src/hotspot/share/gc/g1/g1ConcurrentMarkBitMap.cpp

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * 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
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#include "precompiled.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
#include "gc/g1/heapRegion.hpp"
#include "memory/virtualspace.hpp"

void G1CMBitMap::print_on_error(outputStream* st, const char* prefix) const {
  _bm.print_on_error(st, prefix);
}

size_t G1CMBitMap::compute_size(size_t heap_size) {
  return ReservedSpace::allocation_align_size_up(heap_size / mark_distance());
}

size_t G1CMBitMap::mark_distance() {
  return MinObjAlignmentInBytes * BitsPerByte;
}

void G1CMBitMap::initialize(MemRegion heap, G1RegionToSpaceMapper* storage) {
  _covered = heap;

  _bm = BitMapView((BitMap::bm_word_t*) storage->reserved().start(), _covered.word_size() >> _shifter);

  storage->set_mapping_changed_listener(&_listener);
}

void G1CMBitMapMappingChangedListener::on_commit(uint start_region, size_t num_regions, bool zero_filled) {
  if (zero_filled) {
    return;
  }
  // We need to clear the bitmap on commit, removing any existing information.
  MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_region), num_regions * HeapRegion::GrainWords);
  _bm->clear_range(mr);
}

void G1CMBitMap::clear_range(MemRegion mr) {
  MemRegion intersection = mr.intersection(_covered);
  assert(!intersection.is_empty(),
         "Given range from " PTR_FORMAT " to " PTR_FORMAT " is completely outside the heap",
         p2i(mr.start()), p2i(mr.end()));
  // convert address range into offset range
  _bm.at_put_range(addr_to_offset(intersection.start()),
                   addr_to_offset(intersection.end()), false);
}

void G1CMBitMap::clear_region(HeapRegion* region) {
 if (!region->is_empty()) {
   MemRegion mr(region->bottom(), region->top());
   clear_range(mr);
 }
}