Mercurial > hg > graal-jvmci-8

comparison src/share/vm/memory/metachunk.cpp @ 7208:eade6b2e4782

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
8003554: NPG: move Metablock and Metachunk code out of metaspace.cpp Reviewed-by: coleenp
author jmasa
date Thu, 29 Nov 2012 10:09:04 -0800
parents
children e51c9860cf66
comparison
equal deleted inserted replaced
7207:0f80645e9c26 7208:eade6b2e4782
1 /*
2 * Copyright (c) 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 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/metachunk.hpp"
28 #include "utilities/copy.hpp"
29 #include "utilities/debug.hpp"
30
31 //
32 // Future modification
33 //
34 // The Metachunk can conceivable be replaced by the Chunk in
35 // allocation.hpp. Note that the latter Chunk is the space for
36 // allocation (allocations from the chunk are out of the space in
37 // the Chunk after the header for the Chunk) where as Metachunks
38 // point to space in a VirtualSpace. To replace Metachunks with
39 // Chunks, change Chunks so that they can be allocated out of a VirtualSpace.
40
41 const size_t metadata_chunk_initialize = 0xf7f7f7f7;
42
43 size_t Metachunk::_overhead =
44 Chunk::aligned_overhead_size(sizeof(Metachunk)) / BytesPerWord;
45
46 // Metachunk methods
47
48 Metachunk* Metachunk::initialize(MetaWord* ptr, size_t word_size) {
49 // Set bottom, top, and end. Allow space for the Metachunk itself
50 Metachunk* chunk = (Metachunk*) ptr;
51
52 MetaWord* chunk_bottom = ptr + _overhead;
53 chunk->set_bottom(ptr);
54 chunk->set_top(chunk_bottom);
55 MetaWord* chunk_end = ptr + word_size;
56 assert(chunk_end > chunk_bottom, "Chunk must be too small");
57 chunk->set_end(chunk_end);
58 chunk->set_next(NULL);
59 chunk->set_word_size(word_size);
60 #ifdef ASSERT
61 size_t data_word_size = pointer_delta(chunk_end, chunk_bottom, sizeof(MetaWord));
62 Copy::fill_to_words((HeapWord*) chunk_bottom, data_word_size, metadata_chunk_initialize);
63 #endif
64 return chunk;
65 }
66
67
68 MetaWord* Metachunk::allocate(size_t word_size) {
69 MetaWord* result = NULL;
70 // If available, bump the pointer to allocate.
71 if (free_word_size() >= word_size) {
72 result = _top;
73 _top = _top + word_size;
74 }
75 return result;
76 }
77
78 // _bottom points to the start of the chunk including the overhead.
79 size_t Metachunk::used_word_size() {
80 return pointer_delta(_top, _bottom, sizeof(MetaWord));
81 }
82
83 size_t Metachunk::free_word_size() {
84 return pointer_delta(_end, _top, sizeof(MetaWord));
85 }
86
87 size_t Metachunk::capacity_word_size() {
88 return pointer_delta(_end, _bottom, sizeof(MetaWord));
89 }
90
91 void Metachunk::print_on(outputStream* st) const {
92 st->print_cr("Metachunk:"
93 " bottom " PTR_FORMAT " top " PTR_FORMAT
94 " end " PTR_FORMAT " size " SIZE_FORMAT,
95 bottom(), top(), end(), word_size());
96 }
97
98 #ifndef PRODUCT
99 void Metachunk::mangle() {
100 // Mangle the payload of the chunk and not the links that
101 // maintain list of chunks.
102 HeapWord* start = (HeapWord*)(bottom() + overhead());
103 size_t word_size = capacity_word_size() - overhead();
104 Copy::fill_to_words(start, word_size, metadata_chunk_initialize);
105 }
106 #endif // PRODUCT
107
108 void Metachunk::verify() {
109 #ifdef ASSERT
110 // Cannot walk through the blocks unless the blocks have
111 // headers with sizes.
112 assert(_bottom <= _top &&
113 _top <= _end,
114 "Chunk has been smashed");
115 #endif
116 return;
117 }