Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp @ 549:fe3d7c11b4b7
6700941: G1: allocation spec missing for some G1 classes
Reviewed-by: tonyp
| author | apetrusenko |
|---|---|
| date | Tue, 10 Feb 2009 18:39:09 +0300 |
| parents | 37f87013dfd8 |
| children | 0fbdb4381b99 |
| rev | line source |
|---|---|
| 342 | 1 /* |
| 2 * Copyright 2001-2007 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 // Remembered set for a heap region. Represent a set of "cards" that | |
| 26 // contain pointers into the owner heap region. Cards are defined somewhat | |
| 27 // abstractly, in terms of what the "BlockOffsetTable" in use can parse. | |
| 28 | |
| 29 class G1CollectedHeap; | |
| 30 class G1BlockOffsetSharedArray; | |
| 31 class HeapRegion; | |
| 32 class HeapRegionRemSetIterator; | |
| 33 class PosParPRT; | |
| 34 class SparsePRT; | |
| 35 | |
| 36 | |
| 37 // The "_coarse_map" is a bitmap with one bit for each region, where set | |
| 38 // bits indicate that the corresponding region may contain some pointer | |
| 39 // into the owning region. | |
| 40 | |
| 41 // The "_fine_grain_entries" array is an open hash table of PerRegionTables | |
| 42 // (PRTs), indicating regions for which we're keeping the RS as a set of | |
| 43 // cards. The strategy is to cap the size of the fine-grain table, | |
| 44 // deleting an entry and setting the corresponding coarse-grained bit when | |
| 45 // we would overflow this cap. | |
| 46 | |
| 47 // We use a mixture of locking and lock-free techniques here. We allow | |
| 48 // threads to locate PRTs without locking, but threads attempting to alter | |
| 49 // a bucket list obtain a lock. This means that any failing attempt to | |
| 50 // find a PRT must be retried with the lock. It might seem dangerous that | |
| 51 // a read can find a PRT that is concurrently deleted. This is all right, | |
| 52 // because: | |
| 53 // | |
| 54 // 1) We only actually free PRT's at safe points (though we reuse them at | |
| 55 // other times). | |
| 56 // 2) We find PRT's in an attempt to add entries. If a PRT is deleted, | |
| 57 // it's _coarse_map bit is set, so the that we were attempting to add | |
| 58 // is represented. If a deleted PRT is re-used, a thread adding a bit, | |
| 59 // thinking the PRT is for a different region, does no harm. | |
| 60 | |
|
549
fe3d7c11b4b7
6700941: G1: allocation spec missing for some G1 classes
apetrusenko
parents:
342
diff
changeset
|
61 class OtherRegionsTable VALUE_OBJ_CLASS_SPEC { |
| 342 | 62 friend class HeapRegionRemSetIterator; |
| 63 | |
| 64 G1CollectedHeap* _g1h; | |
| 65 Mutex _m; | |
| 66 HeapRegion* _hr; | |
| 67 | |
| 68 // These are protected by "_m". | |
| 69 BitMap _coarse_map; | |
| 70 size_t _n_coarse_entries; | |
| 71 static jint _n_coarsenings; | |
| 72 | |
| 73 PosParPRT** _fine_grain_regions; | |
| 74 size_t _n_fine_entries; | |
| 75 | |
| 76 #define SAMPLE_FOR_EVICTION 1 | |
| 77 #if SAMPLE_FOR_EVICTION | |
| 78 size_t _fine_eviction_start; | |
| 79 static size_t _fine_eviction_stride; | |
| 80 static size_t _fine_eviction_sample_size; | |
| 81 #endif | |
| 82 | |
| 83 SparsePRT _sparse_table; | |
| 84 | |
| 85 // These are static after init. | |
| 86 static size_t _max_fine_entries; | |
| 87 static size_t _mod_max_fine_entries_mask; | |
| 88 | |
| 89 // Requires "prt" to be the first element of the bucket list appropriate | |
| 90 // for "hr". If this list contains an entry for "hr", return it, | |
| 91 // otherwise return "NULL". | |
| 92 PosParPRT* find_region_table(size_t ind, HeapRegion* hr) const; | |
| 93 | |
| 94 // Find, delete, and return a candidate PosParPRT, if any exists, | |
| 95 // adding the deleted region to the coarse bitmap. Requires the caller | |
| 96 // to hold _m, and the fine-grain table to be full. | |
| 97 PosParPRT* delete_region_table(); | |
| 98 | |
| 99 // If a PRT for "hr" is in the bucket list indicated by "ind" (which must | |
| 100 // be the correct index for "hr"), delete it and return true; else return | |
| 101 // false. | |
| 102 bool del_single_region_table(size_t ind, HeapRegion* hr); | |
| 103 | |
| 104 static jint _cache_probes; | |
| 105 static jint _cache_hits; | |
| 106 | |
| 107 // Indexed by thread X heap region, to minimize thread contention. | |
| 108 static int** _from_card_cache; | |
| 109 static size_t _from_card_cache_max_regions; | |
| 110 static size_t _from_card_cache_mem_size; | |
| 111 | |
| 112 public: | |
| 113 OtherRegionsTable(HeapRegion* hr); | |
| 114 | |
| 115 HeapRegion* hr() const { return _hr; } | |
| 116 | |
| 117 // For now. Could "expand" some tables in the future, so that this made | |
| 118 // sense. | |
| 119 void add_reference(oop* from, int tid); | |
| 120 | |
| 121 void add_reference(oop* from) { | |
| 122 return add_reference(from, 0); | |
| 123 } | |
| 124 | |
| 125 // Removes any entries shown by the given bitmaps to contain only dead | |
| 126 // objects. | |
| 127 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); | |
| 128 | |
| 129 // Not const because it takes a lock. | |
| 130 size_t occupied() const; | |
| 131 size_t occ_fine() const; | |
| 132 size_t occ_coarse() const; | |
| 133 size_t occ_sparse() const; | |
| 134 | |
| 135 static jint n_coarsenings() { return _n_coarsenings; } | |
| 136 | |
| 137 // Returns size in bytes. | |
| 138 // Not const because it takes a lock. | |
| 139 size_t mem_size() const; | |
| 140 static size_t static_mem_size(); | |
| 141 static size_t fl_mem_size(); | |
| 142 | |
| 143 bool contains_reference(oop* from) const; | |
| 144 bool contains_reference_locked(oop* from) const; | |
| 145 | |
| 146 void clear(); | |
| 147 | |
| 148 // Specifically clear the from_card_cache. | |
| 149 void clear_fcc(); | |
| 150 | |
| 151 // "from_hr" is being cleared; remove any entries from it. | |
| 152 void clear_incoming_entry(HeapRegion* from_hr); | |
| 153 | |
| 154 // Declare the heap size (in # of regions) to the OtherRegionsTable. | |
| 155 // (Uses it to initialize from_card_cache). | |
| 156 static void init_from_card_cache(size_t max_regions); | |
| 157 | |
| 158 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use. | |
| 159 // Make sure any entries for higher regions are invalid. | |
| 160 static void shrink_from_card_cache(size_t new_n_regs); | |
| 161 | |
| 162 static void print_from_card_cache(); | |
| 163 | |
| 164 }; | |
| 165 | |
| 166 | |
| 167 class HeapRegionRemSet : public CHeapObj { | |
| 168 friend class VMStructs; | |
| 169 friend class HeapRegionRemSetIterator; | |
| 170 | |
| 171 public: | |
| 172 enum Event { | |
| 173 Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd | |
| 174 }; | |
| 175 | |
| 176 private: | |
| 177 G1BlockOffsetSharedArray* _bosa; | |
| 178 G1BlockOffsetSharedArray* bosa() const { return _bosa; } | |
| 179 | |
| 180 static bool _par_traversal; | |
| 181 | |
| 182 OtherRegionsTable _other_regions; | |
| 183 | |
| 184 // One set bit for every region that has an entry for this one. | |
| 185 BitMap _outgoing_region_map; | |
| 186 | |
| 187 // Clear entries for the current region in any rem sets named in | |
| 188 // the _outgoing_region_map. | |
| 189 void clear_outgoing_entries(); | |
| 190 | |
| 191 #if MAYBE | |
| 192 // Audit the given card index. | |
| 193 void audit_card(size_t card_num, HeapRegion* hr, u2* rc_arr, | |
| 194 HeapRegionRemSet* empty_cards, size_t* one_obj_cards); | |
| 195 | |
| 196 // Assumes that "audit_stage1" has been called for "hr", to set up | |
| 197 // "shadow" and "new_rs" appropriately. Identifies individual popular | |
| 198 // objects; returns "true" if any are found. | |
| 199 bool audit_find_pop(HeapRegion* hr, u2* rc_arr); | |
| 200 | |
| 201 // Assumes that "audit_stage1" has been called for "hr", to set up | |
| 202 // "shadow" and "new_rs" appropriately. Identifies individual popular | |
| 203 // objects, and determines the number of entries in "new_rs" if any such | |
| 204 // popular objects are ignored. If this is sufficiently small, returns | |
| 205 // "false" to indicate that a constraint should not be introduced. | |
| 206 // Otherwise, returns "true" to indicate that we should go ahead with | |
| 207 // adding the constraint. | |
| 208 bool audit_stag(HeapRegion* hr, u2* rc_arr); | |
| 209 | |
| 210 | |
| 211 u2* alloc_rc_array(); | |
| 212 | |
| 213 SeqHeapRegionRemSet* audit_post(u2* rc_arr, size_t multi_obj_crds, | |
| 214 SeqHeapRegionRemSet* empty_cards); | |
| 215 #endif | |
| 216 | |
| 217 enum ParIterState { Unclaimed, Claimed, Complete }; | |
| 218 ParIterState _iter_state; | |
| 219 | |
| 220 // Unused unless G1RecordHRRSOops is true. | |
| 221 | |
| 222 static const int MaxRecorded = 1000000; | |
| 223 static oop** _recorded_oops; | |
| 224 static HeapWord** _recorded_cards; | |
| 225 static HeapRegion** _recorded_regions; | |
| 226 static int _n_recorded; | |
| 227 | |
| 228 static const int MaxRecordedEvents = 1000; | |
| 229 static Event* _recorded_events; | |
| 230 static int* _recorded_event_index; | |
| 231 static int _n_recorded_events; | |
| 232 | |
| 233 static void print_event(outputStream* str, Event evnt); | |
| 234 | |
| 235 public: | |
| 236 HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, | |
| 237 HeapRegion* hr); | |
| 238 | |
| 239 static int num_par_rem_sets(); | |
| 240 static bool par_traversal() { return _par_traversal; } | |
| 241 static void set_par_traversal(bool b); | |
| 242 | |
| 243 HeapRegion* hr() const { | |
| 244 return _other_regions.hr(); | |
| 245 } | |
| 246 | |
| 247 size_t occupied() const { | |
| 248 return _other_regions.occupied(); | |
| 249 } | |
| 250 size_t occ_fine() const { | |
| 251 return _other_regions.occ_fine(); | |
| 252 } | |
| 253 size_t occ_coarse() const { | |
| 254 return _other_regions.occ_coarse(); | |
| 255 } | |
| 256 size_t occ_sparse() const { | |
| 257 return _other_regions.occ_sparse(); | |
| 258 } | |
| 259 | |
| 260 static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); } | |
| 261 | |
| 262 /* Used in the sequential case. Returns "true" iff this addition causes | |
| 263 the size limit to be reached. */ | |
| 264 bool add_reference(oop* from) { | |
| 265 _other_regions.add_reference(from); | |
| 266 return false; | |
| 267 } | |
| 268 | |
| 269 /* Used in the parallel case. Returns "true" iff this addition causes | |
| 270 the size limit to be reached. */ | |
| 271 bool add_reference(oop* from, int tid) { | |
| 272 _other_regions.add_reference(from, tid); | |
| 273 return false; | |
| 274 } | |
| 275 | |
| 276 // Records the fact that the current region contains an outgoing | |
| 277 // reference into "to_hr". | |
| 278 void add_outgoing_reference(HeapRegion* to_hr); | |
| 279 | |
| 280 // Removes any entries shown by the given bitmaps to contain only dead | |
| 281 // objects. | |
| 282 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm); | |
| 283 | |
| 284 // The region is being reclaimed; clear its remset, and any mention of | |
| 285 // entries for this region in other remsets. | |
| 286 void clear(); | |
| 287 | |
| 288 // Forget any entries due to pointers from "from_hr". | |
| 289 void clear_incoming_entry(HeapRegion* from_hr) { | |
| 290 _other_regions.clear_incoming_entry(from_hr); | |
| 291 } | |
| 292 | |
| 293 #if 0 | |
| 294 virtual void cleanup() = 0; | |
| 295 #endif | |
| 296 | |
| 297 // Should be called from single-threaded code. | |
| 298 void init_for_par_iteration(); | |
| 299 // Attempt to claim the region. Returns true iff this call caused an | |
| 300 // atomic transition from Unclaimed to Claimed. | |
| 301 bool claim_iter(); | |
| 302 // Sets the iteration state to "complete". | |
| 303 void set_iter_complete(); | |
| 304 // Returns "true" iff the region's iteration is complete. | |
| 305 bool iter_is_complete(); | |
| 306 | |
| 307 // Initialize the given iterator to iterate over this rem set. | |
| 308 void init_iterator(HeapRegionRemSetIterator* iter) const; | |
| 309 | |
| 310 #if 0 | |
| 311 // Apply the "do_card" method to the start address of every card in the | |
| 312 // rem set. Returns false if some application of the closure aborted. | |
| 313 virtual bool card_iterate(CardClosure* iter) = 0; | |
| 314 #endif | |
| 315 | |
| 316 // The actual # of bytes this hr_remset takes up. | |
| 317 size_t mem_size() { | |
| 318 return _other_regions.mem_size() | |
| 319 // This correction is necessary because the above includes the second | |
| 320 // part. | |
| 321 + sizeof(this) - sizeof(OtherRegionsTable); | |
| 322 } | |
| 323 | |
| 324 // Returns the memory occupancy of all static data structures associated | |
| 325 // with remembered sets. | |
| 326 static size_t static_mem_size() { | |
| 327 return OtherRegionsTable::static_mem_size(); | |
| 328 } | |
| 329 | |
| 330 // Returns the memory occupancy of all free_list data structures associated | |
| 331 // with remembered sets. | |
| 332 static size_t fl_mem_size() { | |
| 333 return OtherRegionsTable::fl_mem_size(); | |
| 334 } | |
| 335 | |
| 336 bool contains_reference(oop* from) const { | |
| 337 return _other_regions.contains_reference(from); | |
| 338 } | |
| 339 void print() const; | |
| 340 | |
| 341 #if MAYBE | |
| 342 // We are about to introduce a constraint, requiring the collection time | |
| 343 // of the region owning this RS to be <= "hr", and forgetting pointers | |
| 344 // from the owning region to "hr." Before doing so, examines this rem | |
| 345 // set for pointers to "hr", possibly identifying some popular objects., | |
| 346 // and possibly finding some cards to no longer contain pointers to "hr", | |
| 347 // | |
| 348 // These steps may prevent the the constraint from being necessary; in | |
| 349 // which case returns a set of cards now thought to contain no pointers | |
| 350 // into HR. In the normal (I assume) case, returns NULL, indicating that | |
| 351 // we should go ahead and add the constraint. | |
| 352 virtual SeqHeapRegionRemSet* audit(HeapRegion* hr) = 0; | |
| 353 #endif | |
| 354 | |
| 355 // Called during a stop-world phase to perform any deferred cleanups. | |
| 356 // The second version may be called by parallel threads after then finish | |
| 357 // collection work. | |
| 358 static void cleanup(); | |
| 359 static void par_cleanup(); | |
| 360 | |
| 361 // Declare the heap size (in # of regions) to the HeapRegionRemSet(s). | |
| 362 // (Uses it to initialize from_card_cache). | |
| 363 static void init_heap(size_t max_regions) { | |
| 364 OtherRegionsTable::init_from_card_cache(max_regions); | |
| 365 } | |
| 366 | |
| 367 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use. | |
| 368 static void shrink_heap(size_t new_n_regs) { | |
| 369 OtherRegionsTable::shrink_from_card_cache(new_n_regs); | |
| 370 } | |
| 371 | |
| 372 #ifndef PRODUCT | |
| 373 static void print_from_card_cache() { | |
| 374 OtherRegionsTable::print_from_card_cache(); | |
| 375 } | |
| 376 #endif | |
| 377 | |
| 378 static void record(HeapRegion* hr, oop* f); | |
| 379 static void print_recorded(); | |
| 380 static void record_event(Event evnt); | |
| 381 | |
| 382 // Run unit tests. | |
| 383 #ifndef PRODUCT | |
| 384 static void test(); | |
| 385 #endif | |
| 386 | |
| 387 }; | |
| 388 | |
| 389 class HeapRegionRemSetIterator : public CHeapObj { | |
| 390 | |
| 391 // The region over which we're iterating. | |
| 392 const HeapRegionRemSet* _hrrs; | |
| 393 | |
| 394 // Local caching of HRRS fields. | |
| 395 const BitMap* _coarse_map; | |
| 396 PosParPRT** _fine_grain_regions; | |
| 397 | |
| 398 G1BlockOffsetSharedArray* _bosa; | |
| 399 G1CollectedHeap* _g1h; | |
| 400 | |
| 401 // The number yielded since initialization. | |
| 402 size_t _n_yielded_fine; | |
| 403 size_t _n_yielded_coarse; | |
| 404 size_t _n_yielded_sparse; | |
| 405 | |
| 406 // If true we're iterating over the coarse table; if false the fine | |
| 407 // table. | |
| 408 enum IterState { | |
| 409 Sparse, | |
| 410 Fine, | |
| 411 Coarse | |
| 412 }; | |
| 413 IterState _is; | |
| 414 | |
| 415 // In both kinds of iteration, heap offset of first card of current | |
| 416 // region. | |
| 417 size_t _cur_region_card_offset; | |
| 418 // Card offset within cur region. | |
| 419 size_t _cur_region_cur_card; | |
| 420 | |
| 421 // Coarse table iteration fields: | |
| 422 | |
| 423 // Current region index; | |
| 424 int _coarse_cur_region_index; | |
| 425 int _coarse_cur_region_cur_card; | |
| 426 | |
| 427 bool coarse_has_next(size_t& card_index); | |
| 428 | |
| 429 // Fine table iteration fields: | |
| 430 | |
| 431 // Index of bucket-list we're working on. | |
| 432 int _fine_array_index; | |
| 433 // Per Region Table we're doing within current bucket list. | |
| 434 PosParPRT* _fine_cur_prt; | |
| 435 | |
| 436 /* SparsePRT::*/ SparsePRTIter _sparse_iter; | |
| 437 | |
| 438 void fine_find_next_non_null_prt(); | |
| 439 | |
| 440 bool fine_has_next(); | |
| 441 bool fine_has_next(size_t& card_index); | |
| 442 | |
| 443 public: | |
| 444 // We require an iterator to be initialized before use, so the | |
| 445 // constructor does little. | |
| 446 HeapRegionRemSetIterator(); | |
| 447 | |
| 448 void initialize(const HeapRegionRemSet* hrrs); | |
| 449 | |
| 450 // If there remains one or more cards to be yielded, returns true and | |
| 451 // sets "card_index" to one of those cards (which is then considered | |
| 452 // yielded.) Otherwise, returns false (and leaves "card_index" | |
| 453 // undefined.) | |
| 454 bool has_next(size_t& card_index); | |
| 455 | |
| 456 size_t n_yielded_fine() { return _n_yielded_fine; } | |
| 457 size_t n_yielded_coarse() { return _n_yielded_coarse; } | |
| 458 size_t n_yielded_sparse() { return _n_yielded_sparse; } | |
| 459 size_t n_yielded() { | |
| 460 return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse(); | |
| 461 } | |
| 462 }; | |
| 463 | |
| 464 #if 0 | |
| 465 class CardClosure: public Closure { | |
| 466 public: | |
| 467 virtual void do_card(HeapWord* card_start) = 0; | |
| 468 }; | |
| 469 | |
| 470 #endif |