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 mark start\n", _heap->allocated_after_mark_start((HeapWord *) obj) ? "" : "not");
63 msg.append(" %3s marked\n", _heap->is_marked(obj) ? "" : "not");
64 msg.append(" %3s in collection set\n", _heap->in_collection_set(obj) ? "" : "not");
65 msg.append(" region: %s", ss.as_string());
66 }
67
68 void print_non_obj(ShenandoahMessageBuffer& msg, void* loc) {
69 msg.append(" outside of Java heap\n");
70 stringStream ss;
71 os::print_location(&ss, (intptr_t) loc, false);
72 msg.append(" %s\n", ss.as_string());
73 }
74
75 void print_obj_safe(ShenandoahMessageBuffer& msg, void* loc) {
76 msg.append(" " PTR_FORMAT " - safe print, no details\n", p2i(loc));
77 if (_heap->is_in(loc)) {
78 ShenandoahHeapRegion* r = _heap->heap_region_containing(loc);
79 if (r != NULL) {
80 stringStream ss;
81 r->print_on(&ss);
82 msg.append(" region: %s", ss.as_string());
83 }
84 }
85 }
86
87 enum SafeLevel {
88 _safe_unknown,
89 _safe_oop,
90 _safe_oop_fwd,
91 _safe_all,
92 };
93
94 void print_failure(SafeLevel level, oop obj, const char* label) {
95 ResourceMark rm;
96
97 bool loc_in_heap = (_loc != NULL && _heap->is_in(_loc));
98 bool interior_loc_in_heap = (_interior_loc != NULL && _heap->is_in(_interior_loc));
99
100 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
101
102 msg.append("Referenced from:\n");
103 if (_interior_loc != NULL) {
104 msg.append(" interior location: " PTR_FORMAT "\n", p2i(_interior_loc));
105 if (loc_in_heap) {
106 print_obj(msg, _loc);
107 } else {
108 print_non_obj(msg, _interior_loc);
109 }
110 } else {
111 msg.append(" no location recorded, probably a plain heap scan\n");
112 }
113 msg.append("\n");
114
115 msg.append("Object:\n");
116 if (level >= _safe_oop) {
117 print_obj(msg, obj);
118 } else {
119 print_obj_safe(msg, obj);
120 }
121 msg.append("\n");
122
123 if (level >= _safe_oop) {
124 oop fwd = (oop) BrooksPointer::get_raw(obj);
125 if (!oopDesc::unsafe_equals(obj, fwd)) {
126 msg.append("Forwardee:\n");
127 if (level >= _safe_oop_fwd) {
128 print_obj(msg, fwd);
129 } else {
130 print_obj_safe(msg, fwd);
131 }
132 msg.append("\n");
133 }
134 }
135
136 if (level >= _safe_oop_fwd) {
137 oop fwd = (oop) BrooksPointer::get_raw(obj);
138 oop fwd2 = (oop) BrooksPointer::get_raw(fwd);
139 if (!oopDesc::unsafe_equals(fwd, fwd2)) {
140 msg.append("Second forwardee:\n");
141 print_obj_safe(msg, fwd2);
142 msg.append("\n");
143 }
144 }
145
146 if (loc_in_heap && UseShenandoahMatrix && (level == _safe_all)) {
147 msg.append("Matrix connections:\n");
148
149 oop fwd_to = (oop) BrooksPointer::get_raw(obj);
150 oop fwd_from = (oop) BrooksPointer::get_raw(_loc);
151
152 size_t from_idx = _heap->heap_region_index_containing(_loc);
153 size_t to_idx = _heap->heap_region_index_containing(obj);
154 size_t fwd_from_idx = _heap->heap_region_index_containing(fwd_from);
155 size_t fwd_to_idx = _heap->heap_region_index_containing(fwd_to);
156
157 ShenandoahConnectionMatrix* matrix = _heap->connection_matrix();
158 msg.append(" %35s %3s connected\n",
159 "reference and object",
160 matrix->is_connected(from_idx, to_idx) ? "" : "not");
161 msg.append(" %35s %3s connected\n",
162 "fwd(reference) and object",
163 matrix->is_connected(fwd_from_idx, to_idx) ? "" : "not");
164 msg.append(" %35s %3s connected\n",
165 "reference and fwd(object)",
166 matrix->is_connected(from_idx, fwd_to_idx) ? "" : "not");
167 msg.append(" %35s %3s connected\n",
168 "fwd(reference) and fwd(object)",
169 matrix->is_connected(fwd_from_idx, fwd_to_idx) ? "" : "not");
170
171 if (interior_loc_in_heap) {
172 size_t from_interior_idx = _heap->heap_region_index_containing(_interior_loc);
173 msg.append(" %35s %3s connected\n",
174 "interior-reference and object",
175 matrix->is_connected(from_interior_idx, to_idx) ? "" : "not");
176 msg.append(" %35s %3s connected\n",
177 "interior-reference and fwd(object)",
178 matrix->is_connected(from_interior_idx, fwd_to_idx) ? "" : "not");
179 }
180 }
181
182 report_vm_error(__FILE__, __LINE__, msg.buffer());
183 }
184
185 void verify(SafeLevel level, oop obj, bool test, const char* label) {
186 if (!test) {
187 print_failure(level, obj, label);
188 }
189 }
190
191 template <class T>
192 void do_oop_work(T* p) {
193 T o = oopDesc::load_heap_oop(p);
194 if (!oopDesc::is_null(o)) {
195 oop obj = oopDesc::decode_heap_oop_not_null(o);
196
197 // Single threaded verification can use faster non-atomic stack and bitmap
198 // methods.
199 //
200 // For performance reasons, only fully verify non-marked field values.
201 // We are here when the host object for *p is already marked. If field value
202 // is marked already, then we have to verify the matrix connection between
203 // host object and field value, regardless.
204
205 HeapWord* addr = (HeapWord*) obj;
206 if (_map->parMark(addr)) {
207 verify_oop_at(p, obj);
208 _stack->push(ShenandoahVerifierTask(obj));
209 } else {
210 verify_matrix(p, obj);
211 }
212 }
213 }
214
215 void verify_oop(oop obj) {
216 // Perform consistency checks with gradually decreasing safety level. This guarantees
217 // that failure report would not try to touch something that was not yet verified to be
218 // safe to process.
219
220 verify(_safe_unknown, obj, _heap->is_in(obj),
221 "oop must be in heap");
222 verify(_safe_unknown, obj, check_obj_alignment(obj),
223 "oop must be aligned");
224
225 // Verify that obj is not in dead space:
226 {
227 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
228
229 HeapWord *obj_addr = (HeapWord *) obj;
230 verify(_safe_unknown, obj, obj_addr < obj_reg->top(),
231 "Object start should be within the region");
232
233 if (!obj_reg->is_humongous()) {
234 verify(_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
235 "Object end should be within the region");
236 } else {
237 size_t humongous_start = obj_reg->region_number();
238 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
239 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
240 verify(_safe_unknown, obj, _heap->regions()->get(idx)->is_humongous_continuation(),
241 "Humongous object is in continuation that fits it");
242 }
243 }
244
245 verify(_safe_unknown, obj, Metaspace::contains(obj->klass()),
246 "klass pointer must go to metaspace");
247
248 // ------------ obj is safe at this point --------------
249
250 verify(_safe_oop, obj, obj_reg->is_active(),
251 "Object should be in active region");
252
253 switch (_options._verify_liveness) {
254 case ShenandoahVerifier::_verify_liveness_disable:
255 // skip
256 break;
257 case ShenandoahVerifier::_verify_liveness_complete:
258 Atomic::add(obj->size() + BrooksPointer::word_size(), &_ld[obj_reg->region_number()]);
259 // fallthrough for fast failure for un-live regions:
260 case ShenandoahVerifier::_verify_liveness_conservative:
261 verify(_safe_oop, obj, obj_reg->has_live(),
262 "Object must belong to region with live data");
263 break;
264 default:
265 assert(false, "Unhandled liveness verification");
266 }
267 }
268
269 oop fwd = (oop) BrooksPointer::get_raw(obj);
270 if (!oopDesc::unsafe_equals(obj, fwd)) {
271 verify(_safe_oop, obj, _heap->is_in(fwd),
272 "Forwardee must be in heap");
273 verify(_safe_oop, obj, !oopDesc::is_null(fwd),
274 "Forwardee is set");
275 verify(_safe_oop, obj, check_obj_alignment(fwd),
276 "Forwardee must be aligned");
277
278 // Verify that forwardee is not in the dead space:
279 if (!oopDesc::unsafe_equals(obj, fwd)) {
280 ShenandoahHeapRegion *fwd_reg = _heap->heap_region_containing(fwd);
281 verify(_safe_oop, obj, !fwd_reg->is_humongous(),
282 "Should have no humongous forwardees");
283
284 HeapWord *fwd_addr = (HeapWord *) fwd;
285 verify(_safe_oop, obj, fwd_addr < fwd_reg->top(),
286 "Forwardee start should be within the region");
287 verify(_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
288 "Forwardee end should be within the region");
289 }
290
291 verify(_safe_oop, obj, Metaspace::contains(fwd->klass()),
292 "Forwardee klass pointer must go to metaspace");
293 verify(_safe_oop, obj, obj->klass() == fwd->klass(),
294 "Forwardee klass pointer must go to metaspace");
295
296 oop fwd2 = (oop) BrooksPointer::get_raw(fwd);
297 verify(_safe_oop, obj, oopDesc::unsafe_equals(fwd, fwd2),
298 "Double forwarding");
299 }
300
301 // ------------ obj and fwd are safe at this point --------------
302
303 switch (_options._verify_marked) {
304 case ShenandoahVerifier::_verify_marked_disable:
305 // skip
306 break;
307 case ShenandoahVerifier::_verify_marked:
308 verify(_safe_all, obj, _heap->is_marked(obj),
309 "Must be marked");
310 break;
311 default:
312 assert(false, "Unhandled mark verification");
313 }
314
315 switch (_options._verify_forwarded) {
316 case ShenandoahVerifier::_verify_forwarded_disable:
317 // skip
318 break;
319 case ShenandoahVerifier::_verify_forwarded_none: {
320 verify(_safe_all, obj, oopDesc::unsafe_equals(obj, fwd),
321 "Should not be forwarded");
322 break;
323 }
324 case ShenandoahVerifier::_verify_forwarded_allow: {
325 if (!oopDesc::unsafe_equals(obj, fwd)) {
326 verify(_safe_all, obj, _heap->heap_region_containing(obj) != _heap->heap_region_containing(fwd),
327 "Forwardee should be in another region");
328 }
329 break;
330 }
331 default:
332 assert(false, "Unhandled forwarding verification");
333 }
334
335 switch (_options._verify_cset) {
336 case ShenandoahVerifier::_verify_cset_disable:
337 // skip
338 break;
339 case ShenandoahVerifier::_verify_cset_none:
340 verify(_safe_all, obj, !_heap->in_collection_set(obj),
341 "Should not have references to collection set");
342 break;
343 case ShenandoahVerifier::_verify_cset_forwarded:
344 if (_heap->in_collection_set(obj)) {
345 verify(_safe_all, obj, !oopDesc::unsafe_equals(obj, fwd),
346 "Object in collection set, should have forwardee");
347 }
348 break;
349 default:
350 assert(false, "Unhandled cset verification");
351 }
352
353 verify_matrix(_interior_loc, obj);
354 }
355
356 void verify_matrix(void* interior, oop obj) {
357 if (!UseShenandoahMatrix || !_heap->is_in(interior)) return;
358 switch (_options._verify_matrix) {
359 case ShenandoahVerifier::_verify_matrix_conservative: {
360 size_t from_idx = _heap->heap_region_index_containing(interior);
361 size_t to_idx = _heap->heap_region_index_containing(obj);
362 _interior_loc = interior;
363 verify(_safe_all, obj, _heap->connection_matrix()->is_connected(from_idx, to_idx),
364 "Must be connected");
365 _interior_loc = NULL;
366 break;
367 }
368 case ShenandoahVerifier::_verify_matrix_disable:
369 break;
370 default:
371 assert(false, "Unhandled matrix verification");
372 }
373 }
374
375 public:
376
377 /**
378 * Verify object with known interior reference.
379 * @param p interior reference where the object is referenced from; can be off-heap
380 * @param obj verified object
381 */
382 template <class T>
383 void verify_oop_at(T* p, oop obj) {
384 _interior_loc = p;
385 verify_oop(obj);
386 _interior_loc = NULL;
387 }
388
389 /**
390 * Verify object without known interior reference.
391 * Useful when picking up the object at known offset in heap,
392 * but without knowing what objects reference it.
393 * @param obj verified object
394 */
395 void verify_oop_standalone(oop obj) {
396 _interior_loc = NULL;
397 verify_oop(obj);
398 _interior_loc = NULL;
399 }
400
401 /**
402 * Verify oop fields from this object.
403 * @param obj host object for verified fields
404 */
405 void verify_oops_from(oop obj) {
406 _loc = obj;
407 obj->oop_iterate(this);
408 _loc = NULL;
409 }
410
411 void do_oop(oop* p) { do_oop_work(p); }
412 void do_oop(narrowOop* p) { do_oop_work(p); }
413 };
414
415 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
416 private:
417 size_t _used, _committed, _garbage;
418 public:
419 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
420
421 bool heap_region_do(ShenandoahHeapRegion* r) {
422 _used += r->used();
423 _garbage += r->garbage();
424 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
425 return false;
426 }
427
428 size_t used() { return _used; }
429 size_t committed() { return _committed; }
430 size_t garbage() { return _garbage; }
431 };
432
433 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
434 private:
435 ShenandoahHeap* _heap;
436 const char* _phase;
437 ShenandoahVerifier::VerifyRegions _regions;
438 public:
439 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
440 _heap(ShenandoahHeap::heap()), _regions(regions), _phase(phase) {};
441
442 void print_failure(ShenandoahHeapRegion* r, const char* label) {
443 ResourceMark rm;
444
445 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
446
447 stringStream ss;
448 r->print_on(&ss);
449 msg.append("%s", ss.as_string());
450
451 report_vm_error(__FILE__, __LINE__, msg.buffer());
452 }
453
454 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
455 if (!test) {
456 print_failure(r, msg);
457 }
458 }
459
460 bool heap_region_do(ShenandoahHeapRegion* r) {
461 switch (_regions) {
462 case ShenandoahVerifier::_verify_regions_disable:
463 break;
464 case ShenandoahVerifier::_verify_regions_notrash:
465 verify(r, !r->is_trash(),
466 "Should not have trash regions");
467 break;
468 case ShenandoahVerifier::_verify_regions_nocset:
469 verify(r, !r->is_cset(),
470 "Should not have cset regions");
471 break;
472 case ShenandoahVerifier::_verify_regions_notrash_nocset:
473 verify(r, !r->is_trash(),
474 "Should not have trash regions");
475 verify(r, !r->is_cset(),
476 "Should not have cset regions");
477 break;
478 default:
479 ShouldNotReachHere();
480 }
481
482 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
483 "Capacity should match region size");
484
485 verify(r, r->bottom() <= _heap->top_at_mark_start(r->bottom()),
486 "Region top should not be less than bottom");
487
488 verify(r, _heap->top_at_mark_start(r->bottom()) <= r->top(),
489 "TAMS should not be larger than top");
490
491 verify(r, r->get_live_data_bytes() <= r->capacity(),
492 "Live data cannot be larger than capacity");
493
494 verify(r, r->garbage() <= r->capacity(),
495 "Garbage cannot be larger than capacity");
496
497 verify(r, r->used() <= r->capacity(),
498 "Used cannot be larger than capacity");
499
500 verify(r, r->get_shared_allocs() <= r->capacity(),
501 "Shared alloc count should not be larger than capacity");
502
503 verify(r, r->get_tlab_allocs() <= r->capacity(),
504 "TLAB alloc count should not be larger than capacity");
505
506 verify(r, r->get_gclab_allocs() <= r->capacity(),
507 "GCLAB alloc count should not be larger than capacity");
508
509 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
510 "Accurate accounting: shared + TLAB + GCLAB = used");
511
512 verify(r, !r->is_empty() || !r->has_live(),
513 "Empty regions should not have live data");
514
515 verify(r, r->is_cset() == r->in_collection_set(),
516 "Transitional: region flags and collection set agree");
517
518 verify(r, r->is_empty() || r->first_alloc_seq_num() != 0,
519 "Non-empty regions should have first timestamp set");
520
521 verify(r, r->is_empty() || r->last_alloc_seq_num() != 0,
522 "Non-empty regions should have last timestamp set");
523
524 verify(r, r->first_alloc_seq_num() <= r->last_alloc_seq_num(),
525 "First timestamp should not be greater than last timestamp");
526
527 return false;
528 }
529 };
530
531 class ShenandoahVerifierReachableTask : public AbstractGangTask {
532 private:
533 const char* _label;
534 ShenandoahRootProcessor* _rp;
535 ShenandoahVerifier::VerifyOptions _options;
536 ShenandoahHeap* _heap;
537 ShenandoahLivenessData* _ld;
538 MarkBitMap* _bitmap;
539 volatile size_t _processed;
540
541 public:
542 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
543 ShenandoahLivenessData* ld,
544 ShenandoahRootProcessor* rp,
545 const char* label,
546 ShenandoahVerifier::VerifyOptions options) :
547 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
548 _heap(ShenandoahHeap::heap()), _rp(rp), _ld(ld), _bitmap(bitmap), _processed(0),
549 _label(label), _options(options) {};
550
551 size_t processed() {
552 return _processed;
553 }
554
555 virtual void work(uint worker_id) {
556 ResourceMark rm;
557 ShenandoahVerifierStack stack;
558
559 // On level 2, we need to only check the roots once.
560 // On level 3, we want to check the roots, and seed the local stack.
561 // It is a lesser evil to accept multiple root scans at level 3, because
562 // extended parallelism would buy us out.
563 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
564 || (ShenandoahVerifyLevel >= 3)) {
565 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
566 ShenandoahMessageBuffer("%s, Roots", _label),
567 _options);
568 _rp->process_all_roots_slow(&cl);
569 }
570
571 size_t processed = 0;
572
573 if (ShenandoahVerifyLevel >= 3) {
574 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
575 ShenandoahMessageBuffer("%s, Reachable", _label),
576 _options);
577 while (!stack.is_empty()) {
578 processed++;
579 ShenandoahVerifierTask task = stack.pop();
580 cl.verify_oops_from(task.obj());
581 }
582 }
583
584 Atomic::add(processed, &_processed);
585 }
586 };
587
588 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
589 private:
590 const char* _label;
591 ShenandoahVerifier::VerifyOptions _options;
592 ShenandoahHeap *_heap;
593 ShenandoahHeapRegionSet* _regions;
594 MarkBitMap* _bitmap;
595 ShenandoahLivenessData* _ld;
596 volatile size_t _claimed;
597 volatile size_t _processed;
598
599 public:
600 ShenandoahVerifierMarkedRegionTask(ShenandoahHeapRegionSet* regions, MarkBitMap* bitmap,
601 ShenandoahLivenessData* ld,
602 const char* label,
603 ShenandoahVerifier::VerifyOptions options) :
604 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
605 _heap(ShenandoahHeap::heap()), _regions(regions), _ld(ld), _bitmap(bitmap), _claimed(0), _processed(0),
606 _label(label), _options(options) {};
607
608 size_t processed() {
609 return _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::add(1u, &_claimed) - 1;
620 if (v < _heap->num_regions()) {
621 ShenandoahHeapRegion* r = _regions->get(v);
622 if (!r->is_humongous() && !r->is_trash()) {
623 work_regular(r, stack, cl);
624 } else if (r->is_humongous_start()) {
625 work_humongous(r, stack, cl);
626 }
627 } else {
628 break;
629 }
630 }
631 }
632
633 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
634 size_t processed = 0;
635 HeapWord* obj = r->bottom() + BrooksPointer::word_size();
636 if (_heap->is_marked((oop)obj)) {
637 verify_and_follow(obj, stack, cl, &processed);
638 }
639 Atomic::add(processed, &_processed);
640 }
641
642 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
643 size_t processed = 0;
644 MarkBitMap* mark_bit_map = _heap->mark_bit_map();
645 HeapWord* tams = _heap->top_at_mark_start(r->bottom());
646
647 // Bitmaps, before TAMS
648 if (tams > r->bottom()) {
649 HeapWord* start = r->bottom() + BrooksPointer::word_size();
650 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
651
652 while (addr < tams) {
653 verify_and_follow(addr, stack, cl, &processed);
654 addr += BrooksPointer::word_size();
655 if (addr < tams) {
656 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
657 }
658 }
659 }
660
661 // Size-based, after TAMS
662 {
663 HeapWord* limit = r->top();
664 HeapWord* addr = tams + BrooksPointer::word_size();
665
666 while (addr < limit) {
667 verify_and_follow(addr, stack, cl, &processed);
668 addr += oop(addr)->size() + BrooksPointer::word_size();
669 }
670 }
671
672 Atomic::add(processed, &_processed);
673 }
674
675 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
676 if (!_bitmap->parMark(addr)) return;
677
678 // Verify the object itself:
679 oop obj = oop(addr);
680 cl.verify_oop_standalone(obj);
681
682 // Verify everything reachable from that object too, hopefully realizing
683 // everything was already marked, and never touching further:
684 cl.verify_oops_from(obj);
685 (*processed)++;
686
687 while (!stack.is_empty()) {
688 ShenandoahVerifierTask task = stack.pop();
689 cl.verify_oops_from(task.obj());
690 (*processed)++;
691 }
692 }
693 };
694
695 void ShenandoahVerifier::verify_at_safepoint(const char *label,
696 VerifyForwarded forwarded, VerifyMarked marked,
697 VerifyMatrix matrix, VerifyCollectionSet cset,
698 VerifyLiveness liveness, VerifyRegions regions) {
699 guarantee(SafepointSynchronize::is_at_safepoint(), "only when nothing else happens");
700 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
701
702 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
703 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
704
705 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
706
707 // Heap size checks
708 {
709 ShenandoahHeapLocker lock(_heap->lock());
710
711 ShenandoahCalculateRegionStatsClosure cl;
712 _heap->heap_region_iterate(&cl);
713 size_t heap_used = _heap->used();
714 guarantee(cl.used() == heap_used,
715 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
716 label, heap_used/K, cl.used()/K);
717
718 size_t heap_committed = _heap->committed();
719 guarantee(cl.committed() == heap_committed,
720 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
721 label, heap_committed/K, cl.committed()/K);
722 }
723
724 // Internal heap region checks
725 if (ShenandoahVerifyLevel >= 1) {
726 ShenandoahVerifyHeapRegionClosure cl(label, regions);
727 _heap->heap_region_iterate(&cl,
728 /* skip_cset = */ false,
729 /* skip_humongous_cont = */ false);
730 }
731
732 OrderAccess::fence();
733 _heap->make_tlabs_parsable(false);
734
735 // Allocate temporary bitmap for storing marking wavefront:
736 MemRegion mr = MemRegion(_verification_bit_map->startWord(), _verification_bit_map->endWord());
737 _verification_bit_map->clear_range_large(mr);
738
739 // Allocate temporary array for storing liveness data
740 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
741 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
742
743 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, matrix, cset, liveness, regions);
744
745 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
746 // This verifies what application can see, since it only cares about reachable objects.
747 size_t count_reachable = 0;
748 if (ShenandoahVerifyLevel >= 2) {
749 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
750 ShenandoahPhaseTimings::_num_phases); // no need for stats
751
752 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
753 _heap->workers()->run_task(&task);
754 count_reachable = task.processed();
755 }
756
757 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
758 // not the application, can see during the region scans. There is no reason to process the objects
759 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
760 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
761 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
762 // version
763
764 size_t count_marked = 0;
765 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked) {
766 ShenandoahVerifierMarkedRegionTask task(_heap->regions(), _verification_bit_map, ld, label, options);
767 _heap->workers()->run_task(&task);
768 count_marked = task.processed();
769 } else {
770 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_disable, "Should be");
771 }
772
773 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
774 // marked objects.
775
776 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked && liveness == _verify_liveness_complete) {
777 ShenandoahHeapRegionSet* set = _heap->regions();
778 for (size_t i = 0; i < _heap->num_regions(); i++) {
779 ShenandoahHeapRegion* r = set->get(i);
780
781 juint verf_live = 0;
782 if (r->is_humongous()) {
783 // For humongous objects, test if start region is marked live, and if so,
784 // all humongous regions in that chain have live data equal to their "used".
785 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
786 if (start_live > 0) {
787 verf_live = (juint)(r->used() / HeapWordSize);
788 }
789 } else {
790 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
791 }
792
793 size_t reg_live = r->get_live_data_words();
794 if (reg_live != verf_live) {
795 ResourceMark rm;
796 stringStream ss;
797 r->print_on(&ss);
798 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
799 label, reg_live, verf_live, ss.as_string());
800 }
801 }
802 }
803
804 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
805 label, ShenandoahVerifyLevel, count_reachable, count_marked);
806
807 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
808 }
809
810 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
811 verify_at_safepoint(
812 "Generic Verification",
813 _verify_forwarded_allow, // conservatively allow forwarded
814 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
815 _verify_matrix_disable, // matrix can be inconsistent here
816 _verify_cset_disable, // cset may be inconsistent
817 _verify_liveness_disable, // no reliable liveness data
818 _verify_regions_disable // no reliable region data
819 );
820 }
821
822 void ShenandoahVerifier::verify_before_concmark() {
823 if (_heap->need_update_refs()) {
824 verify_at_safepoint(
825 "Before Mark",
826 _verify_forwarded_allow, // may have forwarded references
827 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
828 _verify_matrix_disable, // matrix is foobared
829 _verify_cset_forwarded, // allow forwarded references to cset
830 _verify_liveness_disable, // no reliable liveness data
831 _verify_regions_notrash // no trash regions
832 );
833 } else {
834 verify_at_safepoint(
835 "Before Mark",
836 _verify_forwarded_none, // UR should have fixed up
837 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
838 _verify_matrix_conservative, // UR should have fixed matrix
839 _verify_cset_none, // UR should have fixed this
840 _verify_liveness_disable, // no reliable liveness data
841 _verify_regions_notrash // no trash regions
842 );
843 }
844 }
845
846 void ShenandoahVerifier::verify_after_concmark() {
847 verify_at_safepoint(
848 "After Mark",
849 _verify_forwarded_none, // no forwarded references
850 _verify_marked, // bitmaps as precise as we can get
851 _verify_matrix_disable, // matrix might be foobared
852 _verify_cset_none, // no references to cset anymore
853 _verify_liveness_complete, // liveness data must be complete here
854 _verify_regions_disable // trash regions not yet recycled
855 );
856 }
857
858 void ShenandoahVerifier::verify_before_evacuation() {
859 // Evacuation is always preceded by mark, but we want to have a sanity check after
860 // selecting the collection set, and (immediate) regions recycling
861 verify_at_safepoint(
862 "Before Evacuation",
863 _verify_forwarded_none, // no forwarded references
864 _verify_marked, // walk over marked objects too
865 _verify_matrix_disable, // skip, verified after mark
866 _verify_cset_disable, // skip, verified after mark
867 _verify_liveness_disable, // skip, verified after mark
868 _verify_regions_disable // trash regions not yet recycled
869 );
870 }
871
872 void ShenandoahVerifier::verify_after_evacuation() {
873 verify_at_safepoint(
874 "After Evacuation",
875 _verify_forwarded_allow, // objects are still forwarded
876 _verify_marked, // bitmaps might be stale, but alloc-after-mark should be well
877 _verify_matrix_disable, // matrix is inconsistent here
878 _verify_cset_forwarded, // all cset refs are fully forwarded
879 _verify_liveness_disable, // no reliable liveness data anymore
880 _verify_regions_notrash // trash regions have been recycled already
881 );
882 }
883
884 void ShenandoahVerifier::verify_before_updaterefs() {
885 verify_at_safepoint(
886 "Before Updating References",
887 _verify_forwarded_allow, // forwarded references allowed
888 _verify_marked, // bitmaps might be stale, but alloc-after-mark should be well
889 _verify_matrix_disable, // matrix is inconsistent here
890 _verify_cset_forwarded, // all cset refs are fully forwarded
891 _verify_liveness_disable, // no reliable liveness data anymore
892 _verify_regions_notrash // trash regions have been recycled already
893 );
894 }
895
896 void ShenandoahVerifier::verify_after_updaterefs() {
897 verify_at_safepoint(
898 "After Updating References",
899 _verify_forwarded_none, // no forwarded references
900 _verify_marked, // bitmaps might be stale, but alloc-after-mark should be well
901 _verify_matrix_conservative, // matrix is conservatively consistent
902 _verify_cset_none, // no cset references, all updated
903 _verify_liveness_disable, // no reliable liveness data anymore
904 _verify_regions_nocset // no cset regions, trash regions have appeared
905 );
906 }
907
908 void ShenandoahVerifier::verify_before_partial() {
909 verify_at_safepoint(
910 "Before Partial GC",
911 _verify_forwarded_none, // cannot have forwarded objects
912 _verify_marked, // bitmaps might be stale, but alloc-after-mark should be well
913 _verify_matrix_conservative, // matrix is conservatively consistent
914 _verify_cset_none, // no cset references before partial
915 _verify_liveness_disable, // no reliable liveness data anymore
916 _verify_regions_notrash_nocset // no trash and no cset regions
917 );
918 }
919
920 void ShenandoahVerifier::verify_after_partial() {
921 verify_at_safepoint(
922 "After Partial GC",
923 _verify_forwarded_none, // cannot have forwarded objects
924 _verify_marked, // bitmaps might be stale, but alloc-after-mark should be well
925 _verify_matrix_conservative, // matrix is conservatively consistent
926 _verify_cset_none, // no cset references left after partial
927 _verify_liveness_disable, // no reliable liveness data anymore
928 _verify_regions_nocset // no cset regions, trash regions allowed
929 );
930 }
931
932 void ShenandoahVerifier::verify_before_fullgc() {
933 verify_at_safepoint(
934 "Before Full GC",
935 _verify_forwarded_allow, // can have forwarded objects
936 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
937 _verify_matrix_disable, // matrix might be foobared
938 _verify_cset_disable, // cset might be foobared
939 _verify_liveness_disable, // no reliable liveness data anymore
940 _verify_regions_disable // no reliable region data here
941 );
942 }
943
944 void ShenandoahVerifier::verify_after_fullgc() {
945 verify_at_safepoint(
946 "After Full GC",
947 _verify_forwarded_none, // all objects are non-forwarded
948 _verify_marked, // all objects are marked
949 _verify_matrix_conservative, // matrix is conservatively consistent
950 _verify_cset_none, // no cset references
951 _verify_liveness_disable, // no reliable liveness data anymore
952 _verify_regions_notrash_nocset // no trash, no cset
953 );
954 }
955
956 void ShenandoahVerifier::verify_oop_fwdptr(oop obj, oop fwd) {
957 guarantee(UseShenandoahGC, "must only be called when Shenandoah is used");
958
959 ShenandoahHeap* heap = ShenandoahHeap::heap();
960
961 guarantee(obj != NULL, "oop is not NULL");
962 guarantee(heap->is_in(obj), "oop must point to a heap address: " PTR_FORMAT, p2i(obj));
963
964 guarantee(fwd != NULL, "forwardee is not NULL");
965 if (!heap->is_in(fwd)) {
966 ResourceMark rm;
967 ShenandoahHeapRegion* r = heap->heap_region_containing(obj);
968 stringStream obj_region;
969 r->print_on(&obj_region);
970
971 fatal("forwardee must point to a heap address: " PTR_FORMAT " -> " PTR_FORMAT "\n %s",
972 p2i(obj), p2i(fwd), obj_region.as_string());
973 }
974
975 if (!oopDesc::unsafe_equals(fwd, obj) &&
976 (heap->heap_region_containing(fwd) ==
977 heap->heap_region_containing(obj))) {
978 ResourceMark rm;
979 ShenandoahHeapRegion* ro = heap->heap_region_containing(obj);
980 stringStream obj_region;
981 ro->print_on(&obj_region);
982
983 ShenandoahHeapRegion* rf = heap->heap_region_containing(fwd);
984 stringStream fwd_region;
985 rf->print_on(&fwd_region);
986
987 fatal("forwardee should be self, or another region: " PTR_FORMAT " -> " PTR_FORMAT "\n %s %s",
988 p2i(obj), p2i(fwd),
989 obj_region.as_string(), fwd_region.as_string());
990 }
991
992 if (!oopDesc::unsafe_equals(obj, fwd)) {
993 oop fwd2 = oop(BrooksPointer::get_raw(fwd));
994 if (!oopDesc::unsafe_equals(fwd, fwd2)) {
995 // We should never be forwarded more than once.
996 ResourceMark rm;
997
998 ShenandoahHeapRegion* ro = heap->heap_region_containing(obj);
999 stringStream obj_region;
1000 ro->print_on(&obj_region);
1001
1002 ShenandoahHeapRegion* rf = heap->heap_region_containing(fwd);
1003 stringStream fwd_region;
1004 rf->print_on(&fwd_region);
1005
1006 ShenandoahHeapRegion* rf2 = heap->heap_region_containing(fwd2);
1007 stringStream fwd2_region;
1008 rf2->print_on(&fwd2_region);
1009
1010 fatal("Multiple forwardings: " PTR_FORMAT " -> " PTR_FORMAT " -> " PTR_FORMAT "\n %s %s %s",
1011 p2i(obj), p2i(fwd), p2i(fwd2),
1012 obj_region.as_string(), fwd_region.as_string(), fwd2_region.as_string());
1013 }
1014 }
1015 }
1016
1017 void ShenandoahVerifier::verify_oop(oop obj) {
1018 oop fwd = oop(BrooksPointer::get_raw(obj));
1019 verify_oop_fwdptr(obj, fwd);
1020 }