1 /*
2 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23 #include "precompiled.hpp"
24
25 #include "gc/shenandoah/brooksPointer.hpp"
26 #include "gc/shenandoah/shenandoahConnectionMatrix.hpp"
27 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
28 #include "gc/shenandoah/shenandoahHeap.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
31 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
32 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
33 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
34 #include "gc/shenandoah/shenandoahVerifier.hpp"
35 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
36 #include "memory/allocation.hpp"
37
38 class ShenandoahVerifyOopClosure : public ExtendedOopClosure {
39 private:
40 const char* _phase;
41 ShenandoahVerifier::VerifyOptions _options;
42 ShenandoahVerifierStack* _stack;
43 ShenandoahHeap* _heap;
44 MarkBitMap* _map;
45 ShenandoahLivenessData* _ld;
46 void* _interior_loc;
47 oop _loc;
48
49 public:
50 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
51 const char* phase, ShenandoahVerifier::VerifyOptions options) :
52 _stack(stack), _heap(ShenandoahHeap::heap()), _map(map), _ld(ld), _loc(NULL), _interior_loc(NULL),
53 _phase(phase), _options(options) {};
54
55 private:
56 void print_obj(ShenandoahMessageBuffer& msg, oop obj) {
57 ShenandoahHeapRegion *r = _heap->heap_region_containing(obj);
58 stringStream ss;
59 r->print_on(&ss);
60
61 msg.append(" " PTR_FORMAT " - klass " PTR_FORMAT " %s\n", p2i(obj), p2i(obj->klass()), obj->klass()->external_name());
62 msg.append(" %3s allocated after complete mark start\n", _heap->allocated_after_complete_mark_start((HeapWord *) obj) ? "" : "not");
63 msg.append(" %3s allocated after next mark start\n", _heap->allocated_after_next_mark_start((HeapWord *) obj) ? "" : "not");
64 msg.append(" %3s marked complete\n", _heap->is_marked_complete(obj) ? "" : "not");
65 msg.append(" %3s marked next\n", _heap->is_marked_next(obj) ? "" : "not");
66 msg.append(" %3s in collection set\n", _heap->in_collection_set(obj) ? "" : "not");
67 msg.append(" region: %s", ss.as_string());
68 }
69
70 void print_non_obj(ShenandoahMessageBuffer& msg, void* loc) {
71 msg.append(" outside of Java heap\n");
72 stringStream ss;
73 os::print_location(&ss, (intptr_t) loc, false);
74 msg.append(" %s\n", ss.as_string());
75 }
76
77 void print_obj_safe(ShenandoahMessageBuffer& msg, void* loc) {
78 msg.append(" " PTR_FORMAT " - safe print, no details\n", p2i(loc));
79 if (_heap->is_in(loc)) {
80 ShenandoahHeapRegion* r = _heap->heap_region_containing(loc);
81 if (r != NULL) {
82 stringStream ss;
83 r->print_on(&ss);
84 msg.append(" region: %s", ss.as_string());
85 }
86 }
87 }
88
89 enum SafeLevel {
90 _safe_unknown,
91 _safe_oop,
92 _safe_oop_fwd,
93 _safe_all,
94 };
95
96 void print_failure(SafeLevel level, oop obj, const char* label) {
97 ResourceMark rm;
98
99 bool loc_in_heap = (_loc != NULL && _heap->is_in(_loc));
100 bool interior_loc_in_heap = (_interior_loc != NULL && _heap->is_in(_interior_loc));
101
102 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
103
104 msg.append("Referenced from:\n");
105 if (_interior_loc != NULL) {
106 msg.append(" interior location: " PTR_FORMAT "\n", p2i(_interior_loc));
107 if (loc_in_heap) {
108 print_obj(msg, _loc);
109 } else {
110 print_non_obj(msg, _interior_loc);
111 }
112 } else {
113 msg.append(" no location recorded, probably a plain heap scan\n");
114 }
115 msg.append("\n");
116
117 msg.append("Object:\n");
118 if (level >= _safe_oop) {
119 print_obj(msg, obj);
120 } else {
121 print_obj_safe(msg, obj);
122 }
123 msg.append("\n");
124
125 if (level >= _safe_oop) {
126 oop fwd = (oop) BrooksPointer::get_raw(obj);
127 if (!oopDesc::unsafe_equals(obj, fwd)) {
128 msg.append("Forwardee:\n");
129 if (level >= _safe_oop_fwd) {
130 print_obj(msg, fwd);
131 } else {
132 print_obj_safe(msg, fwd);
133 }
134 msg.append("\n");
135 }
136 }
137
138 if (level >= _safe_oop_fwd) {
139 oop fwd = (oop) BrooksPointer::get_raw(obj);
140 oop fwd2 = (oop) BrooksPointer::get_raw(fwd);
141 if (!oopDesc::unsafe_equals(fwd, fwd2)) {
142 msg.append("Second forwardee:\n");
143 print_obj_safe(msg, fwd2);
144 msg.append("\n");
145 }
146 }
147
148 if (loc_in_heap && UseShenandoahMatrix && (level == _safe_all)) {
149 msg.append("Matrix connections:\n");
150
151 oop fwd_to = (oop) BrooksPointer::get_raw(obj);
152 oop fwd_from = (oop) BrooksPointer::get_raw(_loc);
153
154 size_t from_idx = _heap->heap_region_index_containing(_loc);
155 size_t to_idx = _heap->heap_region_index_containing(obj);
156 size_t fwd_from_idx = _heap->heap_region_index_containing(fwd_from);
157 size_t fwd_to_idx = _heap->heap_region_index_containing(fwd_to);
158
159 ShenandoahConnectionMatrix* matrix = _heap->connection_matrix();
160 msg.append(" %35s %3s connected\n",
161 "reference and object",
162 matrix->is_connected(from_idx, to_idx) ? "" : "not");
163 msg.append(" %35s %3s connected\n",
164 "fwd(reference) and object",
165 matrix->is_connected(fwd_from_idx, to_idx) ? "" : "not");
166 msg.append(" %35s %3s connected\n",
167 "reference and fwd(object)",
168 matrix->is_connected(from_idx, fwd_to_idx) ? "" : "not");
169 msg.append(" %35s %3s connected\n",
170 "fwd(reference) and fwd(object)",
171 matrix->is_connected(fwd_from_idx, fwd_to_idx) ? "" : "not");
172
173 if (interior_loc_in_heap) {
174 size_t from_interior_idx = _heap->heap_region_index_containing(_interior_loc);
175 msg.append(" %35s %3s connected\n",
176 "interior-reference and object",
177 matrix->is_connected(from_interior_idx, to_idx) ? "" : "not");
178 msg.append(" %35s %3s connected\n",
179 "interior-reference and fwd(object)",
180 matrix->is_connected(from_interior_idx, fwd_to_idx) ? "" : "not");
181 }
182 }
183
184 report_vm_error(__FILE__, __LINE__, msg.buffer());
185 }
186
187 void verify(SafeLevel level, oop obj, bool test, const char* label) {
188 if (!test) {
189 print_failure(level, obj, label);
190 }
191 }
192
193 template <class T>
194 void do_oop_work(T* p) {
195 T o = oopDesc::load_heap_oop(p);
196 if (!oopDesc::is_null(o)) {
197 oop obj = oopDesc::decode_heap_oop_not_null(o);
198
199 // Single threaded verification can use faster non-atomic stack and bitmap
200 // methods.
201 //
202 // For performance reasons, only fully verify non-marked field values.
203 // We are here when the host object for *p is already marked. If field value
204 // is marked already, then we have to verify the matrix connection between
205 // host object and field value, regardless.
206
207 HeapWord* addr = (HeapWord*) obj;
208 if (_map->parMark(addr)) {
209 verify_oop_at(p, obj);
210 _stack->push(ShenandoahVerifierTask(obj));
211 } else {
212 verify_matrix(p, obj);
213 }
214 }
215 }
216
217 void verify_oop(oop obj) {
218 // Perform consistency checks with gradually decreasing safety level. This guarantees
219 // that failure report would not try to touch something that was not yet verified to be
220 // safe to process.
221
222 verify(_safe_unknown, obj, _heap->is_in(obj),
223 "oop must be in heap");
224 verify(_safe_unknown, obj, check_obj_alignment(obj),
225 "oop must be aligned");
226
227 // Verify that obj is not in dead space:
228 {
229 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
230
231 HeapWord *obj_addr = (HeapWord *) obj;
232 verify(_safe_unknown, obj, obj_addr < obj_reg->top(),
233 "Object start should be within the region");
234
235 if (!obj_reg->is_humongous()) {
236 verify(_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
237 "Object end should be within the region");
238 } else {
239 size_t humongous_start = obj_reg->region_number();
240 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
241 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
242 verify(_safe_unknown, obj, _heap->regions()->get(idx)->is_humongous_continuation(),
243 "Humongous object is in continuation that fits it");
244 }
245 }
246
247 verify(_safe_unknown, obj, Metaspace::contains(obj->klass()),
248 "klass pointer must go to metaspace");
249
250 // ------------ obj is safe at this point --------------
251
252 verify(_safe_oop, obj, obj_reg->is_active(),
253 "Object should be in active region");
254
255 switch (_options._verify_liveness) {
256 case ShenandoahVerifier::_verify_liveness_disable:
257 // skip
258 break;
259 case ShenandoahVerifier::_verify_liveness_complete:
260 Atomic::add(obj->size() + BrooksPointer::word_size(), &_ld[obj_reg->region_number()]);
261 // fallthrough for fast failure for un-live regions:
262 case ShenandoahVerifier::_verify_liveness_conservative:
263 verify(_safe_oop, obj, obj_reg->has_live(),
264 "Object must belong to region with live data");
265 break;
266 default:
267 assert(false, "Unhandled liveness verification");
268 }
269 }
270
271 oop fwd = (oop) BrooksPointer::get_raw(obj);
272 if (!oopDesc::unsafe_equals(obj, fwd)) {
273 verify(_safe_oop, obj, _heap->is_in(fwd),
274 "Forwardee must be in heap");
275 verify(_safe_oop, obj, !oopDesc::is_null(fwd),
276 "Forwardee is set");
277 verify(_safe_oop, obj, check_obj_alignment(fwd),
278 "Forwardee must be aligned");
279
280 // Verify that forwardee is not in the dead space:
281 if (!oopDesc::unsafe_equals(obj, fwd)) {
282 ShenandoahHeapRegion *fwd_reg = _heap->heap_region_containing(fwd);
283 verify(_safe_oop, obj, !fwd_reg->is_humongous(),
284 "Should have no humongous forwardees");
285
286 HeapWord *fwd_addr = (HeapWord *) fwd;
287 verify(_safe_oop, obj, fwd_addr < fwd_reg->top(),
288 "Forwardee start should be within the region");
289 verify(_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
290 "Forwardee end should be within the region");
291 }
292
293 verify(_safe_oop, obj, Metaspace::contains(fwd->klass()),
294 "Forwardee klass pointer must go to metaspace");
295 verify(_safe_oop, obj, obj->klass() == fwd->klass(),
296 "Forwardee klass pointer must go to metaspace");
297
298 oop fwd2 = (oop) BrooksPointer::get_raw(fwd);
299 verify(_safe_oop, obj, oopDesc::unsafe_equals(fwd, fwd2),
300 "Double forwarding");
301 }
302
303 // ------------ obj and fwd are safe at this point --------------
304
305 switch (_options._verify_marked) {
306 case ShenandoahVerifier::_verify_marked_disable:
307 // skip
308 break;
309 case ShenandoahVerifier::_verify_marked_next:
310 verify(_safe_all, obj, _heap->is_marked_next(obj),
311 "Must be marked in next bitmap");
312 break;
313 case ShenandoahVerifier::_verify_marked_complete:
314 verify(_safe_all, obj, _heap->is_marked_complete(obj),
315 "Must be marked in complete bitmap");
316 break;
317 default:
318 assert(false, "Unhandled mark verification");
319 }
320
321 switch (_options._verify_forwarded) {
322 case ShenandoahVerifier::_verify_forwarded_disable:
323 // skip
324 break;
325 case ShenandoahVerifier::_verify_forwarded_none: {
326 verify(_safe_all, obj, oopDesc::unsafe_equals(obj, fwd),
327 "Should not be forwarded");
328 break;
329 }
330 case ShenandoahVerifier::_verify_forwarded_allow: {
331 if (!oopDesc::unsafe_equals(obj, fwd)) {
332 verify(_safe_all, obj, _heap->heap_region_containing(obj) != _heap->heap_region_containing(fwd),
333 "Forwardee should be in another region");
334 }
335 break;
336 }
337 default:
338 assert(false, "Unhandled forwarding verification");
339 }
340
341 switch (_options._verify_cset) {
342 case ShenandoahVerifier::_verify_cset_disable:
343 // skip
344 break;
345 case ShenandoahVerifier::_verify_cset_none:
346 verify(_safe_all, obj, !_heap->in_collection_set(obj),
347 "Should not have references to collection set");
348 break;
349 case ShenandoahVerifier::_verify_cset_forwarded:
350 if (_heap->in_collection_set(obj)) {
351 verify(_safe_all, obj, !oopDesc::unsafe_equals(obj, fwd),
352 "Object in collection set, should have forwardee");
353 }
354 break;
355 default:
356 assert(false, "Unhandled cset verification");
357 }
358
359 verify_matrix(_interior_loc, obj);
360 }
361
362 void verify_matrix(void* interior, oop obj) {
363 if (!UseShenandoahMatrix || !_heap->is_in(interior)) return;
364 switch (_options._verify_matrix) {
365 case ShenandoahVerifier::_verify_matrix_conservative: {
366 size_t from_idx = _heap->heap_region_index_containing(interior);
367 size_t to_idx = _heap->heap_region_index_containing(obj);
368 _interior_loc = interior;
369 verify(_safe_all, obj, _heap->connection_matrix()->is_connected(from_idx, to_idx),
370 "Must be connected");
371 _interior_loc = NULL;
372 break;
373 }
374 case ShenandoahVerifier::_verify_matrix_disable:
375 break;
376 default:
377 assert(false, "Unhandled matrix verification");
378 }
379 }
380
381 public:
382
383 /**
384 * Verify object with known interior reference.
385 * @param p interior reference where the object is referenced from; can be off-heap
386 * @param obj verified object
387 */
388 template <class T>
389 void verify_oop_at(T* p, oop obj) {
390 _interior_loc = p;
391 verify_oop(obj);
392 _interior_loc = NULL;
393 }
394
395 /**
396 * Verify object without known interior reference.
397 * Useful when picking up the object at known offset in heap,
398 * but without knowing what objects reference it.
399 * @param obj verified object
400 */
401 void verify_oop_standalone(oop obj) {
402 _interior_loc = NULL;
403 verify_oop(obj);
404 _interior_loc = NULL;
405 }
406
407 /**
408 * Verify oop fields from this object.
409 * @param obj host object for verified fields
410 */
411 void verify_oops_from(oop obj) {
412 _loc = obj;
413 obj->oop_iterate(this);
414 _loc = NULL;
415 }
416
417 void do_oop(oop* p) { do_oop_work(p); }
418 void do_oop(narrowOop* p) { do_oop_work(p); }
419 };
420
421 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
422 private:
423 size_t _used, _committed, _garbage;
424 public:
425 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
426
427 bool heap_region_do(ShenandoahHeapRegion* r) {
428 _used += r->used();
429 _garbage += r->garbage();
430 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
431 return false;
432 }
433
434 size_t used() { return _used; }
435 size_t committed() { return _committed; }
436 size_t garbage() { return _garbage; }
437 };
438
439 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
440 private:
441 ShenandoahHeap* _heap;
442 const char* _phase;
443 ShenandoahVerifier::VerifyRegions _regions;
444 public:
445 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
446 _heap(ShenandoahHeap::heap()), _regions(regions), _phase(phase) {};
447
448 void print_failure(ShenandoahHeapRegion* r, const char* label) {
449 ResourceMark rm;
450
451 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
452
453 stringStream ss;
454 r->print_on(&ss);
455 msg.append("%s", ss.as_string());
456
457 report_vm_error(__FILE__, __LINE__, msg.buffer());
458 }
459
460 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
461 if (!test) {
462 print_failure(r, msg);
463 }
464 }
465
466 bool heap_region_do(ShenandoahHeapRegion* r) {
467 switch (_regions) {
468 case ShenandoahVerifier::_verify_regions_disable:
469 break;
470 case ShenandoahVerifier::_verify_regions_notrash:
471 verify(r, !r->is_trash(),
472 "Should not have trash regions");
473 break;
474 case ShenandoahVerifier::_verify_regions_nocset:
475 verify(r, !r->is_cset(),
476 "Should not have cset regions");
477 break;
478 case ShenandoahVerifier::_verify_regions_notrash_nocset:
479 verify(r, !r->is_trash(),
480 "Should not have trash regions");
481 verify(r, !r->is_cset(),
482 "Should not have cset regions");
483 break;
484 default:
485 ShouldNotReachHere();
486 }
487
488 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
489 "Capacity should match region size");
490
491 verify(r, r->bottom() <= _heap->complete_top_at_mark_start(r->bottom()),
492 "Region top should not be less than bottom");
493
494 verify(r, _heap->complete_top_at_mark_start(r->bottom()) <= r->top(),
495 "Complete TAMS should not be larger than top");
496
497 verify(r, r->get_live_data_bytes() <= r->capacity(),
498 "Live data cannot be larger than capacity");
499
500 verify(r, r->garbage() <= r->capacity(),
501 "Garbage cannot be larger than capacity");
502
503 verify(r, r->used() <= r->capacity(),
504 "Used cannot be larger than capacity");
505
506 verify(r, r->get_shared_allocs() <= r->capacity(),
507 "Shared alloc count should not be larger than capacity");
508
509 verify(r, r->get_tlab_allocs() <= r->capacity(),
510 "TLAB alloc count should not be larger than capacity");
511
512 verify(r, r->get_gclab_allocs() <= r->capacity(),
513 "GCLAB alloc count should not be larger than capacity");
514
515 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
516 "Accurate accounting: shared + TLAB + GCLAB = used");
517
518 verify(r, !r->is_empty() || !r->has_live(),
519 "Empty regions should not have live data");
520
521 verify(r, r->is_cset() == r->in_collection_set(),
522 "Transitional: region flags and collection set agree");
523
524 verify(r, r->is_empty() || r->first_alloc_seq_num() != 0,
525 "Non-empty regions should have first timestamp set");
526
527 verify(r, r->is_empty() || r->last_alloc_seq_num() != 0,
528 "Non-empty regions should have last timestamp set");
529
530 verify(r, r->first_alloc_seq_num() <= r->last_alloc_seq_num(),
531 "First timestamp should not be greater than last timestamp");
532
533 return false;
534 }
535 };
536
537 class ShenandoahVerifierReachableTask : public AbstractGangTask {
538 private:
539 const char* _label;
540 ShenandoahRootProcessor* _rp;
541 ShenandoahVerifier::VerifyOptions _options;
542 ShenandoahHeap* _heap;
543 ShenandoahLivenessData* _ld;
544 MarkBitMap* _bitmap;
545 volatile size_t _processed;
546
547 public:
548 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
549 ShenandoahLivenessData* ld,
550 ShenandoahRootProcessor* rp,
551 const char* label,
552 ShenandoahVerifier::VerifyOptions options) :
553 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
554 _heap(ShenandoahHeap::heap()), _rp(rp), _ld(ld), _bitmap(bitmap), _processed(0),
555 _label(label), _options(options) {};
556
557 size_t processed() {
558 return _processed;
559 }
560
561 virtual void work(uint worker_id) {
562 ResourceMark rm;
563 ShenandoahVerifierStack stack;
564
565 // On level 2, we need to only check the roots once.
566 // On level 3, we want to check the roots, and seed the local stack.
567 // It is a lesser evil to accept multiple root scans at level 3, because
568 // extended parallelism would buy us out.
569 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
570 || (ShenandoahVerifyLevel >= 3)) {
571 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
572 ShenandoahMessageBuffer("%s, Roots", _label),
573 _options);
574 _rp->process_all_roots_slow(&cl);
575 }
576
577 size_t processed = 0;
578
579 if (ShenandoahVerifyLevel >= 3) {
580 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
581 ShenandoahMessageBuffer("%s, Reachable", _label),
582 _options);
583 while (!stack.is_empty()) {
584 processed++;
585 ShenandoahVerifierTask task = stack.pop();
586 cl.verify_oops_from(task.obj());
587 }
588 }
589
590 Atomic::add(processed, &_processed);
591 }
592 };
593
594 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
595 private:
596 const char* _label;
597 ShenandoahVerifier::VerifyOptions _options;
598 ShenandoahHeap *_heap;
599 ShenandoahHeapRegionSet* _regions;
600 MarkBitMap* _bitmap;
601 ShenandoahLivenessData* _ld;
602 volatile size_t _claimed;
603 volatile size_t _processed;
604
605 public:
606 ShenandoahVerifierMarkedRegionTask(ShenandoahHeapRegionSet* regions, MarkBitMap* bitmap,
607 ShenandoahLivenessData* ld,
608 const char* label,
609 ShenandoahVerifier::VerifyOptions options) :
610 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
611 _heap(ShenandoahHeap::heap()), _regions(regions), _ld(ld), _bitmap(bitmap), _claimed(0), _processed(0),
612 _label(label), _options(options) {};
613
614 size_t processed() {
615 return _processed;
616 }
617
618 virtual void work(uint worker_id) {
619 ShenandoahVerifierStack stack;
620 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
621 ShenandoahMessageBuffer("%s, Marked", _label),
622 _options);
623
624 while (true) {
625 size_t v = Atomic::add(1u, &_claimed) - 1;
626 if (v < _heap->num_regions()) {
627 ShenandoahHeapRegion* r = _regions->get(v);
628 if (!r->is_humongous() && !r->is_trash()) {
629 work_regular(r, stack, cl);
630 } else if (r->is_humongous_start()) {
631 work_humongous(r, stack, cl);
632 }
633 } else {
634 break;
635 }
636 }
637 }
638
639 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
640 size_t processed = 0;
641 HeapWord* obj = r->bottom() + BrooksPointer::word_size();
642 if (_heap->is_marked_complete((oop)obj)) {
643 verify_and_follow(obj, stack, cl, &processed);
644 }
645 Atomic::add(processed, &_processed);
646 }
647
648 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
649 size_t processed = 0;
650 MarkBitMap* mark_bit_map = _heap->complete_mark_bit_map();
651 HeapWord* tams = _heap->complete_top_at_mark_start(r->bottom());
652
653 // Bitmaps, before TAMS
654 if (tams > r->bottom()) {
655 HeapWord* start = r->bottom() + BrooksPointer::word_size();
656 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
657
658 while (addr < tams) {
659 verify_and_follow(addr, stack, cl, &processed);
660 addr += BrooksPointer::word_size();
661 if (addr < tams) {
662 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
663 }
664 }
665 }
666
667 // Size-based, after TAMS
668 {
669 HeapWord* limit = r->top();
670 HeapWord* addr = tams + BrooksPointer::word_size();
671
672 while (addr < limit) {
673 verify_and_follow(addr, stack, cl, &processed);
674 addr += oop(addr)->size() + BrooksPointer::word_size();
675 }
676 }
677
678 Atomic::add(processed, &_processed);
679 }
680
681 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
682 if (!_bitmap->parMark(addr)) return;
683
684 // Verify the object itself:
685 oop obj = oop(addr);
686 cl.verify_oop_standalone(obj);
687
688 // Verify everything reachable from that object too, hopefully realizing
689 // everything was already marked, and never touching further:
690 cl.verify_oops_from(obj);
691 (*processed)++;
692
693 while (!stack.is_empty()) {
694 ShenandoahVerifierTask task = stack.pop();
695 cl.verify_oops_from(task.obj());
696 (*processed)++;
697 }
698 }
699 };
700
701 void ShenandoahVerifier::verify_at_safepoint(const char *label,
702 VerifyForwarded forwarded, VerifyMarked marked,
703 VerifyMatrix matrix, VerifyCollectionSet cset,
704 VerifyLiveness liveness, VerifyRegions regions) {
705 guarantee(SafepointSynchronize::is_at_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 // Heap size checks
714 {
715 ShenandoahHeapLocker lock(_heap->lock());
716
717 ShenandoahCalculateRegionStatsClosure cl;
718 _heap->heap_region_iterate(&cl);
719 size_t heap_used = _heap->used();
720 guarantee(cl.used() == heap_used,
721 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
722 label, heap_used/K, cl.used()/K);
723
724 size_t heap_committed = _heap->committed();
725 guarantee(cl.committed() == heap_committed,
726 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
727 label, heap_committed/K, cl.committed()/K);
728 }
729
730 // Internal heap region checks
731 if (ShenandoahVerifyLevel >= 1) {
732 ShenandoahVerifyHeapRegionClosure cl(label, regions);
733 _heap->heap_region_iterate(&cl,
734 /* skip_cset = */ false,
735 /* skip_humongous_cont = */ false);
736 }
737
738 OrderAccess::fence();
739 _heap->ensure_parsability(false);
740
741 // Allocate temporary bitmap for storing marking wavefront:
742 MemRegion mr = MemRegion(_verification_bit_map->startWord(), _verification_bit_map->endWord());
743 _verification_bit_map->clear_range_large(mr);
744
745 // Allocate temporary array for storing liveness data
746 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
747 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
748
749 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, matrix, cset, liveness, regions);
750
751 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
752 // This verifies what application can see, since it only cares about reachable objects.
753 size_t count_reachable = 0;
754 if (ShenandoahVerifyLevel >= 2) {
755 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
756 ShenandoahPhaseTimings::_num_phases); // no need for stats
757
758 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
759 _heap->workers()->run_task(&task);
760 count_reachable = task.processed();
761 }
762
763 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
764 // not the application, can see during the region scans. There is no reason to process the objects
765 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
766 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
767 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
768 // version
769
770 size_t count_marked = 0;
771 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
772 ShenandoahVerifierMarkedRegionTask task(_heap->regions(), _verification_bit_map, ld, label, options);
773 _heap->workers()->run_task(&task);
774 count_marked = task.processed();
775 } else {
776 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_next || marked == _verify_marked_disable, "Should be");
777 }
778
779 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
780 // marked objects.
781
782 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
783 ShenandoahHeapRegionSet* set = _heap->regions();
784 for (size_t i = 0; i < _heap->num_regions(); i++) {
785 ShenandoahHeapRegion* r = set->get(i);
786
787 juint verf_live = 0;
788 if (r->is_humongous()) {
789 // For humongous objects, test if start region is marked live, and if so,
790 // all humongous regions in that chain have live data equal to their "used".
791 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
792 if (start_live > 0) {
793 verf_live = (juint)(r->used() / HeapWordSize);
794 }
795 } else {
796 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
797 }
798
799 size_t reg_live = r->get_live_data_words();
800 if (reg_live != verf_live) {
801 ResourceMark rm;
802 stringStream ss;
803 r->print_on(&ss);
804 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
805 label, reg_live, verf_live, ss.as_string());
806 }
807 }
808 }
809
810 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
811 label, ShenandoahVerifyLevel, count_reachable, count_marked);
812
813 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
814 }
815
816 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
817 verify_at_safepoint(
818 "Generic Verification",
819 _verify_forwarded_allow, // conservatively allow forwarded
820 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
821 _verify_matrix_disable, // matrix can be inconsistent here
822 _verify_cset_disable, // cset may be inconsistent
823 _verify_liveness_disable, // no reliable liveness data
824 _verify_regions_disable // no reliable region data
825 );
826 }
827
828 void ShenandoahVerifier::verify_before_concmark() {
829 if (_heap->need_update_refs()) {
830 verify_at_safepoint(
831 "Before Mark",
832 _verify_forwarded_allow, // may have forwarded references
833 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
834 _verify_matrix_disable, // matrix is foobared
835 _verify_cset_forwarded, // allow forwarded references to cset
836 _verify_liveness_disable, // no reliable liveness data
837 _verify_regions_notrash // no trash regions
838 );
839 } else {
840 verify_at_safepoint(
841 "Before Mark",
842 _verify_forwarded_none, // UR should have fixed up
843 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
844 _verify_matrix_conservative, // UR should have fixed matrix
845 _verify_cset_none, // UR should have fixed this
846 _verify_liveness_disable, // no reliable liveness data
847 _verify_regions_notrash // no trash regions
848 );
849 }
850 }
851
852 void ShenandoahVerifier::verify_after_concmark() {
853 verify_at_safepoint(
854 "After Mark",
855 _verify_forwarded_none, // no forwarded references
856 _verify_marked_complete, // bitmaps as precise as we can get
857 _verify_matrix_disable, // matrix might be foobared
858 _verify_cset_none, // no references to cset anymore
859 _verify_liveness_complete, // liveness data must be complete here
860 _verify_regions_disable // trash regions not yet recycled
861 );
862 }
863
864 void ShenandoahVerifier::verify_before_evacuation() {
865 // Evacuation is always preceded by mark, but we want to have a sanity check after
866 // selecting the collection set, and (immediate) regions recycling
867 verify_at_safepoint(
868 "Before Evacuation",
869 _verify_forwarded_none, // no forwarded references
870 _verify_marked_complete, // walk over marked objects too
871 _verify_matrix_disable, // skip, verified after mark
872 _verify_cset_disable, // skip, verified after mark
873 _verify_liveness_disable, // skip, verified after mark
874 _verify_regions_disable // trash regions not yet recycled
875 );
876 }
877
878 void ShenandoahVerifier::verify_after_evacuation() {
879 verify_at_safepoint(
880 "After Evacuation",
881 _verify_forwarded_allow, // objects are still forwarded
882 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
883 _verify_matrix_disable, // matrix is inconsistent here
884 _verify_cset_forwarded, // all cset refs are fully forwarded
885 _verify_liveness_disable, // no reliable liveness data anymore
886 _verify_regions_notrash // trash regions have been recycled already
887 );
888 }
889
890 void ShenandoahVerifier::verify_before_updaterefs() {
891 verify_at_safepoint(
892 "Before Updating References",
893 _verify_forwarded_allow, // forwarded references allowed
894 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
895 _verify_matrix_disable, // matrix is inconsistent here
896 _verify_cset_forwarded, // all cset refs are fully forwarded
897 _verify_liveness_disable, // no reliable liveness data anymore
898 _verify_regions_notrash // trash regions have been recycled already
899 );
900 }
901
902 void ShenandoahVerifier::verify_after_updaterefs() {
903 verify_at_safepoint(
904 "After Updating References",
905 _verify_forwarded_none, // no forwarded references
906 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
907 _verify_matrix_conservative, // matrix is conservatively consistent
908 _verify_cset_none, // no cset references, all updated
909 _verify_liveness_disable, // no reliable liveness data anymore
910 _verify_regions_nocset // no cset regions, trash regions have appeared
911 );
912 }
913
914 void ShenandoahVerifier::verify_before_partial() {
915 verify_at_safepoint(
916 "Before Partial GC",
917 _verify_forwarded_none, // cannot have forwarded objects
918 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
919 _verify_matrix_conservative, // matrix is conservatively consistent
920 _verify_cset_none, // no cset references before partial
921 _verify_liveness_disable, // no reliable liveness data anymore
922 _verify_regions_notrash_nocset // no trash and no cset regions
923 );
924 }
925
926 void ShenandoahVerifier::verify_after_partial() {
927 verify_at_safepoint(
928 "After Partial GC",
929 _verify_forwarded_none, // cannot have forwarded objects
930 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
931 _verify_matrix_conservative, // matrix is conservatively consistent
932 _verify_cset_none, // no cset references left after partial
933 _verify_liveness_disable, // no reliable liveness data anymore
934 _verify_regions_nocset // no cset regions, trash regions allowed
935 );
936 }
937
938 void ShenandoahVerifier::verify_before_fullgc() {
939 verify_at_safepoint(
940 "Before Full GC",
941 _verify_forwarded_allow, // can have forwarded objects
942 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
943 _verify_matrix_disable, // matrix might be foobared
944 _verify_cset_disable, // cset might be foobared
945 _verify_liveness_disable, // no reliable liveness data anymore
946 _verify_regions_disable // no reliable region data here
947 );
948 }
949
950 void ShenandoahVerifier::verify_after_fullgc() {
951 verify_at_safepoint(
952 "After Full GC",
953 _verify_forwarded_none, // all objects are non-forwarded
954 _verify_marked_complete, // all objects are marked in complete bitmap
955 _verify_matrix_conservative, // matrix is conservatively consistent
956 _verify_cset_none, // no cset references
957 _verify_liveness_disable, // no reliable liveness data anymore
958 _verify_regions_notrash_nocset // no trash, no cset
959 );
960 }
961
962 void ShenandoahVerifier::verify_oop_fwdptr(oop obj, oop fwd) {
963 guarantee(UseShenandoahGC, "must only be called when Shenandoah is used");
964
965 ShenandoahHeap* heap = ShenandoahHeap::heap();
966
967 guarantee(obj != NULL, "oop is not NULL");
968 guarantee(heap->is_in(obj), "oop must point to a heap address: " PTR_FORMAT, p2i(obj));
969
970 guarantee(fwd != NULL, "forwardee is not NULL");
971 if (!heap->is_in(fwd)) {
972 ResourceMark rm;
973 ShenandoahHeapRegion* r = heap->heap_region_containing(obj);
974 stringStream obj_region;
975 r->print_on(&obj_region);
976
977 fatal("forwardee must point to a heap address: " PTR_FORMAT " -> " PTR_FORMAT "\n %s",
978 p2i(obj), p2i(fwd), obj_region.as_string());
979 }
980
981 if (!oopDesc::unsafe_equals(fwd, obj) &&
982 (heap->heap_region_containing(fwd) ==
983 heap->heap_region_containing(obj))) {
984 ResourceMark rm;
985 ShenandoahHeapRegion* ro = heap->heap_region_containing(obj);
986 stringStream obj_region;
987 ro->print_on(&obj_region);
988
989 ShenandoahHeapRegion* rf = heap->heap_region_containing(fwd);
990 stringStream fwd_region;
991 rf->print_on(&fwd_region);
992
993 fatal("forwardee should be self, or another region: " PTR_FORMAT " -> " PTR_FORMAT "\n %s %s",
994 p2i(obj), p2i(fwd),
995 obj_region.as_string(), fwd_region.as_string());
996 }
997
998 if (!oopDesc::unsafe_equals(obj, fwd)) {
999 oop fwd2 = oop(BrooksPointer::get_raw(fwd));
1000 if (!oopDesc::unsafe_equals(fwd, fwd2)) {
1001 // We should never be forwarded more than once.
1002 ResourceMark rm;
1003
1004 ShenandoahHeapRegion* ro = heap->heap_region_containing(obj);
1005 stringStream obj_region;
1006 ro->print_on(&obj_region);
1007
1008 ShenandoahHeapRegion* rf = heap->heap_region_containing(fwd);
1009 stringStream fwd_region;
1010 rf->print_on(&fwd_region);
1011
1012 ShenandoahHeapRegion* rf2 = heap->heap_region_containing(fwd2);
1013 stringStream fwd2_region;
1014 rf2->print_on(&fwd2_region);
1015
1016 fatal("Multiple forwardings: " PTR_FORMAT " -> " PTR_FORMAT " -> " PTR_FORMAT "\n %s %s %s",
1017 p2i(obj), p2i(fwd), p2i(fwd2),
1018 obj_region.as_string(), fwd_region.as_string(), fwd2_region.as_string());
1019 }
1020 }
1021 }
1022
1023 void ShenandoahVerifier::verify_oop(oop obj) {
1024 oop fwd = oop(BrooksPointer::get_raw(obj));
1025 verify_oop_fwdptr(obj, fwd);
1026 }