1 /*
2 * Copyright (c) 2012, 2014, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
32
33 class VirtualSpaceNode;
34
35 const size_t metadata_chunk_initialize = 0xf7f7f7f7;
36
object_alignment()37 size_t Metachunk::object_alignment() {
38 // Must align pointers and sizes to 8,
39 // so that 64 bit types get correctly aligned.
40 const size_t alignment = 8;
41
42 // Make sure that the Klass alignment also agree.
43 STATIC_ASSERT(alignment == (size_t)KlassAlignmentInBytes);
44
45 return alignment;
46 }
47
overhead()48 size_t Metachunk::overhead() {
49 return align_size_up(sizeof(Metachunk), object_alignment()) / BytesPerWord;
50 }
51
52 // Metachunk methods
53
Metachunk(size_t word_size,VirtualSpaceNode * container)54 Metachunk::Metachunk(size_t word_size,
55 VirtualSpaceNode* container)
56 : Metabase<Metachunk>(word_size),
57 _top(NULL),
58 _container(container)
59 {
60 _top = initial_top();
61 #ifdef ASSERT
62 set_is_tagged_free(false);
63 size_t data_word_size = pointer_delta(end(),
64 _top,
65 sizeof(MetaWord));
66 Copy::fill_to_words((HeapWord*)_top,
67 data_word_size,
68 metadata_chunk_initialize);
69 #endif
70 }
71
allocate(size_t word_size)72 MetaWord* Metachunk::allocate(size_t word_size) {
73 MetaWord* result = NULL;
74 // If available, bump the pointer to allocate.
75 if (free_word_size() >= word_size) {
76 result = _top;
77 _top = _top + word_size;
78 }
79 return result;
80 }
81
82 // _bottom points to the start of the chunk including the overhead.
used_word_size() const83 size_t Metachunk::used_word_size() const {
84 return pointer_delta(_top, bottom(), sizeof(MetaWord));
85 }
86
free_word_size() const87 size_t Metachunk::free_word_size() const {
88 return pointer_delta(end(), _top, sizeof(MetaWord));
89 }
90
print_on(outputStream * st) const91 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 if (Verbose) {
97 st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT,
98 used_word_size(), free_word_size());
99 }
100 }
101
102 #ifndef PRODUCT
mangle()103 void Metachunk::mangle() {
104 // Mangle the payload of the chunk and not the links that
105 // maintain list of chunks.
106 HeapWord* start = (HeapWord*)(bottom() + overhead());
107 size_t size = word_size() - overhead();
108 Copy::fill_to_words(start, size, metadata_chunk_initialize);
109 }
110 #endif // PRODUCT
111
verify()112 void Metachunk::verify() {
113 #ifdef ASSERT
114 // Cannot walk through the blocks unless the blocks have
115 // headers with sizes.
116 assert(bottom() <= _top &&
117 _top <= (MetaWord*)end(),
118 "Chunk has been smashed");
119 #endif
120 return;
121 }
122
123 /////////////// Unit tests ///////////////
124
125 #ifndef PRODUCT
126
127 class TestMetachunk {
128 public:
test()129 static void test() {
130 size_t size = 2 * 1024 * 1024;
131 void* memory = malloc(size);
132 assert(memory != NULL, "Failed to malloc 2MB");
133
134 Metachunk* metachunk = ::new (memory) Metachunk(size / BytesPerWord, NULL);
135
136 assert(metachunk->bottom() == (MetaWord*)metachunk, "assert");
137 assert(metachunk->end() == (uintptr_t*)metachunk + metachunk->size(), "assert");
138
139 // Check sizes
140 assert(metachunk->size() == metachunk->word_size(), "assert");
141 assert(metachunk->word_size() == pointer_delta(metachunk->end(), metachunk->bottom(),
142 sizeof(MetaWord*)), "assert");
143
144 // Check usage
145 assert(metachunk->used_word_size() == metachunk->overhead(), "assert");
146 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
147 assert(metachunk->top() == metachunk->initial_top(), "assert");
148 assert(metachunk->is_empty(), "assert");
149
150 // Allocate
151 size_t alloc_size = 64; // Words
152 assert(is_size_aligned(alloc_size, Metachunk::object_alignment()), "assert");
153
154 MetaWord* mem = metachunk->allocate(alloc_size);
155
156 // Check post alloc
157 assert(mem == metachunk->initial_top(), "assert");
158 assert(mem + alloc_size == metachunk->top(), "assert");
159 assert(metachunk->used_word_size() == metachunk->overhead() + alloc_size, "assert");
160 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
161 assert(!metachunk->is_empty(), "assert");
162
163 // Clear chunk
164 metachunk->reset_empty();
165
166 // Check post clear
167 assert(metachunk->used_word_size() == metachunk->overhead(), "assert");
168 assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert");
169 assert(metachunk->top() == metachunk->initial_top(), "assert");
170 assert(metachunk->is_empty(), "assert");
171
172 free(memory);
173 }
174 };
175
TestMetachunk_test()176 void TestMetachunk_test() {
177 TestMetachunk::test();
178 }
179
180 #endif
181