Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp @ 2149:7e37af9d69ef
7011379: G1: overly long concurrent marking cycles
Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads.
Reviewed-by: johnc, ysr
| author | tonyp |
|---|---|
| date | Wed, 19 Jan 2011 09:35:17 -0500 |
| parents | f95d63e2154a |
| children | 97ba643ea3ed |
| rev | line source |
|---|---|
| 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 | |
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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 |