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 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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 * 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_SHARED_CARDTABLEMODREFBSFORCTRS_HPP

#define SHARE_VM_GC_SHARED_CARDTABLEMODREFBSFORCTRS_HPP

#include "gc/shared/cardTableModRefBS.hpp"

class CardTableRS;

class DirtyCardToOopClosure;

class OopsInGenClosure;

// A specialization for the CardTableRS gen rem set.

class CardTableModRefBSForCTRS: public CardTableModRefBS {

  friend class CardTableRS;

public:

  CardTableModRefBSForCTRS(MemRegion whole_heap);

  ~CardTableModRefBSForCTRS();

  virtual void initialize();

  void set_CTRS(CardTableRS* rs) { _rs = rs; }

private:

  CardTableRS* _rs;

  // *** Support for parallel card scanning.

  // dirty and precleaned are equivalent wrt younger_refs_iter.

  static bool card_is_dirty_wrt_gen_iter(jbyte cv) {

    return cv == dirty_card || cv == precleaned_card;

  }

  // Returns "true" iff the value "cv" will cause the card containing it

  // to be scanned in the current traversal.  May be overridden by

  // subtypes.

  bool card_will_be_scanned(jbyte cv);

  // Returns "true" iff the value "cv" may have represented a dirty card at

  // some point.

  bool card_may_have_been_dirty(jbyte cv);

  // Iterate over the portion of the card-table which covers the given

  // region mr in the given space and apply cl to any dirty sub-regions

  // of mr. Clears the dirty cards as they are processed.

  void non_clean_card_iterate_possibly_parallel(Space* sp, MemRegion mr,

                                                OopsInGenClosure* cl, CardTableRS* ct,

                                                uint n_threads);

  // Work method used to implement non_clean_card_iterate_possibly_parallel()

  // above in the parallel case.

  void non_clean_card_iterate_parallel_work(Space* sp, MemRegion mr,

                                            OopsInGenClosure* cl, CardTableRS* ct,

                                            uint n_threads);

  // This is an array, one element per covered region of the card table.

  // Each entry is itself an array, with one element per chunk in the

  // covered region.  Each entry of these arrays is the lowest non-clean

  // card of the corresponding chunk containing part of an object from the

  // previous chunk, or else NULL.

  typedef jbyte*  CardPtr;

  typedef CardPtr* CardArr;

  CardArr* _lowest_non_clean;

  size_t*  _lowest_non_clean_chunk_size;

  uintptr_t* _lowest_non_clean_base_chunk_index;

  volatile int* _last_LNC_resizing_collection;

  // Initializes "lowest_non_clean" to point to the array for the region

  // covering "sp", and "lowest_non_clean_base_chunk_index" to the chunk

  // index of the corresponding to the first element of that array.

  // Ensures that these arrays are of sufficient size, allocating if necessary.

  // May be called by several threads concurrently.

  void get_LNC_array_for_space(Space* sp,

                               jbyte**& lowest_non_clean,

                               uintptr_t& lowest_non_clean_base_chunk_index,

                               size_t& lowest_non_clean_chunk_size);

  // Returns the number of chunks necessary to cover "mr".

  size_t chunks_to_cover(MemRegion mr) {

    return (size_t)(addr_to_chunk_index(mr.last()) -

                    addr_to_chunk_index(mr.start()) + 1);

  }

  // Returns the index of the chunk in a stride which

  // covers the given address.

  uintptr_t addr_to_chunk_index(const void* addr) {

    uintptr_t card = (uintptr_t) byte_for(addr);

    return card / ParGCCardsPerStrideChunk;

  }

  // Apply cl, which must either itself apply dcto_cl or be dcto_cl,

  // to the cards in the stride (of n_strides) within the given space.

  void process_stride(Space* sp,

                      MemRegion used,

                      jint stride, int n_strides,

                      OopsInGenClosure* cl,

                      CardTableRS* ct,

                      jbyte** lowest_non_clean,

                      uintptr_t lowest_non_clean_base_chunk_index,

                      size_t lowest_non_clean_chunk_size);

  // Makes sure that chunk boundaries are handled appropriately, by

  // adjusting the min_done of dcto_cl, and by using a special card-table

  // value to indicate how min_done should be set.

  void process_chunk_boundaries(Space* sp,

                                DirtyCardToOopClosure* dcto_cl,

                                MemRegion chunk_mr,

                                MemRegion used,

                                jbyte** lowest_non_clean,

                                uintptr_t lowest_non_clean_base_chunk_index,

                                size_t    lowest_non_clean_chunk_size);

};

template<>

struct BarrierSet::GetName<CardTableModRefBSForCTRS> {

  static const BarrierSet::Name value = BarrierSet::CardTableForRS;

};

#endif // include guard