1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1OopClosures.inline.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionBounds.inline.hpp"
32 #include "gc/g1/heapRegionManager.inline.hpp"
33 #include "gc/g1/heapRegionRemSet.hpp"
34 #include "gc/shared/genOopClosures.inline.hpp"
35 #include "gc/shared/liveRange.hpp"
36 #include "gc/shared/space.inline.hpp"
37 #include "memory/iterator.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41
42 int HeapRegion::LogOfHRGrainBytes = 0;
43 int HeapRegion::LogOfHRGrainWords = 0;
44 size_t HeapRegion::GrainBytes = 0;
45 size_t HeapRegion::GrainWords = 0;
46 size_t HeapRegion::CardsPerRegion = 0;
47
48 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
49 HeapRegion* hr,
50 G1ParPushHeapRSClosure* cl,
51 CardTableModRefBS::PrecisionStyle precision) :
52 DirtyCardToOopClosure(hr, cl, precision, NULL),
53 _hr(hr), _rs_scan(cl), _g1(g1) { }
54
55 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
56 OopClosure* oc) :
57 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
58
59 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
60 HeapWord* bottom,
61 HeapWord* top) {
62 G1CollectedHeap* g1h = _g1;
63 size_t oop_size;
64 HeapWord* cur = bottom;
65
66 // Start filtering what we add to the remembered set. If the object is
67 // not considered dead, either because it is marked (in the mark bitmap)
68 // or it was allocated after marking finished, then we add it. Otherwise
69 // we can safely ignore the object.
70 if (!g1h->is_obj_dead(oop(cur), _hr)) {
71 oop_size = oop(cur)->oop_iterate(_rs_scan, mr);
72 } else {
73 oop_size = _hr->block_size(cur);
74 }
75
76 cur += oop_size;
77
78 if (cur < top) {
79 oop cur_oop = oop(cur);
80 oop_size = _hr->block_size(cur);
81 HeapWord* next_obj = cur + oop_size;
82 while (next_obj < top) {
83 // Keep filtering the remembered set.
84 if (!g1h->is_obj_dead(cur_oop, _hr)) {
85 // Bottom lies entirely below top, so we can call the
86 // non-memRegion version of oop_iterate below.
87 cur_oop->oop_iterate(_rs_scan);
88 }
89 cur = next_obj;
90 cur_oop = oop(cur);
91 oop_size = _hr->block_size(cur);
92 next_obj = cur + oop_size;
93 }
94
95 // Last object. Need to do dead-obj filtering here too.
96 if (!g1h->is_obj_dead(oop(cur), _hr)) {
97 oop(cur)->oop_iterate(_rs_scan, mr);
98 }
99 }
100 }
101
102 size_t HeapRegion::max_region_size() {
103 return HeapRegionBounds::max_size();
104 }
105
106 size_t HeapRegion::min_region_size_in_words() {
107 return HeapRegionBounds::min_size() >> LogHeapWordSize;
108 }
109
110 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
111 size_t region_size = G1HeapRegionSize;
112 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
113 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
114 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
115 HeapRegionBounds::min_size());
116 }
117
118 int region_size_log = log2_long((jlong) region_size);
119 // Recalculate the region size to make sure it's a power of
120 // 2. This means that region_size is the largest power of 2 that's
121 // <= what we've calculated so far.
122 region_size = ((size_t)1 << region_size_log);
123
124 // Now make sure that we don't go over or under our limits.
125 if (region_size < HeapRegionBounds::min_size()) {
126 region_size = HeapRegionBounds::min_size();
127 } else if (region_size > HeapRegionBounds::max_size()) {
128 region_size = HeapRegionBounds::max_size();
129 }
130
131 // And recalculate the log.
132 region_size_log = log2_long((jlong) region_size);
133
134 // Now, set up the globals.
135 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
136 LogOfHRGrainBytes = region_size_log;
137
138 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
139 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
140
141 guarantee(GrainBytes == 0, "we should only set it once");
142 // The cast to int is safe, given that we've bounded region_size by
143 // MIN_REGION_SIZE and MAX_REGION_SIZE.
144 GrainBytes = region_size;
145
146 guarantee(GrainWords == 0, "we should only set it once");
147 GrainWords = GrainBytes >> LogHeapWordSize;
148 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
149
150 guarantee(CardsPerRegion == 0, "we should only set it once");
151 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
152 }
153
154 void HeapRegion::reset_after_compaction() {
155 G1OffsetTableContigSpace::reset_after_compaction();
156 // After a compaction the mark bitmap is invalid, so we must
157 // treat all objects as being inside the unmarked area.
158 zero_marked_bytes();
159 init_top_at_mark_start();
160 }
161
162 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
163 assert(_humongous_start_region == NULL,
164 "we should have already filtered out humongous regions");
165 assert(_end == orig_end(),
166 "we should have already filtered out humongous regions");
167 assert(!in_collection_set(),
168 err_msg("Should not clear heap region %u in the collection set", hrm_index()));
169
170 set_allocation_context(AllocationContext::system());
171 set_young_index_in_cset(-1);
172 uninstall_surv_rate_group();
173 set_free();
174 reset_pre_dummy_top();
175
176 if (!par) {
177 // If this is parallel, this will be done later.
178 HeapRegionRemSet* hrrs = rem_set();
179 if (locked) {
180 hrrs->clear_locked();
181 } else {
182 hrrs->clear();
183 }
184 }
185 zero_marked_bytes();
186
187 _offsets.resize(HeapRegion::GrainWords);
188 init_top_at_mark_start();
189 if (clear_space) clear(SpaceDecorator::Mangle);
190 }
191
192 void HeapRegion::par_clear() {
193 assert(used() == 0, "the region should have been already cleared");
194 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
195 HeapRegionRemSet* hrrs = rem_set();
196 hrrs->clear();
197 CardTableModRefBS* ct_bs =
198 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
199 ct_bs->clear(MemRegion(bottom(), end()));
200 }
201
202 void HeapRegion::calc_gc_efficiency() {
203 // GC efficiency is the ratio of how much space would be
204 // reclaimed over how long we predict it would take to reclaim it.
205 G1CollectedHeap* g1h = G1CollectedHeap::heap();
206 G1CollectorPolicy* g1p = g1h->g1_policy();
207
208 // Retrieve a prediction of the elapsed time for this region for
209 // a mixed gc because the region will only be evacuated during a
210 // mixed gc.
211 double region_elapsed_time_ms =
212 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
213 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
214 }
215
216 void HeapRegion::set_starts_humongous(HeapWord* new_top, HeapWord* new_end) {
217 assert(!is_humongous(), "sanity / pre-condition");
218 assert(end() == orig_end(),
219 "Should be normal before the humongous object allocation");
220 assert(top() == bottom(), "should be empty");
221 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
222
223 _type.set_starts_humongous();
224 _humongous_start_region = this;
225
226 set_end(new_end);
227 _offsets.set_for_starts_humongous(new_top);
228 }
229
230 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
231 assert(!is_humongous(), "sanity / pre-condition");
232 assert(end() == orig_end(),
233 "Should be normal before the humongous object allocation");
234 assert(top() == bottom(), "should be empty");
235 assert(first_hr->is_starts_humongous(), "pre-condition");
236
237 _type.set_continues_humongous();
238 _humongous_start_region = first_hr;
239 }
240
241 void HeapRegion::clear_humongous() {
242 assert(is_humongous(), "pre-condition");
243
244 if (is_starts_humongous()) {
245 assert(top() <= end(), "pre-condition");
246 set_end(orig_end());
247 if (top() > end()) {
248 // at least one "continues humongous" region after it
249 set_top(end());
250 }
251 } else {
252 // continues humongous
253 assert(end() == orig_end(), "sanity");
254 }
255
256 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
257 _humongous_start_region = NULL;
258 }
259
260 HeapRegion::HeapRegion(uint hrm_index,
261 G1BlockOffsetSharedArray* sharedOffsetArray,
262 MemRegion mr) :
263 G1OffsetTableContigSpace(sharedOffsetArray, mr),
264 _hrm_index(hrm_index),
265 _allocation_context(AllocationContext::system()),
266 _humongous_start_region(NULL),
267 _next_in_special_set(NULL),
268 _evacuation_failed(false),
269 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
270 _next_young_region(NULL),
271 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
272 #ifdef ASSERT
273 _containing_set(NULL),
274 #endif // ASSERT
275 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
276 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
277 _predicted_bytes_to_copy(0)
278 {
279 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
280 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
281
282 initialize(mr);
283 }
284
285 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
286 assert(_rem_set->is_empty(), "Remembered set must be empty");
287
288 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
289
290 hr_clear(false /*par*/, false /*clear_space*/);
291 set_top(bottom());
292 record_timestamp();
293
294 assert(mr.end() == orig_end(),
295 err_msg("Given region end address " PTR_FORMAT " should match exactly "
296 "bottom plus one region size, i.e. " PTR_FORMAT,
297 p2i(mr.end()), p2i(orig_end())));
298 }
299
300 CompactibleSpace* HeapRegion::next_compaction_space() const {
301 return G1CollectedHeap::heap()->next_compaction_region(this);
302 }
303
304 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
305 bool during_conc_mark) {
306 // We always recreate the prev marking info and we'll explicitly
307 // mark all objects we find to be self-forwarded on the prev
308 // bitmap. So all objects need to be below PTAMS.
309 _prev_marked_bytes = 0;
310
311 if (during_initial_mark) {
312 // During initial-mark, we'll also explicitly mark all objects
313 // we find to be self-forwarded on the next bitmap. So all
314 // objects need to be below NTAMS.
315 _next_top_at_mark_start = top();
316 _next_marked_bytes = 0;
317 } else if (during_conc_mark) {
318 // During concurrent mark, all objects in the CSet (including
319 // the ones we find to be self-forwarded) are implicitly live.
320 // So all objects need to be above NTAMS.
321 _next_top_at_mark_start = bottom();
322 _next_marked_bytes = 0;
323 }
324 }
325
326 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
327 bool during_conc_mark,
328 size_t marked_bytes) {
329 assert(marked_bytes <= used(),
330 err_msg("marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used()));
331 _prev_top_at_mark_start = top();
332 _prev_marked_bytes = marked_bytes;
333 }
334
335 HeapWord*
336 HeapRegion::object_iterate_mem_careful(MemRegion mr,
337 ObjectClosure* cl) {
338 G1CollectedHeap* g1h = G1CollectedHeap::heap();
339 // We used to use "block_start_careful" here. But we're actually happy
340 // to update the BOT while we do this...
341 HeapWord* cur = block_start(mr.start());
342 mr = mr.intersection(used_region());
343 if (mr.is_empty()) return NULL;
344 // Otherwise, find the obj that extends onto mr.start().
345
346 assert(cur <= mr.start()
347 && (oop(cur)->klass_or_null() == NULL ||
348 cur + oop(cur)->size() > mr.start()),
349 "postcondition of block_start");
350 oop obj;
351 while (cur < mr.end()) {
352 obj = oop(cur);
353 if (obj->klass_or_null() == NULL) {
354 // Ran into an unparseable point.
355 return cur;
356 } else if (!g1h->is_obj_dead(obj)) {
357 cl->do_object(obj);
358 }
359 cur += block_size(cur);
360 }
361 return NULL;
362 }
363
364
365 bool HeapRegion::clean_card(MemRegion& mr,
366 bool filter_young,
367 jbyte* &card_ptr) {
368 // Currently, we should only have to clean the card if filter_young
369 // is true and vice versa.
370 if (filter_young) {
371 assert(card_ptr != NULL, "pre-condition");
372 } else {
373 assert(card_ptr == NULL, "pre-condition");
374 }
375 G1CollectedHeap* g1h = G1CollectedHeap::heap();
376
377 // If we're within a stop-world GC, then we might look at a card in a
378 // GC alloc region that extends onto a GC LAB, which may not be
379 // parseable. Stop such at the "scan_top" of the region.
380 if (g1h->is_gc_active()) {
381 mr = mr.intersection(MemRegion(bottom(), scan_top()));
382 } else {
383 mr = mr.intersection(used_region());
384 }
385 if (mr.is_empty()) return false;
386 // Otherwise, find the obj that extends onto mr.start().
387
388 // The intersection of the incoming mr (for the card) and the
389 // allocated part of the region is non-empty. This implies that
390 // we have actually allocated into this region. The code in
391 // G1CollectedHeap.cpp that allocates a new region sets the
392 // is_young tag on the region before allocating. Thus we
393 // safely know if this region is young.
394 if (is_young() && filter_young) {
395 return false;
396 }
397
398 assert(!is_young(), "check value of filter_young");
399
400 // We can only clean the card here, after we make the decision that
401 // the card is not young. And we only clean the card if we have been
402 // asked to (i.e., card_ptr != NULL).
403 if (card_ptr != NULL) {
404 *card_ptr = CardTableModRefBS::clean_card_val();
405 }
406
407 return true;
408 }
409
410 HeapWord* HeapRegion::process_oops_on_card(MemRegion mr,
411 FilterOutOfRegionClosure *cl,
412 jbyte *card_ptr) {
413 G1CollectedHeap* g1h = G1CollectedHeap::heap();
414 G1SATBCardTableLoggingModRefBS* bs = g1h->g1_barrier_set();
415 // Cache the boundaries of the memory region in some const locals
416 HeapWord* const start = mr.start();
417 HeapWord* const end = mr.end();
418
419 HeapWord* cur;
420
421 // We used to use "block_start_careful" here. But we're actually happy
422 // to update the BOT while we do this...
423 cur = block_start(start);
424 assert(cur <= start, "Postcondition");
425
426 oop obj;
427
428 HeapWord* next = cur;
429 do {
430 cur = next;
431 obj = oop(cur);
432 if (obj->klass_or_null() == NULL) {
433 // Ran into an unparseable point.
434 return cur;
435 }
436 // Otherwise...
437 next = cur + block_size(cur);
438 } while (next <= start);
439
440 // If we finish the above loop...We have a parseable object that
441 // begins on or before the start of the memory region, and ends
442 // inside or spans the entire region.
443 assert(cur <= start, "Loop postcondition");
444 assert(obj->klass_or_null() != NULL, "Loop postcondition");
445
446 do {
447 obj = oop(cur);
448 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
449 if (obj->klass_or_null() == NULL) {
450 // Ran into an unparseable point.
451 return cur;
452 }
453
454 // Advance the current pointer. "obj" still points to the object to iterate.
455 cur = cur + block_size(cur);
456
457 if (!g1h->is_obj_dead(obj)) {
458 // Non-objArrays are sometimes marked imprecise at the object start. We
459 // always need to iterate over them in full.
460 // We only iterate over object arrays in full if they are completely contained
461 // in the memory region.
462 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
463 obj->oop_iterate(cl);
464 } else {
465 obj->oop_iterate(cl, mr);
466 }
467 }
468 } while (cur < end);
469
470 return NULL;
471 }
472
473 HeapWord*
474 HeapRegion::
475 oops_on_card_seq_iterate_careful(MemRegion mr,
476 FilterOutOfRegionClosure* cl,
477 bool filter_young,
478 jbyte* card_ptr) {
479 if (!clean_card(mr, filter_young, card_ptr)) return NULL;
480 if (card_ptr != NULL) OrderAccess::storeload(); // serialize card cleaning
481 return process_oops_on_card(mr, cl, card_ptr);
482 }
483
484 // Code roots support
485
486 void HeapRegion::add_strong_code_root(nmethod* nm) {
487 HeapRegionRemSet* hrrs = rem_set();
488 hrrs->add_strong_code_root(nm);
489 }
490
491 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
492 assert_locked_or_safepoint(CodeCache_lock);
493 HeapRegionRemSet* hrrs = rem_set();
494 hrrs->add_strong_code_root_locked(nm);
495 }
496
497 void HeapRegion::remove_strong_code_root(nmethod* nm) {
498 HeapRegionRemSet* hrrs = rem_set();
499 hrrs->remove_strong_code_root(nm);
500 }
501
502 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
503 HeapRegionRemSet* hrrs = rem_set();
504 hrrs->strong_code_roots_do(blk);
505 }
506
507 class VerifyStrongCodeRootOopClosure: public OopClosure {
508 const HeapRegion* _hr;
509 nmethod* _nm;
510 bool _failures;
511 bool _has_oops_in_region;
512
513 template <class T> void do_oop_work(T* p) {
514 T heap_oop = oopDesc::load_heap_oop(p);
515 if (!oopDesc::is_null(heap_oop)) {
516 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
517
518 // Note: not all the oops embedded in the nmethod are in the
519 // current region. We only look at those which are.
520 if (_hr->is_in(obj)) {
521 // Object is in the region. Check that its less than top
522 if (_hr->top() <= (HeapWord*)obj) {
523 // Object is above top
524 gclog_or_tty->print_cr("Object " PTR_FORMAT " in region "
525 "[" PTR_FORMAT ", " PTR_FORMAT ") is above "
526 "top " PTR_FORMAT,
527 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
528 _failures = true;
529 return;
530 }
531 // Nmethod has at least one oop in the current region
532 _has_oops_in_region = true;
533 }
534 }
535 }
536
537 public:
538 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
539 _hr(hr), _failures(false), _has_oops_in_region(false) {}
540
541 void do_oop(narrowOop* p) { do_oop_work(p); }
542 void do_oop(oop* p) { do_oop_work(p); }
543
544 bool failures() { return _failures; }
545 bool has_oops_in_region() { return _has_oops_in_region; }
546 };
547
548 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
549 const HeapRegion* _hr;
550 bool _failures;
551 public:
552 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
553 _hr(hr), _failures(false) {}
554
555 void do_code_blob(CodeBlob* cb) {
556 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
557 if (nm != NULL) {
558 // Verify that the nemthod is live
559 if (!nm->is_alive()) {
560 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod "
561 PTR_FORMAT " in its strong code roots",
562 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
563 _failures = true;
564 } else {
565 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
566 nm->oops_do(&oop_cl);
567 if (!oop_cl.has_oops_in_region()) {
568 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod "
569 PTR_FORMAT " in its strong code roots "
570 "with no pointers into region",
571 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
572 _failures = true;
573 } else if (oop_cl.failures()) {
574 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has other "
575 "failures for nmethod " PTR_FORMAT,
576 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
577 _failures = true;
578 }
579 }
580 }
581 }
582
583 bool failures() { return _failures; }
584 };
585
586 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
587 if (!G1VerifyHeapRegionCodeRoots) {
588 // We're not verifying code roots.
589 return;
590 }
591 if (vo == VerifyOption_G1UseMarkWord) {
592 // Marking verification during a full GC is performed after class
593 // unloading, code cache unloading, etc so the strong code roots
594 // attached to each heap region are in an inconsistent state. They won't
595 // be consistent until the strong code roots are rebuilt after the
596 // actual GC. Skip verifying the strong code roots in this particular
597 // time.
598 assert(VerifyDuringGC, "only way to get here");
599 return;
600 }
601
602 HeapRegionRemSet* hrrs = rem_set();
603 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
604
605 // if this region is empty then there should be no entries
606 // on its strong code root list
607 if (is_empty()) {
608 if (strong_code_roots_length > 0) {
609 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is empty "
610 "but has " SIZE_FORMAT " code root entries",
611 p2i(bottom()), p2i(end()), strong_code_roots_length);
612 *failures = true;
613 }
614 return;
615 }
616
617 if (is_continues_humongous()) {
618 if (strong_code_roots_length > 0) {
619 gclog_or_tty->print_cr("region " HR_FORMAT " is a continuation of a humongous "
620 "region but has " SIZE_FORMAT " code root entries",
621 HR_FORMAT_PARAMS(this), strong_code_roots_length);
622 *failures = true;
623 }
624 return;
625 }
626
627 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
628 strong_code_roots_do(&cb_cl);
629
630 if (cb_cl.failures()) {
631 *failures = true;
632 }
633 }
634
635 void HeapRegion::print() const { print_on(gclog_or_tty); }
636 void HeapRegion::print_on(outputStream* st) const {
637 st->print("AC%4u", allocation_context());
638
639 st->print(" %2s", get_short_type_str());
640 if (in_collection_set())
641 st->print(" CS");
642 else
643 st->print(" ");
644 st->print(" TS %5d", _gc_time_stamp);
645 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT,
646 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
647 G1OffsetTableContigSpace::print_on(st);
648 }
649
650 class VerifyLiveClosure: public OopClosure {
651 private:
652 G1CollectedHeap* _g1h;
653 CardTableModRefBS* _bs;
654 oop _containing_obj;
655 bool _failures;
656 int _n_failures;
657 VerifyOption _vo;
658 public:
659 // _vo == UsePrevMarking -> use "prev" marking information,
660 // _vo == UseNextMarking -> use "next" marking information,
661 // _vo == UseMarkWord -> use mark word from object header.
662 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
663 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
664 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo)
665 { }
666
667 void set_containing_obj(oop obj) {
668 _containing_obj = obj;
669 }
670
671 bool failures() { return _failures; }
672 int n_failures() { return _n_failures; }
673
674 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
675 virtual void do_oop( oop* p) { do_oop_work(p); }
676
677 void print_object(outputStream* out, oop obj) {
678 #ifdef PRODUCT
679 Klass* k = obj->klass();
680 const char* class_name = InstanceKlass::cast(k)->external_name();
681 out->print_cr("class name %s", class_name);
682 #else // PRODUCT
683 obj->print_on(out);
684 #endif // PRODUCT
685 }
686
687 template <class T>
688 void do_oop_work(T* p) {
689 assert(_containing_obj != NULL, "Precondition");
690 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
691 "Precondition");
692 T heap_oop = oopDesc::load_heap_oop(p);
693 if (!oopDesc::is_null(heap_oop)) {
694 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
695 bool failed = false;
696 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
697 MutexLockerEx x(ParGCRareEvent_lock,
698 Mutex::_no_safepoint_check_flag);
699
700 if (!_failures) {
701 gclog_or_tty->cr();
702 gclog_or_tty->print_cr("----------");
703 }
704 if (!_g1h->is_in_closed_subset(obj)) {
705 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
706 gclog_or_tty->print_cr("Field " PTR_FORMAT
707 " of live obj " PTR_FORMAT " in region "
708 "[" PTR_FORMAT ", " PTR_FORMAT ")",
709 p2i(p), p2i(_containing_obj),
710 p2i(from->bottom()), p2i(from->end()));
711 print_object(gclog_or_tty, _containing_obj);
712 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " not in the heap",
713 p2i(obj));
714 } else {
715 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
716 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
717 gclog_or_tty->print_cr("Field " PTR_FORMAT
718 " of live obj " PTR_FORMAT " in region "
719 "[" PTR_FORMAT ", " PTR_FORMAT ")",
720 p2i(p), p2i(_containing_obj),
721 p2i(from->bottom()), p2i(from->end()));
722 print_object(gclog_or_tty, _containing_obj);
723 gclog_or_tty->print_cr("points to dead obj " PTR_FORMAT " in region "
724 "[" PTR_FORMAT ", " PTR_FORMAT ")",
725 p2i(obj), p2i(to->bottom()), p2i(to->end()));
726 print_object(gclog_or_tty, obj);
727 }
728 gclog_or_tty->print_cr("----------");
729 gclog_or_tty->flush();
730 _failures = true;
731 failed = true;
732 _n_failures++;
733 }
734
735 if (!_g1h->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
736 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
737 HeapRegion* to = _g1h->heap_region_containing(obj);
738 if (from != NULL && to != NULL &&
739 from != to &&
740 !to->is_pinned()) {
741 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
742 jbyte cv_field = *_bs->byte_for_const(p);
743 const jbyte dirty = CardTableModRefBS::dirty_card_val();
744
745 bool is_bad = !(from->is_young()
746 || to->rem_set()->contains_reference(p)
747 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
748 (_containing_obj->is_objArray() ?
749 cv_field == dirty
750 : cv_obj == dirty || cv_field == dirty));
751 if (is_bad) {
752 MutexLockerEx x(ParGCRareEvent_lock,
753 Mutex::_no_safepoint_check_flag);
754
755 if (!_failures) {
756 gclog_or_tty->cr();
757 gclog_or_tty->print_cr("----------");
758 }
759 gclog_or_tty->print_cr("Missing rem set entry:");
760 gclog_or_tty->print_cr("Field " PTR_FORMAT " "
761 "of obj " PTR_FORMAT ", "
762 "in region " HR_FORMAT,
763 p2i(p), p2i(_containing_obj),
764 HR_FORMAT_PARAMS(from));
765 _containing_obj->print_on(gclog_or_tty);
766 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " "
767 "in region " HR_FORMAT,
768 p2i(obj),
769 HR_FORMAT_PARAMS(to));
770 obj->print_on(gclog_or_tty);
771 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
772 cv_obj, cv_field);
773 gclog_or_tty->print_cr("----------");
774 gclog_or_tty->flush();
775 _failures = true;
776 if (!failed) _n_failures++;
777 }
778 }
779 }
780 }
781 }
782 };
783
784 // This really ought to be commoned up into OffsetTableContigSpace somehow.
785 // We would need a mechanism to make that code skip dead objects.
786
787 void HeapRegion::verify(VerifyOption vo,
788 bool* failures) const {
789 G1CollectedHeap* g1 = G1CollectedHeap::heap();
790 *failures = false;
791 HeapWord* p = bottom();
792 HeapWord* prev_p = NULL;
793 VerifyLiveClosure vl_cl(g1, vo);
794 bool is_region_humongous = is_humongous();
795 size_t object_num = 0;
796 while (p < top()) {
797 oop obj = oop(p);
798 size_t obj_size = block_size(p);
799 object_num += 1;
800
801 if (is_region_humongous != g1->is_humongous(obj_size) &&
802 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
803 gclog_or_tty->print_cr("obj " PTR_FORMAT " is of %shumongous size ("
804 SIZE_FORMAT " words) in a %shumongous region",
805 p2i(p), g1->is_humongous(obj_size) ? "" : "non-",
806 obj_size, is_region_humongous ? "" : "non-");
807 *failures = true;
808 return;
809 }
810
811 if (!g1->is_obj_dead_cond(obj, this, vo)) {
812 if (obj->is_oop()) {
813 Klass* klass = obj->klass();
814 bool is_metaspace_object = Metaspace::contains(klass) ||
815 (vo == VerifyOption_G1UsePrevMarking &&
816 ClassLoaderDataGraph::unload_list_contains(klass));
817 if (!is_metaspace_object) {
818 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
819 "not metadata", p2i(klass), p2i(obj));
820 *failures = true;
821 return;
822 } else if (!klass->is_klass()) {
823 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
824 "not a klass", p2i(klass), p2i(obj));
825 *failures = true;
826 return;
827 } else {
828 vl_cl.set_containing_obj(obj);
829 obj->oop_iterate_no_header(&vl_cl);
830 if (vl_cl.failures()) {
831 *failures = true;
832 }
833 if (G1MaxVerifyFailures >= 0 &&
834 vl_cl.n_failures() >= G1MaxVerifyFailures) {
835 return;
836 }
837 }
838 } else {
839 gclog_or_tty->print_cr(PTR_FORMAT " no an oop", p2i(obj));
840 *failures = true;
841 return;
842 }
843 }
844 prev_p = p;
845 p += obj_size;
846 }
847
848 if (!is_young() && !is_empty()) {
849 _offsets.verify();
850 }
851
852 if (p != top()) {
853 gclog_or_tty->print_cr("end of last object " PTR_FORMAT " "
854 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
855 *failures = true;
856 return;
857 }
858
859 HeapWord* the_end = end();
860 assert(p == top(), "it should still hold");
861 // Do some extra BOT consistency checking for addresses in the
862 // range [top, end). BOT look-ups in this range should yield
863 // top. No point in doing that if top == end (there's nothing there).
864 if (p < the_end) {
865 // Look up top
866 HeapWord* addr_1 = p;
867 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
868 if (b_start_1 != p) {
869 gclog_or_tty->print_cr("BOT look up for top: " PTR_FORMAT " "
870 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
871 p2i(addr_1), p2i(b_start_1), p2i(p));
872 *failures = true;
873 return;
874 }
875
876 // Look up top + 1
877 HeapWord* addr_2 = p + 1;
878 if (addr_2 < the_end) {
879 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
880 if (b_start_2 != p) {
881 gclog_or_tty->print_cr("BOT look up for top + 1: " PTR_FORMAT " "
882 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
883 p2i(addr_2), p2i(b_start_2), p2i(p));
884 *failures = true;
885 return;
886 }
887 }
888
889 // Look up an address between top and end
890 size_t diff = pointer_delta(the_end, p) / 2;
891 HeapWord* addr_3 = p + diff;
892 if (addr_3 < the_end) {
893 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
894 if (b_start_3 != p) {
895 gclog_or_tty->print_cr("BOT look up for top + diff: " PTR_FORMAT " "
896 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
897 p2i(addr_3), p2i(b_start_3), p2i(p));
898 *failures = true;
899 return;
900 }
901 }
902
903 // Look up end - 1
904 HeapWord* addr_4 = the_end - 1;
905 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
906 if (b_start_4 != p) {
907 gclog_or_tty->print_cr("BOT look up for end - 1: " PTR_FORMAT " "
908 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
909 p2i(addr_4), p2i(b_start_4), p2i(p));
910 *failures = true;
911 return;
912 }
913 }
914
915 if (is_region_humongous && object_num > 1) {
916 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is humongous "
917 "but has " SIZE_FORMAT ", objects",
918 p2i(bottom()), p2i(end()), object_num);
919 *failures = true;
920 return;
921 }
922
923 verify_strong_code_roots(vo, failures);
924 }
925
926 void HeapRegion::verify() const {
927 bool dummy = false;
928 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
929 }
930
931 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
932 scan_and_forward(this, cp);
933 }
934
935 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
936 // away eventually.
937
938 void G1OffsetTableContigSpace::clear(bool mangle_space) {
939 set_top(bottom());
940 _scan_top = bottom();
941 CompactibleSpace::clear(mangle_space);
942 reset_bot();
943 }
944
945 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
946 Space::set_bottom(new_bottom);
947 _offsets.set_bottom(new_bottom);
948 }
949
950 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
951 Space::set_end(new_end);
952 _offsets.resize(new_end - bottom());
953 }
954
955 #ifndef PRODUCT
956 void G1OffsetTableContigSpace::mangle_unused_area() {
957 mangle_unused_area_complete();
958 }
959
960 void G1OffsetTableContigSpace::mangle_unused_area_complete() {
961 SpaceMangler::mangle_region(MemRegion(top(), end()));
962 }
963 #endif
964
965 void G1OffsetTableContigSpace::print() const {
966 print_short();
967 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
968 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
969 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
970 }
971
972 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
973 return _offsets.initialize_threshold();
974 }
975
976 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
977 HeapWord* end) {
978 _offsets.alloc_block(start, end);
979 return _offsets.threshold();
980 }
981
982 HeapWord* G1OffsetTableContigSpace::scan_top() const {
983 G1CollectedHeap* g1h = G1CollectedHeap::heap();
984 HeapWord* local_top = top();
985 OrderAccess::loadload();
986 const unsigned local_time_stamp = _gc_time_stamp;
987 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
988 if (local_time_stamp < g1h->get_gc_time_stamp()) {
989 return local_top;
990 } else {
991 return _scan_top;
992 }
993 }
994
995 void G1OffsetTableContigSpace::record_timestamp() {
996 G1CollectedHeap* g1h = G1CollectedHeap::heap();
997 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
998
999 if (_gc_time_stamp < curr_gc_time_stamp) {
1000 // Setting the time stamp here tells concurrent readers to look at
1001 // scan_top to know the maximum allowed address to look at.
1002
1003 // scan_top should be bottom for all regions except for the
1004 // retained old alloc region which should have scan_top == top
1005 HeapWord* st = _scan_top;
1006 guarantee(st == _bottom || st == _top, "invariant");
1007
1008 _gc_time_stamp = curr_gc_time_stamp;
1009 }
1010 }
1011
1012 void G1OffsetTableContigSpace::record_retained_region() {
1013 // scan_top is the maximum address where it's safe for the next gc to
1014 // scan this region.
1015 _scan_top = top();
1016 }
1017
1018 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1019 object_iterate(blk);
1020 }
1021
1022 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1023 HeapWord* p = bottom();
1024 while (p < top()) {
1025 if (block_is_obj(p)) {
1026 blk->do_object(oop(p));
1027 }
1028 p += block_size(p);
1029 }
1030 }
1031
1032 G1OffsetTableContigSpace::
1033 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1034 MemRegion mr) :
1035 _offsets(sharedOffsetArray, mr),
1036 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1037 _gc_time_stamp(0)
1038 {
1039 _offsets.set_space(this);
1040 }
1041
1042 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1043 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1044 _top = bottom();
1045 _scan_top = bottom();
1046 set_saved_mark_word(NULL);
1047 reset_bot();
1048 }