1 /*
2 * Copyright (c) 2001, 2016, 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/dirtyCardQueue.hpp"
29 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
30 #include "gc/g1/g1CollectedHeap.inline.hpp"
31 #include "gc/g1/g1CollectorPolicy.hpp"
32 #include "gc/g1/g1FromCardCache.hpp"
33 #include "gc/g1/g1GCPhaseTimes.hpp"
34 #include "gc/g1/g1HotCardCache.hpp"
35 #include "gc/g1/g1OopClosures.inline.hpp"
36 #include "gc/g1/g1RemSet.inline.hpp"
37 #include "gc/g1/heapRegion.inline.hpp"
38 #include "gc/g1/heapRegionManager.inline.hpp"
39 #include "gc/g1/heapRegionRemSet.hpp"
40 #include "memory/iterator.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "utilities/globalDefinitions.hpp"
43 #include "utilities/intHisto.hpp"
44 #include "utilities/stack.inline.hpp"
45
46 G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs) :
47 _g1(g1),
48 _conc_refine_cards(0),
49 _ct_bs(ct_bs),
50 _g1p(_g1->g1_policy()),
51 _cg1r(g1->concurrent_g1_refine()),
52 _cset_rs_update_cl(NULL),
53 _prev_period_summary(),
54 _into_cset_dirty_card_queue_set(false)
55 {
56 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, n_workers(), mtGC);
57 for (uint i = 0; i < n_workers(); i++) {
58 _cset_rs_update_cl[i] = NULL;
59 }
60 if (log_is_enabled(Trace, gc, remset)) {
61 _prev_period_summary.initialize(this);
62 }
63 // Initialize the card queue set used to hold cards containing
64 // references into the collection set.
65 _into_cset_dirty_card_queue_set.initialize(NULL, // Should never be called by the Java code
66 DirtyCardQ_CBL_mon,
67 DirtyCardQ_FL_lock,
68 -1, // never trigger processing
69 -1, // no limit on length
70 Shared_DirtyCardQ_lock,
71 &JavaThread::dirty_card_queue_set());
72 }
73
74 G1RemSet::~G1RemSet() {
75 for (uint i = 0; i < n_workers(); i++) {
76 assert(_cset_rs_update_cl[i] == NULL, "it should be");
77 }
78 FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl);
79 }
80
81 uint G1RemSet::num_par_rem_sets() {
82 return MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), ParallelGCThreads);
83 }
84
85 void G1RemSet::initialize(uint max_regions) {
86 G1FromCardCache::initialize(num_par_rem_sets(), max_regions);
87 }
88
89 ScanRSClosure::ScanRSClosure(G1ParPushHeapRSClosure* oc,
90 CodeBlobClosure* code_root_cl,
91 uint worker_i) :
92 _oc(oc),
93 _code_root_cl(code_root_cl),
94 _strong_code_root_scan_time_sec(0.0),
95 _cards(0),
96 _cards_done(0),
97 _worker_i(worker_i),
98 _try_claimed(false) {
99 _g1h = G1CollectedHeap::heap();
100 _bot = _g1h->bot();
101 _ct_bs = _g1h->g1_barrier_set();
102 _block_size = MAX2<size_t>(G1RSetScanBlockSize, 1);
103 }
104
105 void ScanRSClosure::scanCard(size_t index, HeapRegion *r) {
106 // Stack allocate the DirtyCardToOopClosure instance
107 HeapRegionDCTOC cl(_g1h, r, _oc,
108 CardTableModRefBS::Precise);
109
110 // Set the "from" region in the closure.
111 _oc->set_region(r);
112 MemRegion card_region(_bot->address_for_index(index), BOTConstants::N_words);
113 MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
114 MemRegion mr = pre_gc_allocated.intersection(card_region);
115 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
116 // We make the card as "claimed" lazily (so races are possible
117 // but they're benign), which reduces the number of duplicate
118 // scans (the rsets of the regions in the cset can intersect).
119 _ct_bs->set_card_claimed(index);
120 _cards_done++;
121 cl.do_MemRegion(mr);
122 }
123 }
124
125 void ScanRSClosure::scan_strong_code_roots(HeapRegion* r) {
126 double scan_start = os::elapsedTime();
127 r->strong_code_roots_do(_code_root_cl);
128 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
129 }
130
131 bool ScanRSClosure::doHeapRegion(HeapRegion* r) {
132 assert(r->in_collection_set(), "should only be called on elements of CS.");
133 HeapRegionRemSet* hrrs = r->rem_set();
134 if (hrrs->iter_is_complete()) return false; // All done.
135 if (!_try_claimed && !hrrs->claim_iter()) return false;
136 // If we ever free the collection set concurrently, we should also
137 // clear the card table concurrently therefore we won't need to
138 // add regions of the collection set to the dirty cards region.
139 _g1h->push_dirty_cards_region(r);
140 // If we didn't return above, then
141 // _try_claimed || r->claim_iter()
142 // is true: either we're supposed to work on claimed-but-not-complete
143 // regions, or we successfully claimed the region.
144
145 HeapRegionRemSetIterator iter(hrrs);
146 size_t card_index;
147
148 // We claim cards in block so as to reduce the contention. The block size is determined by
149 // the G1RSetScanBlockSize parameter.
150 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
151 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
152 if (current_card >= jump_to_card + _block_size) {
153 jump_to_card = hrrs->iter_claimed_next(_block_size);
154 }
155 if (current_card < jump_to_card) continue;
156 HeapWord* card_start = _g1h->bot()->address_for_index(card_index);
157
158 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
159 _cards++;
160
161 if (!card_region->is_on_dirty_cards_region_list()) {
162 _g1h->push_dirty_cards_region(card_region);
163 }
164
165 // If the card is dirty, then we will scan it during updateRS.
166 if (!card_region->in_collection_set() &&
167 !_ct_bs->is_card_dirty(card_index)) {
168 scanCard(card_index, card_region);
169 }
170 }
171 if (!_try_claimed) {
172 // Scan the strong code root list attached to the current region
173 scan_strong_code_roots(r);
174
175 hrrs->set_iter_complete();
176 }
177 return false;
178 }
179
180 size_t G1RemSet::scanRS(G1ParPushHeapRSClosure* oc,
181 CodeBlobClosure* heap_region_codeblobs,
182 uint worker_i) {
183 double rs_time_start = os::elapsedTime();
184
185 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
186
187 ScanRSClosure scanRScl(oc, heap_region_codeblobs, worker_i);
188
189 _g1->collection_set_iterate_from(startRegion, &scanRScl);
190 scanRScl.set_try_claimed();
191 _g1->collection_set_iterate_from(startRegion, &scanRScl);
192
193 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
194 - scanRScl.strong_code_root_scan_time_sec();
195
196 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::ScanRS, worker_i, scan_rs_time_sec);
197 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::CodeRoots, worker_i, scanRScl.strong_code_root_scan_time_sec());
198
199 return scanRScl.cards_done();
200 }
201
202 // Closure used for updating RSets and recording references that
203 // point into the collection set. Only called during an
204 // evacuation pause.
205
206 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
207 G1RemSet* _g1rs;
208 DirtyCardQueue* _into_cset_dcq;
209 public:
210 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
211 DirtyCardQueue* into_cset_dcq) :
212 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
213 {}
214
215 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
216 // The only time we care about recording cards that
217 // contain references that point into the collection set
218 // is during RSet updating within an evacuation pause.
219 // In this case worker_i should be the id of a GC worker thread.
220 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
221 assert(worker_i < ParallelGCThreads, "should be a GC worker");
222
223 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
224 // 'card_ptr' contains references that point into the collection
225 // set. We need to record the card in the DCQS
226 // (_into_cset_dirty_card_queue_set)
227 // that's used for that purpose.
228 //
229 // Enqueue the card
230 _into_cset_dcq->enqueue(card_ptr);
231 }
232 return true;
233 }
234 };
235
236 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
237 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
238
239 G1GCParPhaseTimesTracker x(_g1p->phase_times(), G1GCPhaseTimes::UpdateRS, worker_i);
240 {
241 // Apply the closure to the entries of the hot card cache.
242 G1GCParPhaseTimesTracker y(_g1p->phase_times(), G1GCPhaseTimes::ScanHCC, worker_i);
243 _g1->iterate_hcc_closure(&into_cset_update_rs_cl, worker_i);
244 }
245 // Apply the closure to all remaining log entries.
246 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, worker_i);
247 }
248
249 void G1RemSet::cleanupHRRS() {
250 HeapRegionRemSet::cleanup();
251 }
252
253 size_t G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc,
254 CodeBlobClosure* heap_region_codeblobs,
255 uint worker_i) {
256 // We cache the value of 'oc' closure into the appropriate slot in the
257 // _cset_rs_update_cl for this worker
258 assert(worker_i < n_workers(), "sanity");
259 _cset_rs_update_cl[worker_i] = oc;
260
261 // A DirtyCardQueue that is used to hold cards containing references
262 // that point into the collection set. This DCQ is associated with a
263 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
264 // circumstances (i.e. the pause successfully completes), these cards
265 // are just discarded (there's no need to update the RSets of regions
266 // that were in the collection set - after the pause these regions
267 // are wholly 'free' of live objects. In the event of an evacuation
268 // failure the cards/buffers in this queue set are passed to the
269 // DirtyCardQueueSet that is used to manage RSet updates
270 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set);
271
272 updateRS(&into_cset_dcq, worker_i);
273 size_t cards_scanned = scanRS(oc, heap_region_codeblobs, worker_i);
274
275 // We now clear the cached values of _cset_rs_update_cl for this worker
276 _cset_rs_update_cl[worker_i] = NULL;
277 return cards_scanned;
278 }
279
280 void G1RemSet::prepare_for_oops_into_collection_set_do() {
281 _g1->set_refine_cte_cl_concurrency(false);
282 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
283 dcqs.concatenate_logs();
284 }
285
286 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
287 // Cleanup after copy
288 _g1->set_refine_cte_cl_concurrency(true);
289 // Set all cards back to clean.
290 _g1->cleanUpCardTable();
291
292 DirtyCardQueueSet& into_cset_dcqs = _into_cset_dirty_card_queue_set;
293 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
294
295 if (_g1->evacuation_failed()) {
296 double restore_remembered_set_start = os::elapsedTime();
297
298 // Restore remembered sets for the regions pointing into the collection set.
299 // We just need to transfer the completed buffers from the DirtyCardQueueSet
300 // used to hold cards that contain references that point into the collection set
301 // to the DCQS used to hold the deferred RS updates.
302 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
303 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
304 }
305
306 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
307 // which contain references that point into the collection.
308 _into_cset_dirty_card_queue_set.clear();
309 assert(_into_cset_dirty_card_queue_set.completed_buffers_num() == 0,
310 "all buffers should be freed");
311 _into_cset_dirty_card_queue_set.clear_n_completed_buffers();
312 }
313
314 class ScrubRSClosure: public HeapRegionClosure {
315 G1CollectedHeap* _g1h;
316 BitMap* _region_bm;
317 BitMap* _card_bm;
318 CardTableModRefBS* _ctbs;
319 public:
320 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
321 _g1h(G1CollectedHeap::heap()),
322 _region_bm(region_bm), _card_bm(card_bm),
323 _ctbs(_g1h->g1_barrier_set()) {}
324
325 bool doHeapRegion(HeapRegion* r) {
326 if (!r->is_continues_humongous()) {
327 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
328 }
329 return false;
330 }
331 };
332
333 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
334 ScrubRSClosure scrub_cl(region_bm, card_bm);
335 _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
336 }
337
338 G1TriggerClosure::G1TriggerClosure() :
339 _triggered(false) { }
340
341 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
342 OopClosure* oop_cl) :
343 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
344
345 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
346 _c1(c1), _c2(c2) { }
347
348 G1UpdateRSOrPushRefOopClosure::
349 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
350 G1RemSet* rs,
351 G1ParPushHeapRSClosure* push_ref_cl,
352 bool record_refs_into_cset,
353 uint worker_i) :
354 _g1(g1h), _g1_rem_set(rs), _from(NULL),
355 _record_refs_into_cset(record_refs_into_cset),
356 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
357
358 // Returns true if the given card contains references that point
359 // into the collection set, if we're checking for such references;
360 // false otherwise.
361
362 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
363 bool check_for_refs_into_cset) {
364 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
365 "Card at " PTR_FORMAT " index " SIZE_FORMAT " representing heap at " PTR_FORMAT " (%u) must be in committed heap",
366 p2i(card_ptr),
367 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
368 p2i(_ct_bs->addr_for(card_ptr)),
369 _g1->addr_to_region(_ct_bs->addr_for(card_ptr)));
370
371 // If the card is no longer dirty, nothing to do.
372 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
373 // No need to return that this card contains refs that point
374 // into the collection set.
375 return false;
376 }
377
378 // Construct the region representing the card.
379 HeapWord* start = _ct_bs->addr_for(card_ptr);
380 // And find the region containing it.
381 HeapRegion* r = _g1->heap_region_containing(start);
382
383 // Why do we have to check here whether a card is on a young region,
384 // given that we dirty young regions and, as a result, the
385 // post-barrier is supposed to filter them out and never to enqueue
386 // them? When we allocate a new region as the "allocation region" we
387 // actually dirty its cards after we release the lock, since card
388 // dirtying while holding the lock was a performance bottleneck. So,
389 // as a result, it is possible for other threads to actually
390 // allocate objects in the region (after the acquire the lock)
391 // before all the cards on the region are dirtied. This is unlikely,
392 // and it doesn't happen often, but it can happen. So, the extra
393 // check below filters out those cards.
394 if (r->is_young()) {
395 return false;
396 }
397
398 // While we are processing RSet buffers during the collection, we
399 // actually don't want to scan any cards on the collection set,
400 // since we don't want to update remembered sets with entries that
401 // point into the collection set, given that live objects from the
402 // collection set are about to move and such entries will be stale
403 // very soon. This change also deals with a reliability issue which
404 // involves scanning a card in the collection set and coming across
405 // an array that was being chunked and looking malformed. Note,
406 // however, that if evacuation fails, we have to scan any objects
407 // that were not moved and create any missing entries.
408 if (r->in_collection_set()) {
409 return false;
410 }
411
412 // The result from the hot card cache insert call is either:
413 // * pointer to the current card
414 // (implying that the current card is not 'hot'),
415 // * null
416 // (meaning we had inserted the card ptr into the "hot" card cache,
417 // which had some headroom),
418 // * a pointer to a "hot" card that was evicted from the "hot" cache.
419 //
420
421 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
422 if (hot_card_cache->use_cache()) {
423 assert(!check_for_refs_into_cset, "sanity");
424 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
425
426 card_ptr = hot_card_cache->insert(card_ptr);
427 if (card_ptr == NULL) {
428 // There was no eviction. Nothing to do.
429 return false;
430 }
431
432 start = _ct_bs->addr_for(card_ptr);
433 r = _g1->heap_region_containing(start);
434
435 // Checking whether the region we got back from the cache
436 // is young here is inappropriate. The region could have been
437 // freed, reallocated and tagged as young while in the cache.
438 // Hence we could see its young type change at any time.
439 }
440
441 // Don't use addr_for(card_ptr + 1) which can ask for
442 // a card beyond the heap. This is not safe without a perm
443 // gen at the upper end of the heap.
444 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
445 MemRegion dirtyRegion(start, end);
446
447 G1ParPushHeapRSClosure* oops_in_heap_closure = NULL;
448 if (check_for_refs_into_cset) {
449 // ConcurrentG1RefineThreads have worker numbers larger than what
450 // _cset_rs_update_cl[] is set up to handle. But those threads should
451 // only be active outside of a collection which means that when they
452 // reach here they should have check_for_refs_into_cset == false.
453 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
454 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
455 }
456 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
457 _g1->g1_rem_set(),
458 oops_in_heap_closure,
459 check_for_refs_into_cset,
460 worker_i);
461 update_rs_oop_cl.set_from(r);
462
463 G1TriggerClosure trigger_cl;
464 FilterIntoCSClosure into_cs_cl(_g1, &trigger_cl);
465 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
466 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
467
468 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
469 (check_for_refs_into_cset ?
470 (OopClosure*)&mux :
471 (OopClosure*)&update_rs_oop_cl));
472
473 // The region for the current card may be a young region. The
474 // current card may have been a card that was evicted from the
475 // card cache. When the card was inserted into the cache, we had
476 // determined that its region was non-young. While in the cache,
477 // the region may have been freed during a cleanup pause, reallocated
478 // and tagged as young.
479 //
480 // We wish to filter out cards for such a region but the current
481 // thread, if we're running concurrently, may "see" the young type
482 // change at any time (so an earlier "is_young" check may pass or
483 // fail arbitrarily). We tell the iteration code to perform this
484 // filtering when it has been determined that there has been an actual
485 // allocation in this region and making it safe to check the young type.
486 bool filter_young = true;
487
488 HeapWord* stop_point =
489 r->oops_on_card_seq_iterate_careful(dirtyRegion,
490 &filter_then_update_rs_oop_cl,
491 filter_young,
492 card_ptr);
493
494 // If stop_point is non-null, then we encountered an unallocated region
495 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
496 // card and re-enqueue: if we put off the card until a GC pause, then the
497 // unallocated portion will be filled in. Alternatively, we might try
498 // the full complexity of the technique used in "regular" precleaning.
499 if (stop_point != NULL) {
500 // The card might have gotten re-dirtied and re-enqueued while we
501 // worked. (In fact, it's pretty likely.)
502 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
503 *card_ptr = CardTableModRefBS::dirty_card_val();
504 MutexLockerEx x(Shared_DirtyCardQ_lock,
505 Mutex::_no_safepoint_check_flag);
506 DirtyCardQueue* sdcq =
507 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
508 sdcq->enqueue(card_ptr);
509 }
510 } else {
511 _conc_refine_cards++;
512 }
513
514 // This gets set to true if the card being refined has
515 // references that point into the collection set.
516 bool has_refs_into_cset = trigger_cl.triggered();
517
518 // We should only be detecting that the card contains references
519 // that point into the collection set if the current thread is
520 // a GC worker thread.
521 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
522 "invalid result at non safepoint");
523
524 return has_refs_into_cset;
525 }
526
527 void G1RemSet::print_periodic_summary_info(const char* header, uint period_count) {
528 if ((G1SummarizeRSetStatsPeriod > 0) && log_is_enabled(Trace, gc, remset) &&
529 (period_count % G1SummarizeRSetStatsPeriod == 0)) {
530
531 if (!_prev_period_summary.initialized()) {
532 _prev_period_summary.initialize(this);
533 }
534
535 G1RemSetSummary current;
536 current.initialize(this);
537 _prev_period_summary.subtract_from(¤t);
538
539 LogHandle(gc, remset) log;
540 log.trace("%s", header);
541 ResourceMark rm;
542 _prev_period_summary.print_on(log.trace_stream());
543
544 _prev_period_summary.set(¤t);
545 }
546 }
547
548 void G1RemSet::print_summary_info() {
549 LogHandle(gc, remset, exit) log;
550 if (log.is_trace()) {
551 log.trace(" Cumulative RS summary");
552 G1RemSetSummary current;
553 current.initialize(this);
554 ResourceMark rm;
555 current.print_on(log.trace_stream());
556 }
557 }
558
559 void G1RemSet::prepare_for_verify() {
560 if (G1HRRSFlushLogBuffersOnVerify &&
561 (VerifyBeforeGC || VerifyAfterGC)
562 && (!_g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC)) {
563 cleanupHRRS();
564 _g1->set_refine_cte_cl_concurrency(false);
565 if (SafepointSynchronize::is_at_safepoint()) {
566 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
567 dcqs.concatenate_logs();
568 }
569
570 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
571 bool use_hot_card_cache = hot_card_cache->use_cache();
572 hot_card_cache->set_use_cache(false);
573
574 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set);
575 updateRS(&into_cset_dcq, 0);
576 _into_cset_dirty_card_queue_set.clear();
577
578 hot_card_cache->set_use_cache(use_hot_card_cache);
579 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
580 }
581 }