Fri, 12 Jun 2009 16:20:16 -0400
6850846: G1: extend G1 marking verification
Summary: extend G1 marking verification to use either the "prev" or "next" marking information, as appropriate.
Reviewed-by: johnc, ysr
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_g1RemSet.cpp.incl"
28 #define CARD_REPEAT_HISTO 0
30 #if CARD_REPEAT_HISTO
31 static size_t ct_freq_sz;
32 static jbyte* ct_freq = NULL;
34 void init_ct_freq_table(size_t heap_sz_bytes) {
35 if (ct_freq == NULL) {
36 ct_freq_sz = heap_sz_bytes/CardTableModRefBS::card_size;
37 ct_freq = new jbyte[ct_freq_sz];
38 for (size_t j = 0; j < ct_freq_sz; j++) ct_freq[j] = 0;
39 }
40 }
42 void ct_freq_note_card(size_t index) {
43 assert(0 <= index && index < ct_freq_sz, "Bounds error.");
44 if (ct_freq[index] < 100) { ct_freq[index]++; }
45 }
47 static IntHistogram card_repeat_count(10, 10);
49 void ct_freq_update_histo_and_reset() {
50 for (size_t j = 0; j < ct_freq_sz; j++) {
51 card_repeat_count.add_entry(ct_freq[j]);
52 ct_freq[j] = 0;
53 }
55 }
56 #endif
59 class IntoCSOopClosure: public OopsInHeapRegionClosure {
60 OopsInHeapRegionClosure* _blk;
61 G1CollectedHeap* _g1;
62 public:
63 IntoCSOopClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) :
64 _g1(g1), _blk(blk) {}
65 void set_region(HeapRegion* from) {
66 _blk->set_region(from);
67 }
68 virtual void do_oop(narrowOop* p) {
69 guarantee(false, "NYI");
70 }
71 virtual void do_oop(oop* p) {
72 oop obj = *p;
73 if (_g1->obj_in_cs(obj)) _blk->do_oop(p);
74 }
75 bool apply_to_weak_ref_discovered_field() { return true; }
76 bool idempotent() { return true; }
77 };
79 class IntoCSRegionClosure: public HeapRegionClosure {
80 IntoCSOopClosure _blk;
81 G1CollectedHeap* _g1;
82 public:
83 IntoCSRegionClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) :
84 _g1(g1), _blk(g1, blk) {}
85 bool doHeapRegion(HeapRegion* r) {
86 if (!r->in_collection_set()) {
87 _blk.set_region(r);
88 if (r->isHumongous()) {
89 if (r->startsHumongous()) {
90 oop obj = oop(r->bottom());
91 obj->oop_iterate(&_blk);
92 }
93 } else {
94 r->oop_before_save_marks_iterate(&_blk);
95 }
96 }
97 return false;
98 }
99 };
101 void
102 StupidG1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
103 int worker_i) {
104 IntoCSRegionClosure rc(_g1, oc);
105 _g1->heap_region_iterate(&rc);
106 }
108 class VerifyRSCleanCardOopClosure: public OopClosure {
109 G1CollectedHeap* _g1;
110 public:
111 VerifyRSCleanCardOopClosure(G1CollectedHeap* g1) : _g1(g1) {}
113 virtual void do_oop(narrowOop* p) {
114 guarantee(false, "NYI");
115 }
116 virtual void do_oop(oop* p) {
117 oop obj = *p;
118 HeapRegion* to = _g1->heap_region_containing(obj);
119 guarantee(to == NULL || !to->in_collection_set(),
120 "Missed a rem set member.");
121 }
122 };
124 HRInto_G1RemSet::HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
125 : G1RemSet(g1), _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
126 _cg1r(g1->concurrent_g1_refine()),
127 _par_traversal_in_progress(false), _new_refs(NULL),
128 _cards_scanned(NULL), _total_cards_scanned(0)
129 {
130 _seq_task = new SubTasksDone(NumSeqTasks);
131 guarantee(n_workers() > 0, "There should be some workers");
132 _new_refs = NEW_C_HEAP_ARRAY(GrowableArray<oop*>*, n_workers());
133 for (uint i = 0; i < n_workers(); i++) {
134 _new_refs[i] = new (ResourceObj::C_HEAP) GrowableArray<oop*>(8192,true);
135 }
136 }
138 HRInto_G1RemSet::~HRInto_G1RemSet() {
139 delete _seq_task;
140 for (uint i = 0; i < n_workers(); i++) {
141 delete _new_refs[i];
142 }
143 FREE_C_HEAP_ARRAY(GrowableArray<oop*>*, _new_refs);
144 }
146 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
147 if (_g1->is_in_g1_reserved(mr.start())) {
148 _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size));
149 if (_start_first == NULL) _start_first = mr.start();
150 }
151 }
153 class ScanRSClosure : public HeapRegionClosure {
154 size_t _cards_done, _cards;
155 G1CollectedHeap* _g1h;
156 OopsInHeapRegionClosure* _oc;
157 G1BlockOffsetSharedArray* _bot_shared;
158 CardTableModRefBS *_ct_bs;
159 int _worker_i;
160 bool _try_claimed;
161 size_t _min_skip_distance, _max_skip_distance;
162 public:
163 ScanRSClosure(OopsInHeapRegionClosure* oc, int worker_i) :
164 _oc(oc),
165 _cards(0),
166 _cards_done(0),
167 _worker_i(worker_i),
168 _try_claimed(false)
169 {
170 _g1h = G1CollectedHeap::heap();
171 _bot_shared = _g1h->bot_shared();
172 _ct_bs = (CardTableModRefBS*) (_g1h->barrier_set());
173 _min_skip_distance = 16;
174 _max_skip_distance = 2 * _g1h->n_par_threads() * _min_skip_distance;
175 }
177 void set_try_claimed() { _try_claimed = true; }
179 void scanCard(size_t index, HeapRegion *r) {
180 _cards_done++;
181 DirtyCardToOopClosure* cl =
182 r->new_dcto_closure(_oc,
183 CardTableModRefBS::Precise,
184 HeapRegionDCTOC::IntoCSFilterKind);
186 // Set the "from" region in the closure.
187 _oc->set_region(r);
188 HeapWord* card_start = _bot_shared->address_for_index(index);
189 HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words;
190 Space *sp = SharedHeap::heap()->space_containing(card_start);
191 MemRegion sm_region;
192 if (ParallelGCThreads > 0) {
193 // first find the used area
194 sm_region = sp->used_region_at_save_marks();
195 } else {
196 // The closure is not idempotent. We shouldn't look at objects
197 // allocated during the GC.
198 sm_region = sp->used_region_at_save_marks();
199 }
200 MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end));
201 if (!mr.is_empty()) {
202 cl->do_MemRegion(mr);
203 }
204 }
206 void printCard(HeapRegion* card_region, size_t card_index,
207 HeapWord* card_start) {
208 gclog_or_tty->print_cr("T %d Region [" PTR_FORMAT ", " PTR_FORMAT ") "
209 "RS names card %p: "
210 "[" PTR_FORMAT ", " PTR_FORMAT ")",
211 _worker_i,
212 card_region->bottom(), card_region->end(),
213 card_index,
214 card_start, card_start + G1BlockOffsetSharedArray::N_words);
215 }
217 bool doHeapRegion(HeapRegion* r) {
218 assert(r->in_collection_set(), "should only be called on elements of CS.");
219 HeapRegionRemSet* hrrs = r->rem_set();
220 if (hrrs->iter_is_complete()) return false; // All done.
221 if (!_try_claimed && !hrrs->claim_iter()) return false;
222 _g1h->push_dirty_cards_region(r);
223 // If we didn't return above, then
224 // _try_claimed || r->claim_iter()
225 // is true: either we're supposed to work on claimed-but-not-complete
226 // regions, or we successfully claimed the region.
227 HeapRegionRemSetIterator* iter = _g1h->rem_set_iterator(_worker_i);
228 hrrs->init_iterator(iter);
229 size_t card_index;
230 size_t skip_distance = 0, current_card = 0, jump_to_card = 0;
231 while (iter->has_next(card_index)) {
232 if (current_card < jump_to_card) {
233 ++current_card;
234 continue;
235 }
236 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
237 #if 0
238 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
239 card_start, card_start + CardTableModRefBS::card_size_in_words);
240 #endif
242 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
243 assert(card_region != NULL, "Yielding cards not in the heap?");
244 _cards++;
246 if (!card_region->is_on_dirty_cards_region_list()) {
247 _g1h->push_dirty_cards_region(card_region);
248 }
250 // If the card is dirty, then we will scan it during updateRS.
251 if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) {
252 if (!_ct_bs->is_card_claimed(card_index) && _ct_bs->claim_card(card_index)) {
253 scanCard(card_index, card_region);
254 } else if (_try_claimed) {
255 if (jump_to_card == 0 || jump_to_card != current_card) {
256 // We did some useful work in the previous iteration.
257 // Decrease the distance.
258 skip_distance = MAX2(skip_distance >> 1, _min_skip_distance);
259 } else {
260 // Previous iteration resulted in a claim failure.
261 // Increase the distance.
262 skip_distance = MIN2(skip_distance << 1, _max_skip_distance);
263 }
264 jump_to_card = current_card + skip_distance;
265 }
266 }
267 ++current_card;
268 }
269 if (!_try_claimed) {
270 hrrs->set_iter_complete();
271 }
272 return false;
273 }
274 // Set all cards back to clean.
275 void cleanup() {_g1h->cleanUpCardTable();}
276 size_t cards_done() { return _cards_done;}
277 size_t cards_looked_up() { return _cards;}
278 };
280 // We want the parallel threads to start their scanning at
281 // different collection set regions to avoid contention.
282 // If we have:
283 // n collection set regions
284 // p threads
285 // Then thread t will start at region t * floor (n/p)
287 HeapRegion* HRInto_G1RemSet::calculateStartRegion(int worker_i) {
288 HeapRegion* result = _g1p->collection_set();
289 if (ParallelGCThreads > 0) {
290 size_t cs_size = _g1p->collection_set_size();
291 int n_workers = _g1->workers()->total_workers();
292 size_t cs_spans = cs_size / n_workers;
293 size_t ind = cs_spans * worker_i;
294 for (size_t i = 0; i < ind; i++)
295 result = result->next_in_collection_set();
296 }
297 return result;
298 }
300 void HRInto_G1RemSet::scanRS(OopsInHeapRegionClosure* oc, int worker_i) {
301 double rs_time_start = os::elapsedTime();
302 HeapRegion *startRegion = calculateStartRegion(worker_i);
304 BufferingOopsInHeapRegionClosure boc(oc);
305 ScanRSClosure scanRScl(&boc, worker_i);
306 _g1->collection_set_iterate_from(startRegion, &scanRScl);
307 scanRScl.set_try_claimed();
308 _g1->collection_set_iterate_from(startRegion, &scanRScl);
310 boc.done();
311 double closure_app_time_sec = boc.closure_app_seconds();
312 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) -
313 closure_app_time_sec;
314 double closure_app_time_ms = closure_app_time_sec * 1000.0;
316 assert( _cards_scanned != NULL, "invariant" );
317 _cards_scanned[worker_i] = scanRScl.cards_done();
319 _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0);
320 _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
322 double scan_new_refs_time_ms = _g1p->get_scan_new_refs_time(worker_i);
323 if (scan_new_refs_time_ms > 0.0) {
324 closure_app_time_ms += scan_new_refs_time_ms;
325 }
327 _g1p->record_obj_copy_time(worker_i, closure_app_time_ms);
328 }
330 void HRInto_G1RemSet::updateRS(int worker_i) {
331 ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
333 double start = os::elapsedTime();
334 _g1p->record_update_rs_start_time(worker_i, start * 1000.0);
336 // Apply the appropriate closure to all remaining log entries.
337 _g1->iterate_dirty_card_closure(false, worker_i);
338 // Now there should be no dirty cards.
339 if (G1RSLogCheckCardTable) {
340 CountNonCleanMemRegionClosure cl(_g1);
341 _ct_bs->mod_card_iterate(&cl);
342 // XXX This isn't true any more: keeping cards of young regions
343 // marked dirty broke it. Need some reasonable fix.
344 guarantee(cl.n() == 0, "Card table should be clean.");
345 }
347 _g1p->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
348 }
350 #ifndef PRODUCT
351 class PrintRSClosure : public HeapRegionClosure {
352 int _count;
353 public:
354 PrintRSClosure() : _count(0) {}
355 bool doHeapRegion(HeapRegion* r) {
356 HeapRegionRemSet* hrrs = r->rem_set();
357 _count += (int) hrrs->occupied();
358 if (hrrs->occupied() == 0) {
359 gclog_or_tty->print("Heap Region [" PTR_FORMAT ", " PTR_FORMAT ") "
360 "has no remset entries\n",
361 r->bottom(), r->end());
362 } else {
363 gclog_or_tty->print("Printing rem set for heap region [" PTR_FORMAT ", " PTR_FORMAT ")\n",
364 r->bottom(), r->end());
365 r->print();
366 hrrs->print();
367 gclog_or_tty->print("\nDone printing rem set\n");
368 }
369 return false;
370 }
371 int occupied() {return _count;}
372 };
373 #endif
375 class CountRSSizeClosure: public HeapRegionClosure {
376 size_t _n;
377 size_t _tot;
378 size_t _max;
379 HeapRegion* _max_r;
380 enum {
381 N = 20,
382 MIN = 6
383 };
384 int _histo[N];
385 public:
386 CountRSSizeClosure() : _n(0), _tot(0), _max(0), _max_r(NULL) {
387 for (int i = 0; i < N; i++) _histo[i] = 0;
388 }
389 bool doHeapRegion(HeapRegion* r) {
390 if (!r->continuesHumongous()) {
391 size_t occ = r->rem_set()->occupied();
392 _n++;
393 _tot += occ;
394 if (occ > _max) {
395 _max = occ;
396 _max_r = r;
397 }
398 // Fit it into a histo bin.
399 int s = 1 << MIN;
400 int i = 0;
401 while (occ > (size_t) s && i < (N-1)) {
402 s = s << 1;
403 i++;
404 }
405 _histo[i]++;
406 }
407 return false;
408 }
409 size_t n() { return _n; }
410 size_t tot() { return _tot; }
411 size_t mx() { return _max; }
412 HeapRegion* mxr() { return _max_r; }
413 void print_histo() {
414 int mx = N;
415 while (mx >= 0) {
416 if (_histo[mx-1] > 0) break;
417 mx--;
418 }
419 gclog_or_tty->print_cr("Number of regions with given RS sizes:");
420 gclog_or_tty->print_cr(" <= %8d %8d", 1 << MIN, _histo[0]);
421 for (int i = 1; i < mx-1; i++) {
422 gclog_or_tty->print_cr(" %8d - %8d %8d",
423 (1 << (MIN + i - 1)) + 1,
424 1 << (MIN + i),
425 _histo[i]);
426 }
427 gclog_or_tty->print_cr(" > %8d %8d", (1 << (MIN+mx-2))+1, _histo[mx-1]);
428 }
429 };
431 void
432 HRInto_G1RemSet::scanNewRefsRS(OopsInHeapRegionClosure* oc,
433 int worker_i) {
434 double scan_new_refs_start_sec = os::elapsedTime();
435 G1CollectedHeap* g1h = G1CollectedHeap::heap();
436 CardTableModRefBS* ct_bs = (CardTableModRefBS*) (g1h->barrier_set());
437 for (int i = 0; i < _new_refs[worker_i]->length(); i++) {
438 oop* p = _new_refs[worker_i]->at(i);
439 oop obj = *p;
440 // *p was in the collection set when p was pushed on "_new_refs", but
441 // another thread may have processed this location from an RS, so it
442 // might not point into the CS any longer. If so, it's obviously been
443 // processed, and we don't need to do anything further.
444 if (g1h->obj_in_cs(obj)) {
445 HeapRegion* r = g1h->heap_region_containing(p);
447 DEBUG_ONLY(HeapRegion* to = g1h->heap_region_containing(obj));
448 oc->set_region(r);
449 // If "p" has already been processed concurrently, this is
450 // idempotent.
451 oc->do_oop(p);
452 }
453 }
454 _g1p->record_scan_new_refs_time(worker_i,
455 (os::elapsedTime() - scan_new_refs_start_sec)
456 * 1000.0);
457 }
459 void HRInto_G1RemSet::cleanupHRRS() {
460 HeapRegionRemSet::cleanup();
461 }
463 void
464 HRInto_G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
465 int worker_i) {
466 #if CARD_REPEAT_HISTO
467 ct_freq_update_histo_and_reset();
468 #endif
469 if (worker_i == 0) {
470 _cg1r->clear_and_record_card_counts();
471 }
473 // Make this into a command-line flag...
474 if (G1RSCountHisto && (ParallelGCThreads == 0 || worker_i == 0)) {
475 CountRSSizeClosure count_cl;
476 _g1->heap_region_iterate(&count_cl);
477 gclog_or_tty->print_cr("Avg of %d RS counts is %f, max is %d, "
478 "max region is " PTR_FORMAT,
479 count_cl.n(), (float)count_cl.tot()/(float)count_cl.n(),
480 count_cl.mx(), count_cl.mxr());
481 count_cl.print_histo();
482 }
484 if (ParallelGCThreads > 0) {
485 // The two flags below were introduced temporarily to serialize
486 // the updating and scanning of remembered sets. There are some
487 // race conditions when these two operations are done in parallel
488 // and they are causing failures. When we resolve said race
489 // conditions, we'll revert back to parallel remembered set
490 // updating and scanning. See CRs 6677707 and 6677708.
491 if (G1ParallelRSetUpdatingEnabled || (worker_i == 0)) {
492 updateRS(worker_i);
493 scanNewRefsRS(oc, worker_i);
494 } else {
495 _g1p->record_update_rs_start_time(worker_i, os::elapsedTime() * 1000.0);
496 _g1p->record_update_rs_processed_buffers(worker_i, 0.0);
497 _g1p->record_update_rs_time(worker_i, 0.0);
498 _g1p->record_scan_new_refs_time(worker_i, 0.0);
499 }
500 if (G1ParallelRSetScanningEnabled || (worker_i == 0)) {
501 scanRS(oc, worker_i);
502 } else {
503 _g1p->record_scan_rs_start_time(worker_i, os::elapsedTime() * 1000.0);
504 _g1p->record_scan_rs_time(worker_i, 0.0);
505 }
506 } else {
507 assert(worker_i == 0, "invariant");
508 updateRS(0);
509 scanNewRefsRS(oc, 0);
510 scanRS(oc, 0);
511 }
512 }
514 void HRInto_G1RemSet::
515 prepare_for_oops_into_collection_set_do() {
516 #if G1_REM_SET_LOGGING
517 PrintRSClosure cl;
518 _g1->collection_set_iterate(&cl);
519 #endif
520 cleanupHRRS();
521 ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
522 _g1->set_refine_cte_cl_concurrency(false);
523 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
524 dcqs.concatenate_logs();
526 assert(!_par_traversal_in_progress, "Invariant between iterations.");
527 if (ParallelGCThreads > 0) {
528 set_par_traversal(true);
529 _seq_task->set_par_threads((int)n_workers());
530 }
531 guarantee( _cards_scanned == NULL, "invariant" );
532 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers());
533 for (uint i = 0; i < n_workers(); ++i) {
534 _cards_scanned[i] = 0;
535 }
536 _total_cards_scanned = 0;
537 }
540 class cleanUpIteratorsClosure : public HeapRegionClosure {
541 bool doHeapRegion(HeapRegion *r) {
542 HeapRegionRemSet* hrrs = r->rem_set();
543 hrrs->init_for_par_iteration();
544 return false;
545 }
546 };
548 class UpdateRSetOopsIntoCSImmediate : public OopClosure {
549 G1CollectedHeap* _g1;
550 public:
551 UpdateRSetOopsIntoCSImmediate(G1CollectedHeap* g1) : _g1(g1) { }
552 virtual void do_oop(narrowOop* p) {
553 guarantee(false, "NYI");
554 }
555 virtual void do_oop(oop* p) {
556 HeapRegion* to = _g1->heap_region_containing(*p);
557 if (to->in_collection_set()) {
558 to->rem_set()->add_reference(p, 0);
559 }
560 }
561 };
563 class UpdateRSetOopsIntoCSDeferred : public OopClosure {
564 G1CollectedHeap* _g1;
565 CardTableModRefBS* _ct_bs;
566 DirtyCardQueue* _dcq;
567 public:
568 UpdateRSetOopsIntoCSDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :
569 _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) { }
570 virtual void do_oop(narrowOop* p) {
571 guarantee(false, "NYI");
572 }
573 virtual void do_oop(oop* p) {
574 oop obj = *p;
575 if (_g1->obj_in_cs(obj)) {
576 size_t card_index = _ct_bs->index_for(p);
577 if (_ct_bs->mark_card_deferred(card_index)) {
578 _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));
579 }
580 }
581 }
582 };
584 void HRInto_G1RemSet::new_refs_iterate(OopClosure* cl) {
585 for (size_t i = 0; i < n_workers(); i++) {
586 for (int j = 0; j < _new_refs[i]->length(); j++) {
587 oop* p = _new_refs[i]->at(j);
588 cl->do_oop(p);
589 }
590 }
591 }
593 void HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do() {
594 guarantee( _cards_scanned != NULL, "invariant" );
595 _total_cards_scanned = 0;
596 for (uint i = 0; i < n_workers(); ++i)
597 _total_cards_scanned += _cards_scanned[i];
598 FREE_C_HEAP_ARRAY(size_t, _cards_scanned);
599 _cards_scanned = NULL;
600 // Cleanup after copy
601 #if G1_REM_SET_LOGGING
602 PrintRSClosure cl;
603 _g1->heap_region_iterate(&cl);
604 #endif
605 _g1->set_refine_cte_cl_concurrency(true);
606 cleanUpIteratorsClosure iterClosure;
607 _g1->collection_set_iterate(&iterClosure);
608 // Set all cards back to clean.
609 _g1->cleanUpCardTable();
611 if (ParallelGCThreads > 0) {
612 set_par_traversal(false);
613 }
615 if (_g1->evacuation_failed()) {
616 // Restore remembered sets for the regions pointing into
617 // the collection set.
618 if (G1DeferredRSUpdate) {
619 DirtyCardQueue dcq(&_g1->dirty_card_queue_set());
620 UpdateRSetOopsIntoCSDeferred deferred_update(_g1, &dcq);
621 new_refs_iterate(&deferred_update);
622 } else {
623 UpdateRSetOopsIntoCSImmediate immediate_update(_g1);
624 new_refs_iterate(&immediate_update);
625 }
626 }
627 for (uint i = 0; i < n_workers(); i++) {
628 _new_refs[i]->clear();
629 }
631 assert(!_par_traversal_in_progress, "Invariant between iterations.");
632 }
634 class UpdateRSObjectClosure: public ObjectClosure {
635 UpdateRSOopClosure* _update_rs_oop_cl;
636 public:
637 UpdateRSObjectClosure(UpdateRSOopClosure* update_rs_oop_cl) :
638 _update_rs_oop_cl(update_rs_oop_cl) {}
639 void do_object(oop obj) {
640 obj->oop_iterate(_update_rs_oop_cl);
641 }
643 };
645 class ScrubRSClosure: public HeapRegionClosure {
646 G1CollectedHeap* _g1h;
647 BitMap* _region_bm;
648 BitMap* _card_bm;
649 CardTableModRefBS* _ctbs;
650 public:
651 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
652 _g1h(G1CollectedHeap::heap()),
653 _region_bm(region_bm), _card_bm(card_bm),
654 _ctbs(NULL)
655 {
656 ModRefBarrierSet* bs = _g1h->mr_bs();
657 guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
658 _ctbs = (CardTableModRefBS*)bs;
659 }
661 bool doHeapRegion(HeapRegion* r) {
662 if (!r->continuesHumongous()) {
663 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
664 }
665 return false;
666 }
667 };
669 void HRInto_G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
670 ScrubRSClosure scrub_cl(region_bm, card_bm);
671 _g1->heap_region_iterate(&scrub_cl);
672 }
674 void HRInto_G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
675 int worker_num, int claim_val) {
676 ScrubRSClosure scrub_cl(region_bm, card_bm);
677 _g1->heap_region_par_iterate_chunked(&scrub_cl, worker_num, claim_val);
678 }
681 static IntHistogram out_of_histo(50, 50);
683 void HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {
684 // If the card is no longer dirty, nothing to do.
685 if (*card_ptr != CardTableModRefBS::dirty_card_val()) return;
687 // Construct the region representing the card.
688 HeapWord* start = _ct_bs->addr_for(card_ptr);
689 // And find the region containing it.
690 HeapRegion* r = _g1->heap_region_containing(start);
691 if (r == NULL) {
692 guarantee(_g1->is_in_permanent(start), "Or else where?");
693 return; // Not in the G1 heap (might be in perm, for example.)
694 }
695 // Why do we have to check here whether a card is on a young region,
696 // given that we dirty young regions and, as a result, the
697 // post-barrier is supposed to filter them out and never to enqueue
698 // them? When we allocate a new region as the "allocation region" we
699 // actually dirty its cards after we release the lock, since card
700 // dirtying while holding the lock was a performance bottleneck. So,
701 // as a result, it is possible for other threads to actually
702 // allocate objects in the region (after the acquire the lock)
703 // before all the cards on the region are dirtied. This is unlikely,
704 // and it doesn't happen often, but it can happen. So, the extra
705 // check below filters out those cards.
706 if (r->is_young()) {
707 return;
708 }
709 // While we are processing RSet buffers during the collection, we
710 // actually don't want to scan any cards on the collection set,
711 // since we don't want to update remebered sets with entries that
712 // point into the collection set, given that live objects from the
713 // collection set are about to move and such entries will be stale
714 // very soon. This change also deals with a reliability issue which
715 // involves scanning a card in the collection set and coming across
716 // an array that was being chunked and looking malformed. Note,
717 // however, that if evacuation fails, we have to scan any objects
718 // that were not moved and create any missing entries.
719 if (r->in_collection_set()) {
720 return;
721 }
723 // Should we defer it?
724 if (_cg1r->use_cache()) {
725 card_ptr = _cg1r->cache_insert(card_ptr);
726 // If it was not an eviction, nothing to do.
727 if (card_ptr == NULL) return;
729 // OK, we have to reset the card start, region, etc.
730 start = _ct_bs->addr_for(card_ptr);
731 r = _g1->heap_region_containing(start);
732 if (r == NULL) {
733 guarantee(_g1->is_in_permanent(start), "Or else where?");
734 return; // Not in the G1 heap (might be in perm, for example.)
735 }
736 guarantee(!r->is_young(), "It was evicted in the current minor cycle.");
737 }
739 HeapWord* end = _ct_bs->addr_for(card_ptr + 1);
740 MemRegion dirtyRegion(start, end);
742 #if CARD_REPEAT_HISTO
743 init_ct_freq_table(_g1->g1_reserved_obj_bytes());
744 ct_freq_note_card(_ct_bs->index_for(start));
745 #endif
747 UpdateRSOopClosure update_rs_oop_cl(this, worker_i);
748 update_rs_oop_cl.set_from(r);
749 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl);
751 // Undirty the card.
752 *card_ptr = CardTableModRefBS::clean_card_val();
753 // We must complete this write before we do any of the reads below.
754 OrderAccess::storeload();
755 // And process it, being careful of unallocated portions of TLAB's.
756 HeapWord* stop_point =
757 r->oops_on_card_seq_iterate_careful(dirtyRegion,
758 &filter_then_update_rs_oop_cl);
759 // If stop_point is non-null, then we encountered an unallocated region
760 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
761 // card and re-enqueue: if we put off the card until a GC pause, then the
762 // unallocated portion will be filled in. Alternatively, we might try
763 // the full complexity of the technique used in "regular" precleaning.
764 if (stop_point != NULL) {
765 // The card might have gotten re-dirtied and re-enqueued while we
766 // worked. (In fact, it's pretty likely.)
767 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
768 *card_ptr = CardTableModRefBS::dirty_card_val();
769 MutexLockerEx x(Shared_DirtyCardQ_lock,
770 Mutex::_no_safepoint_check_flag);
771 DirtyCardQueue* sdcq =
772 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
773 sdcq->enqueue(card_ptr);
774 }
775 } else {
776 out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region());
777 _conc_refine_cards++;
778 }
779 }
781 class HRRSStatsIter: public HeapRegionClosure {
782 size_t _occupied;
783 size_t _total_mem_sz;
784 size_t _max_mem_sz;
785 HeapRegion* _max_mem_sz_region;
786 public:
787 HRRSStatsIter() :
788 _occupied(0),
789 _total_mem_sz(0),
790 _max_mem_sz(0),
791 _max_mem_sz_region(NULL)
792 {}
794 bool doHeapRegion(HeapRegion* r) {
795 if (r->continuesHumongous()) return false;
796 size_t mem_sz = r->rem_set()->mem_size();
797 if (mem_sz > _max_mem_sz) {
798 _max_mem_sz = mem_sz;
799 _max_mem_sz_region = r;
800 }
801 _total_mem_sz += mem_sz;
802 size_t occ = r->rem_set()->occupied();
803 _occupied += occ;
804 return false;
805 }
806 size_t total_mem_sz() { return _total_mem_sz; }
807 size_t max_mem_sz() { return _max_mem_sz; }
808 size_t occupied() { return _occupied; }
809 HeapRegion* max_mem_sz_region() { return _max_mem_sz_region; }
810 };
812 class PrintRSThreadVTimeClosure : public ThreadClosure {
813 public:
814 virtual void do_thread(Thread *t) {
815 ConcurrentG1RefineThread* crt = (ConcurrentG1RefineThread*) t;
816 gclog_or_tty->print(" %5.2f", crt->vtime_accum());
817 }
818 };
820 void HRInto_G1RemSet::print_summary_info() {
821 G1CollectedHeap* g1 = G1CollectedHeap::heap();
823 #if CARD_REPEAT_HISTO
824 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
825 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
826 card_repeat_count.print_on(gclog_or_tty);
827 #endif
829 if (FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT) {
830 gclog_or_tty->print_cr("\nG1 rem-set out-of-region histogram: ");
831 gclog_or_tty->print_cr(" # of CS ptrs --> # of cards with that number.");
832 out_of_histo.print_on(gclog_or_tty);
833 }
834 gclog_or_tty->print_cr("\n Concurrent RS processed %d cards",
835 _conc_refine_cards);
836 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
837 jint tot_processed_buffers =
838 dcqs.processed_buffers_mut() + dcqs.processed_buffers_rs_thread();
839 gclog_or_tty->print_cr(" Of %d completed buffers:", tot_processed_buffers);
840 gclog_or_tty->print_cr(" %8d (%5.1f%%) by conc RS threads.",
841 dcqs.processed_buffers_rs_thread(),
842 100.0*(float)dcqs.processed_buffers_rs_thread()/
843 (float)tot_processed_buffers);
844 gclog_or_tty->print_cr(" %8d (%5.1f%%) by mutator threads.",
845 dcqs.processed_buffers_mut(),
846 100.0*(float)dcqs.processed_buffers_mut()/
847 (float)tot_processed_buffers);
848 gclog_or_tty->print_cr(" Conc RS threads times(s)");
849 PrintRSThreadVTimeClosure p;
850 gclog_or_tty->print(" ");
851 g1->concurrent_g1_refine()->threads_do(&p);
852 gclog_or_tty->print_cr("");
854 if (G1UseHRIntoRS) {
855 HRRSStatsIter blk;
856 g1->heap_region_iterate(&blk);
857 gclog_or_tty->print_cr(" Total heap region rem set sizes = " SIZE_FORMAT "K."
858 " Max = " SIZE_FORMAT "K.",
859 blk.total_mem_sz()/K, blk.max_mem_sz()/K);
860 gclog_or_tty->print_cr(" Static structures = " SIZE_FORMAT "K,"
861 " free_lists = " SIZE_FORMAT "K.",
862 HeapRegionRemSet::static_mem_size()/K,
863 HeapRegionRemSet::fl_mem_size()/K);
864 gclog_or_tty->print_cr(" %d occupied cards represented.",
865 blk.occupied());
866 gclog_or_tty->print_cr(" Max sz region = [" PTR_FORMAT ", " PTR_FORMAT " )"
867 ", cap = " SIZE_FORMAT "K, occ = " SIZE_FORMAT "K.",
868 blk.max_mem_sz_region()->bottom(), blk.max_mem_sz_region()->end(),
869 (blk.max_mem_sz_region()->rem_set()->mem_size() + K - 1)/K,
870 (blk.max_mem_sz_region()->rem_set()->occupied() + K - 1)/K);
871 gclog_or_tty->print_cr(" Did %d coarsenings.",
872 HeapRegionRemSet::n_coarsenings());
874 }
875 }
876 void HRInto_G1RemSet::prepare_for_verify() {
877 if (G1HRRSFlushLogBuffersOnVerify &&
878 (VerifyBeforeGC || VerifyAfterGC)
879 && !_g1->full_collection()) {
880 cleanupHRRS();
881 _g1->set_refine_cte_cl_concurrency(false);
882 if (SafepointSynchronize::is_at_safepoint()) {
883 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
884 dcqs.concatenate_logs();
885 }
886 bool cg1r_use_cache = _cg1r->use_cache();
887 _cg1r->set_use_cache(false);
888 updateRS(0);
889 _cg1r->set_use_cache(cg1r_use_cache);
891 assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
892 }
893 }