max_fine_entries - 1;
 #if SAMPLE_FOR_EVICTION
     assert(_fine_eviction_sample_size == 0
            && _fine_eviction_stride == 0, "All init at same time.");
     _fine_eviction_sample_size = MAX2((size_t)4, (size_t)G1LogRSRegionEntries);
     _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
 #endif
   }
   _fine_grain_regions = new PosParPRTPtr[_max_fine_entries];
   if (_fine_grain_regions == NULL)
     vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries,
                           "Failed to allocate _fine_grain_entries.");
   for (size_t i = 0; i < _max_fine_entries; i++) {
     _fine_grain_regions[i] = NULL;
   }
 }
 int** OtherRegionsTable::_from_card_cache = NULL;
 size_t OtherRegionsTable::_from_card_cache_max_regions = 0;
 size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
 void OtherRegionsTable::init_from_card_cache(size_t max_regions) {
   _from_card_cache_max_regions = max_regions;
   int n_par_rs = HeapRegionRemSet::num_par_rem_sets();
   _from_card_cache = NEW_C_HEAP_ARRAY(int*, n_par_rs);
   for (int i = 0; i < n_par_rs; i++) {
     _from_card_cache[i] = NEW_C_HEAP_ARRAY(int, max_regions);
     for (size_t j = 0; j < max_regions; j++) {
       _from_card_cache[i][j] = -1;  // An invalid value.
     }
   }
   _from_card_cache_mem_size = n_par_rs * max_regions * sizeof(int);
 }
 void OtherRegionsTable::shrink_from_card_cache(size_t new_n_regs) {
   for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
     assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
     for (size_t j = new_n_regs; j < _from_card_cache_max_regions; j++) {
       _from_card_cache[i][j] = -1;  // An invalid value.
     }
   }
 }
 #ifndef PRODUCT
 void OtherRegionsTable::print_from_card_cache() {
   for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
     for (size_t j = 0; j < _from_card_cache_max_regions; j++) {
       gclog_or_tty->print_cr("_from_card_cache[%d][%d] = %d.",
                     i, j, _from_card_cache[i][j]);
     }
   }
 }
 #endif
 void OtherRegionsTable::add_reference(oop* from, int tid) {
   size_t cur_hrs_ind = hr()->hrs_index();
 #if HRRS_VERBOSE
   gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
                                                   from, *from);
 #endif
   int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
 #if HRRS_VERBOSE
   gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
                 hr()->bottom(), from_card,
                 _from_card_cache[tid][cur_hrs_ind]);
 #endif
 #define COUNT_CACHE 0
 #if COUNT_CACHE
   jint p = Atomic::add(1, &_cache_probes);
   if ((p % 10000) == 0) {
     jint hits = _cache_hits;
     gclog_or_tty->print_cr("%d/%d = %5.2f%% RS cache hits.",
                   _cache_hits, p, 100.0* (float)hits/(float)p);
   }
 #endif
   if (from_card == _from_card_cache[tid][cur_hrs_ind]) {
 #if HRRS_VERBOSE
     gclog_or_tty->print_cr("  from-card cache hit.");
 #endif
 #if COUNT_CACHE
     Atomic::inc(&_cache_hits);
 #endif
     assert(contains_reference(from), "We just added it!");
     return;
   } else {
     _from_card_cache[tid][cur_hrs_ind] = from_card;
   }
   // Note that this may be a continued H region.
   HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
   size_t from_hrs_ind = (size_t)from_hr->hrs_index();
   // If the region is already coarsened, return.
   if (_coarse_map.at(from_hrs_ind)) {
 #if HRRS_VERBOSE
     gclog_or_tty->print_cr("  coarse map hit.");
 #endif
     assert(contains_reference(from), "We just added it!");
     return;
   }
   // Otherwise find a per-region table to add it to.
   size_t ind = from_hrs_ind & _mod_max_fine_entries_mask;
   PosParPRT* prt = find_region_table(ind, from_hr);
   if (prt == NULL) {
     MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
     // Confirm that it's really not there...
     prt = find_region_table(ind, from_hr);
     if (prt == NULL) {
       uintptr_t from_hr_bot_card_index =
         uintptr_t(from_hr->bottom())
           >> CardTableModRefBS::card_shift;
       int card_index = from_card - from_hr_bot_card_index;
       assert(0 <= card_index && card_index < PosParPRT::CardsPerRegion,
              "Must be in range.");
       if (G1HRRSUseSparseTable &&
           _sparse_table.add_card((short) from_hrs_ind, card_index)) {
         if (G1RecordHRRSOops) {
           HeapRegionRemSet::record(hr(), from);
 #if HRRS_VERBOSE
           gclog_or_tty->print("   Added card " PTR_FORMAT " to region "
                               "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
                               align_size_down(uintptr_t(from),
                                               CardTableModRefBS::card_size),
                               hr()->bottom(), from);
 #endif
         }
 #if HRRS_VERBOSE
         gclog_or_tty->print_cr("   added card to sparse table.");
 #endif
         assert(contains_reference_locked(from), "We just added it!");
         return;
       } else {
 #if HRRS_VERBOSE
         gclog_or_tty->print_cr("   [tid %d] sparse table entry "
                       "overflow(f: %d, t: %d)",
                       tid, from_hrs_ind, cur_hrs_ind);
 #endif
       }
       // Otherwise, transfer from sparse to fine-grain.
       short cards[SparsePRTEntry::CardsPerEntry];
       if (G1HRRSUseSparseTable) {
         bool res = _sparse_table.get_cards((short) from_hrs_ind, &cards[0]);
         assert(res, "There should have been an entry");
       }
       if (_n_fine_entries == _max_fine_entries) {
         prt = delete_region_table();
       } else {
         prt = PosParPRT::alloc(from_hr);
       }
       prt->init(from_hr);
       // Record the outgoing pointer in the from_region's outgoing bitmap.
       from_hr->rem_set()->add_outgoing_reference(hr());
       PosParPRT* first_prt = _fine_grain_regions[ind];
       prt->set_next(first_prt);  // XXX Maybe move to init?
       _fine_grain_regions[ind] = prt;
       _n_fine_entries++;
       // Add in the cards from the sparse table.
       if (G1HRRSUseSparseTable) {
         for (int i = 0; i < SparsePRTEntry::CardsPerEntry; i++) {
           short c = cards[i];
           if (c != SparsePRTEntry::NullEntry) {
             prt->add_card(c);
           }
         }
         // Now we can delete the sparse entry.
         bool res = _sparse_table.delete_entry((short) from_hrs_ind);
         assert(res, "It should have been there.");
       }
     }
     assert(prt != NULL && prt->hr() == from_hr, "consequence");
   }
   // Note that we can't assert "prt->hr() == from_hr", because of the
   // possibility of concurrent reuse.  But see head comment of
   // OtherRegionsTable for why this is OK.
   assert(prt != NULL, "Inv");
   prt->add_reference(from, tid);
   if (G1RecordHRRSOops) {
     HeapRegionRemSet::record(hr(), from);
 #if HRRS_VERBOSE
     gclog_or_tty->print("Added card " PTR_FORMAT " to region "
                         "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
                         align_size_down(uintptr_t(from),
                                         CardTableModRefBS::card_size),
                         hr()->bottom(), from);
 #endif
   }
   assert(contains_reference(from), "We just added it!");
 }
 PosParPRT*
 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
   PosParPRT* prt = _fine_grain_regions[ind];
   while (prt != NULL && prt->hr() != hr) {
     prt = prt->next();
   }
   // Loop postcondition is the method postcondition.
   return prt;
 }
 #define DRT_CENSUS 0
 #if DRT_CENSUS
 static const int HistoSize = 6;
 static int global_histo[HistoSize] = { 0, 0, 0, 0, 0, 0 };
 static int coarsenings = 0;
 static int occ_sum = 0;
 #endif
 jint OtherRegionsTable::_n_coarsenings = 0;
 PosParPRT* OtherRegionsTable::delete_region_table() {
 #if DRT_CENSUS
   int histo[HistoSize] = { 0, 0, 0, 0, 0, 0 };
   const int histo_limits[] = { 1, 4, 16, 64, 256, 2048 };
 #endif
   assert(_m.owned_by_self(), "Precondition");
   assert(_n_fine_entries == _max_fine_entries, "Precondition");
   PosParPRT* max = NULL;
   jint max_occ = 0;
   PosParPRT** max_prev;
   size_t max_ind;
 #if SAMPLE_FOR_EVICTION
   size_t i = _fine_eviction_start;
   for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
     size_t ii = i;
     // Make sure we get a non-NULL sample.
     while (_fine_grain_regions[ii] == NULL) {
       ii++;
       if (ii == _max_fine_entries) ii = 0;
       guarantee(ii != i, "We must find one.");
     }
     PosParPRT** prev = &_fine_grain_regions[ii];
     PosParPRT* cur = *prev;
     while (cur != NULL) {
       jint cur_occ = cur->occupied();
       if (max == NULL || cur_occ > max_occ) {
         max = cur;
         max_prev = prev;
         max_ind = i;
         max_occ = cur_occ;
       }
       prev = cur->next_addr();
       cur = cur->next();
     }
     i = i + _fine_eviction_stride;
     if (i >= _n_fine_entries) i = i - _n_fine_entries;
   }
   _fine_eviction_start++;
   if (_fine_eviction_start >= _n_fine_entries)
     _fine_eviction_start -= _n_fine_entries;
 #else
   for (int i = 0; i < _max_fine_entries; i++) {
     PosParPRT** prev = &_fine_grain_regions[i];
     PosParPRT* cur = *prev;
     while (cur != NULL) {
       jint cur_occ = cur->occupied();
 #if DRT_CENSUS
       for (int k = 0; k < HistoSize; k++) {
         if (cur_occ <= histo_limits[k]) {
           histo[k]++; global_histo[k]++; break;
         }
       }
 #endif
       if (max == NULL || cur_occ > max_occ) {
         max = cur;
         max_prev = prev;
         max_ind = i;
         max_occ = cur_occ;
       }
       prev = cur->next_addr();
       cur = cur->next();
     }
   }
 #endif
   // XXX
   guarantee(max != NULL, "Since _n_fine_entries > 0");
 #if DRT_CENSUS
   gclog_or_tty->print_cr("In a coarsening: histo of occs:");
   for (int k = 0; k < HistoSize; k++) {
     gclog_or_tty->print_cr("  <= %4d: %5d.", histo_limits[k], histo[k]);
   }
   coarsenings++;
   occ_sum += max_occ;
   if ((coarsenings % 100) == 0) {
     gclog_or_tty->print_cr("\ncoarsenings = %d; global summary:", coarsenings);
     for (int k = 0; k < HistoSize; k++) {
       gclog_or_tty->print_cr("  <= %4d: %5d.", histo_limits[k], global_histo[k]);
     }
     gclog_or_tty->print_cr("Avg occ of deleted region = %6.2f.",
                   (float)occ_sum/(float)coarsenings);
   }
 #endif
   // Set the corresponding coarse bit.
   int max_hrs_index = max->hr()->hrs_index();
   if (!_coarse_map.at(max_hrs_index)) {
     _coarse_map.at_put(max_hrs_index, true);
     _n_coarse_entries++;
 #if 0
     gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
                "for region [" PTR_FORMAT "...] (%d coarse entries).\n",
                hr()->bottom(),
                max->hr()->bottom(),
                _n_coarse_entries);
 #endif
   }
   // Unsplice.
   *max_prev = max->next();
   Atomic::inc(&_n_coarsenings);
   _n_fine_entries--;
   return max;
 }
 // At present, this must be called stop-world single-threaded.
 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
                               BitMap* region_bm, BitMap* card_bm) {
   // First eliminated garbage regions from the coarse map.
   if (G1RSScrubVerbose)
     gclog_or_tty->print_cr("Scrubbing region %d:", hr()->hrs_index());
   assert(_coarse_map.size() == region_bm->size(), "Precondition");
   if (G1RSScrubVerbose)
     gclog_or_tty->print("   Coarse map: before = %d...", _n_coarse_entries);
   _coarse_map.set_intersection(*region_bm);
   _n_coarse_entries = _coarse_map.count_one_bits();
   if (G1RSScrubVerbose)
     gclog_or_tty->print_cr("   after = %d.", _n_coarse_entries);
   // Now do the fine-grained maps.
   for (size_t i = 0; i < _max_fine_entries; i++) {
     PosParPRT* cur = _fine_grain_regions[i];
     PosParPRT** prev = &_fine_grain_regions[i];
     while (cur != NULL) {
       PosParPRT* nxt = cur->next();
       // If the entire region is dead, eliminate.
       if (G1RSScrubVerbose)
         gclog_or_tty->print_cr("     For other region %d:", cur->hr()->hrs_index());
       if (!region_bm->at(cur->hr()->hrs_index())) {
         *prev = nxt;
         cur->set_next(NULL);
         _n_fine_entries--;
         if (G1RSScrubVerbose)
           gclog_or_tty->print_cr("          deleted via region map.");
         PosParPRT::free(cur);
       } else {
         // Do fine-grain elimination.
         if (G1RSScrubVerbose)
           gclog_or_tty->print("          occ: before = %4d.", cur->occupied());
         cur->scrub(ctbs, card_bm);
         if (G1RSScrubVerbose)
           gclog_or_tty->print_cr("          after = %4d.", cur->occupied());
         // Did that empty the table completely?
         if (cur->occupied() == 0) {
           *prev = nxt;
           cur->set_next(NULL);
           _n_fine_entries--;
           PosParPRT::free(cur);
         } else {
           prev = cur->next_addr();
         }
       }
       cur = nxt;
     }
   }
   // Since we may have deleted a from_card_cache entry from the RS, clear
   // the FCC.
   clear_fcc();
 }
 size_t OtherRegionsTable::occupied() const {
   // Cast away const in this case.
   MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
   size_t sum = occ_fine();
   sum += occ_sparse();
   sum += occ_coarse();
   return sum;
 }
 size_t OtherRegionsTable::occ_fine() const {
   size_t sum = 0;
   for (size_t i = 0; i < _max_fine_entries; i++) {
     PosParPRT* cur = _fine_grain_regions[i];
     while (cur != NULL) {
       sum += cur->occupied();
       cur = cur->next();
     }
   }
   return sum;
 }
 size_t OtherRegionsTable::occ_coarse() const {
   return (_n_coarse_entries * PosParPRT::CardsPerRegion);
 }
 size_t OtherRegionsTable::occ_sparse() const {
   return _sparse_table.occupied();
 }
 size_t OtherRegionsTable::mem_size() const {
   // Cast away const in this case.
   MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
   size_t sum = 0;
   for (size_t i = 0; i < _max_fine_entries; i++) {
     PosParPRT* cur = _fine_grain_regions[i];
     while (cur != NULL) {
       sum += cur->mem_size();
       cur = cur->next();
     }
   }
   sum += (sizeof(PosParPRT*) * _max_fine_entries);
   sum += (_coarse_map.size_in_words() * HeapWordSize);
   sum += (_sparse_table.mem_size());
   sum += sizeof(*this) - sizeof(_sparse_table); // Avoid double counting above.
   return sum;
 }
 size_t OtherRegionsTable::static_mem_size() {
   return _from_card_cache_mem_size;
 }
 size_t OtherRegionsTable::fl_mem_size() {
   return PerRegionTable::fl_mem_size() + PosParPRT::fl_mem_size();
 }
 void OtherRegionsTable::clear_fcc() {
   for (int i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
     _from_card_cache[i][hr()->hrs_index()] = -1;
   }
 }
 void OtherRegionsTable::clear() {
   MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
   for (size_t i = 0; i < _max_fine_entries; i++) {
     PosParPRT* cur = _fine_grain_regions[i];
     while (cur != NULL) {
       PosParPRT* nxt = cur->next();
       PosParPRT::free(cur);
       cur = nxt;
     }
     _fine_grain_regions[i] = NULL;
   }
   _sparse_table.clear();
   _coarse_map.clear();
   _n_fine_entries = 0;
   _n_coarse_entries = 0;
   clear_fcc();
 }
 void OtherRegionsTable::clear_incoming_entry(HeapRegion* from_hr) {
   MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
   size_t hrs_ind = (size_t)from_hr->hrs_index();
   size_t ind = hrs_ind & _mod_max_fine_entries_mask;
   if (del_single_region_table(ind, from_hr)) {
     assert(!_coarse_map.at(hrs_ind), "Inv");
   } else {
     _coarse_map.par_at_put(hrs_ind, 0);
   }
   // Check to see if any of the fcc entries come from here.
   int hr_ind = hr()->hrs_index();
   for (int tid = 0; tid < HeapRegionRemSet::num_par_rem_sets(); tid++) {
     int fcc_ent = _from_card_cache[tid][hr_ind];
     if (fcc_ent != -1) {
       HeapWord* card_addr = (HeapWord*)
         (uintptr_t(fcc_ent) << CardTableModRefBS::card_shift);
       if (hr()->is_in_reserved(card_addr)) {
         // Clear the from card cache.
         _from_card_cache[tid][hr_ind] = -1;
       }
     }
   }
 }
 bool OtherRegionsTable::del_single_region_table(size_t ind,
                                                 HeapRegion* hr) {
   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
   PosParPRT** prev_addr = &_fine_grain_regions[ind];
   PosParPRT* prt = *prev_addr;
   while (prt != NULL && prt->hr() != hr) {
     prev_addr = prt->next_addr();
     prt = prt->next();
   }
   if (prt != NULL) {
     assert(prt->hr() == hr, "Loop postcondition.");
     *prev_addr = prt->next();
     PosParPRT::free(prt);
     _n_fine_entries--;
     return true;
   } else {
     return false;
   }
 }
 bool OtherRegionsTable::contains_reference(oop* from) const {
   // Cast away const in this case.
   MutexLockerEx x((Mutex*)&_m, Mutex::_no_safepoint_check_flag);
   return contains_reference_locked(from);
 }
 bool OtherRegionsTable::contains_reference_locked(oop* from) const {
   HeapRegion* hr = _g1h->heap_region_containing_raw(from);
   if (hr == NULL) return false;
   size_t hr_ind = hr->hrs_index();
   // Is this region in the coarse map?
   if (_coarse_map.at(hr_ind)) return true;
   PosParPRT* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
                                      hr);
   if (prt != NULL) {
     return prt->contains_reference(from);
   } else {
     uintptr_t from_card =
       (uintptr_t(from) >> CardTableModRefBS::card_shift);
     uintptr_t hr_bot_card_index =
       uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
     assert(from_card >= hr_bot_card_index, "Inv");
     int card_index = from_card - hr_bot_card_index;
     return _sparse_table.contains_card((short)hr_ind, card_index);
   }
 }
 bool HeapRegionRemSet::_par_traversal = false;
 void HeapRegionRemSet::set_par_traversal(bool b) {
   assert(_par_traversal != b, "Proper alternation...");
   _par_traversal = b;
 }
 int HeapRegionRemSet::num_par_rem_sets() {
   // We always have at least two, so that a mutator thread can claim an
   // id and add to a rem set.
   return (int) MAX2(ParallelGCThreads, (size_t)2);
 }
 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
                                    HeapRegion* hr)
     : _bosa(bosa), _other_regions(hr),
       _outgoing_region_map(G1CollectedHeap::heap()->max_regions(),
                            false /* in-resource-area */),
       _iter_state(Unclaimed)
 {}
 void HeapRegionRemSet::init_for_par_iteration() {
   _iter_state = Unclaimed;
 }
 bool HeapRegionRemSet::claim_iter() {
   if (_iter_state != Unclaimed) return false;
   jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
   return (res == Unclaimed);
 }
 void HeapRegionRemSet::set_iter_complete() {
   _iter_state = Complete;
 }
 bool HeapRegionRemSet::iter_is_complete() {
   return _iter_state == Complete;
 }
 void HeapRegionRemSet::init_iterator(HeapRegionRemSetIterator* iter) const {
   iter->initialize(this);
 }
 #ifndef PRODUCT
 void HeapRegionRemSet::print() const {
   HeapRegionRemSetIterator iter;
   init_iterator(&iter);
   size_t card_index;
   while (iter.has_next(card_index)) {
     HeapWord* card_start =
       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
     gclog_or_tty->print_cr("  Card " PTR_FORMAT ".", card_start);
   }
   // XXX
   if (iter.n_yielded() != occupied()) {
     gclog_or_tty->print_cr("Yielded disagrees with occupied:");
     gclog_or_tty->print_cr("  %6d yielded (%6d coarse, %6d fine).",
                   iter.n_yielded(),
                   iter.n_yielded_coarse(), iter.n_yielded_fine());
     gclog_or_tty->print_cr("  %6d occ     (%6d coarse, %6d fine).",
                   occupied(), occ_coarse(), occ_fine());
   }
   guarantee(iter.n_yielded() == occupied(),
             "We should have yielded all the represented cards.");
 }
 #endif
 void HeapRegionRemSet::cleanup() {
   SparsePRT::cleanup_all();
 }
 void HeapRegionRemSet::par_cleanup() {
   PosParPRT::par_contract_all();
 }
 void HeapRegionRemSet::add_outgoing_reference(HeapRegion* to_hr) {
   _outgoing_region_map.par_at_put(to_hr->hrs_index(), 1);
 }
 void HeapRegionRemSet::clear() {
   clear_outgoing_entries();
   _outgoing_region_map.clear();
   _other_regions.clear();
   assert(occupied() == 0, "Should be clear.");
 }
 void HeapRegionRemSet::clear_outgoing_entries() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   size_t i = _outgoing_region_map.get_next_one_offset(0);
   while (i < _outgoing_region_map.size()) {
     HeapRegion* to_region = g1h->region_at(i);
     to_region->rem_set()->clear_incoming_entry(hr());
     i = _outgoing_region_map.get_next_one_offset(i+1);
   }
 }
 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
                              BitMap* region_bm, BitMap* card_bm) {
   _other_regions.scrub(ctbs, region_bm, card_bm);
 }
 //-------------------- Iteration --------------------
 HeapRegionRemSetIterator::
 HeapRegionRemSetIterator() :
   _hrrs(NULL),
   _g1h(G1CollectedHeap::heap()),
   _bosa(NULL),
   _sparse_iter(size_t(G1CollectedHeap::heap()->reserved_region().start())
                >> CardTableModRefBS::card_shift)
 {}
 void HeapRegionRemSetIterator::initialize(const HeapRegionRemSet* hrrs) {
   _hrrs = hrrs;
   _coarse_map = &_hrrs->_other_regions._coarse_map;
   _fine_grain_regions = _hrrs->_other_regions._fine_grain_regions;
   _bosa = _hrrs->bosa();
   _is = Sparse;
   // Set these values so that we increment to the first region.
   _coarse_cur_region_index = -1;
   _coarse_cur_region_cur_card = (PosParPRT::CardsPerRegion-1);;
   _cur_region_cur_card = 0;
   _fine_array_index = -1;
   _fine_cur_prt = NULL;
   _n_yielded_coarse = 0;
   _n_yielded_fine = 0;
   _n_yielded_sparse = 0;
   _sparse_iter.init(&hrrs->_other_regions._sparse_table);
 }
 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
   if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
   // Go to the next card.
   _coarse_cur_region_cur_card++;
   // Was the last the last card in the current region?
   if (_coarse_cur_region_cur_card == PosParPRT::CardsPerRegion) {
     // Yes: find the next region.  This may leave _coarse_cur_region_index
     // Set to the last index, in which case there are no more coarse
     // regions.
     _coarse_cur_region_index =
       (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
     if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
       _coarse_cur_region_cur_card = 0;
       HeapWord* r_bot =
         _g1h->region_at(_coarse_cur_region_index)->bottom();
       _cur_region_card_offset = _bosa->index_for(r_bot);
     } else {
       return false;
     }
   }
   // If we didn't return false above, then we can yield a card.
   card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
   return true;
 }
 void HeapRegionRemSetIterator::fine_find_next_non_null_prt() {
   // Otherwise, find the next bucket list in the array.
   _fine_array_index++;
   while (_fine_array_index < (int) OtherRegionsTable::_max_fine_entries) {
     _fine_cur_prt = _fine_grain_regions[_fine_array_index];
     if (_fine_cur_prt != NULL) return;
     else _fine_array_index++;
   }
   assert(_fine_cur_prt == NULL, "Loop post");
 }
 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
   if (fine_has_next()) {
     _cur_region_cur_card =
       _fine_cur_prt->_bm.get_next_one_offset(_cur_region_cur_card + 1);
   }
   while (!fine_has_next()) {
     if (_cur_region_cur_card == PosParPRT::CardsPerRegion) {
       _cur_region_cur_card = 0;
       _fine_cur_prt = _fine_cur_prt->next();
     }
     if (_fine_cur_prt == NULL) {
       fine_find_next_non_null_prt();
       if (_fine_cur_prt == NULL) return false;
     }
     assert(_fine_cur_prt != NULL && _cur_region_cur_card == 0,
            "inv.");
     HeapWord* r_bot =
       _fine_cur_prt->hr()->bottom();
     _cur_region_card_offset = _bosa->index_for(r_bot);
     _cur_region_cur_card = _fine_cur_prt->_bm.get_next_one_offset(0);
   }
   assert(fine_has_next(), "Or else we exited the loop via the return.");
   card_index = _cur_region_card_offset + _cur_region_cur_card;
   return true;
 }
 bool HeapRegionRemSetIterator::fine_has_next() {
   return
     _fine_cur_prt != NULL &&
     _cur_region_cur_card < PosParPRT::CardsPerRegion;
 }
 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
   switch (_is) {
   case Sparse:
     if (_sparse_iter.has_next(card_index)) {
       _n_yielded_sparse++;
       return true;
     }
     // Otherwise, deliberate fall-through
     _is = Fine;
   case Fine:
     if (fine_has_next(card_index)) {
       _n_yielded_fine++;
       return true;
     }
     // Otherwise, deliberate fall-through
     _is = Coarse;
   case Coarse:
     if (coarse_has_next(card_index)) {
       _n_yielded_coarse++;
       return true;
     }
     // Otherwise...
     break;
   }
   assert(ParallelGCThreads > 1 ||
          n_yielded() == _hrrs->occupied(),
          "Should have yielded all the cards in the rem set "
          "(in the non-par case).");
   return false;
 }
 oop**        HeapRegionRemSet::_recorded_oops = NULL;
 HeapWord**   HeapRegionRemSet::_recorded_cards = NULL;
 HeapRegion** HeapRegionRemSet::_recorded_regions = NULL;
 int          HeapRegionRemSet::_n_recorded = 0;
 HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
 int*         HeapRegionRemSet::_recorded_event_index = NULL;
 int          HeapRegionRemSet::_n_recorded_events = 0;
 void HeapRegionRemSet::record(HeapRegion* hr, oop* f) {
   if (_recorded_oops == NULL) {
     assert(_n_recorded == 0
            && _recorded_cards == NULL
            && _recorded_regions == NULL,
            "Inv");
     _recorded_oops = NEW_C_HEAP_ARRAY(oop*, MaxRecorded);
     _recorded_cards = NEW_C_HEAP_ARRAY(HeapWord*, MaxRecorded);
     _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*, MaxRecorded);
   }
   if (_n_recorded == MaxRecorded) {
     gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
   } else {
     _recorded_cards[_n_recorded] =
       (HeapWord*)align_size_down(uintptr_t(f),
                                  CardTableModRefBS::card_size);
     _recorded_oops[_n_recorded] = f;
     _recorded_regions[_n_recorded] = hr;
     _n_recorded++;
   }
 }
 void HeapRegionRemSet::record_event(Event evnt) {
   if (!G1RecordHRRSEvents) return;
   if (_recorded_events == NULL) {
     assert(_n_recorded_events == 0
            && _recorded_event_index == NULL,
            "Inv");
     _recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents);
     _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents);
   }
   if (_n_recorded_events == MaxRecordedEvents) {
     gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
   } else {
     _recorded_events[_n_recorded_events] = evnt;
     _recorded_event_index[_n_recorded_events] = _n_recorded;
     _n_recorded_events++;
   }
 }
 void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
   switch (evnt) {
   case Event_EvacStart:
     str->print("Evac Start");
     break;
   case Event_EvacEnd:
     str->print("Evac End");
     break;
   case Event_RSUpdateEnd:
     str->print("RS Update End");
     break;
   }
 }
 void HeapRegionRemSet::print_recorded() {
   int cur_evnt = 0;
   Event cur_evnt_kind;
   int cur_evnt_ind = 0;
   if (_n_recorded_events > 0) {
     cur_evnt_kind = _recorded_events[cur_evnt];
     cur_evnt_ind = _recorded_event_index[cur_evnt];
   }
   for (int i = 0; i < _n_recorded; i++) {
     while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
       gclog_or_tty->print("Event: ");
       print_event(gclog_or_tty, cur_evnt_kind);
       gclog_or_tty->print_cr("");
       cur_evnt++;
       if (cur_evnt < MaxRecordedEvents) {
         cur_evnt_kind = _recorded_events[cur_evnt];
         cur_evnt_ind = _recorded_event_index[cur_evnt];
       }
     }
     gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
                         " for ref " PTR_FORMAT ".\n",
                         _recorded_cards[i], _recorded_regions[i]->bottom(),
                         _recorded_oops[i]);
   }
 }
 #ifndef PRODUCT
 void HeapRegionRemSet::test() {
   os::sleep(Thread::current(), (jlong)5000, false);
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   // Run with "-XX:G1LogRSRegionEntries=2", so that 1 and 5 end up in same
   // hash bucket.
   HeapRegion* hr0 = g1h->region_at(0);
   HeapRegion* hr1 = g1h->region_at(1);
   HeapRegion* hr2 = g1h->region_at(5);
   HeapRegion* hr3 = g1h->region_at(6);
   HeapRegion* hr4 = g1h->region_at(7);
   HeapRegion* hr5 = g1h->region_at(8);
   HeapWord* hr1_start = hr1->bottom();
   HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
   HeapWord* hr1_last = hr1->end() - 1;
   HeapWord* hr2_start = hr2->bottom();
   HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
   HeapWord* hr2_last = hr2->end() - 1;
   HeapWord* hr3_start = hr3->bottom();
   HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
   HeapWord* hr3_last = hr3->end() - 1;
   HeapRegionRemSet* hrrs = hr0->rem_set();
   // Make three references from region 0x101...
   hrrs->add_reference((oop*)hr1_start);
   hrrs->add_reference((oop*)hr1_mid);
   hrrs->add_reference((oop*)hr1_last);
   hrrs->add_reference((oop*)hr2_start);
   hrrs->add_reference((oop*)hr2_mid);
   hrrs->add_reference((oop*)hr2_last);
   hrrs->add_reference((oop*)hr3_start);
   hrrs->add_reference((oop*)hr3_mid);
   hrrs->add_reference((oop*)hr3_last);
   // Now cause a coarsening.
   hrrs->add_reference((oop*)hr4->bottom());
   hrrs->add_reference((oop*)hr5->bottom());
   // Now, does iteration yield these three?
   HeapRegionRemSetIterator iter;
   hrrs->init_iterator(&iter);
   size_t sum = 0;
   size_t card_index;
   while (iter.has_next(card_index)) {
     HeapWord* card_start =
       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
     gclog_or_tty->print_cr("  Card " PTR_FORMAT ".", card_start);
     sum++;
   }
   guarantee(sum == 11 - 3 + 2048, "Failure");
   guarantee(sum == hrrs->occupied(), "Failure");
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp@37f87013dfd8 (annotated)

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