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src/share/vm/gc_implementation/g1/heapRegion.cpp@c49dcaf78a65
src/share/vm/gc_implementation/g1/heapRegion.cpp
Thu, 08 May 2014 15:37:17 +0200
- author
- goetz
- date
- Thu, 08 May 2014 15:37:17 +0200
- changeset 6912
- c49dcaf78a65
- parent 6911
- ce8f6bb717c9
- child 6986
- e635a728f9da
- permissions
- -rw-r--r--
8042737: Introduce umbrella header prefetch.inline.hpp
Reviewed-by: twisti, stefank
1 /*
2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
30 #include "gc_implementation/g1/heapRegion.inline.hpp"
31 #include "gc_implementation/g1/heapRegionRemSet.hpp"
32 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
33 #include "memory/genOopClosures.inline.hpp"
34 #include "memory/iterator.hpp"
35 #include "memory/space.inline.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "runtime/orderAccess.inline.hpp"
39 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
41 int HeapRegion::LogOfHRGrainBytes = 0;
42 int HeapRegion::LogOfHRGrainWords = 0;
43 size_t HeapRegion::GrainBytes = 0;
44 size_t HeapRegion::GrainWords = 0;
45 size_t HeapRegion::CardsPerRegion = 0;
47 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
48 HeapRegion* hr, ExtendedOopClosure* cl,
49 CardTableModRefBS::PrecisionStyle precision,
50 FilterKind fk) :
51 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
52 _hr(hr), _fk(fk), _g1(g1) { }
54 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
55 OopClosure* oc) :
56 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
58 template<class ClosureType>
59 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
60 HeapRegion* hr,
61 HeapWord* cur, HeapWord* top) {
62 oop cur_oop = oop(cur);
63 int oop_size = cur_oop->size();
64 HeapWord* next_obj = cur + oop_size;
65 while (next_obj < top) {
66 // Keep filtering the remembered set.
67 if (!g1h->is_obj_dead(cur_oop, hr)) {
68 // Bottom lies entirely below top, so we can call the
69 // non-memRegion version of oop_iterate below.
70 cur_oop->oop_iterate(cl);
71 }
72 cur = next_obj;
73 cur_oop = oop(cur);
74 oop_size = cur_oop->size();
75 next_obj = cur + oop_size;
76 }
77 return cur;
78 }
80 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
81 HeapWord* bottom,
82 HeapWord* top,
83 ExtendedOopClosure* cl) {
84 G1CollectedHeap* g1h = _g1;
85 int oop_size;
86 ExtendedOopClosure* cl2 = NULL;
88 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
89 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
91 switch (_fk) {
92 case NoFilterKind: cl2 = cl; break;
93 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
94 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
95 default: ShouldNotReachHere();
96 }
98 // Start filtering what we add to the remembered set. If the object is
99 // not considered dead, either because it is marked (in the mark bitmap)
100 // or it was allocated after marking finished, then we add it. Otherwise
101 // we can safely ignore the object.
102 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
103 oop_size = oop(bottom)->oop_iterate(cl2, mr);
104 } else {
105 oop_size = oop(bottom)->size();
106 }
108 bottom += oop_size;
110 if (bottom < top) {
111 // We replicate the loop below for several kinds of possible filters.
112 switch (_fk) {
113 case NoFilterKind:
114 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
115 break;
117 case IntoCSFilterKind: {
118 FilterIntoCSClosure filt(this, g1h, cl);
119 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
120 break;
121 }
123 case OutOfRegionFilterKind: {
124 FilterOutOfRegionClosure filt(_hr, cl);
125 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
126 break;
127 }
129 default:
130 ShouldNotReachHere();
131 }
133 // Last object. Need to do dead-obj filtering here too.
134 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
135 oop(bottom)->oop_iterate(cl2, mr);
136 }
137 }
138 }
140 // Minimum region size; we won't go lower than that.
141 // We might want to decrease this in the future, to deal with small
142 // heaps a bit more efficiently.
143 #define MIN_REGION_SIZE ( 1024 * 1024 )
145 // Maximum region size; we don't go higher than that. There's a good
146 // reason for having an upper bound. We don't want regions to get too
147 // large, otherwise cleanup's effectiveness would decrease as there
148 // will be fewer opportunities to find totally empty regions after
149 // marking.
150 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
152 // The automatic region size calculation will try to have around this
153 // many regions in the heap (based on the min heap size).
154 #define TARGET_REGION_NUMBER 2048
156 size_t HeapRegion::max_region_size() {
157 return (size_t)MAX_REGION_SIZE;
158 }
160 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
161 uintx region_size = G1HeapRegionSize;
162 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
163 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
164 region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
165 (uintx) MIN_REGION_SIZE);
166 }
168 int region_size_log = log2_long((jlong) region_size);
169 // Recalculate the region size to make sure it's a power of
170 // 2. This means that region_size is the largest power of 2 that's
171 // <= what we've calculated so far.
172 region_size = ((uintx)1 << region_size_log);
174 // Now make sure that we don't go over or under our limits.
175 if (region_size < MIN_REGION_SIZE) {
176 region_size = MIN_REGION_SIZE;
177 } else if (region_size > MAX_REGION_SIZE) {
178 region_size = MAX_REGION_SIZE;
179 }
181 // And recalculate the log.
182 region_size_log = log2_long((jlong) region_size);
184 // Now, set up the globals.
185 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
186 LogOfHRGrainBytes = region_size_log;
188 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
189 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
191 guarantee(GrainBytes == 0, "we should only set it once");
192 // The cast to int is safe, given that we've bounded region_size by
193 // MIN_REGION_SIZE and MAX_REGION_SIZE.
194 GrainBytes = (size_t)region_size;
196 guarantee(GrainWords == 0, "we should only set it once");
197 GrainWords = GrainBytes >> LogHeapWordSize;
198 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
200 guarantee(CardsPerRegion == 0, "we should only set it once");
201 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
202 }
204 void HeapRegion::reset_after_compaction() {
205 G1OffsetTableContigSpace::reset_after_compaction();
206 // After a compaction the mark bitmap is invalid, so we must
207 // treat all objects as being inside the unmarked area.
208 zero_marked_bytes();
209 init_top_at_mark_start();
210 }
212 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
213 assert(_humongous_type == NotHumongous,
214 "we should have already filtered out humongous regions");
215 assert(_humongous_start_region == NULL,
216 "we should have already filtered out humongous regions");
217 assert(_end == _orig_end,
218 "we should have already filtered out humongous regions");
220 _in_collection_set = false;
222 set_young_index_in_cset(-1);
223 uninstall_surv_rate_group();
224 set_young_type(NotYoung);
225 reset_pre_dummy_top();
227 if (!par) {
228 // If this is parallel, this will be done later.
229 HeapRegionRemSet* hrrs = rem_set();
230 if (locked) {
231 hrrs->clear_locked();
232 } else {
233 hrrs->clear();
234 }
235 _claimed = InitialClaimValue;
236 }
237 zero_marked_bytes();
239 _offsets.resize(HeapRegion::GrainWords);
240 init_top_at_mark_start();
241 if (clear_space) clear(SpaceDecorator::Mangle);
242 }
244 void HeapRegion::par_clear() {
245 assert(used() == 0, "the region should have been already cleared");
246 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
247 HeapRegionRemSet* hrrs = rem_set();
248 hrrs->clear();
249 CardTableModRefBS* ct_bs =
250 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
251 ct_bs->clear(MemRegion(bottom(), end()));
252 }
254 void HeapRegion::calc_gc_efficiency() {
255 // GC efficiency is the ratio of how much space would be
256 // reclaimed over how long we predict it would take to reclaim it.
257 G1CollectedHeap* g1h = G1CollectedHeap::heap();
258 G1CollectorPolicy* g1p = g1h->g1_policy();
260 // Retrieve a prediction of the elapsed time for this region for
261 // a mixed gc because the region will only be evacuated during a
262 // mixed gc.
263 double region_elapsed_time_ms =
264 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
265 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
266 }
268 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
269 assert(!isHumongous(), "sanity / pre-condition");
270 assert(end() == _orig_end,
271 "Should be normal before the humongous object allocation");
272 assert(top() == bottom(), "should be empty");
273 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
275 _humongous_type = StartsHumongous;
276 _humongous_start_region = this;
278 set_end(new_end);
279 _offsets.set_for_starts_humongous(new_top);
280 }
282 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
283 assert(!isHumongous(), "sanity / pre-condition");
284 assert(end() == _orig_end,
285 "Should be normal before the humongous object allocation");
286 assert(top() == bottom(), "should be empty");
287 assert(first_hr->startsHumongous(), "pre-condition");
289 _humongous_type = ContinuesHumongous;
290 _humongous_start_region = first_hr;
291 }
293 void HeapRegion::set_notHumongous() {
294 assert(isHumongous(), "pre-condition");
296 if (startsHumongous()) {
297 assert(top() <= end(), "pre-condition");
298 set_end(_orig_end);
299 if (top() > end()) {
300 // at least one "continues humongous" region after it
301 set_top(end());
302 }
303 } else {
304 // continues humongous
305 assert(end() == _orig_end, "sanity");
306 }
308 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
309 _humongous_type = NotHumongous;
310 _humongous_start_region = NULL;
311 }
313 bool HeapRegion::claimHeapRegion(jint claimValue) {
314 jint current = _claimed;
315 if (current != claimValue) {
316 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
317 if (res == current) {
318 return true;
319 }
320 }
321 return false;
322 }
324 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
325 HeapWord* low = addr;
326 HeapWord* high = end();
327 while (low < high) {
328 size_t diff = pointer_delta(high, low);
329 // Must add one below to bias toward the high amount. Otherwise, if
330 // "high" were at the desired value, and "low" were one less, we
331 // would not converge on "high". This is not symmetric, because
332 // we set "high" to a block start, which might be the right one,
333 // which we don't do for "low".
334 HeapWord* middle = low + (diff+1)/2;
335 if (middle == high) return high;
336 HeapWord* mid_bs = block_start_careful(middle);
337 if (mid_bs < addr) {
338 low = middle;
339 } else {
340 high = mid_bs;
341 }
342 }
343 assert(low == high && low >= addr, "Didn't work.");
344 return low;
345 }
347 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
348 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
349 #endif // _MSC_VER
352 HeapRegion::HeapRegion(uint hrs_index,
353 G1BlockOffsetSharedArray* sharedOffsetArray,
354 MemRegion mr) :
355 G1OffsetTableContigSpace(sharedOffsetArray, mr),
356 _hrs_index(hrs_index),
357 _humongous_type(NotHumongous), _humongous_start_region(NULL),
358 _in_collection_set(false),
359 _next_in_special_set(NULL), _orig_end(NULL),
360 _claimed(InitialClaimValue), _evacuation_failed(false),
361 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
362 _young_type(NotYoung), _next_young_region(NULL),
363 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), _pending_removal(false),
364 #ifdef ASSERT
365 _containing_set(NULL),
366 #endif // ASSERT
367 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
368 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
369 _predicted_bytes_to_copy(0)
370 {
371 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
372 _orig_end = mr.end();
373 // Note that initialize() will set the start of the unmarked area of the
374 // region.
375 hr_clear(false /*par*/, false /*clear_space*/);
376 set_top(bottom());
377 set_saved_mark();
379 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
380 }
382 CompactibleSpace* HeapRegion::next_compaction_space() const {
383 // We're not using an iterator given that it will wrap around when
384 // it reaches the last region and this is not what we want here.
385 G1CollectedHeap* g1h = G1CollectedHeap::heap();
386 uint index = hrs_index() + 1;
387 while (index < g1h->n_regions()) {
388 HeapRegion* hr = g1h->region_at(index);
389 if (!hr->isHumongous()) {
390 return hr;
391 }
392 index += 1;
393 }
394 return NULL;
395 }
397 void HeapRegion::save_marks() {
398 set_saved_mark();
399 }
401 void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
402 HeapWord* p = mr.start();
403 HeapWord* e = mr.end();
404 oop obj;
405 while (p < e) {
406 obj = oop(p);
407 p += obj->oop_iterate(cl);
408 }
409 assert(p == e, "bad memregion: doesn't end on obj boundary");
410 }
412 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
413 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
414 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
415 }
416 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
419 void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
420 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
421 }
423 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
424 bool during_conc_mark) {
425 // We always recreate the prev marking info and we'll explicitly
426 // mark all objects we find to be self-forwarded on the prev
427 // bitmap. So all objects need to be below PTAMS.
428 _prev_top_at_mark_start = top();
429 _prev_marked_bytes = 0;
431 if (during_initial_mark) {
432 // During initial-mark, we'll also explicitly mark all objects
433 // we find to be self-forwarded on the next bitmap. So all
434 // objects need to be below NTAMS.
435 _next_top_at_mark_start = top();
436 _next_marked_bytes = 0;
437 } else if (during_conc_mark) {
438 // During concurrent mark, all objects in the CSet (including
439 // the ones we find to be self-forwarded) are implicitly live.
440 // So all objects need to be above NTAMS.
441 _next_top_at_mark_start = bottom();
442 _next_marked_bytes = 0;
443 }
444 }
446 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
447 bool during_conc_mark,
448 size_t marked_bytes) {
449 assert(0 <= marked_bytes && marked_bytes <= used(),
450 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
451 marked_bytes, used()));
452 _prev_marked_bytes = marked_bytes;
453 }
455 HeapWord*
456 HeapRegion::object_iterate_mem_careful(MemRegion mr,
457 ObjectClosure* cl) {
458 G1CollectedHeap* g1h = G1CollectedHeap::heap();
459 // We used to use "block_start_careful" here. But we're actually happy
460 // to update the BOT while we do this...
461 HeapWord* cur = block_start(mr.start());
462 mr = mr.intersection(used_region());
463 if (mr.is_empty()) return NULL;
464 // Otherwise, find the obj that extends onto mr.start().
466 assert(cur <= mr.start()
467 && (oop(cur)->klass_or_null() == NULL ||
468 cur + oop(cur)->size() > mr.start()),
469 "postcondition of block_start");
470 oop obj;
471 while (cur < mr.end()) {
472 obj = oop(cur);
473 if (obj->klass_or_null() == NULL) {
474 // Ran into an unparseable point.
475 return cur;
476 } else if (!g1h->is_obj_dead(obj)) {
477 cl->do_object(obj);
478 }
479 if (cl->abort()) return cur;
480 // The check above must occur before the operation below, since an
481 // abort might invalidate the "size" operation.
482 cur += obj->size();
483 }
484 return NULL;
485 }
487 HeapWord*
488 HeapRegion::
489 oops_on_card_seq_iterate_careful(MemRegion mr,
490 FilterOutOfRegionClosure* cl,
491 bool filter_young,
492 jbyte* card_ptr) {
493 // Currently, we should only have to clean the card if filter_young
494 // is true and vice versa.
495 if (filter_young) {
496 assert(card_ptr != NULL, "pre-condition");
497 } else {
498 assert(card_ptr == NULL, "pre-condition");
499 }
500 G1CollectedHeap* g1h = G1CollectedHeap::heap();
502 // If we're within a stop-world GC, then we might look at a card in a
503 // GC alloc region that extends onto a GC LAB, which may not be
504 // parseable. Stop such at the "saved_mark" of the region.
505 if (g1h->is_gc_active()) {
506 mr = mr.intersection(used_region_at_save_marks());
507 } else {
508 mr = mr.intersection(used_region());
509 }
510 if (mr.is_empty()) return NULL;
511 // Otherwise, find the obj that extends onto mr.start().
513 // The intersection of the incoming mr (for the card) and the
514 // allocated part of the region is non-empty. This implies that
515 // we have actually allocated into this region. The code in
516 // G1CollectedHeap.cpp that allocates a new region sets the
517 // is_young tag on the region before allocating. Thus we
518 // safely know if this region is young.
519 if (is_young() && filter_young) {
520 return NULL;
521 }
523 assert(!is_young(), "check value of filter_young");
525 // We can only clean the card here, after we make the decision that
526 // the card is not young. And we only clean the card if we have been
527 // asked to (i.e., card_ptr != NULL).
528 if (card_ptr != NULL) {
529 *card_ptr = CardTableModRefBS::clean_card_val();
530 // We must complete this write before we do any of the reads below.
531 OrderAccess::storeload();
532 }
534 // Cache the boundaries of the memory region in some const locals
535 HeapWord* const start = mr.start();
536 HeapWord* const end = mr.end();
538 // We used to use "block_start_careful" here. But we're actually happy
539 // to update the BOT while we do this...
540 HeapWord* cur = block_start(start);
541 assert(cur <= start, "Postcondition");
543 oop obj;
545 HeapWord* next = cur;
546 while (next <= start) {
547 cur = next;
548 obj = oop(cur);
549 if (obj->klass_or_null() == NULL) {
550 // Ran into an unparseable point.
551 return cur;
552 }
553 // Otherwise...
554 next = (cur + obj->size());
555 }
557 // If we finish the above loop...We have a parseable object that
558 // begins on or before the start of the memory region, and ends
559 // inside or spans the entire region.
561 assert(obj == oop(cur), "sanity");
562 assert(cur <= start &&
563 obj->klass_or_null() != NULL &&
564 (cur + obj->size()) > start,
565 "Loop postcondition");
567 if (!g1h->is_obj_dead(obj)) {
568 obj->oop_iterate(cl, mr);
569 }
571 while (cur < end) {
572 obj = oop(cur);
573 if (obj->klass_or_null() == NULL) {
574 // Ran into an unparseable point.
575 return cur;
576 };
578 // Otherwise:
579 next = (cur + obj->size());
581 if (!g1h->is_obj_dead(obj)) {
582 if (next < end || !obj->is_objArray()) {
583 // This object either does not span the MemRegion
584 // boundary, or if it does it's not an array.
585 // Apply closure to whole object.
586 obj->oop_iterate(cl);
587 } else {
588 // This obj is an array that spans the boundary.
589 // Stop at the boundary.
590 obj->oop_iterate(cl, mr);
591 }
592 }
593 cur = next;
594 }
595 return NULL;
596 }
598 // Code roots support
600 void HeapRegion::add_strong_code_root(nmethod* nm) {
601 HeapRegionRemSet* hrrs = rem_set();
602 hrrs->add_strong_code_root(nm);
603 }
605 void HeapRegion::remove_strong_code_root(nmethod* nm) {
606 HeapRegionRemSet* hrrs = rem_set();
607 hrrs->remove_strong_code_root(nm);
608 }
610 void HeapRegion::migrate_strong_code_roots() {
611 assert(in_collection_set(), "only collection set regions");
612 assert(!isHumongous(),
613 err_msg("humongous region "HR_FORMAT" should not have been added to collection set",
614 HR_FORMAT_PARAMS(this)));
616 HeapRegionRemSet* hrrs = rem_set();
617 hrrs->migrate_strong_code_roots();
618 }
620 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
621 HeapRegionRemSet* hrrs = rem_set();
622 hrrs->strong_code_roots_do(blk);
623 }
625 class VerifyStrongCodeRootOopClosure: public OopClosure {
626 const HeapRegion* _hr;
627 nmethod* _nm;
628 bool _failures;
629 bool _has_oops_in_region;
631 template <class T> void do_oop_work(T* p) {
632 T heap_oop = oopDesc::load_heap_oop(p);
633 if (!oopDesc::is_null(heap_oop)) {
634 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
636 // Note: not all the oops embedded in the nmethod are in the
637 // current region. We only look at those which are.
638 if (_hr->is_in(obj)) {
639 // Object is in the region. Check that its less than top
640 if (_hr->top() <= (HeapWord*)obj) {
641 // Object is above top
642 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
643 "["PTR_FORMAT", "PTR_FORMAT") is above "
644 "top "PTR_FORMAT,
645 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
646 _failures = true;
647 return;
648 }
649 // Nmethod has at least one oop in the current region
650 _has_oops_in_region = true;
651 }
652 }
653 }
655 public:
656 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
657 _hr(hr), _failures(false), _has_oops_in_region(false) {}
659 void do_oop(narrowOop* p) { do_oop_work(p); }
660 void do_oop(oop* p) { do_oop_work(p); }
662 bool failures() { return _failures; }
663 bool has_oops_in_region() { return _has_oops_in_region; }
664 };
666 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
667 const HeapRegion* _hr;
668 bool _failures;
669 public:
670 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
671 _hr(hr), _failures(false) {}
673 void do_code_blob(CodeBlob* cb) {
674 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
675 if (nm != NULL) {
676 // Verify that the nemthod is live
677 if (!nm->is_alive()) {
678 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
679 PTR_FORMAT" in its strong code roots",
680 _hr->bottom(), _hr->end(), nm);
681 _failures = true;
682 } else {
683 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
684 nm->oops_do(&oop_cl);
685 if (!oop_cl.has_oops_in_region()) {
686 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
687 PTR_FORMAT" in its strong code roots "
688 "with no pointers into region",
689 _hr->bottom(), _hr->end(), nm);
690 _failures = true;
691 } else if (oop_cl.failures()) {
692 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
693 "failures for nmethod "PTR_FORMAT,
694 _hr->bottom(), _hr->end(), nm);
695 _failures = true;
696 }
697 }
698 }
699 }
701 bool failures() { return _failures; }
702 };
704 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
705 if (!G1VerifyHeapRegionCodeRoots) {
706 // We're not verifying code roots.
707 return;
708 }
709 if (vo == VerifyOption_G1UseMarkWord) {
710 // Marking verification during a full GC is performed after class
711 // unloading, code cache unloading, etc so the strong code roots
712 // attached to each heap region are in an inconsistent state. They won't
713 // be consistent until the strong code roots are rebuilt after the
714 // actual GC. Skip verifying the strong code roots in this particular
715 // time.
716 assert(VerifyDuringGC, "only way to get here");
717 return;
718 }
720 HeapRegionRemSet* hrrs = rem_set();
721 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
723 // if this region is empty then there should be no entries
724 // on its strong code root list
725 if (is_empty()) {
726 if (strong_code_roots_length > 0) {
727 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
728 "but has "SIZE_FORMAT" code root entries",
729 bottom(), end(), strong_code_roots_length);
730 *failures = true;
731 }
732 return;
733 }
735 if (continuesHumongous()) {
736 if (strong_code_roots_length > 0) {
737 gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
738 "region but has "SIZE_FORMAT" code root entries",
739 HR_FORMAT_PARAMS(this), strong_code_roots_length);
740 *failures = true;
741 }
742 return;
743 }
745 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
746 strong_code_roots_do(&cb_cl);
748 if (cb_cl.failures()) {
749 *failures = true;
750 }
751 }
753 void HeapRegion::print() const { print_on(gclog_or_tty); }
754 void HeapRegion::print_on(outputStream* st) const {
755 if (isHumongous()) {
756 if (startsHumongous())
757 st->print(" HS");
758 else
759 st->print(" HC");
760 } else {
761 st->print(" ");
762 }
763 if (in_collection_set())
764 st->print(" CS");
765 else
766 st->print(" ");
767 if (is_young())
768 st->print(is_survivor() ? " SU" : " Y ");
769 else
770 st->print(" ");
771 if (is_empty())
772 st->print(" F");
773 else
774 st->print(" ");
775 st->print(" TS %5d", _gc_time_stamp);
776 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
777 prev_top_at_mark_start(), next_top_at_mark_start());
778 G1OffsetTableContigSpace::print_on(st);
779 }
781 class VerifyLiveClosure: public OopClosure {
782 private:
783 G1CollectedHeap* _g1h;
784 CardTableModRefBS* _bs;
785 oop _containing_obj;
786 bool _failures;
787 int _n_failures;
788 VerifyOption _vo;
789 public:
790 // _vo == UsePrevMarking -> use "prev" marking information,
791 // _vo == UseNextMarking -> use "next" marking information,
792 // _vo == UseMarkWord -> use mark word from object header.
793 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
794 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
795 _failures(false), _n_failures(0), _vo(vo)
796 {
797 BarrierSet* bs = _g1h->barrier_set();
798 if (bs->is_a(BarrierSet::CardTableModRef))
799 _bs = (CardTableModRefBS*)bs;
800 }
802 void set_containing_obj(oop obj) {
803 _containing_obj = obj;
804 }
806 bool failures() { return _failures; }
807 int n_failures() { return _n_failures; }
809 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
810 virtual void do_oop( oop* p) { do_oop_work(p); }
812 void print_object(outputStream* out, oop obj) {
813 #ifdef PRODUCT
814 Klass* k = obj->klass();
815 const char* class_name = InstanceKlass::cast(k)->external_name();
816 out->print_cr("class name %s", class_name);
817 #else // PRODUCT
818 obj->print_on(out);
819 #endif // PRODUCT
820 }
822 template <class T>
823 void do_oop_work(T* p) {
824 assert(_containing_obj != NULL, "Precondition");
825 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
826 "Precondition");
827 T heap_oop = oopDesc::load_heap_oop(p);
828 if (!oopDesc::is_null(heap_oop)) {
829 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
830 bool failed = false;
831 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
832 MutexLockerEx x(ParGCRareEvent_lock,
833 Mutex::_no_safepoint_check_flag);
835 if (!_failures) {
836 gclog_or_tty->cr();
837 gclog_or_tty->print_cr("----------");
838 }
839 if (!_g1h->is_in_closed_subset(obj)) {
840 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
841 gclog_or_tty->print_cr("Field "PTR_FORMAT
842 " of live obj "PTR_FORMAT" in region "
843 "["PTR_FORMAT", "PTR_FORMAT")",
844 p, (void*) _containing_obj,
845 from->bottom(), from->end());
846 print_object(gclog_or_tty, _containing_obj);
847 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
848 (void*) obj);
849 } else {
850 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
851 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
852 gclog_or_tty->print_cr("Field "PTR_FORMAT
853 " of live obj "PTR_FORMAT" in region "
854 "["PTR_FORMAT", "PTR_FORMAT")",
855 p, (void*) _containing_obj,
856 from->bottom(), from->end());
857 print_object(gclog_or_tty, _containing_obj);
858 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
859 "["PTR_FORMAT", "PTR_FORMAT")",
860 (void*) obj, to->bottom(), to->end());
861 print_object(gclog_or_tty, obj);
862 }
863 gclog_or_tty->print_cr("----------");
864 gclog_or_tty->flush();
865 _failures = true;
866 failed = true;
867 _n_failures++;
868 }
870 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
871 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
872 HeapRegion* to = _g1h->heap_region_containing(obj);
873 if (from != NULL && to != NULL &&
874 from != to &&
875 !to->isHumongous()) {
876 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
877 jbyte cv_field = *_bs->byte_for_const(p);
878 const jbyte dirty = CardTableModRefBS::dirty_card_val();
880 bool is_bad = !(from->is_young()
881 || to->rem_set()->contains_reference(p)
882 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
883 (_containing_obj->is_objArray() ?
884 cv_field == dirty
885 : cv_obj == dirty || cv_field == dirty));
886 if (is_bad) {
887 MutexLockerEx x(ParGCRareEvent_lock,
888 Mutex::_no_safepoint_check_flag);
890 if (!_failures) {
891 gclog_or_tty->cr();
892 gclog_or_tty->print_cr("----------");
893 }
894 gclog_or_tty->print_cr("Missing rem set entry:");
895 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
896 "of obj "PTR_FORMAT", "
897 "in region "HR_FORMAT,
898 p, (void*) _containing_obj,
899 HR_FORMAT_PARAMS(from));
900 _containing_obj->print_on(gclog_or_tty);
901 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
902 "in region "HR_FORMAT,
903 (void*) obj,
904 HR_FORMAT_PARAMS(to));
905 obj->print_on(gclog_or_tty);
906 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
907 cv_obj, cv_field);
908 gclog_or_tty->print_cr("----------");
909 gclog_or_tty->flush();
910 _failures = true;
911 if (!failed) _n_failures++;
912 }
913 }
914 }
915 }
916 }
917 };
919 // This really ought to be commoned up into OffsetTableContigSpace somehow.
920 // We would need a mechanism to make that code skip dead objects.
922 void HeapRegion::verify(VerifyOption vo,
923 bool* failures) const {
924 G1CollectedHeap* g1 = G1CollectedHeap::heap();
925 *failures = false;
926 HeapWord* p = bottom();
927 HeapWord* prev_p = NULL;
928 VerifyLiveClosure vl_cl(g1, vo);
929 bool is_humongous = isHumongous();
930 bool do_bot_verify = !is_young();
931 size_t object_num = 0;
932 while (p < top()) {
933 oop obj = oop(p);
934 size_t obj_size = obj->size();
935 object_num += 1;
937 if (is_humongous != g1->isHumongous(obj_size)) {
938 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
939 SIZE_FORMAT" words) in a %shumongous region",
940 p, g1->isHumongous(obj_size) ? "" : "non-",
941 obj_size, is_humongous ? "" : "non-");
942 *failures = true;
943 return;
944 }
946 // If it returns false, verify_for_object() will output the
947 // appropriate messasge.
948 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
949 *failures = true;
950 return;
951 }
953 if (!g1->is_obj_dead_cond(obj, this, vo)) {
954 if (obj->is_oop()) {
955 Klass* klass = obj->klass();
956 if (!klass->is_metaspace_object()) {
957 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
958 "not metadata", klass, (void *)obj);
959 *failures = true;
960 return;
961 } else if (!klass->is_klass()) {
962 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
963 "not a klass", klass, (void *)obj);
964 *failures = true;
965 return;
966 } else {
967 vl_cl.set_containing_obj(obj);
968 obj->oop_iterate_no_header(&vl_cl);
969 if (vl_cl.failures()) {
970 *failures = true;
971 }
972 if (G1MaxVerifyFailures >= 0 &&
973 vl_cl.n_failures() >= G1MaxVerifyFailures) {
974 return;
975 }
976 }
977 } else {
978 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
979 *failures = true;
980 return;
981 }
982 }
983 prev_p = p;
984 p += obj_size;
985 }
987 if (p != top()) {
988 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
989 "does not match top "PTR_FORMAT, p, top());
990 *failures = true;
991 return;
992 }
994 HeapWord* the_end = end();
995 assert(p == top(), "it should still hold");
996 // Do some extra BOT consistency checking for addresses in the
997 // range [top, end). BOT look-ups in this range should yield
998 // top. No point in doing that if top == end (there's nothing there).
999 if (p < the_end) {
1000 // Look up top
1001 HeapWord* addr_1 = p;
1002 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
1003 if (b_start_1 != p) {
1004 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
1005 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
1006 addr_1, b_start_1, p);
1007 *failures = true;
1008 return;
1009 }
1011 // Look up top + 1
1012 HeapWord* addr_2 = p + 1;
1013 if (addr_2 < the_end) {
1014 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
1015 if (b_start_2 != p) {
1016 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
1017 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
1018 addr_2, b_start_2, p);
1019 *failures = true;
1020 return;
1021 }
1022 }
1024 // Look up an address between top and end
1025 size_t diff = pointer_delta(the_end, p) / 2;
1026 HeapWord* addr_3 = p + diff;
1027 if (addr_3 < the_end) {
1028 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
1029 if (b_start_3 != p) {
1030 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
1031 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
1032 addr_3, b_start_3, p);
1033 *failures = true;
1034 return;
1035 }
1036 }
1038 // Loook up end - 1
1039 HeapWord* addr_4 = the_end - 1;
1040 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
1041 if (b_start_4 != p) {
1042 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
1043 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
1044 addr_4, b_start_4, p);
1045 *failures = true;
1046 return;
1047 }
1048 }
1050 if (is_humongous && object_num > 1) {
1051 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
1052 "but has "SIZE_FORMAT", objects",
1053 bottom(), end(), object_num);
1054 *failures = true;
1055 return;
1056 }
1058 verify_strong_code_roots(vo, failures);
1059 }
1061 void HeapRegion::verify() const {
1062 bool dummy = false;
1063 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
1064 }
1066 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
1067 // away eventually.
1069 void G1OffsetTableContigSpace::clear(bool mangle_space) {
1070 ContiguousSpace::clear(mangle_space);
1071 _offsets.zero_bottom_entry();
1072 _offsets.initialize_threshold();
1073 }
1075 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
1076 Space::set_bottom(new_bottom);
1077 _offsets.set_bottom(new_bottom);
1078 }
1080 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
1081 Space::set_end(new_end);
1082 _offsets.resize(new_end - bottom());
1083 }
1085 void G1OffsetTableContigSpace::print() const {
1086 print_short();
1087 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1088 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1089 bottom(), top(), _offsets.threshold(), end());
1090 }
1092 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
1093 return _offsets.initialize_threshold();
1094 }
1096 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
1097 HeapWord* end) {
1098 _offsets.alloc_block(start, end);
1099 return _offsets.threshold();
1100 }
1102 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
1103 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1104 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
1105 if (_gc_time_stamp < g1h->get_gc_time_stamp())
1106 return top();
1107 else
1108 return ContiguousSpace::saved_mark_word();
1109 }
1111 void G1OffsetTableContigSpace::set_saved_mark() {
1112 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1113 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
1115 if (_gc_time_stamp < curr_gc_time_stamp) {
1116 // The order of these is important, as another thread might be
1117 // about to start scanning this region. If it does so after
1118 // set_saved_mark and before _gc_time_stamp = ..., then the latter
1119 // will be false, and it will pick up top() as the high water mark
1120 // of region. If it does so after _gc_time_stamp = ..., then it
1121 // will pick up the right saved_mark_word() as the high water mark
1122 // of the region. Either way, the behaviour will be correct.
1123 ContiguousSpace::set_saved_mark();
1124 OrderAccess::storestore();
1125 _gc_time_stamp = curr_gc_time_stamp;
1126 // No need to do another barrier to flush the writes above. If
1127 // this is called in parallel with other threads trying to
1128 // allocate into the region, the caller should call this while
1129 // holding a lock and when the lock is released the writes will be
1130 // flushed.
1131 }
1132 }
1134 G1OffsetTableContigSpace::
1135 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1136 MemRegion mr) :
1137 _offsets(sharedOffsetArray, mr),
1138 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1139 _gc_time_stamp(0)
1140 {
1141 _offsets.set_space(this);
1142 // false ==> we'll do the clearing if there's clearing to be done.
1143 ContiguousSpace::initialize(mr, false, SpaceDecorator::Mangle);
1144 _offsets.zero_bottom_entry();
1145 _offsets.initialize_threshold();
1146 }
