/*

 * Copyright (c) 2014, 2018, 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_G1REGIONTOSPACEMAPPER_HPP

#define SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP

#include "gc/g1/g1PageBasedVirtualSpace.hpp"

#include "memory/allocation.hpp"

#include "utilities/debug.hpp"

class WorkGang;

class G1MappingChangedListener {

 public:

  // Fired after commit of the memory, i.e. the memory this listener is registered

  // for can be accessed.

  // Zero_filled indicates that the memory can be considered as filled with zero bytes

  // when called.

  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled) = 0;

};

// Maps region based commit/uncommit requests to the underlying page sized virtual

// space.

class G1RegionToSpaceMapper : public CHeapObj<mtGC> {

 private:

  G1MappingChangedListener* _listener;

 protected:

  // Backing storage.

  G1PageBasedVirtualSpace _storage;

  size_t _region_granularity;

  // Mapping management

  CHeapBitMap _commit_map;

  G1RegionToSpaceMapper(ReservedSpace rs, size_t used_size, size_t page_size, size_t region_granularity, size_t commit_factor, MemoryType type);

  void fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled);

 public:

  MemRegion reserved() { return _storage.reserved(); }

  size_t reserved_size() { return _storage.reserved_size(); }

  size_t committed_size() { return _storage.committed_size(); }

  void set_mapping_changed_listener(G1MappingChangedListener* listener) { _listener = listener; }

  virtual ~G1RegionToSpaceMapper() {}

  bool is_committed(uintptr_t idx) const {

    return _commit_map.at(idx);

  }

  virtual void commit_regions(uint start_idx, size_t num_regions = 1, WorkGang* pretouch_workers = NULL) = 0;

  virtual void uncommit_regions(uint start_idx, size_t num_regions = 1) = 0;

  // Creates an appropriate G1RegionToSpaceMapper for the given parameters.

  // The actual space to be used within the given reservation is given by actual_size.

  // This is because some OSes need to round up the reservation size to guarantee

  // alignment of page_size.

  // The byte_translation_factor defines how many bytes in a region correspond to

  // a single byte in the data structure this mapper is for.

  // Eg. in the card table, this value corresponds to the size a single card

  // table entry corresponds to in the heap.

  static G1RegionToSpaceMapper* create_mapper(ReservedSpace rs,

                                              size_t actual_size,

                                              size_t page_size,

                                              size_t region_granularity,

                                              size_t byte_translation_factor,

                                              MemoryType type);

};

#endif // SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP