1 /*
2 * Copyright (c) 2017, 2018, 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/shenandoahBrooksPointer.hpp"
28 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
29 #include "gc/shenandoah/shenandoahHeap.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
32 #include "gc/shenandoah/shenandoahTaskqueue.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->par_mark(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->region_number();
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(obj->size() + ShenandoahBrooksPointer::word_size(), &_ld[obj_reg->region_number()]);
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) ShenandoahBrooksPointer::get_raw_unchecked(obj);
153
154 ShenandoahHeapRegion* fwd_reg = NULL;
155
156 if (!oopDesc::equals_raw(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) ShenandoahBrooksPointer::get_raw_unchecked(fwd);
186 check(ShenandoahAsserts::_safe_oop, obj, oopDesc::equals_raw(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, oopDesc::equals_raw(obj, fwd),
216 "Should not be forwarded");
217 break;
218 }
219 case ShenandoahVerifier::_verify_forwarded_allow: {
220 if (!oopDesc::equals_raw(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, !oopDesc::equals_raw(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 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
397 "Non-empty regions should have first seqnum set");
398
399 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
400 "Non-empty regions should have first seqnum set to either GC or mutator");
401
402 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
403 "Non-empty regions should have last seqnum set");
404
405 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
406 "Non-empty regions should have last seqnum set to either GC or mutator");
407
408 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
409 "First seqnum should not be greater than last timestamp");
410
411 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
412 "First mutator seqnum should not be greater than last seqnum");
413
414 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
415 "First GC seqnum should not be greater than last seqnum");
416 }
417 };
418
419 class ShenandoahVerifierReachableTask : public AbstractGangTask {
420 private:
421 const char* _label;
422 ShenandoahRootProcessor* _rp;
423 ShenandoahVerifier::VerifyOptions _options;
424 ShenandoahHeap* _heap;
425 ShenandoahLivenessData* _ld;
426 MarkBitMap* _bitmap;
427 volatile size_t _processed;
428
429 public:
430 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
431 ShenandoahLivenessData* ld,
432 ShenandoahRootProcessor* rp,
433 const char* label,
434 ShenandoahVerifier::VerifyOptions options) :
435 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
436 _label(label),
437 _rp(rp),
438 _options(options),
439 _heap(ShenandoahHeap::heap()),
440 _ld(ld),
441 _bitmap(bitmap),
442 _processed(0) {};
443
444 size_t processed() {
445 return _processed;
446 }
447
448 virtual void work(uint worker_id) {
449 ResourceMark rm;
450 ShenandoahVerifierStack stack;
451
452 // On level 2, we need to only check the roots once.
453 // On level 3, we want to check the roots, and seed the local stack.
454 // It is a lesser evil to accept multiple root scans at level 3, because
455 // extended parallelism would buy us out.
456 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
457 || (ShenandoahVerifyLevel >= 3)) {
458 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
459 ShenandoahMessageBuffer("%s, Roots", _label),
460 _options);
461 _rp->process_all_roots_slow(&cl);
462 }
463
464 size_t processed = 0;
465
466 if (ShenandoahVerifyLevel >= 3) {
467 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
468 ShenandoahMessageBuffer("%s, Reachable", _label),
469 _options);
470 while (!stack.is_empty()) {
471 processed++;
472 ShenandoahVerifierTask task = stack.pop();
473 cl.verify_oops_from(task.obj());
474 }
475 }
476
477 Atomic::add(processed, &_processed);
478 }
479 };
480
481 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
482 private:
483 const char* _label;
484 ShenandoahVerifier::VerifyOptions _options;
485 ShenandoahHeap *_heap;
486 MarkBitMap* _bitmap;
487 ShenandoahLivenessData* _ld;
488 volatile size_t _claimed;
489 volatile size_t _processed;
490
491 public:
492 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
493 ShenandoahLivenessData* ld,
494 const char* label,
495 ShenandoahVerifier::VerifyOptions options) :
496 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
497 _label(label),
498 _options(options),
499 _heap(ShenandoahHeap::heap()),
500 _bitmap(bitmap),
501 _ld(ld),
502 _claimed(0),
503 _processed(0) {};
504
505 size_t processed() {
506 return _processed;
507 }
508
509 virtual void work(uint worker_id) {
510 ShenandoahVerifierStack stack;
511 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
512 ShenandoahMessageBuffer("%s, Marked", _label),
513 _options);
514
515 while (true) {
516 size_t v = Atomic::add(1u, &_claimed) - 1;
517 if (v < _heap->num_regions()) {
518 ShenandoahHeapRegion* r = _heap->get_region(v);
519 if (!r->is_humongous() && !r->is_trash()) {
520 work_regular(r, stack, cl);
521 } else if (r->is_humongous_start()) {
522 work_humongous(r, stack, cl);
523 }
524 } else {
525 break;
526 }
527 }
528 }
529
530 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
531 size_t processed = 0;
532 HeapWord* obj = r->bottom() + ShenandoahBrooksPointer::word_size();
533 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
534 verify_and_follow(obj, stack, cl, &processed);
535 }
536 Atomic::add(processed, &_processed);
537 }
538
539 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
540 size_t processed = 0;
541 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
542 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
543
544 // Bitmaps, before TAMS
545 if (tams > r->bottom()) {
546 HeapWord* start = r->bottom() + ShenandoahBrooksPointer::word_size();
547 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
548
549 while (addr < tams) {
550 verify_and_follow(addr, stack, cl, &processed);
551 addr += ShenandoahBrooksPointer::word_size();
552 if (addr < tams) {
553 addr = mark_bit_map->get_next_marked_addr(addr, tams);
554 }
555 }
556 }
557
558 // Size-based, after TAMS
559 {
560 HeapWord* limit = r->top();
561 HeapWord* addr = tams + ShenandoahBrooksPointer::word_size();
562
563 while (addr < limit) {
564 verify_and_follow(addr, stack, cl, &processed);
565 addr += oop(addr)->size() + ShenandoahBrooksPointer::word_size();
566 }
567 }
568
569 Atomic::add(processed, &_processed);
570 }
571
572 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
573 if (!_bitmap->par_mark(addr)) return;
574
575 // Verify the object itself:
576 oop obj = oop(addr);
577 cl.verify_oop_standalone(obj);
578
579 // Verify everything reachable from that object too, hopefully realizing
580 // everything was already marked, and never touching further:
581 cl.verify_oops_from(obj);
582 (*processed)++;
583
584 while (!stack.is_empty()) {
585 ShenandoahVerifierTask task = stack.pop();
586 cl.verify_oops_from(task.obj());
587 (*processed)++;
588 }
589 }
590 };
591
592 class VerifyThreadGCState : public ThreadClosure {
593 private:
594 const char* _label;
595 char _expected;
596
597 public:
598 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
599 void do_thread(Thread* t) {
600 char actual = ShenandoahThreadLocalData::gc_state(t);
601 if (actual != _expected) {
602 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
603 }
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_stable:
633 enabled = true;
634 expected = ShenandoahHeap::STABLE;
635 break;
636 default:
637 enabled = false;
638 assert(false, "Unhandled gc-state verification");
639 }
640
641 if (enabled) {
642 char actual = _heap->gc_state();
643 if (actual != expected) {
644 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
645 }
646
647 VerifyThreadGCState vtgcs(label, expected);
648 Threads::java_threads_do(&vtgcs);
649 }
650 }
651
652 // Heap size checks
653 {
654 ShenandoahHeapLocker lock(_heap->lock());
655
656 ShenandoahCalculateRegionStatsClosure cl;
657 _heap->heap_region_iterate(&cl);
658 size_t heap_used = _heap->used();
659 guarantee(cl.used() == heap_used,
660 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
661 label, heap_used/K, cl.used()/K);
662
663 size_t heap_committed = _heap->committed();
664 guarantee(cl.committed() == heap_committed,
665 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
666 label, heap_committed/K, cl.committed()/K);
667 }
668
669 // Internal heap region checks
670 if (ShenandoahVerifyLevel >= 1) {
671 ShenandoahVerifyHeapRegionClosure cl(label, regions);
672 _heap->heap_region_iterate(&cl);
673 }
674
675 OrderAccess::fence();
676 _heap->make_parsable(false);
677
678 // Allocate temporary bitmap for storing marking wavefront:
679 _verification_bit_map->clear();
680
681 // Allocate temporary array for storing liveness data
682 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
683 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
684
685 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
686
687 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
688 // This verifies what application can see, since it only cares about reachable objects.
689 size_t count_reachable = 0;
690 if (ShenandoahVerifyLevel >= 2) {
691 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
692 ShenandoahPhaseTimings::_num_phases); // no need for stats
693
694 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
695 _heap->workers()->run_task(&task);
696 count_reachable = task.processed();
697 }
698
699 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
700 // not the application, can see during the region scans. There is no reason to process the objects
701 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
702 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
703 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
704 // version
705
706 size_t count_marked = 0;
707 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
708 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
709 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
710 _heap->workers()->run_task(&task);
711 count_marked = task.processed();
712 } else {
713 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
714 }
715
716 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
717 // marked objects.
718
719 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
720 for (size_t i = 0; i < _heap->num_regions(); i++) {
721 ShenandoahHeapRegion* r = _heap->get_region(i);
722
723 juint verf_live = 0;
724 if (r->is_humongous()) {
725 // For humongous objects, test if start region is marked live, and if so,
726 // all humongous regions in that chain have live data equal to their "used".
727 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
728 if (start_live > 0) {
729 verf_live = (juint)(r->used() / HeapWordSize);
730 }
731 } else {
732 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
733 }
734
735 size_t reg_live = r->get_live_data_words();
736 if (reg_live != verf_live) {
737 ResourceMark rm;
738 stringStream ss;
739 r->print_on(&ss);
740 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
741 label, reg_live, verf_live, ss.as_string());
742 }
743 }
744 }
745
746 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
747 label, ShenandoahVerifyLevel, count_reachable, count_marked);
748
749 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
750 }
751
752 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
753 verify_at_safepoint(
754 "Generic Verification",
755 _verify_forwarded_allow, // conservatively allow forwarded
756 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
757 _verify_cset_disable, // cset may be inconsistent
758 _verify_liveness_disable, // no reliable liveness data
759 _verify_regions_disable, // no reliable region data
760 _verify_gcstate_disable // no data about gcstate
761 );
762 }
763
764 void ShenandoahVerifier::verify_before_concmark() {
765 if (_heap->has_forwarded_objects()) {
766 verify_at_safepoint(
767 "Before Mark",
768 _verify_forwarded_allow, // may have forwarded references
769 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
770 _verify_cset_forwarded, // allow forwarded references to cset
771 _verify_liveness_disable, // no reliable liveness data
772 _verify_regions_notrash, // no trash regions
773 _verify_gcstate_forwarded // there are forwarded objects
774 );
775 } else {
776 verify_at_safepoint(
777 "Before Mark",
778 _verify_forwarded_none, // UR should have fixed up
779 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
780 _verify_cset_none, // UR should have fixed this
781 _verify_liveness_disable, // no reliable liveness data
782 _verify_regions_notrash, // no trash regions
783 _verify_gcstate_stable // there are no forwarded objects
784 );
785 }
786 }
787
788 void ShenandoahVerifier::verify_after_concmark() {
789 verify_at_safepoint(
790 "After Mark",
791 _verify_forwarded_none, // no forwarded references
792 _verify_marked_complete, // bitmaps as precise as we can get
793 _verify_cset_none, // no references to cset anymore
794 _verify_liveness_complete, // liveness data must be complete here
795 _verify_regions_disable, // trash regions not yet recycled
796 _verify_gcstate_stable // mark should have stabilized the heap
797 );
798 }
799
800 void ShenandoahVerifier::verify_before_evacuation() {
801 verify_at_safepoint(
802 "Before Evacuation",
803 _verify_forwarded_none, // no forwarded references
804 _verify_marked_complete, // walk over marked objects too
805 _verify_cset_disable, // non-forwarded references to cset expected
806 _verify_liveness_complete, // liveness data must be complete here
807 _verify_regions_disable, // trash regions not yet recycled
808 _verify_gcstate_stable // mark should have stabilized the heap
809 );
810 }
811
812 void ShenandoahVerifier::verify_after_evacuation() {
813 verify_at_safepoint(
814 "After Evacuation",
815 _verify_forwarded_allow, // objects are still forwarded
816 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
817 _verify_cset_forwarded, // all cset refs are fully forwarded
818 _verify_liveness_disable, // no reliable liveness data anymore
819 _verify_regions_notrash, // trash regions have been recycled already
820 _verify_gcstate_forwarded // evacuation produced some forwarded objects
821 );
822 }
823
824 void ShenandoahVerifier::verify_before_updaterefs() {
825 verify_at_safepoint(
826 "Before Updating References",
827 _verify_forwarded_allow, // forwarded references allowed
828 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
829 _verify_cset_forwarded, // all cset refs are fully forwarded
830 _verify_liveness_disable, // no reliable liveness data anymore
831 _verify_regions_notrash, // trash regions have been recycled already
832 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
833 );
834 }
835
836 void ShenandoahVerifier::verify_after_updaterefs() {
837 verify_at_safepoint(
838 "After Updating References",
839 _verify_forwarded_none, // no forwarded references
840 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
841 _verify_cset_none, // no cset references, all updated
842 _verify_liveness_disable, // no reliable liveness data anymore
843 _verify_regions_nocset, // no cset regions, trash regions have appeared
844 _verify_gcstate_stable // update refs had cleaned up forwarded objects
845 );
846 }
847
848 void ShenandoahVerifier::verify_after_degenerated() {
849 verify_at_safepoint(
850 "After Degenerated GC",
851 _verify_forwarded_none, // all objects are non-forwarded
852 _verify_marked_complete, // all objects are marked in complete bitmap
853 _verify_cset_none, // no cset references
854 _verify_liveness_disable, // no reliable liveness data anymore
855 _verify_regions_notrash_nocset, // no trash, no cset
856 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
857 );
858 }
859
860 void ShenandoahVerifier::verify_before_traversal() {
861 verify_at_safepoint(
862 "Before Traversal",
863 _verify_forwarded_none, // cannot have forwarded objects
864 _verify_marked_disable, // bitmaps are not relevant before traversal
865 _verify_cset_none, // no cset references before traversal
866 _verify_liveness_disable, // no reliable liveness data anymore
867 _verify_regions_notrash_nocset, // no trash and no cset regions
868 _verify_gcstate_stable // nothing forwarded before traversal
869 );
870 }
871
872 void ShenandoahVerifier::verify_after_traversal() {
873 verify_at_safepoint(
874 "After Traversal",
875 _verify_forwarded_none, // cannot have forwarded objects
876 _verify_marked_complete, // should have complete marking after traversal
877 _verify_cset_none, // no cset references left after traversal
878 _verify_liveness_disable, // liveness data is not collected for new allocations
879 _verify_regions_nocset, // no cset regions, trash regions allowed
880 _verify_gcstate_stable // nothing forwarded after traversal
881 );
882 }
883
884 void ShenandoahVerifier::verify_before_fullgc() {
885 verify_at_safepoint(
886 "Before Full GC",
887 _verify_forwarded_allow, // can have forwarded objects
888 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
889 _verify_cset_disable, // cset might be foobared
890 _verify_liveness_disable, // no reliable liveness data anymore
891 _verify_regions_disable, // no reliable region data here
892 _verify_gcstate_disable // no reliable gcstate data
893 );
894 }
895
896 void ShenandoahVerifier::verify_after_fullgc() {
897 verify_at_safepoint(
898 "After Full GC",
899 _verify_forwarded_none, // all objects are non-forwarded
900 _verify_marked_complete, // all objects are marked in complete bitmap
901 _verify_cset_none, // no cset references
902 _verify_liveness_disable, // no reliable liveness data anymore
903 _verify_regions_notrash_nocset, // no trash, no cset
904 _verify_gcstate_stable // full gc cleaned up everything
905 );
906 }