1 /* 2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc/g1/concurrentG1Refine.hpp" 27 #include "gc/g1/concurrentG1RefineThread.hpp" 28 #include "gc/g1/g1BlockOffsetTable.inline.hpp" 29 #include "gc/g1/g1CollectedHeap.inline.hpp" 30 #include "gc/g1/g1CollectorPolicy.hpp" 31 #include "gc/g1/g1GCPhaseTimes.hpp" 32 #include "gc/g1/g1HotCardCache.hpp" 33 #include "gc/g1/g1OopClosures.inline.hpp" 34 #include "gc/g1/g1RemSet.inline.hpp" 35 #include "gc/g1/heapRegion.inline.hpp" 36 #include "gc/g1/heapRegionManager.inline.hpp" 37 #include "gc/g1/heapRegionRemSet.hpp" 38 #include "memory/iterator.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "utilities/globalDefinitions.hpp" 41 #include "utilities/intHisto.hpp" 42 #include "utilities/stack.inline.hpp" 43 44 G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs) : 45 _g1(g1), 46 _conc_refine_cards(0), 47 _ct_bs(ct_bs), 48 _g1p(_g1->g1_policy()), 49 _cg1r(g1->concurrent_g1_refine()), 50 _cset_rs_update_cl(NULL), 51 _prev_period_summary(), 52 _into_cset_dirty_card_queue_set(false) 53 { 54 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, n_workers(), mtGC); 55 for (uint i = 0; i < n_workers(); i++) { 56 _cset_rs_update_cl[i] = NULL; 57 } 58 if (log_is_enabled(Trace, gc, remset)) { 59 _prev_period_summary.initialize(this); 60 } 61 // Initialize the card queue set used to hold cards containing 62 // references into the collection set. 63 _into_cset_dirty_card_queue_set.initialize(NULL, // Should never be called by the Java code 64 DirtyCardQ_CBL_mon, 65 DirtyCardQ_FL_lock, 66 -1, // never trigger processing 67 -1, // no limit on length 68 Shared_DirtyCardQ_lock, 69 &JavaThread::dirty_card_queue_set()); 70 } 71 72 G1RemSet::~G1RemSet() { 73 for (uint i = 0; i < n_workers(); i++) { 74 assert(_cset_rs_update_cl[i] == NULL, "it should be"); 75 } 76 FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl); 77 } 78 79 ScanRSClosure::ScanRSClosure(G1ParPushHeapRSClosure* oc, 80 CodeBlobClosure* code_root_cl, 81 uint worker_i) : 82 _oc(oc), 83 _code_root_cl(code_root_cl), 84 _strong_code_root_scan_time_sec(0.0), 85 _cards(0), 86 _cards_done(0), 87 _worker_i(worker_i), 88 _try_claimed(false) { 89 _g1h = G1CollectedHeap::heap(); 90 _bot_shared = _g1h->bot_shared(); 91 _ct_bs = _g1h->g1_barrier_set(); 92 _block_size = MAX2<size_t>(G1RSetScanBlockSize, 1); 93 } 94 95 void ScanRSClosure::scanCard(size_t index, HeapRegion *r) { 96 // Stack allocate the DirtyCardToOopClosure instance 97 HeapRegionDCTOC cl(_g1h, r, _oc, 98 CardTableModRefBS::Precise); 99 100 // Set the "from" region in the closure. 101 _oc->set_region(r); 102 MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words); 103 MemRegion pre_gc_allocated(r->bottom(), r->scan_top()); 104 MemRegion mr = pre_gc_allocated.intersection(card_region); 105 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) { 106 // We make the card as "claimed" lazily (so races are possible 107 // but they're benign), which reduces the number of duplicate 108 // scans (the rsets of the regions in the cset can intersect). 109 _ct_bs->set_card_claimed(index); 110 _cards_done++; 111 cl.do_MemRegion(mr); 112 } 113 } 114 115 void ScanRSClosure::scan_strong_code_roots(HeapRegion* r) { 116 double scan_start = os::elapsedTime(); 117 r->strong_code_roots_do(_code_root_cl); 118 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start); 119 } 120 121 bool ScanRSClosure::doHeapRegion(HeapRegion* r) { 122 assert(r->in_collection_set(), "should only be called on elements of CS."); 123 HeapRegionRemSet* hrrs = r->rem_set(); 124 if (hrrs->iter_is_complete()) return false; // All done. 125 if (!_try_claimed && !hrrs->claim_iter()) return false; 126 // If we ever free the collection set concurrently, we should also 127 // clear the card table concurrently therefore we won't need to 128 // add regions of the collection set to the dirty cards region. 129 _g1h->push_dirty_cards_region(r); 130 // If we didn't return above, then 131 // _try_claimed || r->claim_iter() 132 // is true: either we're supposed to work on claimed-but-not-complete 133 // regions, or we successfully claimed the region. 134 135 HeapRegionRemSetIterator iter(hrrs); 136 size_t card_index; 137 138 // We claim cards in block so as to reduce the contention. The block size is determined by 139 // the G1RSetScanBlockSize parameter. 140 size_t jump_to_card = hrrs->iter_claimed_next(_block_size); 141 for (size_t current_card = 0; iter.has_next(card_index); current_card++) { 142 if (current_card >= jump_to_card + _block_size) { 143 jump_to_card = hrrs->iter_claimed_next(_block_size); 144 } 145 if (current_card < jump_to_card) continue; 146 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index); 147 148 HeapRegion* card_region = _g1h->heap_region_containing(card_start); 149 _cards++; 150 151 if (!card_region->is_on_dirty_cards_region_list()) { 152 _g1h->push_dirty_cards_region(card_region); 153 } 154 155 // If the card is dirty, then we will scan it during updateRS. 156 if (!card_region->in_collection_set() && 157 !_ct_bs->is_card_dirty(card_index)) { 158 scanCard(card_index, card_region); 159 } 160 } 161 if (!_try_claimed) { 162 // Scan the strong code root list attached to the current region 163 scan_strong_code_roots(r); 164 165 hrrs->set_iter_complete(); 166 } 167 return false; 168 } 169 170 size_t G1RemSet::scanRS(G1ParPushHeapRSClosure* oc, 171 CodeBlobClosure* heap_region_codeblobs, 172 uint worker_i) { 173 double rs_time_start = os::elapsedTime(); 174 175 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i); 176 177 ScanRSClosure scanRScl(oc, heap_region_codeblobs, worker_i); 178 179 _g1->collection_set_iterate_from(startRegion, &scanRScl); 180 scanRScl.set_try_claimed(); 181 _g1->collection_set_iterate_from(startRegion, &scanRScl); 182 183 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) 184 - scanRScl.strong_code_root_scan_time_sec(); 185 186 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::ScanRS, worker_i, scan_rs_time_sec); 187 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::CodeRoots, worker_i, scanRScl.strong_code_root_scan_time_sec()); 188 189 return scanRScl.cards_done(); 190 } 191 192 // Closure used for updating RSets and recording references that 193 // point into the collection set. Only called during an 194 // evacuation pause. 195 196 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure { 197 G1RemSet* _g1rs; 198 DirtyCardQueue* _into_cset_dcq; 199 public: 200 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h, 201 DirtyCardQueue* into_cset_dcq) : 202 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq) 203 {} 204 205 bool do_card_ptr(jbyte* card_ptr, uint worker_i) { 206 // The only time we care about recording cards that 207 // contain references that point into the collection set 208 // is during RSet updating within an evacuation pause. 209 // In this case worker_i should be the id of a GC worker thread. 210 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause"); 211 assert(worker_i < ParallelGCThreads, "should be a GC worker"); 212 213 if (_g1rs->refine_card(card_ptr, worker_i, true)) { 214 // 'card_ptr' contains references that point into the collection 215 // set. We need to record the card in the DCQS 216 // (_into_cset_dirty_card_queue_set) 217 // that's used for that purpose. 218 // 219 // Enqueue the card 220 _into_cset_dcq->enqueue(card_ptr); 221 } 222 return true; 223 } 224 }; 225 226 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) { 227 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq); 228 229 G1GCParPhaseTimesTracker x(_g1p->phase_times(), G1GCPhaseTimes::UpdateRS, worker_i); 230 { 231 // Apply the closure to the entries of the hot card cache. 232 G1GCParPhaseTimesTracker y(_g1p->phase_times(), G1GCPhaseTimes::ScanHCC, worker_i); 233 _g1->iterate_hcc_closure(&into_cset_update_rs_cl, worker_i); 234 } 235 // Apply the closure to all remaining log entries. 236 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, worker_i); 237 } 238 239 void G1RemSet::cleanupHRRS() { 240 HeapRegionRemSet::cleanup(); 241 } 242 243 size_t G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc, 244 CodeBlobClosure* heap_region_codeblobs, 245 uint worker_i) { 246 // We cache the value of 'oc' closure into the appropriate slot in the 247 // _cset_rs_update_cl for this worker 248 assert(worker_i < n_workers(), "sanity"); 249 _cset_rs_update_cl[worker_i] = oc; 250 251 // A DirtyCardQueue that is used to hold cards containing references 252 // that point into the collection set. This DCQ is associated with a 253 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal 254 // circumstances (i.e. the pause successfully completes), these cards 255 // are just discarded (there's no need to update the RSets of regions 256 // that were in the collection set - after the pause these regions 257 // are wholly 'free' of live objects. In the event of an evacuation 258 // failure the cards/buffers in this queue set are passed to the 259 // DirtyCardQueueSet that is used to manage RSet updates 260 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set); 261 262 updateRS(&into_cset_dcq, worker_i); 263 size_t cards_scanned = scanRS(oc, heap_region_codeblobs, worker_i); 264 265 // We now clear the cached values of _cset_rs_update_cl for this worker 266 _cset_rs_update_cl[worker_i] = NULL; 267 return cards_scanned; 268 } 269 270 void G1RemSet::prepare_for_oops_into_collection_set_do() { 271 _g1->set_refine_cte_cl_concurrency(false); 272 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 273 dcqs.concatenate_logs(); 274 } 275 276 void G1RemSet::cleanup_after_oops_into_collection_set_do() { 277 // Cleanup after copy 278 _g1->set_refine_cte_cl_concurrency(true); 279 // Set all cards back to clean. 280 _g1->cleanUpCardTable(); 281 282 DirtyCardQueueSet& into_cset_dcqs = _into_cset_dirty_card_queue_set; 283 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num(); 284 285 if (_g1->evacuation_failed()) { 286 double restore_remembered_set_start = os::elapsedTime(); 287 288 // Restore remembered sets for the regions pointing into the collection set. 289 // We just need to transfer the completed buffers from the DirtyCardQueueSet 290 // used to hold cards that contain references that point into the collection set 291 // to the DCQS used to hold the deferred RS updates. 292 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs); 293 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0); 294 } 295 296 // Free any completed buffers in the DirtyCardQueueSet used to hold cards 297 // which contain references that point into the collection. 298 _into_cset_dirty_card_queue_set.clear(); 299 assert(_into_cset_dirty_card_queue_set.completed_buffers_num() == 0, 300 "all buffers should be freed"); 301 _into_cset_dirty_card_queue_set.clear_n_completed_buffers(); 302 } 303 304 class ScrubRSClosure: public HeapRegionClosure { 305 G1CollectedHeap* _g1h; 306 BitMap* _region_bm; 307 BitMap* _card_bm; 308 CardTableModRefBS* _ctbs; 309 public: 310 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) : 311 _g1h(G1CollectedHeap::heap()), 312 _region_bm(region_bm), _card_bm(card_bm), 313 _ctbs(_g1h->g1_barrier_set()) {} 314 315 bool doHeapRegion(HeapRegion* r) { 316 if (!r->is_continues_humongous()) { 317 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm); 318 } 319 return false; 320 } 321 }; 322 323 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) { 324 ScrubRSClosure scrub_cl(region_bm, card_bm); 325 _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer); 326 } 327 328 G1TriggerClosure::G1TriggerClosure() : 329 _triggered(false) { } 330 331 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl, 332 OopClosure* oop_cl) : 333 _trigger_cl(t_cl), _oop_cl(oop_cl) { } 334 335 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) : 336 _c1(c1), _c2(c2) { } 337 338 G1UpdateRSOrPushRefOopClosure:: 339 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h, 340 G1RemSet* rs, 341 G1ParPushHeapRSClosure* push_ref_cl, 342 bool record_refs_into_cset, 343 uint worker_i) : 344 _g1(g1h), _g1_rem_set(rs), _from(NULL), 345 _record_refs_into_cset(record_refs_into_cset), 346 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { } 347 348 // Returns true if the given card contains references that point 349 // into the collection set, if we're checking for such references; 350 // false otherwise. 351 352 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i, 353 bool check_for_refs_into_cset) { 354 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)), 355 "Card at " PTR_FORMAT " index " SIZE_FORMAT " representing heap at " PTR_FORMAT " (%u) must be in committed heap", 356 p2i(card_ptr), 357 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)), 358 p2i(_ct_bs->addr_for(card_ptr)), 359 _g1->addr_to_region(_ct_bs->addr_for(card_ptr))); 360 361 // If the card is no longer dirty, nothing to do. 362 if (*card_ptr != CardTableModRefBS::dirty_card_val()) { 363 // No need to return that this card contains refs that point 364 // into the collection set. 365 return false; 366 } 367 368 // Construct the region representing the card. 369 HeapWord* start = _ct_bs->addr_for(card_ptr); 370 // And find the region containing it. 371 HeapRegion* r = _g1->heap_region_containing(start); 372 373 // Why do we have to check here whether a card is on a young region, 374 // given that we dirty young regions and, as a result, the 375 // post-barrier is supposed to filter them out and never to enqueue 376 // them? When we allocate a new region as the "allocation region" we 377 // actually dirty its cards after we release the lock, since card 378 // dirtying while holding the lock was a performance bottleneck. So, 379 // as a result, it is possible for other threads to actually 380 // allocate objects in the region (after the acquire the lock) 381 // before all the cards on the region are dirtied. This is unlikely, 382 // and it doesn't happen often, but it can happen. So, the extra 383 // check below filters out those cards. 384 if (r->is_young()) { 385 return false; 386 } 387 388 // While we are processing RSet buffers during the collection, we 389 // actually don't want to scan any cards on the collection set, 390 // since we don't want to update remembered sets with entries that 391 // point into the collection set, given that live objects from the 392 // collection set are about to move and such entries will be stale 393 // very soon. This change also deals with a reliability issue which 394 // involves scanning a card in the collection set and coming across 395 // an array that was being chunked and looking malformed. Note, 396 // however, that if evacuation fails, we have to scan any objects 397 // that were not moved and create any missing entries. 398 if (r->in_collection_set()) { 399 return false; 400 } 401 402 // The result from the hot card cache insert call is either: 403 // * pointer to the current card 404 // (implying that the current card is not 'hot'), 405 // * null 406 // (meaning we had inserted the card ptr into the "hot" card cache, 407 // which had some headroom), 408 // * a pointer to a "hot" card that was evicted from the "hot" cache. 409 // 410 411 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache(); 412 if (hot_card_cache->use_cache()) { 413 assert(!check_for_refs_into_cset, "sanity"); 414 assert(!SafepointSynchronize::is_at_safepoint(), "sanity"); 415 416 card_ptr = hot_card_cache->insert(card_ptr); 417 if (card_ptr == NULL) { 418 // There was no eviction. Nothing to do. 419 return false; 420 } 421 422 start = _ct_bs->addr_for(card_ptr); 423 r = _g1->heap_region_containing(start); 424 425 // Checking whether the region we got back from the cache 426 // is young here is inappropriate. The region could have been 427 // freed, reallocated and tagged as young while in the cache. 428 // Hence we could see its young type change at any time. 429 } 430 431 // Don't use addr_for(card_ptr + 1) which can ask for 432 // a card beyond the heap. This is not safe without a perm 433 // gen at the upper end of the heap. 434 HeapWord* end = start + CardTableModRefBS::card_size_in_words; 435 MemRegion dirtyRegion(start, end); 436 437 G1ParPushHeapRSClosure* oops_in_heap_closure = NULL; 438 if (check_for_refs_into_cset) { 439 // ConcurrentG1RefineThreads have worker numbers larger than what 440 // _cset_rs_update_cl[] is set up to handle. But those threads should 441 // only be active outside of a collection which means that when they 442 // reach here they should have check_for_refs_into_cset == false. 443 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length"); 444 oops_in_heap_closure = _cset_rs_update_cl[worker_i]; 445 } 446 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1, 447 _g1->g1_rem_set(), 448 oops_in_heap_closure, 449 check_for_refs_into_cset, 450 worker_i); 451 update_rs_oop_cl.set_from(r); 452 453 G1TriggerClosure trigger_cl; 454 FilterIntoCSClosure into_cs_cl(_g1, &trigger_cl); 455 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl); 456 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl); 457 458 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, 459 (check_for_refs_into_cset ? 460 (OopClosure*)&mux : 461 (OopClosure*)&update_rs_oop_cl)); 462 463 // The region for the current card may be a young region. The 464 // current card may have been a card that was evicted from the 465 // card cache. When the card was inserted into the cache, we had 466 // determined that its region was non-young. While in the cache, 467 // the region may have been freed during a cleanup pause, reallocated 468 // and tagged as young. 469 // 470 // We wish to filter out cards for such a region but the current 471 // thread, if we're running concurrently, may "see" the young type 472 // change at any time (so an earlier "is_young" check may pass or 473 // fail arbitrarily). We tell the iteration code to perform this 474 // filtering when it has been determined that there has been an actual 475 // allocation in this region and making it safe to check the young type. 476 bool filter_young = true; 477 478 HeapWord* stop_point = 479 r->oops_on_card_seq_iterate_careful(dirtyRegion, 480 &filter_then_update_rs_oop_cl, 481 filter_young, 482 card_ptr); 483 484 // If stop_point is non-null, then we encountered an unallocated region 485 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the 486 // card and re-enqueue: if we put off the card until a GC pause, then the 487 // unallocated portion will be filled in. Alternatively, we might try 488 // the full complexity of the technique used in "regular" precleaning. 489 if (stop_point != NULL) { 490 // The card might have gotten re-dirtied and re-enqueued while we 491 // worked. (In fact, it's pretty likely.) 492 if (*card_ptr != CardTableModRefBS::dirty_card_val()) { 493 *card_ptr = CardTableModRefBS::dirty_card_val(); 494 MutexLockerEx x(Shared_DirtyCardQ_lock, 495 Mutex::_no_safepoint_check_flag); 496 DirtyCardQueue* sdcq = 497 JavaThread::dirty_card_queue_set().shared_dirty_card_queue(); 498 sdcq->enqueue(card_ptr); 499 } 500 } else { 501 _conc_refine_cards++; 502 } 503 504 // This gets set to true if the card being refined has 505 // references that point into the collection set. 506 bool has_refs_into_cset = trigger_cl.triggered(); 507 508 // We should only be detecting that the card contains references 509 // that point into the collection set if the current thread is 510 // a GC worker thread. 511 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(), 512 "invalid result at non safepoint"); 513 514 return has_refs_into_cset; 515 } 516 517 void G1RemSet::print_periodic_summary_info(const char* header, uint period_count) { 518 if ((G1SummarizeRSetStatsPeriod > 0) && log_is_enabled(Trace, gc, remset) && 519 (period_count % G1SummarizeRSetStatsPeriod == 0)) { 520 521 if (!_prev_period_summary.initialized()) { 522 _prev_period_summary.initialize(this); 523 } 524 525 G1RemSetSummary current; 526 current.initialize(this); 527 _prev_period_summary.subtract_from(¤t); 528 529 LogHandle(gc, remset) log; 530 log.trace("%s", header); 531 ResourceMark rm; 532 _prev_period_summary.print_on(log.trace_stream()); 533 534 _prev_period_summary.set(¤t); 535 } 536 } 537 538 void G1RemSet::print_summary_info() { 539 LogHandle(gc, remset, exit) log; 540 if (log.is_trace()) { 541 log.trace(" Cumulative RS summary"); 542 G1RemSetSummary current; 543 current.initialize(this); 544 ResourceMark rm; 545 current.print_on(log.trace_stream()); 546 } 547 } 548 549 void G1RemSet::prepare_for_verify() { 550 if (G1HRRSFlushLogBuffersOnVerify && 551 (VerifyBeforeGC || VerifyAfterGC) 552 && (!_g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC)) { 553 cleanupHRRS(); 554 _g1->set_refine_cte_cl_concurrency(false); 555 if (SafepointSynchronize::is_at_safepoint()) { 556 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); 557 dcqs.concatenate_logs(); 558 } 559 560 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache(); 561 bool use_hot_card_cache = hot_card_cache->use_cache(); 562 hot_card_cache->set_use_cache(false); 563 564 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set); 565 updateRS(&into_cset_dcq, 0); 566 _into_cset_dirty_card_queue_set.clear(); 567 568 hot_card_cache->set_use_cache(use_hot_card_cache); 569 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed"); 570 } 571 }