Fri, 01 Feb 2013 23:48:08 +0100
8005012: Add WB APIs to better support NMT testing
Summary: Add WB API functions to enable better NMT testing
Reviewed-by: dholmes, zgu
1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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).
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23 */
25 #include "precompiled.hpp"
26 #include "memory/freeBlockDictionary.hpp"
27 #include "memory/freeList.hpp"
28 #include "memory/metablock.hpp"
29 #include "memory/metachunk.hpp"
30 #include "memory/sharedHeap.hpp"
31 #include "runtime/globals.hpp"
32 #include "runtime/mutex.hpp"
33 #include "runtime/vmThread.hpp"
35 #ifndef SERIALGC
36 #include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
37 #endif // SERIALGC
39 // Free list. A FreeList is used to access a linked list of chunks
40 // of space in the heap. The head and tail are maintained so that
41 // items can be (as in the current implementation) added at the
42 // at the tail of the list and removed from the head of the list to
43 // maintain a FIFO queue.
45 template <class Chunk>
46 FreeList<Chunk>::FreeList() :
47 _head(NULL), _tail(NULL)
48 #ifdef ASSERT
49 , _protecting_lock(NULL)
50 #endif
51 {
52 _size = 0;
53 _count = 0;
54 }
56 template <class Chunk>
57 FreeList<Chunk>::FreeList(Chunk* fc) :
58 _head(fc), _tail(fc)
59 #ifdef ASSERT
60 , _protecting_lock(NULL)
61 #endif
62 {
63 _size = fc->size();
64 _count = 1;
65 }
67 template <class Chunk>
68 void FreeList<Chunk>::link_head(Chunk* v) {
69 assert_proper_lock_protection();
70 set_head(v);
71 // If this method is not used (just set the head instead),
72 // this check can be avoided.
73 if (v != NULL) {
74 v->link_prev(NULL);
75 }
76 }
80 template <class Chunk>
81 void FreeList<Chunk>::reset() {
82 // Don't set the _size to 0 because this method is
83 // used with a existing list that has a size but which has
84 // been emptied.
85 // Don't clear the _protecting_lock of an existing list.
86 set_count(0);
87 set_head(NULL);
88 set_tail(NULL);
89 }
91 template <class Chunk>
92 void FreeList<Chunk>::initialize() {
93 #ifdef ASSERT
94 // Needed early because it might be checked in other initializing code.
95 set_protecting_lock(NULL);
96 #endif
97 reset();
98 set_size(0);
99 }
101 template <class Chunk_t>
102 Chunk_t* FreeList<Chunk_t>::get_chunk_at_head() {
103 assert_proper_lock_protection();
104 assert(head() == NULL || head()->prev() == NULL, "list invariant");
105 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
106 Chunk_t* fc = head();
107 if (fc != NULL) {
108 Chunk_t* nextFC = fc->next();
109 if (nextFC != NULL) {
110 // The chunk fc being removed has a "next". Set the "next" to the
111 // "prev" of fc.
112 nextFC->link_prev(NULL);
113 } else { // removed tail of list
114 link_tail(NULL);
115 }
116 link_head(nextFC);
117 decrement_count();
118 }
119 assert(head() == NULL || head()->prev() == NULL, "list invariant");
120 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
121 return fc;
122 }
125 template <class Chunk>
126 void FreeList<Chunk>::getFirstNChunksFromList(size_t n, FreeList<Chunk>* fl) {
127 assert_proper_lock_protection();
128 assert(fl->count() == 0, "Precondition");
129 if (count() > 0) {
130 int k = 1;
131 fl->set_head(head()); n--;
132 Chunk* tl = head();
133 while (tl->next() != NULL && n > 0) {
134 tl = tl->next(); n--; k++;
135 }
136 assert(tl != NULL, "Loop Inv.");
138 // First, fix up the list we took from.
139 Chunk* new_head = tl->next();
140 set_head(new_head);
141 set_count(count() - k);
142 if (new_head == NULL) {
143 set_tail(NULL);
144 } else {
145 new_head->link_prev(NULL);
146 }
147 // Now we can fix up the tail.
148 tl->link_next(NULL);
149 // And return the result.
150 fl->set_tail(tl);
151 fl->set_count(k);
152 }
153 }
155 // Remove this chunk from the list
156 template <class Chunk>
157 void FreeList<Chunk>::remove_chunk(Chunk*fc) {
158 assert_proper_lock_protection();
159 assert(head() != NULL, "Remove from empty list");
160 assert(fc != NULL, "Remove a NULL chunk");
161 assert(size() == fc->size(), "Wrong list");
162 assert(head() == NULL || head()->prev() == NULL, "list invariant");
163 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
165 Chunk* prevFC = fc->prev();
166 Chunk* nextFC = fc->next();
167 if (nextFC != NULL) {
168 // The chunk fc being removed has a "next". Set the "next" to the
169 // "prev" of fc.
170 nextFC->link_prev(prevFC);
171 } else { // removed tail of list
172 link_tail(prevFC);
173 }
174 if (prevFC == NULL) { // removed head of list
175 link_head(nextFC);
176 assert(nextFC == NULL || nextFC->prev() == NULL,
177 "Prev of head should be NULL");
178 } else {
179 prevFC->link_next(nextFC);
180 assert(tail() != prevFC || prevFC->next() == NULL,
181 "Next of tail should be NULL");
182 }
183 decrement_count();
184 assert(((head() == NULL) + (tail() == NULL) + (count() == 0)) % 3 == 0,
185 "H/T/C Inconsistency");
186 // clear next and prev fields of fc, debug only
187 NOT_PRODUCT(
188 fc->link_prev(NULL);
189 fc->link_next(NULL);
190 )
191 assert(fc->is_free(), "Should still be a free chunk");
192 assert(head() == NULL || head()->prev() == NULL, "list invariant");
193 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
194 assert(head() == NULL || head()->size() == size(), "wrong item on list");
195 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
196 }
198 // Add this chunk at the head of the list.
199 template <class Chunk>
200 void FreeList<Chunk>::return_chunk_at_head(Chunk* chunk, bool record_return) {
201 assert_proper_lock_protection();
202 assert(chunk != NULL, "insert a NULL chunk");
203 assert(size() == chunk->size(), "Wrong size");
204 assert(head() == NULL || head()->prev() == NULL, "list invariant");
205 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
207 Chunk* oldHead = head();
208 assert(chunk != oldHead, "double insertion");
209 chunk->link_after(oldHead);
210 link_head(chunk);
211 if (oldHead == NULL) { // only chunk in list
212 assert(tail() == NULL, "inconsistent FreeList");
213 link_tail(chunk);
214 }
215 increment_count(); // of # of chunks in list
216 assert(head() == NULL || head()->prev() == NULL, "list invariant");
217 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
218 assert(head() == NULL || head()->size() == size(), "wrong item on list");
219 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
220 }
222 template <class Chunk>
223 void FreeList<Chunk>::return_chunk_at_head(Chunk* chunk) {
224 assert_proper_lock_protection();
225 return_chunk_at_head(chunk, true);
226 }
228 // Add this chunk at the tail of the list.
229 template <class Chunk>
230 void FreeList<Chunk>::return_chunk_at_tail(Chunk* chunk, bool record_return) {
231 assert_proper_lock_protection();
232 assert(head() == NULL || head()->prev() == NULL, "list invariant");
233 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
234 assert(chunk != NULL, "insert a NULL chunk");
235 assert(size() == chunk->size(), "wrong size");
237 Chunk* oldTail = tail();
238 assert(chunk != oldTail, "double insertion");
239 if (oldTail != NULL) {
240 oldTail->link_after(chunk);
241 } else { // only chunk in list
242 assert(head() == NULL, "inconsistent FreeList");
243 link_head(chunk);
244 }
245 link_tail(chunk);
246 increment_count(); // of # of chunks in list
247 assert(head() == NULL || head()->prev() == NULL, "list invariant");
248 assert(tail() == NULL || tail()->next() == NULL, "list invariant");
249 assert(head() == NULL || head()->size() == size(), "wrong item on list");
250 assert(tail() == NULL || tail()->size() == size(), "wrong item on list");
251 }
253 template <class Chunk>
254 void FreeList<Chunk>::return_chunk_at_tail(Chunk* chunk) {
255 return_chunk_at_tail(chunk, true);
256 }
258 template <class Chunk>
259 void FreeList<Chunk>::prepend(FreeList<Chunk>* fl) {
260 assert_proper_lock_protection();
261 if (fl->count() > 0) {
262 if (count() == 0) {
263 set_head(fl->head());
264 set_tail(fl->tail());
265 set_count(fl->count());
266 } else {
267 // Both are non-empty.
268 Chunk* fl_tail = fl->tail();
269 Chunk* this_head = head();
270 assert(fl_tail->next() == NULL, "Well-formedness of fl");
271 fl_tail->link_next(this_head);
272 this_head->link_prev(fl_tail);
273 set_head(fl->head());
274 set_count(count() + fl->count());
275 }
276 fl->set_head(NULL);
277 fl->set_tail(NULL);
278 fl->set_count(0);
279 }
280 }
282 // verify_chunk_in_free_lists() is used to verify that an item is in this free list.
283 // It is used as a debugging aid.
284 template <class Chunk>
285 bool FreeList<Chunk>::verify_chunk_in_free_list(Chunk* fc) const {
286 // This is an internal consistency check, not part of the check that the
287 // chunk is in the free lists.
288 guarantee(fc->size() == size(), "Wrong list is being searched");
289 Chunk* curFC = head();
290 while (curFC) {
291 // This is an internal consistency check.
292 guarantee(size() == curFC->size(), "Chunk is in wrong list.");
293 if (fc == curFC) {
294 return true;
295 }
296 curFC = curFC->next();
297 }
298 return false;
299 }
301 #ifndef PRODUCT
302 template <class Chunk>
303 void FreeList<Chunk>::assert_proper_lock_protection_work() const {
304 assert(protecting_lock() != NULL, "Don't call this directly");
305 assert(ParallelGCThreads > 0, "Don't call this directly");
306 Thread* thr = Thread::current();
307 if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) {
308 // assert that we are holding the freelist lock
309 } else if (thr->is_GC_task_thread()) {
310 assert(protecting_lock()->owned_by_self(), "FreeList RACE DETECTED");
311 } else if (thr->is_Java_thread()) {
312 assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing");
313 } else {
314 ShouldNotReachHere(); // unaccounted thread type?
315 }
316 }
317 #endif
319 // Print the "label line" for free list stats.
320 template <class Chunk>
321 void FreeList<Chunk>::print_labels_on(outputStream* st, const char* c) {
322 st->print("%16s\t", c);
323 st->print("%14s\t" "%14s\t" "%14s\t" "%14s\t" "%14s\t"
324 "%14s\t" "%14s\t" "%14s\t" "%14s\t" "%14s\t" "\n",
325 "bfrsurp", "surplus", "desired", "prvSwep", "bfrSwep",
326 "count", "cBirths", "cDeaths", "sBirths", "sDeaths");
327 }
329 // Print the AllocationStats for the given free list. If the second argument
330 // to the call is a non-null string, it is printed in the first column;
331 // otherwise, if the argument is null (the default), then the size of the
332 // (free list) block is printed in the first column.
333 template <class Chunk_t>
334 void FreeList<Chunk_t>::print_on(outputStream* st, const char* c) const {
335 if (c != NULL) {
336 st->print("%16s", c);
337 } else {
338 st->print(SIZE_FORMAT_W(16), size());
339 }
340 }
342 template class FreeList<Metablock>;
343 template class FreeList<Metachunk>;
344 #ifndef SERIALGC
345 template class FreeList<FreeChunk>;
346 #endif // SERIALGC