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()
188 Klass* fwd_klass = fwd->klass_or_null();
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 }
292 * Useful when picking up the object at known offset in heap,
293 * but without knowing what objects reference it.
294 * @param obj verified object
295 */
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);
351 msg.append("%s", ss.as_string());
352
353 report_vm_error(__FILE__, __LINE__, msg.buffer());
354 }
355
356 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
357 if (!test) {
358 print_failure(r, msg);
359 }
360 }
361
362 void heap_region_do(ShenandoahHeapRegion* r) {
363 switch (_regions) {
364 case ShenandoahVerifier::_verify_regions_disable:
365 break;
366 case ShenandoahVerifier::_verify_regions_notrash:
367 verify(r, !r->is_trash(),
368 "Should not have trash regions");
369 break;
370 case ShenandoahVerifier::_verify_regions_nocset:
371 verify(r, !r->is_cset(),
372 "Should not have cset regions");
373 break;
374 case ShenandoahVerifier::_verify_regions_notrash_nocset:
375 verify(r, !r->is_trash(),
376 "Should not have trash regions");
377 verify(r, !r->is_cset(),
378 "Should not have cset regions");
379 break;
380 default:
381 ShouldNotReachHere();
382 }
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,
436 ShenandoahLivenessData* ld,
437 const char* label,
438 ShenandoahVerifier::VerifyOptions options) :
439 WorkerTask("Shenandoah Verifier Reachable Objects"),
440 _label(label),
441 _options(options),
442 _heap(ShenandoahHeap::heap()),
443 _ld(ld),
444 _bitmap(bitmap),
445 _processed(0) {};
446
447 size_t processed() {
448 return _processed;
449 }
450
451 virtual void work(uint worker_id) {
452 ResourceMark rm;
453 ShenandoahVerifierStack stack;
454
455 // On level 2, we need to only check the roots once.
456 // On level 3, we want to check the roots, and seed the local stack.
457 // It is a lesser evil to accept multiple root scans at level 3, because
458 // extended parallelism would buy us out.
459 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
460 || (ShenandoahVerifyLevel >= 3)) {
461 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
462 ShenandoahMessageBuffer("%s, Roots", _label),
463 _options);
464 if (_heap->unload_classes()) {
465 ShenandoahRootVerifier::strong_roots_do(&cl);
466 } else {
467 ShenandoahRootVerifier::roots_do(&cl);
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) {
587 // everything was already marked, and never touching further:
588 if (!is_instance_ref_klass(obj->klass())) {
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->gc_generation();
98 assert(_generation != nullptr, "Expected active generation in this mode");
99 shenandoah_assert_generations_reconciled();
100 }
101 }
102
103 private:
104 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
105 if (!test) {
106 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
107 }
108 }
109
110 template <class T>
111 void do_oop_work(T* p) {
112 T o = RawAccess<>::oop_load(p);
113 if (!CompressedOops::is_null(o)) {
114 oop obj = CompressedOops::decode_not_null(o);
115 if (is_instance_ref_klass(obj->klass())) {
116 obj = ShenandoahForwarding::get_forwardee(obj);
117 }
118 // Single threaded verification can use faster non-atomic stack and bitmap
119 // methods.
120 //
121 // For performance reasons, only fully verify non-marked field values.
122 // We are here when the host object for *p is already marked.
123
124 // TODO: We should consider specializing this closure by generation ==/!= null,
125 // to avoid in_generation check on fast path here for non-generational mode.
126 if (in_generation(obj) && _map->par_mark(obj)) {
127 verify_oop_at(p, obj);
128 _stack->push(ShenandoahVerifierTask(obj));
129 }
130 }
131 }
132
133 bool in_generation(oop obj) {
134 if (_generation == nullptr) {
135 return true;
136 }
137
138 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
139 return _generation->contains(region);
140 }
141
142 void verify_oop(oop obj) {
143 // Perform consistency checks with gradually decreasing safety level. This guarantees
144 // that failure report would not try to touch something that was not yet verified to be
145 // safe to process.
146
147 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
148 "oop must be in heap");
149 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
150 "oop must be aligned");
151
152 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
153 Klass* obj_klass = obj->klass_or_null();
154
155 // Verify that obj is not in dead space:
156 {
157 // Do this before touching obj->size()
158 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
159 "Object klass pointer should not be null");
160 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
161 "Object klass pointer must go to metaspace");
172 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
173 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
174 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
175 "Humongous object is in continuation that fits it");
176 }
177 }
178
179 // ------------ obj is safe at this point --------------
180
181 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
182 "Object should be in active region");
183
184 switch (_options._verify_liveness) {
185 case ShenandoahVerifier::_verify_liveness_disable:
186 // skip
187 break;
188 case ShenandoahVerifier::_verify_liveness_complete:
189 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
190 // fallthrough for fast failure for un-live regions:
191 case ShenandoahVerifier::_verify_liveness_conservative:
192 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
193 (obj_reg->is_old() && _heap->gc_generation()->is_young()),
194 "Object must belong to region with live data");
195 shenandoah_assert_generations_reconciled();
196 break;
197 default:
198 assert(false, "Unhandled liveness verification");
199 }
200 }
201
202 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
203
204 ShenandoahHeapRegion* fwd_reg = nullptr;
205
206 if (obj != fwd) {
207 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
208 "Forwardee must be in heap");
209 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
210 "Forwardee is set");
211 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
212 "Forwardee must be aligned");
213
214 // Do this before touching fwd->size()
215 Klass* fwd_klass = fwd->klass_or_null();
223 fwd_reg = _heap->heap_region_containing(fwd);
224
225 // Verify that forwardee is not in the dead space:
226 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
227 "Should have no humongous forwardees");
228
229 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
230 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
231 "Forwardee start should be within the region");
232 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
233 "Forwardee end should be within the region");
234
235 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
236 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
237 "Double forwarding");
238 } else {
239 fwd_reg = obj_reg;
240 }
241
242 // ------------ obj and fwd are safe at this point --------------
243 // We allow for marked or old here for two reasons:
244 // 1. If this is a young collect, old objects wouldn't be marked. We've
245 // recently change the verifier traversal to only follow young objects
246 // during a young collect so this _shouldn't_ be necessary.
247 // 2. At present, we do not clear dead objects from the remembered set.
248 // Everything in the remembered set is old (ipso facto), so allowing for
249 // 'marked_or_old' covers the case of stale objects in rset.
250 // TODO: Just use 'is_marked' here.
251 switch (_options._verify_marked) {
252 case ShenandoahVerifier::_verify_marked_disable:
253 // skip
254 break;
255 case ShenandoahVerifier::_verify_marked_incomplete:
256 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked_or_old(obj),
257 "Must be marked in incomplete bitmap");
258 break;
259 case ShenandoahVerifier::_verify_marked_complete:
260 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
261 "Must be marked in complete bitmap");
262 break;
263 case ShenandoahVerifier::_verify_marked_complete_except_references:
264 case ShenandoahVerifier::_verify_marked_complete_satb_empty:
265 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
266 "Must be marked in complete bitmap, except j.l.r.Reference referents");
267 break;
268 default:
269 assert(false, "Unhandled mark verification");
270 }
271
272 switch (_options._verify_forwarded) {
273 case ShenandoahVerifier::_verify_forwarded_disable:
274 // skip
275 break;
276 case ShenandoahVerifier::_verify_forwarded_none: {
277 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
278 "Should not be forwarded");
279 break;
280 }
281 case ShenandoahVerifier::_verify_forwarded_allow: {
282 if (obj != fwd) {
283 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
284 "Forwardee should be in another region");
285 }
327 * Useful when picking up the object at known offset in heap,
328 * but without knowing what objects reference it.
329 * @param obj verified object
330 */
331 void verify_oop_standalone(oop obj) {
332 _interior_loc = nullptr;
333 verify_oop(obj);
334 _interior_loc = nullptr;
335 }
336
337 /**
338 * Verify oop fields from this object.
339 * @param obj host object for verified fields
340 */
341 void verify_oops_from(oop obj) {
342 _loc = obj;
343 obj->oop_iterate(this);
344 _loc = nullptr;
345 }
346
347 void do_oop(oop* p) override { do_oop_work(p); }
348 void do_oop(narrowOop* p) override { do_oop_work(p); }
349 };
350
351 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
352 // a subset (e.g. the young generation or old generation) of the total heap.
353 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
354 private:
355 size_t _used, _committed, _garbage, _regions, _humongous_waste;
356 public:
357 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0) {};
358
359 void heap_region_do(ShenandoahHeapRegion* r) override {
360 _used += r->used();
361 _garbage += r->garbage();
362 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
363 if (r->is_humongous()) {
364 _humongous_waste += r->free();
365 }
366 _regions++;
367 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
368 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
369 }
370
371 size_t used() const { return _used; }
372 size_t committed() const { return _committed; }
373 size_t garbage() const { return _garbage; }
374 size_t regions() const { return _regions; }
375 size_t waste() const { return _humongous_waste; }
376
377 // span is the total memory affiliated with these stats (some of which is in use and other is available)
378 size_t span() const { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
379 };
380
381 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
382 public:
383 ShenandoahCalculateRegionStatsClosure old;
384 ShenandoahCalculateRegionStatsClosure young;
385 ShenandoahCalculateRegionStatsClosure global;
386
387 void heap_region_do(ShenandoahHeapRegion* r) override {
388 switch (r->affiliation()) {
389 case FREE:
390 return;
391 case YOUNG_GENERATION:
392 young.heap_region_do(r);
393 global.heap_region_do(r);
394 break;
395 case OLD_GENERATION:
396 old.heap_region_do(r);
397 global.heap_region_do(r);
398 break;
399 default:
400 ShouldNotReachHere();
401 }
402 }
403
404 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
405 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
406 generation->name(),
407 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
408 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
409 }
410
411 static void validate_usage(const bool adjust_for_padding,
412 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
413 ShenandoahHeap* heap = ShenandoahHeap::heap();
414 size_t generation_used = generation->used();
415 size_t generation_used_regions = generation->used_regions();
416 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
417 size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
418 generation_used += pad;
419 }
420
421 guarantee(stats.used() == generation_used,
422 "%s: generation (%s) used size must be consistent: generation-used: " PROPERFMT ", regions-used: " PROPERFMT,
423 label, generation->name(), PROPERFMTARGS(generation_used), PROPERFMTARGS(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 guarantee(stats.span() <= generation_capacity,
431 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") must not exceed current capacity (" PROPERFMT ")",
432 label, generation->name(), stats.regions(), PROPERFMTARGS(generation_capacity));
433
434 size_t humongous_waste = generation->get_humongous_waste();
435 guarantee(stats.waste() == humongous_waste,
436 "%s: generation (%s) humongous waste must be consistent: generation: " PROPERFMT ", regions: " PROPERFMT,
437 label, generation->name(), PROPERFMTARGS(humongous_waste), PROPERFMTARGS(stats.waste()));
438 }
439 };
440
441 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
442 private:
443 ShenandoahHeap* _heap;
444 const char* _phase;
445 ShenandoahVerifier::VerifyRegions _regions;
446 public:
447 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
448 _heap(ShenandoahHeap::heap()),
449 _phase(phase),
450 _regions(regions) {};
451
452 void print_failure(ShenandoahHeapRegion* r, const char* label) {
453 ResourceMark rm;
454
455 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
456
457 stringStream ss;
458 r->print_on(&ss);
459 msg.append("%s", ss.as_string());
460
461 report_vm_error(__FILE__, __LINE__, msg.buffer());
462 }
463
464 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
465 if (!test) {
466 print_failure(r, msg);
467 }
468 }
469
470 void heap_region_do(ShenandoahHeapRegion* r) override {
471 switch (_regions) {
472 case ShenandoahVerifier::_verify_regions_disable:
473 break;
474 case ShenandoahVerifier::_verify_regions_notrash:
475 verify(r, !r->is_trash(),
476 "Should not have trash regions");
477 break;
478 case ShenandoahVerifier::_verify_regions_nocset:
479 verify(r, !r->is_cset(),
480 "Should not have cset regions");
481 break;
482 case ShenandoahVerifier::_verify_regions_notrash_nocset:
483 verify(r, !r->is_trash(),
484 "Should not have trash regions");
485 verify(r, !r->is_cset(),
486 "Should not have cset regions");
487 break;
488 default:
489 ShouldNotReachHere();
490 }
502 "Complete TAMS should not be larger than top");
503
504 verify(r, r->get_live_data_bytes() <= r->capacity(),
505 "Live data cannot be larger than capacity");
506
507 verify(r, r->garbage() <= r->capacity(),
508 "Garbage cannot be larger than capacity");
509
510 verify(r, r->used() <= r->capacity(),
511 "Used cannot be larger than capacity");
512
513 verify(r, r->get_shared_allocs() <= r->capacity(),
514 "Shared alloc count should not be larger than capacity");
515
516 verify(r, r->get_tlab_allocs() <= r->capacity(),
517 "TLAB alloc count should not be larger than capacity");
518
519 verify(r, r->get_gclab_allocs() <= r->capacity(),
520 "GCLAB alloc count should not be larger than capacity");
521
522 verify(r, r->get_plab_allocs() <= r->capacity(),
523 "PLAB alloc count should not be larger than capacity");
524
525 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
526 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
527
528 verify(r, !r->is_empty() || !r->has_live(),
529 "Empty regions should not have live data");
530
531 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
532 "Transitional: region flags and collection set agree");
533 }
534 };
535
536 class ShenandoahVerifierReachableTask : public WorkerTask {
537 private:
538 const char* _label;
539 ShenandoahVerifier::VerifyOptions _options;
540 ShenandoahHeap* _heap;
541 ShenandoahLivenessData* _ld;
542 MarkBitMap* _bitmap;
543 volatile size_t _processed;
544
545 public:
546 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
547 ShenandoahLivenessData* ld,
548 const char* label,
549 ShenandoahVerifier::VerifyOptions options) :
550 WorkerTask("Shenandoah Verifier Reachable Objects"),
551 _label(label),
552 _options(options),
553 _heap(ShenandoahHeap::heap()),
554 _ld(ld),
555 _bitmap(bitmap),
556 _processed(0) {};
557
558 size_t processed() const {
559 return _processed;
560 }
561
562 void work(uint worker_id) override {
563 ResourceMark rm;
564 ShenandoahVerifierStack stack;
565
566 // On level 2, we need to only check the roots once.
567 // On level 3, we want to check the roots, and seed the local stack.
568 // It is a lesser evil to accept multiple root scans at level 3, because
569 // extended parallelism would buy us out.
570 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
571 || (ShenandoahVerifyLevel >= 3)) {
572 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
573 ShenandoahMessageBuffer("%s, Roots", _label),
574 _options);
575 if (_heap->unload_classes()) {
576 ShenandoahRootVerifier::strong_roots_do(&cl);
577 } else {
578 ShenandoahRootVerifier::roots_do(&cl);
579 }
580 }
581
582 size_t processed = 0;
583
584 if (ShenandoahVerifyLevel >= 3) {
585 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
586 ShenandoahMessageBuffer("%s, Reachable", _label),
587 _options);
588 while (!stack.is_empty()) {
589 processed++;
590 ShenandoahVerifierTask task = stack.pop();
591 cl.verify_oops_from(task.obj());
592 }
593 }
594
595 Atomic::add(&_processed, processed, memory_order_relaxed);
596 }
597 };
598
599 class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
600 public:
601 void do_thread(Thread* thread) override {
602 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
603 if (!is_empty(queue)) {
604 fatal("All SATB buffers should have been flushed during mark");
605 }
606 }
607 private:
608 bool is_empty(SATBMarkQueue& queue) {
609 return queue.buffer() == nullptr || queue.index() == queue.capacity();
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->gc_generation();
644 assert(_generation != nullptr, "Expected active generation in this mode.");
645 shenandoah_assert_generations_reconciled();
646 }
647 };
648
649 size_t processed() {
650 return Atomic::load(&_processed);
651 }
652
653 void work(uint worker_id) override {
654 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
655 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
656 Threads::possibly_parallel_threads_do(true, &verify_satb);
657 }
658
659 ShenandoahVerifierStack stack;
660 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
661 ShenandoahMessageBuffer("%s, Marked", _label),
662 _options);
663
664 while (true) {
665 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
666 if (v < _heap->num_regions()) {
667 ShenandoahHeapRegion* r = _heap->get_region(v);
668 if (!in_generation(r)) {
669 continue;
670 }
671
672 if (!r->is_humongous() && !r->is_trash()) {
673 work_regular(r, stack, cl);
674 } else if (r->is_humongous_start()) {
675 work_humongous(r, stack, cl);
676 }
677 } else {
678 break;
679 }
680 }
681 }
682
683 bool in_generation(ShenandoahHeapRegion* r) {
684 return _generation == nullptr || _generation->contains(r);
685 }
686
687 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
688 size_t processed = 0;
689 HeapWord* obj = r->bottom();
690 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
691 verify_and_follow(obj, stack, cl, &processed);
692 }
693 Atomic::add(&_processed, processed, memory_order_relaxed);
694 }
695
696 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
697 size_t processed = 0;
698 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
699 HeapWord* tams = ctx->top_at_mark_start(r);
700
701 // Bitmaps, before TAMS
702 if (tams > r->bottom()) {
703 HeapWord* start = r->bottom();
704 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
705
706 while (addr < tams) {
737 // everything was already marked, and never touching further:
738 if (!is_instance_ref_klass(obj->klass())) {
739 cl.verify_oops_from(obj);
740 (*processed)++;
741 }
742 while (!stack.is_empty()) {
743 ShenandoahVerifierTask task = stack.pop();
744 cl.verify_oops_from(task.obj());
745 (*processed)++;
746 }
747 }
748 };
749
750 class VerifyThreadGCState : public ThreadClosure {
751 private:
752 const char* const _label;
753 char const _expected;
754
755 public:
756 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
757 void do_thread(Thread* t) override {
758 char actual = ShenandoahThreadLocalData::gc_state(t);
759 if (!verify_gc_state(actual, _expected)) {
760 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
761 }
762 }
763
764 static bool verify_gc_state(char actual, char expected) {
765 // Old generation marking is allowed in all states.
766 if (ShenandoahHeap::heap()->mode()->is_generational()) {
767 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
768 } else {
769 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
770 return (actual == expected);
771 }
772 }
773 };
774
775 void ShenandoahVerifier::verify_at_safepoint(const char* label,
776 VerifyRememberedSet remembered,
777 VerifyForwarded forwarded, VerifyMarked marked,
778 VerifyCollectionSet cset,
779 VerifyLiveness liveness, VerifyRegions regions,
780 VerifySize sizeness,
781 VerifyGCState gcstate) {
782 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
783 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
784
785 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
786
787 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
788 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
789
790 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
791
792 // GC state checks
793 {
794 char expected = -1;
795 bool enabled;
796 switch (gcstate) {
797 case _verify_gcstate_disable:
798 enabled = false;
799 break;
800 case _verify_gcstate_forwarded:
801 enabled = true;
802 expected = ShenandoahHeap::HAS_FORWARDED;
803 break;
804 case _verify_gcstate_evacuation:
805 enabled = true;
806 expected = ShenandoahHeap::EVACUATION;
807 if (!_heap->is_stw_gc_in_progress()) {
808 // Only concurrent GC sets this.
809 expected |= ShenandoahHeap::WEAK_ROOTS;
810 }
811 break;
812 case _verify_gcstate_updating:
813 enabled = true;
814 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
815 break;
816 case _verify_gcstate_stable:
817 enabled = true;
818 expected = ShenandoahHeap::STABLE;
819 break;
820 case _verify_gcstate_stable_weakroots:
821 enabled = true;
822 expected = ShenandoahHeap::STABLE;
823 if (!_heap->is_stw_gc_in_progress()) {
824 // Only concurrent GC sets this.
825 expected |= ShenandoahHeap::WEAK_ROOTS;
826 }
827 break;
828 default:
829 enabled = false;
830 assert(false, "Unhandled gc-state verification");
831 }
832
833 if (enabled) {
834 char actual = _heap->gc_state();
835
836 bool is_marking = (actual & ShenandoahHeap::MARKING);
837 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
838 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
839
840 // Old generation marking is allowed in all states.
841 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
842 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
843 }
844
845 VerifyThreadGCState vtgcs(label, expected);
846 Threads::java_threads_do(&vtgcs);
847 }
848 }
849
850 // Deactivate barriers temporarily: Verifier wants plain heap accesses
851 ShenandoahGCStateResetter resetter;
852
853 // Heap size checks
854 {
855 ShenandoahHeapLocker lock(_heap->lock());
856
857 ShenandoahCalculateRegionStatsClosure cl;
858 _heap->heap_region_iterate(&cl);
859 size_t heap_used;
860 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
861 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
862 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
863 } else if (sizeness != _verify_size_disable) {
864 heap_used = _heap->used();
865 }
866 if (sizeness != _verify_size_disable) {
867 guarantee(cl.used() == heap_used,
868 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
869 label,
870 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
871 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
872 }
873 size_t heap_committed = _heap->committed();
874 guarantee(cl.committed() == heap_committed,
875 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
876 label,
877 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
878 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
879 }
880
881 log_debug(gc)("Safepoint verification finished heap usage verification");
882
883 ShenandoahGeneration* generation;
884 if (_heap->mode()->is_generational()) {
885 generation = _heap->gc_generation();
886 guarantee(generation != nullptr, "Need to know which generation to verify.");
887 shenandoah_assert_generations_reconciled();
888 } else {
889 generation = nullptr;
890 }
891
892 if (generation != nullptr) {
893 ShenandoahHeapLocker lock(_heap->lock());
894
895 switch (remembered) {
896 case _verify_remembered_disable:
897 break;
898 case _verify_remembered_before_marking:
899 log_debug(gc)("Safepoint verification of remembered set at mark");
900 verify_rem_set_before_mark();
901 break;
902 case _verify_remembered_before_updating_references:
903 log_debug(gc)("Safepoint verification of remembered set at update ref");
904 verify_rem_set_before_update_ref();
905 break;
906 case _verify_remembered_after_full_gc:
907 log_debug(gc)("Safepoint verification of remembered set after full gc");
908 verify_rem_set_after_full_gc();
909 break;
910 default:
911 fatal("Unhandled remembered set verification mode");
912 }
913
914 ShenandoahGenerationStatsClosure cl;
915 _heap->heap_region_iterate(&cl);
916
917 if (LogTarget(Debug, gc)::is_enabled()) {
918 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
919 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
920 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
921 }
922 if (sizeness == _verify_size_adjusted_for_padding) {
923 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
924 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
925 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
926 } else if (sizeness == _verify_size_exact) {
927 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
928 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
929 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
930 }
931 // else: sizeness must equal _verify_size_disable
932 }
933
934 log_debug(gc)("Safepoint verification finished remembered set verification");
935
936 // Internal heap region checks
937 if (ShenandoahVerifyLevel >= 1) {
938 ShenandoahVerifyHeapRegionClosure cl(label, regions);
939 if (generation != nullptr) {
940 generation->heap_region_iterate(&cl);
941 } else {
942 _heap->heap_region_iterate(&cl);
943 }
944 }
945
946 log_debug(gc)("Safepoint verification finished heap region closure verification");
947
948 OrderAccess::fence();
949
950 if (UseTLAB) {
951 _heap->labs_make_parsable();
952 }
953
954 // Allocate temporary bitmap for storing marking wavefront:
955 _verification_bit_map->clear();
956
957 // Allocate temporary array for storing liveness data
958 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
959 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
960
961 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
962
963 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
964 // This verifies what application can see, since it only cares about reachable objects.
965 size_t count_reachable = 0;
966 if (ShenandoahVerifyLevel >= 2) {
967 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
968 _heap->workers()->run_task(&task);
969 count_reachable = task.processed();
970 }
971
972 log_debug(gc)("Safepoint verification finished getting initial reachable set");
973
974 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
975 // not the application, can see during the region scans. There is no reason to process the objects
976 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
977 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
978 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
979 // version
980
981 size_t count_marked = 0;
982 if (ShenandoahVerifyLevel >= 4 &&
983 (marked == _verify_marked_complete ||
984 marked == _verify_marked_complete_except_references ||
985 marked == _verify_marked_complete_satb_empty)) {
986 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
987 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
988 _heap->workers()->run_task(&task);
989 count_marked = task.processed();
990 } else {
991 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
992 }
993
994 log_debug(gc)("Safepoint verification finished walking marked objects");
995
996 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
997 // marked objects.
998
999 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
1000 for (size_t i = 0; i < _heap->num_regions(); i++) {
1001 ShenandoahHeapRegion* r = _heap->get_region(i);
1002 if (generation != nullptr && !generation->contains(r)) {
1003 continue;
1004 }
1005
1006 juint verf_live = 0;
1007 if (r->is_humongous()) {
1008 // For humongous objects, test if start region is marked live, and if so,
1009 // all humongous regions in that chain have live data equal to their "used".
1010 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1011 if (start_live > 0) {
1012 verf_live = (juint)(r->used() / HeapWordSize);
1013 }
1014 } else {
1015 verf_live = Atomic::load(&ld[r->index()]);
1016 }
1017
1018 size_t reg_live = r->get_live_data_words();
1019 if (reg_live != verf_live) {
1020 stringStream ss;
1021 r->print_on(&ss);
1022 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
1023 label, reg_live, verf_live, ss.freeze());
1024 }
1025 }
1026 }
1027
1028 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1029
1030
1031 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
1032 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1033
1034 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1035 }
1036
1037 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1038 verify_at_safepoint(
1039 "Generic Verification",
1040 _verify_remembered_disable, // do not verify remembered set
1041 _verify_forwarded_allow, // conservatively allow forwarded
1042 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1043 _verify_cset_disable, // cset may be inconsistent
1044 _verify_liveness_disable, // no reliable liveness data
1045 _verify_regions_disable, // no reliable region data
1046 _verify_size_exact, // expect generation and heap sizes to match exactly
1047 _verify_gcstate_disable // no data about gcstate
1048 );
1049 }
1050
1051 void ShenandoahVerifier::verify_before_concmark() {
1052 verify_at_safepoint(
1053 "Before Mark",
1054 _verify_remembered_before_marking,
1055 // verify read-only remembered set from bottom() to top()
1056 _verify_forwarded_none, // UR should have fixed up
1057 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1058 _verify_cset_none, // UR should have fixed this
1059 _verify_liveness_disable, // no reliable liveness data
1060 _verify_regions_notrash, // no trash regions
1061 _verify_size_exact, // expect generation and heap sizes to match exactly
1062 _verify_gcstate_stable // there are no forwarded objects
1063 );
1064 }
1065
1066 void ShenandoahVerifier::verify_after_concmark() {
1067 verify_at_safepoint(
1068 "After Mark",
1069 _verify_remembered_disable, // do not verify remembered set
1070 _verify_forwarded_none, // no forwarded references
1071 _verify_marked_complete_satb_empty,
1072 // bitmaps as precise as we can get, except dangling j.l.r.Refs
1073 _verify_cset_none, // no references to cset anymore
1074 _verify_liveness_complete, // liveness data must be complete here
1075 _verify_regions_disable, // trash regions not yet recycled
1076 _verify_size_exact, // expect generation and heap sizes to match exactly
1077 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1078 );
1079 }
1080
1081 void ShenandoahVerifier::verify_before_evacuation() {
1082 verify_at_safepoint(
1083 "Before Evacuation",
1084 _verify_remembered_disable, // do not verify remembered set
1085 _verify_forwarded_none, // no forwarded references
1086 _verify_marked_complete_except_references, // walk over marked objects too
1087 _verify_cset_disable, // non-forwarded references to cset expected
1088 _verify_liveness_complete, // liveness data must be complete here
1089 _verify_regions_disable, // trash regions not yet recycled
1090 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1091 // for promote in place padding
1092 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1093 );
1094 }
1095
1096 void ShenandoahVerifier::verify_during_evacuation() {
1097 verify_at_safepoint(
1098 "During Evacuation",
1099 _verify_remembered_disable, // do not verify remembered set
1100 _verify_forwarded_allow, // some forwarded references are allowed
1101 _verify_marked_disable, // walk only roots
1102 _verify_cset_disable, // some cset references are not forwarded yet
1103 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1104 _verify_regions_disable, // trash regions not yet recycled
1105 _verify_size_disable, // we don't know how much of promote-in-place work has been completed
1106 _verify_gcstate_evacuation // evacuation is in progress
1107 );
1108 }
1109
1110 void ShenandoahVerifier::verify_after_evacuation() {
1111 verify_at_safepoint(
1112 "After Evacuation",
1113 _verify_remembered_disable, // do not verify remembered set
1114 _verify_forwarded_allow, // objects are still forwarded
1115 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1116 _verify_cset_forwarded, // all cset refs are fully forwarded
1117 _verify_liveness_disable, // no reliable liveness data anymore
1118 _verify_regions_notrash, // trash regions have been recycled already
1119 _verify_size_exact, // expect generation and heap sizes to match exactly
1120 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1121 );
1122 }
1123
1124 void ShenandoahVerifier::verify_before_updaterefs() {
1125 verify_at_safepoint(
1126 "Before Updating References",
1127 _verify_remembered_before_updating_references, // verify read-write remembered set
1128 _verify_forwarded_allow, // forwarded references allowed
1129 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1130 _verify_cset_forwarded, // all cset refs are fully forwarded
1131 _verify_liveness_disable, // no reliable liveness data anymore
1132 _verify_regions_notrash, // trash regions have been recycled already
1133 _verify_size_exact, // expect generation and heap sizes to match exactly
1134 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1135 );
1136 }
1137
1138 // We have not yet cleanup (reclaimed) the collection set
1139 void ShenandoahVerifier::verify_after_updaterefs() {
1140 verify_at_safepoint(
1141 "After Updating References",
1142 _verify_remembered_disable, // do not verify remembered set
1143 _verify_forwarded_none, // no forwarded references
1144 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1145 _verify_cset_none, // no cset references, all updated
1146 _verify_liveness_disable, // no reliable liveness data anymore
1147 _verify_regions_nocset, // no cset regions, trash regions have appeared
1148 _verify_size_exact, // expect generation and heap sizes to match exactly
1149 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1150 );
1151 }
1152
1153 void ShenandoahVerifier::verify_after_degenerated() {
1154 verify_at_safepoint(
1155 "After Degenerated GC",
1156 _verify_remembered_disable, // do not verify remembered set
1157 _verify_forwarded_none, // all objects are non-forwarded
1158 _verify_marked_complete, // all objects are marked in complete bitmap
1159 _verify_cset_none, // no cset references
1160 _verify_liveness_disable, // no reliable liveness data anymore
1161 _verify_regions_notrash_nocset, // no trash, no cset
1162 _verify_size_exact, // expect generation and heap sizes to match exactly
1163 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1164 );
1165 }
1166
1167 void ShenandoahVerifier::verify_before_fullgc() {
1168 verify_at_safepoint(
1169 "Before Full GC",
1170 _verify_remembered_disable, // do not verify remembered set
1171 _verify_forwarded_allow, // can have forwarded objects
1172 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1173 _verify_cset_disable, // cset might be foobared
1174 _verify_liveness_disable, // no reliable liveness data anymore
1175 _verify_regions_disable, // no reliable region data here
1176 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1177 _verify_gcstate_disable // no reliable gcstate data
1178 );
1179 }
1180
1181 void ShenandoahVerifier::verify_after_fullgc() {
1182 verify_at_safepoint(
1183 "After Full GC",
1184 _verify_remembered_after_full_gc, // verify read-write remembered set
1185 _verify_forwarded_none, // all objects are non-forwarded
1186 _verify_marked_complete, // all objects are marked in complete bitmap
1187 _verify_cset_none, // no cset references
1188 _verify_liveness_disable, // no reliable liveness data anymore
1189 _verify_regions_notrash_nocset, // no trash, no cset
1190 _verify_size_exact, // expect generation and heap sizes to match exactly
1191 _verify_gcstate_stable // full gc cleaned up everything
1192 );
1193 }
1194
1195 // TODO: Why this closure does not visit metadata?
1196 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1197 private:
1198 template <class T>
1199 void do_oop_work(T* p) {
1200 T o = RawAccess<>::oop_load(p);
1201 if (!CompressedOops::is_null(o)) {
1202 oop obj = CompressedOops::decode_not_null(o);
1203 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1204 if (obj != fwd) {
1205 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1206 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1207 }
1208 }
1209 }
1210
1211 public:
1212 void do_oop(narrowOop* p) { do_oop_work(p); }
1213 void do_oop(oop* p) { do_oop_work(p); }
1214 };
1215
1216 // TODO: Why this closure does not visit metadata?
1217 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1218 private:
1219 template <class T>
1220 void do_oop_work(T* p) {
1221 T o = RawAccess<>::oop_load(p);
1222 if (!CompressedOops::is_null(o)) {
1223 oop obj = CompressedOops::decode_not_null(o);
1224 ShenandoahHeap* heap = ShenandoahHeap::heap();
1225
1226 if (!heap->marking_context()->is_marked_or_old(obj)) {
1227 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1228 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1229 }
1230
1231 if (heap->in_collection_set(obj)) {
1232 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1233 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1234 }
1235
1236 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1237 if (obj != fwd) {
1238 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1239 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1240 }
1241 }
1242 }
1243
1244 public:
1245 void do_oop(narrowOop* p) override { do_oop_work(p); }
1246 void do_oop(oop* p) override { do_oop_work(p); }
1247 };
1248
1249 void ShenandoahVerifier::verify_roots_in_to_space() {
1250 ShenandoahVerifyInToSpaceClosure cl;
1251 ShenandoahRootVerifier::roots_do(&cl);
1252 }
1253
1254 void ShenandoahVerifier::verify_roots_no_forwarded() {
1255 ShenandoahVerifyNoForwared cl;
1256 ShenandoahRootVerifier::roots_do(&cl);
1257 }
1258
1259 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1260 protected:
1261 bool const _init_mark;
1262 ShenandoahGenerationalHeap* const _heap;
1263 RememberedScanner* const _scanner;
1264
1265 public:
1266 // Argument distinguishes between initial mark or start of update refs verification.
1267 explicit ShenandoahVerifyRemSetClosure(bool init_mark) :
1268 _init_mark(init_mark),
1269 _heap(ShenandoahGenerationalHeap::heap()),
1270 _scanner(_heap->old_generation()->card_scan()) {}
1271
1272 template<class T>
1273 inline void work(T* p) {
1274 T o = RawAccess<>::oop_load(p);
1275 if (!CompressedOops::is_null(o)) {
1276 oop obj = CompressedOops::decode_not_null(o);
1277 if (_heap->is_in_young(obj)) {
1278 size_t card_index = _scanner->card_index_for_addr((HeapWord*) p);
1279 if (_init_mark && !_scanner->is_card_dirty(card_index)) {
1280 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1281 "Verify init-mark remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1282 } else if (!_init_mark && !_scanner->is_write_card_dirty(card_index)) {
1283 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1284 "Verify init-update-refs remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1285 }
1286 }
1287 }
1288 }
1289
1290 void do_oop(narrowOop* p) override { work(p); }
1291 void do_oop(oop* p) override { work(p); }
1292 };
1293
1294 void ShenandoahVerifier::help_verify_region_rem_set(ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx, HeapWord* from,
1295 HeapWord* top, HeapWord* registration_watermark, const char* message) {
1296 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1297 ShenandoahVerifyRemSetClosure check_interesting_pointers(false);
1298
1299 HeapWord* obj_addr = from;
1300 if (r->is_humongous_start()) {
1301 oop obj = cast_to_oop(obj_addr);
1302 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1303 size_t card_index = scanner->card_index_for_addr(obj_addr);
1304 // For humongous objects, the typical object is an array, so the following checks may be overkill
1305 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1306 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1307 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1308 obj->oop_iterate(&check_interesting_pointers);
1309 }
1310 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1311 }
1312 // else, this humongous object is not live so no need to verify its internal pointers
1313
1314 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1315 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1316 "object not properly registered", __FILE__, __LINE__);
1317 }
1318 } else if (!r->is_humongous()) {
1319 while (obj_addr < top) {
1320 oop obj = cast_to_oop(obj_addr);
1321 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1322 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1323 size_t card_index = scanner->card_index_for_addr(obj_addr);
1324 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1325 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1326 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1327 obj->oop_iterate(&check_interesting_pointers);
1328 }
1329 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1330
1331 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1332 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1333 "object not properly registered", __FILE__, __LINE__);
1334 }
1335 obj_addr += obj->size();
1336 } else {
1337 // This object is not live so we don't verify dirty cards contained therein
1338 HeapWord* tams = ctx->top_at_mark_start(r);
1339 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1340 }
1341 }
1342 }
1343 }
1344
1345 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1346 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1347 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1348 // restore them until the start of evacuation.
1349 void ShenandoahVerifier::verify_rem_set_before_mark() {
1350 shenandoah_assert_safepoint();
1351 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1352
1353 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1354 ShenandoahVerifyRemSetClosure check_interesting_pointers(true);
1355 ShenandoahMarkingContext* ctx;
1356
1357 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1358 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1359
1360 shenandoah_assert_generations_reconciled();
1361 if (old_generation->is_mark_complete() || _heap->gc_generation()->is_global()) {
1362 ctx = _heap->complete_marking_context();
1363 } else {
1364 ctx = nullptr;
1365 }
1366
1367 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1368 ShenandoahHeapRegion* r = _heap->get_region(i);
1369 HeapWord* tams = (ctx != nullptr) ? ctx->top_at_mark_start(r) : nullptr;
1370
1371 // TODO: Is this replaceable with call to help_verify_region_rem_set?
1372
1373 if (r->is_old() && r->is_active()) {
1374 HeapWord* obj_addr = r->bottom();
1375 if (r->is_humongous_start()) {
1376 oop obj = cast_to_oop(obj_addr);
1377 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1378 // For humongous objects, the typical object is an array, so the following checks may be overkill
1379 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1380 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1381 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1382 obj->oop_iterate(&check_interesting_pointers);
1383 }
1384 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1385 }
1386 // else, this humongous object is not marked so no need to verify its internal pointers
1387 if (!scanner->verify_registration(obj_addr, ctx)) {
1388 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1389 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1390 }
1391 } else if (!r->is_humongous()) {
1392 HeapWord* top = r->top();
1393 while (obj_addr < top) {
1394 oop obj = cast_to_oop(obj_addr);
1395 // ctx->is_marked() returns true if mark bit set (TAMS not relevant during init mark)
1396 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1397 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1398 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1399 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1400 obj->oop_iterate(&check_interesting_pointers);
1401 }
1402 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1403 if (!scanner->verify_registration(obj_addr, ctx)) {
1404 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1405 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1406 }
1407 obj_addr += obj->size();
1408 } else {
1409 // This object is not live so we don't verify dirty cards contained therein
1410 assert(tams != nullptr, "If object is not live, ctx and tams should be non-null");
1411 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1412 }
1413 }
1414 } // else, we ignore humongous continuation region
1415 } // else, this is not an OLD region so we ignore it
1416 } // all regions have been processed
1417 }
1418
1419 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1420 shenandoah_assert_safepoint();
1421 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1422
1423 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1424 ShenandoahHeapRegion* r = _heap->get_region(i);
1425 if (r->is_old() && !r->is_cset()) {
1426 help_verify_region_rem_set(r, nullptr, r->bottom(), r->top(), r->top(), "Remembered set violation at end of Full GC");
1427 }
1428 }
1429 }
1430
1431 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1432 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1433 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1434 // all PLABS are retired immediately before the start of update refs.
1435 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1436 shenandoah_assert_safepoint();
1437 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1438
1439 ShenandoahMarkingContext* ctx;
1440
1441 shenandoah_assert_generations_reconciled();
1442 if (_heap->old_generation()->is_mark_complete() || _heap->gc_generation()->is_global()) {
1443 ctx = _heap->complete_marking_context();
1444 } else {
1445 ctx = nullptr;
1446 }
1447
1448 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1449 ShenandoahHeapRegion* r = _heap->get_region(i);
1450 if (r->is_old() && !r->is_cset()) {
1451 help_verify_region_rem_set(r, ctx, r->bottom(), r->top(), r->get_update_watermark(),
1452 "Remembered set violation at init-update-references");
1453 }
1454 }
1455 }
1456
1457 void ShenandoahVerifier::verify_before_rebuilding_free_set() {
1458 ShenandoahGenerationStatsClosure cl;
1459 _heap->heap_region_iterate(&cl);
1460
1461 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
1462 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
1463 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
1464 }
|