1 /*
2 * Copyright (c) 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 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1PreserveMarkQueue.hpp"
27 #include "memory/allocation.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "oops/oopsHierarchy.hpp"
30
31 class G1PreserveMarkChunk {
32 const size_t _capacity;
33 size_t _write_index;
34 size_t _read_index;
35 G1PreserveMarkQueueEntry* _data;
36
37 public:
38 G1PreserveMarkChunk(size_t capacity) : _capacity(capacity), _write_index(0), _read_index(0), _next(NULL) {
39 _data = NEW_C_HEAP_ARRAY(G1PreserveMarkQueueEntry, _capacity, mtGC);
40 }
41
42 ~G1PreserveMarkChunk() {
43 FREE_C_HEAP_ARRAY(G1PreserveMarkQueueEntry, _data, mtGC);
44 }
45
46 bool has_data() {
47 return _write_index > _read_index;
48 }
49
50 bool is_full() {
51 assert(_write_index <= _capacity, "written too far");
52 return _write_index == _capacity;
53 }
54
55 void append(const G1PreserveMarkQueueEntry& entry) {
56 assert(!is_full(), "overflow");
57 _data[_write_index++] = entry;
58 }
59
60 G1PreserveMarkQueueEntry remove_first() {
61 assert(has_data(), "empty");
62 return _data[_read_index++];
63 }
64
65 G1PreserveMarkChunk* _next;
66 };
67
68 bool G1PreserveMarkQueue::has_data() {
69 return _current_read_chunk != NULL && _current_read_chunk->has_data();
70 }
71
72 void G1PreserveMarkQueue::append(const oop& obj, const markOop& mark) {
73 G1PreserveMarkQueueEntry entry = {obj, mark};
74 if (_current_write_chunk == NULL) {
75 assert(_current_read_chunk == NULL, "must be");
76 _current_write_chunk = new G1PreserveMarkChunk(new_chunk_capacity());
77 _current_read_chunk = _current_write_chunk;
78 } else if (_current_write_chunk->is_full()) {
79 G1PreserveMarkChunk* new_chunk = new G1PreserveMarkChunk(new_chunk_capacity());
80 _current_write_chunk->_next = new_chunk;
81 _current_write_chunk = new_chunk;
82 }
83
84 assert(!_current_write_chunk->is_full(), "full");
85
86 _current_write_chunk->append(entry);
87 }
88
89 G1PreserveMarkQueueEntry G1PreserveMarkQueue::remove_first() {
90 assert(has_data(), "empty");
91 G1PreserveMarkQueueEntry entry = _current_read_chunk->remove_first();
92
93 if (!_current_read_chunk->has_data()) {
94 G1PreserveMarkChunk* old_chunk = _current_read_chunk;
95 _current_read_chunk = old_chunk->_next;
96
97 if (old_chunk == _current_write_chunk) {
98 assert(_current_read_chunk == NULL, "we are deleting the last chunk");
99 _current_write_chunk = NULL;
100 }
101
102 delete old_chunk;
103 }
104
105 return entry;
106 }
107
108 /////////////// Unit tests ///////////////
109
110 #ifndef PRODUCT
111
112 void g1PreserveMarkChunkTests() {
113 const int chunk_size = 5;
114
115 G1PreserveMarkChunk* chunk = new G1PreserveMarkChunk(chunk_size);
116
117 assert(!chunk->is_full(), "");
118 assert(!chunk->has_data(), "");
119
120 for (int i = 0; i < chunk_size; i++) {
121 G1PreserveMarkQueueEntry entry = {(oop)i, (markOop)(chunk_size - i)};
122 chunk->append(entry);
123 }
124
125 assert(chunk->is_full(), "");
126 assert(chunk->has_data(), "");
127
128 for (int i = 0; i < chunk_size; i++) {
129 assert(chunk->has_data(), "");
130 G1PreserveMarkQueueEntry entry = chunk->remove_first();
131 assert((oop)i == entry.obj, "");
132 assert((markOop)(chunk_size - i) == entry.mark, "");
133 }
134
135 assert(chunk->is_full(), "");
136 assert(!chunk->has_data(), "");
137
138 delete chunk;
139 }
140
141 void G1PreserveMarkQueue::verify_empty() {
142 assert(_current_write_chunk == NULL, "_current_write_chunk not null");
143 assert(_current_read_chunk == NULL, "_current_read_chunk not null");
144 }
145
146 void g1PreserveMarkQueueUse(G1PreserveMarkQueue& queue) {
147 assert(!queue.has_data(), "");
148
149 const int num_entries = 51;
150 for (int i = 0; i < num_entries; i++) {
151 queue.append((oop)i, (markOop)(num_entries - i));
152 }
153
154 assert(queue.has_data(), "");
155
156 for (int i = 0; i < num_entries; i++) {
157 assert(queue.has_data(), "");
158 G1PreserveMarkQueueEntry entry = queue.remove_first();
159 assert((oop)i == entry.obj, err_msg("wrong data (" PTR_FORMAT ") at index %d", (oopDesc*)(entry.obj), i));
160 assert((markOop)(num_entries - i) == entry.mark, err_msg("wrong data (" PTR_FORMAT ") at index %d", entry.mark, i));
161 }
162
163 assert(!queue.has_data(), "");
164
165 queue.verify_empty();
166 }
167
168 void g1PreserveMarkQueueTestOneUse() {
169 G1PreserveMarkQueue queue(5, 10);
170 g1PreserveMarkQueueUse(queue);
171 }
172
173
174 void g1PreserveMarkQueueTestMultiUse() {
175 G1PreserveMarkQueue queue(5, 10);
176 g1PreserveMarkQueueUse(queue);
177 g1PreserveMarkQueueUse(queue);
178 g1PreserveMarkQueueUse(queue);
179 }
180
181 void g1PreserveMarkQueueTests() {
182 g1PreserveMarkQueueTestOneUse();
183 g1PreserveMarkQueueTestMultiUse();
184 }
185
186 #endif
187
188