0
|
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 # include "incls/_precompiled.incl"
|
|
26 # include "incls/_freeList.cpp.incl"
|
|
27
|
|
28 // Free list. A FreeList is used to access a linked list of chunks
|
|
29 // of space in the heap. The head and tail are maintained so that
|
|
30 // items can be (as in the current implementation) added at the
|
|
31 // at the tail of the list and removed from the head of the list to
|
|
32 // maintain a FIFO queue.
|
|
33
|
|
34 FreeList::FreeList() :
|
|
35 _head(NULL), _tail(NULL)
|
|
36 #ifdef ASSERT
|
|
37 , _protecting_lock(NULL)
|
|
38 #endif
|
|
39 {
|
|
40 _size = 0;
|
|
41 _count = 0;
|
|
42 _hint = 0;
|
|
43 init_statistics();
|
|
44 }
|
|
45
|
|
46 FreeList::FreeList(FreeChunk* fc) :
|
|
47 _head(fc), _tail(fc)
|
|
48 #ifdef ASSERT
|
|
49 , _protecting_lock(NULL)
|
|
50 #endif
|
|
51 {
|
|
52 _size = fc->size();
|
|
53 _count = 1;
|
|
54 _hint = 0;
|
|
55 init_statistics();
|
|
56 #ifndef PRODUCT
|
|
57 _allocation_stats.set_returnedBytes(size() * HeapWordSize);
|
|
58 #endif
|
|
59 }
|
|
60
|
|
61 FreeList::FreeList(HeapWord* addr, size_t size) :
|
|
62 _head((FreeChunk*) addr), _tail((FreeChunk*) addr)
|
|
63 #ifdef ASSERT
|
|
64 , _protecting_lock(NULL)
|
|
65 #endif
|
|
66 {
|
|
67 assert(size > sizeof(FreeChunk), "size is too small");
|
|
68 head()->setSize(size);
|
|
69 _size = size;
|
|
70 _count = 1;
|
|
71 init_statistics();
|
|
72 #ifndef PRODUCT
|
|
73 _allocation_stats.set_returnedBytes(_size * HeapWordSize);
|
|
74 #endif
|
|
75 }
|
|
76
|
|
77 void FreeList::reset(size_t hint) {
|
|
78 set_count(0);
|
|
79 set_head(NULL);
|
|
80 set_tail(NULL);
|
|
81 set_hint(hint);
|
|
82 }
|
|
83
|
|
84 void FreeList::init_statistics() {
|
|
85 _allocation_stats.initialize();
|
|
86 }
|
|
87
|
|
88 FreeChunk* FreeList::getChunkAtHead() {
|
|
89 assert_proper_lock_protection();
|
|
90 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
91 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
92 FreeChunk* fc = head();
|
|
93 if (fc != NULL) {
|
|
94 FreeChunk* nextFC = fc->next();
|
|
95 if (nextFC != NULL) {
|
|
96 // The chunk fc being removed has a "next". Set the "next" to the
|
|
97 // "prev" of fc.
|
|
98 nextFC->linkPrev(NULL);
|
|
99 } else { // removed tail of list
|
|
100 link_tail(NULL);
|
|
101 }
|
|
102 link_head(nextFC);
|
|
103 decrement_count();
|
|
104 }
|
|
105 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
106 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
107 return fc;
|
|
108 }
|
|
109
|
|
110
|
|
111 void FreeList::getFirstNChunksFromList(size_t n, FreeList* fl) {
|
|
112 assert_proper_lock_protection();
|
|
113 assert(fl->count() == 0, "Precondition");
|
|
114 if (count() > 0) {
|
|
115 int k = 1;
|
|
116 fl->set_head(head()); n--;
|
|
117 FreeChunk* tl = head();
|
|
118 while (tl->next() != NULL && n > 0) {
|
|
119 tl = tl->next(); n--; k++;
|
|
120 }
|
|
121 assert(tl != NULL, "Loop Inv.");
|
|
122
|
|
123 // First, fix up the list we took from.
|
|
124 FreeChunk* new_head = tl->next();
|
|
125 set_head(new_head);
|
|
126 set_count(count() - k);
|
|
127 if (new_head == NULL) {
|
|
128 set_tail(NULL);
|
|
129 } else {
|
|
130 new_head->linkPrev(NULL);
|
|
131 }
|
|
132 // Now we can fix up the tail.
|
|
133 tl->linkNext(NULL);
|
|
134 // And return the result.
|
|
135 fl->set_tail(tl);
|
|
136 fl->set_count(k);
|
|
137 }
|
|
138 }
|
|
139
|
|
140 // Remove this chunk from the list
|
|
141 void FreeList::removeChunk(FreeChunk*fc) {
|
|
142 assert_proper_lock_protection();
|
|
143 assert(head() != NULL, "Remove from empty list");
|
|
144 assert(fc != NULL, "Remove a NULL chunk");
|
|
145 assert(size() == fc->size(), "Wrong list");
|
|
146 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
147 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
148
|
|
149 FreeChunk* prevFC = fc->prev();
|
|
150 FreeChunk* nextFC = fc->next();
|
|
151 if (nextFC != NULL) {
|
|
152 // The chunk fc being removed has a "next". Set the "next" to the
|
|
153 // "prev" of fc.
|
|
154 nextFC->linkPrev(prevFC);
|
|
155 } else { // removed tail of list
|
|
156 link_tail(prevFC);
|
|
157 }
|
|
158 if (prevFC == NULL) { // removed head of list
|
|
159 link_head(nextFC);
|
|
160 assert(nextFC == NULL || nextFC->prev() == NULL,
|
|
161 "Prev of head should be NULL");
|
|
162 } else {
|
|
163 prevFC->linkNext(nextFC);
|
|
164 assert(tail() != prevFC || prevFC->next() == NULL,
|
|
165 "Next of tail should be NULL");
|
|
166 }
|
|
167 decrement_count();
|
|
168 #define TRAP_CODE 1
|
|
169 #if TRAP_CODE
|
|
170 if (head() == NULL) {
|
|
171 guarantee(tail() == NULL, "INVARIANT");
|
|
172 guarantee(count() == 0, "INVARIANT");
|
|
173 }
|
|
174 #endif
|
|
175 // clear next and prev fields of fc, debug only
|
|
176 NOT_PRODUCT(
|
|
177 fc->linkPrev(NULL);
|
|
178 fc->linkNext(NULL);
|
|
179 )
|
|
180 assert(fc->isFree(), "Should still be a free chunk");
|
|
181 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
182 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
183 assert(head() == NULL || head()->size() == size(), "wrong item on list");
|
|
184 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
|
|
185 }
|
|
186
|
|
187 // Add this chunk at the head of the list.
|
|
188 void FreeList::returnChunkAtHead(FreeChunk* chunk, bool record_return) {
|
|
189 assert_proper_lock_protection();
|
|
190 assert(chunk != NULL, "insert a NULL chunk");
|
|
191 assert(size() == chunk->size(), "Wrong size");
|
|
192 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
193 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
194
|
|
195 FreeChunk* oldHead = head();
|
|
196 assert(chunk != oldHead, "double insertion");
|
|
197 chunk->linkAfter(oldHead);
|
|
198 link_head(chunk);
|
|
199 if (oldHead == NULL) { // only chunk in list
|
|
200 assert(tail() == NULL, "inconsistent FreeList");
|
|
201 link_tail(chunk);
|
|
202 }
|
|
203 increment_count(); // of # of chunks in list
|
|
204 DEBUG_ONLY(
|
|
205 if (record_return) {
|
|
206 increment_returnedBytes_by(size()*HeapWordSize);
|
|
207 }
|
|
208 )
|
|
209 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
210 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
211 assert(head() == NULL || head()->size() == size(), "wrong item on list");
|
|
212 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
|
|
213 }
|
|
214
|
|
215 void FreeList::returnChunkAtHead(FreeChunk* chunk) {
|
|
216 assert_proper_lock_protection();
|
|
217 returnChunkAtHead(chunk, true);
|
|
218 }
|
|
219
|
|
220 // Add this chunk at the tail of the list.
|
|
221 void FreeList::returnChunkAtTail(FreeChunk* chunk, bool record_return) {
|
|
222 assert_proper_lock_protection();
|
|
223 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
224 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
225 assert(chunk != NULL, "insert a NULL chunk");
|
|
226 assert(size() == chunk->size(), "wrong size");
|
|
227
|
|
228 FreeChunk* oldTail = tail();
|
|
229 assert(chunk != oldTail, "double insertion");
|
|
230 if (oldTail != NULL) {
|
|
231 oldTail->linkAfter(chunk);
|
|
232 } else { // only chunk in list
|
|
233 assert(head() == NULL, "inconsistent FreeList");
|
|
234 link_head(chunk);
|
|
235 }
|
|
236 link_tail(chunk);
|
|
237 increment_count(); // of # of chunks in list
|
|
238 DEBUG_ONLY(
|
|
239 if (record_return) {
|
|
240 increment_returnedBytes_by(size()*HeapWordSize);
|
|
241 }
|
|
242 )
|
|
243 assert(head() == NULL || head()->prev() == NULL, "list invariant");
|
|
244 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
|
|
245 assert(head() == NULL || head()->size() == size(), "wrong item on list");
|
|
246 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
|
|
247 }
|
|
248
|
|
249 void FreeList::returnChunkAtTail(FreeChunk* chunk) {
|
|
250 returnChunkAtTail(chunk, true);
|
|
251 }
|
|
252
|
|
253 void FreeList::prepend(FreeList* fl) {
|
|
254 assert_proper_lock_protection();
|
|
255 if (fl->count() > 0) {
|
|
256 if (count() == 0) {
|
|
257 set_head(fl->head());
|
|
258 set_tail(fl->tail());
|
|
259 set_count(fl->count());
|
|
260 } else {
|
|
261 // Both are non-empty.
|
|
262 FreeChunk* fl_tail = fl->tail();
|
|
263 FreeChunk* this_head = head();
|
|
264 assert(fl_tail->next() == NULL, "Well-formedness of fl");
|
|
265 fl_tail->linkNext(this_head);
|
|
266 this_head->linkPrev(fl_tail);
|
|
267 set_head(fl->head());
|
|
268 set_count(count() + fl->count());
|
|
269 }
|
|
270 fl->set_head(NULL);
|
|
271 fl->set_tail(NULL);
|
|
272 fl->set_count(0);
|
|
273 }
|
|
274 }
|
|
275
|
|
276 // verifyChunkInFreeLists() is used to verify that an item is in this free list.
|
|
277 // It is used as a debugging aid.
|
|
278 bool FreeList::verifyChunkInFreeLists(FreeChunk* fc) const {
|
|
279 // This is an internal consistency check, not part of the check that the
|
|
280 // chunk is in the free lists.
|
|
281 guarantee(fc->size() == size(), "Wrong list is being searched");
|
|
282 FreeChunk* curFC = head();
|
|
283 while (curFC) {
|
|
284 // This is an internal consistency check.
|
|
285 guarantee(size() == curFC->size(), "Chunk is in wrong list.");
|
|
286 if (fc == curFC) {
|
|
287 return true;
|
|
288 }
|
|
289 curFC = curFC->next();
|
|
290 }
|
|
291 return false;
|
|
292 }
|
|
293
|
|
294 #ifndef PRODUCT
|
|
295 void FreeList::assert_proper_lock_protection_work() const {
|
|
296 #ifdef ASSERT
|
|
297 if (_protecting_lock != NULL &&
|
|
298 SharedHeap::heap()->n_par_threads() > 0) {
|
|
299 // Should become an assert.
|
|
300 guarantee(_protecting_lock->owned_by_self(), "FreeList RACE DETECTED");
|
|
301 }
|
|
302 #endif
|
|
303 }
|
|
304 #endif
|