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comparison src/share/vm/gc_implementation/concurrentMarkSweep/freeList.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 6432c3bb6240 |
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1 /* | |
2 * Copyright 2001-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 class CompactibleFreeListSpace; | |
26 | |
27 // A class for maintaining a free list of FreeChunk's. The FreeList | |
28 // maintains a the structure of the list (head, tail, etc.) plus | |
29 // statistics for allocations from the list. The links between items | |
30 // are not part of FreeList. The statistics are | |
31 // used to make decisions about coalescing FreeChunk's when they | |
32 // are swept during collection. | |
33 // | |
34 // See the corresponding .cpp file for a description of the specifics | |
35 // for that implementation. | |
36 | |
37 class Mutex; | |
38 | |
39 class FreeList VALUE_OBJ_CLASS_SPEC { | |
40 friend class CompactibleFreeListSpace; | |
41 FreeChunk* _head; // List of free chunks | |
42 FreeChunk* _tail; // Tail of list of free chunks | |
43 size_t _size; // Size in Heap words of each chunks | |
44 ssize_t _count; // Number of entries in list | |
45 size_t _hint; // next larger size list with a positive surplus | |
46 | |
47 AllocationStats _allocation_stats; // statistics for smart allocation | |
48 | |
49 #ifdef ASSERT | |
50 Mutex* _protecting_lock; | |
51 #endif | |
52 | |
53 // Asserts false if the protecting lock (if any) is not held. | |
54 void assert_proper_lock_protection_work() const PRODUCT_RETURN; | |
55 void assert_proper_lock_protection() const { | |
56 #ifdef ASSERT | |
57 if (_protecting_lock != NULL) | |
58 assert_proper_lock_protection_work(); | |
59 #endif | |
60 } | |
61 | |
62 // Initialize the allocation statistics. | |
63 protected: | |
64 void init_statistics(); | |
65 void set_count(ssize_t v) { _count = v;} | |
66 void increment_count() { _count++; } | |
67 void decrement_count() { | |
68 _count--; | |
69 assert(_count >= 0, "Count should not be negative"); } | |
70 | |
71 public: | |
72 // Constructor | |
73 // Construct a list without any entries. | |
74 FreeList(); | |
75 // Construct a list with "fc" as the first (and lone) entry in the list. | |
76 FreeList(FreeChunk* fc); | |
77 // Construct a list which will have a FreeChunk at address "addr" and | |
78 // of size "size" as the first (and lone) entry in the list. | |
79 FreeList(HeapWord* addr, size_t size); | |
80 | |
81 // Reset the head, tail, hint, and count of a free list. | |
82 void reset(size_t hint); | |
83 | |
84 // Declare the current free list to be protected by the given lock. | |
85 #ifdef ASSERT | |
86 void set_protecting_lock(Mutex* protecting_lock) { | |
87 _protecting_lock = protecting_lock; | |
88 } | |
89 #endif | |
90 | |
91 // Accessors. | |
92 FreeChunk* head() const { | |
93 assert_proper_lock_protection(); | |
94 return _head; | |
95 } | |
96 void set_head(FreeChunk* v) { | |
97 assert_proper_lock_protection(); | |
98 _head = v; | |
99 assert(!_head || _head->size() == _size, "bad chunk size"); | |
100 } | |
101 // Set the head of the list and set the prev field of non-null | |
102 // values to NULL. | |
103 void link_head(FreeChunk* v) { | |
104 assert_proper_lock_protection(); | |
105 set_head(v); | |
106 // If this method is not used (just set the head instead), | |
107 // this check can be avoided. | |
108 if (v != NULL) { | |
109 v->linkPrev(NULL); | |
110 } | |
111 } | |
112 | |
113 FreeChunk* tail() const { | |
114 assert_proper_lock_protection(); | |
115 return _tail; | |
116 } | |
117 void set_tail(FreeChunk* v) { | |
118 assert_proper_lock_protection(); | |
119 _tail = v; | |
120 assert(!_tail || _tail->size() == _size, "bad chunk size"); | |
121 } | |
122 // Set the tail of the list and set the next field of non-null | |
123 // values to NULL. | |
124 void link_tail(FreeChunk* v) { | |
125 assert_proper_lock_protection(); | |
126 set_tail(v); | |
127 if (v != NULL) { | |
128 v->clearNext(); | |
129 } | |
130 } | |
131 | |
132 // No locking checks in read-accessors: lock-free reads (only) are benign. | |
133 // Readers are expected to have the lock if they are doing work that | |
134 // requires atomicity guarantees in sections of code. | |
135 size_t size() const { | |
136 return _size; | |
137 } | |
138 void set_size(size_t v) { | |
139 assert_proper_lock_protection(); | |
140 _size = v; | |
141 } | |
142 ssize_t count() const { | |
143 return _count; | |
144 } | |
145 size_t hint() const { | |
146 return _hint; | |
147 } | |
148 void set_hint(size_t v) { | |
149 assert_proper_lock_protection(); | |
150 assert(v == 0 || _size < v, "Bad hint"); _hint = v; | |
151 } | |
152 | |
153 // Accessors for statistics | |
154 AllocationStats* allocation_stats() { | |
155 assert_proper_lock_protection(); | |
156 return &_allocation_stats; | |
157 } | |
158 | |
159 ssize_t desired() const { | |
160 return _allocation_stats.desired(); | |
161 } | |
162 void compute_desired(float inter_sweep_current, | |
163 float inter_sweep_estimate) { | |
164 assert_proper_lock_protection(); | |
165 _allocation_stats.compute_desired(_count, | |
166 inter_sweep_current, | |
167 inter_sweep_estimate); | |
168 } | |
169 ssize_t coalDesired() const { | |
170 return _allocation_stats.coalDesired(); | |
171 } | |
172 void set_coalDesired(ssize_t v) { | |
173 assert_proper_lock_protection(); | |
174 _allocation_stats.set_coalDesired(v); | |
175 } | |
176 | |
177 ssize_t surplus() const { | |
178 return _allocation_stats.surplus(); | |
179 } | |
180 void set_surplus(ssize_t v) { | |
181 assert_proper_lock_protection(); | |
182 _allocation_stats.set_surplus(v); | |
183 } | |
184 void increment_surplus() { | |
185 assert_proper_lock_protection(); | |
186 _allocation_stats.increment_surplus(); | |
187 } | |
188 void decrement_surplus() { | |
189 assert_proper_lock_protection(); | |
190 _allocation_stats.decrement_surplus(); | |
191 } | |
192 | |
193 ssize_t bfrSurp() const { | |
194 return _allocation_stats.bfrSurp(); | |
195 } | |
196 void set_bfrSurp(ssize_t v) { | |
197 assert_proper_lock_protection(); | |
198 _allocation_stats.set_bfrSurp(v); | |
199 } | |
200 ssize_t prevSweep() const { | |
201 return _allocation_stats.prevSweep(); | |
202 } | |
203 void set_prevSweep(ssize_t v) { | |
204 assert_proper_lock_protection(); | |
205 _allocation_stats.set_prevSweep(v); | |
206 } | |
207 ssize_t beforeSweep() const { | |
208 return _allocation_stats.beforeSweep(); | |
209 } | |
210 void set_beforeSweep(ssize_t v) { | |
211 assert_proper_lock_protection(); | |
212 _allocation_stats.set_beforeSweep(v); | |
213 } | |
214 | |
215 ssize_t coalBirths() const { | |
216 return _allocation_stats.coalBirths(); | |
217 } | |
218 void set_coalBirths(ssize_t v) { | |
219 assert_proper_lock_protection(); | |
220 _allocation_stats.set_coalBirths(v); | |
221 } | |
222 void increment_coalBirths() { | |
223 assert_proper_lock_protection(); | |
224 _allocation_stats.increment_coalBirths(); | |
225 } | |
226 | |
227 ssize_t coalDeaths() const { | |
228 return _allocation_stats.coalDeaths(); | |
229 } | |
230 void set_coalDeaths(ssize_t v) { | |
231 assert_proper_lock_protection(); | |
232 _allocation_stats.set_coalDeaths(v); | |
233 } | |
234 void increment_coalDeaths() { | |
235 assert_proper_lock_protection(); | |
236 _allocation_stats.increment_coalDeaths(); | |
237 } | |
238 | |
239 ssize_t splitBirths() const { | |
240 return _allocation_stats.splitBirths(); | |
241 } | |
242 void set_splitBirths(ssize_t v) { | |
243 assert_proper_lock_protection(); | |
244 _allocation_stats.set_splitBirths(v); | |
245 } | |
246 void increment_splitBirths() { | |
247 assert_proper_lock_protection(); | |
248 _allocation_stats.increment_splitBirths(); | |
249 } | |
250 | |
251 ssize_t splitDeaths() const { | |
252 return _allocation_stats.splitDeaths(); | |
253 } | |
254 void set_splitDeaths(ssize_t v) { | |
255 assert_proper_lock_protection(); | |
256 _allocation_stats.set_splitDeaths(v); | |
257 } | |
258 void increment_splitDeaths() { | |
259 assert_proper_lock_protection(); | |
260 _allocation_stats.increment_splitDeaths(); | |
261 } | |
262 | |
263 NOT_PRODUCT( | |
264 // For debugging. The "_returnedBytes" in all the lists are summed | |
265 // and compared with the total number of bytes swept during a | |
266 // collection. | |
267 size_t returnedBytes() const { return _allocation_stats.returnedBytes(); } | |
268 void set_returnedBytes(size_t v) { _allocation_stats.set_returnedBytes(v); } | |
269 void increment_returnedBytes_by(size_t v) { | |
270 _allocation_stats.set_returnedBytes(_allocation_stats.returnedBytes() + v); | |
271 } | |
272 ) | |
273 | |
274 // Unlink head of list and return it. Returns NULL if | |
275 // the list is empty. | |
276 FreeChunk* getChunkAtHead(); | |
277 | |
278 // Remove the first "n" or "count", whichever is smaller, chunks from the | |
279 // list, setting "fl", which is required to be empty, to point to them. | |
280 void getFirstNChunksFromList(size_t n, FreeList* fl); | |
281 | |
282 // Unlink this chunk from it's free list | |
283 void removeChunk(FreeChunk* fc); | |
284 | |
285 // Add this chunk to this free list. | |
286 void returnChunkAtHead(FreeChunk* fc); | |
287 void returnChunkAtTail(FreeChunk* fc); | |
288 | |
289 // Similar to returnChunk* but also records some diagnostic | |
290 // information. | |
291 void returnChunkAtHead(FreeChunk* fc, bool record_return); | |
292 void returnChunkAtTail(FreeChunk* fc, bool record_return); | |
293 | |
294 // Prepend "fl" (whose size is required to be the same as that of "this") | |
295 // to the front of "this" list. | |
296 void prepend(FreeList* fl); | |
297 | |
298 // Verify that the chunk is in the list. | |
299 // found. Return NULL if "fc" is not found. | |
300 bool verifyChunkInFreeLists(FreeChunk* fc) const; | |
301 }; |