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

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 * 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).

 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

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#ifndef SHARE_GC_PARALLEL_ADJOININGGENERATIONSFORHETEROHEAP_HPP

#define SHARE_GC_PARALLEL_ADJOININGGENERATIONSFORHETEROHEAP_HPP

#include "gc/parallel/adjoiningGenerations.hpp"

class AdjoiningGenerationsForHeteroHeap : public AdjoiningGenerations {

  friend class VMStructs;

private:

  // Maximum total size of the generations. This is equal to the heap size specified by user.

  // When adjusting young and old generation sizes, we need ensure that sum of the generation sizes does not exceed this.

  size_t _total_size_limit;

  size_t total_size_limit() const {

    return _total_size_limit;

  }

  // HeteroVirtualSpaces creates non-overlapping virtual spaces. Here _low and _high do not share a reserved space, i.e. there is no boundary

  // separating the two virtual spaces.

  class HeteroVirtualSpaces : public AdjoiningVirtualSpaces {

    size_t _max_total_size;

    size_t _min_old_byte_size;

    size_t _min_young_byte_size;

    size_t _max_old_byte_size;

    size_t _max_young_byte_size;

    // Internally we access the virtual spaces using these methods. It increases readability, since we were not really

    // dealing with adjoining virtual spaces separated by a boundary as is the case in base class.

    // Externally they are accessed using low() and high() methods of base class.

    PSVirtualSpace* young_vs() { return high(); }

    PSVirtualSpace* old_vs() { return low(); }

  public:

    HeteroVirtualSpaces(ReservedSpace rs,

                        size_t min_old_byte_size,

    // Increase old generation size and decrease young generation size by same amount

    bool adjust_boundary_up(size_t size_in_bytes);

    // Increase young generation size and decrease old generation size by same amount

    bool adjust_boundary_down(size_t size_in_bytes);

    size_t max_young_size() const { return _max_young_byte_size; }

    size_t max_old_size() const { return _max_old_byte_size; }

    void initialize(size_t initial_old_reserved_size, size_t init_low_byte_size,

                    size_t init_high_byte_size);

  };

public:

  // Given the size policy, calculate the total amount of memory that needs to be reserved.

  // We need to reserve more memory than Xmx, since we use non-overlapping virtual spaces for the young and old generations.

  // Return the total byte size of the reserved space

  size_t reserved_byte_size();

};

#endif // SHARE_GC_PARALLEL_ADJOININGGENERATIONSFORHETEROHEAP_HPP