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 guarantee(stats.used() == generation->used(),
392 "%s: generation (%s) used size must be consistent: generation-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
393 label, generation->name(),
394 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
395 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
396 }
397 };
398
399 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
400 private:
401 ShenandoahHeap* _heap;
402 const char* _phase;
403 ShenandoahVerifier::VerifyRegions _regions;
404 public:
405 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
406 _heap(ShenandoahHeap::heap()),
407 _phase(phase),
408 _regions(regions) {};
409
410 void print_failure(ShenandoahHeapRegion* r, const char* label) {
411 ResourceMark rm;
412
413 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
414
415 stringStream ss;
416 r->print_on(&ss);
417 msg.append("%s", ss.as_string());
418
419 report_vm_error(__FILE__, __LINE__, msg.buffer());
420 }
421
422 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
423 if (!test) {
424 print_failure(r, msg);
425 }
426 }
427
428 void heap_region_do(ShenandoahHeapRegion* r) {
429 switch (_regions) {
430 case ShenandoahVerifier::_verify_regions_disable:
431 break;
432 case ShenandoahVerifier::_verify_regions_notrash:
433 verify(r, !r->is_trash(),
434 "Should not have trash regions");
435 break;
436 case ShenandoahVerifier::_verify_regions_nocset:
437 verify(r, !r->is_cset(),
438 "Should not have cset regions");
439 break;
440 case ShenandoahVerifier::_verify_regions_notrash_nocset:
441 verify(r, !r->is_trash(),
442 "Should not have trash regions");
443 verify(r, !r->is_cset(),
444 "Should not have cset regions");
445 break;
446 default:
447 ShouldNotReachHere();
448 }
449
450 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
451 "Capacity should match region size");
452
453 verify(r, r->bottom() <= r->top(),
454 "Region top should not be less than bottom");
455
456 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
457 "Region TAMS should not be less than bottom");
458
459 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
460 "Complete TAMS should not be larger than top");
461
462 verify(r, r->get_live_data_bytes() <= r->capacity(),
463 "Live data cannot be larger than capacity");
464
465 verify(r, r->garbage() <= r->capacity(),
466 "Garbage cannot be larger than capacity");
467
468 verify(r, r->used() <= r->capacity(),
469 "Used cannot be larger than capacity");
470
471 verify(r, r->get_shared_allocs() <= r->capacity(),
472 "Shared alloc count should not be larger than capacity");
473
474 verify(r, r->get_tlab_allocs() <= r->capacity(),
475 "TLAB alloc count should not be larger than capacity");
476
477 verify(r, r->get_gclab_allocs() <= r->capacity(),
478 "GCLAB alloc count should not be larger than capacity");
479
480 verify(r, r->get_plab_allocs() <= r->capacity(),
481 "PLAB alloc count should not be larger than capacity");
482
483 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
484 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
485
486 verify(r, !r->is_empty() || !r->has_live(),
487 "Empty regions should not have live data");
488
489 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
490 "Transitional: region flags and collection set agree");
491 }
492 };
493
494 class ShenandoahVerifierReachableTask : public AbstractGangTask {
495 private:
496 const char* _label;
497 ShenandoahVerifier::VerifyOptions _options;
498 ShenandoahHeap* _heap;
499 ShenandoahLivenessData* _ld;
500 MarkBitMap* _bitmap;
501 volatile size_t _processed;
502
503 public:
504 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
505 ShenandoahLivenessData* ld,
506 const char* label,
507 ShenandoahVerifier::VerifyOptions options) :
508 AbstractGangTask("Shenandoah Verifier Reachable Objects"),
509 _label(label),
510 _options(options),
511 _heap(ShenandoahHeap::heap()),
512 _ld(ld),
513 _bitmap(bitmap),
514 _processed(0) {};
515
516 size_t processed() {
517 return _processed;
518 }
519
520 virtual void work(uint worker_id) {
521 ResourceMark rm;
522 ShenandoahVerifierStack stack;
523
524 // On level 2, we need to only check the roots once.
525 // On level 3, we want to check the roots, and seed the local stack.
526 // It is a lesser evil to accept multiple root scans at level 3, because
527 // extended parallelism would buy us out.
528 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
529 || (ShenandoahVerifyLevel >= 3)) {
530 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
531 ShenandoahMessageBuffer("%s, Roots", _label),
532 _options);
533 if (_heap->unload_classes()) {
534 ShenandoahRootVerifier::strong_roots_do(&cl);
535 } else {
536 ShenandoahRootVerifier::roots_do(&cl);
537 }
538 }
539
540 size_t processed = 0;
541
542 if (ShenandoahVerifyLevel >= 3) {
543 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
544 ShenandoahMessageBuffer("%s, Reachable", _label),
545 _options);
546 while (!stack.is_empty()) {
547 processed++;
548 ShenandoahVerifierTask task = stack.pop();
549 cl.verify_oops_from(task.obj());
550 }
551 }
552
553 Atomic::add(&_processed, processed, memory_order_relaxed);
554 }
555 };
556
557 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
558 private:
559 const char* _label;
560 ShenandoahVerifier::VerifyOptions _options;
561 ShenandoahHeap* _heap;
562 MarkBitMap* _bitmap;
563 ShenandoahLivenessData* _ld;
564 volatile size_t _claimed;
565 volatile size_t _processed;
566 ShenandoahGeneration* _generation;
567
568 public:
569 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
570 ShenandoahLivenessData* ld,
571 const char* label,
572 ShenandoahVerifier::VerifyOptions options) :
573 AbstractGangTask("Shenandoah Verifier Marked Objects"),
574 _label(label),
575 _options(options),
576 _heap(ShenandoahHeap::heap()),
577 _bitmap(bitmap),
578 _ld(ld),
579 _claimed(0),
580 _processed(0),
581 _generation(NULL) {
582 if (_heap->mode()->is_generational()) {
583 _generation = _heap->active_generation();
584 assert(_generation != NULL, "Expected active generation in this mode.");
585 }
586 };
587
588 size_t processed() {
589 return Atomic::load(&_processed);
590 }
591
592 virtual void work(uint worker_id) {
593 ShenandoahVerifierStack stack;
594 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
595 ShenandoahMessageBuffer("%s, Marked", _label),
596 _options);
597
598 while (true) {
599 size_t v = Atomic::fetch_and_add(&_claimed, 1u, memory_order_relaxed);
600 if (v < _heap->num_regions()) {
601 ShenandoahHeapRegion* r = _heap->get_region(v);
602 if (!in_generation(r)) {
603 continue;
604 }
605
606 if (!r->is_humongous() && !r->is_trash()) {
607 work_regular(r, stack, cl);
608 } else if (r->is_humongous_start()) {
609 work_humongous(r, stack, cl);
610 }
611 } else {
612 break;
613 }
614 }
615 }
616
617 bool in_generation(ShenandoahHeapRegion* r) {
618 return _generation == NULL || _generation->contains(r);
619 }
620
621 virtual void work_humongous(ShenandoahHeapRegion* r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
622 size_t processed = 0;
623 HeapWord* obj = r->bottom();
624 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
625 verify_and_follow(obj, stack, cl, &processed);
626 }
627 Atomic::add(&_processed, processed, memory_order_relaxed);
628 }
629
630 virtual void work_regular(ShenandoahHeapRegion* r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
631 size_t processed = 0;
632 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
633 HeapWord* tams = ctx->top_at_mark_start(r);
634
635 // Bitmaps, before TAMS
636 if (tams > r->bottom()) {
637 HeapWord* start = r->bottom();
638 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
639
640 while (addr < tams) {
641 verify_and_follow(addr, stack, cl, &processed);
642 addr += 1;
643 if (addr < tams) {
644 addr = ctx->get_next_marked_addr(addr, tams);
645 }
646 }
647 }
648
649 // Size-based, after TAMS
650 {
651 HeapWord* limit = r->top();
652 HeapWord* addr = tams;
653
654 while (addr < limit) {
655 verify_and_follow(addr, stack, cl, &processed);
656 addr += cast_to_oop(addr)->size();
657 }
658 }
659
660 Atomic::add(&_processed, processed, memory_order_relaxed);
661 }
662
663 void verify_and_follow(HeapWord* addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t* processed) {
664 if (!_bitmap->par_mark(addr)) return;
665
666 // Verify the object itself:
667 oop obj = cast_to_oop(addr);
668 cl.verify_oop_standalone(obj);
669
670 // Verify everything reachable from that object too, hopefully realizing
671 // everything was already marked, and never touching further:
672 if (!is_instance_ref_klass(obj->klass())) {
673 cl.verify_oops_from(obj);
674 (*processed)++;
675 }
676 while (!stack.is_empty()) {
677 ShenandoahVerifierTask task = stack.pop();
678 cl.verify_oops_from(task.obj());
679 (*processed)++;
680 }
681 }
682 };
683
684 class VerifyThreadGCState : public ThreadClosure {
685 private:
686 const char* const _label;
687 char const _expected;
688
689 public:
690 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
691 void do_thread(Thread* t) {
692 char actual = ShenandoahThreadLocalData::gc_state(t);
693 if (actual != _expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
694 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
695 }
696 }
697 };
698
699 void ShenandoahVerifier::verify_at_safepoint(const char* label,
700 VerifyRememberedSet remembered,
701 VerifyForwarded forwarded, VerifyMarked marked,
702 VerifyCollectionSet cset,
703 VerifyLiveness liveness, VerifyRegions regions,
704 VerifyGCState gcstate) {
705 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
706 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
707
708 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
709 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
710
711 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
712
713 // GC state checks
714 {
715 char expected = -1;
716 bool enabled;
717 switch (gcstate) {
718 case _verify_gcstate_disable:
719 enabled = false;
720 break;
721 case _verify_gcstate_forwarded:
722 enabled = true;
723 expected = ShenandoahHeap::HAS_FORWARDED;
724 break;
725 case _verify_gcstate_evacuation:
726 enabled = true;
727 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
728 if (!_heap->is_stw_gc_in_progress()) {
729 // Only concurrent GC sets this.
730 expected |= ShenandoahHeap::WEAK_ROOTS;
731 }
732 break;
733 case _verify_gcstate_updating:
734 enabled = true;
735 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
736 break;
737 case _verify_gcstate_stable:
738 enabled = true;
739 expected = ShenandoahHeap::STABLE;
740 break;
741 case _verify_gcstate_stable_weakroots:
742 enabled = true;
743 expected = ShenandoahHeap::STABLE;
744 if (!_heap->is_stw_gc_in_progress()) {
745 // Only concurrent GC sets this.
746 expected |= ShenandoahHeap::WEAK_ROOTS;
747 }
748 break;
749 default:
750 enabled = false;
751 assert(false, "Unhandled gc-state verification");
752 }
753
754 if (enabled) {
755 char actual = _heap->gc_state();
756 // Old generation marking is allowed in all states.
757 if (actual != expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
758 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
759 }
760
761 VerifyThreadGCState vtgcs(label, expected);
762 Threads::java_threads_do(&vtgcs);
763 }
764 }
765
766 // Deactivate barriers temporarily: Verifier wants plain heap accesses
767 ShenandoahGCStateResetter resetter;
768
769 // Heap size checks
770 {
771 ShenandoahHeapLocker lock(_heap->lock());
772
773 ShenandoahCalculateRegionStatsClosure cl;
774 _heap->heap_region_iterate(&cl);
775
776 size_t heap_used = _heap->used();
777 guarantee(cl.used() == heap_used,
778 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
779 label,
780 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
781 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
782
783 size_t heap_committed = _heap->committed();
784 guarantee(cl.committed() == heap_committed,
785 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
786 label,
787 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
788 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
789 }
790
791 log_debug(gc)("Safepoint verification finished heap usage verification");
792
793 ShenandoahGeneration* generation;
794 if (_heap->mode()->is_generational()) {
795 generation = _heap->active_generation();
796 guarantee(generation != NULL, "Need to know which generation to verify.");
797 } else {
798 generation = NULL;
799 }
800
801 if (generation != NULL) {
802 ShenandoahHeapLocker lock(_heap->lock());
803
804 if (remembered == _verify_remembered_for_marking) {
805 log_debug(gc)("Safepoint verification of remembered set at mark");
806 } else if (remembered == _verify_remembered_for_updating_references) {
807 log_debug(gc)("Safepoint verification of remembered set at update ref");
808 } else if (remembered == _verify_remembered_after_full_gc) {
809 log_debug(gc)("Safepoint verification of remembered set after full gc");
810 }
811
812 if (remembered == _verify_remembered_for_marking) {
813 _heap->verify_rem_set_at_mark();
814 } else if (remembered == _verify_remembered_for_updating_references) {
815 _heap->verify_rem_set_at_update_ref();
816 } else if (remembered == _verify_remembered_after_full_gc) {
817 _heap->verify_rem_set_after_full_gc();
818 }
819
820 ShenandoahGenerationStatsClosure cl;
821 _heap->heap_region_iterate(&cl);
822
823 if (LogTarget(Debug, gc)::is_enabled()) {
824 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
825 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
826 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
827 }
828
829 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->old_generation(), cl.old);
830 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->young_generation(), cl.young);
831 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->global_generation(), cl.global);
832 }
833
834 log_debug(gc)("Safepoint verification finished remembered set verification");
835
836 // Internal heap region checks
837 if (ShenandoahVerifyLevel >= 1) {
838 ShenandoahVerifyHeapRegionClosure cl(label, regions);
839 if (generation != NULL) {
840 generation->heap_region_iterate(&cl);
841 } else {
842 _heap->heap_region_iterate(&cl);
843 }
844 }
845
846 log_debug(gc)("Safepoint verification finished heap region closure verification");
847
848 OrderAccess::fence();
849
850 if (UseTLAB) {
851 _heap->labs_make_parsable();
852 }
853
854 // Allocate temporary bitmap for storing marking wavefront:
855 _verification_bit_map->clear();
856
857 // Allocate temporary array for storing liveness data
858 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
859 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
860
861 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
862
863 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
864 // This verifies what application can see, since it only cares about reachable objects.
865 size_t count_reachable = 0;
866 if (ShenandoahVerifyLevel >= 2) {
867 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
868 _heap->workers()->run_task(&task);
869 count_reachable = task.processed();
870 }
871
872 log_debug(gc)("Safepoint verification finished getting initial reachable set");
873
874 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
875 // not the application, can see during the region scans. There is no reason to process the objects
876 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
877 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
878 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
879 // version
880
881 size_t count_marked = 0;
882 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
883 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
884 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
885 _heap->workers()->run_task(&task);
886 count_marked = task.processed();
887 } else {
888 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
889 }
890
891 log_debug(gc)("Safepoint verification finished walking marked objects");
892
893 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
894 // marked objects.
895
896 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
897 for (size_t i = 0; i < _heap->num_regions(); i++) {
898 ShenandoahHeapRegion* r = _heap->get_region(i);
899 if (generation != NULL && !generation->contains(r)) {
900 continue;
901 }
902
903 juint verf_live = 0;
904 if (r->is_humongous()) {
905 // For humongous objects, test if start region is marked live, and if so,
906 // all humongous regions in that chain have live data equal to their "used".
907 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
908 if (start_live > 0) {
909 verf_live = (juint)(r->used() / HeapWordSize);
910 }
911 } else {
912 verf_live = Atomic::load(&ld[r->index()]);
913 }
914
915 size_t reg_live = r->get_live_data_words();
916 if (reg_live != verf_live) {
917 ResourceMark rm;
918 stringStream ss;
919 r->print_on(&ss);
920 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
921 label, reg_live, verf_live, ss.as_string());
922 }
923 }
924 }
925
926 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
927
928
929 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
930 label, ShenandoahVerifyLevel, count_reachable, count_marked);
931
932 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
933 }
934
935 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
936 verify_at_safepoint(
937 "Generic Verification",
938 _verify_remembered_disable, // do not verify remembered set
939 _verify_forwarded_allow, // conservatively allow forwarded
940 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
941 _verify_cset_disable, // cset may be inconsistent
942 _verify_liveness_disable, // no reliable liveness data
943 _verify_regions_disable, // no reliable region data
944 _verify_gcstate_disable // no data about gcstate
945 );
946 }
947
948 void ShenandoahVerifier::verify_before_concmark() {
949 verify_at_safepoint(
950 "Before Mark",
951 _verify_remembered_for_marking, // verify read-only remembered set from bottom() to top()
952 _verify_forwarded_none, // UR should have fixed up
953 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
954 _verify_cset_none, // UR should have fixed this
955 _verify_liveness_disable, // no reliable liveness data
956 _verify_regions_notrash, // no trash regions
957 _verify_gcstate_stable // there are no forwarded objects
958 );
959 }
960
961 void ShenandoahVerifier::verify_after_concmark() {
962 verify_at_safepoint(
963 "After Mark",
964 _verify_remembered_disable, // do not verify remembered set
965 _verify_forwarded_none, // no forwarded references
966 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
967 _verify_cset_none, // no references to cset anymore
968 _verify_liveness_complete, // liveness data must be complete here
969 _verify_regions_disable, // trash regions not yet recycled
970 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
971 );
972 }
973
974 void ShenandoahVerifier::verify_before_evacuation() {
975 verify_at_safepoint(
976 "Before Evacuation",
977 _verify_remembered_disable, // do not verify remembered set
978 _verify_forwarded_none, // no forwarded references
979 _verify_marked_complete_except_references, // walk over marked objects too
980 _verify_cset_disable, // non-forwarded references to cset expected
981 _verify_liveness_complete, // liveness data must be complete here
982 _verify_regions_disable, // trash regions not yet recycled
983 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
984 );
985 }
986
987 void ShenandoahVerifier::verify_during_evacuation() {
988 verify_at_safepoint(
989 "During Evacuation",
990 _verify_remembered_disable, // do not verify remembered set
991 _verify_forwarded_allow, // some forwarded references are allowed
992 _verify_marked_disable, // walk only roots
993 _verify_cset_disable, // some cset references are not forwarded yet
994 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
995 _verify_regions_disable, // trash regions not yet recycled
996 _verify_gcstate_evacuation // evacuation is in progress
997 );
998 }
999
1000 void ShenandoahVerifier::verify_after_evacuation() {
1001 verify_at_safepoint(
1002 "After Evacuation",
1003 _verify_remembered_disable, // do not verify remembered set
1004 _verify_forwarded_allow, // objects are still forwarded
1005 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1006 _verify_cset_forwarded, // all cset refs are fully forwarded
1007 _verify_liveness_disable, // no reliable liveness data anymore
1008 _verify_regions_notrash, // trash regions have been recycled already
1009 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1010 );
1011 }
1012
1013 void ShenandoahVerifier::verify_before_updaterefs() {
1014 verify_at_safepoint(
1015 "Before Updating References",
1016 _verify_remembered_for_updating_references, // verify read-write remembered set
1017 _verify_forwarded_allow, // forwarded references allowed
1018 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1019 _verify_cset_forwarded, // all cset refs are fully forwarded
1020 _verify_liveness_disable, // no reliable liveness data anymore
1021 _verify_regions_notrash, // trash regions have been recycled already
1022 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1023 );
1024 }
1025
1026 void ShenandoahVerifier::verify_after_updaterefs() {
1027 verify_at_safepoint(
1028 "After Updating References",
1029 _verify_remembered_disable, // do not verify remembered set
1030 _verify_forwarded_none, // no forwarded references
1031 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1032 _verify_cset_none, // no cset references, all updated
1033 _verify_liveness_disable, // no reliable liveness data anymore
1034 _verify_regions_nocset, // no cset regions, trash regions have appeared
1035 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1036 );
1037 }
1038
1039 void ShenandoahVerifier::verify_after_degenerated() {
1040 verify_at_safepoint(
1041 "After Degenerated GC",
1042 _verify_remembered_disable, // do not verify remembered set
1043 _verify_forwarded_none, // all objects are non-forwarded
1044 _verify_marked_complete, // all objects are marked in complete bitmap
1045 _verify_cset_none, // no cset references
1046 _verify_liveness_disable, // no reliable liveness data anymore
1047 _verify_regions_notrash_nocset, // no trash, no cset
1048 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1049 );
1050 }
1051
1052 void ShenandoahVerifier::verify_before_fullgc() {
1053 verify_at_safepoint(
1054 "Before Full GC",
1055 _verify_remembered_disable, // do not verify remembered set
1056 _verify_forwarded_allow, // can have forwarded objects
1057 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1058 _verify_cset_disable, // cset might be foobared
1059 _verify_liveness_disable, // no reliable liveness data anymore
1060 _verify_regions_disable, // no reliable region data here
1061 _verify_gcstate_disable // no reliable gcstate data
1062 );
1063 }
1064
1065 void ShenandoahVerifier::verify_after_generational_fullgc() {
1066 verify_at_safepoint(
1067 "After Full Generational GC",
1068 _verify_remembered_after_full_gc, // verify read-write remembered set
1069 _verify_forwarded_none, // all objects are non-forwarded
1070 _verify_marked_complete, // all objects are marked in complete bitmap
1071 _verify_cset_none, // no cset references
1072 _verify_liveness_disable, // no reliable liveness data anymore
1073 _verify_regions_notrash_nocset, // no trash, no cset
1074 _verify_gcstate_stable // full gc cleaned up everything
1075 );
1076 }
1077
1078 void ShenandoahVerifier::verify_after_fullgc() {
1079 verify_at_safepoint(
1080 "After Full GC",
1081 _verify_remembered_disable, // do not verify remembered set
1082 _verify_forwarded_none, // all objects are non-forwarded
1083 _verify_marked_complete, // all objects are marked in complete bitmap
1084 _verify_cset_none, // no cset references
1085 _verify_liveness_disable, // no reliable liveness data anymore
1086 _verify_regions_notrash_nocset, // no trash, no cset
1087 _verify_gcstate_stable // full gc cleaned up everything
1088 );
1089 }
1090
1091 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1092 private:
1093 template <class T>
1094 void do_oop_work(T* p) {
1095 T o = RawAccess<>::oop_load(p);
1096 if (!CompressedOops::is_null(o)) {
1097 oop obj = CompressedOops::decode_not_null(o);
1098 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1099 if (obj != fwd) {
1100 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1101 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1102 }
1103 }
1104 }
1105
1106 public:
1107 void do_oop(narrowOop* p) { do_oop_work(p); }
1108 void do_oop(oop* p) { do_oop_work(p); }
1109 };
1110
1111 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1112 private:
1113 template <class T>
1114 void do_oop_work(T* p) {
1115 T o = RawAccess<>::oop_load(p);
1116 if (!CompressedOops::is_null(o)) {
1117 oop obj = CompressedOops::decode_not_null(o);
1118 ShenandoahHeap* heap = ShenandoahHeap::heap();
1119
1120 if (!heap->marking_context()->is_marked_or_old(obj)) {
1121 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1122 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1123 }
1124
1125 if (heap->in_collection_set(obj)) {
1126 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1127 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1128 }
1129
1130 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1131 if (obj != fwd) {
1132 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1133 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1134 }
1135 }
1136 }
1137
1138 public:
1139 void do_oop(narrowOop* p) { do_oop_work(p); }
1140 void do_oop(oop* p) { do_oop_work(p); }
1141 };
1142
1143 void ShenandoahVerifier::verify_roots_in_to_space() {
1144 ShenandoahVerifyInToSpaceClosure cl;
1145 ShenandoahRootVerifier::roots_do(&cl);
1146 }
1147
1148 void ShenandoahVerifier::verify_roots_no_forwarded() {
1149 ShenandoahVerifyNoForwared cl;
1150 ShenandoahRootVerifier::roots_do(&cl);
1151 }