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 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
344 // a subset (e.g. the young generation or old generation) of the total heap.
345 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
346 private:
347 size_t _used, _committed, _garbage, _regions;
348 public:
349 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0), _regions(0) {};
350
351 void heap_region_do(ShenandoahHeapRegion* r) {
352 _used += r->used();
353 log_debug(gc)("ShenandoahCalculateRegionStatsClosure added " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
354 r->used(), r->is_humongous()? "humongous": "regular", r->index(), _used);
355 _garbage += r->garbage();
356 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
357 _regions++;
358 }
359
360 size_t used() { return _used; }
361 size_t committed() { return _committed; }
362 size_t garbage() { return _garbage; }
363 size_t regions() { return _regions; }
364
365 // span is the total memory affiliated with these stats (some of which is in use and other is available)
366 size_t span() { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
367 };
368
369 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
370 public:
371 ShenandoahCalculateRegionStatsClosure old;
372 ShenandoahCalculateRegionStatsClosure young;
373 ShenandoahCalculateRegionStatsClosure global;
374
375 void heap_region_do(ShenandoahHeapRegion* r) override {
376 switch (r->affiliation()) {
377 default:
378 ShouldNotReachHere();
379 return;
380 case FREE: return;
381 case YOUNG_GENERATION:
382 young.heap_region_do(r);
383 break;
384 case OLD_GENERATION:
385 old.heap_region_do(r);
386 break;
387 }
388 global.heap_region_do(r);
389 }
390
391 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
392 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
393 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 static void validate_usage(const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
399 size_t generation_used = generation->used();
400 guarantee(stats.used() == generation_used,
401 "%s: generation (%s) used size must be consistent: generation-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
402 label, generation->name(),
403 byte_size_in_proper_unit(generation_used), proper_unit_for_byte_size(generation_used),
404 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
405
406 guarantee(stats.regions() == generation->used_regions(),
407 "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
408 label, generation->name(), generation->used_regions(), stats.regions());
409
410 size_t capacity = generation->adjusted_capacity();
411 guarantee(stats.span() <= capacity,
412 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") must not exceed current capacity (" SIZE_FORMAT "%s)",
413 label, generation->name(), stats.regions(),
414 byte_size_in_proper_unit(capacity), proper_unit_for_byte_size(capacity));
415
416 }
417 };
418
419 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
420 private:
421 ShenandoahHeap* _heap;
422 const char* _phase;
423 ShenandoahVerifier::VerifyRegions _regions;
424 public:
425 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
426 _heap(ShenandoahHeap::heap()),
427 _phase(phase),
428 _regions(regions) {};
429
430 void print_failure(ShenandoahHeapRegion* r, const char* label) {
431 ResourceMark rm;
432
433 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
434
435 stringStream ss;
436 r->print_on(&ss);
437 msg.append("%s", ss.as_string());
438
439 report_vm_error(__FILE__, __LINE__, msg.buffer());
440 }
441
442 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
443 if (!test) {
444 print_failure(r, msg);
445 }
446 }
447
448 void heap_region_do(ShenandoahHeapRegion* r) {
449 switch (_regions) {
450 case ShenandoahVerifier::_verify_regions_disable:
451 break;
452 case ShenandoahVerifier::_verify_regions_notrash:
453 verify(r, !r->is_trash(),
454 "Should not have trash regions");
455 break;
456 case ShenandoahVerifier::_verify_regions_nocset:
457 verify(r, !r->is_cset(),
458 "Should not have cset regions");
459 break;
460 case ShenandoahVerifier::_verify_regions_notrash_nocset:
461 verify(r, !r->is_trash(),
462 "Should not have trash regions");
463 verify(r, !r->is_cset(),
464 "Should not have cset regions");
465 break;
466 default:
467 ShouldNotReachHere();
468 }
469
470 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
471 "Capacity should match region size");
472
473 verify(r, r->bottom() <= r->top(),
474 "Region top should not be less than bottom");
475
476 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
477 "Region TAMS should not be less than bottom");
478
479 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
480 "Complete TAMS should not be larger than top");
481
482 verify(r, r->get_live_data_bytes() <= r->capacity(),
483 "Live data cannot be larger than capacity");
484
485 verify(r, r->garbage() <= r->capacity(),
486 "Garbage cannot be larger than capacity");
487
488 verify(r, r->used() <= r->capacity(),
489 "Used cannot be larger than capacity");
490
491 verify(r, r->get_shared_allocs() <= r->capacity(),
492 "Shared alloc count should not be larger than capacity");
493
494 verify(r, r->get_tlab_allocs() <= r->capacity(),
495 "TLAB alloc count should not be larger than capacity");
496
497 verify(r, r->get_gclab_allocs() <= r->capacity(),
498 "GCLAB alloc count should not be larger than capacity");
499
500 verify(r, r->get_plab_allocs() <= r->capacity(),
501 "PLAB alloc count should not be larger than capacity");
502
503 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
504 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
505
506 verify(r, !r->is_empty() || !r->has_live(),
507 "Empty regions should not have live data");
508
509 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
510 "Transitional: region flags and collection set agree");
511 }
512 };
513
514 class ShenandoahVerifierReachableTask : public WorkerTask {
515 private:
516 const char* _label;
517 ShenandoahVerifier::VerifyOptions _options;
518 ShenandoahHeap* _heap;
519 ShenandoahLivenessData* _ld;
520 MarkBitMap* _bitmap;
521 volatile size_t _processed;
522
523 public:
524 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
525 ShenandoahLivenessData* ld,
526 const char* label,
527 ShenandoahVerifier::VerifyOptions options) :
528 WorkerTask("Shenandoah Verifier Reachable Objects"),
529 _label(label),
530 _options(options),
531 _heap(ShenandoahHeap::heap()),
532 _ld(ld),
533 _bitmap(bitmap),
534 _processed(0) {};
535
536 size_t processed() {
537 return _processed;
538 }
539
540 virtual void work(uint worker_id) {
541 ResourceMark rm;
542 ShenandoahVerifierStack stack;
543
544 // On level 2, we need to only check the roots once.
545 // On level 3, we want to check the roots, and seed the local stack.
546 // It is a lesser evil to accept multiple root scans at level 3, because
547 // extended parallelism would buy us out.
548 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
549 || (ShenandoahVerifyLevel >= 3)) {
550 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
551 ShenandoahMessageBuffer("%s, Roots", _label),
552 _options);
553 if (_heap->unload_classes()) {
554 ShenandoahRootVerifier::strong_roots_do(&cl);
555 } else {
556 ShenandoahRootVerifier::roots_do(&cl);
557 }
558 }
559
560 size_t processed = 0;
561
562 if (ShenandoahVerifyLevel >= 3) {
563 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
564 ShenandoahMessageBuffer("%s, Reachable", _label),
565 _options);
566 while (!stack.is_empty()) {
567 processed++;
568 ShenandoahVerifierTask task = stack.pop();
569 cl.verify_oops_from(task.obj());
570 }
571 }
572
573 Atomic::add(&_processed, processed, memory_order_relaxed);
574 }
575 };
576
577 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
578 private:
579 const char* _label;
580 ShenandoahVerifier::VerifyOptions _options;
581 ShenandoahHeap* _heap;
582 MarkBitMap* _bitmap;
583 ShenandoahLivenessData* _ld;
584 volatile size_t _claimed;
585 volatile size_t _processed;
586 ShenandoahGeneration* _generation;
587
588 public:
589 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
590 ShenandoahLivenessData* ld,
591 const char* label,
592 ShenandoahVerifier::VerifyOptions options) :
593 WorkerTask("Shenandoah Verifier Marked Objects"),
594 _label(label),
595 _options(options),
596 _heap(ShenandoahHeap::heap()),
597 _bitmap(bitmap),
598 _ld(ld),
599 _claimed(0),
600 _processed(0),
601 _generation(NULL) {
602 if (_heap->mode()->is_generational()) {
603 _generation = _heap->active_generation();
604 assert(_generation != NULL, "Expected active generation in this mode.");
605 }
606 };
607
608 size_t processed() {
609 return Atomic::load(&_processed);
610 }
611
612 virtual void work(uint worker_id) {
613 ShenandoahVerifierStack stack;
614 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
615 ShenandoahMessageBuffer("%s, Marked", _label),
616 _options);
617
618 while (true) {
619 size_t v = Atomic::fetch_and_add(&_claimed, 1u, memory_order_relaxed);
620 if (v < _heap->num_regions()) {
621 ShenandoahHeapRegion* r = _heap->get_region(v);
622 if (!in_generation(r)) {
623 continue;
624 }
625
626 if (!r->is_humongous() && !r->is_trash()) {
627 work_regular(r, stack, cl);
628 } else if (r->is_humongous_start()) {
629 work_humongous(r, stack, cl);
630 }
631 } else {
632 break;
633 }
634 }
635 }
636
637 bool in_generation(ShenandoahHeapRegion* r) {
638 return _generation == NULL || _generation->contains(r);
639 }
640
641 virtual void work_humongous(ShenandoahHeapRegion* r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
642 size_t processed = 0;
643 HeapWord* obj = r->bottom();
644 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
645 verify_and_follow(obj, stack, cl, &processed);
646 }
647 Atomic::add(&_processed, processed, memory_order_relaxed);
648 }
649
650 virtual void work_regular(ShenandoahHeapRegion* r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
651 size_t processed = 0;
652 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
653 HeapWord* tams = ctx->top_at_mark_start(r);
654
655 // Bitmaps, before TAMS
656 if (tams > r->bottom()) {
657 HeapWord* start = r->bottom();
658 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
659
660 while (addr < tams) {
661 verify_and_follow(addr, stack, cl, &processed);
662 addr += 1;
663 if (addr < tams) {
664 addr = ctx->get_next_marked_addr(addr, tams);
665 }
666 }
667 }
668
669 // Size-based, after TAMS
670 {
671 HeapWord* limit = r->top();
672 HeapWord* addr = tams;
673
674 while (addr < limit) {
675 verify_and_follow(addr, stack, cl, &processed);
676 addr += cast_to_oop(addr)->size();
677 }
678 }
679
680 Atomic::add(&_processed, processed, memory_order_relaxed);
681 }
682
683 void verify_and_follow(HeapWord* addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t* processed) {
684 if (!_bitmap->par_mark(addr)) return;
685
686 // Verify the object itself:
687 oop obj = cast_to_oop(addr);
688 cl.verify_oop_standalone(obj);
689
690 // Verify everything reachable from that object too, hopefully realizing
691 // everything was already marked, and never touching further:
692 if (!is_instance_ref_klass(obj->klass())) {
693 cl.verify_oops_from(obj);
694 (*processed)++;
695 }
696 while (!stack.is_empty()) {
697 ShenandoahVerifierTask task = stack.pop();
698 cl.verify_oops_from(task.obj());
699 (*processed)++;
700 }
701 }
702 };
703
704 class VerifyThreadGCState : public ThreadClosure {
705 private:
706 const char* const _label;
707 char const _expected;
708
709 public:
710 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
711 void do_thread(Thread* t) {
712 char actual = ShenandoahThreadLocalData::gc_state(t);
713 if (actual != _expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
714 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
715 }
716 }
717 };
718
719 void ShenandoahVerifier::verify_at_safepoint(const char* label,
720 VerifyRememberedSet remembered,
721 VerifyForwarded forwarded, VerifyMarked marked,
722 VerifyCollectionSet cset,
723 VerifyLiveness liveness, VerifyRegions regions,
724 VerifyGCState gcstate) {
725 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
726 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
727
728 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
729 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
730
731 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
732
733 // GC state checks
734 {
735 char expected = -1;
736 bool enabled;
737 switch (gcstate) {
738 case _verify_gcstate_disable:
739 enabled = false;
740 break;
741 case _verify_gcstate_forwarded:
742 enabled = true;
743 expected = ShenandoahHeap::HAS_FORWARDED;
744 break;
745 case _verify_gcstate_evacuation:
746 enabled = true;
747 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
748 if (!_heap->is_stw_gc_in_progress()) {
749 // Only concurrent GC sets this.
750 expected |= ShenandoahHeap::WEAK_ROOTS;
751 }
752 break;
753 case _verify_gcstate_updating:
754 enabled = true;
755 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
756 break;
757 case _verify_gcstate_stable:
758 enabled = true;
759 expected = ShenandoahHeap::STABLE;
760 break;
761 case _verify_gcstate_stable_weakroots:
762 enabled = true;
763 expected = ShenandoahHeap::STABLE;
764 if (!_heap->is_stw_gc_in_progress()) {
765 // Only concurrent GC sets this.
766 expected |= ShenandoahHeap::WEAK_ROOTS;
767 }
768 break;
769 default:
770 enabled = false;
771 assert(false, "Unhandled gc-state verification");
772 }
773
774 if (enabled) {
775 char actual = _heap->gc_state();
776 // Old generation marking is allowed in all states.
777 if (actual != expected && !(actual & ShenandoahHeap::OLD_MARKING)) {
778 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
779 }
780
781 VerifyThreadGCState vtgcs(label, expected);
782 Threads::java_threads_do(&vtgcs);
783 }
784 }
785
786 // Deactivate barriers temporarily: Verifier wants plain heap accesses
787 ShenandoahGCStateResetter resetter;
788
789 // Heap size checks
790 {
791 ShenandoahHeapLocker lock(_heap->lock());
792
793 ShenandoahCalculateRegionStatsClosure cl;
794 _heap->heap_region_iterate(&cl);
795 size_t heap_used = _heap->used();
796 guarantee(cl.used() == heap_used,
797 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
798 label,
799 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
800 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
801
802 size_t heap_committed = _heap->committed();
803 guarantee(cl.committed() == heap_committed,
804 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
805 label,
806 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
807 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
808 }
809
810 log_debug(gc)("Safepoint verification finished heap usage verification");
811
812 ShenandoahGeneration* generation;
813 if (_heap->mode()->is_generational()) {
814 generation = _heap->active_generation();
815 guarantee(generation != NULL, "Need to know which generation to verify.");
816 } else {
817 generation = NULL;
818 }
819
820 if (generation != NULL) {
821 ShenandoahHeapLocker lock(_heap->lock());
822
823 if (remembered == _verify_remembered_for_marking) {
824 log_debug(gc)("Safepoint verification of remembered set at mark");
825 } else if (remembered == _verify_remembered_for_updating_references) {
826 log_debug(gc)("Safepoint verification of remembered set at update ref");
827 } else if (remembered == _verify_remembered_after_full_gc) {
828 log_debug(gc)("Safepoint verification of remembered set after full gc");
829 }
830
831 if (remembered == _verify_remembered_for_marking) {
832 _heap->verify_rem_set_at_mark();
833 } else if (remembered == _verify_remembered_for_updating_references) {
834 _heap->verify_rem_set_at_update_ref();
835 } else if (remembered == _verify_remembered_after_full_gc) {
836 _heap->verify_rem_set_after_full_gc();
837 }
838
839 ShenandoahGenerationStatsClosure cl;
840 _heap->heap_region_iterate(&cl);
841
842 if (LogTarget(Debug, gc)::is_enabled()) {
843 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
844 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
845 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
846 }
847
848 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->old_generation(), cl.old);
849 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->young_generation(), cl.young);
850 ShenandoahGenerationStatsClosure::validate_usage(label, _heap->global_generation(), cl.global);
851 }
852
853 log_debug(gc)("Safepoint verification finished remembered set verification");
854
855 // Internal heap region checks
856 if (ShenandoahVerifyLevel >= 1) {
857 ShenandoahVerifyHeapRegionClosure cl(label, regions);
858 if (generation != NULL) {
859 generation->heap_region_iterate(&cl);
860 } else {
861 _heap->heap_region_iterate(&cl);
862 }
863 }
864
865 log_debug(gc)("Safepoint verification finished heap region closure verification");
866
867 OrderAccess::fence();
868
869 if (UseTLAB) {
870 _heap->labs_make_parsable();
871 }
872
873 // Allocate temporary bitmap for storing marking wavefront:
874 _verification_bit_map->clear();
875
876 // Allocate temporary array for storing liveness data
877 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
878 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
879
880 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
881
882 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
883 // This verifies what application can see, since it only cares about reachable objects.
884 size_t count_reachable = 0;
885 if (ShenandoahVerifyLevel >= 2) {
886 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
887 _heap->workers()->run_task(&task);
888 count_reachable = task.processed();
889 }
890
891 log_debug(gc)("Safepoint verification finished getting initial reachable set");
892
893 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
894 // not the application, can see during the region scans. There is no reason to process the objects
895 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
896 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
897 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
898 // version
899
900 size_t count_marked = 0;
901 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
902 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
903 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
904 _heap->workers()->run_task(&task);
905 count_marked = task.processed();
906 } else {
907 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
908 }
909
910 log_debug(gc)("Safepoint verification finished walking marked objects");
911
912 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
913 // marked objects.
914
915 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
916 for (size_t i = 0; i < _heap->num_regions(); i++) {
917 ShenandoahHeapRegion* r = _heap->get_region(i);
918 if (generation != NULL && !generation->contains(r)) {
919 continue;
920 }
921
922 juint verf_live = 0;
923 if (r->is_humongous()) {
924 // For humongous objects, test if start region is marked live, and if so,
925 // all humongous regions in that chain have live data equal to their "used".
926 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
927 if (start_live > 0) {
928 verf_live = (juint)(r->used() / HeapWordSize);
929 }
930 } else {
931 verf_live = Atomic::load(&ld[r->index()]);
932 }
933
934 size_t reg_live = r->get_live_data_words();
935 if (reg_live != verf_live) {
936 stringStream ss;
937 r->print_on(&ss);
938 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
939 label, reg_live, verf_live, ss.freeze());
940 }
941 }
942 }
943
944 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
945
946
947 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
948 label, ShenandoahVerifyLevel, count_reachable, count_marked);
949
950 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
951 }
952
953 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
954 verify_at_safepoint(
955 "Generic Verification",
956 _verify_remembered_disable, // do not verify remembered set
957 _verify_forwarded_allow, // conservatively allow forwarded
958 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
959 _verify_cset_disable, // cset may be inconsistent
960 _verify_liveness_disable, // no reliable liveness data
961 _verify_regions_disable, // no reliable region data
962 _verify_gcstate_disable // no data about gcstate
963 );
964 }
965
966 void ShenandoahVerifier::verify_before_concmark() {
967 verify_at_safepoint(
968 "Before Mark",
969 _verify_remembered_for_marking, // verify read-only remembered set from bottom() to top()
970 _verify_forwarded_none, // UR should have fixed up
971 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
972 _verify_cset_none, // UR should have fixed this
973 _verify_liveness_disable, // no reliable liveness data
974 _verify_regions_notrash, // no trash regions
975 _verify_gcstate_stable // there are no forwarded objects
976 );
977 }
978
979 void ShenandoahVerifier::verify_after_concmark() {
980 verify_at_safepoint(
981 "After Mark",
982 _verify_remembered_disable, // do not verify remembered set
983 _verify_forwarded_none, // no forwarded references
984 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
985 _verify_cset_none, // no references to cset anymore
986 _verify_liveness_complete, // liveness data must be complete here
987 _verify_regions_disable, // trash regions not yet recycled
988 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
989 );
990 }
991
992 void ShenandoahVerifier::verify_before_evacuation() {
993 verify_at_safepoint(
994 "Before Evacuation",
995 _verify_remembered_disable, // do not verify remembered set
996 _verify_forwarded_none, // no forwarded references
997 _verify_marked_complete_except_references, // walk over marked objects too
998 _verify_cset_disable, // non-forwarded references to cset expected
999 _verify_liveness_complete, // liveness data must be complete here
1000 _verify_regions_disable, // trash regions not yet recycled
1001 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1002 );
1003 }
1004
1005 void ShenandoahVerifier::verify_during_evacuation() {
1006 verify_at_safepoint(
1007 "During Evacuation",
1008 _verify_remembered_disable, // do not verify remembered set
1009 _verify_forwarded_allow, // some forwarded references are allowed
1010 _verify_marked_disable, // walk only roots
1011 _verify_cset_disable, // some cset references are not forwarded yet
1012 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1013 _verify_regions_disable, // trash regions not yet recycled
1014 _verify_gcstate_evacuation // evacuation is in progress
1015 );
1016 }
1017
1018 void ShenandoahVerifier::verify_after_evacuation() {
1019 verify_at_safepoint(
1020 "After Evacuation",
1021 _verify_remembered_disable, // do not verify remembered set
1022 _verify_forwarded_allow, // objects are still forwarded
1023 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1024 _verify_cset_forwarded, // all cset refs are fully forwarded
1025 _verify_liveness_disable, // no reliable liveness data anymore
1026 _verify_regions_notrash, // trash regions have been recycled already
1027 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1028 );
1029 }
1030
1031 void ShenandoahVerifier::verify_before_updaterefs() {
1032 verify_at_safepoint(
1033 "Before Updating References",
1034 _verify_remembered_for_updating_references, // verify read-write remembered set
1035 _verify_forwarded_allow, // forwarded references allowed
1036 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1037 _verify_cset_forwarded, // all cset refs are fully forwarded
1038 _verify_liveness_disable, // no reliable liveness data anymore
1039 _verify_regions_notrash, // trash regions have been recycled already
1040 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1041 );
1042 }
1043
1044 void ShenandoahVerifier::verify_after_updaterefs() {
1045 verify_at_safepoint(
1046 "After Updating References",
1047 _verify_remembered_disable, // do not verify remembered set
1048 _verify_forwarded_none, // no forwarded references
1049 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1050 _verify_cset_none, // no cset references, all updated
1051 _verify_liveness_disable, // no reliable liveness data anymore
1052 _verify_regions_nocset, // no cset regions, trash regions have appeared
1053 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1054 );
1055 }
1056
1057 void ShenandoahVerifier::verify_after_degenerated() {
1058 verify_at_safepoint(
1059 "After Degenerated GC",
1060 _verify_remembered_disable, // do not verify remembered set
1061 _verify_forwarded_none, // all objects are non-forwarded
1062 _verify_marked_complete, // all objects are marked in complete bitmap
1063 _verify_cset_none, // no cset references
1064 _verify_liveness_disable, // no reliable liveness data anymore
1065 _verify_regions_notrash_nocset, // no trash, no cset
1066 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1067 );
1068 }
1069
1070 void ShenandoahVerifier::verify_before_fullgc() {
1071 verify_at_safepoint(
1072 "Before Full GC",
1073 _verify_remembered_disable, // do not verify remembered set
1074 _verify_forwarded_allow, // can have forwarded objects
1075 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1076 _verify_cset_disable, // cset might be foobared
1077 _verify_liveness_disable, // no reliable liveness data anymore
1078 _verify_regions_disable, // no reliable region data here
1079 _verify_gcstate_disable // no reliable gcstate data
1080 );
1081 }
1082
1083 void ShenandoahVerifier::verify_after_generational_fullgc() {
1084 verify_at_safepoint(
1085 "After Full Generational GC",
1086 _verify_remembered_after_full_gc, // verify read-write remembered set
1087 _verify_forwarded_none, // all objects are non-forwarded
1088 _verify_marked_complete, // all objects are marked in complete bitmap
1089 _verify_cset_none, // no cset references
1090 _verify_liveness_disable, // no reliable liveness data anymore
1091 _verify_regions_notrash_nocset, // no trash, no cset
1092 _verify_gcstate_stable // full gc cleaned up everything
1093 );
1094 }
1095
1096 void ShenandoahVerifier::verify_after_fullgc() {
1097 verify_at_safepoint(
1098 "After Full GC",
1099 _verify_remembered_disable, // do not verify remembered set
1100 _verify_forwarded_none, // all objects are non-forwarded
1101 _verify_marked_complete, // all objects are marked in complete bitmap
1102 _verify_cset_none, // no cset references
1103 _verify_liveness_disable, // no reliable liveness data anymore
1104 _verify_regions_notrash_nocset, // no trash, no cset
1105 _verify_gcstate_stable // full gc cleaned up everything
1106 );
1107 }
1108
1109 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1110 private:
1111 template <class T>
1112 void do_oop_work(T* p) {
1113 T o = RawAccess<>::oop_load(p);
1114 if (!CompressedOops::is_null(o)) {
1115 oop obj = CompressedOops::decode_not_null(o);
1116 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1117 if (obj != fwd) {
1118 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1119 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1120 }
1121 }
1122 }
1123
1124 public:
1125 void do_oop(narrowOop* p) { do_oop_work(p); }
1126 void do_oop(oop* p) { do_oop_work(p); }
1127 };
1128
1129 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1130 private:
1131 template <class T>
1132 void do_oop_work(T* p) {
1133 T o = RawAccess<>::oop_load(p);
1134 if (!CompressedOops::is_null(o)) {
1135 oop obj = CompressedOops::decode_not_null(o);
1136 ShenandoahHeap* heap = ShenandoahHeap::heap();
1137
1138 if (!heap->marking_context()->is_marked_or_old(obj)) {
1139 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1140 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1141 }
1142
1143 if (heap->in_collection_set(obj)) {
1144 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1145 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1146 }
1147
1148 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1149 if (obj != fwd) {
1150 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1151 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1152 }
1153 }
1154 }
1155
1156 public:
1157 void do_oop(narrowOop* p) { do_oop_work(p); }
1158 void do_oop(oop* p) { do_oop_work(p); }
1159 };
1160
1161 void ShenandoahVerifier::verify_roots_in_to_space() {
1162 ShenandoahVerifyInToSpaceClosure cl;
1163 ShenandoahRootVerifier::roots_do(&cl);
1164 }
1165
1166 void ShenandoahVerifier::verify_roots_no_forwarded() {
1167 ShenandoahVerifyNoForwared cl;
1168 ShenandoahRootVerifier::roots_do(&cl);
1169 }