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 * Copyright (c) 2013, 2015, 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.

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#ifndef SHARE_VM_GC_G1_G1CARDCOUNTS_HPP

#define SHARE_VM_GC_G1_G1CARDCOUNTS_HPP

#include "gc/g1/g1RegionToSpaceMapper.hpp"

#include "memory/allocation.hpp"

#include "memory/virtualspace.hpp"

#include "utilities/globalDefinitions.hpp"

class CardTableModRefBS;

class G1CardCounts;

class G1CollectedHeap;

class G1RegionToSpaceMapper;

class HeapRegion;

class G1CardCountsMappingChangedListener : public G1MappingChangedListener {

 private:

  G1CardCounts* _counts;

 public:

  void set_cardcounts(G1CardCounts* counts) { _counts = counts; }

  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);

};

// Table to track the number of times a card has been refined. Once

// a card has been refined a certain number of times, it is

// considered 'hot' and its refinement is delayed by inserting the

// card into the hot card cache. The card will then be refined when

// it is evicted from the hot card cache, or when the hot card cache

// is 'drained' during the next evacuation pause.

class G1CardCounts: public CHeapObj<mtGC> {

  G1CardCountsMappingChangedListener _listener;

  G1CollectedHeap* _g1h;

  // The table of counts

  jubyte* _card_counts;

  // Max capacity of the reserved space for the counts table

  size_t _reserved_max_card_num;

  // CardTable bottom.

  const jbyte* _ct_bot;

  // Barrier set

  CardTableModRefBS* _ct_bs;

  // Returns true if the card counts table has been reserved.

  bool has_reserved_count_table() { return _card_counts != NULL; }

  // Returns true if the card counts table has been reserved and committed.

  bool has_count_table() {

    return has_reserved_count_table();

  }

  size_t ptr_2_card_num(const jbyte* card_ptr) {

    assert(card_ptr >= _ct_bot,

           "Invalid card pointer: "

           "card_ptr: " PTR_FORMAT ", "

           "_ct_bot: " PTR_FORMAT,

           p2i(card_ptr), p2i(_ct_bot));

    size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte));

    assert(card_num < _reserved_max_card_num,

           "card pointer out of range: " PTR_FORMAT, p2i(card_ptr));

    return card_num;

  }

  jbyte* card_num_2_ptr(size_t card_num) {

    assert(card_num < _reserved_max_card_num,

           "card num out of range: " SIZE_FORMAT, card_num);

    return (jbyte*) (_ct_bot + card_num);

  }

  // Clear the counts table for the given (exclusive) index range.

  void clear_range(size_t from_card_num, size_t to_card_num);

 public:

  G1CardCounts(G1CollectedHeap* g1h);

  // Return the number of slots needed for a card counts table

  // that covers mem_region_words words.

  static size_t compute_size(size_t mem_region_size_in_words);

  // Returns how many bytes of the heap a single byte of the card counts table

  // corresponds to.

  static size_t heap_map_factor();

  void initialize(G1RegionToSpaceMapper* mapper);

  // Increments the refinement count for the given card.

  // Returns the pre-increment count value.

  uint add_card_count(jbyte* card_ptr);

  // Returns true if the given count is high enough to be considered

  // 'hot'; false otherwise.

  bool is_hot(uint count);

  // Clears the card counts for the cards spanned by the region

  void clear_region(HeapRegion* hr);

  // Clears the card counts for the cards spanned by the MemRegion

  void clear_range(MemRegion mr);

  // Clear the entire card counts table during GC.

  void clear_all();

};

#endif // SHARE_VM_GC_G1_G1CARDCOUNTS_HPP