jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp@96b1c2e06e25 (annotated)

src/share/vm/gc_implementation/g1/heapRegionRemSet.cpp@96b1c2e06e25 (annotated)

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

Mon, 24 Mar 2014 15:30:36 +0100

author: tschatzl
date: Mon, 24 Mar 2014 15:30:36 +0100
changeset 6404: 96b1c2e06e25
parent 6403: d7070f371770
child 6407: ae7336d6337e
permissions: -rw-r--r--

8027295: Free CSet takes ~50% of young pause time
Summary: Improve fast card cache iteration and avoid taking locks when freeing the collection set.
Reviewed-by: brutisso

 /*
  * Copyright (c) 2001, 2014, 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.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/g1/concurrentG1Refine.hpp"
 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/heapRegionRemSet.hpp"
 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
 #include "memory/allocation.hpp"
 #include "memory/padded.inline.hpp"
 #include "memory/space.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "utilities/bitMap.inline.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/growableArray.hpp"
 class PerRegionTable: public CHeapObj<mtGC> {
   friend class OtherRegionsTable;
   friend class HeapRegionRemSetIterator;
   HeapRegion*     _hr;
   BitMap          _bm;
   jint            _occupied;
   // next pointer for free/allocated 'all' list
   PerRegionTable* _next;
   // prev pointer for the allocated 'all' list
   PerRegionTable* _prev;
   // next pointer in collision list
   PerRegionTable * _collision_list_next;
   // Global free list of PRTs
   static PerRegionTable* _free_list;
 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),
     _occupied(0),
     _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
     _collision_list_next(NULL), _next(NULL), _prev(NULL)
   {}
   void add_card_work(CardIdx_t from_card, bool par) {
     if (!_bm.at(from_card)) {
       if (par) {
         if (_bm.par_at_put(from_card, 1)) {
           Atomic::inc(&_occupied);
         }
       } else {
         _bm.at_put(from_card, 1);
         _occupied++;
       }
     }
   }
   void add_reference_work(OopOrNarrowOopStar from, bool par) {
     // Must make this robust in case "from" is not in "_hr", because of
     // concurrency.
     if (G1TraceHeapRegionRememberedSet) {
       gclog_or_tty->print_cr("    PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
                              from,
                              UseCompressedOops
                              ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
                              : (void *)oopDesc::load_decode_heap_oop((oop*)from));
     }
     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 the table used to belong to a continues humongous region and is
     // now reused for the corresponding start humongous region, we need to
     // make sure that we detect this. Thus, we call is_in_reserved_raw()
     // instead of just is_in_reserved() here.
     if (loc_hr->is_in_reserved_raw(from)) {
       size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
       CardIdx_t from_card = (CardIdx_t)
           hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
       assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
              "Must be in range.");
       add_card_work(from_card, par);
     }
   }
 public:
   HeapRegion* hr() const { return _hr; }
   jint occupied() const {
     // Overkill, but if we ever need it...
     // guarantee(_occupied == _bm.count_one_bits(), "Check");
     return _occupied;
   }
   void init(HeapRegion* hr, bool clear_links_to_all_list) {
     if (clear_links_to_all_list) {
       set_next(NULL);
       set_prev(NULL);
     }
     _hr = hr;
     _collision_list_next = NULL;
     _occupied = 0;
     _bm.clear();
   }
   void add_reference(OopOrNarrowOopStar from) {
     add_reference_work(from, /*parallel*/ true);
   }
   void seq_add_reference(OopOrNarrowOopStar from) {
     add_reference_work(from, /*parallel*/ false);
   }
   void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
     HeapWord* hr_bot = hr()->bottom();
     size_t hr_first_card_index = ctbs->index_for(hr_bot);
     bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
     recount_occupied();
   }
   void add_card(CardIdx_t from_card_index) {
     add_card_work(from_card_index, /*parallel*/ true);
   }
   void seq_add_card(CardIdx_t 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;
   }
   // Requires "from" to be in "hr()".
   bool contains_reference(OopOrNarrowOopStar 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);
   }
   // Bulk-free the PRTs from prt to last, assumes that they are
   // linked together using their _next field.
   static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
     while (true) {
       PerRegionTable* fl = _free_list;
       last->set_next(fl);
       PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
       if (res == fl) {
         return;
       }
     }
     ShouldNotReachHere();
   }
   static void free(PerRegionTable* prt) {
     bulk_free(prt, prt);
   }
   // Returns an initialized PerRegionTable instance.
   static PerRegionTable* alloc(HeapRegion* hr) {
     PerRegionTable* fl = _free_list;
     while (fl != NULL) {
       PerRegionTable* nxt = fl->next();
       PerRegionTable* res =
         (PerRegionTable*)
         Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
       if (res == fl) {
         fl->init(hr, true);
         return fl;
       } else {
         fl = _free_list;
       }
     }
     assert(fl == NULL, "Loop condition.");
     return new PerRegionTable(hr);
   }
   PerRegionTable* next() const { return _next; }
   void set_next(PerRegionTable* next) { _next = next; }
   PerRegionTable* prev() const { return _prev; }
   void set_prev(PerRegionTable* prev) { _prev = prev; }
   // Accessor and Modification routines for the pointer for the
   // singly linked collision list that links the PRTs within the
   // OtherRegionsTable::_fine_grain_regions hash table.
   //
   // It might be useful to also make the collision list doubly linked
   // to avoid iteration over the collisions list during scrubbing/deletion.
   // OTOH there might not be many collisions.
   PerRegionTable* collision_list_next() const {
     return _collision_list_next;
   }
   void set_collision_list_next(PerRegionTable* next) {
     _collision_list_next = next;
   }
   PerRegionTable** collision_list_next_addr() {
     return &_collision_list_next;
   }
   static size_t fl_mem_size() {
     PerRegionTable* cur = _free_list;
     size_t res = 0;
     while (cur != NULL) {
       res += cur->mem_size();
       cur = cur->next();
     }
     return res;
   }
   static void test_fl_mem_size();
 };
 PerRegionTable* PerRegionTable::_free_list = NULL;
 size_t OtherRegionsTable::_max_fine_entries = 0;
 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
 size_t OtherRegionsTable::_fine_eviction_stride = 0;
 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
   _g1h(G1CollectedHeap::heap()),
   _hr(hr), _m(m),
   _coarse_map(G1CollectedHeap::heap()->max_regions(),
               false /* in-resource-area */),
   _fine_grain_regions(NULL),
   _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
   _n_fine_entries(0), _n_coarse_entries(0),
   _fine_eviction_start(0),
   _sparse_table(hr)
 {
   typedef PerRegionTable* PerRegionTablePtr;
   if (_max_fine_entries == 0) {
     assert(_mod_max_fine_entries_mask == 0, "Both or none.");
     size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
     _max_fine_entries = (size_t)1 << max_entries_log;
     _mod_max_fine_entries_mask = _max_fine_entries - 1;
     assert(_fine_eviction_sample_size == 0
            && _fine_eviction_stride == 0, "All init at same time.");
     _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
     _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
   }
   _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
                         mtGC, 0, AllocFailStrategy::RETURN_NULL);
   if (_fine_grain_regions == NULL) {
     vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
                           "Failed to allocate _fine_grain_entries.");
   }
   for (size_t i = 0; i < _max_fine_entries; i++) {
     _fine_grain_regions[i] = NULL;
   }
 }
 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
   // We always append to the beginning of the list for convenience;
   // the order of entries in this list does not matter.
   if (_first_all_fine_prts != NULL) {
     assert(_first_all_fine_prts->prev() == NULL, "invariant");
     _first_all_fine_prts->set_prev(prt);
     prt->set_next(_first_all_fine_prts);
   } else {
     // this is the first element we insert. Adjust the "last" pointer
     _last_all_fine_prts = prt;
     assert(prt->next() == NULL, "just checking");
   }
   // the new element is always the first element without a predecessor
   prt->set_prev(NULL);
   _first_all_fine_prts = prt;
   assert(prt->prev() == NULL, "just checking");
   assert(_first_all_fine_prts == prt, "just checking");
   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
          "just checking");
   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
          "just checking");
   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
          "just checking");
 }
 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
   if (prt->prev() != NULL) {
     assert(_first_all_fine_prts != prt, "just checking");
     prt->prev()->set_next(prt->next());
     // removing the last element in the list?
     if (_last_all_fine_prts == prt) {
       _last_all_fine_prts = prt->prev();
     }
   } else {
     assert(_first_all_fine_prts == prt, "just checking");
     _first_all_fine_prts = prt->next();
     // list is empty now?
     if (_first_all_fine_prts == NULL) {
       _last_all_fine_prts = NULL;
     }
   }
   if (prt->next() != NULL) {
     prt->next()->set_prev(prt->prev());
   }
   prt->set_next(NULL);
   prt->set_prev(NULL);
   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
          "just checking");
   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
          "just checking");
   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
          "just checking");
 }
 int**  OtherRegionsTable::_from_card_cache = NULL;
 uint   OtherRegionsTable::_from_card_cache_max_regions = 0;
 size_t OtherRegionsTable::_from_card_cache_mem_size = 0;
 void OtherRegionsTable::init_from_card_cache(uint max_regions) {
   guarantee(_from_card_cache == NULL, "Should not call this multiple times");
   uint n_par_rs = HeapRegionRemSet::num_par_rem_sets();
   _from_card_cache_max_regions = max_regions;
   _from_card_cache = Padded2DArray<int, mtGC>::create_unfreeable(n_par_rs,
                                                                  _from_card_cache_max_regions,
                                                                  &_from_card_cache_mem_size);
   for (uint i = 0; i < n_par_rs; i++) {
     for (uint j = 0; j < _from_card_cache_max_regions; j++) {
       _from_card_cache[i][j] = -1;  // An invalid value.
     }
   }
 }
 void OtherRegionsTable::shrink_from_card_cache(uint new_n_regs) {
   for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
     assert(new_n_regs <= _from_card_cache_max_regions, "Must be within max.");
     for (uint 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 (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
     for (uint 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(OopOrNarrowOopStar from, int tid) {
   size_t cur_hrs_ind = (size_t) hr()->hrs_index();
   if (G1TraceHeapRegionRememberedSet) {
     gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
                                                     from,
                                                     UseCompressedOops
                                                     ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
                                                     : (void *)oopDesc::load_decode_heap_oop((oop*)from));
   }
   int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
   if (G1TraceHeapRegionRememberedSet) {
     gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
                   hr()->bottom(), from_card,
                   _from_card_cache[tid][cur_hrs_ind]);
   }
   if (from_card == _from_card_cache[tid][cur_hrs_ind]) {
     if (G1TraceHeapRegionRememberedSet) {
       gclog_or_tty->print_cr("  from-card cache hit.");
     }
     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);
   RegionIdx_t from_hrs_ind = (RegionIdx_t) from_hr->hrs_index();
   // If the region is already coarsened, return.
   if (_coarse_map.at(from_hrs_ind)) {
     if (G1TraceHeapRegionRememberedSet) {
       gclog_or_tty->print_cr("  coarse map hit.");
     }
     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;
   PerRegionTable* 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;
       CardIdx_t card_index = from_card - from_hr_bot_card_index;
       assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
              "Must be in range.");
       if (G1HRRSUseSparseTable &&
           _sparse_table.add_card(from_hrs_ind, card_index)) {
         if (G1RecordHRRSOops) {
           HeapRegionRemSet::record(hr(), from);
           if (G1TraceHeapRegionRememberedSet) {
             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);
           }
         }
         if (G1TraceHeapRegionRememberedSet) {
           gclog_or_tty->print_cr("   added card to sparse table.");
         }
         assert(contains_reference_locked(from), "We just added it!");
         return;
       } else {
         if (G1TraceHeapRegionRememberedSet) {
           gclog_or_tty->print_cr("   [tid %d] sparse table entry "
                         "overflow(f: %d, t: %d)",
                         tid, from_hrs_ind, cur_hrs_ind);
         }
       }
       if (_n_fine_entries == _max_fine_entries) {
         prt = delete_region_table();
         // There is no need to clear the links to the 'all' list here:
         // prt will be reused immediately, i.e. remain in the 'all' list.
         prt->init(from_hr, false /* clear_links_to_all_list */);
       } else {
         prt = PerRegionTable::alloc(from_hr);
         link_to_all(prt);
       }
       PerRegionTable* first_prt = _fine_grain_regions[ind];
       prt->set_collision_list_next(first_prt);
       _fine_grain_regions[ind] = prt;
       _n_fine_entries++;
       if (G1HRRSUseSparseTable) {
         // Transfer from sparse to fine-grain.
         SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrs_ind);
         assert(sprt_entry != NULL, "There should have been an entry");
         for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
           CardIdx_t c = sprt_entry->card(i);
           if (c != SparsePRTEntry::NullEntry) {
             prt->add_card(c);
           }
         }
         // Now we can delete the sparse entry.
         bool res = _sparse_table.delete_entry(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);
   if (G1RecordHRRSOops) {
     HeapRegionRemSet::record(hr(), from);
     if (G1TraceHeapRegionRememberedSet) {
       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);
     }
   }
   assert(contains_reference(from), "We just added it!");
 }
 PerRegionTable*
 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
   PerRegionTable* prt = _fine_grain_regions[ind];
   while (prt != NULL && prt->hr() != hr) {
     prt = prt->collision_list_next();
   }
   // Loop postcondition is the method postcondition.
   return prt;
 }
 jint OtherRegionsTable::_n_coarsenings = 0;
 PerRegionTable* OtherRegionsTable::delete_region_table() {
   assert(_m->owned_by_self(), "Precondition");
   assert(_n_fine_entries == _max_fine_entries, "Precondition");
   PerRegionTable* max = NULL;
   jint max_occ = 0;
   PerRegionTable** max_prev;
   size_t max_ind;
   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.");
     }
     PerRegionTable** prev = &_fine_grain_regions[ii];
     PerRegionTable* 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->collision_list_next_addr();
       cur = cur->collision_list_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;
   }
   guarantee(max != NULL, "Since _n_fine_entries > 0");
   // Set the corresponding coarse bit.
   size_t max_hrs_index = (size_t) max->hr()->hrs_index();
   if (!_coarse_map.at(max_hrs_index)) {
     _coarse_map.at_put(max_hrs_index, true);
     _n_coarse_entries++;
     if (G1TraceHeapRegionRememberedSet) {
       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);
     }
   }
   // Unsplice.
   *max_prev = max->collision_list_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 %u:", hr()->hrs_index());
   }
   assert(_coarse_map.size() == region_bm->size(), "Precondition");
   if (G1RSScrubVerbose) {
     gclog_or_tty->print("   Coarse map: before = "SIZE_FORMAT"...",
                         _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 = "SIZE_FORMAT".", _n_coarse_entries);
   }
   // Now do the fine-grained maps.
   for (size_t i = 0; i < _max_fine_entries; i++) {
     PerRegionTable* cur = _fine_grain_regions[i];
     PerRegionTable** prev = &_fine_grain_regions[i];
     while (cur != NULL) {
       PerRegionTable* nxt = cur->collision_list_next();
       // If the entire region is dead, eliminate.
       if (G1RSScrubVerbose) {
         gclog_or_tty->print_cr("     For other region %u:",
                                cur->hr()->hrs_index());
       }
       if (!region_bm->at((size_t) cur->hr()->hrs_index())) {
         *prev = nxt;
         cur->set_collision_list_next(NULL);
         _n_fine_entries--;
         if (G1RSScrubVerbose) {
           gclog_or_tty->print_cr("          deleted via region map.");
         }
         unlink_from_all(cur);
         PerRegionTable::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_collision_list_next(NULL);
           _n_fine_entries--;
           unlink_from_all(cur);
           PerRegionTable::free(cur);
         } else {
           prev = cur->collision_list_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 {
   size_t sum = occ_fine();
   sum += occ_sparse();
   sum += occ_coarse();
   return sum;
 }
 size_t OtherRegionsTable::occ_fine() const {
   size_t sum = 0;
   size_t num = 0;
   PerRegionTable * cur = _first_all_fine_prts;
   while (cur != NULL) {
     sum += cur->occupied();
     cur = cur->next();
     num++;
   }
   guarantee(num == _n_fine_entries, "just checking");
   return sum;
 }
 size_t OtherRegionsTable::occ_coarse() const {
   return (_n_coarse_entries * HeapRegion::CardsPerRegion);
 }
 size_t OtherRegionsTable::occ_sparse() const {
   return _sparse_table.occupied();
 }
 size_t OtherRegionsTable::mem_size() const {
   size_t sum = 0;
   // all PRTs are of the same size so it is sufficient to query only one of them.
   if (_first_all_fine_prts != NULL) {
     assert(_last_all_fine_prts != NULL &&
       _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
     sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
   }
   sum += (sizeof(PerRegionTable*) * _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();
 }
 void OtherRegionsTable::clear_fcc() {
   uint hrs_idx = hr()->hrs_index();
   uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
   for (uint i = 0; i < num_par_remsets; i++) {
     _from_card_cache[i][hrs_idx] = -1;
   }
 }
 void OtherRegionsTable::clear() {
   // if there are no entries, skip this step
   if (_first_all_fine_prts != NULL) {
     guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
     PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
     memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
   } else {
     guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
   }
   _first_all_fine_prts = _last_all_fine_prts = 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.
   uint hr_ind = hr()->hrs_index();
   for (uint 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.");
   PerRegionTable** prev_addr = &_fine_grain_regions[ind];
   PerRegionTable* prt = *prev_addr;
   while (prt != NULL && prt->hr() != hr) {
     prev_addr = prt->collision_list_next_addr();
     prt = prt->collision_list_next();
   }
   if (prt != NULL) {
     assert(prt->hr() == hr, "Loop postcondition.");
     *prev_addr = prt->collision_list_next();
     unlink_from_all(prt);
     PerRegionTable::free(prt);
     _n_fine_entries--;
     return true;
   } else {
     return false;
   }
 }
 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar 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(OopOrNarrowOopStar from) const {
   HeapRegion* hr = _g1h->heap_region_containing_raw(from);
   if (hr == NULL) return false;
   RegionIdx_t hr_ind = (RegionIdx_t) hr->hrs_index();
   // Is this region in the coarse map?
   if (_coarse_map.at(hr_ind)) return true;
   PerRegionTable* 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");
     CardIdx_t card_index = from_card - hr_bot_card_index;
     assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
            "Must be in range.");
     return _sparse_table.contains_card(hr_ind, card_index);
   }
 }
 void
 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
   _sparse_table.do_cleanup_work(hrrs_cleanup_task);
 }
 // Determines how many threads can add records to an rset in parallel.
 // This can be done by either mutator threads together with the
 // concurrent refinement threads or GC threads.
 uint HeapRegionRemSet::num_par_rem_sets() {
   return (uint)MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), ParallelGCThreads);
 }
 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
                                    HeapRegion* hr)
   : _bosa(bosa),
     _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #"UINT32_FORMAT, hr->hrs_index()), true),
     _code_roots(), _other_regions(hr, &_m) {
   reset_for_par_iteration();
 }
 void HeapRegionRemSet::setup_remset_size() {
   // Setup sparse and fine-grain tables sizes.
   // table_size = base * (log(region_size / 1M) + 1)
   const int LOG_M = 20;
   int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
   if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
     G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
   }
   if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
     G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
   }
   guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
 }
 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;
 }
 #ifndef PRODUCT
 void HeapRegionRemSet::print() {
   HeapRegionRemSetIterator iter(this);
   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);
   }
   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::clear() {
   MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
   clear_locked();
 }
 void HeapRegionRemSet::clear_locked() {
   _code_roots.clear();
   _other_regions.clear();
   assert(occupied_locked() == 0, "Should be clear.");
   reset_for_par_iteration();
 }
 void HeapRegionRemSet::reset_for_par_iteration() {
   _iter_state = Unclaimed;
   _iter_claimed = 0;
   // It's good to check this to make sure that the two methods are in sync.
   assert(verify_ready_for_par_iteration(), "post-condition");
 }
 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
                              BitMap* region_bm, BitMap* card_bm) {
   _other_regions.scrub(ctbs, region_bm, card_bm);
 }
 // Code roots support
 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
   assert(nm != NULL, "sanity");
   _code_roots.add(nm);
 }
 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
   assert(nm != NULL, "sanity");
   _code_roots.remove(nm);
   // Check that there were no duplicates
   guarantee(!_code_roots.contains(nm), "duplicate entry found");
 }
 class NMethodMigrationOopClosure : public OopClosure {
   G1CollectedHeap* _g1h;
   HeapRegion* _from;
   nmethod* _nm;
   uint _num_self_forwarded;
   template <class T> void do_oop_work(T* p) {
     T heap_oop = oopDesc::load_heap_oop(p);
     if (!oopDesc::is_null(heap_oop)) {
       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
       if (_from->is_in(obj)) {
         // Reference still points into the source region.
         // Since roots are immediately evacuated this means that
         // we must have self forwarded the object
         assert(obj->is_forwarded(),
                err_msg("code roots should be immediately evacuated. "
                        "Ref: "PTR_FORMAT", "
                        "Obj: "PTR_FORMAT", "
                        "Region: "HR_FORMAT,
                        p, (void*) obj, HR_FORMAT_PARAMS(_from)));
         assert(obj->forwardee() == obj,
                err_msg("not self forwarded? obj = "PTR_FORMAT, (void*)obj));
         // The object has been self forwarded.
         // Note, if we're during an initial mark pause, there is
         // no need to explicitly mark object. It will be marked
         // during the regular evacuation failure handling code.
         _num_self_forwarded++;
       } else {
         // The reference points into a promotion or to-space region
         HeapRegion* to = _g1h->heap_region_containing(obj);
         to->rem_set()->add_strong_code_root(_nm);
       }
     }
   }
 public:
   NMethodMigrationOopClosure(G1CollectedHeap* g1h, HeapRegion* from, nmethod* nm):
     _g1h(g1h), _from(from), _nm(nm), _num_self_forwarded(0) {}
   void do_oop(narrowOop* p) { do_oop_work(p); }
   void do_oop(oop* p)       { do_oop_work(p); }
   uint retain() { return _num_self_forwarded > 0; }
 };
 void HeapRegionRemSet::migrate_strong_code_roots() {
   assert(hr()->in_collection_set(), "only collection set regions");
   assert(!hr()->isHumongous(),
          err_msg("humongous region "HR_FORMAT" should not have been added to the collection set",
                  HR_FORMAT_PARAMS(hr())));
   ResourceMark rm;
   // List of code blobs to retain for this region
   GrowableArray<nmethod*> to_be_retained(10);
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   while (!_code_roots.is_empty()) {
     nmethod *nm = _code_roots.pop();
     if (nm != NULL) {
       NMethodMigrationOopClosure oop_cl(g1h, hr(), nm);
       nm->oops_do(&oop_cl);
       if (oop_cl.retain()) {
         to_be_retained.push(nm);
       }
     }
   }
   // Now push any code roots we need to retain
   assert(to_be_retained.is_empty() || hr()->evacuation_failed(),
          "Retained nmethod list must be empty or "
          "evacuation of this region failed");
   while (to_be_retained.is_nonempty()) {
     nmethod* nm = to_be_retained.pop();
     assert(nm != NULL, "sanity");
     add_strong_code_root(nm);
   }
 }
 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
   _code_roots.nmethods_do(blk);
 }
 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
   return _code_roots.mem_size();
 }
 //-------------------- Iteration --------------------
 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
   _hrrs(hrrs),
   _g1h(G1CollectedHeap::heap()),
   _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(HeapRegion::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(&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 == HeapRegion::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((uint) _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 == (size_t) HeapRegion::CardsPerRegion) {
       _cur_region_cur_card = 0;
       _fine_cur_prt = _fine_cur_prt->collision_list_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 < HeapRegion::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;
 }
 OopOrNarrowOopStar* 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, OopOrNarrowOopStar f) {
   if (_recorded_oops == NULL) {
     assert(_n_recorded == 0
            && _recorded_cards == NULL
            && _recorded_regions == NULL,
            "Inv");
     _recorded_oops    = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
     _recorded_cards   = NEW_C_HEAP_ARRAY(HeapWord*,          MaxRecorded, mtGC);
     _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*,        MaxRecorded, mtGC);
   }
   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, mtGC);
     _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
   }
   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]);
   }
 }
 void HeapRegionRemSet::reset_for_cleanup_tasks() {
   SparsePRT::reset_for_cleanup_tasks();
 }
 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
   _other_regions.do_cleanup_work(hrrs_cleanup_task);
 }
 void
 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
   SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
 }
 #ifndef PRODUCT
 void PerRegionTable::test_fl_mem_size() {
   PerRegionTable* dummy = alloc(NULL);
   free(dummy);
   guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
   // try to reset the state
   _free_list = NULL;
   delete dummy;
 }
 void HeapRegionRemSet::test_prt() {
   PerRegionTable::test_fl_mem_size();
 }
 void HeapRegionRemSet::test() {
   os::sleep(Thread::current(), (jlong)5000, false);
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   // Run with "-XX:G1LogRSetRegionEntries=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((OopOrNarrowOopStar)hr1_start);
   hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
   hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
   hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
   hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
   hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
   hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
   hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
   hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
   // Now cause a coarsening.
   hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
   hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
   // Now, does iteration yield these three?
   HeapRegionRemSetIterator iter(hrrs);
   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@96b1c2e06e25 (annotated)

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