duke@435: /*
trims@1907:  * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: 
duke@435: // Contains two generations that both use an AdjoiningVirtualSpaces.
duke@435: // The two generations are adjacent in the reserved space for the
duke@435: // heap.  Each generation has a virtual space and shrinking and
duke@435: // expanding of the generations can still be down with that
duke@435: // virtual space as was previously done.  If expanding of reserved
duke@435: // size of a generation is required, the adjacent generation
duke@435: // must be shrunk.  Adjusting the boundary between the generations
duke@435: // is called for in this class.
duke@435: 
duke@435: class AdjoiningGenerations : public CHeapObj {
duke@435:   friend class VMStructs;
duke@435:  private:
duke@435:   // The young generation and old generation, respectively
duke@435:   PSYoungGen* _young_gen;
duke@435:   PSOldGen* _old_gen;
duke@435: 
duke@435:   // The spaces used by the two generations.
duke@435:   AdjoiningVirtualSpaces _virtual_spaces;
duke@435: 
duke@435:   // Move boundary up to expand old gen.  Checks are made to
duke@435:   // determine if the move can be done with specified limits.
duke@435:   void request_old_gen_expansion(size_t desired_change_in_bytes);
duke@435:   // Move boundary down to expand young gen.
duke@435:   bool request_young_gen_expansion(size_t desired_change_in_bytes);
duke@435: 
duke@435:  public:
duke@435:   AdjoiningGenerations(ReservedSpace rs,
duke@435:                        size_t init_low_byte_size,
duke@435:                        size_t min_low_byte_size,
duke@435:                        size_t max_low_byte_size,
duke@435:                        size_t init_high_byte_size,
duke@435:                        size_t min_high_byte_size,
duke@435:                        size_t max_high_bytes_size,
duke@435:                        size_t alignment);
duke@435: 
duke@435:   // Accessors
duke@435:   PSYoungGen* young_gen() { return _young_gen; }
duke@435:   PSOldGen* old_gen() { return _old_gen; }
duke@435: 
duke@435:   AdjoiningVirtualSpaces* virtual_spaces() { return &_virtual_spaces; }
duke@435: 
duke@435:   // Additional space is needed in the old generation.  Check
duke@435:   // the available space and attempt to move the boundary if more space
duke@435:   // is needed.  The growth is not guaranteed to occur.
duke@435:   void adjust_boundary_for_old_gen_needs(size_t desired_change_in_bytes);
duke@435:   // Similary for a growth of the young generation.
duke@435:   void adjust_boundary_for_young_gen_needs(size_t eden_size, size_t survivor_size);
duke@435: 
duke@435:   // Return the total byte size of the reserved space
duke@435:   // for the adjoining generations.
duke@435:   size_t reserved_byte_size();
duke@435: };