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comparison src/share/vm/gc_implementation/g1/g1RemSet.cpp @ 342:37f87013dfd8

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6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author ysr
date Thu, 05 Jun 2008 15:57:56 -0700
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children 58054a18d735
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189:0b27f3512f9e 342:37f87013dfd8
1 /*
2 * Copyright 2001-2007 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 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_g1RemSet.cpp.incl"
27
28 #define CARD_REPEAT_HISTO 0
29
30 #if CARD_REPEAT_HISTO
31 static size_t ct_freq_sz;
32 static jbyte* ct_freq = NULL;
33
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 }
41
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 }
46
47 static IntHistogram card_repeat_count(10, 10);
48
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 }
54
55 }
56 #endif
57
58
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 };
78
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 };
100
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 }
107
108 class UpdateRSOopClosure: public OopClosure {
109 HeapRegion* _from;
110 HRInto_G1RemSet* _rs;
111 int _worker_i;
112 public:
113 UpdateRSOopClosure(HRInto_G1RemSet* rs, int worker_i = 0) :
114 _from(NULL), _rs(rs), _worker_i(worker_i) {
115 guarantee(_rs != NULL, "Requires an HRIntoG1RemSet");
116 }
117
118 void set_from(HeapRegion* from) {
119 assert(from != NULL, "from region must be non-NULL");
120 _from = from;
121 }
122
123 virtual void do_oop(narrowOop* p) {
124 guarantee(false, "NYI");
125 }
126 virtual void do_oop(oop* p) {
127 assert(_from != NULL, "from region must be non-NULL");
128 _rs->par_write_ref(_from, p, _worker_i);
129 }
130 // Override: this closure is idempotent.
131 // bool idempotent() { return true; }
132 bool apply_to_weak_ref_discovered_field() { return true; }
133 };
134
135 class UpdateRSOutOfRegionClosure: public HeapRegionClosure {
136 G1CollectedHeap* _g1h;
137 ModRefBarrierSet* _mr_bs;
138 UpdateRSOopClosure _cl;
139 int _worker_i;
140 public:
141 UpdateRSOutOfRegionClosure(G1CollectedHeap* g1, int worker_i = 0) :
142 _cl(g1->g1_rem_set()->as_HRInto_G1RemSet(), worker_i),
143 _mr_bs(g1->mr_bs()),
144 _worker_i(worker_i),
145 _g1h(g1)
146 {}
147 bool doHeapRegion(HeapRegion* r) {
148 if (!r->in_collection_set() && !r->continuesHumongous()) {
149 _cl.set_from(r);
150 r->set_next_filter_kind(HeapRegionDCTOC::OutOfRegionFilterKind);
151 _mr_bs->mod_oop_in_space_iterate(r, &_cl, true, true);
152 }
153 return false;
154 }
155 };
156
157 class VerifyRSCleanCardOopClosure: public OopClosure {
158 G1CollectedHeap* _g1;
159 public:
160 VerifyRSCleanCardOopClosure(G1CollectedHeap* g1) : _g1(g1) {}
161
162 virtual void do_oop(narrowOop* p) {
163 guarantee(false, "NYI");
164 }
165 virtual void do_oop(oop* p) {
166 oop obj = *p;
167 HeapRegion* to = _g1->heap_region_containing(obj);
168 guarantee(to == NULL || !to->in_collection_set(),
169 "Missed a rem set member.");
170 }
171 };
172
173 HRInto_G1RemSet::HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
174 : G1RemSet(g1), _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
175 _cg1r(g1->concurrent_g1_refine()),
176 _par_traversal_in_progress(false), _new_refs(NULL),
177 _cards_scanned(NULL), _total_cards_scanned(0)
178 {
179 _seq_task = new SubTasksDone(NumSeqTasks);
180 _new_refs = NEW_C_HEAP_ARRAY(GrowableArray<oop*>*, ParallelGCThreads);
181 }
182
183 HRInto_G1RemSet::~HRInto_G1RemSet() {
184 delete _seq_task;
185 }
186
187 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
188 if (_g1->is_in_g1_reserved(mr.start())) {
189 _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size));
190 if (_start_first == NULL) _start_first = mr.start();
191 }
192 }
193
194 class ScanRSClosure : public HeapRegionClosure {
195 size_t _cards_done, _cards;
196 G1CollectedHeap* _g1h;
197 OopsInHeapRegionClosure* _oc;
198 G1BlockOffsetSharedArray* _bot_shared;
199 CardTableModRefBS *_ct_bs;
200 int _worker_i;
201 bool _try_claimed;
202 public:
203 ScanRSClosure(OopsInHeapRegionClosure* oc, int worker_i) :
204 _oc(oc),
205 _cards(0),
206 _cards_done(0),
207 _worker_i(worker_i),
208 _try_claimed(false)
209 {
210 _g1h = G1CollectedHeap::heap();
211 _bot_shared = _g1h->bot_shared();
212 _ct_bs = (CardTableModRefBS*) (_g1h->barrier_set());
213 }
214
215 void set_try_claimed() { _try_claimed = true; }
216
217 void scanCard(size_t index, HeapRegion *r) {
218 _cards_done++;
219 DirtyCardToOopClosure* cl =
220 r->new_dcto_closure(_oc,
221 CardTableModRefBS::Precise,
222 HeapRegionDCTOC::IntoCSFilterKind);
223
224 // Set the "from" region in the closure.
225 _oc->set_region(r);
226 HeapWord* card_start = _bot_shared->address_for_index(index);
227 HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words;
228 Space *sp = SharedHeap::heap()->space_containing(card_start);
229 MemRegion sm_region;
230 if (ParallelGCThreads > 0) {
231 // first find the used area
232 sm_region = sp->used_region_at_save_marks();
233 } else {
234 // The closure is not idempotent. We shouldn't look at objects
235 // allocated during the GC.
236 sm_region = sp->used_region_at_save_marks();
237 }
238 MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end));
239 if (!mr.is_empty()) {
240 cl->do_MemRegion(mr);
241 }
242 }
243
244 void printCard(HeapRegion* card_region, size_t card_index,
245 HeapWord* card_start) {
246 gclog_or_tty->print_cr("T %d Region [" PTR_FORMAT ", " PTR_FORMAT ") "
247 "RS names card %p: "
248 "[" PTR_FORMAT ", " PTR_FORMAT ")",
249 _worker_i,
250 card_region->bottom(), card_region->end(),
251 card_index,
252 card_start, card_start + G1BlockOffsetSharedArray::N_words);
253 }
254
255 bool doHeapRegion(HeapRegion* r) {
256 assert(r->in_collection_set(), "should only be called on elements of CS.");
257 HeapRegionRemSet* hrrs = r->rem_set();
258 if (hrrs->iter_is_complete()) return false; // All done.
259 if (!_try_claimed && !hrrs->claim_iter()) return false;
260 // If we didn't return above, then
261 // _try_claimed || r->claim_iter()
262 // is true: either we're supposed to work on claimed-but-not-complete
263 // regions, or we successfully claimed the region.
264 HeapRegionRemSetIterator* iter = _g1h->rem_set_iterator(_worker_i);
265 hrrs->init_iterator(iter);
266 size_t card_index;
267 while (iter->has_next(card_index)) {
268 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
269
270 #if 0
271 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
272 card_start, card_start + CardTableModRefBS::card_size_in_words);
273 #endif
274
275 HeapRegion* card_region = _g1h->heap_region_containing(card_start);
276 assert(card_region != NULL, "Yielding cards not in the heap?");
277 _cards++;
278
279 if (!card_region->in_collection_set()) {
280 // If the card is dirty, then we will scan it during updateRS.
281 if (!_ct_bs->is_card_claimed(card_index) &&
282 !_ct_bs->is_card_dirty(card_index)) {
283 assert(_ct_bs->is_card_clean(card_index) ||
284 _ct_bs->is_card_claimed(card_index),
285 "Card is either dirty, clean, or claimed");
286 if (_ct_bs->claim_card(card_index))
287 scanCard(card_index, card_region);
288 }
289 }
290 }
291 hrrs->set_iter_complete();
292 return false;
293 }
294 // Set all cards back to clean.
295 void cleanup() {_g1h->cleanUpCardTable();}
296 size_t cards_done() { return _cards_done;}
297 size_t cards_looked_up() { return _cards;}
298 };
299
300 // We want the parallel threads to start their scanning at
301 // different collection set regions to avoid contention.
302 // If we have:
303 // n collection set regions
304 // p threads
305 // Then thread t will start at region t * floor (n/p)
306
307 HeapRegion* HRInto_G1RemSet::calculateStartRegion(int worker_i) {
308 HeapRegion* result = _g1p->collection_set();
309 if (ParallelGCThreads > 0) {
310 size_t cs_size = _g1p->collection_set_size();
311 int n_workers = _g1->workers()->total_workers();
312 size_t cs_spans = cs_size / n_workers;
313 size_t ind = cs_spans * worker_i;
314 for (size_t i = 0; i < ind; i++)
315 result = result->next_in_collection_set();
316 }
317 return result;
318 }
319
320 void HRInto_G1RemSet::scanRS(OopsInHeapRegionClosure* oc, int worker_i) {
321 double rs_time_start = os::elapsedTime();
322 HeapRegion *startRegion = calculateStartRegion(worker_i);
323
324 BufferingOopsInHeapRegionClosure boc(oc);
325 ScanRSClosure scanRScl(&boc, worker_i);
326 _g1->collection_set_iterate_from(startRegion, &scanRScl);
327 scanRScl.set_try_claimed();
328 _g1->collection_set_iterate_from(startRegion, &scanRScl);
329
330 boc.done();
331 double closure_app_time_sec = boc.closure_app_seconds();
332 double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) -
333 closure_app_time_sec;
334 double closure_app_time_ms = closure_app_time_sec * 1000.0;
335
336 assert( _cards_scanned != NULL, "invariant" );
337 _cards_scanned[worker_i] = scanRScl.cards_done();
338
339 _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0);
340 _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
341 if (ParallelGCThreads > 0) {
342 // In this case, we called scanNewRefsRS and recorded the corresponding
343 // time.
344 double scan_new_refs_time_ms = _g1p->get_scan_new_refs_time(worker_i);
345 if (scan_new_refs_time_ms > 0.0) {
346 closure_app_time_ms += scan_new_refs_time_ms;
347 }
348 }
349 _g1p->record_obj_copy_time(worker_i, closure_app_time_ms);
350 }
351
352 void HRInto_G1RemSet::updateRS(int worker_i) {
353 ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
354
355 double start = os::elapsedTime();
356 _g1p->record_update_rs_start_time(worker_i, start * 1000.0);
357
358 if (G1RSBarrierUseQueue && !cg1r->do_traversal()) {
359 // Apply the appropriate closure to all remaining log entries.
360 _g1->iterate_dirty_card_closure(false, worker_i);
361 // Now there should be no dirty cards.
362 if (G1RSLogCheckCardTable) {
363 CountNonCleanMemRegionClosure cl(_g1);
364 _ct_bs->mod_card_iterate(&cl);
365 // XXX This isn't true any more: keeping cards of young regions
366 // marked dirty broke it. Need some reasonable fix.
367 guarantee(cl.n() == 0, "Card table should be clean.");
368 }
369 } else {
370 UpdateRSOutOfRegionClosure update_rs(_g1, worker_i);
371 _g1->heap_region_iterate(&update_rs);
372 // We did a traversal; no further one is necessary.
373 if (G1RSBarrierUseQueue) {
374 assert(cg1r->do_traversal(), "Or we shouldn't have gotten here.");
375 cg1r->set_pya_cancel();
376 }
377 if (_cg1r->use_cache()) {
378 _cg1r->clear_and_record_card_counts();
379 _cg1r->clear_hot_cache();
380 }
381 }
382 _g1p->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
383 }
384
385 #ifndef PRODUCT
386 class PrintRSClosure : public HeapRegionClosure {
387 int _count;
388 public:
389 PrintRSClosure() : _count(0) {}
390 bool doHeapRegion(HeapRegion* r) {
391 HeapRegionRemSet* hrrs = r->rem_set();
392 _count += (int) hrrs->occupied();
393 if (hrrs->occupied() == 0) {
394 gclog_or_tty->print("Heap Region [" PTR_FORMAT ", " PTR_FORMAT ") "
395 "has no remset entries\n",
396 r->bottom(), r->end());
397 } else {
398 gclog_or_tty->print("Printing rem set for heap region [" PTR_FORMAT ", " PTR_FORMAT ")\n",
399 r->bottom(), r->end());
400 r->print();
401 hrrs->print();
402 gclog_or_tty->print("\nDone printing rem set\n");
403 }
404 return false;
405 }
406 int occupied() {return _count;}
407 };
408 #endif
409
410 class CountRSSizeClosure: public HeapRegionClosure {
411 size_t _n;
412 size_t _tot;
413 size_t _max;
414 HeapRegion* _max_r;
415 enum {
416 N = 20,
417 MIN = 6
418 };
419 int _histo[N];
420 public:
421 CountRSSizeClosure() : _n(0), _tot(0), _max(0), _max_r(NULL) {
422 for (int i = 0; i < N; i++) _histo[i] = 0;
423 }
424 bool doHeapRegion(HeapRegion* r) {
425 if (!r->continuesHumongous()) {
426 size_t occ = r->rem_set()->occupied();
427 _n++;
428 _tot += occ;
429 if (occ > _max) {
430 _max = occ;
431 _max_r = r;
432 }
433 // Fit it into a histo bin.
434 int s = 1 << MIN;
435 int i = 0;
436 while (occ > (size_t) s && i < (N-1)) {
437 s = s << 1;
438 i++;
439 }
440 _histo[i]++;
441 }
442 return false;
443 }
444 size_t n() { return _n; }
445 size_t tot() { return _tot; }
446 size_t mx() { return _max; }
447 HeapRegion* mxr() { return _max_r; }
448 void print_histo() {
449 int mx = N;
450 while (mx >= 0) {
451 if (_histo[mx-1] > 0) break;
452 mx--;
453 }
454 gclog_or_tty->print_cr("Number of regions with given RS sizes:");
455 gclog_or_tty->print_cr(" <= %8d %8d", 1 << MIN, _histo[0]);
456 for (int i = 1; i < mx-1; i++) {
457 gclog_or_tty->print_cr(" %8d - %8d %8d",
458 (1 << (MIN + i - 1)) + 1,
459 1 << (MIN + i),
460 _histo[i]);
461 }
462 gclog_or_tty->print_cr(" > %8d %8d", (1 << (MIN+mx-2))+1, _histo[mx-1]);
463 }
464 };
465
466 void
467 HRInto_G1RemSet::scanNewRefsRS(OopsInHeapRegionClosure* oc,
468 int worker_i) {
469 double scan_new_refs_start_sec = os::elapsedTime();
470 G1CollectedHeap* g1h = G1CollectedHeap::heap();
471 CardTableModRefBS* ct_bs = (CardTableModRefBS*) (g1h->barrier_set());
472 while (_new_refs[worker_i]->is_nonempty()) {
473 oop* p = _new_refs[worker_i]->pop();
474 oop obj = *p;
475 // *p was in the collection set when p was pushed on "_new_refs", but
476 // another thread may have processed this location from an RS, so it
477 // might not point into the CS any longer. If so, it's obviously been
478 // processed, and we don't need to do anything further.
479 if (g1h->obj_in_cs(obj)) {
480 HeapRegion* r = g1h->heap_region_containing(p);
481
482 DEBUG_ONLY(HeapRegion* to = g1h->heap_region_containing(obj));
483 assert(ParallelGCThreads > 1
484 || to->rem_set()->contains_reference(p),
485 "Invariant: pushed after being added."
486 "(Not reliable in parallel code.)");
487 oc->set_region(r);
488 // If "p" has already been processed concurrently, this is
489 // idempotent.
490 oc->do_oop(p);
491 }
492 }
493 _g1p->record_scan_new_refs_time(worker_i,
494 (os::elapsedTime() - scan_new_refs_start_sec)
495 * 1000.0);
496 }
497
498 void HRInto_G1RemSet::set_par_traversal(bool b) {
499 _par_traversal_in_progress = b;
500 HeapRegionRemSet::set_par_traversal(b);
501 }
502
503 void HRInto_G1RemSet::cleanupHRRS() {
504 HeapRegionRemSet::cleanup();
505 }
506
507 void
508 HRInto_G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
509 int worker_i) {
510 #if CARD_REPEAT_HISTO
511 ct_freq_update_histo_and_reset();
512 #endif
513 if (worker_i == 0) {
514 _cg1r->clear_and_record_card_counts();
515 }
516
517 // Make this into a command-line flag...
518 if (G1RSCountHisto && (ParallelGCThreads == 0 || worker_i == 0)) {
519 CountRSSizeClosure count_cl;
520 _g1->heap_region_iterate(&count_cl);
521 gclog_or_tty->print_cr("Avg of %d RS counts is %f, max is %d, "
522 "max region is " PTR_FORMAT,
523 count_cl.n(), (float)count_cl.tot()/(float)count_cl.n(),
524 count_cl.mx(), count_cl.mxr());
525 count_cl.print_histo();
526 }
527
528 if (ParallelGCThreads > 0) {
529 // This is a temporary change to serialize the update and scanning
530 // of remembered sets. There are some race conditions when this is
531 // done in parallel and they are causing failures. When we resolve
532 // said race conditions, we'll revert back to parallel remembered
533 // set updating and scanning. See CRs 6677707 and 6677708.
534 if (worker_i == 0) {
535 updateRS(worker_i);
536 scanNewRefsRS(oc, worker_i);
537 scanRS(oc, worker_i);
538 }
539 } else {
540 assert(worker_i == 0, "invariant");
541
542 updateRS(0);
543 scanRS(oc, 0);
544 }
545 }
546
547 void HRInto_G1RemSet::
548 prepare_for_oops_into_collection_set_do() {
549 #if G1_REM_SET_LOGGING
550 PrintRSClosure cl;
551 _g1->collection_set_iterate(&cl);
552 #endif
553 cleanupHRRS();
554 ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
555 _g1->set_refine_cte_cl_concurrency(false);
556 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
557 dcqs.concatenate_logs();
558
559 assert(!_par_traversal_in_progress, "Invariant between iterations.");
560 if (ParallelGCThreads > 0) {
561 set_par_traversal(true);
562 int n_workers = _g1->workers()->total_workers();
563 _seq_task->set_par_threads(n_workers);
564 for (uint i = 0; i < ParallelGCThreads; i++)
565 _new_refs[i] = new (ResourceObj::C_HEAP) GrowableArray<oop*>(8192,true);
566
567 if (cg1r->do_traversal()) {
568 updateRS(0);
569 // Have to do this again after updaters
570 cleanupHRRS();
571 }
572 }
573 guarantee( _cards_scanned == NULL, "invariant" );
574 _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers());
575 _total_cards_scanned = 0;
576 }
577
578
579 class cleanUpIteratorsClosure : public HeapRegionClosure {
580 bool doHeapRegion(HeapRegion *r) {
581 HeapRegionRemSet* hrrs = r->rem_set();
582 hrrs->init_for_par_iteration();
583 return false;
584 }
585 };
586
587 void HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do() {
588 guarantee( _cards_scanned != NULL, "invariant" );
589 _total_cards_scanned = 0;
590 for (uint i = 0; i < n_workers(); ++i)
591 _total_cards_scanned += _cards_scanned[i];
592 FREE_C_HEAP_ARRAY(size_t, _cards_scanned);
593 _cards_scanned = NULL;
594 // Cleanup after copy
595 #if G1_REM_SET_LOGGING
596 PrintRSClosure cl;
597 _g1->heap_region_iterate(&cl);
598 #endif
599 _g1->set_refine_cte_cl_concurrency(true);
600 cleanUpIteratorsClosure iterClosure;
601 _g1->collection_set_iterate(&iterClosure);
602 // Set all cards back to clean.
603 _g1->cleanUpCardTable();
604 if (ParallelGCThreads > 0) {
605 ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
606 if (cg1r->do_traversal()) {
607 cg1r->cg1rThread()->set_do_traversal(false);
608 }
609 for (uint i = 0; i < ParallelGCThreads; i++) {
610 delete _new_refs[i];
611 }
612 set_par_traversal(false);
613 }
614 assert(!_par_traversal_in_progress, "Invariant between iterations.");
615 }
616
617 class UpdateRSObjectClosure: public ObjectClosure {
618 UpdateRSOopClosure* _update_rs_oop_cl;
619 public:
620 UpdateRSObjectClosure(UpdateRSOopClosure* update_rs_oop_cl) :
621 _update_rs_oop_cl(update_rs_oop_cl) {}
622 void do_object(oop obj) {
623 obj->oop_iterate(_update_rs_oop_cl);
624 }
625
626 };
627
628 class ScrubRSClosure: public HeapRegionClosure {
629 G1CollectedHeap* _g1h;
630 BitMap* _region_bm;
631 BitMap* _card_bm;
632 CardTableModRefBS* _ctbs;
633 public:
634 ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
635 _g1h(G1CollectedHeap::heap()),
636 _region_bm(region_bm), _card_bm(card_bm),
637 _ctbs(NULL)
638 {
639 ModRefBarrierSet* bs = _g1h->mr_bs();
640 guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
641 _ctbs = (CardTableModRefBS*)bs;
642 }
643
644 bool doHeapRegion(HeapRegion* r) {
645 if (!r->continuesHumongous()) {
646 r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
647 }
648 return false;
649 }
650 };
651
652 void HRInto_G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
653 ScrubRSClosure scrub_cl(region_bm, card_bm);
654 _g1->heap_region_iterate(&scrub_cl);
655 }
656
657 void HRInto_G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
658 int worker_num, int claim_val) {
659 ScrubRSClosure scrub_cl(region_bm, card_bm);
660 _g1->heap_region_par_iterate_chunked(&scrub_cl, worker_num, claim_val);
661 }
662
663
664 class ConcRefineRegionClosure: public HeapRegionClosure {
665 G1CollectedHeap* _g1h;
666 CardTableModRefBS* _ctbs;
667 ConcurrentGCThread* _cgc_thrd;
668 ConcurrentG1Refine* _cg1r;
669 unsigned _cards_processed;
670 UpdateRSOopClosure _update_rs_oop_cl;
671 public:
672 ConcRefineRegionClosure(CardTableModRefBS* ctbs,
673 ConcurrentG1Refine* cg1r,
674 HRInto_G1RemSet* g1rs) :
675 _ctbs(ctbs), _cg1r(cg1r), _cgc_thrd(cg1r->cg1rThread()),
676 _update_rs_oop_cl(g1rs), _cards_processed(0),
677 _g1h(G1CollectedHeap::heap())
678 {}
679
680 bool doHeapRegion(HeapRegion* r) {
681 if (!r->in_collection_set() &&
682 !r->continuesHumongous() &&
683 !r->is_young()) {
684 _update_rs_oop_cl.set_from(r);
685 UpdateRSObjectClosure update_rs_obj_cl(&_update_rs_oop_cl);
686
687 // For each run of dirty card in the region:
688 // 1) Clear the cards.
689 // 2) Process the range corresponding to the run, adding any
690 // necessary RS entries.
691 // 1 must precede 2, so that a concurrent modification redirties the
692 // card. If a processing attempt does not succeed, because it runs
693 // into an unparseable region, we will do binary search to find the
694 // beginning of the next parseable region.
695 HeapWord* startAddr = r->bottom();
696 HeapWord* endAddr = r->used_region().end();
697 HeapWord* lastAddr;
698 HeapWord* nextAddr;
699
700 for (nextAddr = lastAddr = startAddr;
701 nextAddr < endAddr;
702 nextAddr = lastAddr) {
703 MemRegion dirtyRegion;
704
705 // Get and clear dirty region from card table
706 MemRegion next_mr(nextAddr, endAddr);
707 dirtyRegion =
708 _ctbs->dirty_card_range_after_reset(
709 next_mr,
710 true, CardTableModRefBS::clean_card_val());
711 assert(dirtyRegion.start() >= nextAddr,
712 "returned region inconsistent?");
713
714 if (!dirtyRegion.is_empty()) {
715 HeapWord* stop_point =
716 r->object_iterate_mem_careful(dirtyRegion,
717 &update_rs_obj_cl);
718 if (stop_point == NULL) {
719 lastAddr = dirtyRegion.end();
720 _cards_processed +=
721 (int) (dirtyRegion.word_size() / CardTableModRefBS::card_size_in_words);
722 } else {
723 // We're going to skip one or more cards that we can't parse.
724 HeapWord* next_parseable_card =
725 r->next_block_start_careful(stop_point);
726 // Round this up to a card boundary.
727 next_parseable_card =
728 _ctbs->addr_for(_ctbs->byte_after_const(next_parseable_card));
729 // Now we invalidate the intervening cards so we'll see them
730 // again.
731 MemRegion remaining_dirty =
732 MemRegion(stop_point, dirtyRegion.end());
733 MemRegion skipped =
734 MemRegion(stop_point, next_parseable_card);
735 _ctbs->invalidate(skipped.intersection(remaining_dirty));
736
737 // Now start up again where we can parse.
738 lastAddr = next_parseable_card;
739
740 // Count how many we did completely.
741 _cards_processed +=
742 (stop_point - dirtyRegion.start()) /
743 CardTableModRefBS::card_size_in_words;
744 }
745 // Allow interruption at regular intervals.
746 // (Might need to make them more regular, if we get big
747 // dirty regions.)
748 if (_cgc_thrd != NULL) {
749 if (_cgc_thrd->should_yield()) {
750 _cgc_thrd->yield();
751 switch (_cg1r->get_pya()) {
752 case PYA_continue:
753 // This may have changed: re-read.
754 endAddr = r->used_region().end();
755 continue;
756 case PYA_restart: case PYA_cancel:
757 return true;
758 }
759 }
760 }
761 } else {
762 break;
763 }
764 }
765 }
766 // A good yield opportunity.
767 if (_cgc_thrd != NULL) {
768 if (_cgc_thrd->should_yield()) {
769 _cgc_thrd->yield();
770 switch (_cg1r->get_pya()) {
771 case PYA_restart: case PYA_cancel:
772 return true;
773 default:
774 break;
775 }
776
777 }
778 }
779 return false;
780 }
781
782 unsigned cards_processed() { return _cards_processed; }
783 };
784
785
786 void HRInto_G1RemSet::concurrentRefinementPass(ConcurrentG1Refine* cg1r) {
787 ConcRefineRegionClosure cr_cl(ct_bs(), cg1r, this);
788 _g1->heap_region_iterate(&cr_cl);
789 _conc_refine_traversals++;
790 _conc_refine_cards += cr_cl.cards_processed();
791 }
792
793 static IntHistogram out_of_histo(50, 50);
794
795
796
797 void HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {
798 // If the card is no longer dirty, nothing to do.
799 if (*card_ptr != CardTableModRefBS::dirty_card_val()) return;
800
801 // Construct the region representing the card.
802 HeapWord* start = _ct_bs->addr_for(card_ptr);
803 // And find the region containing it.
804 HeapRegion* r = _g1->heap_region_containing(start);
805 if (r == NULL) {
806 guarantee(_g1->is_in_permanent(start), "Or else where?");
807 return; // Not in the G1 heap (might be in perm, for example.)
808 }
809 // Why do we have to check here whether a card is on a young region,
810 // given that we dirty young regions and, as a result, the
811 // post-barrier is supposed to filter them out and never to enqueue
812 // them? When we allocate a new region as the "allocation region" we
813 // actually dirty its cards after we release the lock, since card
814 // dirtying while holding the lock was a performance bottleneck. So,
815 // as a result, it is possible for other threads to actually
816 // allocate objects in the region (after the acquire the lock)
817 // before all the cards on the region are dirtied. This is unlikely,
818 // and it doesn't happen often, but it can happen. So, the extra
819 // check below filters out those cards.
820 if (r->is_young()) {
821 return;
822 }
823 // While we are processing RSet buffers during the collection, we
824 // actually don't want to scan any cards on the collection set,
825 // since we don't want to update remebered sets with entries that
826 // point into the collection set, given that live objects from the
827 // collection set are about to move and such entries will be stale
828 // very soon. This change also deals with a reliability issue which
829 // involves scanning a card in the collection set and coming across
830 // an array that was being chunked and looking malformed. Note,
831 // however, that if evacuation fails, we have to scan any objects
832 // that were not moved and create any missing entries.
833 if (r->in_collection_set()) {
834 return;
835 }
836
837 // Should we defer it?
838 if (_cg1r->use_cache()) {
839 card_ptr = _cg1r->cache_insert(card_ptr);
840 // If it was not an eviction, nothing to do.
841 if (card_ptr == NULL) return;
842
843 // OK, we have to reset the card start, region, etc.
844 start = _ct_bs->addr_for(card_ptr);
845 r = _g1->heap_region_containing(start);
846 if (r == NULL) {
847 guarantee(_g1->is_in_permanent(start), "Or else where?");
848 return; // Not in the G1 heap (might be in perm, for example.)
849 }
850 guarantee(!r->is_young(), "It was evicted in the current minor cycle.");
851 }
852
853 HeapWord* end = _ct_bs->addr_for(card_ptr + 1);
854 MemRegion dirtyRegion(start, end);
855
856 #if CARD_REPEAT_HISTO
857 init_ct_freq_table(_g1->g1_reserved_obj_bytes());
858 ct_freq_note_card(_ct_bs->index_for(start));
859 #endif
860
861 UpdateRSOopClosure update_rs_oop_cl(this, worker_i);
862 update_rs_oop_cl.set_from(r);
863 FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl);
864
865 // Undirty the card.
866 *card_ptr = CardTableModRefBS::clean_card_val();
867 // We must complete this write before we do any of the reads below.
868 OrderAccess::storeload();
869 // And process it, being careful of unallocated portions of TLAB's.
870 HeapWord* stop_point =
871 r->oops_on_card_seq_iterate_careful(dirtyRegion,
872 &filter_then_update_rs_oop_cl);
873 // If stop_point is non-null, then we encountered an unallocated region
874 // (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
875 // card and re-enqueue: if we put off the card until a GC pause, then the
876 // unallocated portion will be filled in. Alternatively, we might try
877 // the full complexity of the technique used in "regular" precleaning.
878 if (stop_point != NULL) {
879 // The card might have gotten re-dirtied and re-enqueued while we
880 // worked. (In fact, it's pretty likely.)
881 if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
882 *card_ptr = CardTableModRefBS::dirty_card_val();
883 MutexLockerEx x(Shared_DirtyCardQ_lock,
884 Mutex::_no_safepoint_check_flag);
885 DirtyCardQueue* sdcq =
886 JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
887 sdcq->enqueue(card_ptr);
888 }
889 } else {
890 out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region());
891 _conc_refine_cards++;
892 }
893 }
894
895 class HRRSStatsIter: public HeapRegionClosure {
896 size_t _occupied;
897 size_t _total_mem_sz;
898 size_t _max_mem_sz;
899 HeapRegion* _max_mem_sz_region;
900 public:
901 HRRSStatsIter() :
902 _occupied(0),
903 _total_mem_sz(0),
904 _max_mem_sz(0),
905 _max_mem_sz_region(NULL)
906 {}
907
908 bool doHeapRegion(HeapRegion* r) {
909 if (r->continuesHumongous()) return false;
910 size_t mem_sz = r->rem_set()->mem_size();
911 if (mem_sz > _max_mem_sz) {
912 _max_mem_sz = mem_sz;
913 _max_mem_sz_region = r;
914 }
915 _total_mem_sz += mem_sz;
916 size_t occ = r->rem_set()->occupied();
917 _occupied += occ;
918 return false;
919 }
920 size_t total_mem_sz() { return _total_mem_sz; }
921 size_t max_mem_sz() { return _max_mem_sz; }
922 size_t occupied() { return _occupied; }
923 HeapRegion* max_mem_sz_region() { return _max_mem_sz_region; }
924 };
925
926 void HRInto_G1RemSet::print_summary_info() {
927 G1CollectedHeap* g1 = G1CollectedHeap::heap();
928 ConcurrentG1RefineThread* cg1r_thrd =
929 g1->concurrent_g1_refine()->cg1rThread();
930
931 #if CARD_REPEAT_HISTO
932 gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
933 gclog_or_tty->print_cr(" # of repeats --> # of cards with that number.");
934 card_repeat_count.print_on(gclog_or_tty);
935 #endif
936
937 if (FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT) {
938 gclog_or_tty->print_cr("\nG1 rem-set out-of-region histogram: ");
939 gclog_or_tty->print_cr(" # of CS ptrs --> # of cards with that number.");
940 out_of_histo.print_on(gclog_or_tty);
941 }
942 gclog_or_tty->print_cr("\n Concurrent RS processed %d cards in "
943 "%5.2fs.",
944 _conc_refine_cards, cg1r_thrd->vtime_accum());
945
946 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
947 jint tot_processed_buffers =
948 dcqs.processed_buffers_mut() + dcqs.processed_buffers_rs_thread();
949 gclog_or_tty->print_cr(" Of %d completed buffers:", tot_processed_buffers);
950 gclog_or_tty->print_cr(" %8d (%5.1f%%) by conc RS thread.",
951 dcqs.processed_buffers_rs_thread(),
952 100.0*(float)dcqs.processed_buffers_rs_thread()/
953 (float)tot_processed_buffers);
954 gclog_or_tty->print_cr(" %8d (%5.1f%%) by mutator threads.",
955 dcqs.processed_buffers_mut(),
956 100.0*(float)dcqs.processed_buffers_mut()/
957 (float)tot_processed_buffers);
958 gclog_or_tty->print_cr(" Did %d concurrent refinement traversals.",
959 _conc_refine_traversals);
960 if (!G1RSBarrierUseQueue) {
961 gclog_or_tty->print_cr(" Scanned %8.2f cards/traversal.",
962 _conc_refine_traversals > 0 ?
963 (float)_conc_refine_cards/(float)_conc_refine_traversals :
964 0);
965 }
966 gclog_or_tty->print_cr("");
967 if (G1UseHRIntoRS) {
968 HRRSStatsIter blk;
969 g1->heap_region_iterate(&blk);
970 gclog_or_tty->print_cr(" Total heap region rem set sizes = " SIZE_FORMAT "K."
971 " Max = " SIZE_FORMAT "K.",
972 blk.total_mem_sz()/K, blk.max_mem_sz()/K);
973 gclog_or_tty->print_cr(" Static structures = " SIZE_FORMAT "K,"
974 " free_lists = " SIZE_FORMAT "K.",
975 HeapRegionRemSet::static_mem_size()/K,
976 HeapRegionRemSet::fl_mem_size()/K);
977 gclog_or_tty->print_cr(" %d occupied cards represented.",
978 blk.occupied());
979 gclog_or_tty->print_cr(" Max sz region = [" PTR_FORMAT ", " PTR_FORMAT " )"
980 " %s, cap = " SIZE_FORMAT "K, occ = " SIZE_FORMAT "K.",
981 blk.max_mem_sz_region()->bottom(), blk.max_mem_sz_region()->end(),
982 (blk.max_mem_sz_region()->popular() ? "POP" : ""),
983 (blk.max_mem_sz_region()->rem_set()->mem_size() + K - 1)/K,
984 (blk.max_mem_sz_region()->rem_set()->occupied() + K - 1)/K);
985 gclog_or_tty->print_cr(" Did %d coarsenings.",
986 HeapRegionRemSet::n_coarsenings());
987
988 }
989 }
990 void HRInto_G1RemSet::prepare_for_verify() {
991 if (G1HRRSFlushLogBuffersOnVerify && VerifyBeforeGC && !_g1->full_collection()) {
992 cleanupHRRS();
993 _g1->set_refine_cte_cl_concurrency(false);
994 if (SafepointSynchronize::is_at_safepoint()) {
995 DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
996 dcqs.concatenate_logs();
997 }
998 bool cg1r_use_cache = _cg1r->use_cache();
999 _cg1r->set_use_cache(false);
1000 updateRS(0);
1001 _cg1r->set_use_cache(cg1r_use_cache);
1002 }
1003 }