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/intHisto.hpp"
40
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 #define CARD_REPEAT_HISTO 0
44
45 #if CARD_REPEAT_HISTO
46 static size_t ct_freq_sz;
47 static jbyte* ct_freq = NULL;
48
49 void init_ct_freq_table(size_t heap_sz_bytes) {
50 if (ct_freq == NULL) {
51 ct_freq_sz = heap_sz_bytes/CardTableModRefBS::card_size;
52 ct_freq = new jbyte[ct_freq_sz];
53 for (size_t j = 0; j < ct_freq_sz; j++) ct_freq[j] = 0;
54 }
55 }
56
57 void ct_freq_note_card(size_t index) {
58 assert(0 <= index && index < ct_freq_sz, "Bounds error.");
59 if (ct_freq[index] < 100) { ct_freq[index]++; }
60 }
61
62 static IntHistogram card_repeat_count(10, 10);
63
64 void ct_freq_update_histo_and_reset() {
65 for (size_t j = 0; j < ct_freq_sz; j++) {
66 card_repeat_count.add_entry(ct_freq[j]);
67 ct_freq[j] = 0;
68 }
69
70 }
71 #endif
72
73 G1RemSet::G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
74 : _g1(g1), _conc_refine_cards(0),
75 _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
76 _cg1r(g1->concurrent_g1_refine()),
77 _cset_rs_update_cl(NULL),
78 _cards_scanned(NULL), _total_cards_scanned(0),
79 _prev_period_summary()
80 {
81 _seq_task = new SubTasksDone(NumSeqTasks);
82 guarantee(n_workers() > 0, "There should be some workers");
83 _cset_rs_update_cl = NEW_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, n_workers(), mtGC);
84 for (uint i = 0; i < n_workers(); i++) {
85 _cset_rs_update_cl[i] = NULL;
86 }
87 if (G1SummarizeRSetStats) {
88 _prev_period_summary.initialize(this);
89 }
90 }
91
92 G1RemSet::~G1RemSet() {
93 delete _seq_task;
94 for (uint i = 0; i < n_workers(); i++) {
95 assert(_cset_rs_update_cl[i] == NULL, "it should be");
96 }
97 FREE_C_HEAP_ARRAY(G1ParPushHeapRSClosure*, _cset_rs_update_cl, mtGC);
98 }
99
100 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
101 if (_g1->is_in_g1_reserved(mr.start())) {
102 _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size));
103 if (_start_first == NULL) _start_first = mr.start();
104 }
105 }
106
107 class ScanRSClosure : public HeapRegionClosure {
108 size_t _cards_done, _cards;
109 G1CollectedHeap* _g1h;
110
111 G1ParPushHeapRSClosure* _oc;
112 CodeBlobClosure* _code_root_cl;
113
114 G1BlockOffsetSharedArray* _bot_shared;
115 G1SATBCardTableModRefBS *_ct_bs;
116
117 double _strong_code_root_scan_time_sec;
118 uint _worker_i;
119 int _block_size;
120 bool _try_claimed;
121
122 public:
123 ScanRSClosure(G1ParPushHeapRSClosure* oc,
124 CodeBlobClosure* code_root_cl,
125 uint worker_i) :
126 _oc(oc),
127 _code_root_cl(code_root_cl),
128 _strong_code_root_scan_time_sec(0.0),
129 _cards(0),
130 _cards_done(0),
131 _worker_i(worker_i),
132 _try_claimed(false)
133 {
134 _g1h = G1CollectedHeap::heap();
135 _bot_shared = _g1h->bot_shared();
136 _ct_bs = _g1h->g1_barrier_set();
137 _block_size = MAX2<int>(G1RSetScanBlockSize, 1);
138 }
139
140 void set_try_claimed() { _try_claimed = true; }
141
142 void scanCard(size_t index, HeapRegion *r) {
143 // Stack allocate the DirtyCardToOopClosure instance
144 HeapRegionDCTOC cl(_g1h, r, _oc,
145 CardTableModRefBS::Precise);
146
147 // Set the "from" region in the closure.
148 _oc->set_region(r);
149 MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words);
150 MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
151 MemRegion mr = pre_gc_allocated.intersection(card_region);
152 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
153 // We make the card as "claimed" lazily (so races are possible
154 // but they're benign), which reduces the number of duplicate
155 // scans (the rsets of the regions in the cset can intersect).
156 _ct_bs->set_card_claimed(index);
157 _cards_done++;
158 cl.do_MemRegion(mr);
159 }
160 }
161
162 void printCard(HeapRegion* card_region, size_t card_index,
163 HeapWord* card_start) {
164 gclog_or_tty->print_cr("T " UINT32_FORMAT " Region [" PTR_FORMAT ", " PTR_FORMAT ") "
165 "RS names card %p: "
166 "[" PTR_FORMAT ", " PTR_FORMAT ")",
167 _worker_i,
168 card_region->bottom(), card_region->end(),
169 card_index,
170 card_start, card_start + G1BlockOffsetSharedArray::N_words);
171 }
172
173 void scan_strong_code_roots(HeapRegion* r) {
174 double scan_start = os::elapsedTime();
175 r->strong_code_roots_do(_code_root_cl);
176 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
177 }
178
179 bool doHeapRegion(HeapRegion* r) {
180 assert(r->in_collection_set(), "should only be called on elements of CS.");
181 HeapRegionRemSet* hrrs = r->rem_set();
182 if (hrrs->iter_is_complete()) return false; // All done.
183 if (!_try_claimed && !hrrs->claim_iter()) return false;
184 // If we ever free the collection set concurrently, we should also
185 // clear the card table concurrently therefore we won't need to
186 // add regions of the collection set to the dirty cards region.
187 _g1h->push_dirty_cards_region(r);
188 // If we didn't return above, then
189 // _try_claimed || r->claim_iter()
190 // is true: either we're supposed to work on claimed-but-not-complete
191 // regions, or we successfully claimed the region.
192
193 HeapRegionRemSetIterator iter(hrrs);
194 size_t card_index;
195
196 // We claim cards in block so as to recude the contention. The block size is determined by
197 // the G1RSetScanBlockSize parameter.
198 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
199 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
200 if (current_card >= jump_to_card + _block_size) {
201 jump_to_card = hrrs->iter_claimed_next(_block_size);
202 }
203 if (current_card < jump_to_card) continue;
204 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
205 #if 0
206 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
207 card_start, card_start + CardTableModRefBS::card_size_in_words);
208 #endif
209
210 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
211 _cards++;
212
213 if (!card_region->is_on_dirty_cards_region_list()) {
214 _g1h->push_dirty_cards_region(card_region);
215 }
216
217 // If the card is dirty, then we will scan it during updateRS.
218 if (!card_region->in_collection_set() &&
219 !_ct_bs->is_card_dirty(card_index)) {
220 scanCard(card_index, card_region);
221 }
222 }
223 if (!_try_claimed) {
224 // Scan the strong code root list attached to the current region
225 scan_strong_code_roots(r);
226
227 hrrs->set_iter_complete();
228 }
229 return false;
230 }
231
232 double strong_code_root_scan_time_sec() {
233 return _strong_code_root_scan_time_sec;
234 }
235
236 size_t cards_done() { return _cards_done;}
237 size_t cards_looked_up() { return _cards;}
238 };
239
240 void G1RemSet::scanRS(G1ParPushHeapRSClosure* oc,
241 CodeBlobClosure* code_root_cl,
242 uint worker_i) {
243 double rs_time_start = os::elapsedTime();
244 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
245
246 ScanRSClosure scanRScl(oc, code_root_cl, worker_i);
247
248 _g1->collection_set_iterate_from(startRegion, &scanRScl);
249 scanRScl.set_try_claimed();
250 _g1->collection_set_iterate_from(startRegion, &scanRScl);
251
252 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
253 - scanRScl.strong_code_root_scan_time_sec();
254
255 assert(_cards_scanned != NULL, "invariant");
256 _cards_scanned[worker_i] = scanRScl.cards_done();
257
258 _g1p->phase_times()->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
259 _g1p->phase_times()->record_strong_code_root_scan_time(worker_i,
260 scanRScl.strong_code_root_scan_time_sec() * 1000.0);
261 }
262
263 // Closure used for updating RSets and recording references that
264 // point into the collection set. Only called during an
265 // evacuation pause.
266
267 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
268 G1RemSet* _g1rs;
269 DirtyCardQueue* _into_cset_dcq;
270 public:
271 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
272 DirtyCardQueue* into_cset_dcq) :
273 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
274 {}
275 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
276 // The only time we care about recording cards that
277 // contain references that point into the collection set
278 // is during RSet updating within an evacuation pause.
279 // In this case worker_i should be the id of a GC worker thread.
280 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
281 assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), "should be a GC worker");
282
283 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
284 // 'card_ptr' contains references that point into the collection
285 // set. We need to record the card in the DCQS
286 // (G1CollectedHeap::into_cset_dirty_card_queue_set())
287 // that's used for that purpose.
288 //
289 // Enqueue the card
290 _into_cset_dcq->enqueue(card_ptr);
291 }
292 return true;
293 }
294 };
295
296 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
297 double start = os::elapsedTime();
298 // Apply the given closure to all remaining log entries.
299 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
300
301 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i);
302
303 // Now there should be no dirty cards.
304 if (G1RSLogCheckCardTable) {
305 CountNonCleanMemRegionClosure cl(_g1);
306 _ct_bs->mod_card_iterate(&cl);
307 // XXX This isn't true any more: keeping cards of young regions
308 // marked dirty broke it. Need some reasonable fix.
309 guarantee(cl.n() == 0, "Card table should be clean.");
310 }
311
312 _g1p->phase_times()->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
313 }
314
315 void G1RemSet::cleanupHRRS() {
316 HeapRegionRemSet::cleanup();
317 }
318
319 void G1RemSet::oops_into_collection_set_do(G1ParPushHeapRSClosure* oc,
320 CodeBlobClosure* code_root_cl,
321 uint worker_i) {
322 #if CARD_REPEAT_HISTO
323 ct_freq_update_histo_and_reset();
324 #endif
325
326 // We cache the value of 'oc' closure into the appropriate slot in the
327 // _cset_rs_update_cl for this worker
328 assert(worker_i < n_workers(), "sanity");
329 _cset_rs_update_cl[worker_i] = oc;
330
331 // A DirtyCardQueue that is used to hold cards containing references
332 // that point into the collection set. This DCQ is associated with a
333 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
334 // circumstances (i.e. the pause successfully completes), these cards
335 // are just discarded (there's no need to update the RSets of regions
336 // that were in the collection set - after the pause these regions
337 // are wholly 'free' of live objects. In the event of an evacuation
338 // failure the cards/buffers in this queue set are passed to the
339 // DirtyCardQueueSet that is used to manage RSet updates
340 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
341
342 assert((ParallelGCThreads > 0) || worker_i == 0, "invariant");
343
344 // The two flags below were introduced temporarily to serialize
345 // the updating and scanning of remembered sets. There are some
346 // race conditions when these two operations are done in parallel
347 // and they are causing failures. When we resolve said race
348 // conditions, we'll revert back to parallel remembered set
349 // updating and scanning. See CRs 6677707 and 6677708.
350 if (G1UseParallelRSetUpdating || (worker_i == 0)) {
351 updateRS(&into_cset_dcq, worker_i);
352 } else {
353 _g1p->phase_times()->record_update_rs_processed_buffers(worker_i, 0);
354 _g1p->phase_times()->record_update_rs_time(worker_i, 0.0);
355 }
356 if (G1UseParallelRSetScanning || (worker_i == 0)) {
357 scanRS(oc, code_root_cl, worker_i);
358 } else {
359 _g1p->phase_times()->record_scan_rs_time(worker_i, 0.0);
360 }
361
362 // We now clear the cached values of _cset_rs_update_cl for this worker
363 _cset_rs_update_cl[worker_i] = NULL;
364 }
365
366 void G1RemSet::prepare_for_oops_into_collection_set_do() {
367 cleanupHRRS();
368 _g1->set_refine_cte_cl_concurrency(false);
369 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
370 dcqs.concatenate_logs();
371
372 guarantee( _cards_scanned == NULL, "invariant" );
373 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers(), mtGC);
374 for (uint i = 0; i < n_workers(); ++i) {
375 _cards_scanned[i] = 0;
376 }
377 _total_cards_scanned = 0;
378 }
379
380 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
381 guarantee( _cards_scanned != NULL, "invariant" );
382 _total_cards_scanned = 0;
383 for (uint i = 0; i < n_workers(); ++i) {
384 _total_cards_scanned += _cards_scanned[i];
385 }
386 FREE_C_HEAP_ARRAY(size_t, _cards_scanned, mtGC);
387 _cards_scanned = NULL;
388 // Cleanup after copy
389 _g1->set_refine_cte_cl_concurrency(true);
390 // Set all cards back to clean.
391 _g1->cleanUpCardTable();
392
393 DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
394 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
395
396 if (_g1->evacuation_failed()) {
397 double restore_remembered_set_start = os::elapsedTime();
398
399 // Restore remembered sets for the regions pointing into the collection set.
400 // We just need to transfer the completed buffers from the DirtyCardQueueSet
401 // used to hold cards that contain references that point into the collection set
402 // to the DCQS used to hold the deferred RS updates.
403 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
404 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
405 }
406
407 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
408 // which contain references that point into the collection.
409 _g1->into_cset_dirty_card_queue_set().clear();
410 assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
411 "all buffers should be freed");
412 _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
413 }
414
415 class ScrubRSClosure: public HeapRegionClosure {
416 G1CollectedHeap* _g1h;
417 BitMap* _region_bm;
418 BitMap* _card_bm;
419 CardTableModRefBS* _ctbs;
420 public:
421 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
422 _g1h(G1CollectedHeap::heap()),
423 _region_bm(region_bm), _card_bm(card_bm),
424 _ctbs(_g1h->g1_barrier_set()) {}
425
426 bool doHeapRegion(HeapRegion* r) {
427 if (!r->continuesHumongous()) {
428 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
429 }
430 return false;
431 }
432 };
433
434 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
435 ScrubRSClosure scrub_cl(region_bm, card_bm);
436 _g1->heap_region_iterate(&scrub_cl);
437 }
438
439 void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
440 uint worker_num, int claim_val) {
441 ScrubRSClosure scrub_cl(region_bm, card_bm);
442 _g1->heap_region_par_iterate_chunked(&scrub_cl,
443 worker_num,
444 n_workers(),
445 claim_val);
446 }
447
448 G1TriggerClosure::G1TriggerClosure() :
449 _triggered(false) { }
450
451 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
452 OopClosure* oop_cl) :
453 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
454
455 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
456 _c1(c1), _c2(c2) { }
457
458 G1UpdateRSOrPushRefOopClosure::
459 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
460 G1RemSet* rs,
461 G1ParPushHeapRSClosure* push_ref_cl,
462 bool record_refs_into_cset,
463 uint worker_i) :
464 _g1(g1h), _g1_rem_set(rs), _from(NULL),
465 _record_refs_into_cset(record_refs_into_cset),
466 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
467
468 // Returns true if the given card contains references that point
469 // into the collection set, if we're checking for such references;
470 // false otherwise.
471
472 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
473 bool check_for_refs_into_cset) {
474 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
475 err_msg("Card at "PTR_FORMAT" index "SIZE_FORMAT" representing heap at "PTR_FORMAT" (%u) must be in committed heap",
476 p2i(card_ptr),
477 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
478 _ct_bs->addr_for(card_ptr),
479 _g1->addr_to_region(_ct_bs->addr_for(card_ptr))));
480
481 // If the card is no longer dirty, nothing to do.
482 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
483 // No need to return that this card contains refs that point
484 // into the collection set.
485 return false;
486 }
487
488 // Construct the region representing the card.
489 HeapWord* start = _ct_bs->addr_for(card_ptr);
490 // And find the region containing it.
491 HeapRegion* r = _g1->heap_region_containing(start);
492
493 // Why do we have to check here whether a card is on a young region,
494 // given that we dirty young regions and, as a result, the
495 // post-barrier is supposed to filter them out and never to enqueue
496 // them? When we allocate a new region as the "allocation region" we
497 // actually dirty its cards after we release the lock, since card
498 // dirtying while holding the lock was a performance bottleneck. So,
499 // as a result, it is possible for other threads to actually
500 // allocate objects in the region (after the acquire the lock)
501 // before all the cards on the region are dirtied. This is unlikely,
502 // and it doesn't happen often, but it can happen. So, the extra
503 // check below filters out those cards.
504 if (r->is_young()) {
505 return false;
506 }
507
508 // While we are processing RSet buffers during the collection, we
509 // actually don't want to scan any cards on the collection set,
510 // since we don't want to update remebered sets with entries that
511 // point into the collection set, given that live objects from the
512 // collection set are about to move and such entries will be stale
513 // very soon. This change also deals with a reliability issue which
514 // involves scanning a card in the collection set and coming across
515 // an array that was being chunked and looking malformed. Note,
516 // however, that if evacuation fails, we have to scan any objects
517 // that were not moved and create any missing entries.
518 if (r->in_collection_set()) {
519 return false;
520 }
521
522 // The result from the hot card cache insert call is either:
523 // * pointer to the current card
524 // (implying that the current card is not 'hot'),
525 // * null
526 // (meaning we had inserted the card ptr into the "hot" card cache,
527 // which had some headroom),
528 // * a pointer to a "hot" card that was evicted from the "hot" cache.
529 //
530
531 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
532 if (hot_card_cache->use_cache()) {
533 assert(!check_for_refs_into_cset, "sanity");
534 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
535
536 card_ptr = hot_card_cache->insert(card_ptr);
537 if (card_ptr == NULL) {
538 // There was no eviction. Nothing to do.
539 return false;
540 }
541
542 start = _ct_bs->addr_for(card_ptr);
543 r = _g1->heap_region_containing(start);
544
545 // Checking whether the region we got back from the cache
546 // is young here is inappropriate. The region could have been
547 // freed, reallocated and tagged as young while in the cache.
548 // Hence we could see its young type change at any time.
549 }
550
551 // Don't use addr_for(card_ptr + 1) which can ask for
552 // a card beyond the heap. This is not safe without a perm
553 // gen at the upper end of the heap.
554 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
555 MemRegion dirtyRegion(start, end);
556
557 #if CARD_REPEAT_HISTO
558 init_ct_freq_table(_g1->max_capacity());
559 ct_freq_note_card(_ct_bs->index_for(start));
560 #endif
561
562 G1ParPushHeapRSClosure* oops_in_heap_closure = NULL;
563 if (check_for_refs_into_cset) {
564 // ConcurrentG1RefineThreads have worker numbers larger than what
565 // _cset_rs_update_cl[] is set up to handle. But those threads should
566 // only be active outside of a collection which means that when they
567 // reach here they should have check_for_refs_into_cset == false.
568 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
569 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
570 }
571 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
572 _g1->g1_rem_set(),
573 oops_in_heap_closure,
574 check_for_refs_into_cset,
575 worker_i);
576 update_rs_oop_cl.set_from(r);
577
578 G1TriggerClosure trigger_cl;
579 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
580 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
581 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
582
583 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
584 (check_for_refs_into_cset ?
585 (OopClosure*)&mux :
586 (OopClosure*)&update_rs_oop_cl));
587
588 // The region for the current card may be a young region. The
589 // current card may have been a card that was evicted from the
590 // card cache. When the card was inserted into the cache, we had
591 // determined that its region was non-young. While in the cache,
592 // the region may have been freed during a cleanup pause, reallocated
593 // and tagged as young.
594 //
595 // We wish to filter out cards for such a region but the current
596 // thread, if we're running concurrently, may "see" the young type
597 // change at any time (so an earlier "is_young" check may pass or
598 // fail arbitrarily). We tell the iteration code to perform this
599 // filtering when it has been determined that there has been an actual
600 // allocation in this region and making it safe to check the young type.
601 bool filter_young = true;
602
603 HeapWord* stop_point =
604 r->oops_on_card_seq_iterate_careful(dirtyRegion,
605 &filter_then_update_rs_oop_cl,
606 filter_young,
607 card_ptr);
608
609 // If stop_point is non-null, then we encountered an unallocated region
610 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
611 // card and re-enqueue: if we put off the card until a GC pause, then the
612 // unallocated portion will be filled in. Alternatively, we might try
613 // the full complexity of the technique used in "regular" precleaning.
614 if (stop_point != NULL) {
615 // The card might have gotten re-dirtied and re-enqueued while we
616 // worked. (In fact, it's pretty likely.)
617 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
618 *card_ptr = CardTableModRefBS::dirty_card_val();
619 MutexLockerEx x(Shared_DirtyCardQ_lock,
620 Mutex::_no_safepoint_check_flag);
621 DirtyCardQueue* sdcq =
622 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
623 sdcq->enqueue(card_ptr);
624 }
625 } else {
626 _conc_refine_cards++;
627 }
628
629 // This gets set to true if the card being refined has
630 // references that point into the collection set.
631 bool has_refs_into_cset = trigger_cl.triggered();
632
633 // We should only be detecting that the card contains references
634 // that point into the collection set if the current thread is
635 // a GC worker thread.
636 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
637 "invalid result at non safepoint");
638
639 return has_refs_into_cset;
640 }
641
642 void G1RemSet::print_periodic_summary_info(const char* header) {
643 G1RemSetSummary current;
644 current.initialize(this);
645
646 _prev_period_summary.subtract_from(¤t);
647 print_summary_info(&_prev_period_summary, header);
648
649 _prev_period_summary.set(¤t);
650 }
651
652 void G1RemSet::print_summary_info() {
653 G1RemSetSummary current;
654 current.initialize(this);
655
656 print_summary_info(¤t, " Cumulative RS summary");
657 }
658
659 void G1RemSet::print_summary_info(G1RemSetSummary * summary, const char * header) {
660 assert(summary != NULL, "just checking");
661
662 if (header != NULL) {
663 gclog_or_tty->print_cr("%s", header);
664 }
665
666 #if CARD_REPEAT_HISTO
667 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
668 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
669 card_repeat_count.print_on(gclog_or_tty);
670 #endif
671
672 summary->print_on(gclog_or_tty);
673 }
674
675 void G1RemSet::prepare_for_verify() {
676 if (G1HRRSFlushLogBuffersOnVerify &&
677 (VerifyBeforeGC || VerifyAfterGC)
678 && (!_g1->full_collection() || G1VerifyRSetsDuringFullGC)) {
679 cleanupHRRS();
680 _g1->set_refine_cte_cl_concurrency(false);
681 if (SafepointSynchronize::is_at_safepoint()) {
682 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
683 dcqs.concatenate_logs();
684 }
685
686 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
687 bool use_hot_card_cache = hot_card_cache->use_cache();
688 hot_card_cache->set_use_cache(false);
689
690 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
691 updateRS(&into_cset_dcq, 0);
692 _g1->into_cset_dirty_card_queue_set().clear();
693
694 hot_card_cache->set_use_cache(use_hot_card_cache);
695 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
696 }
697 }