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 "gc/shenandoah/brooksPointer.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahConnectionMatrix.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahHeap.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
33 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
34 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
35 #include "gc/shenandoah/shenandoahVerifier.hpp"
36 #include "memory/allocation.hpp"
37 #include "memory/iterator.inline.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 _stack(stack), _heap(ShenandoahHeap::heap()), _map(map), _ld(ld), _loc(NULL), _interior_loc(NULL),
59 _phase(phase), _options(options) {};
60
61 private:
62 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
63 if (!test) {
64 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
65 }
66 }
67
68 template <class T>
69 void do_oop_work(T* p) {
70 T o = RawAccess<>::oop_load(p);
71 if (!CompressedOops::is_null(o)) {
72 oop obj = CompressedOops::decode_not_null(o);
73
74 // Single threaded verification can use faster non-atomic stack and bitmap
75 // methods.
76 //
77 // For performance reasons, only fully verify non-marked field values.
78 // We are here when the host object for *p is already marked. If field value
79 // is marked already, then we have to verify the matrix connection between
80 // host object and field value, regardless.
81
82 HeapWord* addr = (HeapWord*) obj;
83 if (_map->parMark(addr)) {
84 verify_oop_at(p, obj);
85 _stack->push(ShenandoahVerifierTask(obj));
86 } else {
87 verify_matrix(p, obj);
88 }
89 }
90 }
91
92 void verify_oop(oop obj) {
93 // Perform consistency checks with gradually decreasing safety level. This guarantees
94 // that failure report would not try to touch something that was not yet verified to be
95 // safe to process.
96
97 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
98 "oop must be in heap");
99 check(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),
100 "oop must be aligned");
101
102 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
103 Klass* obj_klass = obj->klass_or_null();
104
105 // Verify that obj is not in dead space:
106 {
107 // Do this before touching obj->size()
108 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
109 "Object klass pointer should not be NULL");
110 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
111 "Object klass pointer must go to metaspace");
112
113 HeapWord *obj_addr = (HeapWord *) obj;
114 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
115 "Object start should be within the region");
116
117 if (!obj_reg->is_humongous()) {
118 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
119 "Object end should be within the region");
120 } else {
121 size_t humongous_start = obj_reg->region_number();
122 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
123 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
124 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
125 "Humongous object is in continuation that fits it");
126 }
127 }
128
129 // ------------ obj is safe at this point --------------
130
131 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
132 "Object should be in active region");
133
134 switch (_options._verify_liveness) {
135 case ShenandoahVerifier::_verify_liveness_disable:
136 // skip
137 break;
138 case ShenandoahVerifier::_verify_liveness_complete:
139 Atomic::add(obj->size() + BrooksPointer::word_size(), &_ld[obj_reg->region_number()]);
140 // fallthrough for fast failure for un-live regions:
141 case ShenandoahVerifier::_verify_liveness_conservative:
142 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
143 "Object must belong to region with live data");
144 break;
145 default:
146 assert(false, "Unhandled liveness verification");
147 }
148 }
149
150 oop fwd = (oop) BrooksPointer::get_raw_unchecked(obj);
151
152 ShenandoahHeapRegion* fwd_reg = NULL;
153
154 if (!oopDesc::unsafe_equals(obj, fwd)) {
155 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
156 "Forwardee must be in heap");
157 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
158 "Forwardee is set");
159 check(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),
160 "Forwardee must be aligned");
161
162 // Do this before touching fwd->size()
163 Klass* fwd_klass = fwd->klass_or_null();
164 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
165 "Forwardee klass pointer should not be NULL");
166 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
167 "Forwardee klass pointer must go to metaspace");
168 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
169 "Forwardee klass pointer must go to metaspace");
170
171 fwd_reg = _heap->heap_region_containing(fwd);
172
173 // Verify that forwardee is not in the dead space:
174 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
175 "Should have no humongous forwardees");
176
177 HeapWord *fwd_addr = (HeapWord *) fwd;
178 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
179 "Forwardee start should be within the region");
180 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
181 "Forwardee end should be within the region");
182
183 oop fwd2 = (oop) BrooksPointer::get_raw_unchecked(fwd);
184 check(ShenandoahAsserts::_safe_oop, obj, oopDesc::unsafe_equals(fwd, fwd2),
185 "Double forwarding");
186 } else {
187 fwd_reg = obj_reg;
188 }
189
190 // ------------ obj and fwd are safe at this point --------------
191
192 switch (_options._verify_marked) {
193 case ShenandoahVerifier::_verify_marked_disable:
194 // skip
195 break;
196 case ShenandoahVerifier::_verify_marked_next:
197 check(ShenandoahAsserts::_safe_all, obj, _heap->next_marking_context()->is_marked(obj),
198 "Must be marked in next bitmap");
199 break;
200 case ShenandoahVerifier::_verify_marked_complete:
201 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
202 "Must be marked in complete bitmap");
203 break;
204 default:
205 assert(false, "Unhandled mark verification");
206 }
207
208 switch (_options._verify_forwarded) {
209 case ShenandoahVerifier::_verify_forwarded_disable:
210 // skip
211 break;
212 case ShenandoahVerifier::_verify_forwarded_none: {
213 check(ShenandoahAsserts::_safe_all, obj, oopDesc::unsafe_equals(obj, fwd),
214 "Should not be forwarded");
215 break;
216 }
217 case ShenandoahVerifier::_verify_forwarded_allow: {
218 if (!oopDesc::unsafe_equals(obj, fwd)) {
219 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
220 "Forwardee should be in another region");
221 }
222 break;
223 }
224 default:
225 assert(false, "Unhandled forwarding verification");
226 }
227
228 switch (_options._verify_cset) {
229 case ShenandoahVerifier::_verify_cset_disable:
230 // skip
231 break;
232 case ShenandoahVerifier::_verify_cset_none:
233 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
234 "Should not have references to collection set");
235 break;
236 case ShenandoahVerifier::_verify_cset_forwarded:
237 if (_heap->in_collection_set(obj)) {
238 check(ShenandoahAsserts::_safe_all, obj, !oopDesc::unsafe_equals(obj, fwd),
239 "Object in collection set, should have forwardee");
240 }
241 break;
242 default:
243 assert(false, "Unhandled cset verification");
244 }
245
246 verify_matrix(_interior_loc, obj);
247 }
248
249 void verify_matrix(void* interior, oop obj) {
250 if (!UseShenandoahMatrix || !_heap->is_in(interior)) return;
251 switch (_options._verify_matrix) {
252 case ShenandoahVerifier::_verify_matrix_conservative: {
253 size_t from_idx = _heap->heap_region_index_containing(interior);
254 size_t to_idx = _heap->heap_region_index_containing(obj);
255 _interior_loc = interior;
256 check(ShenandoahAsserts::_safe_all, obj, _heap->connection_matrix()->is_connected(from_idx, to_idx),
257 "Must be connected");
258 _interior_loc = NULL;
259 break;
260 }
261 case ShenandoahVerifier::_verify_matrix_disable:
262 break;
263 default:
264 assert(false, "Unhandled matrix verification");
265 }
266 }
267
268 public:
269
270 /**
271 * Verify object with known interior reference.
272 * @param p interior reference where the object is referenced from; can be off-heap
273 * @param obj verified object
274 */
275 template <class T>
276 void verify_oop_at(T* p, oop obj) {
277 _interior_loc = p;
278 verify_oop(obj);
279 _interior_loc = NULL;
280 }
281
282 /**
283 * Verify object without known interior reference.
284 * Useful when picking up the object at known offset in heap,
285 * but without knowing what objects reference it.
286 * @param obj verified object
287 */
288 void verify_oop_standalone(oop obj) {
289 _interior_loc = NULL;
290 verify_oop(obj);
291 _interior_loc = NULL;
292 }
293
294 /**
295 * Verify oop fields from this object.
296 * @param obj host object for verified fields
297 */
298 void verify_oops_from(oop obj) {
299 _loc = obj;
300 obj->oop_iterate(this);
301 _loc = NULL;
302 }
303
304 virtual void do_oop(oop* p) { do_oop_work(p); }
305 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
306 };
307
308 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
309 private:
310 size_t _used, _committed, _garbage;
311 public:
312 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
313
314 bool heap_region_do(ShenandoahHeapRegion* r) {
315 _used += r->used();
316 _garbage += r->garbage();
317 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
318 return false;
319 }
320
321 size_t used() { return _used; }
322 size_t committed() { return _committed; }
323 size_t garbage() { return _garbage; }
324 };
325
326 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
327 private:
328 ShenandoahHeap* _heap;
329 const char* _phase;
330 ShenandoahVerifier::VerifyRegions _regions;
331 public:
332 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
333 _heap(ShenandoahHeap::heap()), _regions(regions), _phase(phase) {};
334
335 void print_failure(ShenandoahHeapRegion* r, const char* label) {
336 ResourceMark rm;
337
338 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
339
340 stringStream ss;
341 r->print_on(&ss);
342 msg.append("%s", ss.as_string());
343
344 report_vm_error(__FILE__, __LINE__, msg.buffer());
345 }
346
347 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
348 if (!test) {
349 print_failure(r, msg);
350 }
351 }
352
353 bool heap_region_do(ShenandoahHeapRegion* r) {
354 switch (_regions) {
355 case ShenandoahVerifier::_verify_regions_disable:
356 break;
357 case ShenandoahVerifier::_verify_regions_notrash:
358 verify(r, !r->is_trash(),
359 "Should not have trash regions");
360 break;
361 case ShenandoahVerifier::_verify_regions_nocset:
362 verify(r, !r->is_cset(),
363 "Should not have cset regions");
364 break;
365 case ShenandoahVerifier::_verify_regions_notrash_nocset:
366 verify(r, !r->is_trash(),
367 "Should not have trash regions");
368 verify(r, !r->is_cset(),
369 "Should not have cset regions");
370 break;
371 default:
372 ShouldNotReachHere();
373 }
374
375 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
376 "Capacity should match region size");
377
378 verify(r, r->bottom() <= _heap->complete_marking_context()->top_at_mark_start(r->region_number()),
379 "Region top should not be less than bottom");
380
381 verify(r, _heap->complete_marking_context()->top_at_mark_start(r->region_number()) <= r->top(),
382 "Complete TAMS should not be larger than top");
383
384 verify(r, r->get_live_data_bytes() <= r->capacity(),
385 "Live data cannot be larger than capacity");
386
387 verify(r, r->garbage() <= r->capacity(),
388 "Garbage cannot be larger than capacity");
389
390 verify(r, r->used() <= r->capacity(),
391 "Used cannot be larger than capacity");
392
393 verify(r, r->get_shared_allocs() <= r->capacity(),
394 "Shared alloc count should not be larger than capacity");
395
396 verify(r, r->get_tlab_allocs() <= r->capacity(),
397 "TLAB alloc count should not be larger than capacity");
398
399 verify(r, r->get_gclab_allocs() <= r->capacity(),
400 "GCLAB alloc count should not be larger than capacity");
401
402 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
403 "Accurate accounting: shared + TLAB + GCLAB = used");
404
405 verify(r, !r->is_empty() || !r->has_live(),
406 "Empty regions should not have live data");
407
408 verify(r, r->is_cset() == r->in_collection_set(),
409 "Transitional: region flags and collection set agree");
410
411 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
412 "Non-empty regions should have first seqnum set");
413
414 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
415 "Non-empty regions should have first seqnum set to either GC or mutator");
416
417 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
418 "Non-empty regions should have last seqnum set");
419
420 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
421 "Non-empty regions should have last seqnum set to either GC or mutator");
422
423 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
424 "First seqnum should not be greater than last timestamp");
425
426 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
427 "First mutator seqnum should not be greater than last seqnum");
428
429 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
430 "First GC seqnum should not be greater than last seqnum");
431
432 return false;
433 }
434 };
435
436 class ShenandoahVerifierReachableTask : public AbstractGangTask {
437 private:
438 const char* _label;
439 ShenandoahRootProcessor* _rp;
440 ShenandoahVerifier::VerifyOptions _options;
441 ShenandoahHeap* _heap;
442 ShenandoahLivenessData* _ld;
443 MarkBitMap* _bitmap;
444 volatile size_t _processed;
445
446 public:
447 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
448 ShenandoahLivenessData* ld,
449 ShenandoahRootProcessor* rp,
450 const char* label,
451 ShenandoahVerifier::VerifyOptions options) :
452 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
453 _heap(ShenandoahHeap::heap()), _rp(rp), _ld(ld), _bitmap(bitmap), _processed(0),
454 _label(label), _options(options) {};
455
456 size_t processed() {
457 return _processed;
458 }
459
460 virtual void work(uint worker_id) {
461 ResourceMark rm;
462 ShenandoahVerifierStack stack;
463
464 // On level 2, we need to only check the roots once.
465 // On level 3, we want to check the roots, and seed the local stack.
466 // It is a lesser evil to accept multiple root scans at level 3, because
467 // extended parallelism would buy us out.
468 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
469 || (ShenandoahVerifyLevel >= 3)) {
470 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
471 ShenandoahMessageBuffer("%s, Roots", _label),
472 _options);
473 _rp->process_all_roots_slow(&cl);
474 }
475
476 size_t processed = 0;
477
478 if (ShenandoahVerifyLevel >= 3) {
479 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
480 ShenandoahMessageBuffer("%s, Reachable", _label),
481 _options);
482 while (!stack.is_empty()) {
483 processed++;
484 ShenandoahVerifierTask task = stack.pop();
485 cl.verify_oops_from(task.obj());
486 }
487 }
488
489 Atomic::add(processed, &_processed);
490 }
491 };
492
493 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
494 private:
495 const char* _label;
496 ShenandoahVerifier::VerifyOptions _options;
497 ShenandoahHeap *_heap;
498 MarkBitMap* _bitmap;
499 ShenandoahLivenessData* _ld;
500 volatile size_t _claimed;
501 volatile size_t _processed;
502
503 public:
504 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
505 ShenandoahLivenessData* ld,
506 const char* label,
507 ShenandoahVerifier::VerifyOptions options) :
508 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
509 _heap(ShenandoahHeap::heap()), _ld(ld), _bitmap(bitmap), _claimed(0), _processed(0),
510 _label(label), _options(options) {};
511
512 size_t processed() {
513 return _processed;
514 }
515
516 virtual void work(uint worker_id) {
517 ShenandoahVerifierStack stack;
518 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
519 ShenandoahMessageBuffer("%s, Marked", _label),
520 _options);
521
522 while (true) {
523 size_t v = Atomic::add(1u, &_claimed) - 1;
524 if (v < _heap->num_regions()) {
525 ShenandoahHeapRegion* r = _heap->get_region(v);
526 if (!r->is_humongous() && !r->is_trash()) {
527 work_regular(r, stack, cl);
528 } else if (r->is_humongous_start()) {
529 work_humongous(r, stack, cl);
530 }
531 } else {
532 break;
533 }
534 }
535 }
536
537 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
538 size_t processed = 0;
539 HeapWord* obj = r->bottom() + BrooksPointer::word_size();
540 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
541 verify_and_follow(obj, stack, cl, &processed);
542 }
543 Atomic::add(processed, &_processed);
544 }
545
546 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
547 size_t processed = 0;
548 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
549 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r->region_number());
550
551 // Bitmaps, before TAMS
552 if (tams > r->bottom()) {
553 HeapWord* start = r->bottom() + BrooksPointer::word_size();
554 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
555
556 while (addr < tams) {
557 verify_and_follow(addr, stack, cl, &processed);
558 addr += BrooksPointer::word_size();
559 if (addr < tams) {
560 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
561 }
562 }
563 }
564
565 // Size-based, after TAMS
566 {
567 HeapWord* limit = r->top();
568 HeapWord* addr = tams + BrooksPointer::word_size();
569
570 while (addr < limit) {
571 verify_and_follow(addr, stack, cl, &processed);
572 addr += oop(addr)->size() + BrooksPointer::word_size();
573 }
574 }
575
576 Atomic::add(processed, &_processed);
577 }
578
579 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
580 if (!_bitmap->parMark(addr)) return;
581
582 // Verify the object itself:
583 oop obj = oop(addr);
584 cl.verify_oop_standalone(obj);
585
586 // Verify everything reachable from that object too, hopefully realizing
587 // everything was already marked, and never touching further:
588 cl.verify_oops_from(obj);
589 (*processed)++;
590
591 while (!stack.is_empty()) {
592 ShenandoahVerifierTask task = stack.pop();
593 cl.verify_oops_from(task.obj());
594 (*processed)++;
595 }
596 }
597 };
598
599 class VerifyThreadGCState : public ThreadClosure {
600 private:
601 const char* _label;
602 char _expected;
603
604 public:
605 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
606 void do_thread(Thread* t) {
607 char actual = ShenandoahThreadLocalData::gc_state(t);
608 if (actual != _expected) {
609 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
610 }
611 }
612 };
613
614
615 void ShenandoahVerifier::verify_at_safepoint(const char *label,
616 VerifyForwarded forwarded, VerifyMarked marked,
617 VerifyMatrix matrix, VerifyCollectionSet cset,
618 VerifyLiveness liveness, VerifyRegions regions,
619 VerifyGCState gcstate) {
620 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
621 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
622
623 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
624 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
625
626 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
627
628 // GC state checks
629 {
630 char expected = -1;
631 bool enabled;
632 switch (gcstate) {
633 case _verify_gcstate_disable:
634 enabled = false;
635 break;
636 case _verify_gcstate_forwarded:
637 enabled = true;
638 expected = ShenandoahHeap::HAS_FORWARDED;
639 break;
640 case _verify_gcstate_stable:
641 enabled = true;
642 expected = ShenandoahHeap::STABLE;
643 break;
644 default:
645 enabled = false;
646 assert(false, "Unhandled gc-state verification");
647 }
648
649 if (enabled) {
650 char actual = _heap->gc_state();
651 if (actual != expected) {
652 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
653 }
654
655 VerifyThreadGCState vtgcs(label, expected);
656 Threads::java_threads_do(&vtgcs);
657 }
658 }
659
660 // Heap size checks
661 {
662 ShenandoahHeapLocker lock(_heap->lock());
663
664 ShenandoahCalculateRegionStatsClosure cl;
665 _heap->heap_region_iterate(&cl);
666 size_t heap_used = _heap->used();
667 guarantee(cl.used() == heap_used,
668 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
669 label, heap_used/K, cl.used()/K);
670
671 size_t heap_committed = _heap->committed();
672 guarantee(cl.committed() == heap_committed,
673 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
674 label, heap_committed/K, cl.committed()/K);
675 }
676
677 // Internal heap region checks
678 if (ShenandoahVerifyLevel >= 1) {
679 ShenandoahVerifyHeapRegionClosure cl(label, regions);
680 _heap->heap_region_iterate(&cl,
681 /* skip_cset = */ false,
682 /* skip_humongous_cont = */ false);
683 }
684
685 OrderAccess::fence();
686 _heap->make_parsable(false);
687
688 // Allocate temporary bitmap for storing marking wavefront:
689 MemRegion mr = MemRegion(_verification_bit_map->startWord(), _verification_bit_map->endWord());
690 _verification_bit_map->clear_range_large(mr);
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, matrix, 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 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
703 ShenandoahPhaseTimings::_num_phases); // no need for stats
704
705 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
706 _heap->workers()->run_task(&task);
707 count_reachable = task.processed();
708 }
709
710 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
711 // not the application, can see during the region scans. There is no reason to process the objects
712 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
713 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
714 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
715 // version
716
717 size_t count_marked = 0;
718 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_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_next || 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()->region_number()]);
738 if (start_live > 0) {
739 verf_live = (juint)(r->used() / HeapWordSize);
740 }
741 } else {
742 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
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_matrix_disable, // matrix can be inconsistent here
768 _verify_cset_disable, // cset may be inconsistent
769 _verify_liveness_disable, // no reliable liveness data
770 _verify_regions_disable, // no reliable region data
771 _verify_gcstate_disable // no data about gcstate
772 );
773 }
774
775 void ShenandoahVerifier::verify_before_concmark() {
776 if (_heap->has_forwarded_objects()) {
777 verify_at_safepoint(
778 "Before Mark",
779 _verify_forwarded_allow, // may have forwarded references
780 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
781 _verify_matrix_disable, // matrix is foobared
782 _verify_cset_forwarded, // allow forwarded references to cset
783 _verify_liveness_disable, // no reliable liveness data
784 _verify_regions_notrash, // no trash regions
785 _verify_gcstate_forwarded // there are forwarded objects
786 );
787 } else {
788 verify_at_safepoint(
789 "Before Mark",
790 _verify_forwarded_none, // UR should have fixed up
791 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
792 _verify_matrix_conservative, // UR should have fixed matrix
793 _verify_cset_none, // UR should have fixed this
794 _verify_liveness_disable, // no reliable liveness data
795 _verify_regions_notrash, // no trash regions
796 _verify_gcstate_stable // there are no forwarded objects
797 );
798 }
799 }
800
801 void ShenandoahVerifier::verify_after_concmark() {
802 verify_at_safepoint(
803 "After Mark",
804 _verify_forwarded_none, // no forwarded references
805 _verify_marked_complete, // bitmaps as precise as we can get
806 _verify_matrix_disable, // matrix might be foobared
807 _verify_cset_none, // no references to cset anymore
808 _verify_liveness_complete, // liveness data must be complete here
809 _verify_regions_disable, // trash regions not yet recycled
810 _verify_gcstate_stable // mark should have stabilized the heap
811 );
812 }
813
814 void ShenandoahVerifier::verify_before_evacuation() {
815 // Evacuation is always preceded by mark, but we want to have a sanity check after
816 // selecting the collection set, and (immediate) regions recycling
817 verify_at_safepoint(
818 "Before Evacuation",
819 _verify_forwarded_none, // no forwarded references
820 _verify_marked_complete, // walk over marked objects too
821 _verify_matrix_disable, // skip, verified after mark
822 _verify_cset_disable, // skip, verified after mark
823 _verify_liveness_disable, // skip, verified after mark
824 _verify_regions_disable, // trash regions not yet recycled
825 _verify_gcstate_stable // mark should have stabilized the heap
826 );
827 }
828
829 void ShenandoahVerifier::verify_after_evacuation() {
830 verify_at_safepoint(
831 "After Evacuation",
832 _verify_forwarded_allow, // objects are still forwarded
833 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
834 _verify_matrix_disable, // matrix is inconsistent here
835 _verify_cset_forwarded, // all cset refs are fully forwarded
836 _verify_liveness_disable, // no reliable liveness data anymore
837 _verify_regions_notrash, // trash regions have been recycled already
838 _verify_gcstate_forwarded // evacuation produced some forwarded objects
839 );
840 }
841
842 void ShenandoahVerifier::verify_before_updaterefs() {
843 verify_at_safepoint(
844 "Before Updating References",
845 _verify_forwarded_allow, // forwarded references allowed
846 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
847 _verify_matrix_disable, // matrix is inconsistent here
848 _verify_cset_forwarded, // all cset refs are fully forwarded
849 _verify_liveness_disable, // no reliable liveness data anymore
850 _verify_regions_notrash, // trash regions have been recycled already
851 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
852 );
853 }
854
855 void ShenandoahVerifier::verify_after_updaterefs() {
856 verify_at_safepoint(
857 "After Updating References",
858 _verify_forwarded_none, // no forwarded references
859 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
860 _verify_matrix_conservative, // matrix is conservatively consistent
861 _verify_cset_none, // no cset references, all updated
862 _verify_liveness_disable, // no reliable liveness data anymore
863 _verify_regions_nocset, // no cset regions, trash regions have appeared
864 _verify_gcstate_stable // update refs had cleaned up forwarded objects
865 );
866 }
867
868 void ShenandoahVerifier::verify_after_degenerated() {
869 verify_at_safepoint(
870 "After Degenerated GC",
871 _verify_forwarded_none, // all objects are non-forwarded
872 _verify_marked_complete, // all objects are marked in complete bitmap
873 _verify_matrix_conservative, // matrix is conservatively consistent
874 _verify_cset_none, // no cset references
875 _verify_liveness_disable, // no reliable liveness data anymore
876 _verify_regions_notrash_nocset, // no trash, no cset
877 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
878 );
879 }
880
881 void ShenandoahVerifier::verify_before_traversal() {
882 verify_at_safepoint(
883 "Before Traversal",
884 _verify_forwarded_none, // cannot have forwarded objects
885 _verify_marked_disable, // bitmaps are not relevant before traversal
886 _verify_matrix_disable, // matrix is not used in traversal
887 _verify_cset_none, // no cset references before traversal
888 _verify_liveness_disable, // no reliable liveness data anymore
889 _verify_regions_notrash_nocset, // no trash and no cset regions
890 _verify_gcstate_stable // nothing forwarded before traversal
891 );
892 }
893
894 void ShenandoahVerifier::verify_after_traversal() {
895 verify_at_safepoint(
896 "After Traversal",
897 _verify_forwarded_none, // cannot have forwarded objects
898 _verify_marked_disable, // We only have partial marking info after traversal
899 _verify_matrix_disable, // matrix is conservatively consistent
900 _verify_cset_none, // no cset references left after traversal
901 _verify_liveness_disable, // liveness data is not collected for new allocations
902 _verify_regions_nocset, // no cset regions, trash regions allowed
903 _verify_gcstate_stable // nothing forwarded after traversal
904 );
905 }
906
907 void ShenandoahVerifier::verify_before_fullgc() {
908 verify_at_safepoint(
909 "Before Full GC",
910 _verify_forwarded_allow, // can have forwarded objects
911 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
912 _verify_matrix_disable, // matrix might be foobared
913 _verify_cset_disable, // cset might be foobared
914 _verify_liveness_disable, // no reliable liveness data anymore
915 _verify_regions_disable, // no reliable region data here
916 _verify_gcstate_disable // no reliable gcstate data
917 );
918 }
919
920 void ShenandoahVerifier::verify_after_fullgc() {
921 verify_at_safepoint(
922 "After Full GC",
923 _verify_forwarded_none, // all objects are non-forwarded
924 _verify_marked_complete, // all objects are marked in complete bitmap
925 _verify_matrix_conservative, // matrix is conservatively consistent
926 _verify_cset_none, // no cset references
927 _verify_liveness_disable, // no reliable liveness data anymore
928 _verify_regions_notrash_nocset, // no trash, no cset
929 _verify_gcstate_stable // full gc cleaned up everything
930 );
931 }
932