1 /*
2 * Copyright (c) 2001, 2019, 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_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/heapRegionBounds.inline.hpp"
32 #include "gc_implementation/g1/heapRegionRemSet.hpp"
33 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
34 #include "gc_implementation/g1/heapRegionTracer.hpp"
35 #include "gc_implementation/shared/liveRange.hpp"
36 #include "memory/genOopClosures.inline.hpp"
37 #include "memory/iterator.hpp"
38 #include "memory/space.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41
42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43
44 int HeapRegion::LogOfHRGrainBytes = 0;
45 int HeapRegion::LogOfHRGrainWords = 0;
46 size_t HeapRegion::GrainBytes = 0;
47 size_t HeapRegion::GrainWords = 0;
48 size_t HeapRegion::CardsPerRegion = 0;
49
50 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
51 HeapRegion* hr,
52 G1ParPushHeapRSClosure* cl,
53 CardTableModRefBS::PrecisionStyle precision) :
54 DirtyCardToOopClosure(hr, cl, precision, NULL),
55 _hr(hr), _rs_scan(cl), _g1(g1) { }
56
57 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
58 OopClosure* oc) :
59 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
60
61 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
62 HeapWord* bottom,
63 HeapWord* top) {
64 G1CollectedHeap* g1h = _g1;
65 size_t oop_size;
66 HeapWord* cur = bottom;
67
68 // Start filtering what we add to the remembered set. If the object is
69 // not considered dead, either because it is marked (in the mark bitmap)
70 // or it was allocated after marking finished, then we add it. Otherwise
71 // we can safely ignore the object.
72 if (!g1h->is_obj_dead(oop(cur), _hr)) {
73 oop_size = oop(cur)->oop_iterate(_rs_scan, mr);
74 } else {
75 oop_size = _hr->block_size(cur);
76 }
77
78 cur += oop_size;
79
80 if (cur < top) {
81 oop cur_oop = oop(cur);
82 oop_size = _hr->block_size(cur);
83 HeapWord* next_obj = cur + oop_size;
84 while (next_obj < top) {
85 // Keep filtering the remembered set.
86 if (!g1h->is_obj_dead(cur_oop, _hr)) {
87 // Bottom lies entirely below top, so we can call the
88 // non-memRegion version of oop_iterate below.
89 cur_oop->oop_iterate(_rs_scan);
90 }
91 cur = next_obj;
92 cur_oop = oop(cur);
93 oop_size = _hr->block_size(cur);
94 next_obj = cur + oop_size;
95 }
96
97 // Last object. Need to do dead-obj filtering here too.
98 if (!g1h->is_obj_dead(oop(cur), _hr)) {
99 oop(cur)->oop_iterate(_rs_scan, mr);
100 }
101 }
102 }
103
104 size_t HeapRegion::max_region_size() {
105 return HeapRegionBounds::max_size();
106 }
107
108 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
109 uintx region_size = G1HeapRegionSize;
110 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
111 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
112 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
113 (uintx) HeapRegionBounds::min_size());
114 }
115
116 int region_size_log = log2_long((jlong) region_size);
117 // Recalculate the region size to make sure it's a power of
118 // 2. This means that region_size is the largest power of 2 that's
119 // <= what we've calculated so far.
120 region_size = ((uintx)1 << region_size_log);
121
122 // Now make sure that we don't go over or under our limits.
123 if (region_size < HeapRegionBounds::min_size()) {
124 region_size = HeapRegionBounds::min_size();
125 } else if (region_size > HeapRegionBounds::max_size()) {
126 region_size = HeapRegionBounds::max_size();
127 }
128
129 // And recalculate the log.
130 region_size_log = log2_long((jlong) region_size);
131
132 // Now, set up the globals.
133 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
134 LogOfHRGrainBytes = region_size_log;
135
136 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
137 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
138
139 guarantee(GrainBytes == 0, "we should only set it once");
140 // The cast to int is safe, given that we've bounded region_size by
141 // MIN_REGION_SIZE and MAX_REGION_SIZE.
142 GrainBytes = (size_t)region_size;
143
144 guarantee(GrainWords == 0, "we should only set it once");
145 GrainWords = GrainBytes >> LogHeapWordSize;
146 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
147
148 guarantee(CardsPerRegion == 0, "we should only set it once");
149 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
150 }
151
152 void HeapRegion::reset_after_compaction() {
153 G1OffsetTableContigSpace::reset_after_compaction();
154 // After a compaction the mark bitmap is invalid, so we must
155 // treat all objects as being inside the unmarked area.
156 zero_marked_bytes();
157 init_top_at_mark_start();
158 }
159
160 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
161 assert(_humongous_start_region == NULL,
162 "we should have already filtered out humongous regions");
163 assert(_end == _orig_end,
164 "we should have already filtered out humongous regions");
165
166 _in_collection_set = false;
167
168 set_allocation_context(AllocationContext::system());
169 set_young_index_in_cset(-1);
170 uninstall_surv_rate_group();
171 set_free();
172 reset_pre_dummy_top();
173
174 if (!par) {
175 // If this is parallel, this will be done later.
176 HeapRegionRemSet* hrrs = rem_set();
177 if (locked) {
178 hrrs->clear_locked();
179 } else {
180 hrrs->clear();
181 }
182 _claimed = InitialClaimValue;
183 }
184 zero_marked_bytes();
185
186 _offsets.resize(HeapRegion::GrainWords);
187 init_top_at_mark_start();
188 if (clear_space) clear(SpaceDecorator::Mangle);
189 }
190
191 void HeapRegion::par_clear() {
192 assert(used() == 0, "the region should have been already cleared");
193 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
194 HeapRegionRemSet* hrrs = rem_set();
195 hrrs->clear();
196 CardTableModRefBS* ct_bs =
197 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
198 ct_bs->clear(MemRegion(bottom(), end()));
199 }
200
201 void HeapRegion::calc_gc_efficiency() {
202 // GC efficiency is the ratio of how much space would be
203 // reclaimed over how long we predict it would take to reclaim it.
204 G1CollectedHeap* g1h = G1CollectedHeap::heap();
205 G1CollectorPolicy* g1p = g1h->g1_policy();
206
207 // Retrieve a prediction of the elapsed time for this region for
208 // a mixed gc because the region will only be evacuated during a
209 // mixed gc.
210 double region_elapsed_time_ms =
211 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
212 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
213 }
214
215 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
216 assert(!isHumongous(), "sanity / pre-condition");
217 assert(end() == _orig_end,
218 "Should be normal before the humongous object allocation");
219 assert(top() == bottom(), "should be empty");
220 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
221 if (EnableJFR) {
222 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
223 }
224 _type.set_starts_humongous();
225 _humongous_start_region = this;
226
227 set_end(new_end);
228 _offsets.set_for_starts_humongous(new_top);
229 }
230
231 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
232 assert(!isHumongous(), "sanity / pre-condition");
233 assert(end() == _orig_end,
234 "Should be normal before the humongous object allocation");
235 assert(top() == bottom(), "should be empty");
236 assert(first_hr->startsHumongous(), "pre-condition");
237 if (EnableJFR) {
238 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
239 }
240 _type.set_continues_humongous();
241 _humongous_start_region = first_hr;
242 }
243
244 void HeapRegion::clear_humongous() {
245 assert(isHumongous(), "pre-condition");
246
247 if (startsHumongous()) {
248 assert(top() <= end(), "pre-condition");
249 set_end(_orig_end);
250 if (top() > end()) {
251 // at least one "continues humongous" region after it
252 set_top(end());
253 }
254 } else {
255 // continues humongous
256 assert(end() == _orig_end, "sanity");
257 }
258
259 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
260 _humongous_start_region = NULL;
261 }
262
263 bool HeapRegion::claimHeapRegion(jint claimValue) {
264 jint current = _claimed;
265 if (current != claimValue) {
266 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
267 if (res == current) {
268 return true;
269 }
270 }
271 return false;
272 }
273
274 HeapRegion::HeapRegion(uint hrm_index,
275 G1BlockOffsetSharedArray* sharedOffsetArray,
276 MemRegion mr) :
277 G1OffsetTableContigSpace(sharedOffsetArray, mr),
278 _hrm_index(hrm_index),
279 _allocation_context(AllocationContext::system()),
280 _humongous_start_region(NULL),
281 _in_collection_set(false),
282 _next_in_special_set(NULL), _orig_end(NULL),
283 _claimed(InitialClaimValue), _evacuation_failed(false),
284 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
285 _next_young_region(NULL),
286 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
287 #ifdef ASSERT
288 _containing_set(NULL),
289 #endif // ASSERT
290 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
291 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
292 _predicted_bytes_to_copy(0)
293 {
294 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
295 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
296
297 initialize(mr);
298 }
299
300 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
301 assert(_rem_set->is_empty(), "Remembered set must be empty");
302
303 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
304
305 _orig_end = mr.end();
306 hr_clear(false /*par*/, false /*clear_space*/);
307 set_top(bottom());
308 record_timestamp();
309 }
310
311 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
312 assert(EnableJFR, "sanity check");
313 HeapRegionTracer::send_region_type_change(_hrm_index,
314 get_trace_type(),
315 to,
316 (uintptr_t)bottom(),
317 used());
318 }
319
320
321 CompactibleSpace* HeapRegion::next_compaction_space() const {
322 return G1CollectedHeap::heap()->next_compaction_region(this);
323 }
324
325 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
326 bool during_conc_mark) {
327 // We always recreate the prev marking info and we'll explicitly
328 // mark all objects we find to be self-forwarded on the prev
329 // bitmap. So all objects need to be below PTAMS.
330 _prev_marked_bytes = 0;
331
332 if (during_initial_mark) {
333 // During initial-mark, we'll also explicitly mark all objects
334 // we find to be self-forwarded on the next bitmap. So all
335 // objects need to be below NTAMS.
336 _next_top_at_mark_start = top();
337 _next_marked_bytes = 0;
338 } else if (during_conc_mark) {
339 // During concurrent mark, all objects in the CSet (including
340 // the ones we find to be self-forwarded) are implicitly live.
341 // So all objects need to be above NTAMS.
342 _next_top_at_mark_start = bottom();
343 _next_marked_bytes = 0;
344 }
345 }
346
347 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
348 bool during_conc_mark,
349 size_t marked_bytes) {
350 assert(0 <= marked_bytes && marked_bytes <= used(),
351 err_msg("marked: " SIZE_FORMAT " used: " SIZE_FORMAT,
352 marked_bytes, used()));
353 _prev_top_at_mark_start = top();
354 _prev_marked_bytes = marked_bytes;
355 }
356
357 HeapWord*
358 HeapRegion::object_iterate_mem_careful(MemRegion mr,
359 ObjectClosure* cl) {
360 G1CollectedHeap* g1h = G1CollectedHeap::heap();
361 // We used to use "block_start_careful" here. But we're actually happy
362 // to update the BOT while we do this...
363 HeapWord* cur = block_start(mr.start());
364 mr = mr.intersection(used_region());
365 if (mr.is_empty()) return NULL;
366 // Otherwise, find the obj that extends onto mr.start().
367
368 assert(cur <= mr.start()
369 && (oop(cur)->klass_or_null() == NULL ||
370 cur + oop(cur)->size() > mr.start()),
371 "postcondition of block_start");
372 oop obj;
373 while (cur < mr.end()) {
374 obj = oop(cur);
375 if (obj->klass_or_null() == NULL) {
376 // Ran into an unparseable point.
377 return cur;
378 } else if (!g1h->is_obj_dead(obj)) {
379 cl->do_object(obj);
380 }
381 if (cl->abort()) return cur;
382 // The check above must occur before the operation below, since an
383 // abort might invalidate the "size" operation.
384 cur += block_size(cur);
385 }
386 return NULL;
387 }
388
389 HeapWord*
390 HeapRegion::
391 oops_on_card_seq_iterate_careful(MemRegion mr,
392 FilterOutOfRegionClosure* cl,
393 bool filter_young,
394 jbyte* card_ptr) {
395 // Currently, we should only have to clean the card if filter_young
396 // is true and vice versa.
397 if (filter_young) {
398 assert(card_ptr != NULL, "pre-condition");
399 } else {
400 assert(card_ptr == NULL, "pre-condition");
401 }
402 G1CollectedHeap* g1h = G1CollectedHeap::heap();
403
404 // If we're within a stop-world GC, then we might look at a card in a
405 // GC alloc region that extends onto a GC LAB, which may not be
406 // parseable. Stop such at the "scan_top" of the region.
407 if (g1h->is_gc_active()) {
408 mr = mr.intersection(MemRegion(bottom(), scan_top()));
409 } else {
410 mr = mr.intersection(used_region());
411 }
412 if (mr.is_empty()) return NULL;
413 // Otherwise, find the obj that extends onto mr.start().
414
415 // The intersection of the incoming mr (for the card) and the
416 // allocated part of the region is non-empty. This implies that
417 // we have actually allocated into this region. The code in
418 // G1CollectedHeap.cpp that allocates a new region sets the
419 // is_young tag on the region before allocating. Thus we
420 // safely know if this region is young.
421 if (is_young() && filter_young) {
422 return NULL;
423 }
424
425 assert(!is_young(), "check value of filter_young");
426
427 // We can only clean the card here, after we make the decision that
428 // the card is not young. And we only clean the card if we have been
429 // asked to (i.e., card_ptr != NULL).
430 if (card_ptr != NULL) {
431 *card_ptr = CardTableModRefBS::clean_card_val();
432 // We must complete this write before we do any of the reads below.
433 OrderAccess::storeload();
434 }
435
436 // Cache the boundaries of the memory region in some const locals
437 HeapWord* const start = mr.start();
438 HeapWord* const end = mr.end();
439
440 // We used to use "block_start_careful" here. But we're actually happy
441 // to update the BOT while we do this...
442 HeapWord* cur = block_start(start);
443 assert(cur <= start, "Postcondition");
444
445 oop obj;
446
447 HeapWord* next = cur;
448 do {
449 cur = next;
450 obj = oop(cur);
451 if (obj->klass_or_null() == NULL) {
452 // Ran into an unparseable point.
453 return cur;
454 }
455 // Otherwise...
456 next = cur + block_size(cur);
457 } while (next <= start);
458
459 // If we finish the above loop...We have a parseable object that
460 // begins on or before the start of the memory region, and ends
461 // inside or spans the entire region.
462 assert(cur <= start, "Loop postcondition");
463 assert(obj->klass_or_null() != NULL, "Loop postcondition");
464
465 do {
466 obj = oop(cur);
467 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
468 if (obj->klass_or_null() == NULL) {
469 // Ran into an unparseable point.
470 return cur;
471 }
472
473 // Advance the current pointer. "obj" still points to the object to iterate.
474 cur = cur + block_size(cur);
475
476 if (!g1h->is_obj_dead(obj)) {
477 // Non-objArrays are sometimes marked imprecise at the object start. We
478 // always need to iterate over them in full.
479 // We only iterate over object arrays in full if they are completely contained
480 // in the memory region.
481 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
482 obj->oop_iterate(cl);
483 } else {
484 obj->oop_iterate(cl, mr);
485 }
486 }
487 } while (cur < end);
488
489 return NULL;
490 }
491
492 // Code roots support
493
494 void HeapRegion::add_strong_code_root(nmethod* nm) {
495 HeapRegionRemSet* hrrs = rem_set();
496 hrrs->add_strong_code_root(nm);
497 }
498
499 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
500 assert_locked_or_safepoint(CodeCache_lock);
501 HeapRegionRemSet* hrrs = rem_set();
502 hrrs->add_strong_code_root_locked(nm);
503 }
504
505 void HeapRegion::remove_strong_code_root(nmethod* nm) {
506 HeapRegionRemSet* hrrs = rem_set();
507 hrrs->remove_strong_code_root(nm);
508 }
509
510 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
511 HeapRegionRemSet* hrrs = rem_set();
512 hrrs->strong_code_roots_do(blk);
513 }
514
515 class VerifyStrongCodeRootOopClosure: public OopClosure {
516 const HeapRegion* _hr;
517 nmethod* _nm;
518 bool _failures;
519 bool _has_oops_in_region;
520
521 template <class T> void do_oop_work(T* p) {
522 T heap_oop = oopDesc::load_heap_oop(p);
523 if (!oopDesc::is_null(heap_oop)) {
524 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
525
526 // Note: not all the oops embedded in the nmethod are in the
527 // current region. We only look at those which are.
528 if (_hr->is_in(obj)) {
529 // Object is in the region. Check that its less than top
530 if (_hr->top() <= (HeapWord*)obj) {
531 // Object is above top
532 gclog_or_tty->print_cr("Object " PTR_FORMAT " in region "
533 "[" PTR_FORMAT ", " PTR_FORMAT ") is above "
534 "top " PTR_FORMAT,
535 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
536 _failures = true;
537 return;
538 }
539 // Nmethod has at least one oop in the current region
540 _has_oops_in_region = true;
541 }
542 }
543 }
544
545 public:
546 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
547 _hr(hr), _failures(false), _has_oops_in_region(false) {}
548
549 void do_oop(narrowOop* p) { do_oop_work(p); }
550 void do_oop(oop* p) { do_oop_work(p); }
551
552 bool failures() { return _failures; }
553 bool has_oops_in_region() { return _has_oops_in_region; }
554 };
555
556 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
557 const HeapRegion* _hr;
558 bool _failures;
559 public:
560 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
561 _hr(hr), _failures(false) {}
562
563 void do_code_blob(CodeBlob* cb) {
564 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
565 if (nm != NULL) {
566 // Verify that the nemthod is live
567 if (!nm->is_alive()) {
568 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod "
569 PTR_FORMAT " in its strong code roots",
570 _hr->bottom(), _hr->end(), nm);
571 _failures = true;
572 } else {
573 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
574 nm->oops_do(&oop_cl);
575 if (!oop_cl.has_oops_in_region()) {
576 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod "
577 PTR_FORMAT " in its strong code roots "
578 "with no pointers into region",
579 _hr->bottom(), _hr->end(), nm);
580 _failures = true;
581 } else if (oop_cl.failures()) {
582 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has other "
583 "failures for nmethod " PTR_FORMAT,
584 _hr->bottom(), _hr->end(), nm);
585 _failures = true;
586 }
587 }
588 }
589 }
590
591 bool failures() { return _failures; }
592 };
593
594 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
595 if (!G1VerifyHeapRegionCodeRoots) {
596 // We're not verifying code roots.
597 return;
598 }
599 if (vo == VerifyOption_G1UseMarkWord) {
600 // Marking verification during a full GC is performed after class
601 // unloading, code cache unloading, etc so the strong code roots
602 // attached to each heap region are in an inconsistent state. They won't
603 // be consistent until the strong code roots are rebuilt after the
604 // actual GC. Skip verifying the strong code roots in this particular
605 // time.
606 assert(VerifyDuringGC, "only way to get here");
607 return;
608 }
609
610 HeapRegionRemSet* hrrs = rem_set();
611 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
612
613 // if this region is empty then there should be no entries
614 // on its strong code root list
615 if (is_empty()) {
616 if (strong_code_roots_length > 0) {
617 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is empty "
618 "but has " SIZE_FORMAT " code root entries",
619 bottom(), end(), strong_code_roots_length);
620 *failures = true;
621 }
622 return;
623 }
624
625 if (continuesHumongous()) {
626 if (strong_code_roots_length > 0) {
627 gclog_or_tty->print_cr("region " HR_FORMAT " is a continuation of a humongous "
628 "region but has " SIZE_FORMAT " code root entries",
629 HR_FORMAT_PARAMS(this), strong_code_roots_length);
630 *failures = true;
631 }
632 return;
633 }
634
635 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
636 strong_code_roots_do(&cb_cl);
637
638 if (cb_cl.failures()) {
639 *failures = true;
640 }
641 }
642
643 void HeapRegion::print() const { print_on(gclog_or_tty); }
644 void HeapRegion::print_on(outputStream* st) const {
645 st->print("AC%4u", allocation_context());
646 st->print(" %2s", get_short_type_str());
647 if (in_collection_set())
648 st->print(" CS");
649 else
650 st->print(" ");
651 st->print(" TS %5d", _gc_time_stamp);
652 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT,
653 prev_top_at_mark_start(), next_top_at_mark_start());
654 G1OffsetTableContigSpace::print_on(st);
655 }
656
657 class G1VerificationClosure : public OopClosure {
658 protected:
659 G1CollectedHeap* _g1h;
660 CardTableModRefBS* _bs;
661 oop _containing_obj;
662 bool _failures;
663 int _n_failures;
664 VerifyOption _vo;
665 public:
666 // _vo == UsePrevMarking -> use "prev" marking information,
667 // _vo == UseNextMarking -> use "next" marking information,
668 // _vo == UseMarkWord -> use mark word from object header.
669 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
670 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
671 _failures(false), _n_failures(0), _vo(vo)
672 {
673 BarrierSet* bs = _g1h->barrier_set();
674 if (bs->is_a(BarrierSet::CardTableModRef))
675 _bs = (CardTableModRefBS*)bs;
676 }
677
678 void set_containing_obj(oop obj) {
679 _containing_obj = obj;
680 }
681
682 bool failures() { return _failures; }
683 int n_failures() { return _n_failures; }
684
685 void print_object(outputStream* out, oop obj) {
686 #ifdef PRODUCT
687 Klass* k = obj->klass();
688 const char* class_name = InstanceKlass::cast(k)->external_name();
689 out->print_cr("class name %s", class_name);
690 #else // PRODUCT
691 obj->print_on(out);
692 #endif // PRODUCT
693 }
694 };
695
696 class VerifyLiveClosure : public G1VerificationClosure {
697 public:
698 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
699 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
700 virtual void do_oop(oop* p) { do_oop_work(p); }
701
702 template <class T>
703 void do_oop_work(T* p) {
704 assert(_containing_obj != NULL, "Precondition");
705 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
706 "Precondition");
707 verify_liveness(p);
708 }
709
710 template <class T>
711 void verify_liveness(T* p) {
712 T heap_oop = oopDesc::load_heap_oop(p);
713 if (!oopDesc::is_null(heap_oop)) {
714 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
715 bool failed = false;
716 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
717 MutexLockerEx x(ParGCRareEvent_lock,
718 Mutex::_no_safepoint_check_flag);
719
720 if (!_failures) {
721 gclog_or_tty->cr();
722 gclog_or_tty->print_cr("----------");
723 }
724 if (!_g1h->is_in_closed_subset(obj)) {
725 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
726 gclog_or_tty->print_cr("Field " PTR_FORMAT
727 " of live obj " PTR_FORMAT " in region "
728 "[" PTR_FORMAT ", " PTR_FORMAT ")",
729 p, (void*) _containing_obj,
730 from->bottom(), from->end());
731 print_object(gclog_or_tty, _containing_obj);
732 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " not in the heap",
733 (void*) obj);
734 } else {
735 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
736 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
737 gclog_or_tty->print_cr("Field " PTR_FORMAT
738 " of live obj " PTR_FORMAT " in region "
739 "[" PTR_FORMAT ", " PTR_FORMAT ")",
740 p, (void*) _containing_obj,
741 from->bottom(), from->end());
742 print_object(gclog_or_tty, _containing_obj);
743 gclog_or_tty->print_cr("points to dead obj " PTR_FORMAT " in region "
744 "[" PTR_FORMAT ", " PTR_FORMAT ")",
745 (void*) obj, to->bottom(), to->end());
746 print_object(gclog_or_tty, obj);
747 }
748 gclog_or_tty->print_cr("----------");
749 gclog_or_tty->flush();
750 _failures = true;
751 failed = true;
752 _n_failures++;
753 }
754 }
755 }
756 };
757
758 class VerifyRemSetClosure : public G1VerificationClosure {
759 public:
760 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
761 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
762 virtual void do_oop(oop* p) { do_oop_work(p); }
763
764 template <class T>
765 void do_oop_work(T* p) {
766 assert(_containing_obj != NULL, "Precondition");
767 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
768 "Precondition");
769 verify_remembered_set(p);
770 }
771
772 template <class T>
773 void verify_remembered_set(T* p) {
774 T heap_oop = oopDesc::load_heap_oop(p);
775 if (!oopDesc::is_null(heap_oop)) {
776 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
777 bool failed = false;
778 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
779 HeapRegion* to = _g1h->heap_region_containing(obj);
780 if (from != NULL && to != NULL &&
781 from != to &&
782 !to->isHumongous()) {
783 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
784 jbyte cv_field = *_bs->byte_for_const(p);
785 const jbyte dirty = CardTableModRefBS::dirty_card_val();
786
787 bool is_bad = !(from->is_young()
788 || to->rem_set()->contains_reference(p)
789 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
790 (_containing_obj->is_objArray() ?
791 cv_field == dirty
792 : cv_obj == dirty || cv_field == dirty));
793 if (is_bad) {
794 MutexLockerEx x(ParGCRareEvent_lock,
795 Mutex::_no_safepoint_check_flag);
796
797 if (!_failures) {
798 gclog_or_tty->cr();
799 gclog_or_tty->print_cr("----------");
800 }
801 gclog_or_tty->print_cr("Missing rem set entry:");
802 gclog_or_tty->print_cr("Field " PTR_FORMAT " "
803 "of obj " PTR_FORMAT ", "
804 "in region " HR_FORMAT,
805 p, (void*) _containing_obj,
806 HR_FORMAT_PARAMS(from));
807 _containing_obj->print_on(gclog_or_tty);
808 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " "
809 "in region " HR_FORMAT,
810 (void*) obj,
811 HR_FORMAT_PARAMS(to));
812 if (obj->is_oop()) {
813 obj->print_on(gclog_or_tty);
814 }
815 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
816 cv_obj, cv_field);
817 gclog_or_tty->print_cr("----------");
818 gclog_or_tty->flush();
819 _failures = true;
820 if (!failed) _n_failures++;
821 }
822 }
823 }
824 }
825 };
826
827 // This really ought to be commoned up into OffsetTableContigSpace somehow.
828 // We would need a mechanism to make that code skip dead objects.
829
830 void HeapRegion::verify(VerifyOption vo,
831 bool* failures) const {
832 G1CollectedHeap* g1 = G1CollectedHeap::heap();
833 *failures = false;
834 HeapWord* p = bottom();
835 HeapWord* prev_p = NULL;
836 VerifyLiveClosure vl_cl(g1, vo);
837 VerifyRemSetClosure vr_cl(g1, vo);
838 bool is_humongous = isHumongous();
839 bool do_bot_verify = !is_young();
840 size_t object_num = 0;
841 while (p < top()) {
842 oop obj = oop(p);
843 size_t obj_size = block_size(p);
844 object_num += 1;
845
846 if (is_humongous != g1->isHumongous(obj_size) &&
847 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
848 gclog_or_tty->print_cr("obj " PTR_FORMAT " is of %shumongous size ("
849 SIZE_FORMAT " words) in a %shumongous region",
850 p, g1->isHumongous(obj_size) ? "" : "non-",
851 obj_size, is_humongous ? "" : "non-");
852 *failures = true;
853 return;
854 }
855
856 // If it returns false, verify_for_object() will output the
857 // appropriate message.
858 if (do_bot_verify &&
859 !g1->is_obj_dead(obj, this) &&
860 !_offsets.verify_for_object(p, obj_size)) {
861 *failures = true;
862 return;
863 }
864
865 if (!g1->is_obj_dead_cond(obj, this, vo)) {
866 if (obj->is_oop()) {
867 Klass* klass = obj->klass();
868 bool is_metaspace_object = Metaspace::contains(klass) ||
869 (vo == VerifyOption_G1UsePrevMarking &&
870 ClassLoaderDataGraph::unload_list_contains(klass));
871 if (!is_metaspace_object) {
872 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
873 "not metadata", klass, (void *)obj);
874 *failures = true;
875 return;
876 } else if (!klass->is_klass()) {
877 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
878 "not a klass", klass, (void *)obj);
879 *failures = true;
880 return;
881 } else {
882 vl_cl.set_containing_obj(obj);
883 if (!g1->full_collection() || G1VerifyRSetsDuringFullGC) {
884 // verify liveness and rem_set
885 vr_cl.set_containing_obj(obj);
886 G1Mux2Closure mux(&vl_cl, &vr_cl);
887 obj->oop_iterate_no_header(&mux);
888
889 if (vr_cl.failures()) {
890 *failures = true;
891 }
892 if (G1MaxVerifyFailures >= 0 &&
893 vr_cl.n_failures() >= G1MaxVerifyFailures) {
894 return;
895 }
896 } else {
897 // verify only liveness
898 obj->oop_iterate_no_header(&vl_cl);
899 }
900 if (vl_cl.failures()) {
901 *failures = true;
902 }
903 if (G1MaxVerifyFailures >= 0 &&
904 vl_cl.n_failures() >= G1MaxVerifyFailures) {
905 return;
906 }
907 }
908 } else {
909 gclog_or_tty->print_cr(PTR_FORMAT " not an oop", (void *)obj);
910 *failures = true;
911 return;
912 }
913 }
914 prev_p = p;
915 p += obj_size;
916 }
917
918 if (p != top()) {
919 gclog_or_tty->print_cr("end of last object " PTR_FORMAT " "
920 "does not match top " PTR_FORMAT, p, top());
921 *failures = true;
922 return;
923 }
924
925 HeapWord* the_end = end();
926 assert(p == top(), "it should still hold");
927 // Do some extra BOT consistency checking for addresses in the
928 // range [top, end). BOT look-ups in this range should yield
929 // top. No point in doing that if top == end (there's nothing there).
930 if (p < the_end) {
931 // Look up top
932 HeapWord* addr_1 = p;
933 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
934 if (b_start_1 != p) {
935 gclog_or_tty->print_cr("BOT look up for top: " PTR_FORMAT " "
936 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
937 addr_1, b_start_1, p);
938 *failures = true;
939 return;
940 }
941
942 // Look up top + 1
943 HeapWord* addr_2 = p + 1;
944 if (addr_2 < the_end) {
945 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
946 if (b_start_2 != p) {
947 gclog_or_tty->print_cr("BOT look up for top + 1: " PTR_FORMAT " "
948 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
949 addr_2, b_start_2, p);
950 *failures = true;
951 return;
952 }
953 }
954
955 // Look up an address between top and end
956 size_t diff = pointer_delta(the_end, p) / 2;
957 HeapWord* addr_3 = p + diff;
958 if (addr_3 < the_end) {
959 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
960 if (b_start_3 != p) {
961 gclog_or_tty->print_cr("BOT look up for top + diff: " PTR_FORMAT " "
962 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
963 addr_3, b_start_3, p);
964 *failures = true;
965 return;
966 }
967 }
968
969 // Loook up end - 1
970 HeapWord* addr_4 = the_end - 1;
971 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
972 if (b_start_4 != p) {
973 gclog_or_tty->print_cr("BOT look up for end - 1: " PTR_FORMAT " "
974 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
975 addr_4, b_start_4, p);
976 *failures = true;
977 return;
978 }
979 }
980
981 if (is_humongous && object_num > 1) {
982 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is humongous "
983 "but has " SIZE_FORMAT ", objects",
984 bottom(), end(), object_num);
985 *failures = true;
986 return;
987 }
988
989 verify_strong_code_roots(vo, failures);
990 }
991
992 void HeapRegion::verify() const {
993 bool dummy = false;
994 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
995 }
996
997 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
998 G1CollectedHeap* g1 = G1CollectedHeap::heap();
999 *failures = false;
1000 HeapWord* p = bottom();
1001 HeapWord* prev_p = NULL;
1002 VerifyRemSetClosure vr_cl(g1, vo);
1003 while (p < top()) {
1004 oop obj = oop(p);
1005 size_t obj_size = block_size(p);
1006
1007 if (!g1->is_obj_dead_cond(obj, this, vo)) {
1008 if (obj->is_oop()) {
1009 vr_cl.set_containing_obj(obj);
1010 obj->oop_iterate_no_header(&vr_cl);
1011
1012 if (vr_cl.failures()) {
1013 *failures = true;
1014 }
1015 if (G1MaxVerifyFailures >= 0 &&
1016 vr_cl.n_failures() >= G1MaxVerifyFailures) {
1017 return;
1018 }
1019 } else {
1020 gclog_or_tty->print_cr(PTR_FORMAT " not an oop", p2i(obj));
1021 *failures = true;
1022 return;
1023 }
1024 }
1025
1026 prev_p = p;
1027 p += obj_size;
1028 }
1029 }
1030
1031 void HeapRegion::verify_rem_set() const {
1032 bool failures = false;
1033 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
1034 guarantee(!failures, "HeapRegion RemSet verification failed");
1035 }
1036
1037 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
1038 // away eventually.
1039
1040 void G1OffsetTableContigSpace::clear(bool mangle_space) {
1041 set_top(bottom());
1042 _scan_top = bottom();
1043 CompactibleSpace::clear(mangle_space);
1044 reset_bot();
1045 }
1046
1047 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
1048 Space::set_bottom(new_bottom);
1049 _offsets.set_bottom(new_bottom);
1050 }
1051
1052 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
1053 Space::set_end(new_end);
1054 _offsets.resize(new_end - bottom());
1055 }
1056
1057 void G1OffsetTableContigSpace::print() const {
1058 print_short();
1059 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1060 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1061 bottom(), top(), _offsets.threshold(), end());
1062 }
1063
1064 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
1065 return _offsets.initialize_threshold();
1066 }
1067
1068 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
1069 HeapWord* end) {
1070 _offsets.alloc_block(start, end);
1071 return _offsets.threshold();
1072 }
1073
1074 HeapWord* G1OffsetTableContigSpace::scan_top() const {
1075 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1076 HeapWord* local_top = top();
1077 OrderAccess::loadload();
1078 const unsigned local_time_stamp = _gc_time_stamp;
1079 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1080 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1081 return local_top;
1082 } else {
1083 return _scan_top;
1084 }
1085 }
1086
1087 void G1OffsetTableContigSpace::record_timestamp() {
1088 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1089 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
1090
1091 if (_gc_time_stamp < curr_gc_time_stamp) {
1092 // Setting the time stamp here tells concurrent readers to look at
1093 // scan_top to know the maximum allowed address to look at.
1094
1095 // scan_top should be bottom for all regions except for the
1096 // retained old alloc region which should have scan_top == top
1097 HeapWord* st = _scan_top;
1098 guarantee(st == _bottom || st == _top, "invariant");
1099
1100 _gc_time_stamp = curr_gc_time_stamp;
1101 }
1102 }
1103
1104 void G1OffsetTableContigSpace::record_retained_region() {
1105 // scan_top is the maximum address where it's safe for the next gc to
1106 // scan this region.
1107 _scan_top = top();
1108 }
1109
1110 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1111 object_iterate(blk);
1112 }
1113
1114 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1115 HeapWord* p = bottom();
1116 while (p < top()) {
1117 if (block_is_obj(p)) {
1118 blk->do_object(oop(p));
1119 }
1120 p += block_size(p);
1121 }
1122 }
1123
1124 #define block_is_always_obj(q) true
1125 void G1OffsetTableContigSpace::prepare_for_compaction(CompactPoint* cp) {
1126 SCAN_AND_FORWARD(cp, top, block_is_always_obj, block_size);
1127 }
1128 #undef block_is_always_obj
1129
1130 G1OffsetTableContigSpace::
1131 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1132 MemRegion mr) :
1133 _offsets(sharedOffsetArray, mr),
1134 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1135 _gc_time_stamp(0)
1136 {
1137 _offsets.set_space(this);
1138 }
1139
1140 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1141 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1142 _top = bottom();
1143 _scan_top = bottom();
1144 set_saved_mark_word(NULL);
1145 reset_bot();
1146 }
1147