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 /*

  * Copyright (c) 2003, 2010, 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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  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP

 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp"

 #include "gc_implementation/parallelScavenge/asPSOldGen.hpp"

 #include "gc_implementation/parallelScavenge/asPSYoungGen.hpp"

 #include "gc_implementation/parallelScavenge/psPermGen.hpp"

 // Contains two generations that both use an AdjoiningVirtualSpaces.

 // The two generations are adjacent in the reserved space for the

 // heap.  Each generation has a virtual space and shrinking and

 // expanding of the generations can still be down with that

 // virtual space as was previously done.  If expanding of reserved

 // size of a generation is required, the adjacent generation

 // must be shrunk.  Adjusting the boundary between the generations

 // is called for in this class.

 class AdjoiningGenerations : public CHeapObj {

   friend class VMStructs;

  private:

   // The young generation and old generation, respectively

   PSYoungGen* _young_gen;

   PSOldGen* _old_gen;

   // The spaces used by the two generations.

   AdjoiningVirtualSpaces _virtual_spaces;

   // Move boundary up to expand old gen.  Checks are made to

   // determine if the move can be done with specified limits.

   void request_old_gen_expansion(size_t desired_change_in_bytes);

   // Move boundary down to expand young gen.

   bool request_young_gen_expansion(size_t desired_change_in_bytes);

  public:

   AdjoiningGenerations(ReservedSpace rs,

                        size_t init_low_byte_size,

                        size_t min_low_byte_size,

                        size_t max_low_byte_size,

                        size_t init_high_byte_size,

                        size_t min_high_byte_size,

                        size_t max_high_bytes_size,

                        size_t alignment);

   // Accessors

   PSYoungGen* young_gen() { return _young_gen; }

   PSOldGen* old_gen() { return _old_gen; }

   AdjoiningVirtualSpaces* virtual_spaces() { return &_virtual_spaces; }

   // Additional space is needed in the old generation.  Check

   // the available space and attempt to move the boundary if more space

   // is needed.  The growth is not guaranteed to occur.

   void adjust_boundary_for_old_gen_needs(size_t desired_change_in_bytes);

   // Similary for a growth of the young generation.

   void adjust_boundary_for_young_gen_needs(size_t eden_size, size_t survivor_size);

   // Return the total byte size of the reserved space

   // for the adjoining generations.

   size_t reserved_byte_size();

 };

 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP