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