1 /*
2 * Copyright (c) 2012, 2013, 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 *
78 };
79
80 // Metachunk - Quantum of allocation from a Virtualspace
81 // Metachunks are reused (when freed are put on a global freelist) and
82 // have no permanent association to a SpaceManager.
83
84 // +--------------+ <- end --+ --+
85 // | | | |
86 // | | | free |
87 // | | | |
88 // | | | | size | capacity
89 // | | | |
90 // | | <- top -- + |
91 // | | | |
92 // | | | used |
93 // | | | |
94 // | | | |
95 // +--------------+ <- bottom --+ --+
96
97 class Metachunk : public Metabase<Metachunk> {
98 friend class TestMetachunk;
99 // The VirtualSpaceNode containing this chunk.
100 VirtualSpaceNode* _container;
101
102 // Current allocation top.
103 MetaWord* _top;
104
105 DEBUG_ONLY(bool _is_tagged_free;)
106
107 MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
108 MetaWord* top() const { return _top; }
109
110 public:
111 // Metachunks are allocated out of a MetadataVirtualSpace and
112 // and use some of its space to describe itself (plus alignment
113 // considerations). Metadata is allocated in the rest of the chunk.
114 // This size is the overhead of maintaining the Metachunk within
115 // the space.
116
117 // Alignment of each allocation in the chunks.
118 static size_t object_alignment();
|
1 /*
2 * Copyright (c) 2012, 2016, 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 *
78 };
79
80 // Metachunk - Quantum of allocation from a Virtualspace
81 // Metachunks are reused (when freed are put on a global freelist) and
82 // have no permanent association to a SpaceManager.
83
84 // +--------------+ <- end --+ --+
85 // | | | |
86 // | | | free |
87 // | | | |
88 // | | | | size | capacity
89 // | | | |
90 // | | <- top -- + |
91 // | | | |
92 // | | | used |
93 // | | | |
94 // | | | |
95 // +--------------+ <- bottom --+ --+
96
97 class Metachunk : public Metabase<Metachunk> {
98 friend class MetachunkTest;
99 // The VirtualSpaceNode containing this chunk.
100 VirtualSpaceNode* _container;
101
102 // Current allocation top.
103 MetaWord* _top;
104
105 DEBUG_ONLY(bool _is_tagged_free;)
106
107 MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
108 MetaWord* top() const { return _top; }
109
110 public:
111 // Metachunks are allocated out of a MetadataVirtualSpace and
112 // and use some of its space to describe itself (plus alignment
113 // considerations). Metadata is allocated in the rest of the chunk.
114 // This size is the overhead of maintaining the Metachunk within
115 // the space.
116
117 // Alignment of each allocation in the chunks.
118 static size_t object_alignment();
|