1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/tlab_globals.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahGeneration.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
33 #include "gc/shenandoah/shenandoahOldGeneration.hpp"
34 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
35 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
36 #include "gc/shenandoah/shenandoahUtils.hpp"
37 #include "gc/shenandoah/shenandoahVerifier.hpp"
38 #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
39 #include "memory/allocation.hpp"
40 #include "memory/iterator.inline.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "oops/compressedOops.inline.hpp"
43 #include "runtime/atomic.hpp"
44 #include "runtime/orderAccess.hpp"
45 #include "runtime/threads.hpp"
46 #include "utilities/align.hpp"
47
48 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
49 #ifdef verify_oop
50 #undef verify_oop
51 #endif
52
53 static bool is_instance_ref_klass(Klass* k) {
54 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
55 }
56
57 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
58 public:
59 virtual bool discover_reference(oop obj, ReferenceType type) {
60 return true;
61 }
62 };
63
64 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
65 private:
66 const char* _phase;
67 ShenandoahVerifier::VerifyOptions _options;
68 ShenandoahVerifierStack* _stack;
69 ShenandoahHeap* _heap;
70 MarkBitMap* _map;
71 ShenandoahLivenessData* _ld;
72 void* _interior_loc;
73 oop _loc;
74 ShenandoahGeneration* _generation;
75
76 public:
77 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
78 const char* phase, ShenandoahVerifier::VerifyOptions options) :
79 _phase(phase),
80 _options(options),
81 _stack(stack),
82 _heap(ShenandoahHeap::heap()),
83 _map(map),
84 _ld(ld),
85 _interior_loc(NULL),
86 _loc(NULL),
87 _generation(NULL) {
88 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
89 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
90 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
91 }
92
93 if (_heap->mode()->is_generational()) {
94 _generation = _heap->active_generation();
95 assert(_generation != NULL, "Expected active generation in this mode");
96 }
97 }
98
99 private:
100 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
101 if (!test) {
102 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
103 }
104 }
105
106 template <class T>
107 void do_oop_work(T* p) {
108 T o = RawAccess<>::oop_load(p);
109 if (!CompressedOops::is_null(o)) {
110 oop obj = CompressedOops::decode_not_null(o);
111 if (is_instance_ref_klass(obj->klass())) {
112 obj = ShenandoahForwarding::get_forwardee(obj);
113 }
114 // Single threaded verification can use faster non-atomic stack and bitmap
115 // methods.
116 //
117 // For performance reasons, only fully verify non-marked field values.
118 // We are here when the host object for *p is already marked.
119
120 if ( in_generation(obj) && _map->par_mark(obj)) {
121 verify_oop_at(p, obj);
122 _stack->push(ShenandoahVerifierTask(obj));
123 }
124 }
125 }
126
127 bool in_generation(oop obj) {
128 if (_generation == NULL) {
129 return true;
130 }
131
132 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
133 return _generation->contains(region);
134 }
135
136 void verify_oop(oop obj) {
137 // Perform consistency checks with gradually decreasing safety level. This guarantees
138 // that failure report would not try to touch something that was not yet verified to be
139 // safe to process.
140
141 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
142 "oop must be in heap");
143 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
144 "oop must be aligned");
145
146 ShenandoahHeapRegion* obj_reg = _heap->heap_region_containing(obj);
147 Klass* obj_klass = obj->klass_or_null();
148
149 // Verify that obj is not in dead space:
150 {
151 // Do this before touching obj->size()
152 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
153 "Object klass pointer should not be NULL");
154 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
155 "Object klass pointer must go to metaspace");
156
157 HeapWord* obj_addr = cast_from_oop<HeapWord*>(obj);
158 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
159 "Object start should be within the region");
160
161 if (!obj_reg->is_humongous()) {
162 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
163 "Object end should be within the region");
164 } else {
165 size_t humongous_start = obj_reg->index();
166 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
167 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
168 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
169 "Humongous object is in continuation that fits it");
170 }
171 }
172
173 // ------------ obj is safe at this point --------------
174
175 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
176 "Object should be in active region");
177
178 switch (_options._verify_liveness) {
179 case ShenandoahVerifier::_verify_liveness_disable:
180 // skip
181 break;
182 case ShenandoahVerifier::_verify_liveness_complete:
183 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
184 // fallthrough for fast failure for un-live regions:
185 case ShenandoahVerifier::_verify_liveness_conservative:
186 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
187 (obj_reg->is_old() && ShenandoahHeap::heap()->is_gc_generation_young()),
188 "Object must belong to region with live data");
189 break;
190 default:
191 assert(false, "Unhandled liveness verification");
192 }
193 }
194
195 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
196
197 ShenandoahHeapRegion* fwd_reg = NULL;
198
199 if (obj != fwd) {
200 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
201 "Forwardee must be in heap");
202 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
203 "Forwardee is set");
204 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
205 "Forwardee must be aligned");
206
207 // Do this before touching fwd->size()
208 Klass* fwd_klass = fwd->klass_or_null();
209 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
210 "Forwardee klass pointer should not be NULL");
211 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
212 "Forwardee klass pointer must go to metaspace");
213 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
214 "Forwardee klass pointer must go to metaspace");
215
216 fwd_reg = _heap->heap_region_containing(fwd);
217
218 // Verify that forwardee is not in the dead space:
219 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
220 "Should have no humongous forwardees");
221
222 HeapWord* fwd_addr = cast_from_oop<HeapWord* >(fwd);
223 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
224 "Forwardee start should be within the region");
225 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
226 "Forwardee end should be within the region");
227
228 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
229 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
230 "Double forwarding");
231 } else {
232 fwd_reg = obj_reg;
233 }
234
235 // ------------ obj and fwd are safe at this point --------------
236 // We allow for marked or old here for two reasons:
237 // 1. If this is a young collect, old objects wouldn't be marked. We've
238 // recently change the verifier traversal to only follow young objects
239 // during a young collect so this _shouldn't_ be necessary.
240 // 2. At present, we do not clear dead objects from the remembered set.
241 // Everything in the remembered set is old (ipso facto), so allowing for
242 // 'marked_or_old' covers the case of stale objects in rset.
243 // TODO: Just use 'is_marked' here.
244 switch (_options._verify_marked) {
245 case ShenandoahVerifier::_verify_marked_disable:
246 // skip
247 break;
248 case ShenandoahVerifier::_verify_marked_incomplete:
249 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked_or_old(obj),
250 "Must be marked in incomplete bitmap");
251 break;
252 case ShenandoahVerifier::_verify_marked_complete:
253 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
254 "Must be marked in complete bitmap");
255 break;
256 case ShenandoahVerifier::_verify_marked_complete_except_references:
257 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
258 "Must be marked in complete bitmap, except j.l.r.Reference referents");
259 break;
260 default:
261 assert(false, "Unhandled mark verification");
262 }
263
264 switch (_options._verify_forwarded) {
265 case ShenandoahVerifier::_verify_forwarded_disable:
266 // skip
267 break;
268 case ShenandoahVerifier::_verify_forwarded_none: {
269 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
270 "Should not be forwarded");
271 break;
272 }
273 case ShenandoahVerifier::_verify_forwarded_allow: {
274 if (obj != fwd) {
275 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
276 "Forwardee should be in another region");
277 }
278 break;
279 }
280 default:
281 assert(false, "Unhandled forwarding verification");
282 }
283
284 switch (_options._verify_cset) {
285 case ShenandoahVerifier::_verify_cset_disable:
286 // skip
287 break;
288 case ShenandoahVerifier::_verify_cset_none:
289 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
290 "Should not have references to collection set");
291 break;
292 case ShenandoahVerifier::_verify_cset_forwarded:
293 if (_heap->in_collection_set(obj)) {
294 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
295 "Object in collection set, should have forwardee");
296 }
297 break;
298 default:
299 assert(false, "Unhandled cset verification");
300 }
301
302 }
303
304 public:
305 /**
306 * Verify object with known interior reference.
307 * @param p interior reference where the object is referenced from; can be off-heap
308 * @param obj verified object
309 */
310 template <class T>
311 void verify_oop_at(T* p, oop obj) {
312 _interior_loc = p;
313 verify_oop(obj);
314 _interior_loc = NULL;
315 }
316
317 /**
318 * Verify object without known interior reference.
319 * Useful when picking up the object at known offset in heap,
320 * but without knowing what objects reference it.
321 * @param obj verified object
322 */
323 void verify_oop_standalone(oop obj) {
324 _interior_loc = NULL;
325 verify_oop(obj);
326 _interior_loc = NULL;
327 }
328
329 /**
330 * Verify oop fields from this object.
331 * @param obj host object for verified fields
332 */
333 void verify_oops_from(oop obj) {
334 _loc = obj;
335 obj->oop_iterate(this);
336 _loc = NULL;
337 }
338
339 virtual void do_oop(oop* p) { do_oop_work(p); }
340 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
341 };
342
343 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
344 private:
345 size_t _used, _committed, _garbage;
346 public:
347 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
348
349 void heap_region_do(ShenandoahHeapRegion* r) {
350 _used += r->used();
351 log_debug(gc)("ShenandoahCalculatRegionStatsClosure added " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
352 r->used(), r->is_humongous()? "humongous": "regular", r->index(), _used);
353 _garbage += r->garbage();
354 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
355 }
356
357 size_t used() { return _used; }
358 size_t committed() { return _committed; }
359 size_t garbage() { return _garbage; }
360 };
361
362 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
363 public:
364 ShenandoahCalculateRegionStatsClosure old;
365 ShenandoahCalculateRegionStatsClosure young;
366 ShenandoahCalculateRegionStatsClosure global;
367
368 void heap_region_do(ShenandoahHeapRegion* r) override {
369 switch (r->affiliation()) {
370 default:
371 ShouldNotReachHere();
372 return;
373 case FREE: return;
374 case YOUNG_GENERATION:
375 young.heap_region_do(r);
376 break;
377 case OLD_GENERATION:
378 old.heap_region_do(r);
379 break;
380 }
381 global.heap_region_do(r);
382 }
383
384 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
385 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
386 generation->name(),
387 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
388 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
389 }
390
391 static void validate_usage(const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
392 size_t generation_used = generation->used();
393 guarantee(stats.used() == generation_used,
394 "%s: generation (%s) used size must be consistent: generation-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
395 label, generation->name(),
396 byte_size_in_proper_unit(generation_used), proper_unit_for_byte_size(generation_used),
397 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
398 }
399 };
400
401 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
402 private:
403 ShenandoahHeap* _heap;
404 const char* _phase;
405 ShenandoahVerifier::VerifyRegions _regions;
406 public:
407 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
408 _heap(ShenandoahHeap::heap()),
409 _phase(phase),
410 _regions(regions) {};
411
412 void print_failure(ShenandoahHeapRegion* r, const char* label) {
413 ResourceMark rm;
414
415 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
416
417 stringStream ss;
418 r->print_on(&ss);
419 msg.append("%s", ss.as_string());
420
421 report_vm_error(__FILE__, __LINE__, msg.buffer());
422 }
423
424 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
425 if (!test) {
426 print_failure(r, msg);
427 }
428 }
429
430 void heap_region_do(ShenandoahHeapRegion* r) {
431 switch (_regions) {
432 case ShenandoahVerifier::_verify_regions_disable:
433 break;
434 case ShenandoahVerifier::_verify_regions_notrash:
435 verify(r, !r->is_trash(),
436 "Should not have trash regions");
437 break;
438 case ShenandoahVerifier::_verify_regions_nocset:
439 verify(r, !r->is_cset(),
440 "Should not have cset regions");
441 break;
442 case ShenandoahVerifier::_verify_regions_notrash_nocset:
443 verify(r, !r->is_trash(),
444 "Should not have trash regions");
445 verify(r, !r->is_cset(),
446 "Should not have cset regions");
447 break;
448 default:
449 ShouldNotReachHere();
450 }
451
452 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
453 "Capacity should match region size");
454
455 verify(r, r->bottom() <= r->top(),
456 "Region top should not be less than bottom");
457
458 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
459 "Region TAMS should not be less than bottom");
460
461 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
462 "Complete TAMS should not be larger than top");
463
464 verify(r, r->get_live_data_bytes() <= r->capacity(),
465 "Live data cannot be larger than capacity");
466
467 verify(r, r->garbage() <= r->capacity(),
468 "Garbage cannot be larger than capacity");
469
470 verify(r, r->used() <= r->capacity(),
471 "Used cannot be larger than capacity");
472
473 verify(r, r->get_shared_allocs() <= r->capacity(),
474 "Shared alloc count should not be larger than capacity");
475
476 verify(r, r->get_tlab_allocs() <= r->capacity(),
477 "TLAB alloc count should not be larger than capacity");
478
479 verify(r, r->get_gclab_allocs() <= r->capacity(),
480 "GCLAB alloc count should not be larger than capacity");
481
482 verify(r, r->get_plab_allocs() <= r->capacity(),
483 "PLAB alloc count should not be larger than capacity");
484
485 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
486 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
487
488 verify(r, !r->is_empty() || !r->has_live(),
489 "Empty regions should not have live data");
490
491 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
492 "Transitional: region flags and collection set agree");
493 }
494 };
495
496 class ShenandoahVerifierReachableTask : public WorkerTask {
497 private:
498 const char* _label;
499 ShenandoahVerifier::VerifyOptions _options;
500 ShenandoahHeap* _heap;
501 ShenandoahLivenessData* _ld;
502 MarkBitMap* _bitmap;
503 volatile size_t _processed;
504
505 public:
506 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
507 ShenandoahLivenessData* ld,
508 const char* label,
509 ShenandoahVerifier::VerifyOptions options) :
510 WorkerTask("Shenandoah Verifier Reachable Objects"),
511 _label(label),
512 _options(options),
513 _heap(ShenandoahHeap::heap()),
514 _ld(ld),
515 _bitmap(bitmap),
516 _processed(0) {};
517
518 size_t processed() {
519 return _processed;
520 }
521
522 virtual void work(uint worker_id) {
523 ResourceMark rm;
524 ShenandoahVerifierStack stack;
525
526 // On level 2, we need to only check the roots once.
527 // On level 3, we want to check the roots, and seed the local stack.
528 // It is a lesser evil to accept multiple root scans at level 3, because
529 // extended parallelism would buy us out.
530 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
531 || (ShenandoahVerifyLevel >= 3)) {
532 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
533 ShenandoahMessageBuffer("%s, Roots", _label),
534 _options);
535 if (_heap->unload_classes()) {
536 ShenandoahRootVerifier::strong_roots_do(&cl);
537 } else {
538 ShenandoahRootVerifier::roots_do(&cl);
539 }
540 }
541
542 size_t processed = 0;
543
544 if (ShenandoahVerifyLevel >= 3) {
545 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
546 ShenandoahMessageBuffer("%s, Reachable", _label),
547 _options);
548 while (!stack.is_empty()) {
549 processed++;
550 ShenandoahVerifierTask task = stack.pop();
551 cl.verify_oops_from(task.obj());
552 }
553 }
554
555 Atomic::add(&_processed, processed, memory_order_relaxed);
556 }
557 };
558
559 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
560 private:
561 const char* _label;
562 ShenandoahVerifier::VerifyOptions _options;
563 ShenandoahHeap* _heap;
564 MarkBitMap* _bitmap;
565 ShenandoahLivenessData* _ld;
566 volatile size_t _claimed;
567 volatile size_t _processed;
568 ShenandoahGeneration* _generation;
569
570 public:
571 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
572 ShenandoahLivenessData* ld,
573 const char* label,
574 ShenandoahVerifier::VerifyOptions options) :
575 WorkerTask("Shenandoah Verifier Marked Objects"),
576 _label(label),
577 _options(options),
578 _heap(ShenandoahHeap::heap()),
579 _bitmap(bitmap),
580 _ld(ld),
581 _claimed(0),
582 _processed(0),
583 _generation(NULL) {
584 if (_heap->mode()->is_generational()) {
585 _generation = _heap->active_generation();
586 assert(_generation != NULL, "Expected active generation in this mode.");
587 }
588 };
589
590 size_t processed() {
591 return Atomic::load(&_processed);
592 }
593
594 virtual void work(uint worker_id) {
595 ShenandoahVerifierStack stack;
596 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
597 ShenandoahMessageBuffer("%s, Marked", _label),
598 _options);
599
600 while (true) {
601 size_t v = Atomic::fetch_and_add(&_claimed, 1u, memory_order_relaxed);
602 if (v < _heap->num_regions()) {
603 ShenandoahHeapRegion* r = _heap->get_region(v);
604 if (!in_generation(r)) {
605 continue;
606 }
607
608 if (!r->is_humongous() && !r->is_trash()) {
609 work_regular(r, stack, cl);
610 } else if (r->is_humongous_start()) {
611 work_humongous(r, stack, cl);
612 }
613 } else {
614 break;
615 }
616 }
617 }
618
619 bool in_generation(ShenandoahHeapRegion* r) {
620 return _generation == NULL || _generation->contains(r);
621 }
622
623 virtual void work_humongous(ShenandoahHeapRegion* r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
624 size_t processed = 0;
625 HeapWord* obj = r->bottom();
626 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
627 verify_and_follow(obj, stack, cl, &processed);
628 }
629 Atomic::add(&_processed, processed, memory_order_relaxed);
630 }
631
632 virtual void work_regular(ShenandoahHeapRegion* r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
633 size_t processed = 0;
634 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
635 HeapWord* tams = ctx->top_at_mark_start(r);
636
637 // Bitmaps, before TAMS
638 if (tams > r->bottom()) {
639 HeapWord* start = r->bottom();
640 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
641
642 while (addr < tams) {
643 verify_and_follow(addr, stack, cl, &processed);
644 addr += 1;
645 if (addr < tams) {
646 addr = ctx->get_next_marked_addr(addr, tams);
647 }
648 }
649 }
650
651 // Size-based, after TAMS
652 {
653 HeapWord* limit = r->top();
654 HeapWord* addr = tams;
655
656 while (addr < limit) {
657 verify_and_follow(addr, stack, cl, &processed);
658 addr += cast_to_oop(addr)->size();
659 }
660 }
661
662 Atomic::add(&_processed, processed, memory_order_relaxed);
663 }
664
665 void verify_and_follow(HeapWord* addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t* processed) {
666 if (!_bitmap->par_mark(addr)) return;
667
668 // Verify the object itself:
669 oop obj = cast_to_oop(addr);
670 cl.verify_oop_standalone(obj);
671
672 // Verify everything reachable from that object too, hopefully realizing
673 // everything was already marked, and never touching further:
674 if (!is_instance_ref_klass(obj->klass())) {
675 cl.verify_oops_from(obj);
676 (*processed)++;
677 }
678 while (!stack.is_empty()) {
679 ShenandoahVerifierTask task = stack.pop();
680 cl.verify_oops_from(task.obj());
681 (*processed)++;
682 }
683 }
684 };
685
686 class VerifyThreadGCState : public ThreadClosure {
687 private:
688 const char* const _label;
689 char const _expected;
690
691 public:
692 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
693 void do_thread(Thread* t) {
694 char actual = ShenandoahThreadLocalData::gc_state(t);
695 if (actual != _expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
696 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
697 }
698 }
699 };
700
701 void ShenandoahVerifier::verify_at_safepoint(const char* label,
702 VerifyRememberedSet remembered,
703 VerifyForwarded forwarded, VerifyMarked marked,
704 VerifyCollectionSet cset,
705 VerifyLiveness liveness, VerifyRegions regions,
706 VerifyGCState gcstate) {
707 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
708 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
709
710 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
711 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
712
713 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
714
715 // GC state checks
716 {
717 char expected = -1;
718 bool enabled;
719 switch (gcstate) {
720 case _verify_gcstate_disable:
721 enabled = false;
722 break;
723 case _verify_gcstate_forwarded:
724 enabled = true;
725 expected = ShenandoahHeap::HAS_FORWARDED;
726 break;
727 case _verify_gcstate_evacuation:
728 enabled = true;
729 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
730 if (!_heap->is_stw_gc_in_progress()) {
731 // Only concurrent GC sets this.
732 expected |= ShenandoahHeap::WEAK_ROOTS;
733 }
734 break;
735 case _verify_gcstate_updating:
736 enabled = true;
737 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
738 break;
739 case _verify_gcstate_stable:
740 enabled = true;
741 expected = ShenandoahHeap::STABLE;
742 break;
743 case _verify_gcstate_stable_weakroots:
744 enabled = true;
745 expected = ShenandoahHeap::STABLE;
746 if (!_heap->is_stw_gc_in_progress()) {
747 // Only concurrent GC sets this.
748 expected |= ShenandoahHeap::WEAK_ROOTS;
749 }
750 break;
751 default:
752 enabled = false;
753 assert(false, "Unhandled gc-state verification");
754 }
755
756 if (enabled) {
757 char actual = _heap->gc_state();
758 // Old generation marking is allowed in all states.
759 if (actual != expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
760 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
761 }
762
763 VerifyThreadGCState vtgcs(label, expected);
764 Threads::java_threads_do(&vtgcs);
765 }
766 }
767
768 // Deactivate barriers temporarily: Verifier wants plain heap accesses
769 ShenandoahGCStateResetter resetter;
770
771 // Heap size checks
772 {
773 ShenandoahHeapLocker lock(_heap->lock());
774
775 ShenandoahCalculateRegionStatsClosure cl;
776 _heap->heap_region_iterate(&cl);
777
778 size_t heap_used = _heap->used();
779
780 guarantee(cl.used() == heap_used,
781 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
782 label,
783 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
784 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
785
786 size_t heap_committed = _heap->committed();
787 guarantee(cl.committed() == heap_committed,
788 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
789 label,
790 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
791 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
792 }
793
794 log_debug(gc)("Safepoint verification finished heap usage verification");
795
796 ShenandoahGeneration* generation;
797 if (_heap->mode()->is_generational()) {
798 generation = _heap->active_generation();
799 guarantee(generation != NULL, "Need to know which generation to verify.");
800 } else {
801 generation = NULL;
802 }
803
804 if (generation != NULL) {
805 ShenandoahHeapLocker lock(_heap->lock());
806
807 if (remembered == _verify_remembered_for_marking) {
808 log_debug(gc)("Safepoint verification of remembered set at mark");
809 } else if (remembered == _verify_remembered_for_updating_references) {
810 log_debug(gc)("Safepoint verification of remembered set at update ref");
811 } else if (remembered == _verify_remembered_after_full_gc) {
812 log_debug(gc)("Safepoint verification of remembered set after full gc");
813 }
814
815 if (remembered == _verify_remembered_for_marking) {
816 _heap->verify_rem_set_at_mark();
817 } else if (remembered == _verify_remembered_for_updating_references) {
818 _heap->verify_rem_set_at_update_ref();
819 } else if (remembered == _verify_remembered_after_full_gc) {
820 _heap->verify_rem_set_after_full_gc();
821 }
822
823 ShenandoahGenerationStatsClosure cl;
824 _heap->heap_region_iterate(&cl);
825
826 if (LogTarget(Debug, gc)::is_enabled()) {
827 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
828 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
829 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
830 }
831
832 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->old_generation(), cl.old);
833 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->young_generation(), cl.young);
834 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->global_generation(), cl.global);
835 }
836
837 log_debug(gc)("Safepoint verification finished remembered set verification");
838
839 // Internal heap region checks
840 if (ShenandoahVerifyLevel >= 1) {
841 ShenandoahVerifyHeapRegionClosure cl(label, regions);
842 if (generation != NULL) {
843 generation->heap_region_iterate(&cl);
844 } else {
845 _heap->heap_region_iterate(&cl);
846 }
847 }
848
849 log_debug(gc)("Safepoint verification finished heap region closure verification");
850
851 OrderAccess::fence();
852
853 if (UseTLAB) {
854 _heap->labs_make_parsable();
855 }
856
857 // Allocate temporary bitmap for storing marking wavefront:
858 _verification_bit_map->clear();
859
860 // Allocate temporary array for storing liveness data
861 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
862 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
863
864 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
865
866 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
867 // This verifies what application can see, since it only cares about reachable objects.
868 size_t count_reachable = 0;
869 if (ShenandoahVerifyLevel >= 2) {
870 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
871 _heap->workers()->run_task(&task);
872 count_reachable = task.processed();
873 }
874
875 log_debug(gc)("Safepoint verification finished getting initial reachable set");
876
877 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
878 // not the application, can see during the region scans. There is no reason to process the objects
879 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
880 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
881 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
882 // version
883
884 size_t count_marked = 0;
885 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
886 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
887 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
888 _heap->workers()->run_task(&task);
889 count_marked = task.processed();
890 } else {
891 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
892 }
893
894 log_debug(gc)("Safepoint verification finished walking marked objects");
895
896 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
897 // marked objects.
898
899 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
900 for (size_t i = 0; i < _heap->num_regions(); i++) {
901 ShenandoahHeapRegion* r = _heap->get_region(i);
902 if (generation != NULL && !generation->contains(r)) {
903 continue;
904 }
905
906 juint verf_live = 0;
907 if (r->is_humongous()) {
908 // For humongous objects, test if start region is marked live, and if so,
909 // all humongous regions in that chain have live data equal to their "used".
910 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
911 if (start_live > 0) {
912 verf_live = (juint)(r->used() / HeapWordSize);
913 }
914 } else {
915 verf_live = Atomic::load(&ld[r->index()]);
916 }
917
918 size_t reg_live = r->get_live_data_words();
919 if (reg_live != verf_live) {
920 ResourceMark rm;
921 stringStream ss;
922 r->print_on(&ss);
923 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
924 label, reg_live, verf_live, ss.as_string());
925 }
926 }
927 }
928
929 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
930
931
932 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
933 label, ShenandoahVerifyLevel, count_reachable, count_marked);
934
935 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
936 }
937
938 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
939 verify_at_safepoint(
940 "Generic Verification",
941 _verify_remembered_disable, // do not verify remembered set
942 _verify_forwarded_allow, // conservatively allow forwarded
943 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
944 _verify_cset_disable, // cset may be inconsistent
945 _verify_liveness_disable, // no reliable liveness data
946 _verify_regions_disable, // no reliable region data
947 _verify_gcstate_disable // no data about gcstate
948 );
949 }
950
951 void ShenandoahVerifier::verify_before_concmark() {
952 verify_at_safepoint(
953 "Before Mark",
954 _verify_remembered_for_marking, // verify read-only remembered set from bottom() to top()
955 _verify_forwarded_none, // UR should have fixed up
956 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
957 _verify_cset_none, // UR should have fixed this
958 _verify_liveness_disable, // no reliable liveness data
959 _verify_regions_notrash, // no trash regions
960 _verify_gcstate_stable // there are no forwarded objects
961 );
962 }
963
964 void ShenandoahVerifier::verify_after_concmark() {
965 verify_at_safepoint(
966 "After Mark",
967 _verify_remembered_disable, // do not verify remembered set
968 _verify_forwarded_none, // no forwarded references
969 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
970 _verify_cset_none, // no references to cset anymore
971 _verify_liveness_complete, // liveness data must be complete here
972 _verify_regions_disable, // trash regions not yet recycled
973 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
974 );
975 }
976
977 void ShenandoahVerifier::verify_before_evacuation() {
978 verify_at_safepoint(
979 "Before Evacuation",
980 _verify_remembered_disable, // do not verify remembered set
981 _verify_forwarded_none, // no forwarded references
982 _verify_marked_complete_except_references, // walk over marked objects too
983 _verify_cset_disable, // non-forwarded references to cset expected
984 _verify_liveness_complete, // liveness data must be complete here
985 _verify_regions_disable, // trash regions not yet recycled
986 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
987 );
988 }
989
990 void ShenandoahVerifier::verify_during_evacuation() {
991 verify_at_safepoint(
992 "During Evacuation",
993 _verify_remembered_disable, // do not verify remembered set
994 _verify_forwarded_allow, // some forwarded references are allowed
995 _verify_marked_disable, // walk only roots
996 _verify_cset_disable, // some cset references are not forwarded yet
997 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
998 _verify_regions_disable, // trash regions not yet recycled
999 _verify_gcstate_evacuation // evacuation is in progress
1000 );
1001 }
1002
1003 void ShenandoahVerifier::verify_after_evacuation() {
1004 verify_at_safepoint(
1005 "After Evacuation",
1006 _verify_remembered_disable, // do not verify remembered set
1007 _verify_forwarded_allow, // objects are still forwarded
1008 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1009 _verify_cset_forwarded, // all cset refs are fully forwarded
1010 _verify_liveness_disable, // no reliable liveness data anymore
1011 _verify_regions_notrash, // trash regions have been recycled already
1012 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1013 );
1014 }
1015
1016 void ShenandoahVerifier::verify_before_updaterefs() {
1017 verify_at_safepoint(
1018 "Before Updating References",
1019 _verify_remembered_for_updating_references, // verify read-write remembered set
1020 _verify_forwarded_allow, // forwarded references allowed
1021 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1022 _verify_cset_forwarded, // all cset refs are fully forwarded
1023 _verify_liveness_disable, // no reliable liveness data anymore
1024 _verify_regions_notrash, // trash regions have been recycled already
1025 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1026 );
1027 }
1028
1029 void ShenandoahVerifier::verify_after_updaterefs() {
1030 verify_at_safepoint(
1031 "After Updating References",
1032 _verify_remembered_disable, // do not verify remembered set
1033 _verify_forwarded_none, // no forwarded references
1034 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1035 _verify_cset_none, // no cset references, all updated
1036 _verify_liveness_disable, // no reliable liveness data anymore
1037 _verify_regions_nocset, // no cset regions, trash regions have appeared
1038 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1039 );
1040 }
1041
1042 void ShenandoahVerifier::verify_after_degenerated() {
1043 verify_at_safepoint(
1044 "After Degenerated GC",
1045 _verify_remembered_disable, // do not verify remembered set
1046 _verify_forwarded_none, // all objects are non-forwarded
1047 _verify_marked_complete, // all objects are marked in complete bitmap
1048 _verify_cset_none, // no cset references
1049 _verify_liveness_disable, // no reliable liveness data anymore
1050 _verify_regions_notrash_nocset, // no trash, no cset
1051 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1052 );
1053 }
1054
1055 void ShenandoahVerifier::verify_before_fullgc() {
1056 verify_at_safepoint(
1057 "Before Full GC",
1058 _verify_remembered_disable, // do not verify remembered set
1059 _verify_forwarded_allow, // can have forwarded objects
1060 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1061 _verify_cset_disable, // cset might be foobared
1062 _verify_liveness_disable, // no reliable liveness data anymore
1063 _verify_regions_disable, // no reliable region data here
1064 _verify_gcstate_disable // no reliable gcstate data
1065 );
1066 }
1067
1068 void ShenandoahVerifier::verify_after_generational_fullgc() {
1069 verify_at_safepoint(
1070 "After Full Generational GC",
1071 _verify_remembered_after_full_gc, // verify read-write remembered set
1072 _verify_forwarded_none, // all objects are non-forwarded
1073 _verify_marked_complete, // all objects are marked in complete bitmap
1074 _verify_cset_none, // no cset references
1075 _verify_liveness_disable, // no reliable liveness data anymore
1076 _verify_regions_notrash_nocset, // no trash, no cset
1077 _verify_gcstate_stable // full gc cleaned up everything
1078 );
1079 }
1080
1081 void ShenandoahVerifier::verify_after_fullgc() {
1082 verify_at_safepoint(
1083 "After Full GC",
1084 _verify_remembered_disable, // do not verify remembered set
1085 _verify_forwarded_none, // all objects are non-forwarded
1086 _verify_marked_complete, // all objects are marked in complete bitmap
1087 _verify_cset_none, // no cset references
1088 _verify_liveness_disable, // no reliable liveness data anymore
1089 _verify_regions_notrash_nocset, // no trash, no cset
1090 _verify_gcstate_stable // full gc cleaned up everything
1091 );
1092 }
1093
1094 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1095 private:
1096 template <class T>
1097 void do_oop_work(T* p) {
1098 T o = RawAccess<>::oop_load(p);
1099 if (!CompressedOops::is_null(o)) {
1100 oop obj = CompressedOops::decode_not_null(o);
1101 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1102 if (obj != fwd) {
1103 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1104 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1105 }
1106 }
1107 }
1108
1109 public:
1110 void do_oop(narrowOop* p) { do_oop_work(p); }
1111 void do_oop(oop* p) { do_oop_work(p); }
1112 };
1113
1114 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1115 private:
1116 template <class T>
1117 void do_oop_work(T* p) {
1118 T o = RawAccess<>::oop_load(p);
1119 if (!CompressedOops::is_null(o)) {
1120 oop obj = CompressedOops::decode_not_null(o);
1121 ShenandoahHeap* heap = ShenandoahHeap::heap();
1122
1123 if (!heap->marking_context()->is_marked_or_old(obj)) {
1124 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1125 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1126 }
1127
1128 if (heap->in_collection_set(obj)) {
1129 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1130 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1131 }
1132
1133 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1134 if (obj != fwd) {
1135 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1136 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1137 }
1138 }
1139 }
1140
1141 public:
1142 void do_oop(narrowOop* p) { do_oop_work(p); }
1143 void do_oop(oop* p) { do_oop_work(p); }
1144 };
1145
1146 void ShenandoahVerifier::verify_roots_in_to_space() {
1147 ShenandoahVerifyInToSpaceClosure cl;
1148 ShenandoahRootVerifier::roots_do(&cl);
1149 }
1150
1151 void ShenandoahVerifier::verify_roots_no_forwarded() {
1152 ShenandoahVerifyNoForwared cl;
1153 ShenandoahRootVerifier::roots_do(&cl);
1154 }