1 /* 2 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP 27 28 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp" 29 #include "gc_implementation/parallelScavenge/asPSOldGen.hpp" 30 #include "gc_implementation/parallelScavenge/asPSYoungGen.hpp" 31 32 33 // Contains two generations that both use an AdjoiningVirtualSpaces. 34 // The two generations are adjacent in the reserved space for the 35 // heap. Each generation has a virtual space and shrinking and 36 // expanding of the generations can still be down with that 37 // virtual space as was previously done. If expanding of reserved 38 // size of a generation is required, the adjacent generation 39 // must be shrunk. Adjusting the boundary between the generations 40 // is called for in this class. 41 42 class AdjoiningGenerations : public CHeapObj<mtGC> { 43 friend class VMStructs; 44 private: 45 // The young generation and old generation, respectively 46 PSYoungGen* _young_gen; 47 PSOldGen* _old_gen; 48 49 // The spaces used by the two generations. 50 AdjoiningVirtualSpaces _virtual_spaces; 51 52 // Move boundary up to expand old gen. Checks are made to 53 // determine if the move can be done with specified limits. 54 void request_old_gen_expansion(size_t desired_change_in_bytes); 55 // Move boundary down to expand young gen. 56 bool request_young_gen_expansion(size_t desired_change_in_bytes); 57 58 public: 59 AdjoiningGenerations(ReservedSpace rs, 60 size_t init_low_byte_size, 61 size_t min_low_byte_size, 62 size_t max_low_byte_size, 63 size_t init_high_byte_size, 64 size_t min_high_byte_size, 65 size_t max_high_bytes_size, 66 size_t alignment); 67 68 // Accessors 69 PSYoungGen* young_gen() { return _young_gen; } 70 PSOldGen* old_gen() { return _old_gen; } 71 72 AdjoiningVirtualSpaces* virtual_spaces() { return &_virtual_spaces; } 73 74 // Additional space is needed in the old generation. Check 75 // the available space and attempt to move the boundary if more space 76 // is needed. The growth is not guaranteed to occur. 77 void adjust_boundary_for_old_gen_needs(size_t desired_change_in_bytes); 78 // Similary for a growth of the young generation. 79 void adjust_boundary_for_young_gen_needs(size_t eden_size, size_t survivor_size); 80 81 // Return the total byte size of the reserved space 82 // for the adjoining generations. 83 size_t reserved_byte_size(); 84 }; 85 86 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGGENERATIONS_HPP