1 /*
2 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25
26 #include "gc/shenandoah/shenandoahAsserts.hpp"
27 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
28 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
31 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
32 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
33 #include "gc/shenandoah/shenandoahUtils.hpp"
34 #include "gc/shenandoah/shenandoahVerifier.hpp"
35 #include "memory/allocation.hpp"
36 #include "memory/iterator.inline.hpp"
37 #include "memory/resourceArea.hpp"
38
39 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
40 #ifdef verify_oop
41 #undef verify_oop
42 #endif
43
44 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
45 private:
46 const char* _phase;
47 ShenandoahVerifier::VerifyOptions _options;
48 ShenandoahVerifierStack* _stack;
49 ShenandoahHeap* _heap;
50 MarkBitMap* _map;
51 ShenandoahLivenessData* _ld;
52 void* _interior_loc;
53 oop _loc;
54
55 public:
56 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
57 const char* phase, ShenandoahVerifier::VerifyOptions options) :
58 _phase(phase),
59 _options(options),
60 _stack(stack),
61 _heap(ShenandoahHeap::heap()),
62 _map(map),
63 _ld(ld),
64 _interior_loc(NULL),
65 _loc(NULL) { }
66
67 private:
68 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
69 if (!test) {
70 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
71 }
72 }
73
74 template <class T>
75 void do_oop_work(T* p) {
76 T o = RawAccess<>::oop_load(p);
77 if (!CompressedOops::is_null(o)) {
78 oop obj = CompressedOops::decode_not_null(o);
79
80 // Single threaded verification can use faster non-atomic stack and bitmap
81 // methods.
82 //
83 // For performance reasons, only fully verify non-marked field values.
84 // We are here when the host object for *p is already marked.
85
86 HeapWord* addr = (HeapWord*) obj;
87 if (_map->parMark(addr)) {
88 verify_oop_at(p, obj);
89 _stack->push(ShenandoahVerifierTask(obj));
90 }
91 }
92 }
93
94 void verify_oop(oop obj) {
95 // Perform consistency checks with gradually decreasing safety level. This guarantees
96 // that failure report would not try to touch something that was not yet verified to be
97 // safe to process.
98
99 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
100 "oop must be in heap");
101 check(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),
102 "oop must be aligned");
103
104 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
105 Klass* obj_klass = obj->klass_or_null();
106
107 // Verify that obj is not in dead space:
108 {
109 // Do this before touching obj->size()
110 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
111 "Object klass pointer should not be NULL");
112 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
113 "Object klass pointer must go to metaspace");
114
115 HeapWord *obj_addr = (HeapWord *) obj;
116 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
117 "Object start should be within the region");
118
119 if (!obj_reg->is_humongous()) {
120 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
121 "Object end should be within the region");
122 } else {
123 size_t humongous_start = obj_reg->index();
124 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
125 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
126 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
127 "Humongous object is in continuation that fits it");
128 }
129 }
130
131 // ------------ obj is safe at this point --------------
132
133 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
134 "Object should be in active region");
135
136 switch (_options._verify_liveness) {
137 case ShenandoahVerifier::_verify_liveness_disable:
138 // skip
139 break;
140 case ShenandoahVerifier::_verify_liveness_complete:
141 Atomic::add((uint) obj->size(), &_ld[obj_reg->index()]);
142 // fallthrough for fast failure for un-live regions:
143 case ShenandoahVerifier::_verify_liveness_conservative:
144 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
145 "Object must belong to region with live data");
146 break;
147 default:
148 assert(false, "Unhandled liveness verification");
149 }
150 }
151
152 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
153
154 ShenandoahHeapRegion* fwd_reg = NULL;
155
156 if (obj != fwd) {
157 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
158 "Forwardee must be in heap");
159 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
160 "Forwardee is set");
161 check(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),
162 "Forwardee must be aligned");
163
164 // Do this before touching fwd->size()
165 Klass* fwd_klass = fwd->klass_or_null();
166 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
167 "Forwardee klass pointer should not be NULL");
168 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
169 "Forwardee klass pointer must go to metaspace");
170 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
171 "Forwardee klass pointer must go to metaspace");
172
173 fwd_reg = _heap->heap_region_containing(fwd);
174
175 // Verify that forwardee is not in the dead space:
176 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
177 "Should have no humongous forwardees");
178
179 HeapWord *fwd_addr = (HeapWord *) fwd;
180 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
181 "Forwardee start should be within the region");
182 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
183 "Forwardee end should be within the region");
184
185 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
186 check(ShenandoahAsserts::_safe_oop, obj, fwd == fwd2,
187 "Double forwarding");
188 } else {
189 fwd_reg = obj_reg;
190 }
191
192 // ------------ obj and fwd are safe at this point --------------
193
194 switch (_options._verify_marked) {
195 case ShenandoahVerifier::_verify_marked_disable:
196 // skip
197 break;
198 case ShenandoahVerifier::_verify_marked_incomplete:
199 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
200 "Must be marked in incomplete bitmap");
201 break;
202 case ShenandoahVerifier::_verify_marked_complete:
203 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
204 "Must be marked in complete bitmap");
205 break;
206 default:
207 assert(false, "Unhandled mark verification");
208 }
209
210 switch (_options._verify_forwarded) {
211 case ShenandoahVerifier::_verify_forwarded_disable:
212 // skip
213 break;
214 case ShenandoahVerifier::_verify_forwarded_none: {
215 check(ShenandoahAsserts::_safe_all, obj, obj == fwd,
216 "Should not be forwarded");
217 break;
218 }
219 case ShenandoahVerifier::_verify_forwarded_allow: {
220 if (obj != fwd) {
221 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
222 "Forwardee should be in another region");
223 }
224 break;
225 }
226 default:
227 assert(false, "Unhandled forwarding verification");
228 }
229
230 switch (_options._verify_cset) {
231 case ShenandoahVerifier::_verify_cset_disable:
232 // skip
233 break;
234 case ShenandoahVerifier::_verify_cset_none:
235 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
236 "Should not have references to collection set");
237 break;
238 case ShenandoahVerifier::_verify_cset_forwarded:
239 if (_heap->in_collection_set(obj)) {
240 check(ShenandoahAsserts::_safe_all, obj, obj != fwd,
241 "Object in collection set, should have forwardee");
242 }
243 break;
244 default:
245 assert(false, "Unhandled cset verification");
246 }
247
248 }
249
250 public:
251 /**
252 * Verify object with known interior reference.
253 * @param p interior reference where the object is referenced from; can be off-heap
254 * @param obj verified object
255 */
256 template <class T>
257 void verify_oop_at(T* p, oop obj) {
258 _interior_loc = p;
259 verify_oop(obj);
260 _interior_loc = NULL;
261 }
262
263 /**
264 * Verify object without known interior reference.
265 * Useful when picking up the object at known offset in heap,
266 * but without knowing what objects reference it.
267 * @param obj verified object
268 */
269 void verify_oop_standalone(oop obj) {
270 _interior_loc = NULL;
271 verify_oop(obj);
272 _interior_loc = NULL;
273 }
274
275 /**
276 * Verify oop fields from this object.
277 * @param obj host object for verified fields
278 */
279 void verify_oops_from(oop obj) {
280 _loc = obj;
281 obj->oop_iterate(this);
282 _loc = NULL;
283 }
284
285 virtual void do_oop(oop* p) { do_oop_work(p); }
286 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
287 };
288
289 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
290 private:
291 size_t _used, _committed, _garbage;
292 public:
293 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
294
295 void heap_region_do(ShenandoahHeapRegion* r) {
296 _used += r->used();
297 _garbage += r->garbage();
298 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
299 }
300
301 size_t used() { return _used; }
302 size_t committed() { return _committed; }
303 size_t garbage() { return _garbage; }
304 };
305
306 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
307 private:
308 ShenandoahHeap* _heap;
309 const char* _phase;
310 ShenandoahVerifier::VerifyRegions _regions;
311 public:
312 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
313 _heap(ShenandoahHeap::heap()),
314 _phase(phase),
315 _regions(regions) {};
316
317 void print_failure(ShenandoahHeapRegion* r, const char* label) {
318 ResourceMark rm;
319
320 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
321
322 stringStream ss;
323 r->print_on(&ss);
324 msg.append("%s", ss.as_string());
325
326 report_vm_error(__FILE__, __LINE__, msg.buffer());
327 }
328
329 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
330 if (!test) {
331 print_failure(r, msg);
332 }
333 }
334
335 void heap_region_do(ShenandoahHeapRegion* r) {
336 switch (_regions) {
337 case ShenandoahVerifier::_verify_regions_disable:
338 break;
339 case ShenandoahVerifier::_verify_regions_notrash:
340 verify(r, !r->is_trash(),
341 "Should not have trash regions");
342 break;
343 case ShenandoahVerifier::_verify_regions_nocset:
344 verify(r, !r->is_cset(),
345 "Should not have cset regions");
346 break;
347 case ShenandoahVerifier::_verify_regions_notrash_nocset:
348 verify(r, !r->is_trash(),
349 "Should not have trash regions");
350 verify(r, !r->is_cset(),
351 "Should not have cset regions");
352 break;
353 default:
354 ShouldNotReachHere();
355 }
356
357 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
358 "Capacity should match region size");
359
360 verify(r, r->bottom() <= r->top(),
361 "Region top should not be less than bottom");
362
363 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
364 "Region TAMS should not be less than bottom");
365
366 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
367 "Complete TAMS should not be larger than top");
368
369 verify(r, r->get_live_data_bytes() <= r->capacity(),
370 "Live data cannot be larger than capacity");
371
372 verify(r, r->garbage() <= r->capacity(),
373 "Garbage cannot be larger than capacity");
374
375 verify(r, r->used() <= r->capacity(),
376 "Used cannot be larger than capacity");
377
378 verify(r, r->get_shared_allocs() <= r->capacity(),
379 "Shared alloc count should not be larger than capacity");
380
381 verify(r, r->get_tlab_allocs() <= r->capacity(),
382 "TLAB alloc count should not be larger than capacity");
383
384 verify(r, r->get_gclab_allocs() <= r->capacity(),
385 "GCLAB alloc count should not be larger than capacity");
386
387 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
388 "Accurate accounting: shared + TLAB + GCLAB = used");
389
390 verify(r, !r->is_empty() || !r->has_live(),
391 "Empty regions should not have live data");
392
393 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
394 "Transitional: region flags and collection set agree");
395 }
396 };
397
398 class ShenandoahVerifierReachableTask : public AbstractGangTask {
399 private:
400 const char* _label;
401 ShenandoahRootVerifier* _verifier;
402 ShenandoahVerifier::VerifyOptions _options;
403 ShenandoahHeap* _heap;
404 ShenandoahLivenessData* _ld;
405 MarkBitMap* _bitmap;
406 volatile size_t _processed;
407
408 public:
409 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
410 ShenandoahLivenessData* ld,
411 ShenandoahRootVerifier* verifier,
412 const char* label,
413 ShenandoahVerifier::VerifyOptions options) :
414 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
415 _label(label),
416 _verifier(verifier),
417 _options(options),
418 _heap(ShenandoahHeap::heap()),
419 _ld(ld),
420 _bitmap(bitmap),
421 _processed(0) {};
422
423 size_t processed() {
424 return _processed;
425 }
426
427 virtual void work(uint worker_id) {
428 ResourceMark rm;
429 ShenandoahVerifierStack stack;
430
431 // On level 2, we need to only check the roots once.
432 // On level 3, we want to check the roots, and seed the local stack.
433 // It is a lesser evil to accept multiple root scans at level 3, because
434 // extended parallelism would buy us out.
435 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
436 || (ShenandoahVerifyLevel >= 3)) {
437 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
438 ShenandoahMessageBuffer("%s, Roots", _label),
439 _options);
440 if (_heap->unload_classes()) {
441 _verifier->strong_roots_do(&cl);
442 } else {
443 _verifier->roots_do(&cl);
444 }
445 }
446
447 size_t processed = 0;
448
449 if (ShenandoahVerifyLevel >= 3) {
450 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
451 ShenandoahMessageBuffer("%s, Reachable", _label),
452 _options);
453 while (!stack.is_empty()) {
454 processed++;
455 ShenandoahVerifierTask task = stack.pop();
456 cl.verify_oops_from(task.obj());
457 }
458 }
459
460 Atomic::add(processed, &_processed);
461 }
462 };
463
464 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
465 private:
466 const char* _label;
467 ShenandoahVerifier::VerifyOptions _options;
468 ShenandoahHeap *_heap;
469 MarkBitMap* _bitmap;
470 ShenandoahLivenessData* _ld;
471 volatile size_t _claimed;
472 volatile size_t _processed;
473
474 public:
475 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
476 ShenandoahLivenessData* ld,
477 const char* label,
478 ShenandoahVerifier::VerifyOptions options) :
479 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
480 _label(label),
481 _options(options),
482 _heap(ShenandoahHeap::heap()),
483 _bitmap(bitmap),
484 _ld(ld),
485 _claimed(0),
486 _processed(0) {};
487
488 size_t processed() {
489 return _processed;
490 }
491
492 virtual void work(uint worker_id) {
493 ShenandoahVerifierStack stack;
494 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
495 ShenandoahMessageBuffer("%s, Marked", _label),
496 _options);
497
498 while (true) {
499 size_t v = Atomic::add(1u, &_claimed) - 1;
500 if (v < _heap->num_regions()) {
501 ShenandoahHeapRegion* r = _heap->get_region(v);
502 if (!r->is_humongous() && !r->is_trash()) {
503 work_regular(r, stack, cl);
504 } else if (r->is_humongous_start()) {
505 work_humongous(r, stack, cl);
506 }
507 } else {
508 break;
509 }
510 }
511 }
512
513 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
514 size_t processed = 0;
515 HeapWord* obj = r->bottom();
516 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
517 verify_and_follow(obj, stack, cl, &processed);
518 }
519 Atomic::add(processed, &_processed);
520 }
521
522 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
523 size_t processed = 0;
524 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
525 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
526
527 // Bitmaps, before TAMS
528 if (tams > r->bottom()) {
529 HeapWord* start = r->bottom();
530 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
531
532 while (addr < tams) {
533 verify_and_follow(addr, stack, cl, &processed);
534 addr += 1;
535 if (addr < tams) {
536 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
537 }
538 }
539 }
540
541 // Size-based, after TAMS
542 {
543 HeapWord* limit = r->top();
544 HeapWord* addr = tams;
545
546 while (addr < limit) {
547 verify_and_follow(addr, stack, cl, &processed);
548 addr += oop(addr)->size();
549 }
550 }
551
552 Atomic::add(processed, &_processed);
553 }
554
555 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
556 if (!_bitmap->parMark(addr)) return;
557
558 // Verify the object itself:
559 oop obj = oop(addr);
560 cl.verify_oop_standalone(obj);
561
562 // Verify everything reachable from that object too, hopefully realizing
563 // everything was already marked, and never touching further:
564 cl.verify_oops_from(obj);
565 (*processed)++;
566
567 while (!stack.is_empty()) {
568 ShenandoahVerifierTask task = stack.pop();
569 cl.verify_oops_from(task.obj());
570 (*processed)++;
571 }
572 }
573 };
574
575 class VerifyThreadGCState : public ThreadClosure {
576 private:
577 const char* _label;
578 char _expected;
579
580 public:
581 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
582 void do_thread(Thread* t) {
583 char actual = ShenandoahThreadLocalData::gc_state(t);
584 if (actual != _expected) {
585 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
586 }
587 }
588 };
589
590 class ShenandoahGCStateResetter : public StackObj {
591 private:
592 ShenandoahHeap* const _heap;
593 char _gc_state;
594
595 public:
596 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
597 _gc_state = _heap->gc_state();
598 _heap->_gc_state.clear();
599 }
600
601 ~ShenandoahGCStateResetter() {
602 _heap->_gc_state.set(_gc_state);
603 assert(_heap->gc_state() == _gc_state, "Should be restored");
604 }
605 };
606
607 void ShenandoahVerifier::verify_at_safepoint(const char *label,
608 VerifyForwarded forwarded, VerifyMarked marked,
609 VerifyCollectionSet cset,
610 VerifyLiveness liveness, VerifyRegions regions,
611 VerifyGCState gcstate) {
612 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
613 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
614
615 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
616 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
617
618 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
619
620 // GC state checks
621 {
622 char expected = -1;
623 bool enabled;
624 switch (gcstate) {
625 case _verify_gcstate_disable:
626 enabled = false;
627 break;
628 case _verify_gcstate_forwarded:
629 enabled = true;
630 expected = ShenandoahHeap::HAS_FORWARDED;
631 break;
632 case _verify_gcstate_evacuation:
633 enabled = true;
634 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
635 break;
636 case _verify_gcstate_stable:
637 enabled = true;
638 expected = ShenandoahHeap::STABLE;
639 break;
640 default:
641 enabled = false;
642 assert(false, "Unhandled gc-state verification");
643 }
644
645 if (enabled) {
646 char actual = _heap->gc_state();
647 if (actual != expected) {
648 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
649 }
650
651 VerifyThreadGCState vtgcs(label, expected);
652 Threads::java_threads_do(&vtgcs);
653 }
654 }
655
656 // Deactivate barriers temporarily: Verifier wants plain heap accesses
657 ShenandoahGCStateResetter resetter;
658
659 // Heap size checks
660 {
661 ShenandoahHeapLocker lock(_heap->lock());
662
663 ShenandoahCalculateRegionStatsClosure cl;
664 _heap->heap_region_iterate(&cl);
665 size_t heap_used = _heap->used();
666 guarantee(cl.used() == heap_used,
667 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
668 label,
669 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
670 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
671
672 size_t heap_committed = _heap->committed();
673 guarantee(cl.committed() == heap_committed,
674 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
675 label,
676 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
677 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
678 }
679
680 // Internal heap region checks
681 if (ShenandoahVerifyLevel >= 1) {
682 ShenandoahVerifyHeapRegionClosure cl(label, regions);
683 _heap->heap_region_iterate(&cl);
684 }
685
686 OrderAccess::fence();
687 _heap->make_parsable(false);
688
689 // Allocate temporary bitmap for storing marking wavefront:
690 _verification_bit_map->clear();
691
692 // Allocate temporary array for storing liveness data
693 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
694 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
695
696 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
697
698 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
699 // This verifies what application can see, since it only cares about reachable objects.
700 size_t count_reachable = 0;
701 if (ShenandoahVerifyLevel >= 2) {
702 ShenandoahRootVerifier verifier;
703
704 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
705 _heap->workers()->run_task(&task);
706 count_reachable = task.processed();
707 }
708
709 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
710 // not the application, can see during the region scans. There is no reason to process the objects
711 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
712 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
713 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
714 // version
715
716 size_t count_marked = 0;
717 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
718 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
719 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
720 _heap->workers()->run_task(&task);
721 count_marked = task.processed();
722 } else {
723 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
724 }
725
726 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
727 // marked objects.
728
729 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
730 for (size_t i = 0; i < _heap->num_regions(); i++) {
731 ShenandoahHeapRegion* r = _heap->get_region(i);
732
733 juint verf_live = 0;
734 if (r->is_humongous()) {
735 // For humongous objects, test if start region is marked live, and if so,
736 // all humongous regions in that chain have live data equal to their "used".
737 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->index()]);
738 if (start_live > 0) {
739 verf_live = (juint)(r->used() / HeapWordSize);
740 }
741 } else {
742 verf_live = OrderAccess::load_acquire(&ld[r->index()]);
743 }
744
745 size_t reg_live = r->get_live_data_words();
746 if (reg_live != verf_live) {
747 ResourceMark rm;
748 stringStream ss;
749 r->print_on(&ss);
750 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
751 label, reg_live, verf_live, ss.as_string());
752 }
753 }
754 }
755
756 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
757 label, ShenandoahVerifyLevel, count_reachable, count_marked);
758
759 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
760 }
761
762 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
763 verify_at_safepoint(
764 "Generic Verification",
765 _verify_forwarded_allow, // conservatively allow forwarded
766 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
767 _verify_cset_disable, // cset may be inconsistent
768 _verify_liveness_disable, // no reliable liveness data
769 _verify_regions_disable, // no reliable region data
770 _verify_gcstate_disable // no data about gcstate
771 );
772 }
773
774 void ShenandoahVerifier::verify_before_concmark() {
775 verify_at_safepoint(
776 "Before Mark",
777 _verify_forwarded_none, // UR should have fixed up
778 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
779 _verify_cset_none, // UR should have fixed this
780 _verify_liveness_disable, // no reliable liveness data
781 _verify_regions_notrash, // no trash regions
782 _verify_gcstate_stable // there are no forwarded objects
783 );
784 }
785
786 void ShenandoahVerifier::verify_after_concmark() {
787 verify_at_safepoint(
788 "After Mark",
789 _verify_forwarded_none, // no forwarded references
790 _verify_marked_complete, // bitmaps as precise as we can get
791 _verify_cset_none, // no references to cset anymore
792 _verify_liveness_complete, // liveness data must be complete here
793 _verify_regions_disable, // trash regions not yet recycled
794 _verify_gcstate_stable // mark should have stabilized the heap
795 );
796 }
797
798 void ShenandoahVerifier::verify_before_evacuation() {
799 verify_at_safepoint(
800 "Before Evacuation",
801 _verify_forwarded_none, // no forwarded references
802 _verify_marked_complete, // walk over marked objects too
803 _verify_cset_disable, // non-forwarded references to cset expected
804 _verify_liveness_complete, // liveness data must be complete here
805 _verify_regions_disable, // trash regions not yet recycled
806 _verify_gcstate_stable // mark should have stabilized the heap
807 );
808 }
809
810 void ShenandoahVerifier::verify_during_evacuation() {
811 verify_at_safepoint(
812 "During Evacuation",
813 _verify_forwarded_allow, // some forwarded references are allowed
814 _verify_marked_disable, // walk only roots
815 _verify_cset_disable, // some cset references are not forwarded yet
816 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
817 _verify_regions_disable, // trash regions not yet recycled
818 _verify_gcstate_evacuation // evacuation is in progress
819 );
820 }
821
822 void ShenandoahVerifier::verify_after_evacuation() {
823 verify_at_safepoint(
824 "After Evacuation",
825 _verify_forwarded_allow, // objects are still forwarded
826 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
827 _verify_cset_forwarded, // all cset refs are fully forwarded
828 _verify_liveness_disable, // no reliable liveness data anymore
829 _verify_regions_notrash, // trash regions have been recycled already
830 _verify_gcstate_forwarded // evacuation produced some forwarded objects
831 );
832 }
833
834 void ShenandoahVerifier::verify_before_updaterefs() {
835 verify_at_safepoint(
836 "Before Updating References",
837 _verify_forwarded_allow, // forwarded references allowed
838 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
839 _verify_cset_forwarded, // all cset refs are fully forwarded
840 _verify_liveness_disable, // no reliable liveness data anymore
841 _verify_regions_notrash, // trash regions have been recycled already
842 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
843 );
844 }
845
846 void ShenandoahVerifier::verify_after_updaterefs() {
847 verify_at_safepoint(
848 "After Updating References",
849 _verify_forwarded_none, // no forwarded references
850 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
851 _verify_cset_none, // no cset references, all updated
852 _verify_liveness_disable, // no reliable liveness data anymore
853 _verify_regions_nocset, // no cset regions, trash regions have appeared
854 _verify_gcstate_stable // update refs had cleaned up forwarded objects
855 );
856 }
857
858 void ShenandoahVerifier::verify_after_degenerated() {
859 verify_at_safepoint(
860 "After Degenerated GC",
861 _verify_forwarded_none, // all objects are non-forwarded
862 _verify_marked_complete, // all objects are marked in complete bitmap
863 _verify_cset_none, // no cset references
864 _verify_liveness_disable, // no reliable liveness data anymore
865 _verify_regions_notrash_nocset, // no trash, no cset
866 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
867 );
868 }
869
870 void ShenandoahVerifier::verify_before_fullgc() {
871 verify_at_safepoint(
872 "Before Full GC",
873 _verify_forwarded_allow, // can have forwarded objects
874 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
875 _verify_cset_disable, // cset might be foobared
876 _verify_liveness_disable, // no reliable liveness data anymore
877 _verify_regions_disable, // no reliable region data here
878 _verify_gcstate_disable // no reliable gcstate data
879 );
880 }
881
882 void ShenandoahVerifier::verify_after_fullgc() {
883 verify_at_safepoint(
884 "After Full GC",
885 _verify_forwarded_none, // all objects are non-forwarded
886 _verify_marked_complete, // all objects are marked in complete bitmap
887 _verify_cset_none, // no cset references
888 _verify_liveness_disable, // no reliable liveness data anymore
889 _verify_regions_notrash_nocset, // no trash, no cset
890 _verify_gcstate_stable // full gc cleaned up everything
891 );
892 }
893
894 class ShenandoahVerifyNoForwared : public OopClosure {
895 private:
896 template <class T>
897 void do_oop_work(T* p) {
898 T o = RawAccess<>::oop_load(p);
899 if (!CompressedOops::is_null(o)) {
900 oop obj = CompressedOops::decode_not_null(o);
901 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
902 if (obj != fwd) {
903 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
904 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
905 }
906 }
907 }
908
909 public:
910 void do_oop(narrowOop* p) { do_oop_work(p); }
911 void do_oop(oop* p) { do_oop_work(p); }
912 };
913
914 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
915 private:
916 template <class T>
917 void do_oop_work(T* p) {
918 T o = RawAccess<>::oop_load(p);
919 if (!CompressedOops::is_null(o)) {
920 oop obj = CompressedOops::decode_not_null(o);
921 ShenandoahHeap* heap = ShenandoahHeap::heap();
922
923 if (!heap->marking_context()->is_marked(obj)) {
924 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
925 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
926 }
927
928 if (heap->in_collection_set(obj)) {
929 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
930 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
931 }
932
933 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
934 if (obj != fwd) {
935 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
936 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
937 }
938 }
939 }
940
941 public:
942 void do_oop(narrowOop* p) { do_oop_work(p); }
943 void do_oop(oop* p) { do_oop_work(p); }
944 };
945
946 void ShenandoahVerifier::verify_roots_in_to_space() {
947 ShenandoahRootVerifier verifier;
948 ShenandoahVerifyInToSpaceClosure cl;
949 verifier.oops_do(&cl);
950 }
951
952 void ShenandoahVerifier::verify_roots_no_forwarded() {
953 ShenandoahRootVerifier verifier;
954 ShenandoahVerifyNoForwared cl;
955 verifier.oops_do(&cl);
956 }
957
958 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
959 ShenandoahRootVerifier verifier;
960 verifier.excludes(types);
961 ShenandoahVerifyNoForwared cl;
962 verifier.oops_do(&cl);
963 }
964