Thu, 23 Oct 2014 12:02:08 -0700
Merge
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 */
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"
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43 #define CARD_REPEAT_HISTO 0
45 #if CARD_REPEAT_HISTO
46 static size_t ct_freq_sz;
47 static jbyte* ct_freq = NULL;
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 }
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 }
62 static IntHistogram card_repeat_count(10, 10);
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 }
70 }
71 #endif
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 }
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 }
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 }
107 class ScanRSClosure : public HeapRegionClosure {
108 size_t _cards_done, _cards;
109 G1CollectedHeap* _g1h;
111 OopsInHeapRegionClosure* _oc;
112 CodeBlobClosure* _code_root_cl;
114 G1BlockOffsetSharedArray* _bot_shared;
115 G1SATBCardTableModRefBS *_ct_bs;
117 double _strong_code_root_scan_time_sec;
118 uint _worker_i;
119 int _block_size;
120 bool _try_claimed;
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 }
140 void set_try_claimed() { _try_claimed = true; }
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);
148 // Set the "from" region in the closure.
149 _oc->set_region(r);
150 HeapWord* card_start = _bot_shared->address_for_index(index);
151 HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words;
152 Space *sp = SharedHeap::heap()->space_containing(card_start);
153 MemRegion sm_region = sp->used_region_at_save_marks();
154 MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end));
155 if (!mr.is_empty() && !_ct_bs->is_card_claimed(index)) {
156 // We make the card as "claimed" lazily (so races are possible
157 // but they're benign), which reduces the number of duplicate
158 // scans (the rsets of the regions in the cset can intersect).
159 _ct_bs->set_card_claimed(index);
160 _cards_done++;
161 cl.do_MemRegion(mr);
162 }
163 }
165 void printCard(HeapRegion* card_region, size_t card_index,
166 HeapWord* card_start) {
167 gclog_or_tty->print_cr("T " UINT32_FORMAT " Region [" PTR_FORMAT ", " PTR_FORMAT ") "
168 "RS names card %p: "
169 "[" PTR_FORMAT ", " PTR_FORMAT ")",
170 _worker_i,
171 card_region->bottom(), card_region->end(),
172 card_index,
173 card_start, card_start + G1BlockOffsetSharedArray::N_words);
174 }
176 void scan_strong_code_roots(HeapRegion* r) {
177 double scan_start = os::elapsedTime();
178 r->strong_code_roots_do(_code_root_cl);
179 _strong_code_root_scan_time_sec += (os::elapsedTime() - scan_start);
180 }
182 bool doHeapRegion(HeapRegion* r) {
183 assert(r->in_collection_set(), "should only be called on elements of CS.");
184 HeapRegionRemSet* hrrs = r->rem_set();
185 if (hrrs->iter_is_complete()) return false; // All done.
186 if (!_try_claimed && !hrrs->claim_iter()) return false;
187 // If we ever free the collection set concurrently, we should also
188 // clear the card table concurrently therefore we won't need to
189 // add regions of the collection set to the dirty cards region.
190 _g1h->push_dirty_cards_region(r);
191 // If we didn't return above, then
192 // _try_claimed || r->claim_iter()
193 // is true: either we're supposed to work on claimed-but-not-complete
194 // regions, or we successfully claimed the region.
196 HeapRegionRemSetIterator iter(hrrs);
197 size_t card_index;
199 // We claim cards in block so as to recude the contention. The block size is determined by
200 // the G1RSetScanBlockSize parameter.
201 size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
202 for (size_t current_card = 0; iter.has_next(card_index); current_card++) {
203 if (current_card >= jump_to_card + _block_size) {
204 jump_to_card = hrrs->iter_claimed_next(_block_size);
205 }
206 if (current_card < jump_to_card) continue;
207 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
208 #if 0
209 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
210 card_start, card_start + CardTableModRefBS::card_size_in_words);
211 #endif
213 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
214 _cards++;
216 if (!card_region->is_on_dirty_cards_region_list()) {
217 _g1h->push_dirty_cards_region(card_region);
218 }
220 // If the card is dirty, then we will scan it during updateRS.
221 if (!card_region->in_collection_set() &&
222 !_ct_bs->is_card_dirty(card_index)) {
223 scanCard(card_index, card_region);
224 }
225 }
226 if (!_try_claimed) {
227 // Scan the strong code root list attached to the current region
228 scan_strong_code_roots(r);
230 hrrs->set_iter_complete();
231 }
232 return false;
233 }
235 double strong_code_root_scan_time_sec() {
236 return _strong_code_root_scan_time_sec;
237 }
239 size_t cards_done() { return _cards_done;}
240 size_t cards_looked_up() { return _cards;}
241 };
243 void G1RemSet::scanRS(OopsInHeapRegionClosure* oc,
244 CodeBlobClosure* code_root_cl,
245 uint worker_i) {
246 double rs_time_start = os::elapsedTime();
247 HeapRegion *startRegion = _g1->start_cset_region_for_worker(worker_i);
249 ScanRSClosure scanRScl(oc, code_root_cl, worker_i);
251 _g1->collection_set_iterate_from(startRegion, &scanRScl);
252 scanRScl.set_try_claimed();
253 _g1->collection_set_iterate_from(startRegion, &scanRScl);
255 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start)
256 - scanRScl.strong_code_root_scan_time_sec();
258 assert(_cards_scanned != NULL, "invariant");
259 _cards_scanned[worker_i] = scanRScl.cards_done();
261 _g1p->phase_times()->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
262 _g1p->phase_times()->record_strong_code_root_scan_time(worker_i,
263 scanRScl.strong_code_root_scan_time_sec() * 1000.0);
264 }
266 // Closure used for updating RSets and recording references that
267 // point into the collection set. Only called during an
268 // evacuation pause.
270 class RefineRecordRefsIntoCSCardTableEntryClosure: public CardTableEntryClosure {
271 G1RemSet* _g1rs;
272 DirtyCardQueue* _into_cset_dcq;
273 public:
274 RefineRecordRefsIntoCSCardTableEntryClosure(G1CollectedHeap* g1h,
275 DirtyCardQueue* into_cset_dcq) :
276 _g1rs(g1h->g1_rem_set()), _into_cset_dcq(into_cset_dcq)
277 {}
278 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
279 // The only time we care about recording cards that
280 // contain references that point into the collection set
281 // is during RSet updating within an evacuation pause.
282 // In this case worker_i should be the id of a GC worker thread.
283 assert(SafepointSynchronize::is_at_safepoint(), "not during an evacuation pause");
284 assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), "should be a GC worker");
286 if (_g1rs->refine_card(card_ptr, worker_i, true)) {
287 // 'card_ptr' contains references that point into the collection
288 // set. We need to record the card in the DCQS
289 // (G1CollectedHeap::into_cset_dirty_card_queue_set())
290 // that's used for that purpose.
291 //
292 // Enqueue the card
293 _into_cset_dcq->enqueue(card_ptr);
294 }
295 return true;
296 }
297 };
299 void G1RemSet::updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i) {
300 double start = os::elapsedTime();
301 // Apply the given closure to all remaining log entries.
302 RefineRecordRefsIntoCSCardTableEntryClosure into_cset_update_rs_cl(_g1, into_cset_dcq);
304 _g1->iterate_dirty_card_closure(&into_cset_update_rs_cl, into_cset_dcq, false, worker_i);
306 // Now there should be no dirty cards.
307 if (G1RSLogCheckCardTable) {
308 CountNonCleanMemRegionClosure cl(_g1);
309 _ct_bs->mod_card_iterate(&cl);
310 // XXX This isn't true any more: keeping cards of young regions
311 // marked dirty broke it. Need some reasonable fix.
312 guarantee(cl.n() == 0, "Card table should be clean.");
313 }
315 _g1p->phase_times()->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
316 }
318 void G1RemSet::cleanupHRRS() {
319 HeapRegionRemSet::cleanup();
320 }
322 void G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
323 CodeBlobClosure* code_root_cl,
324 uint worker_i) {
325 #if CARD_REPEAT_HISTO
326 ct_freq_update_histo_and_reset();
327 #endif
329 // We cache the value of 'oc' closure into the appropriate slot in the
330 // _cset_rs_update_cl for this worker
331 assert(worker_i < n_workers(), "sanity");
332 _cset_rs_update_cl[worker_i] = oc;
334 // A DirtyCardQueue that is used to hold cards containing references
335 // that point into the collection set. This DCQ is associated with a
336 // special DirtyCardQueueSet (see g1CollectedHeap.hpp). Under normal
337 // circumstances (i.e. the pause successfully completes), these cards
338 // are just discarded (there's no need to update the RSets of regions
339 // that were in the collection set - after the pause these regions
340 // are wholly 'free' of live objects. In the event of an evacuation
341 // failure the cards/buffers in this queue set are passed to the
342 // DirtyCardQueueSet that is used to manage RSet updates
343 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
345 assert((ParallelGCThreads > 0) || worker_i == 0, "invariant");
347 // The two flags below were introduced temporarily to serialize
348 // the updating and scanning of remembered sets. There are some
349 // race conditions when these two operations are done in parallel
350 // and they are causing failures. When we resolve said race
351 // conditions, we'll revert back to parallel remembered set
352 // updating and scanning. See CRs 6677707 and 6677708.
353 if (G1UseParallelRSetUpdating || (worker_i == 0)) {
354 updateRS(&into_cset_dcq, worker_i);
355 } else {
356 _g1p->phase_times()->record_update_rs_processed_buffers(worker_i, 0);
357 _g1p->phase_times()->record_update_rs_time(worker_i, 0.0);
358 }
359 if (G1UseParallelRSetScanning || (worker_i == 0)) {
360 scanRS(oc, code_root_cl, worker_i);
361 } else {
362 _g1p->phase_times()->record_scan_rs_time(worker_i, 0.0);
363 }
365 // We now clear the cached values of _cset_rs_update_cl for this worker
366 _cset_rs_update_cl[worker_i] = NULL;
367 }
369 void G1RemSet::prepare_for_oops_into_collection_set_do() {
370 cleanupHRRS();
371 _g1->set_refine_cte_cl_concurrency(false);
372 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
373 dcqs.concatenate_logs();
375 guarantee( _cards_scanned == NULL, "invariant" );
376 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers(), mtGC);
377 for (uint i = 0; i < n_workers(); ++i) {
378 _cards_scanned[i] = 0;
379 }
380 _total_cards_scanned = 0;
381 }
383 void G1RemSet::cleanup_after_oops_into_collection_set_do() {
384 guarantee( _cards_scanned != NULL, "invariant" );
385 _total_cards_scanned = 0;
386 for (uint i = 0; i < n_workers(); ++i) {
387 _total_cards_scanned += _cards_scanned[i];
388 }
389 FREE_C_HEAP_ARRAY(size_t, _cards_scanned, mtGC);
390 _cards_scanned = NULL;
391 // Cleanup after copy
392 _g1->set_refine_cte_cl_concurrency(true);
393 // Set all cards back to clean.
394 _g1->cleanUpCardTable();
396 DirtyCardQueueSet& into_cset_dcqs = _g1->into_cset_dirty_card_queue_set();
397 int into_cset_n_buffers = into_cset_dcqs.completed_buffers_num();
399 if (_g1->evacuation_failed()) {
400 double restore_remembered_set_start = os::elapsedTime();
402 // Restore remembered sets for the regions pointing into the collection set.
403 // We just need to transfer the completed buffers from the DirtyCardQueueSet
404 // used to hold cards that contain references that point into the collection set
405 // to the DCQS used to hold the deferred RS updates.
406 _g1->dirty_card_queue_set().merge_bufferlists(&into_cset_dcqs);
407 _g1->g1_policy()->phase_times()->record_evac_fail_restore_remsets((os::elapsedTime() - restore_remembered_set_start) * 1000.0);
408 }
410 // Free any completed buffers in the DirtyCardQueueSet used to hold cards
411 // which contain references that point into the collection.
412 _g1->into_cset_dirty_card_queue_set().clear();
413 assert(_g1->into_cset_dirty_card_queue_set().completed_buffers_num() == 0,
414 "all buffers should be freed");
415 _g1->into_cset_dirty_card_queue_set().clear_n_completed_buffers();
416 }
418 class ScrubRSClosure: public HeapRegionClosure {
419 G1CollectedHeap* _g1h;
420 BitMap* _region_bm;
421 BitMap* _card_bm;
422 CardTableModRefBS* _ctbs;
423 public:
424 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
425 _g1h(G1CollectedHeap::heap()),
426 _region_bm(region_bm), _card_bm(card_bm),
427 _ctbs(_g1h->g1_barrier_set()) {}
429 bool doHeapRegion(HeapRegion* r) {
430 if (!r->continuesHumongous()) {
431 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
432 }
433 return false;
434 }
435 };
437 void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
438 ScrubRSClosure scrub_cl(region_bm, card_bm);
439 _g1->heap_region_iterate(&scrub_cl);
440 }
442 void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
443 uint worker_num, int claim_val) {
444 ScrubRSClosure scrub_cl(region_bm, card_bm);
445 _g1->heap_region_par_iterate_chunked(&scrub_cl,
446 worker_num,
447 n_workers(),
448 claim_val);
449 }
451 G1TriggerClosure::G1TriggerClosure() :
452 _triggered(false) { }
454 G1InvokeIfNotTriggeredClosure::G1InvokeIfNotTriggeredClosure(G1TriggerClosure* t_cl,
455 OopClosure* oop_cl) :
456 _trigger_cl(t_cl), _oop_cl(oop_cl) { }
458 G1Mux2Closure::G1Mux2Closure(OopClosure *c1, OopClosure *c2) :
459 _c1(c1), _c2(c2) { }
461 G1UpdateRSOrPushRefOopClosure::
462 G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
463 G1RemSet* rs,
464 OopsInHeapRegionClosure* push_ref_cl,
465 bool record_refs_into_cset,
466 uint worker_i) :
467 _g1(g1h), _g1_rem_set(rs), _from(NULL),
468 _record_refs_into_cset(record_refs_into_cset),
469 _push_ref_cl(push_ref_cl), _worker_i(worker_i) { }
471 // Returns true if the given card contains references that point
472 // into the collection set, if we're checking for such references;
473 // false otherwise.
475 bool G1RemSet::refine_card(jbyte* card_ptr, uint worker_i,
476 bool check_for_refs_into_cset) {
477 assert(_g1->is_in_exact(_ct_bs->addr_for(card_ptr)),
478 err_msg("Card at "PTR_FORMAT" index "SIZE_FORMAT" representing heap at "PTR_FORMAT" (%u) must be in committed heap",
479 p2i(card_ptr),
480 _ct_bs->index_for(_ct_bs->addr_for(card_ptr)),
481 _ct_bs->addr_for(card_ptr),
482 _g1->addr_to_region(_ct_bs->addr_for(card_ptr))));
484 // If the card is no longer dirty, nothing to do.
485 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
486 // No need to return that this card contains refs that point
487 // into the collection set.
488 return false;
489 }
491 // Construct the region representing the card.
492 HeapWord* start = _ct_bs->addr_for(card_ptr);
493 // And find the region containing it.
494 HeapRegion* r = _g1->heap_region_containing(start);
496 // Why do we have to check here whether a card is on a young region,
497 // given that we dirty young regions and, as a result, the
498 // post-barrier is supposed to filter them out and never to enqueue
499 // them? When we allocate a new region as the "allocation region" we
500 // actually dirty its cards after we release the lock, since card
501 // dirtying while holding the lock was a performance bottleneck. So,
502 // as a result, it is possible for other threads to actually
503 // allocate objects in the region (after the acquire the lock)
504 // before all the cards on the region are dirtied. This is unlikely,
505 // and it doesn't happen often, but it can happen. So, the extra
506 // check below filters out those cards.
507 if (r->is_young()) {
508 return false;
509 }
511 // While we are processing RSet buffers during the collection, we
512 // actually don't want to scan any cards on the collection set,
513 // since we don't want to update remebered sets with entries that
514 // point into the collection set, given that live objects from the
515 // collection set are about to move and such entries will be stale
516 // very soon. This change also deals with a reliability issue which
517 // involves scanning a card in the collection set and coming across
518 // an array that was being chunked and looking malformed. Note,
519 // however, that if evacuation fails, we have to scan any objects
520 // that were not moved and create any missing entries.
521 if (r->in_collection_set()) {
522 return false;
523 }
525 // The result from the hot card cache insert call is either:
526 // * pointer to the current card
527 // (implying that the current card is not 'hot'),
528 // * null
529 // (meaning we had inserted the card ptr into the "hot" card cache,
530 // which had some headroom),
531 // * a pointer to a "hot" card that was evicted from the "hot" cache.
532 //
534 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
535 if (hot_card_cache->use_cache()) {
536 assert(!check_for_refs_into_cset, "sanity");
537 assert(!SafepointSynchronize::is_at_safepoint(), "sanity");
539 card_ptr = hot_card_cache->insert(card_ptr);
540 if (card_ptr == NULL) {
541 // There was no eviction. Nothing to do.
542 return false;
543 }
545 start = _ct_bs->addr_for(card_ptr);
546 r = _g1->heap_region_containing(start);
548 // Checking whether the region we got back from the cache
549 // is young here is inappropriate. The region could have been
550 // freed, reallocated and tagged as young while in the cache.
551 // Hence we could see its young type change at any time.
552 }
554 // Don't use addr_for(card_ptr + 1) which can ask for
555 // a card beyond the heap. This is not safe without a perm
556 // gen at the upper end of the heap.
557 HeapWord* end = start + CardTableModRefBS::card_size_in_words;
558 MemRegion dirtyRegion(start, end);
560 #if CARD_REPEAT_HISTO
561 init_ct_freq_table(_g1->max_capacity());
562 ct_freq_note_card(_ct_bs->index_for(start));
563 #endif
565 OopsInHeapRegionClosure* oops_in_heap_closure = NULL;
566 if (check_for_refs_into_cset) {
567 // ConcurrentG1RefineThreads have worker numbers larger than what
568 // _cset_rs_update_cl[] is set up to handle. But those threads should
569 // only be active outside of a collection which means that when they
570 // reach here they should have check_for_refs_into_cset == false.
571 assert((size_t)worker_i < n_workers(), "index of worker larger than _cset_rs_update_cl[].length");
572 oops_in_heap_closure = _cset_rs_update_cl[worker_i];
573 }
574 G1UpdateRSOrPushRefOopClosure update_rs_oop_cl(_g1,
575 _g1->g1_rem_set(),
576 oops_in_heap_closure,
577 check_for_refs_into_cset,
578 worker_i);
579 update_rs_oop_cl.set_from(r);
581 G1TriggerClosure trigger_cl;
582 FilterIntoCSClosure into_cs_cl(NULL, _g1, &trigger_cl);
583 G1InvokeIfNotTriggeredClosure invoke_cl(&trigger_cl, &into_cs_cl);
584 G1Mux2Closure mux(&invoke_cl, &update_rs_oop_cl);
586 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r,
587 (check_for_refs_into_cset ?
588 (OopClosure*)&mux :
589 (OopClosure*)&update_rs_oop_cl));
591 // The region for the current card may be a young region. The
592 // current card may have been a card that was evicted from the
593 // card cache. When the card was inserted into the cache, we had
594 // determined that its region was non-young. While in the cache,
595 // the region may have been freed during a cleanup pause, reallocated
596 // and tagged as young.
597 //
598 // We wish to filter out cards for such a region but the current
599 // thread, if we're running concurrently, may "see" the young type
600 // change at any time (so an earlier "is_young" check may pass or
601 // fail arbitrarily). We tell the iteration code to perform this
602 // filtering when it has been determined that there has been an actual
603 // allocation in this region and making it safe to check the young type.
604 bool filter_young = true;
606 HeapWord* stop_point =
607 r->oops_on_card_seq_iterate_careful(dirtyRegion,
608 &filter_then_update_rs_oop_cl,
609 filter_young,
610 card_ptr);
612 // If stop_point is non-null, then we encountered an unallocated region
613 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
614 // card and re-enqueue: if we put off the card until a GC pause, then the
615 // unallocated portion will be filled in. Alternatively, we might try
616 // the full complexity of the technique used in "regular" precleaning.
617 if (stop_point != NULL) {
618 // The card might have gotten re-dirtied and re-enqueued while we
619 // worked. (In fact, it's pretty likely.)
620 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
621 *card_ptr = CardTableModRefBS::dirty_card_val();
622 MutexLockerEx x(Shared_DirtyCardQ_lock,
623 Mutex::_no_safepoint_check_flag);
624 DirtyCardQueue* sdcq =
625 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
626 sdcq->enqueue(card_ptr);
627 }
628 } else {
629 _conc_refine_cards++;
630 }
632 // This gets set to true if the card being refined has
633 // references that point into the collection set.
634 bool has_refs_into_cset = trigger_cl.triggered();
636 // We should only be detecting that the card contains references
637 // that point into the collection set if the current thread is
638 // a GC worker thread.
639 assert(!has_refs_into_cset || SafepointSynchronize::is_at_safepoint(),
640 "invalid result at non safepoint");
642 return has_refs_into_cset;
643 }
645 void G1RemSet::print_periodic_summary_info(const char* header) {
646 G1RemSetSummary current;
647 current.initialize(this);
649 _prev_period_summary.subtract_from(¤t);
650 print_summary_info(&_prev_period_summary, header);
652 _prev_period_summary.set(¤t);
653 }
655 void G1RemSet::print_summary_info() {
656 G1RemSetSummary current;
657 current.initialize(this);
659 print_summary_info(¤t, " Cumulative RS summary");
660 }
662 void G1RemSet::print_summary_info(G1RemSetSummary * summary, const char * header) {
663 assert(summary != NULL, "just checking");
665 if (header != NULL) {
666 gclog_or_tty->print_cr("%s", header);
667 }
669 #if CARD_REPEAT_HISTO
670 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
671 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
672 card_repeat_count.print_on(gclog_or_tty);
673 #endif
675 summary->print_on(gclog_or_tty);
676 }
678 void G1RemSet::prepare_for_verify() {
679 if (G1HRRSFlushLogBuffersOnVerify &&
680 (VerifyBeforeGC || VerifyAfterGC)
681 && (!_g1->full_collection() || G1VerifyRSetsDuringFullGC)) {
682 cleanupHRRS();
683 _g1->set_refine_cte_cl_concurrency(false);
684 if (SafepointSynchronize::is_at_safepoint()) {
685 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
686 dcqs.concatenate_logs();
687 }
689 G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
690 bool use_hot_card_cache = hot_card_cache->use_cache();
691 hot_card_cache->set_use_cache(false);
693 DirtyCardQueue into_cset_dcq(&_g1->into_cset_dirty_card_queue_set());
694 updateRS(&into_cset_dcq, 0);
695 _g1->into_cset_dirty_card_queue_set().clear();
697 hot_card_cache->set_use_cache(use_hot_card_cache);
698 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
699 }
700 }