Wed, 02 Nov 2011 08:04:23 +0100
7106751: G1: gc/gctests/nativeGC03 crashes VM with SIGSEGV
Summary: _cset_rs_update_cl[] was indexed with values beyond what it is set up to handle.
Reviewed-by: ysr, jmasa, johnc
1 /*
2 * Copyright (c) 2001, 2011, 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.
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23 */
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"
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;
42 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
43 HeapRegion* hr, OopClosure* cl,
44 CardTableModRefBS::PrecisionStyle precision,
45 FilterKind fk) :
46 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
47 _hr(hr), _fk(fk), _g1(g1)
48 { }
50 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
51 OopClosure* oc) :
52 _r_bottom(r->bottom()), _r_end(r->end()),
53 _oc(oc), _out_of_region(0)
54 {}
56 class VerifyLiveClosure: public OopClosure {
57 private:
58 G1CollectedHeap* _g1h;
59 CardTableModRefBS* _bs;
60 oop _containing_obj;
61 bool _failures;
62 int _n_failures;
63 VerifyOption _vo;
64 public:
65 // _vo == UsePrevMarking -> use "prev" marking information,
66 // _vo == UseNextMarking -> use "next" marking information,
67 // _vo == UseMarkWord -> use mark word from object header.
68 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
69 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
70 _failures(false), _n_failures(0), _vo(vo)
71 {
72 BarrierSet* bs = _g1h->barrier_set();
73 if (bs->is_a(BarrierSet::CardTableModRef))
74 _bs = (CardTableModRefBS*)bs;
75 }
77 void set_containing_obj(oop obj) {
78 _containing_obj = obj;
79 }
81 bool failures() { return _failures; }
82 int n_failures() { return _n_failures; }
84 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
85 virtual void do_oop( oop* p) { do_oop_work(p); }
87 void print_object(outputStream* out, oop obj) {
88 #ifdef PRODUCT
89 klassOop k = obj->klass();
90 const char* class_name = instanceKlass::cast(k)->external_name();
91 out->print_cr("class name %s", class_name);
92 #else // PRODUCT
93 obj->print_on(out);
94 #endif // PRODUCT
95 }
97 template <class T> void do_oop_work(T* p) {
98 assert(_containing_obj != NULL, "Precondition");
99 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
100 "Precondition");
101 T heap_oop = oopDesc::load_heap_oop(p);
102 if (!oopDesc::is_null(heap_oop)) {
103 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
104 bool failed = false;
105 if (!_g1h->is_in_closed_subset(obj) ||
106 _g1h->is_obj_dead_cond(obj, _vo)) {
107 if (!_failures) {
108 gclog_or_tty->print_cr("");
109 gclog_or_tty->print_cr("----------");
110 }
111 if (!_g1h->is_in_closed_subset(obj)) {
112 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
113 gclog_or_tty->print_cr("Field "PTR_FORMAT
114 " of live obj "PTR_FORMAT" in region "
115 "["PTR_FORMAT", "PTR_FORMAT")",
116 p, (void*) _containing_obj,
117 from->bottom(), from->end());
118 print_object(gclog_or_tty, _containing_obj);
119 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
120 (void*) obj);
121 } else {
122 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
123 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
124 gclog_or_tty->print_cr("Field "PTR_FORMAT
125 " of live obj "PTR_FORMAT" in region "
126 "["PTR_FORMAT", "PTR_FORMAT")",
127 p, (void*) _containing_obj,
128 from->bottom(), from->end());
129 print_object(gclog_or_tty, _containing_obj);
130 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
131 "["PTR_FORMAT", "PTR_FORMAT")",
132 (void*) obj, to->bottom(), to->end());
133 print_object(gclog_or_tty, obj);
134 }
135 gclog_or_tty->print_cr("----------");
136 _failures = true;
137 failed = true;
138 _n_failures++;
139 }
141 if (!_g1h->full_collection()) {
142 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
143 HeapRegion* to = _g1h->heap_region_containing(obj);
144 if (from != NULL && to != NULL &&
145 from != to &&
146 !to->isHumongous()) {
147 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
148 jbyte cv_field = *_bs->byte_for_const(p);
149 const jbyte dirty = CardTableModRefBS::dirty_card_val();
151 bool is_bad = !(from->is_young()
152 || to->rem_set()->contains_reference(p)
153 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
154 (_containing_obj->is_objArray() ?
155 cv_field == dirty
156 : cv_obj == dirty || cv_field == dirty));
157 if (is_bad) {
158 if (!_failures) {
159 gclog_or_tty->print_cr("");
160 gclog_or_tty->print_cr("----------");
161 }
162 gclog_or_tty->print_cr("Missing rem set entry:");
163 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
164 "of obj "PTR_FORMAT", "
165 "in region "HR_FORMAT,
166 p, (void*) _containing_obj,
167 HR_FORMAT_PARAMS(from));
168 _containing_obj->print_on(gclog_or_tty);
169 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
170 "in region "HR_FORMAT,
171 (void*) obj,
172 HR_FORMAT_PARAMS(to));
173 obj->print_on(gclog_or_tty);
174 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
175 cv_obj, cv_field);
176 gclog_or_tty->print_cr("----------");
177 _failures = true;
178 if (!failed) _n_failures++;
179 }
180 }
181 }
182 }
183 }
184 };
186 template<class ClosureType>
187 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
188 HeapRegion* hr,
189 HeapWord* cur, HeapWord* top) {
190 oop cur_oop = oop(cur);
191 int oop_size = cur_oop->size();
192 HeapWord* next_obj = cur + oop_size;
193 while (next_obj < top) {
194 // Keep filtering the remembered set.
195 if (!g1h->is_obj_dead(cur_oop, hr)) {
196 // Bottom lies entirely below top, so we can call the
197 // non-memRegion version of oop_iterate below.
198 cur_oop->oop_iterate(cl);
199 }
200 cur = next_obj;
201 cur_oop = oop(cur);
202 oop_size = cur_oop->size();
203 next_obj = cur + oop_size;
204 }
205 return cur;
206 }
208 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
209 HeapWord* bottom,
210 HeapWord* top,
211 OopClosure* cl) {
212 G1CollectedHeap* g1h = _g1;
213 int oop_size;
214 OopClosure* cl2 = NULL;
216 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
217 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
219 switch (_fk) {
220 case NoFilterKind: cl2 = cl; break;
221 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
222 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
223 default: ShouldNotReachHere();
224 }
226 // Start filtering what we add to the remembered set. If the object is
227 // not considered dead, either because it is marked (in the mark bitmap)
228 // or it was allocated after marking finished, then we add it. Otherwise
229 // we can safely ignore the object.
230 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
231 oop_size = oop(bottom)->oop_iterate(cl2, mr);
232 } else {
233 oop_size = oop(bottom)->size();
234 }
236 bottom += oop_size;
238 if (bottom < top) {
239 // We replicate the loop below for several kinds of possible filters.
240 switch (_fk) {
241 case NoFilterKind:
242 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
243 break;
245 case IntoCSFilterKind: {
246 FilterIntoCSClosure filt(this, g1h, cl);
247 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
248 break;
249 }
251 case OutOfRegionFilterKind: {
252 FilterOutOfRegionClosure filt(_hr, cl);
253 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
254 break;
255 }
257 default:
258 ShouldNotReachHere();
259 }
261 // Last object. Need to do dead-obj filtering here too.
262 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
263 oop(bottom)->oop_iterate(cl2, mr);
264 }
265 }
266 }
268 // Minimum region size; we won't go lower than that.
269 // We might want to decrease this in the future, to deal with small
270 // heaps a bit more efficiently.
271 #define MIN_REGION_SIZE ( 1024 * 1024 )
273 // Maximum region size; we don't go higher than that. There's a good
274 // reason for having an upper bound. We don't want regions to get too
275 // large, otherwise cleanup's effectiveness would decrease as there
276 // will be fewer opportunities to find totally empty regions after
277 // marking.
278 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
280 // The automatic region size calculation will try to have around this
281 // many regions in the heap (based on the min heap size).
282 #define TARGET_REGION_NUMBER 2048
284 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
285 // region_size in bytes
286 uintx region_size = G1HeapRegionSize;
287 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
288 // We base the automatic calculation on the min heap size. This
289 // can be problematic if the spread between min and max is quite
290 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
291 // the max size, the region size might be way too large for the
292 // min size. Either way, some users might have to set the region
293 // size manually for some -Xms / -Xmx combos.
295 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
296 (uintx) MIN_REGION_SIZE);
297 }
299 int region_size_log = log2_long((jlong) region_size);
300 // Recalculate the region size to make sure it's a power of
301 // 2. This means that region_size is the largest power of 2 that's
302 // <= what we've calculated so far.
303 region_size = ((uintx)1 << region_size_log);
305 // Now make sure that we don't go over or under our limits.
306 if (region_size < MIN_REGION_SIZE) {
307 region_size = MIN_REGION_SIZE;
308 } else if (region_size > MAX_REGION_SIZE) {
309 region_size = MAX_REGION_SIZE;
310 }
312 // And recalculate the log.
313 region_size_log = log2_long((jlong) region_size);
315 // Now, set up the globals.
316 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
317 LogOfHRGrainBytes = region_size_log;
319 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
320 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
322 guarantee(GrainBytes == 0, "we should only set it once");
323 // The cast to int is safe, given that we've bounded region_size by
324 // MIN_REGION_SIZE and MAX_REGION_SIZE.
325 GrainBytes = (size_t)region_size;
327 guarantee(GrainWords == 0, "we should only set it once");
328 GrainWords = GrainBytes >> LogHeapWordSize;
329 guarantee((size_t)(1 << LogOfHRGrainWords) == GrainWords, "sanity");
331 guarantee(CardsPerRegion == 0, "we should only set it once");
332 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
333 }
335 void HeapRegion::reset_after_compaction() {
336 G1OffsetTableContigSpace::reset_after_compaction();
337 // After a compaction the mark bitmap is invalid, so we must
338 // treat all objects as being inside the unmarked area.
339 zero_marked_bytes();
340 init_top_at_mark_start();
341 }
343 void HeapRegion::hr_clear(bool par, bool clear_space) {
344 assert(_humongous_type == NotHumongous,
345 "we should have already filtered out humongous regions");
346 assert(_humongous_start_region == NULL,
347 "we should have already filtered out humongous regions");
348 assert(_end == _orig_end,
349 "we should have already filtered out humongous regions");
351 _in_collection_set = false;
353 set_young_index_in_cset(-1);
354 uninstall_surv_rate_group();
355 set_young_type(NotYoung);
356 reset_pre_dummy_top();
358 if (!par) {
359 // If this is parallel, this will be done later.
360 HeapRegionRemSet* hrrs = rem_set();
361 if (hrrs != NULL) hrrs->clear();
362 _claimed = InitialClaimValue;
363 }
364 zero_marked_bytes();
365 set_sort_index(-1);
367 _offsets.resize(HeapRegion::GrainWords);
368 init_top_at_mark_start();
369 if (clear_space) clear(SpaceDecorator::Mangle);
370 }
372 void HeapRegion::par_clear() {
373 assert(used() == 0, "the region should have been already cleared");
374 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
375 HeapRegionRemSet* hrrs = rem_set();
376 hrrs->clear();
377 CardTableModRefBS* ct_bs =
378 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
379 ct_bs->clear(MemRegion(bottom(), end()));
380 }
382 // <PREDICTION>
383 void HeapRegion::calc_gc_efficiency() {
384 G1CollectedHeap* g1h = G1CollectedHeap::heap();
385 _gc_efficiency = (double) garbage_bytes() /
386 g1h->predict_region_elapsed_time_ms(this, false);
387 }
388 // </PREDICTION>
390 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
391 assert(!isHumongous(), "sanity / pre-condition");
392 assert(end() == _orig_end,
393 "Should be normal before the humongous object allocation");
394 assert(top() == bottom(), "should be empty");
395 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
397 _humongous_type = StartsHumongous;
398 _humongous_start_region = this;
400 set_end(new_end);
401 _offsets.set_for_starts_humongous(new_top);
402 }
404 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
405 assert(!isHumongous(), "sanity / pre-condition");
406 assert(end() == _orig_end,
407 "Should be normal before the humongous object allocation");
408 assert(top() == bottom(), "should be empty");
409 assert(first_hr->startsHumongous(), "pre-condition");
411 _humongous_type = ContinuesHumongous;
412 _humongous_start_region = first_hr;
413 }
415 void HeapRegion::set_notHumongous() {
416 assert(isHumongous(), "pre-condition");
418 if (startsHumongous()) {
419 assert(top() <= end(), "pre-condition");
420 set_end(_orig_end);
421 if (top() > end()) {
422 // at least one "continues humongous" region after it
423 set_top(end());
424 }
425 } else {
426 // continues humongous
427 assert(end() == _orig_end, "sanity");
428 }
430 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
431 _humongous_type = NotHumongous;
432 _humongous_start_region = NULL;
433 }
435 bool HeapRegion::claimHeapRegion(jint claimValue) {
436 jint current = _claimed;
437 if (current != claimValue) {
438 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
439 if (res == current) {
440 return true;
441 }
442 }
443 return false;
444 }
446 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
447 HeapWord* low = addr;
448 HeapWord* high = end();
449 while (low < high) {
450 size_t diff = pointer_delta(high, low);
451 // Must add one below to bias toward the high amount. Otherwise, if
452 // "high" were at the desired value, and "low" were one less, we
453 // would not converge on "high". This is not symmetric, because
454 // we set "high" to a block start, which might be the right one,
455 // which we don't do for "low".
456 HeapWord* middle = low + (diff+1)/2;
457 if (middle == high) return high;
458 HeapWord* mid_bs = block_start_careful(middle);
459 if (mid_bs < addr) {
460 low = middle;
461 } else {
462 high = mid_bs;
463 }
464 }
465 assert(low == high && low >= addr, "Didn't work.");
466 return low;
467 }
469 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
470 G1OffsetTableContigSpace::initialize(mr, false, mangle_space);
471 hr_clear(false/*par*/, clear_space);
472 }
473 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
474 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
475 #endif // _MSC_VER
478 HeapRegion::
479 HeapRegion(size_t hrs_index, G1BlockOffsetSharedArray* sharedOffsetArray,
480 MemRegion mr, bool is_zeroed)
481 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed),
482 _hrs_index(hrs_index),
483 _humongous_type(NotHumongous), _humongous_start_region(NULL),
484 _in_collection_set(false),
485 _next_in_special_set(NULL), _orig_end(NULL),
486 _claimed(InitialClaimValue), _evacuation_failed(false),
487 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1),
488 _gc_efficiency(0.0),
489 _young_type(NotYoung), _next_young_region(NULL),
490 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
491 #ifdef ASSERT
492 _containing_set(NULL),
493 #endif // ASSERT
494 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
495 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
496 _predicted_bytes_to_copy(0)
497 {
498 _orig_end = mr.end();
499 // Note that initialize() will set the start of the unmarked area of the
500 // region.
501 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
502 set_top(bottom());
503 set_saved_mark();
505 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
507 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
508 // In case the region is allocated during a pause, note the top.
509 // We haven't done any counting on a brand new region.
510 _top_at_conc_mark_count = bottom();
511 }
513 class NextCompactionHeapRegionClosure: public HeapRegionClosure {
514 const HeapRegion* _target;
515 bool _target_seen;
516 HeapRegion* _last;
517 CompactibleSpace* _res;
518 public:
519 NextCompactionHeapRegionClosure(const HeapRegion* target) :
520 _target(target), _target_seen(false), _res(NULL) {}
521 bool doHeapRegion(HeapRegion* cur) {
522 if (_target_seen) {
523 if (!cur->isHumongous()) {
524 _res = cur;
525 return true;
526 }
527 } else if (cur == _target) {
528 _target_seen = true;
529 }
530 return false;
531 }
532 CompactibleSpace* result() { return _res; }
533 };
535 CompactibleSpace* HeapRegion::next_compaction_space() const {
536 G1CollectedHeap* g1h = G1CollectedHeap::heap();
537 // cast away const-ness
538 HeapRegion* r = (HeapRegion*) this;
539 NextCompactionHeapRegionClosure blk(r);
540 g1h->heap_region_iterate_from(r, &blk);
541 return blk.result();
542 }
544 void HeapRegion::save_marks() {
545 set_saved_mark();
546 }
548 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) {
549 HeapWord* p = mr.start();
550 HeapWord* e = mr.end();
551 oop obj;
552 while (p < e) {
553 obj = oop(p);
554 p += obj->oop_iterate(cl);
555 }
556 assert(p == e, "bad memregion: doesn't end on obj boundary");
557 }
559 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
560 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
561 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
562 }
563 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
566 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) {
567 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
568 }
570 HeapWord*
571 HeapRegion::object_iterate_mem_careful(MemRegion mr,
572 ObjectClosure* cl) {
573 G1CollectedHeap* g1h = G1CollectedHeap::heap();
574 // We used to use "block_start_careful" here. But we're actually happy
575 // to update the BOT while we do this...
576 HeapWord* cur = block_start(mr.start());
577 mr = mr.intersection(used_region());
578 if (mr.is_empty()) return NULL;
579 // Otherwise, find the obj that extends onto mr.start().
581 assert(cur <= mr.start()
582 && (oop(cur)->klass_or_null() == NULL ||
583 cur + oop(cur)->size() > mr.start()),
584 "postcondition of block_start");
585 oop obj;
586 while (cur < mr.end()) {
587 obj = oop(cur);
588 if (obj->klass_or_null() == NULL) {
589 // Ran into an unparseable point.
590 return cur;
591 } else if (!g1h->is_obj_dead(obj)) {
592 cl->do_object(obj);
593 }
594 if (cl->abort()) return cur;
595 // The check above must occur before the operation below, since an
596 // abort might invalidate the "size" operation.
597 cur += obj->size();
598 }
599 return NULL;
600 }
602 HeapWord*
603 HeapRegion::
604 oops_on_card_seq_iterate_careful(MemRegion mr,
605 FilterOutOfRegionClosure* cl,
606 bool filter_young,
607 jbyte* card_ptr) {
608 // Currently, we should only have to clean the card if filter_young
609 // is true and vice versa.
610 if (filter_young) {
611 assert(card_ptr != NULL, "pre-condition");
612 } else {
613 assert(card_ptr == NULL, "pre-condition");
614 }
615 G1CollectedHeap* g1h = G1CollectedHeap::heap();
617 // If we're within a stop-world GC, then we might look at a card in a
618 // GC alloc region that extends onto a GC LAB, which may not be
619 // parseable. Stop such at the "saved_mark" of the region.
620 if (G1CollectedHeap::heap()->is_gc_active()) {
621 mr = mr.intersection(used_region_at_save_marks());
622 } else {
623 mr = mr.intersection(used_region());
624 }
625 if (mr.is_empty()) return NULL;
626 // Otherwise, find the obj that extends onto mr.start().
628 // The intersection of the incoming mr (for the card) and the
629 // allocated part of the region is non-empty. This implies that
630 // we have actually allocated into this region. The code in
631 // G1CollectedHeap.cpp that allocates a new region sets the
632 // is_young tag on the region before allocating. Thus we
633 // safely know if this region is young.
634 if (is_young() && filter_young) {
635 return NULL;
636 }
638 assert(!is_young(), "check value of filter_young");
640 // We can only clean the card here, after we make the decision that
641 // the card is not young. And we only clean the card if we have been
642 // asked to (i.e., card_ptr != NULL).
643 if (card_ptr != NULL) {
644 *card_ptr = CardTableModRefBS::clean_card_val();
645 // We must complete this write before we do any of the reads below.
646 OrderAccess::storeload();
647 }
649 // We used to use "block_start_careful" here. But we're actually happy
650 // to update the BOT while we do this...
651 HeapWord* cur = block_start(mr.start());
652 assert(cur <= mr.start(), "Postcondition");
654 while (cur <= mr.start()) {
655 if (oop(cur)->klass_or_null() == NULL) {
656 // Ran into an unparseable point.
657 return cur;
658 }
659 // Otherwise...
660 int sz = oop(cur)->size();
661 if (cur + sz > mr.start()) break;
662 // Otherwise, go on.
663 cur = cur + sz;
664 }
665 oop obj;
666 obj = oop(cur);
667 // If we finish this loop...
668 assert(cur <= mr.start()
669 && obj->klass_or_null() != NULL
670 && cur + obj->size() > mr.start(),
671 "Loop postcondition");
672 if (!g1h->is_obj_dead(obj)) {
673 obj->oop_iterate(cl, mr);
674 }
676 HeapWord* next;
677 while (cur < mr.end()) {
678 obj = oop(cur);
679 if (obj->klass_or_null() == NULL) {
680 // Ran into an unparseable point.
681 return cur;
682 };
683 // Otherwise:
684 next = (cur + obj->size());
685 if (!g1h->is_obj_dead(obj)) {
686 if (next < mr.end()) {
687 obj->oop_iterate(cl);
688 } else {
689 // this obj spans the boundary. If it's an array, stop at the
690 // boundary.
691 if (obj->is_objArray()) {
692 obj->oop_iterate(cl, mr);
693 } else {
694 obj->oop_iterate(cl);
695 }
696 }
697 }
698 cur = next;
699 }
700 return NULL;
701 }
703 void HeapRegion::print() const { print_on(gclog_or_tty); }
704 void HeapRegion::print_on(outputStream* st) const {
705 if (isHumongous()) {
706 if (startsHumongous())
707 st->print(" HS");
708 else
709 st->print(" HC");
710 } else {
711 st->print(" ");
712 }
713 if (in_collection_set())
714 st->print(" CS");
715 else
716 st->print(" ");
717 if (is_young())
718 st->print(is_survivor() ? " SU" : " Y ");
719 else
720 st->print(" ");
721 if (is_empty())
722 st->print(" F");
723 else
724 st->print(" ");
725 st->print(" %5d", _gc_time_stamp);
726 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
727 prev_top_at_mark_start(), next_top_at_mark_start());
728 G1OffsetTableContigSpace::print_on(st);
729 }
731 void HeapRegion::verify(bool allow_dirty) const {
732 bool dummy = false;
733 verify(allow_dirty, VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
734 }
736 // This really ought to be commoned up into OffsetTableContigSpace somehow.
737 // We would need a mechanism to make that code skip dead objects.
739 void HeapRegion::verify(bool allow_dirty,
740 VerifyOption vo,
741 bool* failures) const {
742 G1CollectedHeap* g1 = G1CollectedHeap::heap();
743 *failures = false;
744 HeapWord* p = bottom();
745 HeapWord* prev_p = NULL;
746 VerifyLiveClosure vl_cl(g1, vo);
747 bool is_humongous = isHumongous();
748 bool do_bot_verify = !is_young();
749 size_t object_num = 0;
750 while (p < top()) {
751 oop obj = oop(p);
752 size_t obj_size = obj->size();
753 object_num += 1;
755 if (is_humongous != g1->isHumongous(obj_size)) {
756 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
757 SIZE_FORMAT" words) in a %shumongous region",
758 p, g1->isHumongous(obj_size) ? "" : "non-",
759 obj_size, is_humongous ? "" : "non-");
760 *failures = true;
761 return;
762 }
764 // If it returns false, verify_for_object() will output the
765 // appropriate messasge.
766 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
767 *failures = true;
768 return;
769 }
771 if (!g1->is_obj_dead_cond(obj, this, vo)) {
772 if (obj->is_oop()) {
773 klassOop klass = obj->klass();
774 if (!klass->is_perm()) {
775 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
776 "not in perm", klass, obj);
777 *failures = true;
778 return;
779 } else if (!klass->is_klass()) {
780 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
781 "not a klass", klass, obj);
782 *failures = true;
783 return;
784 } else {
785 vl_cl.set_containing_obj(obj);
786 obj->oop_iterate(&vl_cl);
787 if (vl_cl.failures()) {
788 *failures = true;
789 }
790 if (G1MaxVerifyFailures >= 0 &&
791 vl_cl.n_failures() >= G1MaxVerifyFailures) {
792 return;
793 }
794 }
795 } else {
796 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
797 *failures = true;
798 return;
799 }
800 }
801 prev_p = p;
802 p += obj_size;
803 }
805 if (p != top()) {
806 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
807 "does not match top "PTR_FORMAT, p, top());
808 *failures = true;
809 return;
810 }
812 HeapWord* the_end = end();
813 assert(p == top(), "it should still hold");
814 // Do some extra BOT consistency checking for addresses in the
815 // range [top, end). BOT look-ups in this range should yield
816 // top. No point in doing that if top == end (there's nothing there).
817 if (p < the_end) {
818 // Look up top
819 HeapWord* addr_1 = p;
820 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
821 if (b_start_1 != p) {
822 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
823 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
824 addr_1, b_start_1, p);
825 *failures = true;
826 return;
827 }
829 // Look up top + 1
830 HeapWord* addr_2 = p + 1;
831 if (addr_2 < the_end) {
832 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
833 if (b_start_2 != p) {
834 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
835 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
836 addr_2, b_start_2, p);
837 *failures = true;
838 return;
839 }
840 }
842 // Look up an address between top and end
843 size_t diff = pointer_delta(the_end, p) / 2;
844 HeapWord* addr_3 = p + diff;
845 if (addr_3 < the_end) {
846 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
847 if (b_start_3 != p) {
848 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
849 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
850 addr_3, b_start_3, p);
851 *failures = true;
852 return;
853 }
854 }
856 // Loook up end - 1
857 HeapWord* addr_4 = the_end - 1;
858 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
859 if (b_start_4 != p) {
860 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
861 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
862 addr_4, b_start_4, p);
863 *failures = true;
864 return;
865 }
866 }
868 if (is_humongous && object_num > 1) {
869 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
870 "but has "SIZE_FORMAT", objects",
871 bottom(), end(), object_num);
872 *failures = true;
873 return;
874 }
875 }
877 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
878 // away eventually.
880 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
881 // false ==> we'll do the clearing if there's clearing to be done.
882 ContiguousSpace::initialize(mr, false, mangle_space);
883 _offsets.zero_bottom_entry();
884 _offsets.initialize_threshold();
885 if (clear_space) clear(mangle_space);
886 }
888 void G1OffsetTableContigSpace::clear(bool mangle_space) {
889 ContiguousSpace::clear(mangle_space);
890 _offsets.zero_bottom_entry();
891 _offsets.initialize_threshold();
892 }
894 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
895 Space::set_bottom(new_bottom);
896 _offsets.set_bottom(new_bottom);
897 }
899 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
900 Space::set_end(new_end);
901 _offsets.resize(new_end - bottom());
902 }
904 void G1OffsetTableContigSpace::print() const {
905 print_short();
906 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
907 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
908 bottom(), top(), _offsets.threshold(), end());
909 }
911 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
912 return _offsets.initialize_threshold();
913 }
915 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
916 HeapWord* end) {
917 _offsets.alloc_block(start, end);
918 return _offsets.threshold();
919 }
921 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
922 G1CollectedHeap* g1h = G1CollectedHeap::heap();
923 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
924 if (_gc_time_stamp < g1h->get_gc_time_stamp())
925 return top();
926 else
927 return ContiguousSpace::saved_mark_word();
928 }
930 void G1OffsetTableContigSpace::set_saved_mark() {
931 G1CollectedHeap* g1h = G1CollectedHeap::heap();
932 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
934 if (_gc_time_stamp < curr_gc_time_stamp) {
935 // The order of these is important, as another thread might be
936 // about to start scanning this region. If it does so after
937 // set_saved_mark and before _gc_time_stamp = ..., then the latter
938 // will be false, and it will pick up top() as the high water mark
939 // of region. If it does so after _gc_time_stamp = ..., then it
940 // will pick up the right saved_mark_word() as the high water mark
941 // of the region. Either way, the behaviour will be correct.
942 ContiguousSpace::set_saved_mark();
943 OrderAccess::storestore();
944 _gc_time_stamp = curr_gc_time_stamp;
945 // No need to do another barrier to flush the writes above. If
946 // this is called in parallel with other threads trying to
947 // allocate into the region, the caller should call this while
948 // holding a lock and when the lock is released the writes will be
949 // flushed.
950 }
951 }
953 G1OffsetTableContigSpace::
954 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
955 MemRegion mr, bool is_zeroed) :
956 _offsets(sharedOffsetArray, mr),
957 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
958 _gc_time_stamp(0)
959 {
960 _offsets.set_space(this);
961 initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
962 }