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 _into_cset_dirty_card_queue_set(false)
50 {
51 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, n_workers(), mtGC);
52 for (uint i = 0; i < n_workers(); i++) {
53 _cset_rs_update_cl[i] = NULL;
54 }
55 if (log_is_enabled(Trace, gc, remset)) {
56 _prev_period_summary.initialize(this);
57 }
58 // Initialize the card queue set used to hold cards containing
59 // references into the collection set.
60 _into_cset_dirty_card_queue_set.initialize(NULL, // Should never be called by the Java code
61 DirtyCardQ_CBL_mon,
62 DirtyCardQ_FL_lock,
63 -1, // never trigger processing
64 -1, // no limit on length
65 Shared_DirtyCardQ_lock,
66 &JavaThread::dirty_card_queue_set());
67 }
68
69 G1RemSet::~G1RemSet() {
70 for (uint i = 0; i < n_workers(); i++) {
71 assert(_cset_rs_update_cl[i] == NULL, "it should be");
72 }
73 FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl);
74 }
75
76 class ScanRSClosure : public HeapRegionClosure {
77 size_t _cards_done, _cards;
78 G1CollectedHeap* _g1h;
79
80 G1ParPushHeapRSClosure* _oc;
81 CodeBlobClosure* _code_root_cl;
82
83 G1BlockOffsetSharedArray* _bot_shared;
84 G1SATBCardTableModRefBS *_ct_bs;
85
86 double _strong_code_root_scan_time_sec;
87 uint _worker_i;
88 size_t _block_size;
89 bool _try_claimed;
90
91 public:
92 ScanRSClosure(G1ParPushHeapRSClosure* oc,
93 CodeBlobClosure* code_root_cl,
94 uint worker_i) :
95 _oc(oc),
96 _code_root_cl(code_root_cl),
97 _strong_code_root_scan_time_sec(0.0),
98 _cards(0),
99 _cards_done(0),
100 _worker_i(worker_i),
101 _try_claimed(false)
102 {
103 _g1h = G1CollectedHeap::heap();
104 _bot_shared = _g1h->bot_shared();
105 _ct_bs = _g1h->g1_barrier_set();
106 _block_size = MAX2<size_t>(G1RSetScanBlockSize, 1);
107 }
108
109 void set_try_claimed() { _try_claimed = true; }
110
111 void scanCard(size_t index, HeapRegion *r) {
112 // Stack allocate the DirtyCardToOopClosure instance
113 HeapRegionDCTOC cl(_g1h, r, _oc,
114 CardTableModRefBS::Precise);
115
116 // Set the "from" region in the closure.
117 _oc->set_region(r);
118 MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words);
119 MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
120 MemRegion mr = pre_gc_allocated.intersection(card_region);
121 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
122 // We make the card as "claimed" lazily (so races are possible
123 // but they're benign), which reduces the number of duplicate
124 // scans (the rsets of the regions in the cset can intersect).
125 _ct_bs->set_card_claimed(index);
126 _cards_done++;
127 cl.do_MemRegion(mr);
128 }
129 }
130
131 void scan_strong_code_roots(HeapRegion* r) {
132 double scan_start = os::elapsedTime();
133 r->strong_code_roots_do(_code_root_cl);
134 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
135 }
136
137 bool doHeapRegion(HeapRegion* r) {
138 assert(r->in_collection_set(), "should only be called on elements of CS.");
139 HeapRegionRemSet* hrrs = r->rem_set();
140 if (hrrs->iter_is_complete()) return false; // All done.
141 if (!_try_claimed && !hrrs->claim_iter()) return false;
142 // If we ever free the collection set concurrently, we should also
143 // clear the card table concurrently therefore we won't need to
144 // add regions of the collection set to the dirty cards region.
145 _g1h->push_dirty_cards_region(r);
146 // If we didn't return above, then
147 // _try_claimed || r->claim_iter()
148 // is true: either we're supposed to work on claimed-but-not-complete
149 // regions, or we successfully claimed the region.
150
151 HeapRegionRemSetIterator iter(hrrs);
152 size_t card_index;
153
154 // We claim cards in block so as to reduce the contention. The block size is determined by
155 // the G1RSetScanBlockSize parameter.
156 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
157 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
158 if (current_card >= jump_to_card + _block_size) {
159 jump_to_card = hrrs->iter_claimed_next(_block_size);
160 }
161 if (current_card < jump_to_card) continue;
162 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
163 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
164 _cards++;
165
166 if (!card_region->is_on_dirty_cards_region_list()) {
167 _g1h->push_dirty_cards_region(card_region);
168 }
169
170 // If the card is dirty, then we will scan it during updateRS.
171 if (!card_region->in_collection_set() &&
172 !_ct_bs->is_card_dirty(card_index)) {
173 scanCard(card_index, card_region);
174 }
175 }
176 if (!_try_claimed) {
177 // Scan the strong code root list attached to the current region
178 scan_strong_code_roots(r);
179
180 hrrs->set_iter_complete();
181 }
182 return false;
183 }
184
185 double strong_code_root_scan_time_sec() {
186 return _strong_code_root_scan_time_sec;
187 }
188
189 size_t cards_done() { return _cards_done;}
190 size_t cards_looked_up() { return _cards;}
191 };
192
193 size_t G1RemSet::scanRS(G1ParPushHeapRSClosure* oc,
194 CodeBlobClosure* heap_region_codeblobs,
195 uint worker_i) {
196 double rs_time_start = os::elapsedTime();
197
198 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
199
200 ScanRSClosure scanRScl(oc, heap_region_codeblobs, worker_i);
201
202 _g1->collection_set_iterate_from(startRegion, &scanRScl);
203 scanRScl.set_try_claimed();
204 _g1->collection_set_iterate_from(startRegion, &scanRScl);
205
206 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
207 - scanRScl.strong_code_root_scan_time_sec();
208
209 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::ScanRS, worker_i, scan_rs_time_sec);
210 _g1p->phase_times()->record_time_secs(G1GCPhaseTimes::CodeRoots, worker_i, scanRScl.strong_code_root_scan_time_sec());
211
212 return scanRScl.cards_done();
213 }
214
215 // Closure used for updating RSets and recording references that
216 // point into the collection set. Only called during an
217 // evacuation pause.
218
219 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
220 G1RemSet* _g1rs;
221 DirtyCardQueue* _into_cset_dcq;
222 public:
223 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
224 DirtyCardQueue* into_cset_dcq) :
225 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
226 {}
227
228 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
229 // The only time we care about recording cards that
230 // contain references that point into the collection set
231 // is during RSet updating within an evacuation pause.
232 // In this case worker_i should be the id of a GC worker thread.
233 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
234 assert(worker_i < ParallelGCThreads, "should be a GC worker");
235
236 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
237 // 'card_ptr' contains references that point into the collection
238 // set. We need to record the card in the DCQS
239 // (_into_cset_dirty_card_queue_set)
240 // that's used for that purpose.
241 //
242 // Enqueue the card
243 _into_cset_dcq->enqueue(card_ptr);
244 }
245 return true;
246 }
247 };
248
249 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
250 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
251
252 G1GCParPhaseTimesTracker x(_g1p->phase_times(), G1GCPhaseTimes::UpdateRS, worker_i);
253 {
254 // Apply the closure to the entries of the hot card cache.
255 G1GCParPhaseTimesTracker y(_g1p->phase_times(), G1GCPhaseTimes::ScanHCC, worker_i);
256 _g1->iterate_hcc_closure(&into_cset_update_rs_cl, worker_i);
257 }
258 // Apply the closure to all remaining log entries.
259 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, worker_i);
260 }
261
262 void G1RemSet::cleanupHRRS() {
263 HeapRegionRemSet::cleanup();
264 }
265
266 size_t G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc,
267 CodeBlobClosure* heap_region_codeblobs,
268 uint worker_i) {
269 // We cache the value of 'oc' closure into the appropriate slot in the
270 // _cset_rs_update_cl for this worker
271 assert(worker_i < n_workers(), "sanity");
272 _cset_rs_update_cl[worker_i] = oc;
273
274 // A DirtyCardQueue that is used to hold cards containing references
275 // that point into the collection set. This DCQ is associated with a
276 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
277 // circumstances (i.e. the pause successfully completes), these cards
278 // are just discarded (there's no need to update the RSets of regions
279 // that were in the collection set - after the pause these regions
280 // are wholly 'free' of live objects. In the event of an evacuation
281 // failure the cards/buffers in this queue set are passed to the
282 // DirtyCardQueueSet that is used to manage RSet updates
283 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set);
284
285 updateRS(&into_cset_dcq, worker_i);
286 size_t cards_scanned = scanRS(oc, heap_region_codeblobs, worker_i);
287
288 // We now clear the cached values of _cset_rs_update_cl for this worker
289 _cset_rs_update_cl[worker_i] = NULL;
290 return cards_scanned;
291 }
292
293 void G1RemSet::prepare_for_oops_into_collection_set_do() {
294 _g1->set_refine_cte_cl_concurrency(false);
295 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
296 dcqs.concatenate_logs();
297 }
298
299 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
300 // Cleanup after copy
301 _g1->set_refine_cte_cl_concurrency(true);
302 // Set all cards back to clean.
303 _g1->cleanUpCardTable();
304
305 DirtyCardQueueSet& into_cset_dcqs = _into_cset_dirty_card_queue_set;
306 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
307
308 if (_g1->evacuation_failed()) {
309 double restore_remembered_set_start = os::elapsedTime();
310
311 // Restore remembered sets for the regions pointing into the collection set.
312 // We just need to transfer the completed buffers from the DirtyCardQueueSet
313 // used to hold cards that contain references that point into the collection set
314 // to the DCQS used to hold the deferred RS updates.
315 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
316 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
317 }
318
319 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
320 // which contain references that point into the collection.
321 _into_cset_dirty_card_queue_set.clear();
322 assert(_into_cset_dirty_card_queue_set.completed_buffers_num() == 0,
323 "all buffers should be freed");
324 _into_cset_dirty_card_queue_set.clear_n_completed_buffers();
325 }
326
327 class ScrubRSClosure: public HeapRegionClosure {
328 G1CollectedHeap* _g1h;
329 BitMap* _region_bm;
330 BitMap* _card_bm;
331 CardTableModRefBS* _ctbs;
332 public:
333 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
334 _g1h(G1CollectedHeap::heap()),
335 _region_bm(region_bm), _card_bm(card_bm),
336 _ctbs(_g1h->g1_barrier_set()) {}
337
338 bool doHeapRegion(HeapRegion* r) {
339 if (!r->is_continues_humongous()) {
340 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
341 }
342 return false;
343 }
344 };
345
346 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
347 ScrubRSClosure scrub_cl(region_bm, card_bm);
348 _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
349 }
350
351 G1TriggerClosure::G1TriggerClosure() :
352 _triggered(false) { }
353
354 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
355 OopClosure* oop_cl) :
356 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
357
358 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
359 _c1(c1), _c2(c2) { }
360
361 G1UpdateRSOrPushRefOopClosure::
362 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
363 G1RemSet* rs,
364 G1ParPushHeapRSClosure* push_ref_cl,
365 bool record_refs_into_cset,
366 uint worker_i) :
367 _g1(g1h), _g1_rem_set(rs), _from(NULL),
368 _record_refs_into_cset(record_refs_into_cset),
369 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
370
371 // Returns true if the given card contains references that point
372 // into the collection set, if we're checking for such references;
373 // false otherwise.
374
375 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
376 bool check_for_refs_into_cset) {
377 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
378 "Card at " PTR_FORMAT " index " SIZE_FORMAT " representing heap at " PTR_FORMAT " (%u) must be in committed heap",
379 p2i(card_ptr),
380 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
381 p2i(_ct_bs->addr_for(card_ptr)),
382 _g1->addr_to_region(_ct_bs->addr_for(card_ptr)));
383
384 // If the card is no longer dirty, nothing to do.
385 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
386 // No need to return that this card contains refs that point
387 // into the collection set.
388 return false;
389 }
390
391 // Construct the region representing the card.
392 HeapWord* start = _ct_bs->addr_for(card_ptr);
393 // And find the region containing it.
394 HeapRegion* r = _g1->heap_region_containing(start);
395
396 // Why do we have to check here whether a card is on a young region,
397 // given that we dirty young regions and, as a result, the
398 // post-barrier is supposed to filter them out and never to enqueue
399 // them? When we allocate a new region as the "allocation region" we
400 // actually dirty its cards after we release the lock, since card
401 // dirtying while holding the lock was a performance bottleneck. So,
402 // as a result, it is possible for other threads to actually
403 // allocate objects in the region (after the acquire the lock)
404 // before all the cards on the region are dirtied. This is unlikely,
405 // and it doesn't happen often, but it can happen. So, the extra
406 // check below filters out those cards.
407 if (r->is_young()) {
408 return false;
409 }
410
411 // While we are processing RSet buffers during the collection, we
412 // actually don't want to scan any cards on the collection set,
413 // since we don't want to update remembered sets with entries that
414 // point into the collection set, given that live objects from the
415 // collection set are about to move and such entries will be stale
416 // very soon. This change also deals with a reliability issue which
417 // involves scanning a card in the collection set and coming across
418 // an array that was being chunked and looking malformed. Note,
419 // however, that if evacuation fails, we have to scan any objects
420 // that were not moved and create any missing entries.
421 if (r->in_collection_set()) {
422 return false;
423 }
424
425 // The result from the hot card cache insert call is either:
426 // * pointer to the current card
427 // (implying that the current card is not 'hot'),
428 // * null
429 // (meaning we had inserted the card ptr into the "hot" card cache,
430 // which had some headroom),
431 // * a pointer to a "hot" card that was evicted from the "hot" cache.
432 //
433
434 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
435 if (hot_card_cache->use_cache()) {
436 assert(!check_for_refs_into_cset, "sanity");
437 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
438
439 card_ptr = hot_card_cache->insert(card_ptr);
440 if (card_ptr == NULL) {
441 // There was no eviction. Nothing to do.
442 return false;
443 }
444
445 start = _ct_bs->addr_for(card_ptr);
446 r = _g1->heap_region_containing(start);
447
448 // Checking whether the region we got back from the cache
449 // is young here is inappropriate. The region could have been
450 // freed, reallocated and tagged as young while in the cache.
451 // Hence we could see its young type change at any time.
452 }
453
454 // Don't use addr_for(card_ptr + 1) which can ask for
455 // a card beyond the heap. This is not safe without a perm
456 // gen at the upper end of the heap.
457 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
458 MemRegion dirtyRegion(start, end);
459
460 G1ParPushHeapRSClosure* oops_in_heap_closure = NULL;
461 if (check_for_refs_into_cset) {
462 // ConcurrentG1RefineThreads have worker numbers larger than what
463 // _cset_rs_update_cl[] is set up to handle. But those threads should
464 // only be active outside of a collection which means that when they
465 // reach here they should have check_for_refs_into_cset == false.
466 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
467 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
468 }
469 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
470 _g1->g1_rem_set(),
471 oops_in_heap_closure,
472 check_for_refs_into_cset,
473 worker_i);
474 update_rs_oop_cl.set_from(r);
475
476 G1TriggerClosure trigger_cl;
477 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
478 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
479 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
480
481 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
482 (check_for_refs_into_cset ?
483 (OopClosure*)&mux :
484 (OopClosure*)&update_rs_oop_cl));
485
486 // The region for the current card may be a young region. The
487 // current card may have been a card that was evicted from the
488 // card cache. When the card was inserted into the cache, we had
489 // determined that its region was non-young. While in the cache,
490 // the region may have been freed during a cleanup pause, reallocated
491 // and tagged as young.
492 //
493 // We wish to filter out cards for such a region but the current
494 // thread, if we're running concurrently, may "see" the young type
495 // change at any time (so an earlier "is_young" check may pass or
496 // fail arbitrarily). We tell the iteration code to perform this
497 // filtering when it has been determined that there has been an actual
498 // allocation in this region and making it safe to check the young type.
499 bool filter_young = true;
500
501 HeapWord* stop_point =
502 r->oops_on_card_seq_iterate_careful(dirtyRegion,
503 &filter_then_update_rs_oop_cl,
504 filter_young,
505 card_ptr);
506
507 // If stop_point is non-null, then we encountered an unallocated region
508 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
509 // card and re-enqueue: if we put off the card until a GC pause, then the
510 // unallocated portion will be filled in. Alternatively, we might try
511 // the full complexity of the technique used in "regular" precleaning.
512 if (stop_point != NULL) {
513 // The card might have gotten re-dirtied and re-enqueued while we
514 // worked. (In fact, it's pretty likely.)
515 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
516 *card_ptr = CardTableModRefBS::dirty_card_val();
517 MutexLockerEx x(Shared_DirtyCardQ_lock,
518 Mutex::_no_safepoint_check_flag);
519 DirtyCardQueue* sdcq =
520 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
521 sdcq->enqueue(card_ptr);
522 }
523 } else {
524 _conc_refine_cards++;
525 }
526
527 // This gets set to true if the card being refined has
528 // references that point into the collection set.
529 bool has_refs_into_cset = trigger_cl.triggered();
530
531 // We should only be detecting that the card contains references
532 // that point into the collection set if the current thread is
533 // a GC worker thread.
534 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
535 "invalid result at non safepoint");
536
537 return has_refs_into_cset;
538 }
539
540 void G1RemSet::print_periodic_summary_info(const char* header, uint period_count) {
541 if ((G1SummarizeRSetStatsPeriod > 0) && log_is_enabled(Trace, gc, remset) &&
542 (period_count % G1SummarizeRSetStatsPeriod == 0)) {
543
544 if (!_prev_period_summary.initialized()) {
545 _prev_period_summary.initialize(this);
546 }
547
548 G1RemSetSummary current;
549 current.initialize(this);
550 _prev_period_summary.subtract_from(¤t);
551
552 LogHandle(gc, remset) log;
553 log.trace("%s", header);
554 ResourceMark rm;
555 _prev_period_summary.print_on(log.trace_stream());
556
557 _prev_period_summary.set(¤t);
558 }
559 }
560
561 void G1RemSet::print_summary_info() {
562 LogHandle(gc, remset, exit) log;
563 if (log.is_trace()) {
564 log.trace(" Cumulative RS summary");
565 G1RemSetSummary current;
566 current.initialize(this);
567 ResourceMark rm;
568 current.print_on(log.trace_stream());
569 }
570 }
571
572 void G1RemSet::prepare_for_verify() {
573 if (G1HRRSFlushLogBuffersOnVerify &&
574 (VerifyBeforeGC || VerifyAfterGC)
575 && (!_g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC)) {
576 cleanupHRRS();
577 _g1->set_refine_cte_cl_concurrency(false);
578 if (SafepointSynchronize::is_at_safepoint()) {
579 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
580 dcqs.concatenate_logs();
581 }
582
583 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
584 bool use_hot_card_cache = hot_card_cache->use_cache();
585 hot_card_cache->set_use_cache(false);
586
587 DirtyCardQueue into_cset_dcq(&_into_cset_dirty_card_queue_set);
588 updateRS(&into_cset_dcq, 0);
589 _into_cset_dirty_card_queue_set.clear();
590
591 hot_card_cache->set_use_cache(use_hot_card_cache);
592 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
593 }
594 }