1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
29 #include "gc_implementation/g1/heapRegion.inline.hpp"
30 #include "gc_implementation/g1/heapRegionRemSet.hpp"
31 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
32 #include "memory/genOopClosures.inline.hpp"
33 #include "memory/iterator.hpp"
34 #include "oops/oop.inline.hpp"
35
36 int HeapRegion::LogOfHRGrainBytes = 0;
37 int HeapRegion::LogOfHRGrainWords = 0;
38 size_t HeapRegion::GrainBytes = 0;
39 size_t HeapRegion::GrainWords = 0;
40 size_t HeapRegion::CardsPerRegion = 0;
41
42 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
43 HeapRegion* hr, ExtendedOopClosure* cl,
44 CardTableModRefBS::PrecisionStyle precision,
45 FilterKind fk) :
46 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
47 _hr(hr), _fk(fk), _g1(g1) { }
48
49 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
50 OopClosure* oc) :
51 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
52
53 template<class ClosureType>
54 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
55 HeapRegion* hr,
56 HeapWord* cur, HeapWord* top) {
57 oop cur_oop = oop(cur);
58 int oop_size = cur_oop->size();
59 HeapWord* next_obj = cur + oop_size;
60 while (next_obj < top) {
61 // Keep filtering the remembered set.
62 if (!g1h->is_obj_dead(cur_oop, hr)) {
63 // Bottom lies entirely below top, so we can call the
64 // non-memRegion version of oop_iterate below.
65 cur_oop->oop_iterate(cl);
66 }
67 cur = next_obj;
68 cur_oop = oop(cur);
69 oop_size = cur_oop->size();
70 next_obj = cur + oop_size;
71 }
72 return cur;
73 }
74
75 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
76 HeapWord* bottom,
77 HeapWord* top,
78 ExtendedOopClosure* cl) {
79 G1CollectedHeap* g1h = _g1;
80 int oop_size;
81 ExtendedOopClosure* cl2 = NULL;
82
83 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
84 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
85
86 switch (_fk) {
87 case NoFilterKind: cl2 = cl; break;
88 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
89 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
90 default: ShouldNotReachHere();
91 }
92
93 // Start filtering what we add to the remembered set. If the object is
94 // not considered dead, either because it is marked (in the mark bitmap)
95 // or it was allocated after marking finished, then we add it. Otherwise
96 // we can safely ignore the object.
97 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
98 oop_size = oop(bottom)->oop_iterate(cl2, mr);
99 } else {
100 oop_size = oop(bottom)->size();
101 }
102
103 bottom += oop_size;
104
105 if (bottom < top) {
106 // We replicate the loop below for several kinds of possible filters.
107 switch (_fk) {
108 case NoFilterKind:
109 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
110 break;
111
112 case IntoCSFilterKind: {
113 FilterIntoCSClosure filt(this, g1h, cl);
114 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
115 break;
116 }
117
118 case OutOfRegionFilterKind: {
119 FilterOutOfRegionClosure filt(_hr, cl);
120 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
121 break;
122 }
123
124 default:
125 ShouldNotReachHere();
126 }
127
128 // Last object. Need to do dead-obj filtering here too.
129 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
130 oop(bottom)->oop_iterate(cl2, mr);
131 }
132 }
133 }
134
135 // Minimum region size; we won't go lower than that.
136 // We might want to decrease this in the future, to deal with small
137 // heaps a bit more efficiently.
138 #define MIN_REGION_SIZE ( 1024 * 1024 )
139
140 // Maximum region size; we don't go higher than that. There's a good
141 // reason for having an upper bound. We don't want regions to get too
142 // large, otherwise cleanup's effectiveness would decrease as there
143 // will be fewer opportunities to find totally empty regions after
144 // marking.
145 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
146
147 // The automatic region size calculation will try to have around this
148 // many regions in the heap (based on the min heap size).
149 #define TARGET_REGION_NUMBER 2048
150
151 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
152 // region_size in bytes
153 uintx region_size = G1HeapRegionSize;
154 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
155 // We base the automatic calculation on the min heap size. This
156 // can be problematic if the spread between min and max is quite
157 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
158 // the max size, the region size might be way too large for the
159 // min size. Either way, some users might have to set the region
160 // size manually for some -Xms / -Xmx combos.
161
162 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
163 (uintx) MIN_REGION_SIZE);
164 }
165
166 int region_size_log = log2_long((jlong) region_size);
167 // Recalculate the region size to make sure it's a power of
168 // 2. This means that region_size is the largest power of 2 that's
169 // <= what we've calculated so far.
170 region_size = ((uintx)1 << region_size_log);
171
172 // Now make sure that we don't go over or under our limits.
173 if (region_size < MIN_REGION_SIZE) {
174 region_size = MIN_REGION_SIZE;
175 } else if (region_size > MAX_REGION_SIZE) {
176 region_size = MAX_REGION_SIZE;
177 }
178
179 // And recalculate the log.
180 region_size_log = log2_long((jlong) region_size);
181
182 // Now, set up the globals.
183 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
184 LogOfHRGrainBytes = region_size_log;
185
186 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
187 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
188
189 guarantee(GrainBytes == 0, "we should only set it once");
190 // The cast to int is safe, given that we've bounded region_size by
191 // MIN_REGION_SIZE and MAX_REGION_SIZE.
192 GrainBytes = (size_t)region_size;
193
194 guarantee(GrainWords == 0, "we should only set it once");
195 GrainWords = GrainBytes >> LogHeapWordSize;
196 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
197
198 guarantee(CardsPerRegion == 0, "we should only set it once");
199 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
200 }
201
202 void HeapRegion::reset_after_compaction() {
203 G1OffsetTableContigSpace::reset_after_compaction();
204 // After a compaction the mark bitmap is invalid, so we must
205 // treat all objects as being inside the unmarked area.
206 zero_marked_bytes();
207 init_top_at_mark_start();
208 }
209
210 void HeapRegion::hr_clear(bool par, bool clear_space) {
211 assert(_humongous_type == NotHumongous,
212 "we should have already filtered out humongous regions");
213 assert(_humongous_start_region == NULL,
214 "we should have already filtered out humongous regions");
215 assert(_end == _orig_end,
216 "we should have already filtered out humongous regions");
217
218 _in_collection_set = false;
219
220 set_young_index_in_cset(-1);
221 uninstall_surv_rate_group();
222 set_young_type(NotYoung);
223 reset_pre_dummy_top();
224
225 if (!par) {
226 // If this is parallel, this will be done later.
227 HeapRegionRemSet* hrrs = rem_set();
228 if (hrrs != NULL) hrrs->clear();
229 _claimed = InitialClaimValue;
230 }
231 zero_marked_bytes();
232
233 _offsets.resize(HeapRegion::GrainWords);
234 init_top_at_mark_start();
235 if (clear_space) clear(SpaceDecorator::Mangle);
236 }
237
238 void HeapRegion::par_clear() {
239 assert(used() == 0, "the region should have been already cleared");
240 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
241 HeapRegionRemSet* hrrs = rem_set();
242 hrrs->clear();
243 CardTableModRefBS* ct_bs =
244 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
245 ct_bs->clear(MemRegion(bottom(), end()));
246 }
247
248 void HeapRegion::calc_gc_efficiency() {
249 // GC efficiency is the ratio of how much space would be
250 // reclaimed over how long we predict it would take to reclaim it.
251 G1CollectedHeap* g1h = G1CollectedHeap::heap();
252 G1CollectorPolicy* g1p = g1h->g1_policy();
253
254 // Retrieve a prediction of the elapsed time for this region for
255 // a mixed gc because the region will only be evacuated during a
256 // mixed gc.
257 double region_elapsed_time_ms =
258 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
259 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
260 }
261
262 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
263 assert(!isHumongous(), "sanity / pre-condition");
264 assert(end() == _orig_end,
265 "Should be normal before the humongous object allocation");
266 assert(top() == bottom(), "should be empty");
267 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
268
269 _humongous_type = StartsHumongous;
270 _humongous_start_region = this;
271
272 set_end(new_end);
273 _offsets.set_for_starts_humongous(new_top);
274 }
275
276 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
277 assert(!isHumongous(), "sanity / pre-condition");
278 assert(end() == _orig_end,
279 "Should be normal before the humongous object allocation");
280 assert(top() == bottom(), "should be empty");
281 assert(first_hr->startsHumongous(), "pre-condition");
282
283 _humongous_type = ContinuesHumongous;
284 _humongous_start_region = first_hr;
285 }
286
287 void HeapRegion::set_notHumongous() {
288 assert(isHumongous(), "pre-condition");
289
290 if (startsHumongous()) {
291 assert(top() <= end(), "pre-condition");
292 set_end(_orig_end);
293 if (top() > end()) {
294 // at least one "continues humongous" region after it
295 set_top(end());
296 }
297 } else {
298 // continues humongous
299 assert(end() == _orig_end, "sanity");
300 }
301
302 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
303 _humongous_type = NotHumongous;
304 _humongous_start_region = NULL;
305 }
306
307 bool HeapRegion::claimHeapRegion(jint claimValue) {
308 jint current = _claimed;
309 if (current != claimValue) {
310 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
311 if (res == current) {
312 return true;
313 }
314 }
315 return false;
316 }
317
318 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
319 HeapWord* low = addr;
320 HeapWord* high = end();
321 while (low < high) {
322 size_t diff = pointer_delta(high, low);
323 // Must add one below to bias toward the high amount. Otherwise, if
324 // "high" were at the desired value, and "low" were one less, we
325 // would not converge on "high". This is not symmetric, because
326 // we set "high" to a block start, which might be the right one,
327 // which we don't do for "low".
328 HeapWord* middle = low + (diff+1)/2;
329 if (middle == high) return high;
330 HeapWord* mid_bs = block_start_careful(middle);
331 if (mid_bs < addr) {
332 low = middle;
333 } else {
334 high = mid_bs;
335 }
336 }
337 assert(low == high && low >= addr, "Didn't work.");
338 return low;
339 }
340
341 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
342 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
343 #endif // _MSC_VER
344
345
346 HeapRegion::HeapRegion(uint hrs_index,
347 G1BlockOffsetSharedArray* sharedOffsetArray,
348 MemRegion mr) :
349 G1OffsetTableContigSpace(sharedOffsetArray, mr),
350 _hrs_index(hrs_index),
351 _humongous_type(NotHumongous), _humongous_start_region(NULL),
352 _in_collection_set(false),
353 _next_in_special_set(NULL), _orig_end(NULL),
354 _claimed(InitialClaimValue), _evacuation_failed(false),
355 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
356 _young_type(NotYoung), _next_young_region(NULL),
357 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
358 #ifdef ASSERT
359 _containing_set(NULL),
360 #endif // ASSERT
361 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
362 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
363 _predicted_bytes_to_copy(0)
364 {
365 _orig_end = mr.end();
366 // Note that initialize() will set the start of the unmarked area of the
367 // region.
368 hr_clear(false /*par*/, false /*clear_space*/);
369 set_top(bottom());
370 set_saved_mark();
371
372 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
373
374 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
375 }
376
377 CompactibleSpace* HeapRegion::next_compaction_space() const {
378 // We're not using an iterator given that it will wrap around when
379 // it reaches the last region and this is not what we want here.
380 G1CollectedHeap* g1h = G1CollectedHeap::heap();
381 uint index = hrs_index() + 1;
382 while (index < g1h->n_regions()) {
383 HeapRegion* hr = g1h->region_at(index);
384 if (!hr->isHumongous()) {
385 return hr;
386 }
387 index += 1;
388 }
389 return NULL;
390 }
391
392 void HeapRegion::save_marks() {
393 set_saved_mark();
394 }
395
396 void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
397 HeapWord* p = mr.start();
398 HeapWord* e = mr.end();
399 oop obj;
400 while (p < e) {
401 obj = oop(p);
402 p += obj->oop_iterate(cl);
403 }
404 assert(p == e, "bad memregion: doesn't end on obj boundary");
405 }
406
407 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
408 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
409 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
410 }
411 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
412
413
414 void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
415 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
416 }
417
418 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
419 bool during_conc_mark) {
420 // We always recreate the prev marking info and we'll explicitly
421 // mark all objects we find to be self-forwarded on the prev
422 // bitmap. So all objects need to be below PTAMS.
423 _prev_top_at_mark_start = top();
424 _prev_marked_bytes = 0;
425
426 if (during_initial_mark) {
427 // During initial-mark, we'll also explicitly mark all objects
428 // we find to be self-forwarded on the next bitmap. So all
429 // objects need to be below NTAMS.
430 _next_top_at_mark_start = top();
431 _next_marked_bytes = 0;
432 } else if (during_conc_mark) {
433 // During concurrent mark, all objects in the CSet (including
434 // the ones we find to be self-forwarded) are implicitly live.
435 // So all objects need to be above NTAMS.
436 _next_top_at_mark_start = bottom();
437 _next_marked_bytes = 0;
438 }
439 }
440
441 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
442 bool during_conc_mark,
443 size_t marked_bytes) {
444 assert(0 <= marked_bytes && marked_bytes <= used(),
445 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
446 marked_bytes, used()));
447 _prev_marked_bytes = marked_bytes;
448 }
449
450 HeapWord*
451 HeapRegion::object_iterate_mem_careful(MemRegion mr,
452 ObjectClosure* cl) {
453 G1CollectedHeap* g1h = G1CollectedHeap::heap();
454 // We used to use "block_start_careful" here. But we're actually happy
455 // to update the BOT while we do this...
456 HeapWord* cur = block_start(mr.start());
457 mr = mr.intersection(used_region());
458 if (mr.is_empty()) return NULL;
459 // Otherwise, find the obj that extends onto mr.start().
460
461 assert(cur <= mr.start()
462 && (oop(cur)->klass_or_null() == NULL ||
463 cur + oop(cur)->size() > mr.start()),
464 "postcondition of block_start");
465 oop obj;
466 while (cur < mr.end()) {
467 obj = oop(cur);
468 if (obj->klass_or_null() == NULL) {
469 // Ran into an unparseable point.
470 return cur;
471 } else if (!g1h->is_obj_dead(obj)) {
472 cl->do_object(obj);
473 }
474 if (cl->abort()) return cur;
475 // The check above must occur before the operation below, since an
476 // abort might invalidate the "size" operation.
477 cur += obj->size();
478 }
479 return NULL;
480 }
481
482 HeapWord*
483 HeapRegion::
484 oops_on_card_seq_iterate_careful(MemRegion mr,
485 FilterOutOfRegionClosure* cl,
486 bool filter_young,
487 jbyte* card_ptr) {
488 // Currently, we should only have to clean the card if filter_young
489 // is true and vice versa.
490 if (filter_young) {
491 assert(card_ptr != NULL, "pre-condition");
492 } else {
493 assert(card_ptr == NULL, "pre-condition");
494 }
495 G1CollectedHeap* g1h = G1CollectedHeap::heap();
496
497 // If we're within a stop-world GC, then we might look at a card in a
498 // GC alloc region that extends onto a GC LAB, which may not be
499 // parseable. Stop such at the "saved_mark" of the region.
500 if (g1h->is_gc_active()) {
501 mr = mr.intersection(used_region_at_save_marks());
502 } else {
503 mr = mr.intersection(used_region());
504 }
505 if (mr.is_empty()) return NULL;
506 // Otherwise, find the obj that extends onto mr.start().
507
508 // The intersection of the incoming mr (for the card) and the
509 // allocated part of the region is non-empty. This implies that
510 // we have actually allocated into this region. The code in
511 // G1CollectedHeap.cpp that allocates a new region sets the
512 // is_young tag on the region before allocating. Thus we
513 // safely know if this region is young.
514 if (is_young() && filter_young) {
515 return NULL;
516 }
517
518 assert(!is_young(), "check value of filter_young");
519
520 // We can only clean the card here, after we make the decision that
521 // the card is not young. And we only clean the card if we have been
522 // asked to (i.e., card_ptr != NULL).
523 if (card_ptr != NULL) {
524 *card_ptr = CardTableModRefBS::clean_card_val();
525 // We must complete this write before we do any of the reads below.
526 OrderAccess::storeload();
527 }
528
529 // Cache the boundaries of the memory region in some const locals
530 HeapWord* const start = mr.start();
531 HeapWord* const end = mr.end();
532
533 // We used to use "block_start_careful" here. But we're actually happy
534 // to update the BOT while we do this...
535 HeapWord* cur = block_start(start);
536 assert(cur <= start, "Postcondition");
537
538 oop obj;
539
540 HeapWord* next = cur;
541 while (next <= start) {
542 cur = next;
543 obj = oop(cur);
544 if (obj->klass_or_null() == NULL) {
545 // Ran into an unparseable point.
546 return cur;
547 }
548 // Otherwise...
549 next = (cur + obj->size());
550 }
551
552 // If we finish the above loop...We have a parseable object that
553 // begins on or before the start of the memory region, and ends
554 // inside or spans the entire region.
555
556 assert(obj == oop(cur), "sanity");
557 assert(cur <= start &&
558 obj->klass_or_null() != NULL &&
559 (cur + obj->size()) > start,
560 "Loop postcondition");
561
562 if (!g1h->is_obj_dead(obj)) {
563 obj->oop_iterate(cl, mr);
564 }
565
566 while (cur < end) {
567 obj = oop(cur);
568 if (obj->klass_or_null() == NULL) {
569 // Ran into an unparseable point.
570 return cur;
571 };
572
573 // Otherwise:
574 next = (cur + obj->size());
575
576 if (!g1h->is_obj_dead(obj)) {
577 if (next < end || !obj->is_objArray()) {
578 // This object either does not span the MemRegion
579 // boundary, or if it does it's not an array.
580 // Apply closure to whole object.
581 obj->oop_iterate(cl);
582 } else {
583 // This obj is an array that spans the boundary.
584 // Stop at the boundary.
585 obj->oop_iterate(cl, mr);
586 }
587 }
588 cur = next;
589 }
590 return NULL;
591 }
592
593 void HeapRegion::print() const { print_on(gclog_or_tty); }
594 void HeapRegion::print_on(outputStream* st) const {
595 if (isHumongous()) {
596 if (startsHumongous())
597 st->print(" HS");
598 else
599 st->print(" HC");
600 } else {
601 st->print(" ");
602 }
603 if (in_collection_set())
604 st->print(" CS");
605 else
606 st->print(" ");
607 if (is_young())
608 st->print(is_survivor() ? " SU" : " Y ");
609 else
610 st->print(" ");
611 if (is_empty())
612 st->print(" F");
613 else
614 st->print(" ");
615 st->print(" TS %5d", _gc_time_stamp);
616 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
617 prev_top_at_mark_start(), next_top_at_mark_start());
618 G1OffsetTableContigSpace::print_on(st);
619 }
620
621 class VerifyLiveClosure: public OopClosure {
622 private:
623 G1CollectedHeap* _g1h;
624 CardTableModRefBS* _bs;
625 oop _containing_obj;
626 bool _failures;
627 int _n_failures;
628 VerifyOption _vo;
629 public:
630 // _vo == UsePrevMarking -> use "prev" marking information,
631 // _vo == UseNextMarking -> use "next" marking information,
632 // _vo == UseMarkWord -> use mark word from object header.
633 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
634 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
635 _failures(false), _n_failures(0), _vo(vo)
636 {
637 BarrierSet* bs = _g1h->barrier_set();
638 if (bs->is_a(BarrierSet::CardTableModRef))
639 _bs = (CardTableModRefBS*)bs;
640 }
641
642 void set_containing_obj(oop obj) {
643 _containing_obj = obj;
644 }
645
646 bool failures() { return _failures; }
647 int n_failures() { return _n_failures; }
648
649 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
650 virtual void do_oop( oop* p) { do_oop_work(p); }
651
652 void print_object(outputStream* out, oop obj) {
653 #ifdef PRODUCT
654 Klass* k = obj->klass();
655 const char* class_name = InstanceKlass::cast(k)->external_name();
656 out->print_cr("class name %s", class_name);
657 #else // PRODUCT
658 obj->print_on(out);
659 #endif // PRODUCT
660 }
661
662 template <class T>
663 void do_oop_work(T* p) {
664 assert(_containing_obj != NULL, "Precondition");
665 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
666 "Precondition");
667 T heap_oop = oopDesc::load_heap_oop(p);
668 if (!oopDesc::is_null(heap_oop)) {
669 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
670 bool failed = false;
671 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
672 MutexLockerEx x(ParGCRareEvent_lock,
673 Mutex::_no_safepoint_check_flag);
674
675 if (!_failures) {
676 gclog_or_tty->print_cr("");
677 gclog_or_tty->print_cr("----------");
678 }
679 if (!_g1h->is_in_closed_subset(obj)) {
680 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
681 gclog_or_tty->print_cr("Field "PTR_FORMAT
682 " of live obj "PTR_FORMAT" in region "
683 "["PTR_FORMAT", "PTR_FORMAT")",
684 p, (void*) _containing_obj,
685 from->bottom(), from->end());
686 print_object(gclog_or_tty, _containing_obj);
687 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
688 (void*) obj);
689 } else {
690 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
691 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
692 gclog_or_tty->print_cr("Field "PTR_FORMAT
693 " of live obj "PTR_FORMAT" in region "
694 "["PTR_FORMAT", "PTR_FORMAT")",
695 p, (void*) _containing_obj,
696 from->bottom(), from->end());
697 print_object(gclog_or_tty, _containing_obj);
698 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
699 "["PTR_FORMAT", "PTR_FORMAT")",
700 (void*) obj, to->bottom(), to->end());
701 print_object(gclog_or_tty, obj);
702 }
703 gclog_or_tty->print_cr("----------");
704 gclog_or_tty->flush();
705 _failures = true;
706 failed = true;
707 _n_failures++;
708 }
709
710 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
711 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
712 HeapRegion* to = _g1h->heap_region_containing(obj);
713 if (from != NULL && to != NULL &&
714 from != to &&
715 !to->isHumongous()) {
716 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
717 jbyte cv_field = *_bs->byte_for_const(p);
718 const jbyte dirty = CardTableModRefBS::dirty_card_val();
719
720 bool is_bad = !(from->is_young()
721 || to->rem_set()->contains_reference(p)
722 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
723 (_containing_obj->is_objArray() ?
724 cv_field == dirty
725 : cv_obj == dirty || cv_field == dirty));
726 if (is_bad) {
727 MutexLockerEx x(ParGCRareEvent_lock,
728 Mutex::_no_safepoint_check_flag);
729
730 if (!_failures) {
731 gclog_or_tty->print_cr("");
732 gclog_or_tty->print_cr("----------");
733 }
734 gclog_or_tty->print_cr("Missing rem set entry:");
735 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
736 "of obj "PTR_FORMAT", "
737 "in region "HR_FORMAT,
738 p, (void*) _containing_obj,
739 HR_FORMAT_PARAMS(from));
740 _containing_obj->print_on(gclog_or_tty);
741 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
742 "in region "HR_FORMAT,
743 (void*) obj,
744 HR_FORMAT_PARAMS(to));
745 obj->print_on(gclog_or_tty);
746 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
747 cv_obj, cv_field);
748 gclog_or_tty->print_cr("----------");
749 gclog_or_tty->flush();
750 _failures = true;
751 if (!failed) _n_failures++;
752 }
753 }
754 }
755 }
756 }
757 };
758
759 // This really ought to be commoned up into OffsetTableContigSpace somehow.
760 // We would need a mechanism to make that code skip dead objects.
761
762 void HeapRegion::verify(VerifyOption vo,
763 bool* failures) const {
764 G1CollectedHeap* g1 = G1CollectedHeap::heap();
765 *failures = false;
766 HeapWord* p = bottom();
767 HeapWord* prev_p = NULL;
768 VerifyLiveClosure vl_cl(g1, vo);
769 bool is_humongous = isHumongous();
770 bool do_bot_verify = !is_young();
771 size_t object_num = 0;
772 while (p < top()) {
773 oop obj = oop(p);
774 size_t obj_size = obj->size();
775 object_num += 1;
776
777 if (is_humongous != g1->isHumongous(obj_size)) {
778 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
779 SIZE_FORMAT" words) in a %shumongous region",
780 p, g1->isHumongous(obj_size) ? "" : "non-",
781 obj_size, is_humongous ? "" : "non-");
782 *failures = true;
783 return;
784 }
785
786 // If it returns false, verify_for_object() will output the
787 // appropriate messasge.
788 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
789 *failures = true;
790 return;
791 }
792
793 if (!g1->is_obj_dead_cond(obj, this, vo)) {
794 if (obj->is_oop()) {
795 Klass* klass = obj->klass();
796 if (!klass->is_metadata()) {
797 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
798 "not metadata", klass, obj);
799 *failures = true;
800 return;
801 } else if (!klass->is_klass()) {
802 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
803 "not a klass", klass, obj);
804 *failures = true;
805 return;
806 } else {
807 vl_cl.set_containing_obj(obj);
808 obj->oop_iterate_no_header(&vl_cl);
809 if (vl_cl.failures()) {
810 *failures = true;
811 }
812 if (G1MaxVerifyFailures >= 0 &&
813 vl_cl.n_failures() >= G1MaxVerifyFailures) {
814 return;
815 }
816 }
817 } else {
818 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
819 *failures = true;
820 return;
821 }
822 }
823 prev_p = p;
824 p += obj_size;
825 }
826
827 if (p != top()) {
828 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
829 "does not match top "PTR_FORMAT, p, top());
830 *failures = true;
831 return;
832 }
833
834 HeapWord* the_end = end();
835 assert(p == top(), "it should still hold");
836 // Do some extra BOT consistency checking for addresses in the
837 // range [top, end). BOT look-ups in this range should yield
838 // top. No point in doing that if top == end (there's nothing there).
839 if (p < the_end) {
840 // Look up top
841 HeapWord* addr_1 = p;
842 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
843 if (b_start_1 != p) {
844 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
845 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
846 addr_1, b_start_1, p);
847 *failures = true;
848 return;
849 }
850
851 // Look up top + 1
852 HeapWord* addr_2 = p + 1;
853 if (addr_2 < the_end) {
854 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
855 if (b_start_2 != p) {
856 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
857 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
858 addr_2, b_start_2, p);
859 *failures = true;
860 return;
861 }
862 }
863
864 // Look up an address between top and end
865 size_t diff = pointer_delta(the_end, p) / 2;
866 HeapWord* addr_3 = p + diff;
867 if (addr_3 < the_end) {
868 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
869 if (b_start_3 != p) {
870 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
871 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
872 addr_3, b_start_3, p);
873 *failures = true;
874 return;
875 }
876 }
877
878 // Loook up end - 1
879 HeapWord* addr_4 = the_end - 1;
880 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
881 if (b_start_4 != p) {
882 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
883 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
884 addr_4, b_start_4, p);
885 *failures = true;
886 return;
887 }
888 }
889
890 if (is_humongous && object_num > 1) {
891 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
892 "but has "SIZE_FORMAT", objects",
893 bottom(), end(), object_num);
894 *failures = true;
895 return;
896 }
897 }
898
899 void HeapRegion::verify() const {
900 bool dummy = false;
901 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
902 }
903
904 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
905 // away eventually.
906
907 void G1OffsetTableContigSpace::clear(bool mangle_space) {
908 ContiguousSpace::clear(mangle_space);
909 _offsets.zero_bottom_entry();
910 _offsets.initialize_threshold();
911 }
912
913 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
914 Space::set_bottom(new_bottom);
915 _offsets.set_bottom(new_bottom);
916 }
917
918 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
919 Space::set_end(new_end);
920 _offsets.resize(new_end - bottom());
921 }
922
923 void G1OffsetTableContigSpace::print() const {
924 print_short();
925 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
926 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
927 bottom(), top(), _offsets.threshold(), end());
928 }
929
930 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
931 return _offsets.initialize_threshold();
932 }
933
934 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
935 HeapWord* end) {
936 _offsets.alloc_block(start, end);
937 return _offsets.threshold();
938 }
939
940 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
941 G1CollectedHeap* g1h = G1CollectedHeap::heap();
942 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
943 if (_gc_time_stamp < g1h->get_gc_time_stamp())
944 return top();
945 else
946 return ContiguousSpace::saved_mark_word();
947 }
948
949 void G1OffsetTableContigSpace::set_saved_mark() {
950 G1CollectedHeap* g1h = G1CollectedHeap::heap();
951 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
952
953 if (_gc_time_stamp < curr_gc_time_stamp) {
954 // The order of these is important, as another thread might be
955 // about to start scanning this region. If it does so after
956 // set_saved_mark and before _gc_time_stamp = ..., then the latter
957 // will be false, and it will pick up top() as the high water mark
958 // of region. If it does so after _gc_time_stamp = ..., then it
959 // will pick up the right saved_mark_word() as the high water mark
960 // of the region. Either way, the behaviour will be correct.
961 ContiguousSpace::set_saved_mark();
962 OrderAccess::storestore();
963 _gc_time_stamp = curr_gc_time_stamp;
964 // No need to do another barrier to flush the writes above. If
965 // this is called in parallel with other threads trying to
966 // allocate into the region, the caller should call this while
967 // holding a lock and when the lock is released the writes will be
968 // flushed.
969 }
970 }
971
972 G1OffsetTableContigSpace::
973 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
974 MemRegion mr) :
975 _offsets(sharedOffsetArray, mr),
976 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
977 _gc_time_stamp(0)
978 {
979 _offsets.set_space(this);
980 // false ==> we'll do the clearing if there's clearing to be done.
981 ContiguousSpace::initialize(mr, false, SpaceDecorator::Mangle);
982 _offsets.zero_bottom_entry();
983 _offsets.initialize_threshold();
984 }