jdk8-mips64-public/hotspot: src/share/vm/memory/cardTableModRefBS.cpp@0fbdb4381b99 (annotated)

src/share/vm/memory/cardTableModRefBS.cpp@0fbdb4381b99 (annotated)

src/share/vm/memory/cardTableModRefBS.cpp

Mon, 09 Mar 2009 13:28:46 -0700

author: xdono
date: Mon, 09 Mar 2009 13:28:46 -0700
changeset 1014: 0fbdb4381b99
parent 924: 2494ab195856
child 1063: 7bb995fbd3c0
permissions: -rw-r--r--

6814575: Update copyright year
Summary: Update copyright for files that have been modified in 2009, up to 03/09
Reviewed-by: katleman, tbell, ohair

 /*
  * Copyright 2000-2009 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.
  *
  */
 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
 // enumerate ref fields that have been modified (since the last
 // enumeration.)
 # include "incls/_precompiled.incl"
 # include "incls/_cardTableModRefBS.cpp.incl"
 size_t CardTableModRefBS::cards_required(size_t covered_words)
 {
   // Add one for a guard card, used to detect errors.
   const size_t words = align_size_up(covered_words, card_size_in_words);
   return words / card_size_in_words + 1;
 }
 size_t CardTableModRefBS::compute_byte_map_size()
 {
   assert(_guard_index == cards_required(_whole_heap.word_size()) - 1,
                                         "unitialized, check declaration order");
   assert(_page_size != 0, "unitialized, check declaration order");
   const size_t granularity = os::vm_allocation_granularity();
   return align_size_up(_guard_index + 1, MAX2(_page_size, granularity));
 }
 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap,
                                      int max_covered_regions):
   ModRefBarrierSet(max_covered_regions),
   _whole_heap(whole_heap),
   _guard_index(cards_required(whole_heap.word_size()) - 1),
   _last_valid_index(_guard_index - 1),
   _page_size(os::vm_page_size()),
   _byte_map_size(compute_byte_map_size())
 {
   _kind = BarrierSet::CardTableModRef;
   HeapWord* low_bound  = _whole_heap.start();
   HeapWord* high_bound = _whole_heap.end();
   assert((uintptr_t(low_bound)  & (card_size - 1))  == 0, "heap must start at card boundary");
   assert((uintptr_t(high_bound) & (card_size - 1))  == 0, "heap must end at card boundary");
   assert(card_size <= 512, "card_size must be less than 512"); // why?
   _covered   = new MemRegion[max_covered_regions];
   _committed = new MemRegion[max_covered_regions];
   if (_covered == NULL || _committed == NULL)
     vm_exit_during_initialization("couldn't alloc card table covered region set.");
   int i;
   for (i = 0; i < max_covered_regions; i++) {
     _covered[i].set_word_size(0);
     _committed[i].set_word_size(0);
   }
   _cur_covered_regions = 0;
   const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 :
     MAX2(_page_size, (size_t) os::vm_allocation_granularity());
   ReservedSpace heap_rs(_byte_map_size, rs_align, false);
   os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1,
                        _page_size, heap_rs.base(), heap_rs.size());
   if (!heap_rs.is_reserved()) {
     vm_exit_during_initialization("Could not reserve enough space for the "
                                   "card marking array");
   }
   // The assember store_check code will do an unsigned shift of the oop,
   // then add it to byte_map_base, i.e.
   //
   //   _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift)
   _byte_map = (jbyte*) heap_rs.base();
   byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);
   assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");
   assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");
   jbyte* guard_card = &_byte_map[_guard_index];
   uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size);
   _guard_region = MemRegion((HeapWord*)guard_page, _page_size);
   if (!os::commit_memory((char*)guard_page, _page_size, _page_size)) {
     // Do better than this for Merlin
     vm_exit_out_of_memory(_page_size, "card table last card");
   }
   *guard_card = last_card;
    _lowest_non_clean =
     NEW_C_HEAP_ARRAY(CardArr, max_covered_regions);
   _lowest_non_clean_chunk_size =
     NEW_C_HEAP_ARRAY(size_t, max_covered_regions);
   _lowest_non_clean_base_chunk_index =
     NEW_C_HEAP_ARRAY(uintptr_t, max_covered_regions);
   _last_LNC_resizing_collection =
     NEW_C_HEAP_ARRAY(int, max_covered_regions);
   if (_lowest_non_clean == NULL
       || _lowest_non_clean_chunk_size == NULL
       || _lowest_non_clean_base_chunk_index == NULL
       || _last_LNC_resizing_collection == NULL)
     vm_exit_during_initialization("couldn't allocate an LNC array.");
   for (i = 0; i < max_covered_regions; i++) {
     _lowest_non_clean[i] = NULL;
     _lowest_non_clean_chunk_size[i] = 0;
     _last_LNC_resizing_collection[i] = -1;
   }
   if (TraceCardTableModRefBS) {
     gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: ");
     gclog_or_tty->print_cr("  "
                   "  &_byte_map[0]: " INTPTR_FORMAT
                   "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,
                   &_byte_map[0],
                   &_byte_map[_last_valid_index]);
     gclog_or_tty->print_cr("  "
                   "  byte_map_base: " INTPTR_FORMAT,
                   byte_map_base);
   }
 }
 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) {
   int i;
   for (i = 0; i < _cur_covered_regions; i++) {
     if (_covered[i].start() == base) return i;
     if (_covered[i].start() > base) break;
   }
   // If we didn't find it, create a new one.
   assert(_cur_covered_regions < _max_covered_regions,
          "too many covered regions");
   // Move the ones above up, to maintain sorted order.
   for (int j = _cur_covered_regions; j > i; j--) {
     _covered[j] = _covered[j-1];
     _committed[j] = _committed[j-1];
   }
   int res = i;
   _cur_covered_regions++;
   _covered[res].set_start(base);
   _covered[res].set_word_size(0);
   jbyte* ct_start = byte_for(base);
   uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size);
   _committed[res].set_start((HeapWord*)ct_start_aligned);
   _committed[res].set_word_size(0);
   return res;
 }
 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     if (_covered[i].contains(addr)) {
       return i;
     }
   }
   assert(0, "address outside of heap?");
   return -1;
 }
 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const {
   HeapWord* max_end = NULL;
   for (int j = 0; j < ind; j++) {
     HeapWord* this_end = _committed[j].end();
     if (this_end > max_end) max_end = this_end;
   }
   return max_end;
 }
 MemRegion CardTableModRefBS::committed_unique_to_self(int self,
                                                       MemRegion mr) const {
   MemRegion result = mr;
   for (int r = 0; r < _cur_covered_regions; r += 1) {
     if (r != self) {
       result = result.minus(_committed[r]);
     }
   }
   // Never include the guard page.
   result = result.minus(_guard_region);
   return result;
 }
 void CardTableModRefBS::resize_covered_region(MemRegion new_region) {
   // We don't change the start of a region, only the end.
   assert(_whole_heap.contains(new_region),
            "attempt to cover area not in reserved area");
   debug_only(verify_guard();)
   // collided is true if the expansion would push into another committed region
   debug_only(bool collided = false;)
   int const ind = find_covering_region_by_base(new_region.start());
   MemRegion const old_region = _covered[ind];
   assert(old_region.start() == new_region.start(), "just checking");
   if (new_region.word_size() != old_region.word_size()) {
     // Commit new or uncommit old pages, if necessary.
     MemRegion cur_committed = _committed[ind];
     // Extend the end of this _commited region
     // to cover the end of any lower _committed regions.
     // This forms overlapping regions, but never interior regions.
     HeapWord* const max_prev_end = largest_prev_committed_end(ind);
     if (max_prev_end > cur_committed.end()) {
       cur_committed.set_end(max_prev_end);
     }
     // Align the end up to a page size (starts are already aligned).
     jbyte* const new_end = byte_after(new_region.last());
     HeapWord* new_end_aligned =
       (HeapWord*) align_size_up((uintptr_t)new_end, _page_size);
     assert(new_end_aligned >= (HeapWord*) new_end,
            "align up, but less");
     int ri = 0;
     for (ri = 0; ri < _cur_covered_regions; ri++) {
       if (ri != ind) {
         if (_committed[ri].contains(new_end_aligned)) {
           assert((new_end_aligned >= _committed[ri].start()) &&
                  (_committed[ri].start() > _committed[ind].start()),
                  "New end of committed region is inconsistent");
           new_end_aligned = _committed[ri].start();
           assert(new_end_aligned > _committed[ind].start(),
             "New end of committed region is before start");
           debug_only(collided = true;)
           // Should only collide with 1 region
           break;
         }
       }
     }
 #ifdef ASSERT
     for (++ri; ri < _cur_covered_regions; ri++) {
       assert(!_committed[ri].contains(new_end_aligned),
         "New end of committed region is in a second committed region");
     }
 #endif
     // The guard page is always committed and should not be committed over.
     HeapWord* const new_end_for_commit = MIN2(new_end_aligned,
                                               _guard_region.start());
     if (new_end_for_commit > cur_committed.end()) {
       // Must commit new pages.
       MemRegion const new_committed =
         MemRegion(cur_committed.end(), new_end_for_commit);
       assert(!new_committed.is_empty(), "Region should not be empty here");
       if (!os::commit_memory((char*)new_committed.start(),
                              new_committed.byte_size(), _page_size)) {
         // Do better than this for Merlin
         vm_exit_out_of_memory(new_committed.byte_size(),
                 "card table expansion");
       }
     // Use new_end_aligned (as opposed to new_end_for_commit) because
     // the cur_committed region may include the guard region.
     } else if (new_end_aligned < cur_committed.end()) {
       // Must uncommit pages.
       MemRegion const uncommit_region =
         committed_unique_to_self(ind, MemRegion(new_end_aligned,
                                                 cur_committed.end()));
       if (!uncommit_region.is_empty()) {
         if (!os::uncommit_memory((char*)uncommit_region.start(),
                                  uncommit_region.byte_size())) {
           assert(false, "Card table contraction failed");
           // The call failed so don't change the end of the
           // committed region.  This is better than taking the
           // VM down.
           new_end_aligned = _committed[ind].end();
         }
       }
     }
     // In any case, we can reset the end of the current committed entry.
     _committed[ind].set_end(new_end_aligned);
     // The default of 0 is not necessarily clean cards.
     jbyte* entry;
     if (old_region.last() < _whole_heap.start()) {
       entry = byte_for(_whole_heap.start());
     } else {
       entry = byte_after(old_region.last());
     }
     assert(index_for(new_region.last()) <  _guard_index,
       "The guard card will be overwritten");
     // This line commented out cleans the newly expanded region and
     // not the aligned up expanded region.
     // jbyte* const end = byte_after(new_region.last());
     jbyte* const end = (jbyte*) new_end_for_commit;
     assert((end >= byte_after(new_region.last())) || collided,
       "Expect to be beyond new region unless impacting another region");
     // do nothing if we resized downward.
 #ifdef ASSERT
     for (int ri = 0; ri < _cur_covered_regions; ri++) {
       if (ri != ind) {
         // The end of the new committed region should not
         // be in any existing region unless it matches
         // the start of the next region.
         assert(!_committed[ri].contains(end) ||
                (_committed[ri].start() == (HeapWord*) end),
                "Overlapping committed regions");
       }
     }
 #endif
     if (entry < end) {
       memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte)));
     }
   }
   // In any case, the covered size changes.
   _covered[ind].set_word_size(new_region.word_size());
   if (TraceCardTableModRefBS) {
     gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: ");
     gclog_or_tty->print_cr("  "
                   "  _covered[%d].start(): " INTPTR_FORMAT
                   "  _covered[%d].last(): " INTPTR_FORMAT,
                   ind, _covered[ind].start(),
                   ind, _covered[ind].last());
     gclog_or_tty->print_cr("  "
                   "  _committed[%d].start(): " INTPTR_FORMAT
                   "  _committed[%d].last(): " INTPTR_FORMAT,
                   ind, _committed[ind].start(),
                   ind, _committed[ind].last());
     gclog_or_tty->print_cr("  "
                   "  byte_for(start): " INTPTR_FORMAT
                   "  byte_for(last): " INTPTR_FORMAT,
                   byte_for(_covered[ind].start()),
                   byte_for(_covered[ind].last()));
     gclog_or_tty->print_cr("  "
                   "  addr_for(start): " INTPTR_FORMAT
                   "  addr_for(last): " INTPTR_FORMAT,
                   addr_for((jbyte*) _committed[ind].start()),
                   addr_for((jbyte*) _committed[ind].last()));
   }
   debug_only(verify_guard();)
 }
 // Note that these versions are precise!  The scanning code has to handle the
 // fact that the write barrier may be either precise or imprecise.
 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal) {
   inline_write_ref_field(field, newVal);
 }
 bool CardTableModRefBS::claim_card(size_t card_index) {
   jbyte val = _byte_map[card_index];
   if (val != claimed_card_val()) {
     jbyte res = Atomic::cmpxchg((jbyte) claimed_card_val(), &_byte_map[card_index], val);
     if (res == val)
       return true;
     else return false;
   }
   return false;
 }
 void CardTableModRefBS::non_clean_card_iterate(Space* sp,
                                                MemRegion mr,
                                                DirtyCardToOopClosure* dcto_cl,
                                                MemRegionClosure* cl,
                                                bool clear) {
   if (!mr.is_empty()) {
     int n_threads = SharedHeap::heap()->n_par_threads();
     if (n_threads > 0) {
 #ifndef SERIALGC
       par_non_clean_card_iterate_work(sp, mr, dcto_cl, cl, clear, n_threads);
 #else  // SERIALGC
       fatal("Parallel gc not supported here.");
 #endif // SERIALGC
     } else {
       non_clean_card_iterate_work(mr, cl, clear);
     }
   }
 }
 // NOTE: For this to work correctly, it is important that
 // we look for non-clean cards below (so as to catch those
 // marked precleaned), rather than look explicitly for dirty
 // cards (and miss those marked precleaned). In that sense,
 // the name precleaned is currently somewhat of a misnomer.
 void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr,
                                                     MemRegionClosure* cl,
                                                     bool clear) {
   // Figure out whether we have to worry about parallelism.
   bool is_par = (SharedHeap::heap()->n_par_threads() > 1);
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (mri.word_size() > 0) {
       jbyte* cur_entry = byte_for(mri.last());
       jbyte* limit = byte_for(mri.start());
       while (cur_entry >= limit) {
         jbyte* next_entry = cur_entry - 1;
         if (*cur_entry != clean_card) {
           size_t non_clean_cards = 1;
           // Should the next card be included in this range of dirty cards.
           while (next_entry >= limit && *next_entry != clean_card) {
             non_clean_cards++;
             cur_entry = next_entry;
             next_entry--;
           }
           // The memory region may not be on a card boundary.  So that
           // objects beyond the end of the region are not processed, make
           // cur_cards precise with regard to the end of the memory region.
           MemRegion cur_cards(addr_for(cur_entry),
                               non_clean_cards * card_size_in_words);
           MemRegion dirty_region = cur_cards.intersection(mri);
           if (clear) {
             for (size_t i = 0; i < non_clean_cards; i++) {
               // Clean the dirty cards (but leave the other non-clean
               // alone.)  If parallel, do the cleaning atomically.
               jbyte cur_entry_val = cur_entry[i];
               if (card_is_dirty_wrt_gen_iter(cur_entry_val)) {
                 if (is_par) {
                   jbyte res = Atomic::cmpxchg(clean_card, &cur_entry[i], cur_entry_val);
                   assert(res != clean_card,
                          "Dirty card mysteriously cleaned");
                 } else {
                   cur_entry[i] = clean_card;
                 }
               }
             }
           }
           cl->do_MemRegion(dirty_region);
         }
         cur_entry = next_entry;
       }
     }
   }
 }
 void CardTableModRefBS::mod_oop_in_space_iterate(Space* sp,
                                                  OopClosure* cl,
                                                  bool clear,
                                                  bool before_save_marks) {
   // Note that dcto_cl is resource-allocated, so there is no
   // corresponding "delete".
   DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision());
   MemRegion used_mr;
   if (before_save_marks) {
     used_mr = sp->used_region_at_save_marks();
   } else {
     used_mr = sp->used_region();
   }
   non_clean_card_iterate(sp, used_mr, dcto_cl, dcto_cl, clear);
 }
 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
   jbyte* cur  = byte_for(mr.start());
   jbyte* last = byte_after(mr.last());
   while (cur < last) {
     *cur = dirty_card;
     cur++;
   }
 }
 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) dirty_MemRegion(mri);
   }
 }
 void CardTableModRefBS::clear_MemRegion(MemRegion mr) {
   // Be conservative: only clean cards entirely contained within the
   // region.
   jbyte* cur;
   if (mr.start() == _whole_heap.start()) {
     cur = byte_for(mr.start());
   } else {
     assert(mr.start() > _whole_heap.start(), "mr is not covered.");
     cur = byte_after(mr.start() - 1);
   }
   jbyte* last = byte_after(mr.last());
   memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte)));
 }
 void CardTableModRefBS::clear(MemRegion mr) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) clear_MemRegion(mri);
   }
 }
 void CardTableModRefBS::dirty(MemRegion mr) {
   jbyte* first = byte_for(mr.start());
   jbyte* last  = byte_after(mr.last());
   memset(first, dirty_card, last-first);
 }
 // NOTES:
 // (1) Unlike mod_oop_in_space_iterate() above, dirty_card_iterate()
 //     iterates over dirty cards ranges in increasing address order.
 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
                                            MemRegionClosure* cl) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) {
       jbyte *cur_entry, *next_entry, *limit;
       for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
            cur_entry <= limit;
            cur_entry  = next_entry) {
         next_entry = cur_entry + 1;
         if (*cur_entry == dirty_card) {
           size_t dirty_cards;
           // Accumulate maximal dirty card range, starting at cur_entry
           for (dirty_cards = 1;
                next_entry <= limit && *next_entry == dirty_card;
                dirty_cards++, next_entry++);
           MemRegion cur_cards(addr_for(cur_entry),
                               dirty_cards*card_size_in_words);
           cl->do_MemRegion(cur_cards);
         }
       }
     }
   }
 }
 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr,
                                                           bool reset,
                                                           int reset_val) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) {
       jbyte* cur_entry, *next_entry, *limit;
       for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
            cur_entry <= limit;
            cur_entry  = next_entry) {
         next_entry = cur_entry + 1;
         if (*cur_entry == dirty_card) {
           size_t dirty_cards;
           // Accumulate maximal dirty card range, starting at cur_entry
           for (dirty_cards = 1;
                next_entry <= limit && *next_entry == dirty_card;
                dirty_cards++, next_entry++);
           MemRegion cur_cards(addr_for(cur_entry),
                               dirty_cards*card_size_in_words);
           if (reset) {
             for (size_t i = 0; i < dirty_cards; i++) {
               cur_entry[i] = reset_val;
             }
           }
           return cur_cards;
         }
       }
     }
   }
   return MemRegion(mr.end(), mr.end());
 }
 // Set all the dirty cards in the given region to "precleaned" state.
 void CardTableModRefBS::preclean_dirty_cards(MemRegion mr) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (!mri.is_empty()) {
       jbyte *cur_entry, *limit;
       for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last());
            cur_entry <= limit;
            cur_entry++) {
         if (*cur_entry == dirty_card) {
           *cur_entry = precleaned_card;
         }
       }
     }
   }
 }
 uintx CardTableModRefBS::ct_max_alignment_constraint() {
   return card_size * os::vm_page_size();
 }
 void CardTableModRefBS::verify_guard() {
   // For product build verification
   guarantee(_byte_map[_guard_index] == last_card,
             "card table guard has been modified");
 }
 void CardTableModRefBS::verify() {
   verify_guard();
 }
 #ifndef PRODUCT
 class GuaranteeNotModClosure: public MemRegionClosure {
   CardTableModRefBS* _ct;
 public:
   GuaranteeNotModClosure(CardTableModRefBS* ct) : _ct(ct) {}
   void do_MemRegion(MemRegion mr) {
     jbyte* entry = _ct->byte_for(mr.start());
     guarantee(*entry != CardTableModRefBS::clean_card,
               "Dirty card in region that should be clean");
   }
 };
 void CardTableModRefBS::verify_clean_region(MemRegion mr) {
   GuaranteeNotModClosure blk(this);
   non_clean_card_iterate_work(mr, &blk, false);
 }
 #endif
 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) {
   return
     CardTableModRefBS::card_will_be_scanned(cv) ||
     _rs->is_prev_nonclean_card_val(cv);
 };
 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) {
   return
     cv != clean_card &&
     (CardTableModRefBS::card_may_have_been_dirty(cv) ||
      CardTableRS::youngergen_may_have_been_dirty(cv));
 };

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/cardTableModRefBS.cpp@0fbdb4381b99 (annotated)

src/share/vm/memory/cardTableModRefBS.cpp