Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/parNew/parCardTableModRefBS.cpp @ 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 | df6caf649ff7 |
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1 /* | |
2 * Copyright (c) 2007 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/_parCardTableModRefBS.cpp.incl" | |
27 | |
28 void CardTableModRefBS::par_non_clean_card_iterate_work(Space* sp, MemRegion mr, | |
29 DirtyCardToOopClosure* dcto_cl, | |
30 MemRegionClosure* cl, | |
31 bool clear, | |
32 int n_threads) { | |
33 if (n_threads > 0) { | |
34 assert(n_threads == (int)ParallelGCThreads, "# worker threads != # requested!"); | |
35 | |
36 // Make sure the LNC array is valid for the space. | |
37 jbyte** lowest_non_clean; | |
38 uintptr_t lowest_non_clean_base_chunk_index; | |
39 size_t lowest_non_clean_chunk_size; | |
40 get_LNC_array_for_space(sp, lowest_non_clean, | |
41 lowest_non_clean_base_chunk_index, | |
42 lowest_non_clean_chunk_size); | |
43 | |
44 int n_strides = n_threads * StridesPerThread; | |
45 SequentialSubTasksDone* pst = sp->par_seq_tasks(); | |
46 pst->set_par_threads(n_threads); | |
47 pst->set_n_tasks(n_strides); | |
48 | |
49 int stride = 0; | |
50 while (!pst->is_task_claimed(/* reference */ stride)) { | |
51 process_stride(sp, mr, stride, n_strides, dcto_cl, cl, clear, | |
52 lowest_non_clean, | |
53 lowest_non_clean_base_chunk_index, | |
54 lowest_non_clean_chunk_size); | |
55 } | |
56 if (pst->all_tasks_completed()) { | |
57 // Clear lowest_non_clean array for next time. | |
58 intptr_t first_chunk_index = addr_to_chunk_index(mr.start()); | |
59 uintptr_t last_chunk_index = addr_to_chunk_index(mr.last()); | |
60 for (uintptr_t ch = first_chunk_index; ch <= last_chunk_index; ch++) { | |
61 intptr_t ind = ch - lowest_non_clean_base_chunk_index; | |
62 assert(0 <= ind && ind < (intptr_t)lowest_non_clean_chunk_size, | |
63 "Bounds error"); | |
64 lowest_non_clean[ind] = NULL; | |
65 } | |
66 } | |
67 } | |
68 } | |
69 | |
70 void | |
71 CardTableModRefBS:: | |
72 process_stride(Space* sp, | |
73 MemRegion used, | |
74 jint stride, int n_strides, | |
75 DirtyCardToOopClosure* dcto_cl, | |
76 MemRegionClosure* cl, | |
77 bool clear, | |
78 jbyte** lowest_non_clean, | |
79 uintptr_t lowest_non_clean_base_chunk_index, | |
80 size_t lowest_non_clean_chunk_size) { | |
81 // We don't have to go downwards here; it wouldn't help anyway, | |
82 // because of parallelism. | |
83 | |
84 // Find the first card address of the first chunk in the stride that is | |
85 // at least "bottom" of the used region. | |
86 jbyte* start_card = byte_for(used.start()); | |
87 jbyte* end_card = byte_after(used.last()); | |
88 uintptr_t start_chunk = addr_to_chunk_index(used.start()); | |
89 uintptr_t start_chunk_stride_num = start_chunk % n_strides; | |
90 jbyte* chunk_card_start; | |
91 | |
92 if ((uintptr_t)stride >= start_chunk_stride_num) { | |
93 chunk_card_start = (jbyte*)(start_card + | |
94 (stride - start_chunk_stride_num) * | |
95 CardsPerStrideChunk); | |
96 } else { | |
97 // Go ahead to the next chunk group boundary, then to the requested stride. | |
98 chunk_card_start = (jbyte*)(start_card + | |
99 (n_strides - start_chunk_stride_num + stride) * | |
100 CardsPerStrideChunk); | |
101 } | |
102 | |
103 while (chunk_card_start < end_card) { | |
104 // We don't have to go downwards here; it wouldn't help anyway, | |
105 // because of parallelism. (We take care with "min_done"; see below.) | |
106 // Invariant: chunk_mr should be fully contained within the "used" region. | |
107 jbyte* chunk_card_end = chunk_card_start + CardsPerStrideChunk; | |
108 MemRegion chunk_mr = MemRegion(addr_for(chunk_card_start), | |
109 chunk_card_end >= end_card ? | |
110 used.end() : addr_for(chunk_card_end)); | |
111 assert(chunk_mr.word_size() > 0, "[chunk_card_start > used_end)"); | |
112 assert(used.contains(chunk_mr), "chunk_mr should be subset of used"); | |
113 | |
114 // Process the chunk. | |
115 process_chunk_boundaries(sp, | |
116 dcto_cl, | |
117 chunk_mr, | |
118 used, | |
119 lowest_non_clean, | |
120 lowest_non_clean_base_chunk_index, | |
121 lowest_non_clean_chunk_size); | |
122 | |
123 non_clean_card_iterate_work(chunk_mr, cl, clear); | |
124 | |
125 // Find the next chunk of the stride. | |
126 chunk_card_start += CardsPerStrideChunk * n_strides; | |
127 } | |
128 } | |
129 | |
130 void | |
131 CardTableModRefBS:: | |
132 process_chunk_boundaries(Space* sp, | |
133 DirtyCardToOopClosure* dcto_cl, | |
134 MemRegion chunk_mr, | |
135 MemRegion used, | |
136 jbyte** lowest_non_clean, | |
137 uintptr_t lowest_non_clean_base_chunk_index, | |
138 size_t lowest_non_clean_chunk_size) | |
139 { | |
140 // We must worry about the chunk boundaries. | |
141 | |
142 // First, set our max_to_do: | |
143 HeapWord* max_to_do = NULL; | |
144 uintptr_t cur_chunk_index = addr_to_chunk_index(chunk_mr.start()); | |
145 cur_chunk_index = cur_chunk_index - lowest_non_clean_base_chunk_index; | |
146 | |
147 if (chunk_mr.end() < used.end()) { | |
148 // This is not the last chunk in the used region. What is the last | |
149 // object? | |
150 HeapWord* last_block = sp->block_start(chunk_mr.end()); | |
151 assert(last_block <= chunk_mr.end(), "In case this property changes."); | |
152 if (last_block == chunk_mr.end() | |
153 || !sp->block_is_obj(last_block)) { | |
154 max_to_do = chunk_mr.end(); | |
155 | |
156 } else { | |
157 // It is an object and starts before the end of the current chunk. | |
158 // last_obj_card is the card corresponding to the start of the last object | |
159 // in the chunk. Note that the last object may not start in | |
160 // the chunk. | |
161 jbyte* last_obj_card = byte_for(last_block); | |
162 if (!card_may_have_been_dirty(*last_obj_card)) { | |
163 // The card containing the head is not dirty. Any marks in | |
164 // subsequent cards still in this chunk must have been made | |
165 // precisely; we can cap processing at the end. | |
166 max_to_do = chunk_mr.end(); | |
167 } else { | |
168 // The last object must be considered dirty, and extends onto the | |
169 // following chunk. Look for a dirty card in that chunk that will | |
170 // bound our processing. | |
171 jbyte* limit_card = NULL; | |
172 size_t last_block_size = sp->block_size(last_block); | |
173 jbyte* last_card_of_last_obj = | |
174 byte_for(last_block + last_block_size - 1); | |
175 jbyte* first_card_of_next_chunk = byte_for(chunk_mr.end()); | |
176 // This search potentially goes a long distance looking | |
177 // for the next card that will be scanned. For example, | |
178 // an object that is an array of primitives will not | |
179 // have any cards covering regions interior to the array | |
180 // that will need to be scanned. The scan can be terminated | |
181 // at the last card of the next chunk. That would leave | |
182 // limit_card as NULL and would result in "max_to_do" | |
183 // being set with the LNC value or with the end | |
184 // of the last block. | |
185 jbyte* last_card_of_next_chunk = first_card_of_next_chunk + | |
186 CardsPerStrideChunk; | |
187 assert(byte_for(chunk_mr.end()) - byte_for(chunk_mr.start()) | |
188 == CardsPerStrideChunk, "last card of next chunk may be wrong"); | |
189 jbyte* last_card_to_check = (jbyte*) MIN2(last_card_of_last_obj, | |
190 last_card_of_next_chunk); | |
191 for (jbyte* cur = first_card_of_next_chunk; | |
192 cur <= last_card_to_check; cur++) { | |
193 if (card_will_be_scanned(*cur)) { | |
194 limit_card = cur; break; | |
195 } | |
196 } | |
197 assert(0 <= cur_chunk_index+1 && | |
198 cur_chunk_index+1 < lowest_non_clean_chunk_size, | |
199 "Bounds error."); | |
200 // LNC for the next chunk | |
201 jbyte* lnc_card = lowest_non_clean[cur_chunk_index+1]; | |
202 if (limit_card == NULL) { | |
203 limit_card = lnc_card; | |
204 } | |
205 if (limit_card != NULL) { | |
206 if (lnc_card != NULL) { | |
207 limit_card = (jbyte*)MIN2((intptr_t)limit_card, | |
208 (intptr_t)lnc_card); | |
209 } | |
210 max_to_do = addr_for(limit_card); | |
211 } else { | |
212 max_to_do = last_block + last_block_size; | |
213 } | |
214 } | |
215 } | |
216 assert(max_to_do != NULL, "OOPS!"); | |
217 } else { | |
218 max_to_do = used.end(); | |
219 } | |
220 // Now we can set the closure we're using so it doesn't to beyond | |
221 // max_to_do. | |
222 dcto_cl->set_min_done(max_to_do); | |
223 #ifndef PRODUCT | |
224 dcto_cl->set_last_bottom(max_to_do); | |
225 #endif | |
226 | |
227 // Now we set *our" lowest_non_clean entry. | |
228 // Find the object that spans our boundary, if one exists. | |
229 // Nothing to do on the first chunk. | |
230 if (chunk_mr.start() > used.start()) { | |
231 // first_block is the block possibly spanning the chunk start | |
232 HeapWord* first_block = sp->block_start(chunk_mr.start()); | |
233 // Does the block span the start of the chunk and is it | |
234 // an object? | |
235 if (first_block < chunk_mr.start() && | |
236 sp->block_is_obj(first_block)) { | |
237 jbyte* first_dirty_card = NULL; | |
238 jbyte* last_card_of_first_obj = | |
239 byte_for(first_block + sp->block_size(first_block) - 1); | |
240 jbyte* first_card_of_cur_chunk = byte_for(chunk_mr.start()); | |
241 jbyte* last_card_of_cur_chunk = byte_for(chunk_mr.last()); | |
242 jbyte* last_card_to_check = | |
243 (jbyte*) MIN2((intptr_t) last_card_of_cur_chunk, | |
244 (intptr_t) last_card_of_first_obj); | |
245 for (jbyte* cur = first_card_of_cur_chunk; | |
246 cur <= last_card_to_check; cur++) { | |
247 if (card_will_be_scanned(*cur)) { | |
248 first_dirty_card = cur; break; | |
249 } | |
250 } | |
251 if (first_dirty_card != NULL) { | |
252 assert(0 <= cur_chunk_index && | |
253 cur_chunk_index < lowest_non_clean_chunk_size, | |
254 "Bounds error."); | |
255 lowest_non_clean[cur_chunk_index] = first_dirty_card; | |
256 } | |
257 } | |
258 } | |
259 } | |
260 | |
261 void | |
262 CardTableModRefBS:: | |
263 get_LNC_array_for_space(Space* sp, | |
264 jbyte**& lowest_non_clean, | |
265 uintptr_t& lowest_non_clean_base_chunk_index, | |
266 size_t& lowest_non_clean_chunk_size) { | |
267 | |
268 int i = find_covering_region_containing(sp->bottom()); | |
269 MemRegion covered = _covered[i]; | |
270 size_t n_chunks = chunks_to_cover(covered); | |
271 | |
272 // Only the first thread to obtain the lock will resize the | |
273 // LNC array for the covered region. Any later expansion can't affect | |
274 // the used_at_save_marks region. | |
275 // (I observed a bug in which the first thread to execute this would | |
276 // resize, and then it would cause "expand_and_allocates" that would | |
277 // Increase the number of chunks in the covered region. Then a second | |
278 // thread would come and execute this, see that the size didn't match, | |
279 // and free and allocate again. So the first thread would be using a | |
280 // freed "_lowest_non_clean" array.) | |
281 | |
282 // Do a dirty read here. If we pass the conditional then take the rare | |
283 // event lock and do the read again in case some other thread had already | |
284 // succeeded and done the resize. | |
285 int cur_collection = Universe::heap()->total_collections(); | |
286 if (_last_LNC_resizing_collection[i] != cur_collection) { | |
287 MutexLocker x(ParGCRareEvent_lock); | |
288 if (_last_LNC_resizing_collection[i] != cur_collection) { | |
289 if (_lowest_non_clean[i] == NULL || | |
290 n_chunks != _lowest_non_clean_chunk_size[i]) { | |
291 | |
292 // Should we delete the old? | |
293 if (_lowest_non_clean[i] != NULL) { | |
294 assert(n_chunks != _lowest_non_clean_chunk_size[i], | |
295 "logical consequence"); | |
296 FREE_C_HEAP_ARRAY(CardPtr, _lowest_non_clean[i]); | |
297 _lowest_non_clean[i] = NULL; | |
298 } | |
299 // Now allocate a new one if necessary. | |
300 if (_lowest_non_clean[i] == NULL) { | |
301 _lowest_non_clean[i] = NEW_C_HEAP_ARRAY(CardPtr, n_chunks); | |
302 _lowest_non_clean_chunk_size[i] = n_chunks; | |
303 _lowest_non_clean_base_chunk_index[i] = addr_to_chunk_index(covered.start()); | |
304 for (int j = 0; j < (int)n_chunks; j++) | |
305 _lowest_non_clean[i][j] = NULL; | |
306 } | |
307 } | |
308 _last_LNC_resizing_collection[i] = cur_collection; | |
309 } | |
310 } | |
311 // In any case, now do the initialization. | |
312 lowest_non_clean = _lowest_non_clean[i]; | |
313 lowest_non_clean_base_chunk_index = _lowest_non_clean_base_chunk_index[i]; | |
314 lowest_non_clean_chunk_size = _lowest_non_clean_chunk_size[i]; | |
315 } |