comparison src/share/vm/gc_implementation/g1/heapRegion.cpp @ 12355:cefad50507d8

Merge with hs25-b53
author Gilles Duboscq <duboscq@ssw.jku.at>
date Fri, 11 Oct 2013 10:38:03 +0200
parents 3cce976666d9 190899198332
children 096c224171c4
comparison
equal deleted inserted replaced
12058:ccb4f2af2319 12355:cefad50507d8
1 /* 1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. 2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 * 4 *
5 * This code is free software; you can redistribute it and/or modify it 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 6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. 7 * published by the Free Software Foundation.
21 * questions. 21 * questions.
22 * 22 *
23 */ 23 */
24 24
25 #include "precompiled.hpp" 25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
26 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" 27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1OopClosures.inline.hpp" 29 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
29 #include "gc_implementation/g1/heapRegion.inline.hpp" 30 #include "gc_implementation/g1/heapRegion.inline.hpp"
30 #include "gc_implementation/g1/heapRegionRemSet.hpp" 31 #include "gc_implementation/g1/heapRegionRemSet.hpp"
47 _hr(hr), _fk(fk), _g1(g1) { } 48 _hr(hr), _fk(fk), _g1(g1) { }
48 49
49 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 50 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
50 OopClosure* oc) : 51 OopClosure* oc) :
51 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { } 52 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
53
54 template<class ClosureType>
55 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
56 HeapRegion* hr,
57 HeapWord* cur, HeapWord* top) {
58 oop cur_oop = oop(cur);
59 int oop_size = cur_oop->size();
60 HeapWord* next_obj = cur + oop_size;
61 while (next_obj < top) {
62 // Keep filtering the remembered set.
63 if (!g1h->is_obj_dead(cur_oop, hr)) {
64 // Bottom lies entirely below top, so we can call the
65 // non-memRegion version of oop_iterate below.
66 cur_oop->oop_iterate(cl);
67 }
68 cur = next_obj;
69 cur_oop = oop(cur);
70 oop_size = cur_oop->size();
71 next_obj = cur + oop_size;
72 }
73 return cur;
74 }
75
76 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
77 HeapWord* bottom,
78 HeapWord* top,
79 ExtendedOopClosure* cl) {
80 G1CollectedHeap* g1h = _g1;
81 int oop_size;
82 ExtendedOopClosure* cl2 = NULL;
83
84 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
85 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
86
87 switch (_fk) {
88 case NoFilterKind: cl2 = cl; break;
89 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
90 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
91 default: ShouldNotReachHere();
92 }
93
94 // Start filtering what we add to the remembered set. If the object is
95 // not considered dead, either because it is marked (in the mark bitmap)
96 // or it was allocated after marking finished, then we add it. Otherwise
97 // we can safely ignore the object.
98 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
99 oop_size = oop(bottom)->oop_iterate(cl2, mr);
100 } else {
101 oop_size = oop(bottom)->size();
102 }
103
104 bottom += oop_size;
105
106 if (bottom < top) {
107 // We replicate the loop below for several kinds of possible filters.
108 switch (_fk) {
109 case NoFilterKind:
110 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
111 break;
112
113 case IntoCSFilterKind: {
114 FilterIntoCSClosure filt(this, g1h, cl);
115 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
116 break;
117 }
118
119 case OutOfRegionFilterKind: {
120 FilterOutOfRegionClosure filt(_hr, cl);
121 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
122 break;
123 }
124
125 default:
126 ShouldNotReachHere();
127 }
128
129 // Last object. Need to do dead-obj filtering here too.
130 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
131 oop(bottom)->oop_iterate(cl2, mr);
132 }
133 }
134 }
135
136 // Minimum region size; we won't go lower than that.
137 // We might want to decrease this in the future, to deal with small
138 // heaps a bit more efficiently.
139 #define MIN_REGION_SIZE ( 1024 * 1024 )
140
141 // Maximum region size; we don't go higher than that. There's a good
142 // reason for having an upper bound. We don't want regions to get too
143 // large, otherwise cleanup's effectiveness would decrease as there
144 // will be fewer opportunities to find totally empty regions after
145 // marking.
146 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
147
148 // The automatic region size calculation will try to have around this
149 // many regions in the heap (based on the min heap size).
150 #define TARGET_REGION_NUMBER 2048
151
152 size_t HeapRegion::max_region_size() {
153 return (size_t)MAX_REGION_SIZE;
154 }
155
156 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
157 uintx region_size = G1HeapRegionSize;
158 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
159 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
160 region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
161 (uintx) MIN_REGION_SIZE);
162 }
163
164 int region_size_log = log2_long((jlong) region_size);
165 // Recalculate the region size to make sure it's a power of
166 // 2. This means that region_size is the largest power of 2 that's
167 // <= what we've calculated so far.
168 region_size = ((uintx)1 << region_size_log);
169
170 // Now make sure that we don't go over or under our limits.
171 if (region_size < MIN_REGION_SIZE) {
172 region_size = MIN_REGION_SIZE;
173 } else if (region_size > MAX_REGION_SIZE) {
174 region_size = MAX_REGION_SIZE;
175 }
176
177 if (region_size != G1HeapRegionSize) {
178 // Update the flag to make sure that PrintFlagsFinal logs the correct value
179 FLAG_SET_ERGO(uintx, G1HeapRegionSize, region_size);
180 }
181
182 // And recalculate the log.
183 region_size_log = log2_long((jlong) region_size);
184
185 // Now, set up the globals.
186 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
187 LogOfHRGrainBytes = region_size_log;
188
189 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
190 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
191
192 guarantee(GrainBytes == 0, "we should only set it once");
193 // The cast to int is safe, given that we've bounded region_size by
194 // MIN_REGION_SIZE and MAX_REGION_SIZE.
195 GrainBytes = (size_t)region_size;
196
197 guarantee(GrainWords == 0, "we should only set it once");
198 GrainWords = GrainBytes >> LogHeapWordSize;
199 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
200
201 guarantee(CardsPerRegion == 0, "we should only set it once");
202 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
203 }
204
205 void HeapRegion::reset_after_compaction() {
206 G1OffsetTableContigSpace::reset_after_compaction();
207 // After a compaction the mark bitmap is invalid, so we must
208 // treat all objects as being inside the unmarked area.
209 zero_marked_bytes();
210 init_top_at_mark_start();
211 }
212
213 void HeapRegion::hr_clear(bool par, bool clear_space) {
214 assert(_humongous_type == NotHumongous,
215 "we should have already filtered out humongous regions");
216 assert(_humongous_start_region == NULL,
217 "we should have already filtered out humongous regions");
218 assert(_end == _orig_end,
219 "we should have already filtered out humongous regions");
220
221 _in_collection_set = false;
222
223 set_young_index_in_cset(-1);
224 uninstall_surv_rate_group();
225 set_young_type(NotYoung);
226 reset_pre_dummy_top();
227
228 if (!par) {
229 // If this is parallel, this will be done later.
230 HeapRegionRemSet* hrrs = rem_set();
231 hrrs->clear();
232 _claimed = InitialClaimValue;
233 }
234 zero_marked_bytes();
235
236 _offsets.resize(HeapRegion::GrainWords);
237 init_top_at_mark_start();
238 if (clear_space) clear(SpaceDecorator::Mangle);
239 }
240
241 void HeapRegion::par_clear() {
242 assert(used() == 0, "the region should have been already cleared");
243 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
244 HeapRegionRemSet* hrrs = rem_set();
245 hrrs->clear();
246 CardTableModRefBS* ct_bs =
247 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
248 ct_bs->clear(MemRegion(bottom(), end()));
249 }
250
251 void HeapRegion::calc_gc_efficiency() {
252 // GC efficiency is the ratio of how much space would be
253 // reclaimed over how long we predict it would take to reclaim it.
254 G1CollectedHeap* g1h = G1CollectedHeap::heap();
255 G1CollectorPolicy* g1p = g1h->g1_policy();
256
257 // Retrieve a prediction of the elapsed time for this region for
258 // a mixed gc because the region will only be evacuated during a
259 // mixed gc.
260 double region_elapsed_time_ms =
261 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
262 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
263 }
264
265 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
266 assert(!isHumongous(), "sanity / pre-condition");
267 assert(end() == _orig_end,
268 "Should be normal before the humongous object allocation");
269 assert(top() == bottom(), "should be empty");
270 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
271
272 _humongous_type = StartsHumongous;
273 _humongous_start_region = this;
274
275 set_end(new_end);
276 _offsets.set_for_starts_humongous(new_top);
277 }
278
279 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
280 assert(!isHumongous(), "sanity / pre-condition");
281 assert(end() == _orig_end,
282 "Should be normal before the humongous object allocation");
283 assert(top() == bottom(), "should be empty");
284 assert(first_hr->startsHumongous(), "pre-condition");
285
286 _humongous_type = ContinuesHumongous;
287 _humongous_start_region = first_hr;
288 }
289
290 void HeapRegion::set_notHumongous() {
291 assert(isHumongous(), "pre-condition");
292
293 if (startsHumongous()) {
294 assert(top() <= end(), "pre-condition");
295 set_end(_orig_end);
296 if (top() > end()) {
297 // at least one "continues humongous" region after it
298 set_top(end());
299 }
300 } else {
301 // continues humongous
302 assert(end() == _orig_end, "sanity");
303 }
304
305 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
306 _humongous_type = NotHumongous;
307 _humongous_start_region = NULL;
308 }
309
310 bool HeapRegion::claimHeapRegion(jint claimValue) {
311 jint current = _claimed;
312 if (current != claimValue) {
313 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
314 if (res == current) {
315 return true;
316 }
317 }
318 return false;
319 }
320
321 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
322 HeapWord* low = addr;
323 HeapWord* high = end();
324 while (low < high) {
325 size_t diff = pointer_delta(high, low);
326 // Must add one below to bias toward the high amount. Otherwise, if
327 // "high" were at the desired value, and "low" were one less, we
328 // would not converge on "high". This is not symmetric, because
329 // we set "high" to a block start, which might be the right one,
330 // which we don't do for "low".
331 HeapWord* middle = low + (diff+1)/2;
332 if (middle == high) return high;
333 HeapWord* mid_bs = block_start_careful(middle);
334 if (mid_bs < addr) {
335 low = middle;
336 } else {
337 high = mid_bs;
338 }
339 }
340 assert(low == high && low >= addr, "Didn't work.");
341 return low;
342 }
343
344 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
345 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
346 #endif // _MSC_VER
347
348
349 HeapRegion::HeapRegion(uint hrs_index,
350 G1BlockOffsetSharedArray* sharedOffsetArray,
351 MemRegion mr) :
352 G1OffsetTableContigSpace(sharedOffsetArray, mr),
353 _hrs_index(hrs_index),
354 _humongous_type(NotHumongous), _humongous_start_region(NULL),
355 _in_collection_set(false),
356 _next_in_special_set(NULL), _orig_end(NULL),
357 _claimed(InitialClaimValue), _evacuation_failed(false),
358 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
359 _young_type(NotYoung), _next_young_region(NULL),
360 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
361 #ifdef ASSERT
362 _containing_set(NULL),
363 #endif // ASSERT
364 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
365 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
366 _predicted_bytes_to_copy(0)
367 {
368 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
369 _orig_end = mr.end();
370 // Note that initialize() will set the start of the unmarked area of the
371 // region.
372 hr_clear(false /*par*/, false /*clear_space*/);
373 set_top(bottom());
374 set_saved_mark();
375
376 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
377 }
378
379 CompactibleSpace* HeapRegion::next_compaction_space() const {
380 // We're not using an iterator given that it will wrap around when
381 // it reaches the last region and this is not what we want here.
382 G1CollectedHeap* g1h = G1CollectedHeap::heap();
383 uint index = hrs_index() + 1;
384 while (index < g1h->n_regions()) {
385 HeapRegion* hr = g1h->region_at(index);
386 if (!hr->isHumongous()) {
387 return hr;
388 }
389 index += 1;
390 }
391 return NULL;
392 }
393
394 void HeapRegion::save_marks() {
395 set_saved_mark();
396 }
397
398 void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
399 HeapWord* p = mr.start();
400 HeapWord* e = mr.end();
401 oop obj;
402 while (p < e) {
403 obj = oop(p);
404 p += obj->oop_iterate(cl);
405 }
406 assert(p == e, "bad memregion: doesn't end on obj boundary");
407 }
408
409 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
410 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
411 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
412 }
413 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
414
415
416 void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
417 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
418 }
419
420 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
421 bool during_conc_mark) {
422 // We always recreate the prev marking info and we'll explicitly
423 // mark all objects we find to be self-forwarded on the prev
424 // bitmap. So all objects need to be below PTAMS.
425 _prev_top_at_mark_start = top();
426 _prev_marked_bytes = 0;
427
428 if (during_initial_mark) {
429 // During initial-mark, we'll also explicitly mark all objects
430 // we find to be self-forwarded on the next bitmap. So all
431 // objects need to be below NTAMS.
432 _next_top_at_mark_start = top();
433 _next_marked_bytes = 0;
434 } else if (during_conc_mark) {
435 // During concurrent mark, all objects in the CSet (including
436 // the ones we find to be self-forwarded) are implicitly live.
437 // So all objects need to be above NTAMS.
438 _next_top_at_mark_start = bottom();
439 _next_marked_bytes = 0;
440 }
441 }
442
443 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
444 bool during_conc_mark,
445 size_t marked_bytes) {
446 assert(0 <= marked_bytes && marked_bytes <= used(),
447 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
448 marked_bytes, used()));
449 _prev_marked_bytes = marked_bytes;
450 }
451
452 HeapWord*
453 HeapRegion::object_iterate_mem_careful(MemRegion mr,
454 ObjectClosure* cl) {
455 G1CollectedHeap* g1h = G1CollectedHeap::heap();
456 // We used to use "block_start_careful" here. But we're actually happy
457 // to update the BOT while we do this...
458 HeapWord* cur = block_start(mr.start());
459 mr = mr.intersection(used_region());
460 if (mr.is_empty()) return NULL;
461 // Otherwise, find the obj that extends onto mr.start().
462
463 assert(cur <= mr.start()
464 && (oop(cur)->klass_or_null() == NULL ||
465 cur + oop(cur)->size() > mr.start()),
466 "postcondition of block_start");
467 oop obj;
468 while (cur < mr.end()) {
469 obj = oop(cur);
470 if (obj->klass_or_null() == NULL) {
471 // Ran into an unparseable point.
472 return cur;
473 } else if (!g1h->is_obj_dead(obj)) {
474 cl->do_object(obj);
475 }
476 if (cl->abort()) return cur;
477 // The check above must occur before the operation below, since an
478 // abort might invalidate the "size" operation.
479 cur += obj->size();
480 }
481 return NULL;
482 }
483
484 HeapWord*
485 HeapRegion::
486 oops_on_card_seq_iterate_careful(MemRegion mr,
487 FilterOutOfRegionClosure* cl,
488 bool filter_young,
489 jbyte* card_ptr) {
490 // Currently, we should only have to clean the card if filter_young
491 // is true and vice versa.
492 if (filter_young) {
493 assert(card_ptr != NULL, "pre-condition");
494 } else {
495 assert(card_ptr == NULL, "pre-condition");
496 }
497 G1CollectedHeap* g1h = G1CollectedHeap::heap();
498
499 // If we're within a stop-world GC, then we might look at a card in a
500 // GC alloc region that extends onto a GC LAB, which may not be
501 // parseable. Stop such at the "saved_mark" of the region.
502 if (g1h->is_gc_active()) {
503 mr = mr.intersection(used_region_at_save_marks());
504 } else {
505 mr = mr.intersection(used_region());
506 }
507 if (mr.is_empty()) return NULL;
508 // Otherwise, find the obj that extends onto mr.start().
509
510 // The intersection of the incoming mr (for the card) and the
511 // allocated part of the region is non-empty. This implies that
512 // we have actually allocated into this region. The code in
513 // G1CollectedHeap.cpp that allocates a new region sets the
514 // is_young tag on the region before allocating. Thus we
515 // safely know if this region is young.
516 if (is_young() && filter_young) {
517 return NULL;
518 }
519
520 assert(!is_young(), "check value of filter_young");
521
522 // We can only clean the card here, after we make the decision that
523 // the card is not young. And we only clean the card if we have been
524 // asked to (i.e., card_ptr != NULL).
525 if (card_ptr != NULL) {
526 *card_ptr = CardTableModRefBS::clean_card_val();
527 // We must complete this write before we do any of the reads below.
528 OrderAccess::storeload();
529 }
530
531 // Cache the boundaries of the memory region in some const locals
532 HeapWord* const start = mr.start();
533 HeapWord* const end = mr.end();
534
535 // We used to use "block_start_careful" here. But we're actually happy
536 // to update the BOT while we do this...
537 HeapWord* cur = block_start(start);
538 assert(cur <= start, "Postcondition");
539
540 oop obj;
541
542 HeapWord* next = cur;
543 while (next <= start) {
544 cur = next;
545 obj = oop(cur);
546 if (obj->klass_or_null() == NULL) {
547 // Ran into an unparseable point.
548 return cur;
549 }
550 // Otherwise...
551 next = (cur + obj->size());
552 }
553
554 // If we finish the above loop...We have a parseable object that
555 // begins on or before the start of the memory region, and ends
556 // inside or spans the entire region.
557
558 assert(obj == oop(cur), "sanity");
559 assert(cur <= start &&
560 obj->klass_or_null() != NULL &&
561 (cur + obj->size()) > start,
562 "Loop postcondition");
563
564 if (!g1h->is_obj_dead(obj)) {
565 obj->oop_iterate(cl, mr);
566 }
567
568 while (cur < end) {
569 obj = oop(cur);
570 if (obj->klass_or_null() == NULL) {
571 // Ran into an unparseable point.
572 return cur;
573 };
574
575 // Otherwise:
576 next = (cur + obj->size());
577
578 if (!g1h->is_obj_dead(obj)) {
579 if (next < end || !obj->is_objArray()) {
580 // This object either does not span the MemRegion
581 // boundary, or if it does it's not an array.
582 // Apply closure to whole object.
583 obj->oop_iterate(cl);
584 } else {
585 // This obj is an array that spans the boundary.
586 // Stop at the boundary.
587 obj->oop_iterate(cl, mr);
588 }
589 }
590 cur = next;
591 }
592 return NULL;
593 }
594
595 // Code roots support
596
597 void HeapRegion::add_strong_code_root(nmethod* nm) {
598 HeapRegionRemSet* hrrs = rem_set();
599 hrrs->add_strong_code_root(nm);
600 }
601
602 void HeapRegion::remove_strong_code_root(nmethod* nm) {
603 HeapRegionRemSet* hrrs = rem_set();
604 hrrs->remove_strong_code_root(nm);
605 }
606
607 void HeapRegion::migrate_strong_code_roots() {
608 assert(in_collection_set(), "only collection set regions");
609 assert(!isHumongous(), "not humongous regions");
610
611 HeapRegionRemSet* hrrs = rem_set();
612 hrrs->migrate_strong_code_roots();
613 }
614
615 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
616 HeapRegionRemSet* hrrs = rem_set();
617 hrrs->strong_code_roots_do(blk);
618 }
619
620 class VerifyStrongCodeRootOopClosure: public OopClosure {
621 const HeapRegion* _hr;
622 nmethod* _nm;
623 bool _failures;
624 bool _has_oops_in_region;
625
626 template <class T> void do_oop_work(T* p) {
627 T heap_oop = oopDesc::load_heap_oop(p);
628 if (!oopDesc::is_null(heap_oop)) {
629 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
630
631 // Note: not all the oops embedded in the nmethod are in the
632 // current region. We only look at those which are.
633 if (_hr->is_in(obj)) {
634 // Object is in the region. Check that its less than top
635 if (_hr->top() <= (HeapWord*)obj) {
636 // Object is above top
637 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
638 "["PTR_FORMAT", "PTR_FORMAT") is above "
639 "top "PTR_FORMAT,
640 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
641 _failures = true;
642 return;
643 }
644 // Nmethod has at least one oop in the current region
645 _has_oops_in_region = true;
646 }
647 }
648 }
649
650 public:
651 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
652 _hr(hr), _failures(false), _has_oops_in_region(false) {}
653
654 void do_oop(narrowOop* p) { do_oop_work(p); }
655 void do_oop(oop* p) { do_oop_work(p); }
656
657 bool failures() { return _failures; }
658 bool has_oops_in_region() { return _has_oops_in_region; }
659 };
660
661 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
662 const HeapRegion* _hr;
663 bool _failures;
664 public:
665 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
666 _hr(hr), _failures(false) {}
667
668 void do_code_blob(CodeBlob* cb) {
669 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
670 if (nm != NULL) {
671 // Verify that the nemthod is live
672 if (!nm->is_alive()) {
673 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
674 PTR_FORMAT" in its strong code roots",
675 _hr->bottom(), _hr->end(), nm);
676 _failures = true;
677 } else {
678 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
679 nm->oops_do(&oop_cl);
680 if (!oop_cl.has_oops_in_region()) {
681 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
682 PTR_FORMAT" in its strong code roots "
683 "with no pointers into region",
684 _hr->bottom(), _hr->end(), nm);
685 _failures = true;
686 } else if (oop_cl.failures()) {
687 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
688 "failures for nmethod "PTR_FORMAT,
689 _hr->bottom(), _hr->end(), nm);
690 _failures = true;
691 }
692 }
693 }
694 }
695
696 bool failures() { return _failures; }
697 };
698
699 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
700 if (!G1VerifyHeapRegionCodeRoots) {
701 // We're not verifying code roots.
702 return;
703 }
704 if (vo == VerifyOption_G1UseMarkWord) {
705 // Marking verification during a full GC is performed after class
706 // unloading, code cache unloading, etc so the strong code roots
707 // attached to each heap region are in an inconsistent state. They won't
708 // be consistent until the strong code roots are rebuilt after the
709 // actual GC. Skip verifying the strong code roots in this particular
710 // time.
711 assert(VerifyDuringGC, "only way to get here");
712 return;
713 }
714
715 HeapRegionRemSet* hrrs = rem_set();
716 int strong_code_roots_length = hrrs->strong_code_roots_list_length();
717
718 // if this region is empty then there should be no entries
719 // on its strong code root list
720 if (is_empty()) {
721 if (strong_code_roots_length > 0) {
722 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
723 "but has "INT32_FORMAT" code root entries",
724 bottom(), end(), strong_code_roots_length);
725 *failures = true;
726 }
727 return;
728 }
729
730 // An H-region should have an empty strong code root list
731 if (isHumongous()) {
732 if (strong_code_roots_length > 0) {
733 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
734 "but has "INT32_FORMAT" code root entries",
735 bottom(), end(), strong_code_roots_length);
736 *failures = true;
737 }
738 return;
739 }
740
741 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
742 strong_code_roots_do(&cb_cl);
743
744 if (cb_cl.failures()) {
745 *failures = true;
746 }
747 }
748
749 void HeapRegion::print() const { print_on(gclog_or_tty); }
750 void HeapRegion::print_on(outputStream* st) const {
751 if (isHumongous()) {
752 if (startsHumongous())
753 st->print(" HS");
754 else
755 st->print(" HC");
756 } else {
757 st->print(" ");
758 }
759 if (in_collection_set())
760 st->print(" CS");
761 else
762 st->print(" ");
763 if (is_young())
764 st->print(is_survivor() ? " SU" : " Y ");
765 else
766 st->print(" ");
767 if (is_empty())
768 st->print(" F");
769 else
770 st->print(" ");
771 st->print(" TS %5d", _gc_time_stamp);
772 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
773 prev_top_at_mark_start(), next_top_at_mark_start());
774 G1OffsetTableContigSpace::print_on(st);
775 }
52 776
53 class VerifyLiveClosure: public OopClosure { 777 class VerifyLiveClosure: public OopClosure {
54 private: 778 private:
55 G1CollectedHeap* _g1h; 779 G1CollectedHeap* _g1h;
56 CardTableModRefBS* _bs; 780 CardTableModRefBS* _bs;
186 } 910 }
187 } 911 }
188 } 912 }
189 }; 913 };
190 914
191 template<class ClosureType>
192 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
193 HeapRegion* hr,
194 HeapWord* cur, HeapWord* top) {
195 oop cur_oop = oop(cur);
196 int oop_size = cur_oop->size();
197 HeapWord* next_obj = cur + oop_size;
198 while (next_obj < top) {
199 // Keep filtering the remembered set.
200 if (!g1h->is_obj_dead(cur_oop, hr)) {
201 // Bottom lies entirely below top, so we can call the
202 // non-memRegion version of oop_iterate below.
203 cur_oop->oop_iterate(cl);
204 }
205 cur = next_obj;
206 cur_oop = oop(cur);
207 oop_size = cur_oop->size();
208 next_obj = cur + oop_size;
209 }
210 return cur;
211 }
212
213 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
214 HeapWord* bottom,
215 HeapWord* top,
216 ExtendedOopClosure* cl) {
217 G1CollectedHeap* g1h = _g1;
218 int oop_size;
219 ExtendedOopClosure* cl2 = NULL;
220
221 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
222 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
223
224 switch (_fk) {
225 case NoFilterKind: cl2 = cl; break;
226 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
227 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
228 default: ShouldNotReachHere();
229 }
230
231 // Start filtering what we add to the remembered set. If the object is
232 // not considered dead, either because it is marked (in the mark bitmap)
233 // or it was allocated after marking finished, then we add it. Otherwise
234 // we can safely ignore the object.
235 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
236 oop_size = oop(bottom)->oop_iterate(cl2, mr);
237 } else {
238 oop_size = oop(bottom)->size();
239 }
240
241 bottom += oop_size;
242
243 if (bottom < top) {
244 // We replicate the loop below for several kinds of possible filters.
245 switch (_fk) {
246 case NoFilterKind:
247 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
248 break;
249
250 case IntoCSFilterKind: {
251 FilterIntoCSClosure filt(this, g1h, cl);
252 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
253 break;
254 }
255
256 case OutOfRegionFilterKind: {
257 FilterOutOfRegionClosure filt(_hr, cl);
258 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
259 break;
260 }
261
262 default:
263 ShouldNotReachHere();
264 }
265
266 // Last object. Need to do dead-obj filtering here too.
267 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
268 oop(bottom)->oop_iterate(cl2, mr);
269 }
270 }
271 }
272
273 // Minimum region size; we won't go lower than that.
274 // We might want to decrease this in the future, to deal with small
275 // heaps a bit more efficiently.
276 #define MIN_REGION_SIZE ( 1024 * 1024 )
277
278 // Maximum region size; we don't go higher than that. There's a good
279 // reason for having an upper bound. We don't want regions to get too
280 // large, otherwise cleanup's effectiveness would decrease as there
281 // will be fewer opportunities to find totally empty regions after
282 // marking.
283 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
284
285 // The automatic region size calculation will try to have around this
286 // many regions in the heap (based on the min heap size).
287 #define TARGET_REGION_NUMBER 2048
288
289 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
290 // region_size in bytes
291 uintx region_size = G1HeapRegionSize;
292 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
293 // We base the automatic calculation on the min heap size. This
294 // can be problematic if the spread between min and max is quite
295 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
296 // the max size, the region size might be way too large for the
297 // min size. Either way, some users might have to set the region
298 // size manually for some -Xms / -Xmx combos.
299
300 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
301 (uintx) MIN_REGION_SIZE);
302 }
303
304 int region_size_log = log2_long((jlong) region_size);
305 // Recalculate the region size to make sure it's a power of
306 // 2. This means that region_size is the largest power of 2 that's
307 // <= what we've calculated so far.
308 region_size = ((uintx)1 << region_size_log);
309
310 // Now make sure that we don't go over or under our limits.
311 if (region_size < MIN_REGION_SIZE) {
312 region_size = MIN_REGION_SIZE;
313 } else if (region_size > MAX_REGION_SIZE) {
314 region_size = MAX_REGION_SIZE;
315 }
316
317 if (region_size != G1HeapRegionSize) {
318 // Update the flag to make sure that PrintFlagsFinal logs the correct value
319 FLAG_SET_ERGO(uintx, G1HeapRegionSize, region_size);
320 }
321
322 // And recalculate the log.
323 region_size_log = log2_long((jlong) region_size);
324
325 // Now, set up the globals.
326 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
327 LogOfHRGrainBytes = region_size_log;
328
329 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
330 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
331
332 guarantee(GrainBytes == 0, "we should only set it once");
333 // The cast to int is safe, given that we've bounded region_size by
334 // MIN_REGION_SIZE and MAX_REGION_SIZE.
335 GrainBytes = (size_t)region_size;
336
337 guarantee(GrainWords == 0, "we should only set it once");
338 GrainWords = GrainBytes >> LogHeapWordSize;
339 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
340
341 guarantee(CardsPerRegion == 0, "we should only set it once");
342 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
343 }
344
345 void HeapRegion::reset_after_compaction() {
346 G1OffsetTableContigSpace::reset_after_compaction();
347 // After a compaction the mark bitmap is invalid, so we must
348 // treat all objects as being inside the unmarked area.
349 zero_marked_bytes();
350 init_top_at_mark_start();
351 }
352
353 void HeapRegion::hr_clear(bool par, bool clear_space) {
354 assert(_humongous_type == NotHumongous,
355 "we should have already filtered out humongous regions");
356 assert(_humongous_start_region == NULL,
357 "we should have already filtered out humongous regions");
358 assert(_end == _orig_end,
359 "we should have already filtered out humongous regions");
360
361 _in_collection_set = false;
362
363 set_young_index_in_cset(-1);
364 uninstall_surv_rate_group();
365 set_young_type(NotYoung);
366 reset_pre_dummy_top();
367
368 if (!par) {
369 // If this is parallel, this will be done later.
370 HeapRegionRemSet* hrrs = rem_set();
371 if (hrrs != NULL) hrrs->clear();
372 _claimed = InitialClaimValue;
373 }
374 zero_marked_bytes();
375
376 _offsets.resize(HeapRegion::GrainWords);
377 init_top_at_mark_start();
378 if (clear_space) clear(SpaceDecorator::Mangle);
379 }
380
381 void HeapRegion::par_clear() {
382 assert(used() == 0, "the region should have been already cleared");
383 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
384 HeapRegionRemSet* hrrs = rem_set();
385 hrrs->clear();
386 CardTableModRefBS* ct_bs =
387 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
388 ct_bs->clear(MemRegion(bottom(), end()));
389 }
390
391 void HeapRegion::calc_gc_efficiency() {
392 // GC efficiency is the ratio of how much space would be
393 // reclaimed over how long we predict it would take to reclaim it.
394 G1CollectedHeap* g1h = G1CollectedHeap::heap();
395 G1CollectorPolicy* g1p = g1h->g1_policy();
396
397 // Retrieve a prediction of the elapsed time for this region for
398 // a mixed gc because the region will only be evacuated during a
399 // mixed gc.
400 double region_elapsed_time_ms =
401 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
402 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
403 }
404
405 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
406 assert(!isHumongous(), "sanity / pre-condition");
407 assert(end() == _orig_end,
408 "Should be normal before the humongous object allocation");
409 assert(top() == bottom(), "should be empty");
410 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
411
412 _humongous_type = StartsHumongous;
413 _humongous_start_region = this;
414
415 set_end(new_end);
416 _offsets.set_for_starts_humongous(new_top);
417 }
418
419 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
420 assert(!isHumongous(), "sanity / pre-condition");
421 assert(end() == _orig_end,
422 "Should be normal before the humongous object allocation");
423 assert(top() == bottom(), "should be empty");
424 assert(first_hr->startsHumongous(), "pre-condition");
425
426 _humongous_type = ContinuesHumongous;
427 _humongous_start_region = first_hr;
428 }
429
430 void HeapRegion::set_notHumongous() {
431 assert(isHumongous(), "pre-condition");
432
433 if (startsHumongous()) {
434 assert(top() <= end(), "pre-condition");
435 set_end(_orig_end);
436 if (top() > end()) {
437 // at least one "continues humongous" region after it
438 set_top(end());
439 }
440 } else {
441 // continues humongous
442 assert(end() == _orig_end, "sanity");
443 }
444
445 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
446 _humongous_type = NotHumongous;
447 _humongous_start_region = NULL;
448 }
449
450 bool HeapRegion::claimHeapRegion(jint claimValue) {
451 jint current = _claimed;
452 if (current != claimValue) {
453 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
454 if (res == current) {
455 return true;
456 }
457 }
458 return false;
459 }
460
461 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
462 HeapWord* low = addr;
463 HeapWord* high = end();
464 while (low < high) {
465 size_t diff = pointer_delta(high, low);
466 // Must add one below to bias toward the high amount. Otherwise, if
467 // "high" were at the desired value, and "low" were one less, we
468 // would not converge on "high". This is not symmetric, because
469 // we set "high" to a block start, which might be the right one,
470 // which we don't do for "low".
471 HeapWord* middle = low + (diff+1)/2;
472 if (middle == high) return high;
473 HeapWord* mid_bs = block_start_careful(middle);
474 if (mid_bs < addr) {
475 low = middle;
476 } else {
477 high = mid_bs;
478 }
479 }
480 assert(low == high && low >= addr, "Didn't work.");
481 return low;
482 }
483
484 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
485 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
486 #endif // _MSC_VER
487
488
489 HeapRegion::HeapRegion(uint hrs_index,
490 G1BlockOffsetSharedArray* sharedOffsetArray,
491 MemRegion mr) :
492 G1OffsetTableContigSpace(sharedOffsetArray, mr),
493 _hrs_index(hrs_index),
494 _humongous_type(NotHumongous), _humongous_start_region(NULL),
495 _in_collection_set(false),
496 _next_in_special_set(NULL), _orig_end(NULL),
497 _claimed(InitialClaimValue), _evacuation_failed(false),
498 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
499 _young_type(NotYoung), _next_young_region(NULL),
500 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
501 #ifdef ASSERT
502 _containing_set(NULL),
503 #endif // ASSERT
504 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
505 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
506 _predicted_bytes_to_copy(0)
507 {
508 _orig_end = mr.end();
509 // Note that initialize() will set the start of the unmarked area of the
510 // region.
511 hr_clear(false /*par*/, false /*clear_space*/);
512 set_top(bottom());
513 set_saved_mark();
514
515 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
516
517 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
518 }
519
520 CompactibleSpace* HeapRegion::next_compaction_space() const {
521 // We're not using an iterator given that it will wrap around when
522 // it reaches the last region and this is not what we want here.
523 G1CollectedHeap* g1h = G1CollectedHeap::heap();
524 uint index = hrs_index() + 1;
525 while (index < g1h->n_regions()) {
526 HeapRegion* hr = g1h->region_at(index);
527 if (!hr->isHumongous()) {
528 return hr;
529 }
530 index += 1;
531 }
532 return NULL;
533 }
534
535 void HeapRegion::save_marks() {
536 set_saved_mark();
537 }
538
539 void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
540 HeapWord* p = mr.start();
541 HeapWord* e = mr.end();
542 oop obj;
543 while (p < e) {
544 obj = oop(p);
545 p += obj->oop_iterate(cl);
546 }
547 assert(p == e, "bad memregion: doesn't end on obj boundary");
548 }
549
550 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
551 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
552 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
553 }
554 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
555
556
557 void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
558 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
559 }
560
561 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
562 bool during_conc_mark) {
563 // We always recreate the prev marking info and we'll explicitly
564 // mark all objects we find to be self-forwarded on the prev
565 // bitmap. So all objects need to be below PTAMS.
566 _prev_top_at_mark_start = top();
567 _prev_marked_bytes = 0;
568
569 if (during_initial_mark) {
570 // During initial-mark, we'll also explicitly mark all objects
571 // we find to be self-forwarded on the next bitmap. So all
572 // objects need to be below NTAMS.
573 _next_top_at_mark_start = top();
574 _next_marked_bytes = 0;
575 } else if (during_conc_mark) {
576 // During concurrent mark, all objects in the CSet (including
577 // the ones we find to be self-forwarded) are implicitly live.
578 // So all objects need to be above NTAMS.
579 _next_top_at_mark_start = bottom();
580 _next_marked_bytes = 0;
581 }
582 }
583
584 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
585 bool during_conc_mark,
586 size_t marked_bytes) {
587 assert(0 <= marked_bytes && marked_bytes <= used(),
588 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
589 marked_bytes, used()));
590 _prev_marked_bytes = marked_bytes;
591 }
592
593 HeapWord*
594 HeapRegion::object_iterate_mem_careful(MemRegion mr,
595 ObjectClosure* cl) {
596 G1CollectedHeap* g1h = G1CollectedHeap::heap();
597 // We used to use "block_start_careful" here. But we're actually happy
598 // to update the BOT while we do this...
599 HeapWord* cur = block_start(mr.start());
600 mr = mr.intersection(used_region());
601 if (mr.is_empty()) return NULL;
602 // Otherwise, find the obj that extends onto mr.start().
603
604 assert(cur <= mr.start()
605 && (oop(cur)->klass_or_null() == NULL ||
606 cur + oop(cur)->size() > mr.start()),
607 "postcondition of block_start");
608 oop obj;
609 while (cur < mr.end()) {
610 obj = oop(cur);
611 if (obj->klass_or_null() == NULL) {
612 // Ran into an unparseable point.
613 return cur;
614 } else if (!g1h->is_obj_dead(obj)) {
615 cl->do_object(obj);
616 }
617 if (cl->abort()) return cur;
618 // The check above must occur before the operation below, since an
619 // abort might invalidate the "size" operation.
620 cur += obj->size();
621 }
622 return NULL;
623 }
624
625 HeapWord*
626 HeapRegion::
627 oops_on_card_seq_iterate_careful(MemRegion mr,
628 FilterOutOfRegionClosure* cl,
629 bool filter_young,
630 jbyte* card_ptr) {
631 // Currently, we should only have to clean the card if filter_young
632 // is true and vice versa.
633 if (filter_young) {
634 assert(card_ptr != NULL, "pre-condition");
635 } else {
636 assert(card_ptr == NULL, "pre-condition");
637 }
638 G1CollectedHeap* g1h = G1CollectedHeap::heap();
639
640 // If we're within a stop-world GC, then we might look at a card in a
641 // GC alloc region that extends onto a GC LAB, which may not be
642 // parseable. Stop such at the "saved_mark" of the region.
643 if (g1h->is_gc_active()) {
644 mr = mr.intersection(used_region_at_save_marks());
645 } else {
646 mr = mr.intersection(used_region());
647 }
648 if (mr.is_empty()) return NULL;
649 // Otherwise, find the obj that extends onto mr.start().
650
651 // The intersection of the incoming mr (for the card) and the
652 // allocated part of the region is non-empty. This implies that
653 // we have actually allocated into this region. The code in
654 // G1CollectedHeap.cpp that allocates a new region sets the
655 // is_young tag on the region before allocating. Thus we
656 // safely know if this region is young.
657 if (is_young() && filter_young) {
658 return NULL;
659 }
660
661 assert(!is_young(), "check value of filter_young");
662
663 // We can only clean the card here, after we make the decision that
664 // the card is not young. And we only clean the card if we have been
665 // asked to (i.e., card_ptr != NULL).
666 if (card_ptr != NULL) {
667 *card_ptr = CardTableModRefBS::clean_card_val();
668 // We must complete this write before we do any of the reads below.
669 OrderAccess::storeload();
670 }
671
672 // Cache the boundaries of the memory region in some const locals
673 HeapWord* const start = mr.start();
674 HeapWord* const end = mr.end();
675
676 // We used to use "block_start_careful" here. But we're actually happy
677 // to update the BOT while we do this...
678 HeapWord* cur = block_start(start);
679 assert(cur <= start, "Postcondition");
680
681 oop obj;
682
683 HeapWord* next = cur;
684 while (next <= start) {
685 cur = next;
686 obj = oop(cur);
687 if (obj->klass_or_null() == NULL) {
688 // Ran into an unparseable point.
689 return cur;
690 }
691 // Otherwise...
692 next = (cur + obj->size());
693 }
694
695 // If we finish the above loop...We have a parseable object that
696 // begins on or before the start of the memory region, and ends
697 // inside or spans the entire region.
698
699 assert(obj == oop(cur), "sanity");
700 assert(cur <= start &&
701 obj->klass_or_null() != NULL &&
702 (cur + obj->size()) > start,
703 "Loop postcondition");
704
705 if (!g1h->is_obj_dead(obj)) {
706 obj->oop_iterate(cl, mr);
707 }
708
709 while (cur < end) {
710 obj = oop(cur);
711 if (obj->klass_or_null() == NULL) {
712 // Ran into an unparseable point.
713 return cur;
714 };
715
716 // Otherwise:
717 next = (cur + obj->size());
718
719 if (!g1h->is_obj_dead(obj)) {
720 if (next < end || !obj->is_objArray()) {
721 // This object either does not span the MemRegion
722 // boundary, or if it does it's not an array.
723 // Apply closure to whole object.
724 obj->oop_iterate(cl);
725 } else {
726 // This obj is an array that spans the boundary.
727 // Stop at the boundary.
728 obj->oop_iterate(cl, mr);
729 }
730 }
731 cur = next;
732 }
733 return NULL;
734 }
735
736 void HeapRegion::print() const { print_on(gclog_or_tty); }
737 void HeapRegion::print_on(outputStream* st) const {
738 if (isHumongous()) {
739 if (startsHumongous())
740 st->print(" HS");
741 else
742 st->print(" HC");
743 } else {
744 st->print(" ");
745 }
746 if (in_collection_set())
747 st->print(" CS");
748 else
749 st->print(" ");
750 if (is_young())
751 st->print(is_survivor() ? " SU" : " Y ");
752 else
753 st->print(" ");
754 if (is_empty())
755 st->print(" F");
756 else
757 st->print(" ");
758 st->print(" TS %5d", _gc_time_stamp);
759 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
760 prev_top_at_mark_start(), next_top_at_mark_start());
761 G1OffsetTableContigSpace::print_on(st);
762 }
763
764 void HeapRegion::verify() const {
765 bool dummy = false;
766 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
767 }
768
769 // This really ought to be commoned up into OffsetTableContigSpace somehow. 915 // This really ought to be commoned up into OffsetTableContigSpace somehow.
770 // We would need a mechanism to make that code skip dead objects. 916 // We would need a mechanism to make that code skip dead objects.
771 917
772 void HeapRegion::verify(VerifyOption vo, 918 void HeapRegion::verify(VerifyOption vo,
773 bool* failures) const { 919 bool* failures) const {
803 if (!g1->is_obj_dead_cond(obj, this, vo)) { 949 if (!g1->is_obj_dead_cond(obj, this, vo)) {
804 if (obj->is_oop()) { 950 if (obj->is_oop()) {
805 Klass* klass = obj->klass(); 951 Klass* klass = obj->klass();
806 if (!klass->is_metaspace_object()) { 952 if (!klass->is_metaspace_object()) {
807 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 953 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
808 "not metadata", klass, obj); 954 "not metadata", klass, (void *)obj);
809 *failures = true; 955 *failures = true;
810 return; 956 return;
811 } else if (!klass->is_klass()) { 957 } else if (!klass->is_klass()) {
812 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 958 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
813 "not a klass", klass, obj); 959 "not a klass", klass, (void *)obj);
814 *failures = true; 960 *failures = true;
815 return; 961 return;
816 } else { 962 } else {
817 vl_cl.set_containing_obj(obj); 963 vl_cl.set_containing_obj(obj);
818 obj->oop_iterate_no_header(&vl_cl); 964 obj->oop_iterate_no_header(&vl_cl);
823 vl_cl.n_failures() >= G1MaxVerifyFailures) { 969 vl_cl.n_failures() >= G1MaxVerifyFailures) {
824 return; 970 return;
825 } 971 }
826 } 972 }
827 } else { 973 } else {
828 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj); 974 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
829 *failures = true; 975 *failures = true;
830 return; 976 return;
831 } 977 }
832 } 978 }
833 prev_p = p; 979 prev_p = p;
902 "but has "SIZE_FORMAT", objects", 1048 "but has "SIZE_FORMAT", objects",
903 bottom(), end(), object_num); 1049 bottom(), end(), object_num);
904 *failures = true; 1050 *failures = true;
905 return; 1051 return;
906 } 1052 }
1053
1054 verify_strong_code_roots(vo, failures);
1055 }
1056
1057 void HeapRegion::verify() const {
1058 bool dummy = false;
1059 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
907 } 1060 }
908 1061
909 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 1062 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
910 // away eventually. 1063 // away eventually.
911 1064