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/g1PreservedMarksQueue.hpp"
27 #include "memory/allocation.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "oops/oopsHierarchy.hpp"
30
31 class G1PreservedMarksChunk : public ResourceObj {
32 const size_t _capacity;
33 size_t _write_index;
34 size_t _read_index;
35 G1PreservedMarksQueueEntry* _data;
36
37 public:
38 G1PreservedMarksChunk(size_t capacity) : _capacity(capacity), _write_index(0), _read_index(0), _next(NULL) {
39 _data = NEW_C_HEAP_ARRAY(G1PreservedMarksQueueEntry, _capacity, mtGC);
40 }
41
42 ~G1PreservedMarksChunk() {
43 FREE_C_HEAP_ARRAY(G1PreservedMarksQueueEntry, _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 G1PreservedMarksQueueEntry& entry) {
56 assert(!is_full(), "overflow");
57 _data[_write_index++] = entry;
58 }
59
60 G1PreservedMarksQueueEntry remove_first() {
61 assert(has_data(), "empty");
62 return _data[_read_index++];
63 }
64
65 G1PreservedMarksChunk* _next;
66 };
67
68 bool G1PreservedMarksQueue::has_data() {
69 return _current_read_chunk != NULL && _current_read_chunk->has_data();
70 }
71
72 size_t G1PreservedMarksQueue::new_chunk_capacity() {
73 if (_current_write_chunk == NULL) {
74 _current_capacity = _initial_chunk_capacity;
75 } else if (_current_capacity == _max_chunk_capacity) {
76 // do nothing. already at max capacity
77 } else {
78 // Grow with 50%, similar to java.util.ArrayList
79 _current_capacity += _current_capacity >> 1;
80 _current_capacity = MIN2(_current_capacity, _max_chunk_capacity);
81 }
82
83 assert(_current_capacity >= _initial_chunk_capacity, "too small capacity"); assert(_current_capacity <= _max_chunk_capacity, "too large capacity");
84
85 return _current_capacity;
86 }
87
88 G1PreservedMarksChunk* G1PreservedMarksQueue::new_chunk() {
89 return new (ResourceObj::C_HEAP, mtGC) G1PreservedMarksChunk(new_chunk_capacity());
90 }
91
92 void G1PreservedMarksQueue::append(const oop& obj, const markOop& mark) {
93 G1PreservedMarksQueueEntry entry = {obj, mark};
94 if (_current_write_chunk == NULL) {
95 assert(_current_read_chunk == NULL, "must be");
96 _current_write_chunk = new_chunk();
97 _current_read_chunk = _current_write_chunk;
98 } else if (_current_write_chunk->is_full()) {
99 G1PreservedMarksChunk* current_chunk = new_chunk();
100 _current_write_chunk->_next = current_chunk;
101 _current_write_chunk = current_chunk;
102 }
103
104 assert(!_current_write_chunk->is_full(), "full");
105
106 _current_write_chunk->append(entry);
107 }
108
109 G1PreservedMarksQueueEntry G1PreservedMarksQueue::remove_first() {
110 assert(has_data(), "empty");
111 G1PreservedMarksQueueEntry entry = _current_read_chunk->remove_first();
112
113 if (!_current_read_chunk->has_data()) {
114 G1PreservedMarksChunk* old_chunk = _current_read_chunk;
115 _current_read_chunk = old_chunk->_next;
116
117 if (old_chunk == _current_write_chunk) {
118 assert(_current_read_chunk == NULL, "we are deleting the last chunk");
119 _current_write_chunk = NULL;
120 }
121
122 delete old_chunk;
123 }
124
125 return entry;
126 }
127
128 /////////////// Unit tests ///////////////
129
130 #ifndef PRODUCT
131
132 void g1PreservedMarksChunkTests() {
133 const int chunk_size = 5;
134
135 G1PreservedMarksChunk* chunk = new (ResourceObj::C_HEAP, mtGC) G1PreservedMarksChunk(chunk_size);
136
137 assert(!chunk->is_full(), "");
138 assert(!chunk->has_data(), "");
139
140 for (int i = 0; i < chunk_size; i++) {
141 G1PreservedMarksQueueEntry entry = {(oop)i, (markOop)(chunk_size - i)};
142 chunk->append(entry);
143 }
144
145 assert(chunk->is_full(), "");
146 assert(chunk->has_data(), "");
147
148 for (int i = 0; i < chunk_size; i++) {
149 assert(chunk->has_data(), "");
150 G1PreservedMarksQueueEntry entry = chunk->remove_first();
151 assert((oop)i == entry.obj, "");
152 assert((markOop)(chunk_size - i) == entry.mark, "");
153 }
154
155 assert(chunk->is_full(), "");
156 assert(!chunk->has_data(), "");
157
158 delete chunk;
159 }
160
161 void G1PreservedMarksQueue::verify_empty() {
162 assert(_current_write_chunk == NULL, "_current_write_chunk not null");
163 assert(_current_read_chunk == NULL, "_current_read_chunk not null");
164 }
165
166 void g1PreserveMarkQueueUse(G1PreservedMarksQueue& queue) {
167 assert(!queue.has_data(), "");
168
169 const int num_entries = 51;
170 for (int i = 0; i < num_entries; i++) {
171 queue.append((oop)i, (markOop)(num_entries - i));
172 }
173
174 assert(queue.has_data(), "");
175
176 for (int i = 0; i < num_entries; i++) {
177 assert(queue.has_data(), "");
178 G1PreservedMarksQueueEntry entry = queue.remove_first();
179 assert((oop)i == entry.obj, err_msg("wrong data (" PTR_FORMAT ") at index %d", (oopDesc*)(entry.obj), i));
180 assert((markOop)(num_entries - i) == entry.mark, err_msg("wrong data (" PTR_FORMAT ") at index %d", entry.mark, i));
181 }
182
183 assert(!queue.has_data(), "");
184
185 queue.verify_empty();
186 }
187
188 void g1PreserveMarkQueueTestOneUse() {
189 G1PreservedMarksQueue queue(5, 10);
190 g1PreserveMarkQueueUse(queue);
191 }
192
193
194 void g1PreserveMarkQueueTestMultiUse() {
195 G1PreservedMarksQueue queue(5, 10);
196 g1PreserveMarkQueueUse(queue);
197 g1PreserveMarkQueueUse(queue);
198 g1PreserveMarkQueueUse(queue);
199 }
200
201 void g1PreservedMarksQueueTests() {
202 g1PreserveMarkQueueTestOneUse();
203 g1PreserveMarkQueueTestMultiUse();
204 }
205
206 #endif
207
208