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/heapRegionManager.inline.hpp"
36 #include "gc/g1/heapRegionRemSet.hpp"
37 #include "memory/iterator.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "utilities/globalDefinitions.hpp"
40 #include "utilities/intHisto.hpp"
41 #include "utilities/stack.inline.hpp"
42
43 G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
44 : _g1(g1), _conc_refine_cards(0),
45 _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
46 _cg1r(g1->concurrent_g1_refine()),
47 _cset_rs_update_cl(NULL),
48 _prev_period_summary()
49 {
50 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, n_workers(), mtGC);
51 for (uint i = 0; i < n_workers(); i++) {
52 _cset_rs_update_cl[i] = NULL;
53 }
54 if (log_is_enabled(Trace, gc, remset)) {
55 _prev_period_summary.initialize(this);
56 }
57 }
58
59 G1RemSet::~G1RemSet() {
60 for (uint i = 0; i < n_workers(); i++) {
61 assert(_cset_rs_update_cl[i] == NULL, "it should be");
62 }
63 FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl);
64 }
65
66 class ScanRSClosure : public HeapRegionClosure {
67 size_t _cards_done, _cards;
68 G1CollectedHeap* _g1h;
69
70 G1ParPushHeapRSClosure* _oc;
71 CodeBlobClosure* _code_root_cl;
72
73 G1BlockOffsetSharedArray* _bot_shared;
74 G1SATBCardTableModRefBS *_ct_bs;
75
76 double _strong_code_root_scan_time_sec;
77 uint _worker_i;
78 size_t _block_size;
79 bool _try_claimed;
80
81 public:
82 ScanRSClosure(G1ParPushHeapRSClosure* oc,
83 CodeBlobClosure* code_root_cl,
84 uint worker_i) :
85 _oc(oc),
86 _code_root_cl(code_root_cl),
87 _strong_code_root_scan_time_sec(0.0),
88 _cards(0),
89 _cards_done(0),
90 _worker_i(worker_i),
91 _try_claimed(false)
92 {
93 _g1h = G1CollectedHeap::heap();
94 _bot_shared = _g1h->bot_shared();
95 _ct_bs = _g1h->g1_barrier_set();
96 _block_size = MAX2<size_t>(G1RSetScanBlockSize, 1);
97 }
98
99 void set_try_claimed() { _try_claimed = true; }
100
101 void scanCard(size_t index, HeapRegion *r) {
102 // Stack allocate the DirtyCardToOopClosure instance
103 HeapRegionDCTOC cl(_g1h, r, _oc,
104 CardTableModRefBS::Precise);
105
106 // Set the "from" region in the closure.
107 _oc->set_region(r);
108 MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words);
109 MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
110 MemRegion mr = pre_gc_allocated.intersection(card_region);
111 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
112 // We make the card as "claimed" lazily (so races are possible
113 // but they're benign), which reduces the number of duplicate
114 // scans (the rsets of the regions in the cset can intersect).
115 _ct_bs->set_card_claimed(index);
116 _cards_done++;
117 cl.do_MemRegion(mr);
118 }
119 }
120
121 void scan_strong_code_roots(HeapRegion* r) {
122 double scan_start = os::elapsedTime();
123 r->strong_code_roots_do(_code_root_cl);
124 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
125 }
126
127 bool doHeapRegion(HeapRegion* r) {
128 assert(r->in_collection_set(), "should only be called on elements of CS.");
129 HeapRegionRemSet* hrrs = r->rem_set();
130 if (hrrs->iter_is_complete()) return false; // All done.
131 if (!_try_claimed && !hrrs->claim_iter()) return false;
132 // If we ever free the collection set concurrently, we should also
133 // clear the card table concurrently therefore we won't need to
134 // add regions of the collection set to the dirty cards region.
135 _g1h->push_dirty_cards_region(r);
136 // If we didn't return above, then
137 // _try_claimed || r->claim_iter()
138 // is true: either we're supposed to work on claimed-but-not-complete
139 // regions, or we successfully claimed the region.
140
141 HeapRegionRemSetIterator iter(hrrs);
142 size_t card_index;
143
144 // We claim cards in block so as to reduce the contention. The block size is determined by
145 // the G1RSetScanBlockSize parameter.
146 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
147 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
148 if (current_card >= jump_to_card + _block_size) {
149 jump_to_card = hrrs->iter_claimed_next(_block_size);
150 }
151 if (current_card < jump_to_card) continue;
152 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
153 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
154 _cards++;
155
156 if (!card_region->is_on_dirty_cards_region_list()) {
157 _g1h->push_dirty_cards_region(card_region);
158 }
159
160 // If the card is dirty, then we will scan it during updateRS.
161 if (!card_region->in_collection_set() &&
162 !_ct_bs->is_card_dirty(card_index)) {
163 scanCard(card_index, card_region);
164 }
165 }
166 if (!_try_claimed) {
167 // Scan the strong code root list attached to the current region
168 scan_strong_code_roots(r);
169
170 hrrs->set_iter_complete();
171 }
172 return false;
173 }
174
175 double strong_code_root_scan_time_sec() {
176 return _strong_code_root_scan_time_sec;
177 }
178
179 size_t cards_done() { return _cards_done;}
180 size_t cards_looked_up() { return _cards;}
181 };
182
183 size_t G1RemSet::scanRS(G1ParPushHeapRSClosure* oc,
184 CodeBlobClosure* heap_region_codeblobs,
185 uint worker_i) {
186 double rs_time_start = os::elapsedTime();
187
188 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
189
190 ScanRSClosure scanRScl(oc, heap_region_codeblobs, worker_i);
191
192 _g1->collection_set_iterate_from(startRegion, &scanRScl);
193 scanRScl.set_try_claimed();
194 _g1->collection_set_iterate_from(startRegion, &scanRScl);
195
196 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
197 - scanRScl.strong_code_root_scan_time_sec();
198
199 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::ScanRS, worker_i, scan_rs_time_sec);
200 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::CodeRoots, worker_i, scanRScl.strong_code_root_scan_time_sec());
201
202 return scanRScl.cards_done();
203 }
204
205 // Closure used for updating RSets and recording references that
206 // point into the collection set. Only called during an
207 // evacuation pause.
208
209 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
210 G1RemSet* _g1rs;
211 DirtyCardQueue* _into_cset_dcq;
212 public:
213 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
214 DirtyCardQueue* into_cset_dcq) :
215 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
216 {}
217
218 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
219 // The only time we care about recording cards that
220 // contain references that point into the collection set
221 // is during RSet updating within an evacuation pause.
222 // In this case worker_i should be the id of a GC worker thread.
223 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
224 assert(worker_i < ParallelGCThreads, "should be a GC worker");
225
226 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
227 // 'card_ptr' contains references that point into the collection
228 // set. We need to record the card in the DCQS
229 // (G1CollectedHeap::into_cset_dirty_card_queue_set())
230 // that's used for that purpose.
231 //
232 // Enqueue the card
233 _into_cset_dcq->enqueue(card_ptr);
234 }
235 return true;
236 }
237 };
238
239 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
240 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
241
242 G1GCParPhaseTimesTracker x(_g1p->phase_times(), G1GCPhaseTimes::UpdateRS, worker_i);
243 {
244 // Apply the closure to the entries of the hot card cache.
245 G1GCParPhaseTimesTracker y(_g1p->phase_times(), G1GCPhaseTimes::ScanHCC, worker_i);
246 _g1->iterate_hcc_closure(&into_cset_update_rs_cl, worker_i);
247 }
248 // Apply the closure to all remaining log entries.
249 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, worker_i);
250 }
251
252 void G1RemSet::cleanupHRRS() {
253 HeapRegionRemSet::cleanup();
254 }
255
256 size_t G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc,
257 CodeBlobClosure* heap_region_codeblobs,
258 uint worker_i) {
259 // We cache the value of 'oc' closure into the appropriate slot in the
260 // _cset_rs_update_cl for this worker
261 assert(worker_i < n_workers(), "sanity");
262 _cset_rs_update_cl[worker_i] = oc;
263
264 // A DirtyCardQueue that is used to hold cards containing references
265 // that point into the collection set. This DCQ is associated with a
266 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
267 // circumstances (i.e. the pause successfully completes), these cards
268 // are just discarded (there's no need to update the RSets of regions
269 // that were in the collection set - after the pause these regions
270 // are wholly 'free' of live objects. In the event of an evacuation
271 // failure the cards/buffers in this queue set are passed to the
272 // DirtyCardQueueSet that is used to manage RSet updates
273 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
274
275 updateRS(&into_cset_dcq, worker_i);
276 size_t cards_scanned = scanRS(oc, heap_region_codeblobs, worker_i);
277
278 // We now clear the cached values of _cset_rs_update_cl for this worker
279 _cset_rs_update_cl[worker_i] = NULL;
280 return cards_scanned;
281 }
282
283 void G1RemSet::prepare_for_oops_into_collection_set_do() {
284 cleanupHRRS();
285 _g1->set_refine_cte_cl_concurrency(false);
286 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
287 dcqs.concatenate_logs();
288 }
289
290 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
291 // Cleanup after copy
292 _g1->set_refine_cte_cl_concurrency(true);
293 // Set all cards back to clean.
294 _g1->cleanUpCardTable();
295
296 DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
297 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
298
299 if (_g1->evacuation_failed()) {
300 double restore_remembered_set_start = os::elapsedTime();
301
302 // Restore remembered sets for the regions pointing into the collection set.
303 // We just need to transfer the completed buffers from the DirtyCardQueueSet
304 // used to hold cards that contain references that point into the collection set
305 // to the DCQS used to hold the deferred RS updates.
306 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
307 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
308 }
309
310 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
311 // which contain references that point into the collection.
312 _g1->into_cset_dirty_card_queue_set().clear();
313 assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
314 "all buffers should be freed");
315 _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
316 }
317
318 class ScrubRSClosure: public HeapRegionClosure {
319 G1CollectedHeap* _g1h;
320 BitMap* _region_bm;
321 BitMap* _card_bm;
322 CardTableModRefBS* _ctbs;
323 public:
324 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
325 _g1h(G1CollectedHeap::heap()),
326 _region_bm(region_bm), _card_bm(card_bm),
327 _ctbs(_g1h->g1_barrier_set()) {}
328
329 bool doHeapRegion(HeapRegion* r) {
330 if (!r->is_continues_humongous()) {
331 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
332 }
333 return false;
334 }
335 };
336
337 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
338 ScrubRSClosure scrub_cl(region_bm, card_bm);
339 _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
340 }
341
342 G1TriggerClosure::G1TriggerClosure() :
343 _triggered(false) { }
344
345 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
346 OopClosure* oop_cl) :
347 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
348
349 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
350 _c1(c1), _c2(c2) { }
351
352 G1UpdateRSOrPushRefOopClosure::
353 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
354 G1RemSet* rs,
355 G1ParPushHeapRSClosure* push_ref_cl,
356 bool record_refs_into_cset,
357 uint worker_i) :
358 _g1(g1h), _g1_rem_set(rs), _from(NULL),
359 _record_refs_into_cset(record_refs_into_cset),
360 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
361
362 // Returns true if the given card contains references that point
363 // into the collection set, if we're checking for such references;
364 // false otherwise.
365
366 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
367 bool check_for_refs_into_cset) {
368 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
369 "Card at " PTR_FORMAT " index " SIZE_FORMAT " representing heap at " PTR_FORMAT " (%u) must be in committed heap",
370 p2i(card_ptr),
371 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
372 p2i(_ct_bs->addr_for(card_ptr)),
373 _g1->addr_to_region(_ct_bs->addr_for(card_ptr)));
374
375 // If the card is no longer dirty, nothing to do.
376 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
377 // No need to return that this card contains refs that point
378 // into the collection set.
379 return false;
380 }
381
382 // Construct the region representing the card.
383 HeapWord* start = _ct_bs->addr_for(card_ptr);
384 // And find the region containing it.
385 HeapRegion* r = _g1->heap_region_containing(start);
386
387 // Why do we have to check here whether a card is on a young region,
388 // given that we dirty young regions and, as a result, the
389 // post-barrier is supposed to filter them out and never to enqueue
390 // them? When we allocate a new region as the "allocation region" we
391 // actually dirty its cards after we release the lock, since card
392 // dirtying while holding the lock was a performance bottleneck. So,
393 // as a result, it is possible for other threads to actually
394 // allocate objects in the region (after the acquire the lock)
395 // before all the cards on the region are dirtied. This is unlikely,
396 // and it doesn't happen often, but it can happen. So, the extra
397 // check below filters out those cards.
398 if (r->is_young()) {
399 return false;
400 }
401
402 // While we are processing RSet buffers during the collection, we
403 // actually don't want to scan any cards on the collection set,
404 // since we don't want to update remembered sets with entries that
405 // point into the collection set, given that live objects from the
406 // collection set are about to move and such entries will be stale
407 // very soon. This change also deals with a reliability issue which
408 // involves scanning a card in the collection set and coming across
409 // an array that was being chunked and looking malformed. Note,
410 // however, that if evacuation fails, we have to scan any objects
411 // that were not moved and create any missing entries.
412 if (r->in_collection_set()) {
413 return false;
414 }
415
416 // The result from the hot card cache insert call is either:
417 // * pointer to the current card
418 // (implying that the current card is not 'hot'),
419 // * null
420 // (meaning we had inserted the card ptr into the "hot" card cache,
421 // which had some headroom),
422 // * a pointer to a "hot" card that was evicted from the "hot" cache.
423 //
424
425 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
426 if (hot_card_cache->use_cache()) {
427 assert(!check_for_refs_into_cset, "sanity");
428 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
429
430 card_ptr = hot_card_cache->insert(card_ptr);
431 if (card_ptr == NULL) {
432 // There was no eviction. Nothing to do.
433 return false;
434 }
435
436 start = _ct_bs->addr_for(card_ptr);
437 r = _g1->heap_region_containing(start);
438
439 // Checking whether the region we got back from the cache
440 // is young here is inappropriate. The region could have been
441 // freed, reallocated and tagged as young while in the cache.
442 // Hence we could see its young type change at any time.
443 }
444
445 // Don't use addr_for(card_ptr + 1) which can ask for
446 // a card beyond the heap. This is not safe without a perm
447 // gen at the upper end of the heap.
448 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
449 MemRegion dirtyRegion(start, end);
450
451 G1ParPushHeapRSClosure* oops_in_heap_closure = NULL;
452 if (check_for_refs_into_cset) {
453 // ConcurrentG1RefineThreads have worker numbers larger than what
454 // _cset_rs_update_cl[] is set up to handle. But those threads should
455 // only be active outside of a collection which means that when they
456 // reach here they should have check_for_refs_into_cset == false.
457 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
458 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
459 }
460 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
461 _g1->g1_rem_set(),
462 oops_in_heap_closure,
463 check_for_refs_into_cset,
464 worker_i);
465 update_rs_oop_cl.set_from(r);
466
467 G1TriggerClosure trigger_cl;
468 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
469 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
470 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
471
472 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
473 (check_for_refs_into_cset ?
474 (OopClosure*)&mux :
475 (OopClosure*)&update_rs_oop_cl));
476
477 // The region for the current card may be a young region. The
478 // current card may have been a card that was evicted from the
479 // card cache. When the card was inserted into the cache, we had
480 // determined that its region was non-young. While in the cache,
481 // the region may have been freed during a cleanup pause, reallocated
482 // and tagged as young.
483 //
484 // We wish to filter out cards for such a region but the current
485 // thread, if we're running concurrently, may "see" the young type
486 // change at any time (so an earlier "is_young" check may pass or
487 // fail arbitrarily). We tell the iteration code to perform this
488 // filtering when it has been determined that there has been an actual
489 // allocation in this region and making it safe to check the young type.
490 bool filter_young = true;
491
492 HeapWord* stop_point =
493 r->oops_on_card_seq_iterate_careful(dirtyRegion,
494 &filter_then_update_rs_oop_cl,
495 filter_young,
496 card_ptr);
497
498 // If stop_point is non-null, then we encountered an unallocated region
499 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
500 // card and re-enqueue: if we put off the card until a GC pause, then the
501 // unallocated portion will be filled in. Alternatively, we might try
502 // the full complexity of the technique used in "regular" precleaning.
503 if (stop_point != NULL) {
504 // The card might have gotten re-dirtied and re-enqueued while we
505 // worked. (In fact, it's pretty likely.)
506 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
507 *card_ptr = CardTableModRefBS::dirty_card_val();
508 MutexLockerEx x(Shared_DirtyCardQ_lock,
509 Mutex::_no_safepoint_check_flag);
510 DirtyCardQueue* sdcq =
511 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
512 sdcq->enqueue(card_ptr);
513 }
514 } else {
515 _conc_refine_cards++;
516 }
517
518 // This gets set to true if the card being refined has
519 // references that point into the collection set.
520 bool has_refs_into_cset = trigger_cl.triggered();
521
522 // We should only be detecting that the card contains references
523 // that point into the collection set if the current thread is
524 // a GC worker thread.
525 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
526 "invalid result at non safepoint");
527
528 return has_refs_into_cset;
529 }
530
531 void G1RemSet::print_periodic_summary_info(const char* header, uint period_count) {
532 if ((G1SummarizeRSetStatsPeriod > 0) && log_is_enabled(Trace, gc, remset) &&
533 (period_count % G1SummarizeRSetStatsPeriod == 0)) {
534
535 if (!_prev_period_summary.initialized()) {
536 _prev_period_summary.initialize(this);
537 }
538
539 G1RemSetSummary current;
540 current.initialize(this);
541 _prev_period_summary.subtract_from(¤t);
542
543 LogHandle(gc, remset) log;
544 log.trace("%s", header);
545 ResourceMark rm;
546 _prev_period_summary.print_on(log.trace_stream());
547
548 _prev_period_summary.set(¤t);
549 }
550 }
551
552 void G1RemSet::print_summary_info() {
553 LogHandle(gc, remset, exit) log;
554 if (log.is_trace()) {
555 log.trace(" Cumulative RS summary");
556 G1RemSetSummary current;
557 current.initialize(this);
558 ResourceMark rm;
559 current.print_on(log.trace_stream());
560 }
561 }
562
563 void G1RemSet::prepare_for_verify() {
564 if (G1HRRSFlushLogBuffersOnVerify &&
565 (VerifyBeforeGC || VerifyAfterGC)
566 && (!_g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC)) {
567 cleanupHRRS();
568 _g1->set_refine_cte_cl_concurrency(false);
569 if (SafepointSynchronize::is_at_safepoint()) {
570 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
571 dcqs.concatenate_logs();
572 }
573
574 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
575 bool use_hot_card_cache = hot_card_cache->use_cache();
576 hot_card_cache->set_use_cache(false);
577
578 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
579 updateRS(&into_cset_dcq, 0);
580 _g1->into_cset_dirty_card_queue_set().clear();
581
582 hot_card_cache->set_use_cache(use_hot_card_cache);
583 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
584 }
585 }