1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. 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 "gc/shared/tlab_globals.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
32 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
33 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "gc/shenandoah/shenandoahVerifier.hpp"
36 #include "memory/allocation.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/compressedOops.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/orderAccess.hpp"
42 #include "runtime/threads.hpp"
43 #include "utilities/align.hpp"
44
45 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
46 #ifdef verify_oop
47 #undef verify_oop
48 #endif
49
50 static bool is_instance_ref_klass(Klass* k) {
51 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
52 }
53
54 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
55 public:
56 virtual bool discover_reference(oop obj, ReferenceType type) {
57 return true;
58 }
59 };
60
61 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
62 private:
63 const char* _phase;
64 ShenandoahVerifier::VerifyOptions _options;
65 ShenandoahVerifierStack* _stack;
66 ShenandoahHeap* _heap;
67 MarkBitMap* _map;
68 ShenandoahLivenessData* _ld;
69 void* _interior_loc;
70 oop _loc;
71
72 public:
73 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
74 const char* phase, ShenandoahVerifier::VerifyOptions options) :
75 _phase(phase),
76 _options(options),
77 _stack(stack),
78 _heap(ShenandoahHeap::heap()),
79 _map(map),
80 _ld(ld),
81 _interior_loc(nullptr),
82 _loc(nullptr) {
83 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
84 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
85 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
86 }
87 }
88
89 private:
90 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
91 if (!test) {
92 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
93 }
94 }
95
96 template <class T>
97 void do_oop_work(T* p) {
98 T o = RawAccess<>::oop_load(p);
99 if (!CompressedOops::is_null(o)) {
100 oop obj = CompressedOops::decode_not_null(o);
101 if (is_instance_ref_klass(obj->klass())) {
102 obj = ShenandoahForwarding::get_forwardee(obj);
103 }
104 // Single threaded verification can use faster non-atomic stack and bitmap
105 // methods.
106 //
107 // For performance reasons, only fully verify non-marked field values.
108 // We are here when the host object for *p is already marked.
109
110 if (_map->par_mark(obj)) {
111 verify_oop_at(p, obj);
112 _stack->push(ShenandoahVerifierTask(obj));
113 }
114 }
115 }
116
117 void verify_oop(oop obj) {
118 // Perform consistency checks with gradually decreasing safety level. This guarantees
119 // that failure report would not try to touch something that was not yet verified to be
120 // safe to process.
121
122 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
123 "oop must be in heap");
124 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
125 "oop must be aligned");
126
127 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
128 Klass* obj_klass = obj->klass_or_null();
129
130 // Verify that obj is not in dead space:
131 {
132 // Do this before touching obj->size()
133 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
134 "Object klass pointer should not be null");
135 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
136 "Object klass pointer must go to metaspace");
147 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
148 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
149 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
150 "Humongous object is in continuation that fits it");
151 }
152 }
153
154 // ------------ obj is safe at this point --------------
155
156 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
157 "Object should be in active region");
158
159 switch (_options._verify_liveness) {
160 case ShenandoahVerifier::_verify_liveness_disable:
161 // skip
162 break;
163 case ShenandoahVerifier::_verify_liveness_complete:
164 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
165 // fallthrough for fast failure for un-live regions:
166 case ShenandoahVerifier::_verify_liveness_conservative:
167 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
168 "Object must belong to region with live data");
169 break;
170 default:
171 assert(false, "Unhandled liveness verification");
172 }
173 }
174
175 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
176
177 ShenandoahHeapRegion* fwd_reg = nullptr;
178
179 if (obj != fwd) {
180 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
181 "Forwardee must be in heap");
182 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
183 "Forwardee is set");
184 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
185 "Forwardee must be aligned");
186
187 // Do this before touching fwd->size()
196 fwd_reg = _heap->heap_region_containing(fwd);
197
198 // Verify that forwardee is not in the dead space:
199 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
200 "Should have no humongous forwardees");
201
202 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
203 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
204 "Forwardee start should be within the region");
205 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
206 "Forwardee end should be within the region");
207
208 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
209 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
210 "Double forwarding");
211 } else {
212 fwd_reg = obj_reg;
213 }
214
215 // ------------ obj and fwd are safe at this point --------------
216
217 switch (_options._verify_marked) {
218 case ShenandoahVerifier::_verify_marked_disable:
219 // skip
220 break;
221 case ShenandoahVerifier::_verify_marked_incomplete:
222 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
223 "Must be marked in incomplete bitmap");
224 break;
225 case ShenandoahVerifier::_verify_marked_complete:
226 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
227 "Must be marked in complete bitmap");
228 break;
229 case ShenandoahVerifier::_verify_marked_complete_except_references:
230 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
231 "Must be marked in complete bitmap, except j.l.r.Reference referents");
232 break;
233 default:
234 assert(false, "Unhandled mark verification");
235 }
236
237 switch (_options._verify_forwarded) {
238 case ShenandoahVerifier::_verify_forwarded_disable:
239 // skip
240 break;
241 case ShenandoahVerifier::_verify_forwarded_none: {
242 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
243 "Should not be forwarded");
244 break;
245 }
246 case ShenandoahVerifier::_verify_forwarded_allow: {
247 if (obj != fwd) {
248 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
249 "Forwardee should be in another region");
250 }
296 void verify_oop_standalone(oop obj) {
297 _interior_loc = nullptr;
298 verify_oop(obj);
299 _interior_loc = nullptr;
300 }
301
302 /**
303 * Verify oop fields from this object.
304 * @param obj host object for verified fields
305 */
306 void verify_oops_from(oop obj) {
307 _loc = obj;
308 obj->oop_iterate(this);
309 _loc = nullptr;
310 }
311
312 virtual void do_oop(oop* p) { do_oop_work(p); }
313 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
314 };
315
316 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
317 private:
318 size_t _used, _committed, _garbage;
319 public:
320 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
321
322 void heap_region_do(ShenandoahHeapRegion* r) {
323 _used += r->used();
324 _garbage += r->garbage();
325 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
326 }
327
328 size_t used() { return _used; }
329 size_t committed() { return _committed; }
330 size_t garbage() { return _garbage; }
331 };
332
333 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
334 private:
335 ShenandoahHeap* _heap;
336 const char* _phase;
337 ShenandoahVerifier::VerifyRegions _regions;
338 public:
339 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
340 _heap(ShenandoahHeap::heap()),
341 _phase(phase),
342 _regions(regions) {};
343
344 void print_failure(ShenandoahHeapRegion* r, const char* label) {
345 ResourceMark rm;
346
347 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
348
349 stringStream ss;
350 r->print_on(&ss);
394 "Complete TAMS should not be larger than top");
395
396 verify(r, r->get_live_data_bytes() <= r->capacity(),
397 "Live data cannot be larger than capacity");
398
399 verify(r, r->garbage() <= r->capacity(),
400 "Garbage cannot be larger than capacity");
401
402 verify(r, r->used() <= r->capacity(),
403 "Used cannot be larger than capacity");
404
405 verify(r, r->get_shared_allocs() <= r->capacity(),
406 "Shared alloc count should not be larger than capacity");
407
408 verify(r, r->get_tlab_allocs() <= r->capacity(),
409 "TLAB alloc count should not be larger than capacity");
410
411 verify(r, r->get_gclab_allocs() <= r->capacity(),
412 "GCLAB alloc count should not be larger than capacity");
413
414 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
415 "Accurate accounting: shared + TLAB + GCLAB = used");
416
417 verify(r, !r->is_empty() || !r->has_live(),
418 "Empty regions should not have live data");
419
420 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
421 "Transitional: region flags and collection set agree");
422 }
423 };
424
425 class ShenandoahVerifierReachableTask : public WorkerTask {
426 private:
427 const char* _label;
428 ShenandoahVerifier::VerifyOptions _options;
429 ShenandoahHeap* _heap;
430 ShenandoahLivenessData* _ld;
431 MarkBitMap* _bitmap;
432 volatile size_t _processed;
433
434 public:
435 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
468 }
469 }
470
471 size_t processed = 0;
472
473 if (ShenandoahVerifyLevel >= 3) {
474 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
475 ShenandoahMessageBuffer("%s, Reachable", _label),
476 _options);
477 while (!stack.is_empty()) {
478 processed++;
479 ShenandoahVerifierTask task = stack.pop();
480 cl.verify_oops_from(task.obj());
481 }
482 }
483
484 Atomic::add(&_processed, processed, memory_order_relaxed);
485 }
486 };
487
488 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
489 private:
490 const char* _label;
491 ShenandoahVerifier::VerifyOptions _options;
492 ShenandoahHeap *_heap;
493 MarkBitMap* _bitmap;
494 ShenandoahLivenessData* _ld;
495 volatile size_t _claimed;
496 volatile size_t _processed;
497
498 public:
499 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
500 ShenandoahLivenessData* ld,
501 const char* label,
502 ShenandoahVerifier::VerifyOptions options) :
503 WorkerTask("Shenandoah Verifier Marked Objects"),
504 _label(label),
505 _options(options),
506 _heap(ShenandoahHeap::heap()),
507 _bitmap(bitmap),
508 _ld(ld),
509 _claimed(0),
510 _processed(0) {};
511
512 size_t processed() {
513 return Atomic::load(&_processed);
514 }
515
516 virtual void work(uint worker_id) {
517 ShenandoahVerifierStack stack;
518 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
519 ShenandoahMessageBuffer("%s, Marked", _label),
520 _options);
521
522 while (true) {
523 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
524 if (v < _heap->num_regions()) {
525 ShenandoahHeapRegion* r = _heap->get_region(v);
526 if (!r->is_humongous() && !r->is_trash()) {
527 work_regular(r, stack, cl);
528 } else if (r->is_humongous_start()) {
529 work_humongous(r, stack, cl);
530 }
531 } else {
532 break;
533 }
534 }
535 }
536
537 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
538 size_t processed = 0;
539 HeapWord* obj = r->bottom();
540 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
541 verify_and_follow(obj, stack, cl, &processed);
542 }
543 Atomic::add(&_processed, processed, memory_order_relaxed);
544 }
545
546 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
547 size_t processed = 0;
548 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
549 HeapWord* tams = ctx->top_at_mark_start(r);
550
551 // Bitmaps, before TAMS
552 if (tams > r->bottom()) {
553 HeapWord* start = r->bottom();
554 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
555
556 while (addr < tams) {
589 cl.verify_oops_from(obj);
590 (*processed)++;
591 }
592 while (!stack.is_empty()) {
593 ShenandoahVerifierTask task = stack.pop();
594 cl.verify_oops_from(task.obj());
595 (*processed)++;
596 }
597 }
598 };
599
600 class VerifyThreadGCState : public ThreadClosure {
601 private:
602 const char* const _label;
603 char const _expected;
604
605 public:
606 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
607 void do_thread(Thread* t) {
608 char actual = ShenandoahThreadLocalData::gc_state(t);
609 if (actual != _expected) {
610 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
611 }
612 }
613 };
614
615 void ShenandoahVerifier::verify_at_safepoint(const char *label,
616 VerifyForwarded forwarded, VerifyMarked marked,
617 VerifyCollectionSet cset,
618 VerifyLiveness liveness, VerifyRegions regions,
619 VerifyGCState gcstate) {
620 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
621 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
622
623 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
624
625 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
626 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
627
628 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
629
630 // GC state checks
631 {
632 char expected = -1;
633 bool enabled;
634 switch (gcstate) {
635 case _verify_gcstate_disable:
636 enabled = false;
637 break;
638 case _verify_gcstate_forwarded:
639 enabled = true;
640 expected = ShenandoahHeap::HAS_FORWARDED;
641 break;
642 case _verify_gcstate_evacuation:
643 enabled = true;
644 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
645 if (!_heap->is_stw_gc_in_progress()) {
646 // Only concurrent GC sets this.
647 expected |= ShenandoahHeap::WEAK_ROOTS;
648 }
649 break;
650 case _verify_gcstate_stable:
651 enabled = true;
652 expected = ShenandoahHeap::STABLE;
653 break;
654 case _verify_gcstate_stable_weakroots:
655 enabled = true;
656 expected = ShenandoahHeap::STABLE;
657 if (!_heap->is_stw_gc_in_progress()) {
658 // Only concurrent GC sets this.
659 expected |= ShenandoahHeap::WEAK_ROOTS;
660 }
661 break;
662 default:
663 enabled = false;
664 assert(false, "Unhandled gc-state verification");
665 }
666
667 if (enabled) {
668 char actual = _heap->gc_state();
669 if (actual != expected) {
670 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
671 }
672
673 VerifyThreadGCState vtgcs(label, expected);
674 Threads::java_threads_do(&vtgcs);
675 }
676 }
677
678 // Deactivate barriers temporarily: Verifier wants plain heap accesses
679 ShenandoahGCStateResetter resetter;
680
681 // Heap size checks
682 {
683 ShenandoahHeapLocker lock(_heap->lock());
684
685 ShenandoahCalculateRegionStatsClosure cl;
686 _heap->heap_region_iterate(&cl);
687 size_t heap_used = _heap->used();
688 guarantee(cl.used() == heap_used,
689 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
690 label,
691 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
692 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
693
694 size_t heap_committed = _heap->committed();
695 guarantee(cl.committed() == heap_committed,
696 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
697 label,
698 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
699 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
700 }
701
702 // Internal heap region checks
703 if (ShenandoahVerifyLevel >= 1) {
704 ShenandoahVerifyHeapRegionClosure cl(label, regions);
705 _heap->heap_region_iterate(&cl);
706 }
707
708 OrderAccess::fence();
709
710 if (UseTLAB) {
711 _heap->labs_make_parsable();
712 }
713
714 // Allocate temporary bitmap for storing marking wavefront:
715 _verification_bit_map->clear();
716
717 // Allocate temporary array for storing liveness data
718 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
719 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
720
721 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
722
723 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
724 // This verifies what application can see, since it only cares about reachable objects.
725 size_t count_reachable = 0;
726 if (ShenandoahVerifyLevel >= 2) {
727 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
728 _heap->workers()->run_task(&task);
729 count_reachable = task.processed();
730 }
731
732 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
733 // not the application, can see during the region scans. There is no reason to process the objects
734 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
735 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
736 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
737 // version
738
739 size_t count_marked = 0;
740 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
741 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
742 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
743 _heap->workers()->run_task(&task);
744 count_marked = task.processed();
745 } else {
746 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
747 }
748
749 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
750 // marked objects.
751
752 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
753 for (size_t i = 0; i < _heap->num_regions(); i++) {
754 ShenandoahHeapRegion* r = _heap->get_region(i);
755
756 juint verf_live = 0;
757 if (r->is_humongous()) {
758 // For humongous objects, test if start region is marked live, and if so,
759 // all humongous regions in that chain have live data equal to their "used".
760 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
761 if (start_live > 0) {
762 verf_live = (juint)(r->used() / HeapWordSize);
763 }
764 } else {
765 verf_live = Atomic::load(&ld[r->index()]);
766 }
767
768 size_t reg_live = r->get_live_data_words();
769 if (reg_live != verf_live) {
770 stringStream ss;
771 r->print_on(&ss);
772 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
773 label, reg_live, verf_live, ss.freeze());
774 }
775 }
776 }
777
778 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
779 label, ShenandoahVerifyLevel, count_reachable, count_marked);
780
781 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
782 }
783
784 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
785 verify_at_safepoint(
786 "Generic Verification",
787 _verify_forwarded_allow, // conservatively allow forwarded
788 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
789 _verify_cset_disable, // cset may be inconsistent
790 _verify_liveness_disable, // no reliable liveness data
791 _verify_regions_disable, // no reliable region data
792 _verify_gcstate_disable // no data about gcstate
793 );
794 }
795
796 void ShenandoahVerifier::verify_before_concmark() {
797 verify_at_safepoint(
798 "Before Mark",
799 _verify_forwarded_none, // UR should have fixed up
800 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
801 _verify_cset_none, // UR should have fixed this
802 _verify_liveness_disable, // no reliable liveness data
803 _verify_regions_notrash, // no trash regions
804 _verify_gcstate_stable // there are no forwarded objects
805 );
806 }
807
808 void ShenandoahVerifier::verify_after_concmark() {
809 verify_at_safepoint(
810 "After Mark",
811 _verify_forwarded_none, // no forwarded references
812 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
813 _verify_cset_none, // no references to cset anymore
814 _verify_liveness_complete, // liveness data must be complete here
815 _verify_regions_disable, // trash regions not yet recycled
816 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
817 );
818 }
819
820 void ShenandoahVerifier::verify_before_evacuation() {
821 verify_at_safepoint(
822 "Before Evacuation",
823 _verify_forwarded_none, // no forwarded references
824 _verify_marked_complete_except_references, // walk over marked objects too
825 _verify_cset_disable, // non-forwarded references to cset expected
826 _verify_liveness_complete, // liveness data must be complete here
827 _verify_regions_disable, // trash regions not yet recycled
828 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
829 );
830 }
831
832 void ShenandoahVerifier::verify_during_evacuation() {
833 verify_at_safepoint(
834 "During Evacuation",
835 _verify_forwarded_allow, // some forwarded references are allowed
836 _verify_marked_disable, // walk only roots
837 _verify_cset_disable, // some cset references are not forwarded yet
838 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
839 _verify_regions_disable, // trash regions not yet recycled
840 _verify_gcstate_evacuation // evacuation is in progress
841 );
842 }
843
844 void ShenandoahVerifier::verify_after_evacuation() {
845 verify_at_safepoint(
846 "After Evacuation",
847 _verify_forwarded_allow, // objects are still forwarded
848 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
849 _verify_cset_forwarded, // all cset refs are fully forwarded
850 _verify_liveness_disable, // no reliable liveness data anymore
851 _verify_regions_notrash, // trash regions have been recycled already
852 _verify_gcstate_forwarded // evacuation produced some forwarded objects
853 );
854 }
855
856 void ShenandoahVerifier::verify_before_updaterefs() {
857 verify_at_safepoint(
858 "Before Updating References",
859 _verify_forwarded_allow, // forwarded references allowed
860 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
861 _verify_cset_forwarded, // all cset refs are fully forwarded
862 _verify_liveness_disable, // no reliable liveness data anymore
863 _verify_regions_notrash, // trash regions have been recycled already
864 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
865 );
866 }
867
868 void ShenandoahVerifier::verify_after_updaterefs() {
869 verify_at_safepoint(
870 "After Updating References",
871 _verify_forwarded_none, // no forwarded references
872 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
873 _verify_cset_none, // no cset references, all updated
874 _verify_liveness_disable, // no reliable liveness data anymore
875 _verify_regions_nocset, // no cset regions, trash regions have appeared
876 _verify_gcstate_stable // update refs had cleaned up forwarded objects
877 );
878 }
879
880 void ShenandoahVerifier::verify_after_degenerated() {
881 verify_at_safepoint(
882 "After Degenerated GC",
883 _verify_forwarded_none, // all objects are non-forwarded
884 _verify_marked_complete, // all objects are marked in complete bitmap
885 _verify_cset_none, // no cset references
886 _verify_liveness_disable, // no reliable liveness data anymore
887 _verify_regions_notrash_nocset, // no trash, no cset
888 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
889 );
890 }
891
892 void ShenandoahVerifier::verify_before_fullgc() {
893 verify_at_safepoint(
894 "Before Full GC",
895 _verify_forwarded_allow, // can have forwarded objects
896 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
897 _verify_cset_disable, // cset might be foobared
898 _verify_liveness_disable, // no reliable liveness data anymore
899 _verify_regions_disable, // no reliable region data here
900 _verify_gcstate_disable // no reliable gcstate data
901 );
902 }
903
904 void ShenandoahVerifier::verify_after_fullgc() {
905 verify_at_safepoint(
906 "After Full GC",
907 _verify_forwarded_none, // all objects are non-forwarded
908 _verify_marked_complete, // all objects are marked in complete bitmap
909 _verify_cset_none, // no cset references
910 _verify_liveness_disable, // no reliable liveness data anymore
911 _verify_regions_notrash_nocset, // no trash, no cset
912 _verify_gcstate_stable // full gc cleaned up everything
913 );
914 }
915
916 class ShenandoahVerifyNoForwared : public OopClosure {
917 private:
918 template <class T>
919 void do_oop_work(T* p) {
920 T o = RawAccess<>::oop_load(p);
921 if (!CompressedOops::is_null(o)) {
922 oop obj = CompressedOops::decode_not_null(o);
923 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
924 if (obj != fwd) {
925 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
926 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
927 }
928 }
929 }
930
931 public:
932 void do_oop(narrowOop* p) { do_oop_work(p); }
933 void do_oop(oop* p) { do_oop_work(p); }
934 };
935
936 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
937 private:
938 template <class T>
939 void do_oop_work(T* p) {
940 T o = RawAccess<>::oop_load(p);
941 if (!CompressedOops::is_null(o)) {
942 oop obj = CompressedOops::decode_not_null(o);
943 ShenandoahHeap* heap = ShenandoahHeap::heap();
944
945 if (!heap->marking_context()->is_marked(obj)) {
946 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
947 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
948 }
949
950 if (heap->in_collection_set(obj)) {
951 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
952 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
953 }
954
955 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
956 if (obj != fwd) {
957 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
958 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
959 }
960 }
961 }
962
963 public:
964 void do_oop(narrowOop* p) { do_oop_work(p); }
965 void do_oop(oop* p) { do_oop_work(p); }
966 };
967
968 void ShenandoahVerifier::verify_roots_in_to_space() {
969 ShenandoahVerifyInToSpaceClosure cl;
970 ShenandoahRootVerifier::roots_do(&cl);
971 }
972
973 void ShenandoahVerifier::verify_roots_no_forwarded() {
974 ShenandoahVerifyNoForwared cl;
975 ShenandoahRootVerifier::roots_do(&cl);
976 }
|
1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/shared/tlab_globals.hpp"
28 #include "gc/shenandoah/shenandoahAsserts.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
30 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
31 #include "gc/shenandoah/shenandoahGeneration.hpp"
32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
34 #include "gc/shenandoah/shenandoahOldGeneration.hpp"
35 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
36 #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
37 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
38 #include "gc/shenandoah/shenandoahUtils.hpp"
39 #include "gc/shenandoah/shenandoahVerifier.hpp"
40 #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
41 #include "memory/allocation.hpp"
42 #include "memory/iterator.inline.hpp"
43 #include "memory/resourceArea.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/orderAccess.hpp"
47 #include "runtime/threads.hpp"
48 #include "utilities/align.hpp"
49
50 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
51 #ifdef verify_oop
52 #undef verify_oop
53 #endif
54
55 static bool is_instance_ref_klass(Klass* k) {
56 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
57 }
58
59 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
60 public:
61 virtual bool discover_reference(oop obj, ReferenceType type) {
62 return true;
63 }
64 };
65
66 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
67 private:
68 const char* _phase;
69 ShenandoahVerifier::VerifyOptions _options;
70 ShenandoahVerifierStack* _stack;
71 ShenandoahHeap* _heap;
72 MarkBitMap* _map;
73 ShenandoahLivenessData* _ld;
74 void* _interior_loc;
75 oop _loc;
76 ShenandoahGeneration* _generation;
77
78 public:
79 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
80 const char* phase, ShenandoahVerifier::VerifyOptions options) :
81 _phase(phase),
82 _options(options),
83 _stack(stack),
84 _heap(ShenandoahHeap::heap()),
85 _map(map),
86 _ld(ld),
87 _interior_loc(nullptr),
88 _loc(nullptr),
89 _generation(nullptr) {
90 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
91 options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty ||
92 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
93 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
94 }
95
96 if (_heap->mode()->is_generational()) {
97 _generation = _heap->active_generation();
98 assert(_generation != nullptr, "Expected active generation in this mode");
99 }
100 }
101
102 private:
103 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
104 if (!test) {
105 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
106 }
107 }
108
109 template <class T>
110 void do_oop_work(T* p) {
111 T o = RawAccess<>::oop_load(p);
112 if (!CompressedOops::is_null(o)) {
113 oop obj = CompressedOops::decode_not_null(o);
114 if (is_instance_ref_klass(obj->klass())) {
115 obj = ShenandoahForwarding::get_forwardee(obj);
116 }
117 // Single threaded verification can use faster non-atomic stack and bitmap
118 // methods.
119 //
120 // For performance reasons, only fully verify non-marked field values.
121 // We are here when the host object for *p is already marked.
122
123 // TODO: We should consider specializing this closure by generation ==/!= null,
124 // to avoid in_generation check on fast path here for non-generational mode.
125 if (in_generation(obj) && _map->par_mark(obj)) {
126 verify_oop_at(p, obj);
127 _stack->push(ShenandoahVerifierTask(obj));
128 }
129 }
130 }
131
132 bool in_generation(oop obj) {
133 if (_generation == nullptr) {
134 return true;
135 }
136
137 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
138 return _generation->contains(region);
139 }
140
141 void verify_oop(oop obj) {
142 // Perform consistency checks with gradually decreasing safety level. This guarantees
143 // that failure report would not try to touch something that was not yet verified to be
144 // safe to process.
145
146 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
147 "oop must be in heap");
148 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
149 "oop must be aligned");
150
151 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
152 Klass* obj_klass = obj->klass_or_null();
153
154 // Verify that obj is not in dead space:
155 {
156 // Do this before touching obj->size()
157 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
158 "Object klass pointer should not be null");
159 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
160 "Object klass pointer must go to metaspace");
171 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
172 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
173 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
174 "Humongous object is in continuation that fits it");
175 }
176 }
177
178 // ------------ obj is safe at this point --------------
179
180 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
181 "Object should be in active region");
182
183 switch (_options._verify_liveness) {
184 case ShenandoahVerifier::_verify_liveness_disable:
185 // skip
186 break;
187 case ShenandoahVerifier::_verify_liveness_complete:
188 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
189 // fallthrough for fast failure for un-live regions:
190 case ShenandoahVerifier::_verify_liveness_conservative:
191 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
192 (obj_reg->is_old() && _heap->active_generation()->is_young()),
193 "Object must belong to region with live data");
194 break;
195 default:
196 assert(false, "Unhandled liveness verification");
197 }
198 }
199
200 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
201
202 ShenandoahHeapRegion* fwd_reg = nullptr;
203
204 if (obj != fwd) {
205 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
206 "Forwardee must be in heap");
207 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
208 "Forwardee is set");
209 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
210 "Forwardee must be aligned");
211
212 // Do this before touching fwd->size()
221 fwd_reg = _heap->heap_region_containing(fwd);
222
223 // Verify that forwardee is not in the dead space:
224 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
225 "Should have no humongous forwardees");
226
227 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
228 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
229 "Forwardee start should be within the region");
230 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
231 "Forwardee end should be within the region");
232
233 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
234 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
235 "Double forwarding");
236 } else {
237 fwd_reg = obj_reg;
238 }
239
240 // ------------ obj and fwd are safe at this point --------------
241 // We allow for marked or old here for two reasons:
242 // 1. If this is a young collect, old objects wouldn't be marked. We've
243 // recently change the verifier traversal to only follow young objects
244 // during a young collect so this _shouldn't_ be necessary.
245 // 2. At present, we do not clear dead objects from the remembered set.
246 // Everything in the remembered set is old (ipso facto), so allowing for
247 // 'marked_or_old' covers the case of stale objects in rset.
248 // TODO: Just use 'is_marked' here.
249 switch (_options._verify_marked) {
250 case ShenandoahVerifier::_verify_marked_disable:
251 // skip
252 break;
253 case ShenandoahVerifier::_verify_marked_incomplete:
254 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked_or_old(obj),
255 "Must be marked in incomplete bitmap");
256 break;
257 case ShenandoahVerifier::_verify_marked_complete:
258 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
259 "Must be marked in complete bitmap");
260 break;
261 case ShenandoahVerifier::_verify_marked_complete_except_references:
262 case ShenandoahVerifier::_verify_marked_complete_satb_empty:
263 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
264 "Must be marked in complete bitmap, except j.l.r.Reference referents");
265 break;
266 default:
267 assert(false, "Unhandled mark verification");
268 }
269
270 switch (_options._verify_forwarded) {
271 case ShenandoahVerifier::_verify_forwarded_disable:
272 // skip
273 break;
274 case ShenandoahVerifier::_verify_forwarded_none: {
275 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
276 "Should not be forwarded");
277 break;
278 }
279 case ShenandoahVerifier::_verify_forwarded_allow: {
280 if (obj != fwd) {
281 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
282 "Forwardee should be in another region");
283 }
329 void verify_oop_standalone(oop obj) {
330 _interior_loc = nullptr;
331 verify_oop(obj);
332 _interior_loc = nullptr;
333 }
334
335 /**
336 * Verify oop fields from this object.
337 * @param obj host object for verified fields
338 */
339 void verify_oops_from(oop obj) {
340 _loc = obj;
341 obj->oop_iterate(this);
342 _loc = nullptr;
343 }
344
345 virtual void do_oop(oop* p) { do_oop_work(p); }
346 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
347 };
348
349 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
350 // a subset (e.g. the young generation or old generation) of the total heap.
351 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
352 private:
353 size_t _used, _committed, _garbage, _regions, _humongous_waste;
354 public:
355 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0) {};
356
357 void heap_region_do(ShenandoahHeapRegion* r) {
358 _used += r->used();
359 _garbage += r->garbage();
360 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
361 if (r->is_humongous()) {
362 _humongous_waste += r->free();
363 }
364 _regions++;
365 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
366 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
367 }
368
369 size_t used() { return _used; }
370 size_t committed() { return _committed; }
371 size_t garbage() { return _garbage; }
372 size_t regions() { return _regions; }
373 size_t waste() { return _humongous_waste; }
374
375 // span is the total memory affiliated with these stats (some of which is in use and other is available)
376 size_t span() { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
377 };
378
379 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
380 public:
381 ShenandoahCalculateRegionStatsClosure old;
382 ShenandoahCalculateRegionStatsClosure young;
383 ShenandoahCalculateRegionStatsClosure global;
384
385 void heap_region_do(ShenandoahHeapRegion* r) override {
386 switch (r->affiliation()) {
387 case FREE:
388 return;
389 case YOUNG_GENERATION:
390 young.heap_region_do(r);
391 global.heap_region_do(r);
392 break;
393 case OLD_GENERATION:
394 old.heap_region_do(r);
395 global.heap_region_do(r);
396 break;
397 default:
398 ShouldNotReachHere();
399 }
400 }
401
402 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
403 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
404 generation->name(),
405 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
406 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
407 }
408
409 static void validate_usage(const bool adjust_for_padding,
410 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
411 ShenandoahHeap* heap = ShenandoahHeap::heap();
412 size_t generation_used = generation->used();
413 size_t generation_used_regions = generation->used_regions();
414 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
415 size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
416 generation_used += pad;
417 }
418
419 guarantee(stats.used() == generation_used,
420 "%s: generation (%s) used size must be consistent: generation-used: " SIZE_FORMAT "%s, regions-used: " SIZE_FORMAT "%s",
421 label, generation->name(),
422 byte_size_in_proper_unit(generation_used), proper_unit_for_byte_size(generation_used),
423 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
424
425 guarantee(stats.regions() == generation_used_regions,
426 "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
427 label, generation->name(), generation->used_regions(), stats.regions());
428
429 size_t generation_capacity = generation->max_capacity();
430 size_t humongous_regions_promoted = 0;
431 guarantee(stats.span() <= generation_capacity,
432 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") must not exceed current capacity (" SIZE_FORMAT "%s)",
433 label, generation->name(), stats.regions(),
434 byte_size_in_proper_unit(generation_capacity), proper_unit_for_byte_size(generation_capacity));
435
436 size_t humongous_waste = generation->get_humongous_waste();
437 guarantee(stats.waste() == humongous_waste,
438 "%s: generation (%s) humongous waste must be consistent: generation: " SIZE_FORMAT "%s, regions: " SIZE_FORMAT "%s",
439 label, generation->name(),
440 byte_size_in_proper_unit(humongous_waste), proper_unit_for_byte_size(humongous_waste),
441 byte_size_in_proper_unit(stats.waste()), proper_unit_for_byte_size(stats.waste()));
442 }
443 };
444
445 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
446 private:
447 ShenandoahHeap* _heap;
448 const char* _phase;
449 ShenandoahVerifier::VerifyRegions _regions;
450 public:
451 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
452 _heap(ShenandoahHeap::heap()),
453 _phase(phase),
454 _regions(regions) {};
455
456 void print_failure(ShenandoahHeapRegion* r, const char* label) {
457 ResourceMark rm;
458
459 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
460
461 stringStream ss;
462 r->print_on(&ss);
506 "Complete TAMS should not be larger than top");
507
508 verify(r, r->get_live_data_bytes() <= r->capacity(),
509 "Live data cannot be larger than capacity");
510
511 verify(r, r->garbage() <= r->capacity(),
512 "Garbage cannot be larger than capacity");
513
514 verify(r, r->used() <= r->capacity(),
515 "Used cannot be larger than capacity");
516
517 verify(r, r->get_shared_allocs() <= r->capacity(),
518 "Shared alloc count should not be larger than capacity");
519
520 verify(r, r->get_tlab_allocs() <= r->capacity(),
521 "TLAB alloc count should not be larger than capacity");
522
523 verify(r, r->get_gclab_allocs() <= r->capacity(),
524 "GCLAB alloc count should not be larger than capacity");
525
526 verify(r, r->get_plab_allocs() <= r->capacity(),
527 "PLAB alloc count should not be larger than capacity");
528
529 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
530 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
531
532 verify(r, !r->is_empty() || !r->has_live(),
533 "Empty regions should not have live data");
534
535 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
536 "Transitional: region flags and collection set agree");
537 }
538 };
539
540 class ShenandoahVerifierReachableTask : public WorkerTask {
541 private:
542 const char* _label;
543 ShenandoahVerifier::VerifyOptions _options;
544 ShenandoahHeap* _heap;
545 ShenandoahLivenessData* _ld;
546 MarkBitMap* _bitmap;
547 volatile size_t _processed;
548
549 public:
550 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
583 }
584 }
585
586 size_t processed = 0;
587
588 if (ShenandoahVerifyLevel >= 3) {
589 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
590 ShenandoahMessageBuffer("%s, Reachable", _label),
591 _options);
592 while (!stack.is_empty()) {
593 processed++;
594 ShenandoahVerifierTask task = stack.pop();
595 cl.verify_oops_from(task.obj());
596 }
597 }
598
599 Atomic::add(&_processed, processed, memory_order_relaxed);
600 }
601 };
602
603 class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
604 public:
605 virtual void do_thread(Thread* thread) {
606 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
607 if (!queue.is_empty()) {
608 fatal("All SATB buffers should have been flushed during mark");
609 }
610 }
611 };
612
613 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
614 private:
615 const char* _label;
616 ShenandoahVerifier::VerifyOptions _options;
617 ShenandoahHeap *_heap;
618 MarkBitMap* _bitmap;
619 ShenandoahLivenessData* _ld;
620 volatile size_t _claimed;
621 volatile size_t _processed;
622 ShenandoahGeneration* _generation;
623
624 public:
625 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
626 ShenandoahLivenessData* ld,
627 const char* label,
628 ShenandoahVerifier::VerifyOptions options) :
629 WorkerTask("Shenandoah Verifier Marked Objects"),
630 _label(label),
631 _options(options),
632 _heap(ShenandoahHeap::heap()),
633 _bitmap(bitmap),
634 _ld(ld),
635 _claimed(0),
636 _processed(0),
637 _generation(nullptr) {
638 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
639 Threads::change_thread_claim_token();
640 }
641
642 if (_heap->mode()->is_generational()) {
643 _generation = _heap->active_generation();
644 assert(_generation != nullptr, "Expected active generation in this mode.");
645 }
646 };
647
648 size_t processed() {
649 return Atomic::load(&_processed);
650 }
651
652 virtual void work(uint worker_id) {
653 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
654 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
655 Threads::possibly_parallel_threads_do(true, &verify_satb);
656 }
657
658 ShenandoahVerifierStack stack;
659 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
660 ShenandoahMessageBuffer("%s, Marked", _label),
661 _options);
662
663 while (true) {
664 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
665 if (v < _heap->num_regions()) {
666 ShenandoahHeapRegion* r = _heap->get_region(v);
667 if (!in_generation(r)) {
668 continue;
669 }
670
671 if (!r->is_humongous() && !r->is_trash()) {
672 work_regular(r, stack, cl);
673 } else if (r->is_humongous_start()) {
674 work_humongous(r, stack, cl);
675 }
676 } else {
677 break;
678 }
679 }
680 }
681
682 bool in_generation(ShenandoahHeapRegion* r) {
683 return _generation == nullptr || _generation->contains(r);
684 }
685
686 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
687 size_t processed = 0;
688 HeapWord* obj = r->bottom();
689 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
690 verify_and_follow(obj, stack, cl, &processed);
691 }
692 Atomic::add(&_processed, processed, memory_order_relaxed);
693 }
694
695 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
696 size_t processed = 0;
697 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
698 HeapWord* tams = ctx->top_at_mark_start(r);
699
700 // Bitmaps, before TAMS
701 if (tams > r->bottom()) {
702 HeapWord* start = r->bottom();
703 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
704
705 while (addr < tams) {
738 cl.verify_oops_from(obj);
739 (*processed)++;
740 }
741 while (!stack.is_empty()) {
742 ShenandoahVerifierTask task = stack.pop();
743 cl.verify_oops_from(task.obj());
744 (*processed)++;
745 }
746 }
747 };
748
749 class VerifyThreadGCState : public ThreadClosure {
750 private:
751 const char* const _label;
752 char const _expected;
753
754 public:
755 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
756 void do_thread(Thread* t) {
757 char actual = ShenandoahThreadLocalData::gc_state(t);
758 if (!verify_gc_state(actual, _expected)) {
759 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
760 }
761 }
762
763 static bool verify_gc_state(char actual, char expected) {
764 // Old generation marking is allowed in all states.
765 if (ShenandoahHeap::heap()->mode()->is_generational()) {
766 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
767 } else {
768 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
769 return (actual == expected);
770 }
771 }
772 };
773
774 void ShenandoahVerifier::verify_at_safepoint(const char* label,
775 VerifyRememberedSet remembered,
776 VerifyForwarded forwarded, VerifyMarked marked,
777 VerifyCollectionSet cset,
778 VerifyLiveness liveness, VerifyRegions regions,
779 VerifySize sizeness,
780 VerifyGCState gcstate) {
781 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
782 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
783
784 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
785
786 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
787 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
788
789 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
790
791 // GC state checks
792 {
793 char expected = -1;
794 bool enabled;
795 switch (gcstate) {
796 case _verify_gcstate_disable:
797 enabled = false;
798 break;
799 case _verify_gcstate_forwarded:
800 enabled = true;
801 expected = ShenandoahHeap::HAS_FORWARDED;
802 break;
803 case _verify_gcstate_evacuation:
804 enabled = true;
805 expected = ShenandoahHeap::EVACUATION;
806 if (!_heap->is_stw_gc_in_progress()) {
807 // Only concurrent GC sets this.
808 expected |= ShenandoahHeap::WEAK_ROOTS;
809 }
810 break;
811 case _verify_gcstate_updating:
812 enabled = true;
813 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
814 break;
815 case _verify_gcstate_stable:
816 enabled = true;
817 expected = ShenandoahHeap::STABLE;
818 break;
819 case _verify_gcstate_stable_weakroots:
820 enabled = true;
821 expected = ShenandoahHeap::STABLE;
822 if (!_heap->is_stw_gc_in_progress()) {
823 // Only concurrent GC sets this.
824 expected |= ShenandoahHeap::WEAK_ROOTS;
825 }
826 break;
827 default:
828 enabled = false;
829 assert(false, "Unhandled gc-state verification");
830 }
831
832 if (enabled) {
833 char actual = _heap->gc_state();
834
835 bool is_marking = (actual & ShenandoahHeap::MARKING);
836 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
837 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
838
839 // Old generation marking is allowed in all states.
840 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
841 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
842 }
843
844 VerifyThreadGCState vtgcs(label, expected);
845 Threads::java_threads_do(&vtgcs);
846 }
847 }
848
849 // Deactivate barriers temporarily: Verifier wants plain heap accesses
850 ShenandoahGCStateResetter resetter;
851
852 // Heap size checks
853 {
854 ShenandoahHeapLocker lock(_heap->lock());
855
856 ShenandoahCalculateRegionStatsClosure cl;
857 _heap->heap_region_iterate(&cl);
858 size_t heap_used;
859 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
860 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
861 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
862 } else if (sizeness != _verify_size_disable) {
863 heap_used = _heap->used();
864 }
865 if (sizeness != _verify_size_disable) {
866 guarantee(cl.used() == heap_used,
867 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
868 label,
869 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
870 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
871 }
872 size_t heap_committed = _heap->committed();
873 guarantee(cl.committed() == heap_committed,
874 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
875 label,
876 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
877 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
878 }
879
880 log_debug(gc)("Safepoint verification finished heap usage verification");
881
882 ShenandoahGeneration* generation;
883 if (_heap->mode()->is_generational()) {
884 generation = _heap->active_generation();
885 guarantee(generation != nullptr, "Need to know which generation to verify.");
886 } else {
887 generation = nullptr;
888 }
889
890 if (generation != nullptr) {
891 ShenandoahHeapLocker lock(_heap->lock());
892
893 switch (remembered) {
894 case _verify_remembered_disable:
895 break;
896 case _verify_remembered_before_marking:
897 log_debug(gc)("Safepoint verification of remembered set at mark");
898 verify_rem_set_before_mark();
899 break;
900 case _verify_remembered_before_updating_references:
901 log_debug(gc)("Safepoint verification of remembered set at update ref");
902 verify_rem_set_before_update_ref();
903 break;
904 case _verify_remembered_after_full_gc:
905 log_debug(gc)("Safepoint verification of remembered set after full gc");
906 verify_rem_set_after_full_gc();
907 break;
908 default:
909 fatal("Unhandled remembered set verification mode");
910 }
911
912 ShenandoahGenerationStatsClosure cl;
913 _heap->heap_region_iterate(&cl);
914
915 if (LogTarget(Debug, gc)::is_enabled()) {
916 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
917 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
918 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
919 }
920 if (sizeness == _verify_size_adjusted_for_padding) {
921 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
922 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
923 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
924 } else if (sizeness == _verify_size_exact) {
925 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
926 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
927 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
928 }
929 // else: sizeness must equal _verify_size_disable
930 }
931
932 log_debug(gc)("Safepoint verification finished remembered set verification");
933
934 // Internal heap region checks
935 if (ShenandoahVerifyLevel >= 1) {
936 ShenandoahVerifyHeapRegionClosure cl(label, regions);
937 if (generation != nullptr) {
938 generation->heap_region_iterate(&cl);
939 } else {
940 _heap->heap_region_iterate(&cl);
941 }
942 }
943
944 log_debug(gc)("Safepoint verification finished heap region closure verification");
945
946 OrderAccess::fence();
947
948 if (UseTLAB) {
949 _heap->labs_make_parsable();
950 }
951
952 // Allocate temporary bitmap for storing marking wavefront:
953 _verification_bit_map->clear();
954
955 // Allocate temporary array for storing liveness data
956 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
957 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
958
959 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
960
961 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
962 // This verifies what application can see, since it only cares about reachable objects.
963 size_t count_reachable = 0;
964 if (ShenandoahVerifyLevel >= 2) {
965 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
966 _heap->workers()->run_task(&task);
967 count_reachable = task.processed();
968 }
969
970 log_debug(gc)("Safepoint verification finished getting initial reachable set");
971
972 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
973 // not the application, can see during the region scans. There is no reason to process the objects
974 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
975 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
976 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
977 // version
978
979 size_t count_marked = 0;
980 if (ShenandoahVerifyLevel >= 4 &&
981 (marked == _verify_marked_complete ||
982 marked == _verify_marked_complete_except_references ||
983 marked == _verify_marked_complete_satb_empty)) {
984 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
985 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
986 _heap->workers()->run_task(&task);
987 count_marked = task.processed();
988 } else {
989 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
990 }
991
992 log_debug(gc)("Safepoint verification finished walking marked objects");
993
994 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
995 // marked objects.
996
997 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
998 for (size_t i = 0; i < _heap->num_regions(); i++) {
999 ShenandoahHeapRegion* r = _heap->get_region(i);
1000 if (generation != nullptr && !generation->contains(r)) {
1001 continue;
1002 }
1003
1004 juint verf_live = 0;
1005 if (r->is_humongous()) {
1006 // For humongous objects, test if start region is marked live, and if so,
1007 // all humongous regions in that chain have live data equal to their "used".
1008 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1009 if (start_live > 0) {
1010 verf_live = (juint)(r->used() / HeapWordSize);
1011 }
1012 } else {
1013 verf_live = Atomic::load(&ld[r->index()]);
1014 }
1015
1016 size_t reg_live = r->get_live_data_words();
1017 if (reg_live != verf_live) {
1018 stringStream ss;
1019 r->print_on(&ss);
1020 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
1021 label, reg_live, verf_live, ss.freeze());
1022 }
1023 }
1024 }
1025
1026 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1027
1028
1029 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
1030 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1031
1032 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1033 }
1034
1035 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1036 verify_at_safepoint(
1037 "Generic Verification",
1038 _verify_remembered_disable, // do not verify remembered set
1039 _verify_forwarded_allow, // conservatively allow forwarded
1040 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1041 _verify_cset_disable, // cset may be inconsistent
1042 _verify_liveness_disable, // no reliable liveness data
1043 _verify_regions_disable, // no reliable region data
1044 _verify_size_exact, // expect generation and heap sizes to match exactly
1045 _verify_gcstate_disable // no data about gcstate
1046 );
1047 }
1048
1049 void ShenandoahVerifier::verify_before_concmark() {
1050 verify_at_safepoint(
1051 "Before Mark",
1052 _verify_remembered_before_marking,
1053 // verify read-only remembered set from bottom() to top()
1054 _verify_forwarded_none, // UR should have fixed up
1055 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1056 _verify_cset_none, // UR should have fixed this
1057 _verify_liveness_disable, // no reliable liveness data
1058 _verify_regions_notrash, // no trash regions
1059 _verify_size_exact, // expect generation and heap sizes to match exactly
1060 _verify_gcstate_stable // there are no forwarded objects
1061 );
1062 }
1063
1064 void ShenandoahVerifier::verify_after_concmark() {
1065 verify_at_safepoint(
1066 "After Mark",
1067 _verify_remembered_disable, // do not verify remembered set
1068 _verify_forwarded_none, // no forwarded references
1069 _verify_marked_complete_satb_empty,
1070 // bitmaps as precise as we can get, except dangling j.l.r.Refs
1071 _verify_cset_none, // no references to cset anymore
1072 _verify_liveness_complete, // liveness data must be complete here
1073 _verify_regions_disable, // trash regions not yet recycled
1074 _verify_size_exact, // expect generation and heap sizes to match exactly
1075 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1076 );
1077 }
1078
1079 void ShenandoahVerifier::verify_before_evacuation() {
1080 verify_at_safepoint(
1081 "Before Evacuation",
1082 _verify_remembered_disable, // do not verify remembered set
1083 _verify_forwarded_none, // no forwarded references
1084 _verify_marked_complete_except_references, // walk over marked objects too
1085 _verify_cset_disable, // non-forwarded references to cset expected
1086 _verify_liveness_complete, // liveness data must be complete here
1087 _verify_regions_disable, // trash regions not yet recycled
1088 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1089 // for promote in place padding
1090 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1091 );
1092 }
1093
1094 void ShenandoahVerifier::verify_during_evacuation() {
1095 verify_at_safepoint(
1096 "During Evacuation",
1097 _verify_remembered_disable, // do not verify remembered set
1098 _verify_forwarded_allow, // some forwarded references are allowed
1099 _verify_marked_disable, // walk only roots
1100 _verify_cset_disable, // some cset references are not forwarded yet
1101 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1102 _verify_regions_disable, // trash regions not yet recycled
1103 _verify_size_disable, // we don't know how much of promote-in-place work has been completed
1104 _verify_gcstate_evacuation // evacuation is in progress
1105 );
1106 }
1107
1108 void ShenandoahVerifier::verify_after_evacuation() {
1109 verify_at_safepoint(
1110 "After Evacuation",
1111 _verify_remembered_disable, // do not verify remembered set
1112 _verify_forwarded_allow, // objects are still forwarded
1113 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1114 _verify_cset_forwarded, // all cset refs are fully forwarded
1115 _verify_liveness_disable, // no reliable liveness data anymore
1116 _verify_regions_notrash, // trash regions have been recycled already
1117 _verify_size_exact, // expect generation and heap sizes to match exactly
1118 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1119 );
1120 }
1121
1122 void ShenandoahVerifier::verify_before_updaterefs() {
1123 verify_at_safepoint(
1124 "Before Updating References",
1125 _verify_remembered_before_updating_references, // verify read-write remembered set
1126 _verify_forwarded_allow, // forwarded references allowed
1127 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1128 _verify_cset_forwarded, // all cset refs are fully forwarded
1129 _verify_liveness_disable, // no reliable liveness data anymore
1130 _verify_regions_notrash, // trash regions have been recycled already
1131 _verify_size_exact, // expect generation and heap sizes to match exactly
1132 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1133 );
1134 }
1135
1136 // We have not yet cleanup (reclaimed) the collection set
1137 void ShenandoahVerifier::verify_after_updaterefs() {
1138 verify_at_safepoint(
1139 "After Updating References",
1140 _verify_remembered_disable, // do not verify remembered set
1141 _verify_forwarded_none, // no forwarded references
1142 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1143 _verify_cset_none, // no cset references, all updated
1144 _verify_liveness_disable, // no reliable liveness data anymore
1145 _verify_regions_nocset, // no cset regions, trash regions have appeared
1146 _verify_size_exact, // expect generation and heap sizes to match exactly
1147 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1148 );
1149 }
1150
1151 void ShenandoahVerifier::verify_after_degenerated() {
1152 verify_at_safepoint(
1153 "After Degenerated GC",
1154 _verify_remembered_disable, // do not verify remembered set
1155 _verify_forwarded_none, // all objects are non-forwarded
1156 _verify_marked_complete, // all objects are marked in complete bitmap
1157 _verify_cset_none, // no cset references
1158 _verify_liveness_disable, // no reliable liveness data anymore
1159 _verify_regions_notrash_nocset, // no trash, no cset
1160 _verify_size_exact, // expect generation and heap sizes to match exactly
1161 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1162 );
1163 }
1164
1165 void ShenandoahVerifier::verify_before_fullgc() {
1166 verify_at_safepoint(
1167 "Before Full GC",
1168 _verify_remembered_disable, // do not verify remembered set
1169 _verify_forwarded_allow, // can have forwarded objects
1170 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1171 _verify_cset_disable, // cset might be foobared
1172 _verify_liveness_disable, // no reliable liveness data anymore
1173 _verify_regions_disable, // no reliable region data here
1174 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1175 _verify_gcstate_disable // no reliable gcstate data
1176 );
1177 }
1178
1179 void ShenandoahVerifier::verify_after_fullgc() {
1180 verify_at_safepoint(
1181 "After Full GC",
1182 _verify_remembered_after_full_gc, // verify read-write remembered set
1183 _verify_forwarded_none, // all objects are non-forwarded
1184 _verify_marked_complete, // all objects are marked in complete bitmap
1185 _verify_cset_none, // no cset references
1186 _verify_liveness_disable, // no reliable liveness data anymore
1187 _verify_regions_notrash_nocset, // no trash, no cset
1188 _verify_size_exact, // expect generation and heap sizes to match exactly
1189 _verify_gcstate_stable // full gc cleaned up everything
1190 );
1191 }
1192
1193 // TODO: Why this closure does not visit metadata?
1194 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1195 private:
1196 template <class T>
1197 void do_oop_work(T* p) {
1198 T o = RawAccess<>::oop_load(p);
1199 if (!CompressedOops::is_null(o)) {
1200 oop obj = CompressedOops::decode_not_null(o);
1201 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1202 if (obj != fwd) {
1203 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1204 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1205 }
1206 }
1207 }
1208
1209 public:
1210 void do_oop(narrowOop* p) { do_oop_work(p); }
1211 void do_oop(oop* p) { do_oop_work(p); }
1212 };
1213
1214 // TODO: Why this closure does not visit metadata?
1215 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1216 private:
1217 template <class T>
1218 void do_oop_work(T* p) {
1219 T o = RawAccess<>::oop_load(p);
1220 if (!CompressedOops::is_null(o)) {
1221 oop obj = CompressedOops::decode_not_null(o);
1222 ShenandoahHeap* heap = ShenandoahHeap::heap();
1223
1224 if (!heap->marking_context()->is_marked_or_old(obj)) {
1225 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1226 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1227 }
1228
1229 if (heap->in_collection_set(obj)) {
1230 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1231 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1232 }
1233
1234 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1235 if (obj != fwd) {
1236 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1237 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1238 }
1239 }
1240 }
1241
1242 public:
1243 void do_oop(narrowOop* p) { do_oop_work(p); }
1244 void do_oop(oop* p) { do_oop_work(p); }
1245 };
1246
1247 void ShenandoahVerifier::verify_roots_in_to_space() {
1248 ShenandoahVerifyInToSpaceClosure cl;
1249 ShenandoahRootVerifier::roots_do(&cl);
1250 }
1251
1252 void ShenandoahVerifier::verify_roots_no_forwarded() {
1253 ShenandoahVerifyNoForwared cl;
1254 ShenandoahRootVerifier::roots_do(&cl);
1255 }
1256
1257 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1258 protected:
1259 bool const _init_mark;
1260 ShenandoahHeap* const _heap;
1261 RememberedScanner* const _scanner;
1262
1263 public:
1264 // Argument distinguishes between initial mark or start of update refs verification.
1265 ShenandoahVerifyRemSetClosure(bool init_mark) :
1266 _init_mark(init_mark),
1267 _heap(ShenandoahHeap::heap()),
1268 _scanner(_heap->card_scan()) {}
1269
1270 template<class T>
1271 inline void work(T* p) {
1272 T o = RawAccess<>::oop_load(p);
1273 if (!CompressedOops::is_null(o)) {
1274 oop obj = CompressedOops::decode_not_null(o);
1275 if (_heap->is_in_young(obj)) {
1276 size_t card_index = _scanner->card_index_for_addr((HeapWord*) p);
1277 if (_init_mark && !_scanner->is_card_dirty(card_index)) {
1278 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1279 "Verify init-mark remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1280 } else if (!_init_mark && !_scanner->is_write_card_dirty(card_index)) {
1281 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1282 "Verify init-update-refs remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1283 }
1284 }
1285 }
1286 }
1287
1288 virtual void do_oop(narrowOop* p) { work(p); }
1289 virtual void do_oop(oop* p) { work(p); }
1290 };
1291
1292 void ShenandoahVerifier::help_verify_region_rem_set(ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx, HeapWord* from,
1293 HeapWord* top, HeapWord* registration_watermark, const char* message) {
1294 RememberedScanner* scanner = _heap->card_scan();
1295 ShenandoahVerifyRemSetClosure check_interesting_pointers(false);
1296
1297 HeapWord* obj_addr = from;
1298 if (r->is_humongous_start()) {
1299 oop obj = cast_to_oop(obj_addr);
1300 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1301 size_t card_index = scanner->card_index_for_addr(obj_addr);
1302 // For humongous objects, the typical object is an array, so the following checks may be overkill
1303 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1304 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1305 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1306 obj->oop_iterate(&check_interesting_pointers);
1307 }
1308 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1309 }
1310 // else, this humongous object is not live so no need to verify its internal pointers
1311
1312 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1313 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1314 "object not properly registered", __FILE__, __LINE__);
1315 }
1316 } else if (!r->is_humongous()) {
1317 while (obj_addr < top) {
1318 oop obj = cast_to_oop(obj_addr);
1319 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1320 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1321 size_t card_index = scanner->card_index_for_addr(obj_addr);
1322 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1323 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1324 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1325 obj->oop_iterate(&check_interesting_pointers);
1326 }
1327 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1328
1329 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1330 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1331 "object not properly registered", __FILE__, __LINE__);
1332 }
1333 obj_addr += obj->size();
1334 } else {
1335 // This object is not live so we don't verify dirty cards contained therein
1336 HeapWord* tams = ctx->top_at_mark_start(r);
1337 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1338 }
1339 }
1340 }
1341 }
1342
1343 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1344 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1345 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1346 // restore them until the start of evacuation.
1347 void ShenandoahVerifier::verify_rem_set_before_mark() {
1348 shenandoah_assert_safepoint();
1349 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1350
1351 ShenandoahRegionIterator iterator;
1352 RememberedScanner* scanner = _heap->card_scan();
1353 ShenandoahVerifyRemSetClosure check_interesting_pointers(true);
1354 ShenandoahMarkingContext* ctx;
1355
1356 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1357 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1358
1359 if (old_generation->is_mark_complete() || _heap->active_generation()->is_global()) {
1360 ctx = _heap->complete_marking_context();
1361 } else {
1362 ctx = nullptr;
1363 }
1364
1365 while (iterator.has_next()) {
1366 ShenandoahHeapRegion* r = iterator.next();
1367 if (r == nullptr) {
1368 // TODO: Can this really happen?
1369 break;
1370 }
1371
1372 HeapWord* tams = (ctx != nullptr) ? ctx->top_at_mark_start(r) : nullptr;
1373
1374 // TODO: Is this replaceable with call to help_verify_region_rem_set?
1375
1376 if (r->is_old() && r->is_active()) {
1377 HeapWord* obj_addr = r->bottom();
1378 if (r->is_humongous_start()) {
1379 oop obj = cast_to_oop(obj_addr);
1380 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1381 // For humongous objects, the typical object is an array, so the following checks may be overkill
1382 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1383 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1384 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1385 obj->oop_iterate(&check_interesting_pointers);
1386 }
1387 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1388 }
1389 // else, this humongous object is not marked so no need to verify its internal pointers
1390 if (!scanner->verify_registration(obj_addr, ctx)) {
1391 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1392 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1393 }
1394 } else if (!r->is_humongous()) {
1395 HeapWord* top = r->top();
1396 while (obj_addr < top) {
1397 oop obj = cast_to_oop(obj_addr);
1398 // ctx->is_marked() returns true if mark bit set (TAMS not relevant during init mark)
1399 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1400 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1401 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1402 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1403 obj->oop_iterate(&check_interesting_pointers);
1404 }
1405 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1406 if (!scanner->verify_registration(obj_addr, ctx)) {
1407 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1408 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1409 }
1410 obj_addr += obj->size();
1411 } else {
1412 // This object is not live so we don't verify dirty cards contained therein
1413 assert(tams != nullptr, "If object is not live, ctx and tams should be non-null");
1414 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1415 }
1416 }
1417 } // else, we ignore humongous continuation region
1418 } // else, this is not an OLD region so we ignore it
1419 } // all regions have been processed
1420 }
1421
1422 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1423 shenandoah_assert_safepoint();
1424 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1425
1426 ShenandoahRegionIterator iterator;
1427
1428 while (iterator.has_next()) {
1429 ShenandoahHeapRegion* r = iterator.next();
1430 if (r == nullptr) {
1431 // TODO: Can this really happen?
1432 break;
1433 }
1434 if (r->is_old() && !r->is_cset()) {
1435 help_verify_region_rem_set(r, nullptr, r->bottom(), r->top(), r->top(), "Remembered set violation at end of Full GC");
1436 }
1437 }
1438 }
1439
1440 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1441 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1442 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1443 // all PLABS are retired immediately before the start of update refs.
1444 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1445 shenandoah_assert_safepoint();
1446 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1447
1448 ShenandoahRegionIterator iterator;
1449 ShenandoahMarkingContext* ctx;
1450
1451 if (_heap->old_generation()->is_mark_complete() || _heap->active_generation()->is_global()) {
1452 ctx = _heap->complete_marking_context();
1453 } else {
1454 ctx = nullptr;
1455 }
1456
1457 while (iterator.has_next()) {
1458 ShenandoahHeapRegion* r = iterator.next();
1459 if (r == nullptr) {
1460 // TODO: Can this really happen?
1461 break;
1462 }
1463 if (r->is_old() && !r->is_cset()) {
1464 help_verify_region_rem_set(r, ctx, r->bottom(), r->top(), r->get_update_watermark(),
1465 "Remembered set violation at init-update-references");
1466 }
1467 }
1468 }
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