1 /*
2 * Copyright (c) 2001, 2014, 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_implementation/g1/concurrentG1Refine.hpp"
27 #include "gc_implementation/g1/concurrentG1RefineThread.hpp"
28 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
31 #include "gc_implementation/g1/g1HotCardCache.hpp"
32 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
33 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
34 #include "gc_implementation/g1/g1RemSet.inline.hpp"
35 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
36 #include "gc_implementation/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
42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43
44 #define CARD_REPEAT_HISTO 0
45
46 #if CARD_REPEAT_HISTO
47 static size_t ct_freq_sz;
48 static jbyte* ct_freq = NULL;
49
50 void init_ct_freq_table(size_t heap_sz_bytes) {
51 if (ct_freq == NULL) {
52 ct_freq_sz = heap_sz_bytes/CardTableModRefBS::card_size;
53 ct_freq = new jbyte[ct_freq_sz];
54 for (size_t j = 0; j < ct_freq_sz; j++) ct_freq[j] = 0;
55 }
56 }
57
58 void ct_freq_note_card(size_t index) {
59 assert(0 <= index && index < ct_freq_sz, "Bounds error.");
60 if (ct_freq[index] < 100) { ct_freq[index]++; }
61 }
62
63 static IntHistogram card_repeat_count(10, 10);
64
65 void ct_freq_update_histo_and_reset() {
66 for (size_t j = 0; j < ct_freq_sz; j++) {
67 card_repeat_count.add_entry(ct_freq[j]);
68 ct_freq[j] = 0;
69 }
70
71 }
72 #endif
73
74 G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
75 : _g1(g1), _conc_refine_cards(0),
76 _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
77 _cg1r(g1->concurrent_g1_refine()),
78 _cset_rs_update_cl(NULL),
79 _cards_scanned(NULL), _total_cards_scanned(0),
80 _prev_period_summary()
81 {
82 _seq_task = new SubTasksDone(NumSeqTasks);
83 guarantee(n_workers() > 0, "There should be some workers");
84 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(OopsInHeapRegionClosure*, n_workers(), mtGC);
85 for (uint i = 0; i < n_workers(); i++) {
86 _cset_rs_update_cl[i] = NULL;
87 }
88 if (G1SummarizeRSetStats) {
89 _prev_period_summary.initialize(this);
90 }
91 }
92
93 G1RemSet::~G1RemSet() {
94 delete _seq_task;
95 for (uint i = 0; i < n_workers(); i++) {
96 assert(_cset_rs_update_cl[i] == NULL, "it should be");
97 }
98 FREE_C_HEAP_ARRAY(OopsInHeapRegionClosure*, _cset_rs_update_cl, mtGC);
99 }
100
101 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
102 if (_g1->is_in_g1_reserved(mr.start())) {
103 _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size));
104 if (_start_first == NULL) _start_first = mr.start();
105 }
106 }
107
108 class ScanRSClosure : public HeapRegionClosure {
109 size_t _cards_done, _cards;
110 G1CollectedHeap* _g1h;
111
112 OopsInHeapRegionClosure* _oc;
113 CodeBlobClosure* _code_root_cl;
114
115 G1BlockOffsetSharedArray* _bot_shared;
116 G1SATBCardTableModRefBS *_ct_bs;
117
118 double _strong_code_root_scan_time_sec;
119 uint _worker_i;
120 int _block_size;
121 bool _try_claimed;
122
123 public:
124 ScanRSClosure(OopsInHeapRegionClosure* oc,
125 CodeBlobClosure* code_root_cl,
126 uint worker_i) :
127 _oc(oc),
128 _code_root_cl(code_root_cl),
129 _strong_code_root_scan_time_sec(0.0),
130 _cards(0),
131 _cards_done(0),
132 _worker_i(worker_i),
133 _try_claimed(false)
134 {
135 _g1h = G1CollectedHeap::heap();
136 _bot_shared = _g1h->bot_shared();
137 _ct_bs = _g1h->g1_barrier_set();
138 _block_size = MAX2<int>(G1RSetScanBlockSize, 1);
139 }
140
141 void set_try_claimed() { _try_claimed = true; }
142
143 void scanCard(size_t index, HeapRegion *r) {
144 // Stack allocate the DirtyCardToOopClosure instance
145 HeapRegionDCTOC cl(_g1h, r, _oc,
146 CardTableModRefBS::Precise,
147 HeapRegionDCTOC::IntoCSFilterKind);
148
149 // Set the "from" region in the closure.
150 _oc->set_region(r);
151 HeapWord* card_start = _bot_shared->address_for_index(index);
152 HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words;
153 Space *sp = SharedHeap::heap()->space_containing(card_start);
154 MemRegion sm_region = sp->used_region_at_save_marks();
155 MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end));
156 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
157 // We make the card as "claimed" lazily (so races are possible
158 // but they're benign), which reduces the number of duplicate
159 // scans (the rsets of the regions in the cset can intersect).
160 _ct_bs->set_card_claimed(index);
161 _cards_done++;
162 cl.do_MemRegion(mr);
163 }
164 }
165
166 void printCard(HeapRegion* card_region, size_t card_index,
167 HeapWord* card_start) {
168 gclog_or_tty->print_cr("T %u Region [" PTR_FORMAT ", " PTR_FORMAT ") "
169 "RS names card " SIZE_FORMAT_HEX ": "
170 "[" PTR_FORMAT ", " PTR_FORMAT ")",
171 _worker_i,
172 card_region->bottom(), card_region->end(),
173 card_index,
174 card_start, card_start + G1BlockOffsetSharedArray::N_words);
175 }
176
177 void scan_strong_code_roots(HeapRegion* r) {
178 double scan_start = os::elapsedTime();
179 r->strong_code_roots_do(_code_root_cl);
180 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
181 }
182
183 bool doHeapRegion(HeapRegion* r) {
184 assert(r->in_collection_set(), "should only be called on elements of CS.");
185 HeapRegionRemSet* hrrs = r->rem_set();
186 if (hrrs->iter_is_complete()) return false; // All done.
187 if (!_try_claimed && !hrrs->claim_iter()) return false;
188 // If we ever free the collection set concurrently, we should also
189 // clear the card table concurrently therefore we won't need to
190 // add regions of the collection set to the dirty cards region.
191 _g1h->push_dirty_cards_region(r);
192 // If we didn't return above, then
193 // _try_claimed || r->claim_iter()
194 // is true: either we're supposed to work on claimed-but-not-complete
195 // regions, or we successfully claimed the region.
196
197 HeapRegionRemSetIterator iter(hrrs);
198 size_t card_index;
199
200 // We claim cards in block so as to reduce the contention. The block size is determined by
201 // the G1RSetScanBlockSize parameter.
202 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
203 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
204 if (current_card >= jump_to_card + _block_size) {
205 jump_to_card = hrrs->iter_claimed_next(_block_size);
206 }
207 if (current_card < jump_to_card) continue;
208 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
209 #if 0
210 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
211 card_start, card_start + CardTableModRefBS::card_size_in_words);
212 #endif
213
214 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
215 _cards++;
216
217 if (!card_region->is_on_dirty_cards_region_list()) {
218 _g1h->push_dirty_cards_region(card_region);
219 }
220
221 // If the card is dirty, then we will scan it during updateRS.
222 if (!card_region->in_collection_set() &&
223 !_ct_bs->is_card_dirty(card_index)) {
224 scanCard(card_index, card_region);
225 }
226 }
227 if (!_try_claimed) {
228 // Scan the strong code root list attached to the current region
229 scan_strong_code_roots(r);
230
231 hrrs->set_iter_complete();
232 }
233 return false;
234 }
235
236 double strong_code_root_scan_time_sec() {
237 return _strong_code_root_scan_time_sec;
238 }
239
240 size_t cards_done() { return _cards_done;}
241 size_t cards_looked_up() { return _cards;}
242 };
243
244 void G1RemSet::scanRS(OopsInHeapRegionClosure* oc,
245 CodeBlobClosure* code_root_cl,
246 uint worker_i) {
247 double rs_time_start = os::elapsedTime();
248 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
249
250 ScanRSClosure scanRScl(oc, code_root_cl, worker_i);
251
252 _g1->collection_set_iterate_from(startRegion, &scanRScl);
253 scanRScl.set_try_claimed();
254 _g1->collection_set_iterate_from(startRegion, &scanRScl);
255
256 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
257 - scanRScl.strong_code_root_scan_time_sec();
258
259 assert(_cards_scanned != NULL, "invariant");
260 _cards_scanned[worker_i] = scanRScl.cards_done();
261
262 _g1p->phase_times()->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
263 _g1p->phase_times()->record_strong_code_root_scan_time(worker_i,
264 scanRScl.strong_code_root_scan_time_sec() * 1000.0);
265 }
266
267 // Closure used for updating RSets and recording references that
268 // point into the collection set. Only called during an
269 // evacuation pause.
270
271 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
272 G1RemSet* _g1rs;
273 DirtyCardQueue* _into_cset_dcq;
274 public:
275 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
276 DirtyCardQueue* into_cset_dcq) :
277 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
278 {}
279 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
280 // The only time we care about recording cards that
281 // contain references that point into the collection set
282 // is during RSet updating within an evacuation pause.
283 // In this case worker_i should be the id of a GC worker thread.
284 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
285 assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), "should be a GC worker");
286
287 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
288 // 'card_ptr' contains references that point into the collection
289 // set. We need to record the card in the DCQS
290 // (G1CollectedHeap::into_cset_dirty_card_queue_set())
291 // that's used for that purpose.
292 //
293 // Enqueue the card
294 _into_cset_dcq->enqueue(card_ptr);
295 }
296 return true;
297 }
298 };
299
300 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
301 double start = os::elapsedTime();
302 // Apply the given closure to all remaining log entries.
303 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
304
305 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i);
306
307 // Now there should be no dirty cards.
308 if (G1RSLogCheckCardTable) {
309 CountNonCleanMemRegionClosure cl(_g1);
310 _ct_bs->mod_card_iterate(&cl);
311 // XXX This isn't true any more: keeping cards of young regions
312 // marked dirty broke it. Need some reasonable fix.
313 guarantee(cl.n() == 0, "Card table should be clean.");
314 }
315
316 _g1p->phase_times()->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
317 }
318
319 void G1RemSet::cleanupHRRS() {
320 HeapRegionRemSet::cleanup();
321 }
322
323 void G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
324 CodeBlobClosure* code_root_cl,
325 uint worker_i) {
326 #if CARD_REPEAT_HISTO
327 ct_freq_update_histo_and_reset();
328 #endif
329
330 // We cache the value of 'oc' closure into the appropriate slot in the
331 // _cset_rs_update_cl for this worker
332 assert(worker_i < n_workers(), "sanity");
333 _cset_rs_update_cl[worker_i] = oc;
334
335 // A DirtyCardQueue that is used to hold cards containing references
336 // that point into the collection set. This DCQ is associated with a
337 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
338 // circumstances (i.e. the pause successfully completes), these cards
339 // are just discarded (there's no need to update the RSets of regions
340 // that were in the collection set - after the pause these regions
341 // are wholly 'free' of live objects. In the event of an evacuation
342 // failure the cards/buffers in this queue set are passed to the
343 // DirtyCardQueueSet that is used to manage RSet updates
344 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
345
346 assert((ParallelGCThreads > 0) || worker_i == 0, "invariant");
347
348 updateRS(&into_cset_dcq, worker_i);
349 scanRS(oc, code_root_cl, worker_i);
350
351 // We now clear the cached values of _cset_rs_update_cl for this worker
352 _cset_rs_update_cl[worker_i] = NULL;
353 }
354
355 void G1RemSet::prepare_for_oops_into_collection_set_do() {
356 cleanupHRRS();
357 _g1->set_refine_cte_cl_concurrency(false);
358 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
359 dcqs.concatenate_logs();
360
361 guarantee( _cards_scanned == NULL, "invariant" );
362 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers(), mtGC);
363 for (uint i = 0; i < n_workers(); ++i) {
364 _cards_scanned[i] = 0;
365 }
366 _total_cards_scanned = 0;
367 }
368
369 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
370 guarantee( _cards_scanned != NULL, "invariant" );
371 _total_cards_scanned = 0;
372 for (uint i = 0; i < n_workers(); ++i) {
373 _total_cards_scanned += _cards_scanned[i];
374 }
375 FREE_C_HEAP_ARRAY(size_t, _cards_scanned, mtGC);
376 _cards_scanned = NULL;
377 // Cleanup after copy
378 _g1->set_refine_cte_cl_concurrency(true);
379 // Set all cards back to clean.
380 _g1->cleanUpCardTable();
381
382 DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
383 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
384
385 if (_g1->evacuation_failed()) {
386 double restore_remembered_set_start = os::elapsedTime();
387
388 // Restore remembered sets for the regions pointing into the collection set.
389 // We just need to transfer the completed buffers from the DirtyCardQueueSet
390 // used to hold cards that contain references that point into the collection set
391 // to the DCQS used to hold the deferred RS updates.
392 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
393 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
394 }
395
396 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
397 // which contain references that point into the collection.
398 _g1->into_cset_dirty_card_queue_set().clear();
399 assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
400 "all buffers should be freed");
401 _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
402 }
403
404 class ScrubRSClosure: public HeapRegionClosure {
405 G1CollectedHeap* _g1h;
406 BitMap* _region_bm;
407 BitMap* _card_bm;
408 CardTableModRefBS* _ctbs;
409 public:
410 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
411 _g1h(G1CollectedHeap::heap()),
412 _region_bm(region_bm), _card_bm(card_bm),
413 _ctbs(_g1h->g1_barrier_set()) {}
414
415 bool doHeapRegion(HeapRegion* r) {
416 if (!r->is_continues_humongous()) {
417 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
418 }
419 return false;
420 }
421 };
422
423 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
424 ScrubRSClosure scrub_cl(region_bm, card_bm);
425 _g1->heap_region_iterate(&scrub_cl);
426 }
427
428 void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
429 ScrubRSClosure scrub_cl(region_bm, card_bm);
430 _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
431 }
432
433 G1TriggerClosure::G1TriggerClosure() :
434 _triggered(false) { }
435
436 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
437 OopClosure* oop_cl) :
438 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
439
440 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
441 _c1(c1), _c2(c2) { }
442
443 G1UpdateRSOrPushRefOopClosure::
444 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
445 G1RemSet* rs,
446 OopsInHeapRegionClosure* push_ref_cl,
447 bool record_refs_into_cset,
448 uint worker_i) :
449 _g1(g1h), _g1_rem_set(rs), _from(NULL),
450 _record_refs_into_cset(record_refs_into_cset),
451 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
452
453 // Returns true if the given card contains references that point
454 // into the collection set, if we're checking for such references;
455 // false otherwise.
456
457 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
458 bool check_for_refs_into_cset) {
459 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
460 err_msg("Card at "PTR_FORMAT" index "SIZE_FORMAT" representing heap at "PTR_FORMAT" (%u) must be in committed heap",
461 p2i(card_ptr),
462 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
463 _ct_bs->addr_for(card_ptr),
464 _g1->addr_to_region(_ct_bs->addr_for(card_ptr))));
465
466 // If the card is no longer dirty, nothing to do.
467 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
468 // No need to return that this card contains refs that point
469 // into the collection set.
470 return false;
471 }
472
473 // Construct the region representing the card.
474 HeapWord* start = _ct_bs->addr_for(card_ptr);
475 // And find the region containing it.
476 HeapRegion* r = _g1->heap_region_containing(start);
477
478 // Why do we have to check here whether a card is on a young region,
479 // given that we dirty young regions and, as a result, the
480 // post-barrier is supposed to filter them out and never to enqueue
481 // them? When we allocate a new region as the "allocation region" we
482 // actually dirty its cards after we release the lock, since card
483 // dirtying while holding the lock was a performance bottleneck. So,
484 // as a result, it is possible for other threads to actually
485 // allocate objects in the region (after the acquire the lock)
486 // before all the cards on the region are dirtied. This is unlikely,
487 // and it doesn't happen often, but it can happen. So, the extra
488 // check below filters out those cards.
489 if (r->is_young()) {
490 return false;
491 }
492
493 // While we are processing RSet buffers during the collection, we
494 // actually don't want to scan any cards on the collection set,
495 // since we don't want to update remembered sets with entries that
496 // point into the collection set, given that live objects from the
497 // collection set are about to move and such entries will be stale
498 // very soon. This change also deals with a reliability issue which
499 // involves scanning a card in the collection set and coming across
500 // an array that was being chunked and looking malformed. Note,
501 // however, that if evacuation fails, we have to scan any objects
502 // that were not moved and create any missing entries.
503 if (r->in_collection_set()) {
504 return false;
505 }
506
507 // The result from the hot card cache insert call is either:
508 // * pointer to the current card
509 // (implying that the current card is not 'hot'),
510 // * null
511 // (meaning we had inserted the card ptr into the "hot" card cache,
512 // which had some headroom),
513 // * a pointer to a "hot" card that was evicted from the "hot" cache.
514 //
515
516 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
517 if (hot_card_cache->use_cache()) {
518 assert(!check_for_refs_into_cset, "sanity");
519 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
520
521 card_ptr = hot_card_cache->insert(card_ptr);
522 if (card_ptr == NULL) {
523 // There was no eviction. Nothing to do.
524 return false;
525 }
526
527 start = _ct_bs->addr_for(card_ptr);
528 r = _g1->heap_region_containing(start);
529
530 // Checking whether the region we got back from the cache
531 // is young here is inappropriate. The region could have been
532 // freed, reallocated and tagged as young while in the cache.
533 // Hence we could see its young type change at any time.
534 }
535
536 // Don't use addr_for(card_ptr + 1) which can ask for
537 // a card beyond the heap. This is not safe without a perm
538 // gen at the upper end of the heap.
539 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
540 MemRegion dirtyRegion(start, end);
541
542 #if CARD_REPEAT_HISTO
543 init_ct_freq_table(_g1->max_capacity());
544 ct_freq_note_card(_ct_bs->index_for(start));
545 #endif
546
547 OopsInHeapRegionClosure* oops_in_heap_closure = NULL;
548 if (check_for_refs_into_cset) {
549 // ConcurrentG1RefineThreads have worker numbers larger than what
550 // _cset_rs_update_cl[] is set up to handle. But those threads should
551 // only be active outside of a collection which means that when they
552 // reach here they should have check_for_refs_into_cset == false.
553 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
554 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
555 }
556 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
557 _g1->g1_rem_set(),
558 oops_in_heap_closure,
559 check_for_refs_into_cset,
560 worker_i);
561 update_rs_oop_cl.set_from(r);
562
563 G1TriggerClosure trigger_cl;
564 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
565 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
566 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
567
568 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
569 (check_for_refs_into_cset ?
570 (OopClosure*)&mux :
571 (OopClosure*)&update_rs_oop_cl));
572
573 // The region for the current card may be a young region. The
574 // current card may have been a card that was evicted from the
575 // card cache. When the card was inserted into the cache, we had
576 // determined that its region was non-young. While in the cache,
577 // the region may have been freed during a cleanup pause, reallocated
578 // and tagged as young.
579 //
580 // We wish to filter out cards for such a region but the current
581 // thread, if we're running concurrently, may "see" the young type
582 // change at any time (so an earlier "is_young" check may pass or
583 // fail arbitrarily). We tell the iteration code to perform this
584 // filtering when it has been determined that there has been an actual
585 // allocation in this region and making it safe to check the young type.
586 bool filter_young = true;
587
588 HeapWord* stop_point =
589 r->oops_on_card_seq_iterate_careful(dirtyRegion,
590 &filter_then_update_rs_oop_cl,
591 filter_young,
592 card_ptr);
593
594 // If stop_point is non-null, then we encountered an unallocated region
595 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
596 // card and re-enqueue: if we put off the card until a GC pause, then the
597 // unallocated portion will be filled in. Alternatively, we might try
598 // the full complexity of the technique used in "regular" precleaning.
599 if (stop_point != NULL) {
600 // The card might have gotten re-dirtied and re-enqueued while we
601 // worked. (In fact, it's pretty likely.)
602 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
603 *card_ptr = CardTableModRefBS::dirty_card_val();
604 MutexLockerEx x(Shared_DirtyCardQ_lock,
605 Mutex::_no_safepoint_check_flag);
606 DirtyCardQueue* sdcq =
607 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
608 sdcq->enqueue(card_ptr);
609 }
610 } else {
611 _conc_refine_cards++;
612 }
613
614 // This gets set to true if the card being refined has
615 // references that point into the collection set.
616 bool has_refs_into_cset = trigger_cl.triggered();
617
618 // We should only be detecting that the card contains references
619 // that point into the collection set if the current thread is
620 // a GC worker thread.
621 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
622 "invalid result at non safepoint");
623
624 return has_refs_into_cset;
625 }
626
627 void G1RemSet::print_periodic_summary_info(const char* header) {
628 G1RemSetSummary current;
629 current.initialize(this);
630
631 _prev_period_summary.subtract_from(¤t);
632 print_summary_info(&_prev_period_summary, header);
633
634 _prev_period_summary.set(¤t);
635 }
636
637 void G1RemSet::print_summary_info() {
638 G1RemSetSummary current;
639 current.initialize(this);
640
641 print_summary_info(¤t, " Cumulative RS summary");
642 }
643
644 void G1RemSet::print_summary_info(G1RemSetSummary * summary, const char * header) {
645 assert(summary != NULL, "just checking");
646
647 if (header != NULL) {
648 gclog_or_tty->print_cr("%s", header);
649 }
650
651 #if CARD_REPEAT_HISTO
652 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
653 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
654 card_repeat_count.print_on(gclog_or_tty);
655 #endif
656
657 summary->print_on(gclog_or_tty);
658 }
659
660 void G1RemSet::prepare_for_verify() {
661 if (G1HRRSFlushLogBuffersOnVerify &&
662 (VerifyBeforeGC || VerifyAfterGC)
663 && (!_g1->full_collection() || G1VerifyRSetsDuringFullGC)) {
664 cleanupHRRS();
665 _g1->set_refine_cte_cl_concurrency(false);
666 if (SafepointSynchronize::is_at_safepoint()) {
667 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
668 dcqs.concatenate_logs();
669 }
670
671 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
672 bool use_hot_card_cache = hot_card_cache->use_cache();
673 hot_card_cache->set_use_cache(false);
674
675 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
676 updateRS(&into_cset_dcq, 0);
677 _g1->into_cset_dirty_card_queue_set().clear();
678
679 hot_card_cache->set_use_cache(use_hot_card_cache);
680 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
681 }
682 }