Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp @ 2132:4947ee68d19c
7008136: CMS: assert((HeapWord*)nextChunk <= _limit) failed: sweep invariant
Summary: The recorded _sweep_limit may not necessarily remain a block boundary as the old generation expands during a concurrent cycle. Terminal actions inside the sweep closure need to be aware of this as they cross over the limit.
Reviewed-by: johnc, minqi
author | ysr |
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date | Thu, 06 Jan 2011 23:50:02 -0800 |
parents | f95d63e2154a |
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342 | 1 /* |
1972 | 2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
342 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP | |
27 | |
28 #include "gc_implementation/g1/sparsePRT.hpp" | |
29 | |
342 | 30 // Remembered set for a heap region. Represent a set of "cards" that |
31 // contain pointers into the owner heap region. Cards are defined somewhat | |
32 // abstractly, in terms of what the "BlockOffsetTable" in use can parse. | |
33 | |
34 class G1CollectedHeap; | |
35 class G1BlockOffsetSharedArray; | |
36 class HeapRegion; | |
37 class HeapRegionRemSetIterator; | |
38 class PosParPRT; | |
39 class SparsePRT; | |
40 | |
41 | |
42 // The "_coarse_map" is a bitmap with one bit for each region, where set | |
43 // bits indicate that the corresponding region may contain some pointer | |
44 // into the owning region. | |
45 | |
46 // The "_fine_grain_entries" array is an open hash table of PerRegionTables | |
47 // (PRTs), indicating regions for which we're keeping the RS as a set of | |
48 // cards. The strategy is to cap the size of the fine-grain table, | |
49 // deleting an entry and setting the corresponding coarse-grained bit when | |
50 // we would overflow this cap. | |
51 | |
52 // We use a mixture of locking and lock-free techniques here. We allow | |
53 // threads to locate PRTs without locking, but threads attempting to alter | |
54 // a bucket list obtain a lock. This means that any failing attempt to | |
55 // find a PRT must be retried with the lock. It might seem dangerous that | |
56 // a read can find a PRT that is concurrently deleted. This is all right, | |
57 // because: | |
58 // | |
59 // 1) We only actually free PRT's at safe points (though we reuse them at | |
60 // other times). | |
61 // 2) We find PRT's in an attempt to add entries. If a PRT is deleted, | |
62 // it's _coarse_map bit is set, so the that we were attempting to add | |
63 // is represented. If a deleted PRT is re-used, a thread adding a bit, | |
64 // thinking the PRT is for a different region, does no harm. | |
65 | |
549
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66 class OtherRegionsTable VALUE_OBJ_CLASS_SPEC { |
342 | 67 friend class HeapRegionRemSetIterator; |
68 | |
69 G1CollectedHeap* _g1h; | |
70 Mutex _m; | |
71 HeapRegion* _hr; | |
72 | |
73 // These are protected by "_m". | |
74 BitMap _coarse_map; | |
75 size_t _n_coarse_entries; | |
76 static jint _n_coarsenings; | |
77 | |
78 PosParPRT** _fine_grain_regions; | |
79 size_t _n_fine_entries; | |
80 | |
81 #define SAMPLE_FOR_EVICTION 1 | |
82 #if SAMPLE_FOR_EVICTION | |
83 size_t _fine_eviction_start; | |
84 static size_t _fine_eviction_stride; | |
85 static size_t _fine_eviction_sample_size; | |
86 #endif | |
87 | |
88 SparsePRT _sparse_table; | |
89 | |
90 // These are static after init. | |
91 static size_t _max_fine_entries; | |
92 static size_t _mod_max_fine_entries_mask; | |
93 | |
94 // Requires "prt" to be the first element of the bucket list appropriate | |
95 // for "hr". If this list contains an entry for "hr", return it, | |
96 // otherwise return "NULL". | |
97 PosParPRT* find_region_table(size_t ind, HeapRegion* hr) const; | |
98 | |
99 // Find, delete, and return a candidate PosParPRT, if any exists, | |
100 // adding the deleted region to the coarse bitmap. Requires the caller | |
101 // to hold _m, and the fine-grain table to be full. | |
102 PosParPRT* delete_region_table(); | |
103 | |
104 // If a PRT for "hr" is in the bucket list indicated by "ind" (which must | |
105 // be the correct index for "hr"), delete it and return true; else return | |
106 // false. | |
107 bool del_single_region_table(size_t ind, HeapRegion* hr); | |
108 | |
109 static jint _cache_probes; | |
110 static jint _cache_hits; | |
111 | |
112 // Indexed by thread X heap region, to minimize thread contention. | |
113 static int** _from_card_cache; | |
114 static size_t _from_card_cache_max_regions; | |
115 static size_t _from_card_cache_mem_size; | |
116 | |
117 public: | |
118 OtherRegionsTable(HeapRegion* hr); | |
119 | |
120 HeapRegion* hr() const { return _hr; } | |
121 | |
122 // For now. Could "expand" some tables in the future, so that this made | |
123 // sense. | |
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124 void add_reference(OopOrNarrowOopStar from, int tid); |
342 | 125 |
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126 void add_reference(OopOrNarrowOopStar from) { |
342 | 127 return add_reference(from, 0); |
128 } | |
129 | |
130 // Removes any entries shown by the given bitmaps to contain only dead | |
131 // objects. | |
132 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); | |
133 | |
134 // Not const because it takes a lock. | |
135 size_t occupied() const; | |
136 size_t occ_fine() const; | |
137 size_t occ_coarse() const; | |
138 size_t occ_sparse() const; | |
139 | |
140 static jint n_coarsenings() { return _n_coarsenings; } | |
141 | |
142 // Returns size in bytes. | |
143 // Not const because it takes a lock. | |
144 size_t mem_size() const; | |
145 static size_t static_mem_size(); | |
146 static size_t fl_mem_size(); | |
147 | |
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148 bool contains_reference(OopOrNarrowOopStar from) const; |
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149 bool contains_reference_locked(OopOrNarrowOopStar from) const; |
342 | 150 |
151 void clear(); | |
152 | |
153 // Specifically clear the from_card_cache. | |
154 void clear_fcc(); | |
155 | |
156 // "from_hr" is being cleared; remove any entries from it. | |
157 void clear_incoming_entry(HeapRegion* from_hr); | |
158 | |
159 // Declare the heap size (in # of regions) to the OtherRegionsTable. | |
160 // (Uses it to initialize from_card_cache). | |
161 static void init_from_card_cache(size_t max_regions); | |
162 | |
163 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use. | |
164 // Make sure any entries for higher regions are invalid. | |
165 static void shrink_from_card_cache(size_t new_n_regs); | |
166 | |
167 static void print_from_card_cache(); | |
168 | |
169 }; | |
170 | |
171 | |
172 class HeapRegionRemSet : public CHeapObj { | |
173 friend class VMStructs; | |
174 friend class HeapRegionRemSetIterator; | |
175 | |
176 public: | |
177 enum Event { | |
178 Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd | |
179 }; | |
180 | |
181 private: | |
182 G1BlockOffsetSharedArray* _bosa; | |
183 G1BlockOffsetSharedArray* bosa() const { return _bosa; } | |
184 | |
185 OtherRegionsTable _other_regions; | |
186 | |
187 enum ParIterState { Unclaimed, Claimed, Complete }; | |
1261 | 188 volatile ParIterState _iter_state; |
189 volatile jlong _iter_claimed; | |
342 | 190 |
191 // Unused unless G1RecordHRRSOops is true. | |
192 | |
193 static const int MaxRecorded = 1000000; | |
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194 static OopOrNarrowOopStar* _recorded_oops; |
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195 static HeapWord** _recorded_cards; |
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196 static HeapRegion** _recorded_regions; |
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197 static int _n_recorded; |
342 | 198 |
199 static const int MaxRecordedEvents = 1000; | |
200 static Event* _recorded_events; | |
201 static int* _recorded_event_index; | |
202 static int _n_recorded_events; | |
203 | |
204 static void print_event(outputStream* str, Event evnt); | |
205 | |
206 public: | |
207 HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, | |
208 HeapRegion* hr); | |
209 | |
210 static int num_par_rem_sets(); | |
1261 | 211 static void setup_remset_size(); |
342 | 212 |
213 HeapRegion* hr() const { | |
214 return _other_regions.hr(); | |
215 } | |
216 | |
217 size_t occupied() const { | |
218 return _other_regions.occupied(); | |
219 } | |
220 size_t occ_fine() const { | |
221 return _other_regions.occ_fine(); | |
222 } | |
223 size_t occ_coarse() const { | |
224 return _other_regions.occ_coarse(); | |
225 } | |
226 size_t occ_sparse() const { | |
227 return _other_regions.occ_sparse(); | |
228 } | |
229 | |
230 static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); } | |
231 | |
232 /* Used in the sequential case. Returns "true" iff this addition causes | |
233 the size limit to be reached. */ | |
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234 void add_reference(OopOrNarrowOopStar from) { |
342 | 235 _other_regions.add_reference(from); |
236 } | |
237 | |
238 /* Used in the parallel case. Returns "true" iff this addition causes | |
239 the size limit to be reached. */ | |
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240 void add_reference(OopOrNarrowOopStar from, int tid) { |
342 | 241 _other_regions.add_reference(from, tid); |
242 } | |
243 | |
244 // Removes any entries shown by the given bitmaps to contain only dead | |
245 // objects. | |
246 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); | |
247 | |
248 // The region is being reclaimed; clear its remset, and any mention of | |
249 // entries for this region in other remsets. | |
250 void clear(); | |
251 | |
252 // Forget any entries due to pointers from "from_hr". | |
253 void clear_incoming_entry(HeapRegion* from_hr) { | |
254 _other_regions.clear_incoming_entry(from_hr); | |
255 } | |
256 | |
257 #if 0 | |
258 virtual void cleanup() = 0; | |
259 #endif | |
260 | |
261 // Should be called from single-threaded code. | |
262 void init_for_par_iteration(); | |
263 // Attempt to claim the region. Returns true iff this call caused an | |
264 // atomic transition from Unclaimed to Claimed. | |
265 bool claim_iter(); | |
266 // Sets the iteration state to "complete". | |
267 void set_iter_complete(); | |
268 // Returns "true" iff the region's iteration is complete. | |
269 bool iter_is_complete(); | |
270 | |
1261 | 271 // Support for claiming blocks of cards during iteration |
272 void set_iter_claimed(size_t x) { _iter_claimed = (jlong)x; } | |
273 size_t iter_claimed() const { return (size_t)_iter_claimed; } | |
274 // Claim the next block of cards | |
275 size_t iter_claimed_next(size_t step) { | |
276 size_t current, next; | |
277 do { | |
278 current = iter_claimed(); | |
279 next = current + step; | |
280 } while (Atomic::cmpxchg((jlong)next, &_iter_claimed, (jlong)current) != (jlong)current); | |
281 return current; | |
282 } | |
283 | |
342 | 284 // Initialize the given iterator to iterate over this rem set. |
285 void init_iterator(HeapRegionRemSetIterator* iter) const; | |
286 | |
287 #if 0 | |
288 // Apply the "do_card" method to the start address of every card in the | |
289 // rem set. Returns false if some application of the closure aborted. | |
290 virtual bool card_iterate(CardClosure* iter) = 0; | |
291 #endif | |
292 | |
293 // The actual # of bytes this hr_remset takes up. | |
294 size_t mem_size() { | |
295 return _other_regions.mem_size() | |
296 // This correction is necessary because the above includes the second | |
297 // part. | |
298 + sizeof(this) - sizeof(OtherRegionsTable); | |
299 } | |
300 | |
301 // Returns the memory occupancy of all static data structures associated | |
302 // with remembered sets. | |
303 static size_t static_mem_size() { | |
304 return OtherRegionsTable::static_mem_size(); | |
305 } | |
306 | |
307 // Returns the memory occupancy of all free_list data structures associated | |
308 // with remembered sets. | |
309 static size_t fl_mem_size() { | |
310 return OtherRegionsTable::fl_mem_size(); | |
311 } | |
312 | |
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313 bool contains_reference(OopOrNarrowOopStar from) const { |
342 | 314 return _other_regions.contains_reference(from); |
315 } | |
316 void print() const; | |
317 | |
318 // Called during a stop-world phase to perform any deferred cleanups. | |
319 // The second version may be called by parallel threads after then finish | |
320 // collection work. | |
321 static void cleanup(); | |
322 static void par_cleanup(); | |
323 | |
324 // Declare the heap size (in # of regions) to the HeapRegionRemSet(s). | |
325 // (Uses it to initialize from_card_cache). | |
326 static void init_heap(size_t max_regions) { | |
327 OtherRegionsTable::init_from_card_cache(max_regions); | |
328 } | |
329 | |
330 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use. | |
331 static void shrink_heap(size_t new_n_regs) { | |
332 OtherRegionsTable::shrink_from_card_cache(new_n_regs); | |
333 } | |
334 | |
335 #ifndef PRODUCT | |
336 static void print_from_card_cache() { | |
337 OtherRegionsTable::print_from_card_cache(); | |
338 } | |
339 #endif | |
340 | |
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341 static void record(HeapRegion* hr, OopOrNarrowOopStar f); |
342 | 342 static void print_recorded(); |
343 static void record_event(Event evnt); | |
344 | |
345 // Run unit tests. | |
346 #ifndef PRODUCT | |
347 static void test(); | |
348 #endif | |
349 | |
350 }; | |
351 | |
352 class HeapRegionRemSetIterator : public CHeapObj { | |
353 | |
354 // The region over which we're iterating. | |
355 const HeapRegionRemSet* _hrrs; | |
356 | |
357 // Local caching of HRRS fields. | |
358 const BitMap* _coarse_map; | |
359 PosParPRT** _fine_grain_regions; | |
360 | |
361 G1BlockOffsetSharedArray* _bosa; | |
362 G1CollectedHeap* _g1h; | |
363 | |
364 // The number yielded since initialization. | |
365 size_t _n_yielded_fine; | |
366 size_t _n_yielded_coarse; | |
367 size_t _n_yielded_sparse; | |
368 | |
369 // If true we're iterating over the coarse table; if false the fine | |
370 // table. | |
371 enum IterState { | |
372 Sparse, | |
373 Fine, | |
374 Coarse | |
375 }; | |
376 IterState _is; | |
377 | |
378 // In both kinds of iteration, heap offset of first card of current | |
379 // region. | |
380 size_t _cur_region_card_offset; | |
381 // Card offset within cur region. | |
382 size_t _cur_region_cur_card; | |
383 | |
384 // Coarse table iteration fields: | |
385 | |
386 // Current region index; | |
387 int _coarse_cur_region_index; | |
388 int _coarse_cur_region_cur_card; | |
389 | |
390 bool coarse_has_next(size_t& card_index); | |
391 | |
392 // Fine table iteration fields: | |
393 | |
394 // Index of bucket-list we're working on. | |
395 int _fine_array_index; | |
396 // Per Region Table we're doing within current bucket list. | |
397 PosParPRT* _fine_cur_prt; | |
398 | |
399 /* SparsePRT::*/ SparsePRTIter _sparse_iter; | |
400 | |
401 void fine_find_next_non_null_prt(); | |
402 | |
403 bool fine_has_next(); | |
404 bool fine_has_next(size_t& card_index); | |
405 | |
406 public: | |
407 // We require an iterator to be initialized before use, so the | |
408 // constructor does little. | |
409 HeapRegionRemSetIterator(); | |
410 | |
411 void initialize(const HeapRegionRemSet* hrrs); | |
412 | |
413 // If there remains one or more cards to be yielded, returns true and | |
414 // sets "card_index" to one of those cards (which is then considered | |
415 // yielded.) Otherwise, returns false (and leaves "card_index" | |
416 // undefined.) | |
417 bool has_next(size_t& card_index); | |
418 | |
419 size_t n_yielded_fine() { return _n_yielded_fine; } | |
420 size_t n_yielded_coarse() { return _n_yielded_coarse; } | |
421 size_t n_yielded_sparse() { return _n_yielded_sparse; } | |
422 size_t n_yielded() { | |
423 return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse(); | |
424 } | |
425 }; | |
426 | |
427 #if 0 | |
428 class CardClosure: public Closure { | |
429 public: | |
430 virtual void do_card(HeapWord* card_start) = 0; | |
431 }; | |
432 | |
433 #endif | |
1972 | 434 |
435 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP |