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(OopsInHeapRegionClosure*, 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(OopsInHeapRegionClosure*, _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 OopsInHeapRegionClosure* _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(OopsInHeapRegionClosure* 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 HeapRegionDCTOC::IntoCSFilterKind);
147
148 // Set the "from" region in the closure.
149 _oc->set_region(r);
150 MemRegion card_region(_bot_shared->address_for_index(index), G1BlockOffsetSharedArray::N_words);
151 MemRegion pre_gc_allocated(r->bottom(), r->scan_top());
152 MemRegion mr = pre_gc_allocated.intersection(card_region);
153 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
154 // We make the card as "claimed" lazily (so races are possible
155 // but they're benign), which reduces the number of duplicate
156 // scans (the rsets of the regions in the cset can intersect).
157 _ct_bs->set_card_claimed(index);
158 _cards_done++;
159 cl.do_MemRegion(mr);
160 }
161 }
162
163 void printCard(HeapRegion* card_region, size_t card_index,
164 HeapWord* card_start) {
165 gclog_or_tty->print_cr("T " UINT32_FORMAT " Region [" PTR_FORMAT ", " PTR_FORMAT ") "
166 "RS names card %p: "
167 "[" PTR_FORMAT ", " PTR_FORMAT ")",
168 _worker_i,
169 card_region->bottom(), card_region->end(),
170 card_index,
171 card_start, card_start + G1BlockOffsetSharedArray::N_words);
172 }
173
174 void scan_strong_code_roots(HeapRegion* r) {
175 double scan_start = os::elapsedTime();
176 r->strong_code_roots_do(_code_root_cl);
177 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
178 }
179
180 bool doHeapRegion(HeapRegion* r) {
181 assert(r->in_collection_set(), "should only be called on elements of CS.");
182 HeapRegionRemSet* hrrs = r->rem_set();
183 if (hrrs->iter_is_complete()) return false; // All done.
184 if (!_try_claimed && !hrrs->claim_iter()) return false;
185 // If we ever free the collection set concurrently, we should also
186 // clear the card table concurrently therefore we won't need to
187 // add regions of the collection set to the dirty cards region.
188 _g1h->push_dirty_cards_region(r);
189 // If we didn't return above, then
190 // _try_claimed || r->claim_iter()
191 // is true: either we're supposed to work on claimed-but-not-complete
192 // regions, or we successfully claimed the region.
193
194 HeapRegionRemSetIterator iter(hrrs);
195 size_t card_index;
196
197 // We claim cards in block so as to recude the contention. The block size is determined by
198 // the G1RSetScanBlockSize parameter.
199 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
200 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
201 if (current_card >= jump_to_card + _block_size) {
202 jump_to_card = hrrs->iter_claimed_next(_block_size);
203 }
204 if (current_card < jump_to_card) continue;
205 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
206 #if 0
207 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
208 card_start, card_start + CardTableModRefBS::card_size_in_words);
209 #endif
210
211 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
212 _cards++;
213
214 if (!card_region->is_on_dirty_cards_region_list()) {
215 _g1h->push_dirty_cards_region(card_region);
216 }
217
218 // If the card is dirty, then we will scan it during updateRS.
219 if (!card_region->in_collection_set() &&
220 !_ct_bs->is_card_dirty(card_index)) {
221 scanCard(card_index, card_region);
222 }
223 }
224 if (!_try_claimed) {
225 // Scan the strong code root list attached to the current region
226 scan_strong_code_roots(r);
227
228 hrrs->set_iter_complete();
229 }
230 return false;
231 }
232
233 double strong_code_root_scan_time_sec() {
234 return _strong_code_root_scan_time_sec;
235 }
236
237 size_t cards_done() { return _cards_done;}
238 size_t cards_looked_up() { return _cards;}
239 };
240
241 void G1RemSet::scanRS(OopsInHeapRegionClosure* oc,
242 CodeBlobClosure* code_root_cl,
243 uint worker_i) {
244 double rs_time_start = os::elapsedTime();
245 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
246
247 ScanRSClosure scanRScl(oc, code_root_cl, worker_i);
248
249 _g1->collection_set_iterate_from(startRegion, &scanRScl);
250 scanRScl.set_try_claimed();
251 _g1->collection_set_iterate_from(startRegion, &scanRScl);
252
253 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
254 - scanRScl.strong_code_root_scan_time_sec();
255
256 assert(_cards_scanned != NULL, "invariant");
257 _cards_scanned[worker_i] = scanRScl.cards_done();
258
259 _g1p->phase_times()->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
260 _g1p->phase_times()->record_strong_code_root_scan_time(worker_i,
261 scanRScl.strong_code_root_scan_time_sec() * 1000.0);
262 }
263
264 // Closure used for updating RSets and recording references that
265 // point into the collection set. Only called during an
266 // evacuation pause.
267
268 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
269 G1RemSet* _g1rs;
270 DirtyCardQueue* _into_cset_dcq;
271 public:
272 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
273 DirtyCardQueue* into_cset_dcq) :
274 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
275 {}
276 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
277 // The only time we care about recording cards that
278 // contain references that point into the collection set
279 // is during RSet updating within an evacuation pause.
280 // In this case worker_i should be the id of a GC worker thread.
281 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
282 assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), "should be a GC worker");
283
284 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
285 // 'card_ptr' contains references that point into the collection
286 // set. We need to record the card in the DCQS
287 // (G1CollectedHeap::into_cset_dirty_card_queue_set())
288 // that's used for that purpose.
289 //
290 // Enqueue the card
291 _into_cset_dcq->enqueue(card_ptr);
292 }
293 return true;
294 }
295 };
296
297 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
298 double start = os::elapsedTime();
299 // Apply the given closure to all remaining log entries.
300 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
301
302 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i);
303
304 // Now there should be no dirty cards.
305 if (G1RSLogCheckCardTable) {
306 CountNonCleanMemRegionClosure cl(_g1);
307 _ct_bs->mod_card_iterate(&cl);
308 // XXX This isn't true any more: keeping cards of young regions
309 // marked dirty broke it. Need some reasonable fix.
310 guarantee(cl.n() == 0, "Card table should be clean.");
311 }
312
313 _g1p->phase_times()->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
314 }
315
316 void G1RemSet::cleanupHRRS() {
317 HeapRegionRemSet::cleanup();
318 }
319
320 void G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
321 CodeBlobClosure* code_root_cl,
322 uint worker_i) {
323 #if CARD_REPEAT_HISTO
324 ct_freq_update_histo_and_reset();
325 #endif
326
327 // We cache the value of 'oc' closure into the appropriate slot in the
328 // _cset_rs_update_cl for this worker
329 assert(worker_i < n_workers(), "sanity");
330 _cset_rs_update_cl[worker_i] = oc;
331
332 // A DirtyCardQueue that is used to hold cards containing references
333 // that point into the collection set. This DCQ is associated with a
334 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
335 // circumstances (i.e. the pause successfully completes), these cards
336 // are just discarded (there's no need to update the RSets of regions
337 // that were in the collection set - after the pause these regions
338 // are wholly 'free' of live objects. In the event of an evacuation
339 // failure the cards/buffers in this queue set are passed to the
340 // DirtyCardQueueSet that is used to manage RSet updates
341 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
342
343 assert((ParallelGCThreads > 0) || worker_i == 0, "invariant");
344
345 // The two flags below were introduced temporarily to serialize
346 // the updating and scanning of remembered sets. There are some
347 // race conditions when these two operations are done in parallel
348 // and they are causing failures. When we resolve said race
349 // conditions, we'll revert back to parallel remembered set
350 // updating and scanning. See CRs 6677707 and 6677708.
351 if (G1UseParallelRSetUpdating || (worker_i == 0)) {
352 updateRS(&into_cset_dcq, worker_i);
353 } else {
354 _g1p->phase_times()->record_update_rs_processed_buffers(worker_i, 0);
355 _g1p->phase_times()->record_update_rs_time(worker_i, 0.0);
356 }
357 if (G1UseParallelRSetScanning || (worker_i == 0)) {
358 scanRS(oc, code_root_cl, worker_i);
359 } else {
360 _g1p->phase_times()->record_scan_rs_time(worker_i, 0.0);
361 }
362
363 // We now clear the cached values of _cset_rs_update_cl for this worker
364 _cset_rs_update_cl[worker_i] = NULL;
365 }
366
367 void G1RemSet::prepare_for_oops_into_collection_set_do() {
368 cleanupHRRS();
369 _g1->set_refine_cte_cl_concurrency(false);
370 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
371 dcqs.concatenate_logs();
372
373 guarantee( _cards_scanned == NULL, "invariant" );
374 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers(), mtGC);
375 for (uint i = 0; i < n_workers(); ++i) {
376 _cards_scanned[i] = 0;
377 }
378 _total_cards_scanned = 0;
379 }
380
381 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
382 guarantee( _cards_scanned != NULL, "invariant" );
383 _total_cards_scanned = 0;
384 for (uint i = 0; i < n_workers(); ++i) {
385 _total_cards_scanned += _cards_scanned[i];
386 }
387 FREE_C_HEAP_ARRAY(size_t, _cards_scanned, mtGC);
388 _cards_scanned = NULL;
389 // Cleanup after copy
390 _g1->set_refine_cte_cl_concurrency(true);
391 // Set all cards back to clean.
392 _g1->cleanUpCardTable();
393
394 DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
395 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
396
397 if (_g1->evacuation_failed()) {
398 double restore_remembered_set_start = os::elapsedTime();
399
400 // Restore remembered sets for the regions pointing into the collection set.
401 // We just need to transfer the completed buffers from the DirtyCardQueueSet
402 // used to hold cards that contain references that point into the collection set
403 // to the DCQS used to hold the deferred RS updates.
404 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
405 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
406 }
407
408 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
409 // which contain references that point into the collection.
410 _g1->into_cset_dirty_card_queue_set().clear();
411 assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
412 "all buffers should be freed");
413 _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
414 }
415
416 class ScrubRSClosure: public HeapRegionClosure {
417 G1CollectedHeap* _g1h;
418 BitMap* _region_bm;
419 BitMap* _card_bm;
420 CardTableModRefBS* _ctbs;
421 public:
422 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
423 _g1h(G1CollectedHeap::heap()),
424 _region_bm(region_bm), _card_bm(card_bm),
425 _ctbs(_g1h->g1_barrier_set()) {}
426
427 bool doHeapRegion(HeapRegion* r) {
428 if (!r->continuesHumongous()) {
429 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
430 }
431 return false;
432 }
433 };
434
435 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
436 ScrubRSClosure scrub_cl(region_bm, card_bm);
437 _g1->heap_region_iterate(&scrub_cl);
438 }
439
440 void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
441 uint worker_num, int claim_val) {
442 ScrubRSClosure scrub_cl(region_bm, card_bm);
443 _g1->heap_region_par_iterate_chunked(&scrub_cl,
444 worker_num,
445 n_workers(),
446 claim_val);
447 }
448
449 G1TriggerClosure::G1TriggerClosure() :
450 _triggered(false) { }
451
452 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
453 OopClosure* oop_cl) :
454 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
455
456 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
457 _c1(c1), _c2(c2) { }
458
459 G1UpdateRSOrPushRefOopClosure::
460 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
461 G1RemSet* rs,
462 OopsInHeapRegionClosure* push_ref_cl,
463 bool record_refs_into_cset,
464 uint worker_i) :
465 _g1(g1h), _g1_rem_set(rs), _from(NULL),
466 _record_refs_into_cset(record_refs_into_cset),
467 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
468
469 // Returns true if the given card contains references that point
470 // into the collection set, if we're checking for such references;
471 // false otherwise.
472
473 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
474 bool check_for_refs_into_cset) {
475 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
476 err_msg("Card at "PTR_FORMAT" index "SIZE_FORMAT" representing heap at "PTR_FORMAT" (%u) must be in committed heap",
477 p2i(card_ptr),
478 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
479 _ct_bs->addr_for(card_ptr),
480 _g1->addr_to_region(_ct_bs->addr_for(card_ptr))));
481
482 // If the card is no longer dirty, nothing to do.
483 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
484 // No need to return that this card contains refs that point
485 // into the collection set.
486 return false;
487 }
488
489 // Construct the region representing the card.
490 HeapWord* start = _ct_bs->addr_for(card_ptr);
491 // And find the region containing it.
492 HeapRegion* r = _g1->heap_region_containing(start);
493
494 // Why do we have to check here whether a card is on a young region,
495 // given that we dirty young regions and, as a result, the
496 // post-barrier is supposed to filter them out and never to enqueue
497 // them? When we allocate a new region as the "allocation region" we
498 // actually dirty its cards after we release the lock, since card
499 // dirtying while holding the lock was a performance bottleneck. So,
500 // as a result, it is possible for other threads to actually
501 // allocate objects in the region (after the acquire the lock)
502 // before all the cards on the region are dirtied. This is unlikely,
503 // and it doesn't happen often, but it can happen. So, the extra
504 // check below filters out those cards.
505 if (r->is_young()) {
506 return false;
507 }
508
509 // While we are processing RSet buffers during the collection, we
510 // actually don't want to scan any cards on the collection set,
511 // since we don't want to update remebered sets with entries that
512 // point into the collection set, given that live objects from the
513 // collection set are about to move and such entries will be stale
514 // very soon. This change also deals with a reliability issue which
515 // involves scanning a card in the collection set and coming across
516 // an array that was being chunked and looking malformed. Note,
517 // however, that if evacuation fails, we have to scan any objects
518 // that were not moved and create any missing entries.
519 if (r->in_collection_set()) {
520 return false;
521 }
522
523 // The result from the hot card cache insert call is either:
524 // * pointer to the current card
525 // (implying that the current card is not 'hot'),
526 // * null
527 // (meaning we had inserted the card ptr into the "hot" card cache,
528 // which had some headroom),
529 // * a pointer to a "hot" card that was evicted from the "hot" cache.
530 //
531
532 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
533 if (hot_card_cache->use_cache()) {
534 assert(!check_for_refs_into_cset, "sanity");
535 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
536
537 card_ptr = hot_card_cache->insert(card_ptr);
538 if (card_ptr == NULL) {
539 // There was no eviction. Nothing to do.
540 return false;
541 }
542
543 start = _ct_bs->addr_for(card_ptr);
544 r = _g1->heap_region_containing(start);
545
546 // Checking whether the region we got back from the cache
547 // is young here is inappropriate. The region could have been
548 // freed, reallocated and tagged as young while in the cache.
549 // Hence we could see its young type change at any time.
550 }
551
552 // Don't use addr_for(card_ptr + 1) which can ask for
553 // a card beyond the heap. This is not safe without a perm
554 // gen at the upper end of the heap.
555 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
556 MemRegion dirtyRegion(start, end);
557
558 #if CARD_REPEAT_HISTO
559 init_ct_freq_table(_g1->max_capacity());
560 ct_freq_note_card(_ct_bs->index_for(start));
561 #endif
562
563 OopsInHeapRegionClosure* oops_in_heap_closure = NULL;
564 if (check_for_refs_into_cset) {
565 // ConcurrentG1RefineThreads have worker numbers larger than what
566 // _cset_rs_update_cl[] is set up to handle. But those threads should
567 // only be active outside of a collection which means that when they
568 // reach here they should have check_for_refs_into_cset == false.
569 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
570 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
571 }
572 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
573 _g1->g1_rem_set(),
574 oops_in_heap_closure,
575 check_for_refs_into_cset,
576 worker_i);
577 update_rs_oop_cl.set_from(r);
578
579 G1TriggerClosure trigger_cl;
580 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
581 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
582 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
583
584 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
585 (check_for_refs_into_cset ?
586 (OopClosure*)&mux :
587 (OopClosure*)&update_rs_oop_cl));
588
589 // The region for the current card may be a young region. The
590 // current card may have been a card that was evicted from the
591 // card cache. When the card was inserted into the cache, we had
592 // determined that its region was non-young. While in the cache,
593 // the region may have been freed during a cleanup pause, reallocated
594 // and tagged as young.
595 //
596 // We wish to filter out cards for such a region but the current
597 // thread, if we're running concurrently, may "see" the young type
598 // change at any time (so an earlier "is_young" check may pass or
599 // fail arbitrarily). We tell the iteration code to perform this
600 // filtering when it has been determined that there has been an actual
601 // allocation in this region and making it safe to check the young type.
602 bool filter_young = true;
603
604 HeapWord* stop_point =
605 r->oops_on_card_seq_iterate_careful(dirtyRegion,
606 &filter_then_update_rs_oop_cl,
607 filter_young,
608 card_ptr);
609
610 // If stop_point is non-null, then we encountered an unallocated region
611 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
612 // card and re-enqueue: if we put off the card until a GC pause, then the
613 // unallocated portion will be filled in. Alternatively, we might try
614 // the full complexity of the technique used in "regular" precleaning.
615 if (stop_point != NULL) {
616 // The card might have gotten re-dirtied and re-enqueued while we
617 // worked. (In fact, it's pretty likely.)
618 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
619 *card_ptr = CardTableModRefBS::dirty_card_val();
620 MutexLockerEx x(Shared_DirtyCardQ_lock,
621 Mutex::_no_safepoint_check_flag);
622 DirtyCardQueue* sdcq =
623 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
624 sdcq->enqueue(card_ptr);
625 }
626 } else {
627 _conc_refine_cards++;
628 }
629
630 // This gets set to true if the card being refined has
631 // references that point into the collection set.
632 bool has_refs_into_cset = trigger_cl.triggered();
633
634 // We should only be detecting that the card contains references
635 // that point into the collection set if the current thread is
636 // a GC worker thread.
637 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
638 "invalid result at non safepoint");
639
640 return has_refs_into_cset;
641 }
642
643 void G1RemSet::print_periodic_summary_info(const char* header) {
644 G1RemSetSummary current;
645 current.initialize(this);
646
647 _prev_period_summary.subtract_from(¤t);
648 print_summary_info(&_prev_period_summary, header);
649
650 _prev_period_summary.set(¤t);
651 }
652
653 void G1RemSet::print_summary_info() {
654 G1RemSetSummary current;
655 current.initialize(this);
656
657 print_summary_info(¤t, " Cumulative RS summary");
658 }
659
660 void G1RemSet::print_summary_info(G1RemSetSummary * summary, const char * header) {
661 assert(summary != NULL, "just checking");
662
663 if (header != NULL) {
664 gclog_or_tty->print_cr("%s", header);
665 }
666
667 #if CARD_REPEAT_HISTO
668 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
669 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
670 card_repeat_count.print_on(gclog_or_tty);
671 #endif
672
673 summary->print_on(gclog_or_tty);
674 }
675
676 void G1RemSet::prepare_for_verify() {
677 if (G1HRRSFlushLogBuffersOnVerify &&
678 (VerifyBeforeGC || VerifyAfterGC)
679 && (!_g1->full_collection() || G1VerifyRSetsDuringFullGC)) {
680 cleanupHRRS();
681 _g1->set_refine_cte_cl_concurrency(false);
682 if (SafepointSynchronize::is_at_safepoint()) {
683 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
684 dcqs.concatenate_logs();
685 }
686
687 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
688 bool use_hot_card_cache = hot_card_cache->use_cache();
689 hot_card_cache->set_use_cache(false);
690
691 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
692 updateRS(&into_cset_dcq, 0);
693 _g1->into_cset_dirty_card_queue_set().clear();
694
695 hot_card_cache->set_use_cache(use_hot_card_cache);
696 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
697 }
698 }