1 /* 2 * Copyright (c) 2003, 2015, 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_PARALLEL_ADJOININGGENERATIONS_HPP 26 #define SHARE_VM_GC_PARALLEL_ADJOININGGENERATIONS_HPP 27 28 #include "gc/parallel/adjoiningVirtualSpaces.hpp" 29 #include "gc/parallel/asPSOldGen.hpp" 30 #include "gc/parallel/asPSYoungGen.hpp" 31 #include "gc/parallel/generationSizer.hpp" 32 33 34 // Contains two generations that both use an AdjoiningVirtualSpaces. 35 // The two generations are adjacent in the reserved space for the 36 // heap. Each generation has a virtual space and shrinking and 37 // expanding of the generations can still be down with that 38 // virtual space as was previously done. If expanding of reserved 39 // size of a generation is required, the adjacent generation 40 // must be shrunk. Adjusting the boundary between the generations 41 // is called for in this class. 42 43 class AdjoiningGenerations : public CHeapObj<mtGC> { 44 friend class VMStructs; 45 private: 46 // The young generation and old generation, respectively 47 PSYoungGen* _young_gen; 48 PSOldGen* _old_gen; 49 50 // The spaces used by the two generations. 51 AdjoiningVirtualSpaces _virtual_spaces; 52 53 // Move boundary up to expand old gen. Checks are made to 54 // determine if the move can be done with specified limits. 55 void request_old_gen_expansion(size_t desired_change_in_bytes); 56 // Move boundary down to expand young gen. 57 bool request_young_gen_expansion(size_t desired_change_in_bytes); 58 59 public: 60 AdjoiningGenerations(ReservedSpace rs, GenerationSizer* policy, size_t alignment); 61 62 // Accessors young_gen()63 PSYoungGen* young_gen() { return _young_gen; } old_gen()64 PSOldGen* old_gen() { return _old_gen; } 65 virtual_spaces()66 AdjoiningVirtualSpaces* virtual_spaces() { return &_virtual_spaces; } 67 68 // Additional space is needed in the old generation. Check 69 // the available space and attempt to move the boundary if more space 70 // is needed. The growth is not guaranteed to occur. 71 void adjust_boundary_for_old_gen_needs(size_t desired_change_in_bytes); 72 // Similarly for a growth of the young generation. 73 void adjust_boundary_for_young_gen_needs(size_t eden_size, size_t survivor_size); 74 75 // Return the total byte size of the reserved space 76 // for the adjoining generations. 77 size_t reserved_byte_size(); 78 }; 79 80 #endif // SHARE_VM_GC_PARALLEL_ADJOININGGENERATIONS_HPP 81