Fri, 17 May 2013 11:57:05 +0200
8014277: Remove ObjectClosure as base class for BoolObjectClosure
Reviewed-by: brutisso, tschatzl
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.
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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 *
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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.
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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, ExtendedOopClosure* cl,
44 CardTableModRefBS::PrecisionStyle precision,
45 FilterKind fk) :
46 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
47 _hr(hr), _fk(fk), _g1(g1) { }
49 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
50 OopClosure* oc) :
51 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
53 class VerifyLiveClosure: public OopClosure {
54 private:
55 G1CollectedHeap* _g1h;
56 CardTableModRefBS* _bs;
57 oop _containing_obj;
58 bool _failures;
59 int _n_failures;
60 VerifyOption _vo;
61 public:
62 // _vo == UsePrevMarking -> use "prev" marking information,
63 // _vo == UseNextMarking -> use "next" marking information,
64 // _vo == UseMarkWord -> use mark word from object header.
65 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
66 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
67 _failures(false), _n_failures(0), _vo(vo)
68 {
69 BarrierSet* bs = _g1h->barrier_set();
70 if (bs->is_a(BarrierSet::CardTableModRef))
71 _bs = (CardTableModRefBS*)bs;
72 }
74 void set_containing_obj(oop obj) {
75 _containing_obj = obj;
76 }
78 bool failures() { return _failures; }
79 int n_failures() { return _n_failures; }
81 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
82 virtual void do_oop( oop* p) { do_oop_work(p); }
84 void print_object(outputStream* out, oop obj) {
85 #ifdef PRODUCT
86 Klass* k = obj->klass();
87 const char* class_name = InstanceKlass::cast(k)->external_name();
88 out->print_cr("class name %s", class_name);
89 #else // PRODUCT
90 obj->print_on(out);
91 #endif // PRODUCT
92 }
94 template <class T>
95 void do_oop_work(T* p) {
96 assert(_containing_obj != NULL, "Precondition");
97 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
98 "Precondition");
99 T heap_oop = oopDesc::load_heap_oop(p);
100 if (!oopDesc::is_null(heap_oop)) {
101 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
102 bool failed = false;
103 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
104 MutexLockerEx x(ParGCRareEvent_lock,
105 Mutex::_no_safepoint_check_flag);
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 gclog_or_tty->flush();
137 _failures = true;
138 failed = true;
139 _n_failures++;
140 }
142 if (!_g1h->full_collection()) {
143 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
144 HeapRegion* to = _g1h->heap_region_containing(obj);
145 if (from != NULL && to != NULL &&
146 from != to &&
147 !to->isHumongous()) {
148 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
149 jbyte cv_field = *_bs->byte_for_const(p);
150 const jbyte dirty = CardTableModRefBS::dirty_card_val();
152 bool is_bad = !(from->is_young()
153 || to->rem_set()->contains_reference(p)
154 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
155 (_containing_obj->is_objArray() ?
156 cv_field == dirty
157 : cv_obj == dirty || cv_field == dirty));
158 if (is_bad) {
159 MutexLockerEx x(ParGCRareEvent_lock,
160 Mutex::_no_safepoint_check_flag);
162 if (!_failures) {
163 gclog_or_tty->print_cr("");
164 gclog_or_tty->print_cr("----------");
165 }
166 gclog_or_tty->print_cr("Missing rem set entry:");
167 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
168 "of obj "PTR_FORMAT", "
169 "in region "HR_FORMAT,
170 p, (void*) _containing_obj,
171 HR_FORMAT_PARAMS(from));
172 _containing_obj->print_on(gclog_or_tty);
173 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
174 "in region "HR_FORMAT,
175 (void*) obj,
176 HR_FORMAT_PARAMS(to));
177 obj->print_on(gclog_or_tty);
178 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
179 cv_obj, cv_field);
180 gclog_or_tty->print_cr("----------");
181 gclog_or_tty->flush();
182 _failures = true;
183 if (!failed) _n_failures++;
184 }
185 }
186 }
187 }
188 }
189 };
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 }
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;
221 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
222 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
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 }
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 }
241 bottom += oop_size;
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;
250 case IntoCSFilterKind: {
251 FilterIntoCSClosure filt(this, g1h, cl);
252 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
253 break;
254 }
256 case OutOfRegionFilterKind: {
257 FilterOutOfRegionClosure filt(_hr, cl);
258 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
259 break;
260 }
262 default:
263 ShouldNotReachHere();
264 }
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 }
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 )
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 )
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
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.
300 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
301 (uintx) MIN_REGION_SIZE);
302 }
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);
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 }
317 // And recalculate the log.
318 region_size_log = log2_long((jlong) region_size);
320 // Now, set up the globals.
321 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
322 LogOfHRGrainBytes = region_size_log;
324 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
325 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
327 guarantee(GrainBytes == 0, "we should only set it once");
328 // The cast to int is safe, given that we've bounded region_size by
329 // MIN_REGION_SIZE and MAX_REGION_SIZE.
330 GrainBytes = (size_t)region_size;
332 guarantee(GrainWords == 0, "we should only set it once");
333 GrainWords = GrainBytes >> LogHeapWordSize;
334 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
336 guarantee(CardsPerRegion == 0, "we should only set it once");
337 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
338 }
340 void HeapRegion::reset_after_compaction() {
341 G1OffsetTableContigSpace::reset_after_compaction();
342 // After a compaction the mark bitmap is invalid, so we must
343 // treat all objects as being inside the unmarked area.
344 zero_marked_bytes();
345 init_top_at_mark_start();
346 }
348 void HeapRegion::hr_clear(bool par, bool clear_space) {
349 assert(_humongous_type == NotHumongous,
350 "we should have already filtered out humongous regions");
351 assert(_humongous_start_region == NULL,
352 "we should have already filtered out humongous regions");
353 assert(_end == _orig_end,
354 "we should have already filtered out humongous regions");
356 _in_collection_set = false;
358 set_young_index_in_cset(-1);
359 uninstall_surv_rate_group();
360 set_young_type(NotYoung);
361 reset_pre_dummy_top();
363 if (!par) {
364 // If this is parallel, this will be done later.
365 HeapRegionRemSet* hrrs = rem_set();
366 if (hrrs != NULL) hrrs->clear();
367 _claimed = InitialClaimValue;
368 }
369 zero_marked_bytes();
371 _offsets.resize(HeapRegion::GrainWords);
372 init_top_at_mark_start();
373 if (clear_space) clear(SpaceDecorator::Mangle);
374 }
376 void HeapRegion::par_clear() {
377 assert(used() == 0, "the region should have been already cleared");
378 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
379 HeapRegionRemSet* hrrs = rem_set();
380 hrrs->clear();
381 CardTableModRefBS* ct_bs =
382 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
383 ct_bs->clear(MemRegion(bottom(), end()));
384 }
386 void HeapRegion::calc_gc_efficiency() {
387 // GC efficiency is the ratio of how much space would be
388 // reclaimed over how long we predict it would take to reclaim it.
389 G1CollectedHeap* g1h = G1CollectedHeap::heap();
390 G1CollectorPolicy* g1p = g1h->g1_policy();
392 // Retrieve a prediction of the elapsed time for this region for
393 // a mixed gc because the region will only be evacuated during a
394 // mixed gc.
395 double region_elapsed_time_ms =
396 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
397 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
398 }
400 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
401 assert(!isHumongous(), "sanity / pre-condition");
402 assert(end() == _orig_end,
403 "Should be normal before the humongous object allocation");
404 assert(top() == bottom(), "should be empty");
405 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
407 _humongous_type = StartsHumongous;
408 _humongous_start_region = this;
410 set_end(new_end);
411 _offsets.set_for_starts_humongous(new_top);
412 }
414 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
415 assert(!isHumongous(), "sanity / pre-condition");
416 assert(end() == _orig_end,
417 "Should be normal before the humongous object allocation");
418 assert(top() == bottom(), "should be empty");
419 assert(first_hr->startsHumongous(), "pre-condition");
421 _humongous_type = ContinuesHumongous;
422 _humongous_start_region = first_hr;
423 }
425 void HeapRegion::set_notHumongous() {
426 assert(isHumongous(), "pre-condition");
428 if (startsHumongous()) {
429 assert(top() <= end(), "pre-condition");
430 set_end(_orig_end);
431 if (top() > end()) {
432 // at least one "continues humongous" region after it
433 set_top(end());
434 }
435 } else {
436 // continues humongous
437 assert(end() == _orig_end, "sanity");
438 }
440 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
441 _humongous_type = NotHumongous;
442 _humongous_start_region = NULL;
443 }
445 bool HeapRegion::claimHeapRegion(jint claimValue) {
446 jint current = _claimed;
447 if (current != claimValue) {
448 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
449 if (res == current) {
450 return true;
451 }
452 }
453 return false;
454 }
456 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
457 HeapWord* low = addr;
458 HeapWord* high = end();
459 while (low < high) {
460 size_t diff = pointer_delta(high, low);
461 // Must add one below to bias toward the high amount. Otherwise, if
462 // "high" were at the desired value, and "low" were one less, we
463 // would not converge on "high". This is not symmetric, because
464 // we set "high" to a block start, which might be the right one,
465 // which we don't do for "low".
466 HeapWord* middle = low + (diff+1)/2;
467 if (middle == high) return high;
468 HeapWord* mid_bs = block_start_careful(middle);
469 if (mid_bs < addr) {
470 low = middle;
471 } else {
472 high = mid_bs;
473 }
474 }
475 assert(low == high && low >= addr, "Didn't work.");
476 return low;
477 }
479 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
480 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
481 #endif // _MSC_VER
484 HeapRegion::HeapRegion(uint hrs_index,
485 G1BlockOffsetSharedArray* sharedOffsetArray,
486 MemRegion mr) :
487 G1OffsetTableContigSpace(sharedOffsetArray, mr),
488 _hrs_index(hrs_index),
489 _humongous_type(NotHumongous), _humongous_start_region(NULL),
490 _in_collection_set(false),
491 _next_in_special_set(NULL), _orig_end(NULL),
492 _claimed(InitialClaimValue), _evacuation_failed(false),
493 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
494 _young_type(NotYoung), _next_young_region(NULL),
495 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
496 #ifdef ASSERT
497 _containing_set(NULL),
498 #endif // ASSERT
499 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
500 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
501 _predicted_bytes_to_copy(0)
502 {
503 _orig_end = mr.end();
504 // Note that initialize() will set the start of the unmarked area of the
505 // region.
506 hr_clear(false /*par*/, false /*clear_space*/);
507 set_top(bottom());
508 set_saved_mark();
510 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
512 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
513 }
515 CompactibleSpace* HeapRegion::next_compaction_space() const {
516 // We're not using an iterator given that it will wrap around when
517 // it reaches the last region and this is not what we want here.
518 G1CollectedHeap* g1h = G1CollectedHeap::heap();
519 uint index = hrs_index() + 1;
520 while (index < g1h->n_regions()) {
521 HeapRegion* hr = g1h->region_at(index);
522 if (!hr->isHumongous()) {
523 return hr;
524 }
525 index += 1;
526 }
527 return NULL;
528 }
530 void HeapRegion::save_marks() {
531 set_saved_mark();
532 }
534 void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
535 HeapWord* p = mr.start();
536 HeapWord* e = mr.end();
537 oop obj;
538 while (p < e) {
539 obj = oop(p);
540 p += obj->oop_iterate(cl);
541 }
542 assert(p == e, "bad memregion: doesn't end on obj boundary");
543 }
545 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
546 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
547 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
548 }
549 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
552 void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
553 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
554 }
556 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
557 bool during_conc_mark) {
558 // We always recreate the prev marking info and we'll explicitly
559 // mark all objects we find to be self-forwarded on the prev
560 // bitmap. So all objects need to be below PTAMS.
561 _prev_top_at_mark_start = top();
562 _prev_marked_bytes = 0;
564 if (during_initial_mark) {
565 // During initial-mark, we'll also explicitly mark all objects
566 // we find to be self-forwarded on the next bitmap. So all
567 // objects need to be below NTAMS.
568 _next_top_at_mark_start = top();
569 _next_marked_bytes = 0;
570 } else if (during_conc_mark) {
571 // During concurrent mark, all objects in the CSet (including
572 // the ones we find to be self-forwarded) are implicitly live.
573 // So all objects need to be above NTAMS.
574 _next_top_at_mark_start = bottom();
575 _next_marked_bytes = 0;
576 }
577 }
579 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
580 bool during_conc_mark,
581 size_t marked_bytes) {
582 assert(0 <= marked_bytes && marked_bytes <= used(),
583 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
584 marked_bytes, used()));
585 _prev_marked_bytes = marked_bytes;
586 }
588 HeapWord*
589 HeapRegion::object_iterate_mem_careful(MemRegion mr,
590 ObjectClosure* cl) {
591 G1CollectedHeap* g1h = G1CollectedHeap::heap();
592 // We used to use "block_start_careful" here. But we're actually happy
593 // to update the BOT while we do this...
594 HeapWord* cur = block_start(mr.start());
595 mr = mr.intersection(used_region());
596 if (mr.is_empty()) return NULL;
597 // Otherwise, find the obj that extends onto mr.start().
599 assert(cur <= mr.start()
600 && (oop(cur)->klass_or_null() == NULL ||
601 cur + oop(cur)->size() > mr.start()),
602 "postcondition of block_start");
603 oop obj;
604 while (cur < mr.end()) {
605 obj = oop(cur);
606 if (obj->klass_or_null() == NULL) {
607 // Ran into an unparseable point.
608 return cur;
609 } else if (!g1h->is_obj_dead(obj)) {
610 cl->do_object(obj);
611 }
612 if (cl->abort()) return cur;
613 // The check above must occur before the operation below, since an
614 // abort might invalidate the "size" operation.
615 cur += obj->size();
616 }
617 return NULL;
618 }
620 HeapWord*
621 HeapRegion::
622 oops_on_card_seq_iterate_careful(MemRegion mr,
623 FilterOutOfRegionClosure* cl,
624 bool filter_young,
625 jbyte* card_ptr) {
626 // Currently, we should only have to clean the card if filter_young
627 // is true and vice versa.
628 if (filter_young) {
629 assert(card_ptr != NULL, "pre-condition");
630 } else {
631 assert(card_ptr == NULL, "pre-condition");
632 }
633 G1CollectedHeap* g1h = G1CollectedHeap::heap();
635 // If we're within a stop-world GC, then we might look at a card in a
636 // GC alloc region that extends onto a GC LAB, which may not be
637 // parseable. Stop such at the "saved_mark" of the region.
638 if (g1h->is_gc_active()) {
639 mr = mr.intersection(used_region_at_save_marks());
640 } else {
641 mr = mr.intersection(used_region());
642 }
643 if (mr.is_empty()) return NULL;
644 // Otherwise, find the obj that extends onto mr.start().
646 // The intersection of the incoming mr (for the card) and the
647 // allocated part of the region is non-empty. This implies that
648 // we have actually allocated into this region. The code in
649 // G1CollectedHeap.cpp that allocates a new region sets the
650 // is_young tag on the region before allocating. Thus we
651 // safely know if this region is young.
652 if (is_young() && filter_young) {
653 return NULL;
654 }
656 assert(!is_young(), "check value of filter_young");
658 // We can only clean the card here, after we make the decision that
659 // the card is not young. And we only clean the card if we have been
660 // asked to (i.e., card_ptr != NULL).
661 if (card_ptr != NULL) {
662 *card_ptr = CardTableModRefBS::clean_card_val();
663 // We must complete this write before we do any of the reads below.
664 OrderAccess::storeload();
665 }
667 // Cache the boundaries of the memory region in some const locals
668 HeapWord* const start = mr.start();
669 HeapWord* const end = mr.end();
671 // We used to use "block_start_careful" here. But we're actually happy
672 // to update the BOT while we do this...
673 HeapWord* cur = block_start(start);
674 assert(cur <= start, "Postcondition");
676 oop obj;
678 HeapWord* next = cur;
679 while (next <= start) {
680 cur = next;
681 obj = oop(cur);
682 if (obj->klass_or_null() == NULL) {
683 // Ran into an unparseable point.
684 return cur;
685 }
686 // Otherwise...
687 next = (cur + obj->size());
688 }
690 // If we finish the above loop...We have a parseable object that
691 // begins on or before the start of the memory region, and ends
692 // inside or spans the entire region.
694 assert(obj == oop(cur), "sanity");
695 assert(cur <= start &&
696 obj->klass_or_null() != NULL &&
697 (cur + obj->size()) > start,
698 "Loop postcondition");
700 if (!g1h->is_obj_dead(obj)) {
701 obj->oop_iterate(cl, mr);
702 }
704 while (cur < end) {
705 obj = oop(cur);
706 if (obj->klass_or_null() == NULL) {
707 // Ran into an unparseable point.
708 return cur;
709 };
711 // Otherwise:
712 next = (cur + obj->size());
714 if (!g1h->is_obj_dead(obj)) {
715 if (next < end || !obj->is_objArray()) {
716 // This object either does not span the MemRegion
717 // boundary, or if it does it's not an array.
718 // Apply closure to whole object.
719 obj->oop_iterate(cl);
720 } else {
721 // This obj is an array that spans the boundary.
722 // Stop at the boundary.
723 obj->oop_iterate(cl, mr);
724 }
725 }
726 cur = next;
727 }
728 return NULL;
729 }
731 void HeapRegion::print() const { print_on(gclog_or_tty); }
732 void HeapRegion::print_on(outputStream* st) const {
733 if (isHumongous()) {
734 if (startsHumongous())
735 st->print(" HS");
736 else
737 st->print(" HC");
738 } else {
739 st->print(" ");
740 }
741 if (in_collection_set())
742 st->print(" CS");
743 else
744 st->print(" ");
745 if (is_young())
746 st->print(is_survivor() ? " SU" : " Y ");
747 else
748 st->print(" ");
749 if (is_empty())
750 st->print(" F");
751 else
752 st->print(" ");
753 st->print(" TS %5d", _gc_time_stamp);
754 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
755 prev_top_at_mark_start(), next_top_at_mark_start());
756 G1OffsetTableContigSpace::print_on(st);
757 }
759 void HeapRegion::verify() const {
760 bool dummy = false;
761 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
762 }
764 // This really ought to be commoned up into OffsetTableContigSpace somehow.
765 // We would need a mechanism to make that code skip dead objects.
767 void HeapRegion::verify(VerifyOption vo,
768 bool* failures) const {
769 G1CollectedHeap* g1 = G1CollectedHeap::heap();
770 *failures = false;
771 HeapWord* p = bottom();
772 HeapWord* prev_p = NULL;
773 VerifyLiveClosure vl_cl(g1, vo);
774 bool is_humongous = isHumongous();
775 bool do_bot_verify = !is_young();
776 size_t object_num = 0;
777 while (p < top()) {
778 oop obj = oop(p);
779 size_t obj_size = obj->size();
780 object_num += 1;
782 if (is_humongous != g1->isHumongous(obj_size)) {
783 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
784 SIZE_FORMAT" words) in a %shumongous region",
785 p, g1->isHumongous(obj_size) ? "" : "non-",
786 obj_size, is_humongous ? "" : "non-");
787 *failures = true;
788 return;
789 }
791 // If it returns false, verify_for_object() will output the
792 // appropriate messasge.
793 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
794 *failures = true;
795 return;
796 }
798 if (!g1->is_obj_dead_cond(obj, this, vo)) {
799 if (obj->is_oop()) {
800 Klass* klass = obj->klass();
801 if (!klass->is_metadata()) {
802 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
803 "not metadata", klass, obj);
804 *failures = true;
805 return;
806 } else if (!klass->is_klass()) {
807 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
808 "not a klass", klass, obj);
809 *failures = true;
810 return;
811 } else {
812 vl_cl.set_containing_obj(obj);
813 obj->oop_iterate_no_header(&vl_cl);
814 if (vl_cl.failures()) {
815 *failures = true;
816 }
817 if (G1MaxVerifyFailures >= 0 &&
818 vl_cl.n_failures() >= G1MaxVerifyFailures) {
819 return;
820 }
821 }
822 } else {
823 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
824 *failures = true;
825 return;
826 }
827 }
828 prev_p = p;
829 p += obj_size;
830 }
832 if (p != top()) {
833 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
834 "does not match top "PTR_FORMAT, p, top());
835 *failures = true;
836 return;
837 }
839 HeapWord* the_end = end();
840 assert(p == top(), "it should still hold");
841 // Do some extra BOT consistency checking for addresses in the
842 // range [top, end). BOT look-ups in this range should yield
843 // top. No point in doing that if top == end (there's nothing there).
844 if (p < the_end) {
845 // Look up top
846 HeapWord* addr_1 = p;
847 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
848 if (b_start_1 != p) {
849 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
850 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
851 addr_1, b_start_1, p);
852 *failures = true;
853 return;
854 }
856 // Look up top + 1
857 HeapWord* addr_2 = p + 1;
858 if (addr_2 < the_end) {
859 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
860 if (b_start_2 != p) {
861 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
862 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
863 addr_2, b_start_2, p);
864 *failures = true;
865 return;
866 }
867 }
869 // Look up an address between top and end
870 size_t diff = pointer_delta(the_end, p) / 2;
871 HeapWord* addr_3 = p + diff;
872 if (addr_3 < the_end) {
873 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
874 if (b_start_3 != p) {
875 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
876 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
877 addr_3, b_start_3, p);
878 *failures = true;
879 return;
880 }
881 }
883 // Loook up end - 1
884 HeapWord* addr_4 = the_end - 1;
885 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
886 if (b_start_4 != p) {
887 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
888 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
889 addr_4, b_start_4, p);
890 *failures = true;
891 return;
892 }
893 }
895 if (is_humongous && object_num > 1) {
896 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
897 "but has "SIZE_FORMAT", objects",
898 bottom(), end(), object_num);
899 *failures = true;
900 return;
901 }
902 }
904 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
905 // away eventually.
907 void G1OffsetTableContigSpace::clear(bool mangle_space) {
908 ContiguousSpace::clear(mangle_space);
909 _offsets.zero_bottom_entry();
910 _offsets.initialize_threshold();
911 }
913 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
914 Space::set_bottom(new_bottom);
915 _offsets.set_bottom(new_bottom);
916 }
918 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
919 Space::set_end(new_end);
920 _offsets.resize(new_end - bottom());
921 }
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 }
930 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
931 return _offsets.initialize_threshold();
932 }
934 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
935 HeapWord* end) {
936 _offsets.alloc_block(start, end);
937 return _offsets.threshold();
938 }
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 }
949 void G1OffsetTableContigSpace::set_saved_mark() {
950 G1CollectedHeap* g1h = G1CollectedHeap::heap();
951 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
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 }
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 }