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 /*

  * Copyright (c) 2013, 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

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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP

 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"

 #include "memory/allocation.hpp"

 #include "runtime/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,

            err_msg("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 >= 0 && card_num < _reserved_max_card_num,

            err_msg("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 >= 0 && card_num < _reserved_max_card_num,

            err_msg("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);

   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_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP