1 /*
2 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
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 "memory/allocation.hpp"
27 #include "gc_implementation/shenandoah/shenandoahAsserts.hpp"
28 #include "gc_implementation/shenandoah/shenandoahHeap.hpp"
29 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc_implementation/shenandoah/shenandoahMarkingContext.inline.hpp"
31 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp"
32 #include "gc_implementation/shenandoah/brooksPointer.hpp"
33 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp"
34
35 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
36 #ifdef verify_oop
37 #undef verify_oop
38 #endif
39
40 class ShenandoahVerifyOopClosure : public ExtendedOopClosure {
41 private:
42 const char* _phase;
43 ShenandoahVerifier::VerifyOptions _options;
44 ShenandoahVerifierStack* _stack;
45 ShenandoahHeap* _heap;
46 MarkBitMap* _map;
47 ShenandoahLivenessData* _ld;
48 void* _interior_loc;
49 oop _loc;
50
51 public:
52 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
53 const char* phase, ShenandoahVerifier::VerifyOptions options) :
54 _phase(phase),
55 _options(options),
56 _stack(stack),
57 _heap(ShenandoahHeap::heap()),
58 _map(map),
59 _ld(ld),
60 _interior_loc(NULL),
61 _loc(NULL) { }
62
63 private:
64 void verify(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
65 if (!test) {
66 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
67 }
68 }
69
70 template <class T>
71 void do_oop_work(T* p) {
72 T o = oopDesc::load_heap_oop(p);
73 if (!oopDesc::is_null(o)) {
74 oop obj = oopDesc::decode_heap_oop_not_null(o);
75
76 // Single threaded verification can use faster non-atomic stack and bitmap
77 // methods.
78 //
79 // For performance reasons, only fully verify non-marked field values.
80 // We are here when the host object for *p is already marked.
81
82 HeapWord* addr = (HeapWord*) obj;
83 if (_map->parMark(addr)) {
84 verify_oop_at(p, obj);
85 _stack->push(ShenandoahVerifierTask(obj));
86 }
87 }
88 }
89
90 void verify_oop(oop obj) {
91 // Perform consistency checks with gradually decreasing safety level. This guarantees
92 // that failure report would not try to touch something that was not yet verified to be
93 // safe to process.
94
95 verify(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
96 "oop must be in heap");
97 verify(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),
98 "oop must be aligned");
99
100 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
101 Klass* obj_klass = obj->klass_or_null();
102
103 // Verify that obj is not in dead space:
104 {
105 // Do this before touching obj->size()
106 verify(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
107 "Object klass pointer should not be NULL");
108 verify(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
109 "Object klass pointer must go to metaspace");
110
111 HeapWord *obj_addr = (HeapWord *) obj;
112 verify(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
113 "Object start should be within the region");
114
115 if (!obj_reg->is_humongous()) {
116 verify(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
117 "Object end should be within the region");
118 } else {
119 size_t humongous_start = obj_reg->region_number();
120 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
121 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
122 verify(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
123 "Humongous object is in continuation that fits it");
124 }
125 }
126
127 // ------------ obj is safe at this point --------------
128
129 verify(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
130 "Object should be in active region");
131
132 switch (_options._verify_liveness) {
133 case ShenandoahVerifier::_verify_liveness_disable:
134 // skip
135 break;
136 case ShenandoahVerifier::_verify_liveness_complete:
137 Atomic::add(obj->size() + BrooksPointer::word_size(), &_ld[obj_reg->region_number()]);
138 // fallthrough for fast failure for un-live regions:
139 case ShenandoahVerifier::_verify_liveness_conservative:
140 verify(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
141 "Object must belong to region with live data");
142 break;
143 default:
144 assert(false, "Unhandled liveness verification");
145 }
146 }
147
148 oop fwd = (oop) BrooksPointer::get_raw_unchecked(obj);
149
150 ShenandoahHeapRegion* fwd_reg = NULL;
151
152 if (!oopDesc::unsafe_equals(obj, fwd)) {
153 verify(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
154 "Forwardee must be in heap");
155 verify(ShenandoahAsserts::_safe_oop, obj, !oopDesc::is_null(fwd),
156 "Forwardee is set");
157 verify(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),
158 "Forwardee must be aligned");
159
160 // Do this before touching fwd->size()
161 Klass* fwd_klass = fwd->klass_or_null();
162 verify(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
163 "Forwardee klass pointer should not be NULL");
164 verify(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
165 "Forwardee klass pointer must go to metaspace");
166 verify(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
167 "Forwardee klass pointer must go to metaspace");
168
169 fwd_reg = _heap->heap_region_containing(fwd);
170
171 // Verify that forwardee is not in the dead space:
172 verify(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
173 "Should have no humongous forwardees");
174
175 HeapWord *fwd_addr = (HeapWord *) fwd;
176 verify(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
177 "Forwardee start should be within the region");
178 verify(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
179 "Forwardee end should be within the region");
180
181 oop fwd2 = (oop) BrooksPointer::get_raw_unchecked(fwd);
182 verify(ShenandoahAsserts::_safe_oop, obj, oopDesc::unsafe_equals(fwd, fwd2),
183 "Double forwarding");
184 } else {
185 fwd_reg = obj_reg;
186 }
187
188 // ------------ obj and fwd are safe at this point --------------
189
190 switch (_options._verify_marked) {
191 case ShenandoahVerifier::_verify_marked_disable:
192 // skip
193 break;
194 case ShenandoahVerifier::_verify_marked_next:
195 verify(ShenandoahAsserts::_safe_all, obj, _heap->next_marking_context()->is_marked(obj),
196 "Must be marked in next bitmap");
197 break;
198 case ShenandoahVerifier::_verify_marked_complete:
199 verify(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
200 "Must be marked in complete bitmap");
201 break;
202 default:
203 assert(false, "Unhandled mark verification");
204 }
205
206 switch (_options._verify_forwarded) {
207 case ShenandoahVerifier::_verify_forwarded_disable:
208 // skip
209 break;
210 case ShenandoahVerifier::_verify_forwarded_none: {
211 verify(ShenandoahAsserts::_safe_all, obj, oopDesc::unsafe_equals(obj, fwd),
212 "Should not be forwarded");
213 break;
214 }
215 case ShenandoahVerifier::_verify_forwarded_allow: {
216 if (!oopDesc::unsafe_equals(obj, fwd)) {
217 verify(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
218 "Forwardee should be in another region");
219 }
220 break;
221 }
222 default:
223 assert(false, "Unhandled forwarding verification");
224 }
225
226 switch (_options._verify_cset) {
227 case ShenandoahVerifier::_verify_cset_disable:
228 // skip
229 break;
230 case ShenandoahVerifier::_verify_cset_none:
231 verify(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
232 "Should not have references to collection set");
233 break;
234 case ShenandoahVerifier::_verify_cset_forwarded:
235 if (_heap->in_collection_set(obj)) {
236 verify(ShenandoahAsserts::_safe_all, obj, !oopDesc::unsafe_equals(obj, fwd),
237 "Object in collection set, should have forwardee");
238 }
239 break;
240 default:
241 assert(false, "Unhandled cset verification");
242 }
243 }
244
245 public:
246
247 /**
248 * Verify object with known interior reference.
249 * @param p interior reference where the object is referenced from; can be off-heap
250 * @param obj verified object
251 */
252 template <class T>
253 void verify_oop_at(T* p, oop obj) {
254 _interior_loc = p;
255 verify_oop(obj);
256 _interior_loc = NULL;
257 }
258
259 /**
260 * Verify object without known interior reference.
261 * Useful when picking up the object at known offset in heap,
262 * but without knowing what objects reference it.
263 * @param obj verified object
264 */
265 void verify_oop_standalone(oop obj) {
266 _interior_loc = NULL;
267 verify_oop(obj);
268 _interior_loc = NULL;
269 }
270
271 /**
272 * Verify oop fields from this object.
273 * @param obj host object for verified fields
274 */
275 void verify_oops_from(oop obj) {
276 _loc = obj;
277 obj->oop_iterate(this);
278 _loc = NULL;
279 }
280
281
282 void do_oop(oop* p) { do_oop_work(p); }
283 void do_oop(narrowOop* p) { do_oop_work(p); }
284 };
285
286 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
287 private:
288 size_t _used, _committed, _garbage;
289 public:
290 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
291
292 bool heap_region_do(ShenandoahHeapRegion* r) {
293 _used += r->used();
294 _garbage += r->garbage();
295 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
296 return false;
297 }
298
299 size_t used() { return _used; }
300 size_t committed() { return _committed; }
301 size_t garbage() { return _garbage; }
302 };
303
304 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
305 private:
306 ShenandoahHeap* _heap;
307 const char* _phase;
308 ShenandoahVerifier::VerifyRegions _regions;
309 public:
310 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
311 _heap(ShenandoahHeap::heap()),
312 _phase(phase),
313 _regions(regions) {};
314
315 void print_failure(ShenandoahHeapRegion* r, const char* label) {
316 ResourceMark rm;
317
318 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
319
320 stringStream ss;
321 r->print_on(&ss);
322 msg.append("%s", ss.as_string());
323
324 report_vm_error(__FILE__, __LINE__, msg.buffer());
325 }
326
327 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
328 if (!test) {
329 print_failure(r, msg);
330 }
331 }
332
333 bool heap_region_do(ShenandoahHeapRegion* r) {
334 switch (_regions) {
335 case ShenandoahVerifier::_verify_regions_disable:
336 break;
337 case ShenandoahVerifier::_verify_regions_notrash:
338 verify(r, !r->is_trash(),
339 "Should not have trash regions");
340 break;
341 case ShenandoahVerifier::_verify_regions_nocset:
342 verify(r, !r->is_cset(),
343 "Should not have cset regions");
344 break;
345 case ShenandoahVerifier::_verify_regions_notrash_nocset:
346 verify(r, !r->is_trash(),
347 "Should not have trash regions");
348 verify(r, !r->is_cset(),
349 "Should not have cset regions");
350 break;
351 default:
352 ShouldNotReachHere();
353 }
354
355 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
356 "Capacity should match region size");
357
358 verify(r, r->bottom() <= _heap->complete_marking_context()->top_at_mark_start(r->region_number()),
359 "Region top should not be less than bottom");
360
361 verify(r, _heap->complete_marking_context()->top_at_mark_start(r->region_number()) <= r->top(),
362 "Complete TAMS should not be larger than top");
363
364 verify(r, r->get_live_data_bytes() <= r->capacity(),
365 "Live data cannot be larger than capacity");
366
367 verify(r, r->garbage() <= r->capacity(),
368 "Garbage cannot be larger than capacity");
369
370 verify(r, r->used() <= r->capacity(),
371 "Used cannot be larger than capacity");
372
373 verify(r, r->get_shared_allocs() <= r->capacity(),
374 "Shared alloc count should not be larger than capacity");
375
376 verify(r, r->get_tlab_allocs() <= r->capacity(),
377 "TLAB alloc count should not be larger than capacity");
378
379 verify(r, r->get_gclab_allocs() <= r->capacity(),
380 "GCLAB alloc count should not be larger than capacity");
381
382 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
383 "Accurate accounting: shared + TLAB + GCLAB = used");
384
385 verify(r, !r->is_empty() || !r->has_live(),
386 "Empty regions should not have live data");
387
388 verify(r, r->is_cset() == r->in_collection_set(),
389 "Transitional: region flags and collection set agree");
390
391 return false;
392 }
393 };
394
395 class ShenandoahVerifierReachableTask : public AbstractGangTask {
396 private:
397 const char* _label;
398 ShenandoahRootProcessor* _rp;
399 ShenandoahVerifier::VerifyOptions _options;
400 ShenandoahHeap* _heap;
401 ShenandoahLivenessData* _ld;
402 MarkBitMap* _bitmap;
403 volatile jlong _processed;
404
405 public:
406 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
407 ShenandoahLivenessData* ld,
408 ShenandoahRootProcessor* rp,
409 const char* label,
410 ShenandoahVerifier::VerifyOptions options) :
411 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
412 _label(label),
413 _rp(rp),
414 _options(options),
415 _heap(ShenandoahHeap::heap()),
416 _ld(ld),
417 _bitmap(bitmap),
418 _processed(0) {};
419
420 size_t processed() {
421 return (size_t) _processed;
422 }
423
424 virtual void work(uint worker_id) {
425 ResourceMark rm;
426 ShenandoahVerifierStack stack;
427
428 // On level 2, we need to only check the roots once.
429 // On level 3, we want to check the roots, and seed the local stack.
430 // It is a lesser evil to accept multiple root scans at level 3, because
431 // extended parallelism would buy us out.
432 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
433 || (ShenandoahVerifyLevel >= 3)) {
434 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
435 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Roots", _label),
436 _options);
437 _rp->process_all_roots_slow(&cl);
438 }
439
440 jlong processed = 0;
441
442 if (ShenandoahVerifyLevel >= 3) {
443 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
444 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Reachable", _label),
445 _options);
446 while (!stack.is_empty()) {
447 processed++;
448 ShenandoahVerifierTask task = stack.pop();
449 cl.verify_oops_from(task.obj());
450 }
451 }
452
453 Atomic::add(processed, &_processed);
454 }
455 };
456
457 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
458 private:
459 const char* _label;
460 ShenandoahVerifier::VerifyOptions _options;
461 ShenandoahHeap *_heap;
462 ShenandoahLivenessData* _ld;
463 MarkBitMap* _bitmap;
464 volatile jint _claimed;
465 volatile jlong _processed;
466
467 public:
468 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
469 ShenandoahLivenessData* ld,
470 const char* label,
471 ShenandoahVerifier::VerifyOptions options) :
472 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
473 _label(label),
474 _options(options),
475 _heap(ShenandoahHeap::heap()),
476 _bitmap(bitmap),
477 _ld(ld),
478 _claimed(0),
479 _processed(0) {};
480
481 size_t processed() {
482 return (size_t) _processed;
483 }
484
485 virtual void work(uint worker_id) {
486 ShenandoahVerifierStack stack;
487 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
488 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Marked", _label),
489 _options);
490 assert((size_t)max_jint >= _heap->num_regions(), "Too many regions");
491 while (true) {
492 size_t v = (size_t) (Atomic::add(1, &_claimed) - 1);
493 if (v < _heap->num_regions()) {
494 ShenandoahHeapRegion* r = _heap->get_region(v);
495 if (!r->is_humongous() && !r->is_trash()) {
496 work_regular(r, stack, cl);
497 } else if (r->is_humongous_start()) {
498 work_humongous(r, stack, cl);
499 }
500 } else {
501 break;
502 }
503 }
504 }
505
506 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
507 jlong processed = 0;
508 HeapWord* obj = r->bottom() + BrooksPointer::word_size();
509 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
510 verify_and_follow(obj, stack, cl, &processed);
511 }
512 Atomic::add(processed, &_processed);
513 }
514
515 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
516 jlong processed = 0;
517 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
518 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r->region_number());
519
520 // Bitmaps, before TAMS
521 if (tams > r->bottom()) {
522 HeapWord* start = r->bottom() + BrooksPointer::word_size();
523 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
524
525 while (addr < tams) {
526 verify_and_follow(addr, stack, cl, &processed);
527 addr += BrooksPointer::word_size();
528 if (addr < tams) {
529 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
530 }
531 }
532 }
533
534 // Size-based, after TAMS
535 {
536 HeapWord* limit = r->top();
537 HeapWord* addr = tams + BrooksPointer::word_size();
538
539 while (addr < limit) {
540 verify_and_follow(addr, stack, cl, &processed);
541 addr += oop(addr)->size() + BrooksPointer::word_size();
542 }
543 }
544
545 Atomic::add(processed, &_processed);
546 }
547
548 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, jlong *processed) {
549 if (!_bitmap->parMark(addr)) return;
550
551 // Verify the object itself:
552 oop obj = oop(addr);
553 cl.verify_oop_standalone(obj);
554
555 // Verify everything reachable from that object too, hopefully realizing
556 // everything was already marked, and never touching further:
557 cl.verify_oops_from(obj);
558 (*processed)++;
559
560 while (!stack.is_empty()) {
561 ShenandoahVerifierTask task = stack.pop();
562 cl.verify_oops_from(task.obj());
563 (*processed)++;
564 }
565 }
566 };
567
568 class VerifyThreadGCState : public ThreadClosure {
569 private:
570 const char* _label;
571 char _expected;
572
573 public:
574 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
575 void do_thread(Thread* t) {
576 assert(t->is_Java_thread(), "sanity");
577 char actual = ((JavaThread*)t)->gc_state();
578 if (actual != _expected) {
579 fatal(err_msg("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual));
580 }
581 }
582 };
583
584
585 void ShenandoahVerifier::verify_at_safepoint(const char *label,
586 VerifyForwarded forwarded, VerifyMarked marked,
587 VerifyCollectionSet cset,
588 VerifyLiveness liveness, VerifyRegions regions,
589 VerifyGCState gcstate) {
590 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
591 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
592
593 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
594 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
595
596 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
597
598 // GC state checks
599 {
600 char expected = -1;
601 bool enabled;
602 switch (gcstate) {
603 case _verify_gcstate_disable:
604 enabled = false;
605 break;
606 case _verify_gcstate_forwarded:
607 enabled = true;
608 expected = ShenandoahHeap::HAS_FORWARDED;
609 break;
610 case _verify_gcstate_stable:
611 enabled = true;
612 expected = ShenandoahHeap::STABLE;
613 break;
614 default:
615 enabled = false;
616 assert(false, "Unhandled gc-state verification");
617 }
618
619 if (enabled) {
620 char actual = _heap->gc_state();
621 if (actual != expected) {
622 fatal(err_msg("%s: Global gc-state: expected %d, actual %d", label, expected, actual));
623 }
624
625 VerifyThreadGCState vtgcs(label, expected);
626 Threads::java_threads_do(&vtgcs);
627 }
628 }
629
630 // Heap size checks
631 {
632 ShenandoahHeapLocker lock(_heap->lock());
633
634 ShenandoahCalculateRegionStatsClosure cl;
635 _heap->heap_region_iterate(&cl);
636 size_t heap_used = _heap->used();
637 guarantee(cl.used() == heap_used,
638 err_msg("%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
639 label, heap_used/K, cl.used()/K));
640
641 size_t heap_committed = _heap->committed();
642 guarantee(cl.committed() == heap_committed,
643 err_msg("%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
644 label, heap_committed/K, cl.committed()/K));
645 }
646
647 // Internal heap region checks
648 if (ShenandoahVerifyLevel >= 1) {
649 ShenandoahVerifyHeapRegionClosure cl(label, regions);
650 _heap->heap_region_iterate(&cl,
651 /* skip_cset = */ false,
652 /* skip_humongous_cont = */ false);
653 }
654
655 OrderAccess::fence();
656 _heap->make_parsable(false);
657
658 // Allocate temporary bitmap for storing marking wavefront:
659 MemRegion mr = MemRegion(_verification_bit_map->startWord(), _verification_bit_map->endWord());
660 _verification_bit_map->clear_range_large(mr);
661
662 // Allocate temporary array for storing liveness data
663 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
664 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
665
666 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
667
668 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
669 // This verifies what application can see, since it only cares about reachable objects.
670 size_t count_reachable = 0;
671 if (ShenandoahVerifyLevel >= 2) {
672 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
673 ShenandoahPhaseTimings::_num_phases); // no need for stats
674
675 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
676 _heap->workers()->run_task(&task);
677 count_reachable = task.processed();
678 }
679
680 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
681 // not the application, can see during the region scans. There is no reason to process the objects
682 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
683 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
684 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
685 // version
686
687 size_t count_marked = 0;
688 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
689 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
690 _heap->workers()->run_task(&task);
691 count_marked = task.processed();
692 } else {
693 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_next || marked == _verify_marked_disable, "Should be");
694 }
695
696 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
697 // marked objects.
698
699 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
700 for (size_t i = 0; i < _heap->num_regions(); i++) {
701 ShenandoahHeapRegion* r = _heap->get_region(i);
702
703 jint verf_live = 0;
704 if (r->is_humongous()) {
705 // For humongous objects, test if start region is marked live, and if so,
706 // all humongous regions in that chain have live data equal to their "used".
707 jint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
708 if (start_live > 0) {
709 verf_live = (jint)(r->used() / HeapWordSize);
710 }
711 } else {
712 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
713 }
714
715 size_t reg_live = r->get_live_data_words();
716 if (reg_live != (size_t)verf_live) {
717 ResourceMark rm;
718 stringStream ss;
719 r->print_on(&ss);
720 fatal(err_msg("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " INT32_FORMAT "\n%s",
721 label, reg_live, verf_live, ss.as_string()));
722 }
723 }
724 }
725
726 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
727 label, ShenandoahVerifyLevel, count_reachable, count_marked);
728
729 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld, mtGC);
730 }
731
732 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
733 verify_at_safepoint(
734 "Generic Verification",
735 _verify_forwarded_allow, // conservatively allow forwarded
736 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
737 _verify_cset_disable, // cset may be inconsistent
738 _verify_liveness_disable, // no reliable liveness data
739 _verify_regions_disable, // no reliable region data
740 _verify_gcstate_disable // no data about gcstate
741 );
742 }
743
744 void ShenandoahVerifier::verify_before_concmark() {
745 if (_heap->has_forwarded_objects()) {
746 verify_at_safepoint(
747 "Before Mark",
748 _verify_forwarded_allow, // may have forwarded references
749 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
750 _verify_cset_forwarded, // allow forwarded references to cset
751 _verify_liveness_disable, // no reliable liveness data
752 _verify_regions_notrash, // no trash regions
753 _verify_gcstate_forwarded // there are forwarded objects
754 );
755 } else {
756 verify_at_safepoint(
757 "Before Mark",
758 _verify_forwarded_none, // UR should have fixed up
759 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
760 _verify_cset_none, // UR should have fixed this
761 _verify_liveness_disable, // no reliable liveness data
762 _verify_regions_notrash, // no trash regions
763 _verify_gcstate_stable // there are no forwarded objects
764 );
765 }
766 }
767
768 void ShenandoahVerifier::verify_after_concmark() {
769 verify_at_safepoint(
770 "After Mark",
771 _verify_forwarded_none, // no forwarded references
772 _verify_marked_complete, // bitmaps as precise as we can get
773 _verify_cset_none, // no references to cset anymore
774 _verify_liveness_complete, // liveness data must be complete here
775 _verify_regions_disable, // trash regions not yet recycled
776 _verify_gcstate_stable // mark should have stabilized the heap
777 );
778 }
779
780 void ShenandoahVerifier::verify_before_evacuation() {
781 // Evacuation is always preceded by mark, but we want to have a sanity check after
782 // selecting the collection set, and (immediate) regions recycling
783 verify_at_safepoint(
784 "Before Evacuation",
785 _verify_forwarded_none, // no forwarded references
786 _verify_marked_complete, // walk over marked objects too
787 _verify_cset_disable, // skip, verified after mark
788 _verify_liveness_disable, // skip, verified after mark
789 _verify_regions_disable, // trash regions not yet recycled
790 _verify_gcstate_stable // mark should have stabilized the heap
791 );
792 }
793
794 void ShenandoahVerifier::verify_after_evacuation() {
795 verify_at_safepoint(
796 "After Evacuation",
797 _verify_forwarded_allow, // objects are still forwarded
798 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
799 _verify_cset_forwarded, // all cset refs are fully forwarded
800 _verify_liveness_disable, // no reliable liveness data anymore
801 _verify_regions_notrash, // trash regions have been recycled already
802 _verify_gcstate_forwarded // evacuation produced some forwarded objects
803 );
804 }
805
806 void ShenandoahVerifier::verify_before_updaterefs() {
807 verify_at_safepoint(
808 "Before Updating References",
809 _verify_forwarded_allow, // forwarded references allowed
810 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
811 _verify_cset_forwarded, // all cset refs are fully forwarded
812 _verify_liveness_disable, // no reliable liveness data anymore
813 _verify_regions_notrash, // trash regions have been recycled already
814 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
815 );
816 }
817
818 void ShenandoahVerifier::verify_after_updaterefs() {
819 verify_at_safepoint(
820 "After Updating References",
821 _verify_forwarded_none, // no forwarded references
822 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
823 _verify_cset_none, // no cset references, all updated
824 _verify_liveness_disable, // no reliable liveness data anymore
825 _verify_regions_nocset, // no cset regions, trash regions have appeared
826 _verify_gcstate_stable // update refs had cleaned up forwarded objects
827 );
828 }
829
830 void ShenandoahVerifier::verify_before_fullgc() {
831 verify_at_safepoint(
832 "Before Full GC",
833 _verify_forwarded_allow, // can have forwarded objects
834 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
835 _verify_cset_disable, // cset might be foobared
836 _verify_liveness_disable, // no reliable liveness data anymore
837 _verify_regions_disable, // no reliable region data here
838 _verify_gcstate_disable // no reliable gcstate data
839 );
840 }
841
842 void ShenandoahVerifier::verify_after_fullgc() {
843 verify_at_safepoint(
844 "After Full GC",
845 _verify_forwarded_none, // all objects are non-forwarded
846 _verify_marked_complete, // all objects are marked in complete bitmap
847 _verify_cset_none, // no cset references
848 _verify_liveness_disable, // no reliable liveness data anymore
849 _verify_regions_notrash_nocset, // no trash, no cset
850 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
851 );
852 }
853
854 void ShenandoahVerifier::verify_after_degenerated() {
855 verify_at_safepoint(
856 "After Degenerated GC",
857 _verify_forwarded_none, // all objects are non-forwarded
858 _verify_marked_complete, // all objects are marked in complete bitmap
859 _verify_cset_none, // no cset references
860 _verify_liveness_disable, // no reliable liveness data anymore
861 _verify_regions_notrash_nocset, // no trash, no cset
862 _verify_gcstate_stable // full gc cleaned up everything
863 );
864 }