| /* |
| * 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. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP |
| #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP |
| |
| #include "gc_implementation/parallelScavenge/psVirtualspace.hpp" |
| |
| |
| // Contains two virtual spaces that each can individually span |
| // most of the reserved region but committed parts of which |
| // cannot overlap. |
| // |
| // +-------+ <--- high_boundary for H |
| // | | |
| // | H | |
| // | | |
| // | | |
| // | | |
| // --------- <--- low for H |
| // | | |
| // ========= <--- low_boundary for H, high_boundary for L |
| // | | |
| // | | |
| // | | |
| // --------- <--- high for L |
| // | | |
| // | L | |
| // | | |
| // | | |
| // | | |
| // +-------+ <--- low_boundary for L |
| // |
| // Each virtual space in the AdjoiningVirtualSpaces grows and shrink |
| // within its reserved region (between the low_boundary and the |
| // boundary) independently. If L want to grow above its high_boundary, |
| // then the high_boundary of L and the low_boundary of H must be |
| // moved up consistently. AdjoiningVirtualSpaces provide the |
| // interfaces for moving the this boundary. |
| |
| class AdjoiningVirtualSpaces { |
| // space at the high end and the low end, respectively |
| PSVirtualSpace* _high; |
| PSVirtualSpace* _low; |
| |
| // The reserved space spanned by the two spaces. |
| ReservedSpace _reserved_space; |
| |
| // The minimum byte size for the low space. It will not |
| // be shrunk below this value. |
| size_t _min_low_byte_size; |
| // Same for the high space |
| size_t _min_high_byte_size; |
| |
| const size_t _alignment; |
| |
| public: |
| // Allocates two virtual spaces that will be located at the |
| // high and low ends. Does no initialization. |
| AdjoiningVirtualSpaces(ReservedSpace rs, |
| size_t min_low_byte_size, |
| size_t min_high_byte_size, |
| size_t alignment); |
| |
| // accessors |
| PSVirtualSpace* high() { return _high; } |
| PSVirtualSpace* low() { return _low; } |
| ReservedSpace reserved_space() { return _reserved_space; } |
| size_t min_low_byte_size() { return _min_low_byte_size; } |
| size_t min_high_byte_size() { return _min_high_byte_size; } |
| size_t alignment() const { return _alignment; } |
| |
| // move boundary between the two spaces up |
| bool adjust_boundary_up(size_t size_in_bytes); |
| // and down |
| bool adjust_boundary_down(size_t size_in_bytes); |
| |
| // Maximum byte size for the high space. |
| size_t high_byte_size_limit() { |
| return _reserved_space.size() - _min_low_byte_size; |
| } |
| // Maximum byte size for the low space. |
| size_t low_byte_size_limit() { |
| return _reserved_space.size() - _min_high_byte_size; |
| } |
| |
| // Sets the boundaries for the virtual spaces and commits and |
| // initial size; |
| void initialize(size_t max_low_byte_size, |
| size_t init_low_byte_size, |
| size_t init_high_byte_size); |
| }; |
| |
| #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP |