1 /* 2 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved. 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 24 #include "precompiled.hpp" 25 26 #include "gc/shenandoah/shenandoahAsserts.hpp" 27 #include "gc/shenandoah/shenandoahForwarding.inline.hpp" 28 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 29 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 30 #include "gc/shenandoah/shenandoahRootProcessor.hpp" 31 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp" 32 #include "gc/shenandoah/shenandoahUtils.hpp" 33 #include "gc/shenandoah/shenandoahVerifier.hpp" 34 #include "memory/allocation.hpp" 35 #include "memory/iterator.inline.hpp" 36 #include "memory/resourceArea.hpp" 37 #include "oops/compressedOops.inline.hpp" 38 #include "runtime/atomic.hpp" 39 #include "utilities/align.hpp" 40 41 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp) 42 #ifdef verify_oop 43 #undef verify_oop 44 #endif 45 46 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure { 47 private: 48 const char* _phase; 49 ShenandoahVerifier::VerifyOptions _options; 50 ShenandoahVerifierStack* _stack; 51 ShenandoahHeap* _heap; 52 MarkBitMap* _map; 53 ShenandoahLivenessData* _ld; 54 void* _interior_loc; 55 oop _loc; 56 57 public: 58 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld, 59 const char* phase, ShenandoahVerifier::VerifyOptions options) : 60 _phase(phase), 61 _options(options), 62 _stack(stack), 63 _heap(ShenandoahHeap::heap()), 64 _map(map), 65 _ld(ld), 66 _interior_loc(NULL), 67 _loc(NULL) { } 68 69 private: 70 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) { 71 if (!test) { 72 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__); 73 } 74 } 75 76 template <class T> 77 void do_oop_work(T* p) { 78 T o = RawAccess<>::oop_load(p); 79 if (!CompressedOops::is_null(o)) { 80 oop obj = CompressedOops::decode_not_null(o); 81 82 // Single threaded verification can use faster non-atomic stack and bitmap 83 // methods. 84 // 85 // For performance reasons, only fully verify non-marked field values. 86 // We are here when the host object for *p is already marked. 87 88 HeapWord* addr = (HeapWord*) obj; 89 if (_map->par_mark(addr)) { 90 verify_oop_at(p, obj); 91 _stack->push(ShenandoahVerifierTask(obj)); 92 } 93 } 94 } 95 96 void verify_oop(oop obj) { 97 // Perform consistency checks with gradually decreasing safety level. This guarantees 98 // that failure report would not try to touch something that was not yet verified to be 99 // safe to process. 100 101 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj), 102 "oop must be in heap"); 103 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj), 104 "oop must be aligned"); 105 106 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj); 107 Klass* obj_klass = obj->klass_or_null(); 108 109 // Verify that obj is not in dead space: 110 { 111 // Do this before touching obj->size() 112 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL, 113 "Object klass pointer should not be NULL"); 114 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass), 115 "Object klass pointer must go to metaspace"); 116 117 HeapWord *obj_addr = (HeapWord *) obj; 118 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(), 119 "Object start should be within the region"); 120 121 if (!obj_reg->is_humongous()) { 122 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(), 123 "Object end should be within the region"); 124 } else { 125 size_t humongous_start = obj_reg->region_number(); 126 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift()); 127 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) { 128 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(), 129 "Humongous object is in continuation that fits it"); 130 } 131 } 132 133 // ------------ obj is safe at this point -------------- 134 135 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(), 136 "Object should be in active region"); 137 138 switch (_options._verify_liveness) { 139 case ShenandoahVerifier::_verify_liveness_disable: 140 // skip 141 break; 142 case ShenandoahVerifier::_verify_liveness_complete: 143 Atomic::add(&_ld[obj_reg->region_number()], (uint) obj->size()); 144 // fallthrough for fast failure for un-live regions: 145 case ShenandoahVerifier::_verify_liveness_conservative: 146 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(), 147 "Object must belong to region with live data"); 148 break; 149 default: 150 assert(false, "Unhandled liveness verification"); 151 } 152 } 153 154 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 155 156 ShenandoahHeapRegion* fwd_reg = NULL; 157 158 if (obj != fwd) { 159 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd), 160 "Forwardee must be in heap"); 161 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd), 162 "Forwardee is set"); 163 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd), 164 "Forwardee must be aligned"); 165 166 // Do this before touching fwd->size() 167 Klass* fwd_klass = fwd->klass_or_null(); 168 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL, 169 "Forwardee klass pointer should not be NULL"); 170 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass), 171 "Forwardee klass pointer must go to metaspace"); 172 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass, 173 "Forwardee klass pointer must go to metaspace"); 174 175 fwd_reg = _heap->heap_region_containing(fwd); 176 177 // Verify that forwardee is not in the dead space: 178 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(), 179 "Should have no humongous forwardees"); 180 181 HeapWord *fwd_addr = (HeapWord *) fwd; 182 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(), 183 "Forwardee start should be within the region"); 184 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(), 185 "Forwardee end should be within the region"); 186 187 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd); 188 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2), 189 "Double forwarding"); 190 } else { 191 fwd_reg = obj_reg; 192 } 193 194 // ------------ obj and fwd are safe at this point -------------- 195 196 switch (_options._verify_marked) { 197 case ShenandoahVerifier::_verify_marked_disable: 198 // skip 199 break; 200 case ShenandoahVerifier::_verify_marked_incomplete: 201 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj), 202 "Must be marked in incomplete bitmap"); 203 break; 204 case ShenandoahVerifier::_verify_marked_complete: 205 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj), 206 "Must be marked in complete bitmap"); 207 break; 208 default: 209 assert(false, "Unhandled mark verification"); 210 } 211 212 switch (_options._verify_forwarded) { 213 case ShenandoahVerifier::_verify_forwarded_disable: 214 // skip 215 break; 216 case ShenandoahVerifier::_verify_forwarded_none: { 217 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd), 218 "Should not be forwarded"); 219 break; 220 } 221 case ShenandoahVerifier::_verify_forwarded_allow: { 222 if (obj != fwd) { 223 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg, 224 "Forwardee should be in another region"); 225 } 226 break; 227 } 228 default: 229 assert(false, "Unhandled forwarding verification"); 230 } 231 232 switch (_options._verify_cset) { 233 case ShenandoahVerifier::_verify_cset_disable: 234 // skip 235 break; 236 case ShenandoahVerifier::_verify_cset_none: 237 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj), 238 "Should not have references to collection set"); 239 break; 240 case ShenandoahVerifier::_verify_cset_forwarded: 241 if (_heap->in_collection_set(obj)) { 242 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd), 243 "Object in collection set, should have forwardee"); 244 } 245 break; 246 default: 247 assert(false, "Unhandled cset verification"); 248 } 249 250 } 251 252 public: 253 /** 254 * Verify object with known interior reference. 255 * @param p interior reference where the object is referenced from; can be off-heap 256 * @param obj verified object 257 */ 258 template <class T> 259 void verify_oop_at(T* p, oop obj) { 260 _interior_loc = p; 261 verify_oop(obj); 262 _interior_loc = NULL; 263 } 264 265 /** 266 * Verify object without known interior reference. 267 * Useful when picking up the object at known offset in heap, 268 * but without knowing what objects reference it. 269 * @param obj verified object 270 */ 271 void verify_oop_standalone(oop obj) { 272 _interior_loc = NULL; 273 verify_oop(obj); 274 _interior_loc = NULL; 275 } 276 277 /** 278 * Verify oop fields from this object. 279 * @param obj host object for verified fields 280 */ 281 void verify_oops_from(oop obj) { 282 _loc = obj; 283 obj->oop_iterate(this); 284 _loc = NULL; 285 } 286 287 virtual void do_oop(oop* p) { do_oop_work(p); } 288 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 289 }; 290 291 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure { 292 private: 293 size_t _used, _committed, _garbage; 294 public: 295 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {}; 296 297 void heap_region_do(ShenandoahHeapRegion* r) { 298 _used += r->used(); 299 _garbage += r->garbage(); 300 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0; 301 } 302 303 size_t used() { return _used; } 304 size_t committed() { return _committed; } 305 size_t garbage() { return _garbage; } 306 }; 307 308 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure { 309 private: 310 ShenandoahHeap* _heap; 311 const char* _phase; 312 ShenandoahVerifier::VerifyRegions _regions; 313 public: 314 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) : 315 _heap(ShenandoahHeap::heap()), 316 _phase(phase), 317 _regions(regions) {}; 318 319 void print_failure(ShenandoahHeapRegion* r, const char* label) { 320 ResourceMark rm; 321 322 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label); 323 324 stringStream ss; 325 r->print_on(&ss); 326 msg.append("%s", ss.as_string()); 327 328 report_vm_error(__FILE__, __LINE__, msg.buffer()); 329 } 330 331 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) { 332 if (!test) { 333 print_failure(r, msg); 334 } 335 } 336 337 void heap_region_do(ShenandoahHeapRegion* r) { 338 switch (_regions) { 339 case ShenandoahVerifier::_verify_regions_disable: 340 break; 341 case ShenandoahVerifier::_verify_regions_notrash: 342 verify(r, !r->is_trash(), 343 "Should not have trash regions"); 344 break; 345 case ShenandoahVerifier::_verify_regions_nocset: 346 verify(r, !r->is_cset(), 347 "Should not have cset regions"); 348 break; 349 case ShenandoahVerifier::_verify_regions_notrash_nocset: 350 verify(r, !r->is_trash(), 351 "Should not have trash regions"); 352 verify(r, !r->is_cset(), 353 "Should not have cset regions"); 354 break; 355 default: 356 ShouldNotReachHere(); 357 } 358 359 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(), 360 "Capacity should match region size"); 361 362 verify(r, r->bottom() <= r->top(), 363 "Region top should not be less than bottom"); 364 365 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r), 366 "Region TAMS should not be less than bottom"); 367 368 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(), 369 "Complete TAMS should not be larger than top"); 370 371 verify(r, r->get_live_data_bytes() <= r->capacity(), 372 "Live data cannot be larger than capacity"); 373 374 verify(r, r->garbage() <= r->capacity(), 375 "Garbage cannot be larger than capacity"); 376 377 verify(r, r->used() <= r->capacity(), 378 "Used cannot be larger than capacity"); 379 380 verify(r, r->get_shared_allocs() <= r->capacity(), 381 "Shared alloc count should not be larger than capacity"); 382 383 verify(r, r->get_tlab_allocs() <= r->capacity(), 384 "TLAB alloc count should not be larger than capacity"); 385 386 verify(r, r->get_gclab_allocs() <= r->capacity(), 387 "GCLAB alloc count should not be larger than capacity"); 388 389 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(), 390 "Accurate accounting: shared + TLAB + GCLAB = used"); 391 392 verify(r, !r->is_empty() || !r->has_live(), 393 "Empty regions should not have live data"); 394 395 verify(r, r->is_cset() == _heap->collection_set()->is_in(r), 396 "Transitional: region flags and collection set agree"); 397 398 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0, 399 "Non-empty regions should have first seqnum set"); 400 401 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0), 402 "Non-empty regions should have first seqnum set to either GC or mutator"); 403 404 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0, 405 "Non-empty regions should have last seqnum set"); 406 407 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0), 408 "Non-empty regions should have last seqnum set to either GC or mutator"); 409 410 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(), 411 "First seqnum should not be greater than last timestamp"); 412 413 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(), 414 "First mutator seqnum should not be greater than last seqnum"); 415 416 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(), 417 "First GC seqnum should not be greater than last seqnum"); 418 } 419 }; 420 421 class ShenandoahVerifierReachableTask : public AbstractGangTask { 422 private: 423 const char* _label; 424 ShenandoahRootVerifier* _verifier; 425 ShenandoahVerifier::VerifyOptions _options; 426 ShenandoahHeap* _heap; 427 ShenandoahLivenessData* _ld; 428 MarkBitMap* _bitmap; 429 volatile size_t _processed; 430 431 public: 432 ShenandoahVerifierReachableTask(MarkBitMap* bitmap, 433 ShenandoahLivenessData* ld, 434 ShenandoahRootVerifier* verifier, 435 const char* label, 436 ShenandoahVerifier::VerifyOptions options) : 437 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"), 438 _label(label), 439 _verifier(verifier), 440 _options(options), 441 _heap(ShenandoahHeap::heap()), 442 _ld(ld), 443 _bitmap(bitmap), 444 _processed(0) {}; 445 446 size_t processed() { 447 return _processed; 448 } 449 450 virtual void work(uint worker_id) { 451 ResourceMark rm; 452 ShenandoahVerifierStack stack; 453 454 // On level 2, we need to only check the roots once. 455 // On level 3, we want to check the roots, and seed the local stack. 456 // It is a lesser evil to accept multiple root scans at level 3, because 457 // extended parallelism would buy us out. 458 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0)) 459 || (ShenandoahVerifyLevel >= 3)) { 460 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld, 461 ShenandoahMessageBuffer("%s, Roots", _label), 462 _options); 463 if (_heap->unload_classes()) { 464 _verifier->strong_roots_do(&cl); 465 } else { 466 _verifier->roots_do(&cl); 467 } 468 } 469 470 size_t processed = 0; 471 472 if (ShenandoahVerifyLevel >= 3) { 473 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld, 474 ShenandoahMessageBuffer("%s, Reachable", _label), 475 _options); 476 while (!stack.is_empty()) { 477 processed++; 478 ShenandoahVerifierTask task = stack.pop(); 479 cl.verify_oops_from(task.obj()); 480 } 481 } 482 483 Atomic::add(&_processed, processed); 484 } 485 }; 486 487 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask { 488 private: 489 const char* _label; 490 ShenandoahVerifier::VerifyOptions _options; 491 ShenandoahHeap *_heap; 492 MarkBitMap* _bitmap; 493 ShenandoahLivenessData* _ld; 494 volatile size_t _claimed; 495 volatile size_t _processed; 496 497 public: 498 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap, 499 ShenandoahLivenessData* ld, 500 const char* label, 501 ShenandoahVerifier::VerifyOptions options) : 502 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"), 503 _label(label), 504 _options(options), 505 _heap(ShenandoahHeap::heap()), 506 _bitmap(bitmap), 507 _ld(ld), 508 _claimed(0), 509 _processed(0) {}; 510 511 size_t processed() { 512 return _processed; 513 } 514 515 virtual void work(uint worker_id) { 516 ShenandoahVerifierStack stack; 517 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld, 518 ShenandoahMessageBuffer("%s, Marked", _label), 519 _options); 520 521 while (true) { 522 size_t v = Atomic::add(&_claimed, 1u) - 1; 523 if (v < _heap->num_regions()) { 524 ShenandoahHeapRegion* r = _heap->get_region(v); 525 if (!r->is_humongous() && !r->is_trash()) { 526 work_regular(r, stack, cl); 527 } else if (r->is_humongous_start()) { 528 work_humongous(r, stack, cl); 529 } 530 } else { 531 break; 532 } 533 } 534 } 535 536 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) { 537 size_t processed = 0; 538 HeapWord* obj = r->bottom(); 539 if (_heap->complete_marking_context()->is_marked((oop)obj)) { 540 verify_and_follow(obj, stack, cl, &processed); 541 } 542 Atomic::add(&_processed, processed); 543 } 544 545 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) { 546 size_t processed = 0; 547 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map(); 548 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r); 549 550 // Bitmaps, before TAMS 551 if (tams > r->bottom()) { 552 HeapWord* start = r->bottom(); 553 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams); 554 555 while (addr < tams) { 556 verify_and_follow(addr, stack, cl, &processed); 557 addr += 1; 558 if (addr < tams) { 559 addr = mark_bit_map->get_next_marked_addr(addr, tams); 560 } 561 } 562 } 563 564 // Size-based, after TAMS 565 { 566 HeapWord* limit = r->top(); 567 HeapWord* addr = tams; 568 569 while (addr < limit) { 570 verify_and_follow(addr, stack, cl, &processed); 571 addr += oop(addr)->size(); 572 } 573 } 574 575 Atomic::add(&_processed, processed); 576 } 577 578 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) { 579 if (!_bitmap->par_mark(addr)) return; 580 581 // Verify the object itself: 582 oop obj = oop(addr); 583 cl.verify_oop_standalone(obj); 584 585 // Verify everything reachable from that object too, hopefully realizing 586 // everything was already marked, and never touching further: 587 cl.verify_oops_from(obj); 588 (*processed)++; 589 590 while (!stack.is_empty()) { 591 ShenandoahVerifierTask task = stack.pop(); 592 cl.verify_oops_from(task.obj()); 593 (*processed)++; 594 } 595 } 596 }; 597 598 class VerifyThreadGCState : public ThreadClosure { 599 private: 600 const char* _label; 601 char _expected; 602 603 public: 604 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {} 605 void do_thread(Thread* t) { 606 char actual = ShenandoahThreadLocalData::gc_state(t); 607 if (actual != _expected) { 608 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual); 609 } 610 } 611 }; 612 613 class ShenandoahGCStateResetter : public StackObj { 614 private: 615 ShenandoahHeap* const _heap; 616 char _gc_state; 617 618 public: 619 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) { 620 _gc_state = _heap->gc_state(); 621 _heap->_gc_state.clear(); 622 } 623 624 ~ShenandoahGCStateResetter() { 625 _heap->_gc_state.set(_gc_state); 626 assert(_heap->gc_state() == _gc_state, "Should be restored"); 627 } 628 }; 629 630 void ShenandoahVerifier::verify_at_safepoint(const char *label, 631 VerifyForwarded forwarded, VerifyMarked marked, 632 VerifyCollectionSet cset, 633 VerifyLiveness liveness, VerifyRegions regions, 634 VerifyGCState gcstate) { 635 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens"); 636 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize"); 637 638 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check 639 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/); 640 641 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel); 642 643 // GC state checks 644 { 645 char expected = -1; 646 bool enabled; 647 switch (gcstate) { 648 case _verify_gcstate_disable: 649 enabled = false; 650 break; 651 case _verify_gcstate_forwarded: 652 enabled = true; 653 expected = ShenandoahHeap::HAS_FORWARDED; 654 break; 655 case _verify_gcstate_evacuation: 656 enabled = true; 657 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION; 658 break; 659 case _verify_gcstate_stable: 660 enabled = true; 661 expected = ShenandoahHeap::STABLE; 662 break; 663 default: 664 enabled = false; 665 assert(false, "Unhandled gc-state verification"); 666 } 667 668 if (enabled) { 669 char actual = _heap->gc_state(); 670 if (actual != expected) { 671 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual); 672 } 673 674 VerifyThreadGCState vtgcs(label, expected); 675 Threads::java_threads_do(&vtgcs); 676 } 677 } 678 679 // Deactivate barriers temporarily: Verifier wants plain heap accesses 680 ShenandoahGCStateResetter resetter; 681 682 // Heap size checks 683 { 684 ShenandoahHeapLocker lock(_heap->lock()); 685 686 ShenandoahCalculateRegionStatsClosure cl; 687 _heap->heap_region_iterate(&cl); 688 size_t heap_used = _heap->used(); 689 guarantee(cl.used() == heap_used, 690 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s", 691 label, 692 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used), 693 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used())); 694 695 size_t heap_committed = _heap->committed(); 696 guarantee(cl.committed() == heap_committed, 697 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s", 698 label, 699 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed), 700 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed())); 701 } 702 703 // Internal heap region checks 704 if (ShenandoahVerifyLevel >= 1) { 705 ShenandoahVerifyHeapRegionClosure cl(label, regions); 706 _heap->heap_region_iterate(&cl); 707 } 708 709 OrderAccess::fence(); 710 _heap->make_parsable(false); 711 712 // Allocate temporary bitmap for storing marking wavefront: 713 _verification_bit_map->clear(); 714 715 // Allocate temporary array for storing liveness data 716 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC); 717 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0); 718 719 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate); 720 721 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap. 722 // This verifies what application can see, since it only cares about reachable objects. 723 size_t count_reachable = 0; 724 if (ShenandoahVerifyLevel >= 2) { 725 ShenandoahRootVerifier verifier; 726 727 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options); 728 _heap->workers()->run_task(&task); 729 count_reachable = task.processed(); 730 } 731 732 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector, 733 // not the application, can see during the region scans. There is no reason to process the objects 734 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS: 735 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics 736 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect) 737 // version 738 739 size_t count_marked = 0; 740 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) { 741 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete"); 742 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options); 743 _heap->workers()->run_task(&task); 744 count_marked = task.processed(); 745 } else { 746 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be"); 747 } 748 749 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes 750 // marked objects. 751 752 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) { 753 for (size_t i = 0; i < _heap->num_regions(); i++) { 754 ShenandoahHeapRegion* r = _heap->get_region(i); 755 756 juint verf_live = 0; 757 if (r->is_humongous()) { 758 // For humongous objects, test if start region is marked live, and if so, 759 // all humongous regions in that chain have live data equal to their "used". 760 juint start_live = Atomic::load_acquire(&ld[r->humongous_start_region()->region_number()]); 761 if (start_live > 0) { 762 verf_live = (juint)(r->used() / HeapWordSize); 763 } 764 } else { 765 verf_live = Atomic::load_acquire(&ld[r->region_number()]); 766 } 767 768 size_t reg_live = r->get_live_data_words(); 769 if (reg_live != verf_live) { 770 ResourceMark rm; 771 stringStream ss; 772 r->print_on(&ss); 773 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s", 774 label, reg_live, verf_live, ss.as_string()); 775 } 776 } 777 } 778 779 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)", 780 label, ShenandoahVerifyLevel, count_reachable, count_marked); 781 782 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld); 783 } 784 785 void ShenandoahVerifier::verify_generic(VerifyOption vo) { 786 verify_at_safepoint( 787 "Generic Verification", 788 _verify_forwarded_allow, // conservatively allow forwarded 789 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 790 _verify_cset_disable, // cset may be inconsistent 791 _verify_liveness_disable, // no reliable liveness data 792 _verify_regions_disable, // no reliable region data 793 _verify_gcstate_disable // no data about gcstate 794 ); 795 } 796 797 void ShenandoahVerifier::verify_before_concmark() { 798 if (_heap->has_forwarded_objects()) { 799 verify_at_safepoint( 800 "Before Mark", 801 _verify_forwarded_allow, // may have forwarded references 802 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 803 _verify_cset_forwarded, // allow forwarded references to cset 804 _verify_liveness_disable, // no reliable liveness data 805 _verify_regions_notrash, // no trash regions 806 _verify_gcstate_forwarded // there are forwarded objects 807 ); 808 } else { 809 verify_at_safepoint( 810 "Before Mark", 811 _verify_forwarded_none, // UR should have fixed up 812 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 813 _verify_cset_none, // UR should have fixed this 814 _verify_liveness_disable, // no reliable liveness data 815 _verify_regions_notrash, // no trash regions 816 _verify_gcstate_stable // there are no forwarded objects 817 ); 818 } 819 } 820 821 void ShenandoahVerifier::verify_after_concmark() { 822 verify_at_safepoint( 823 "After Mark", 824 _verify_forwarded_none, // no forwarded references 825 _verify_marked_complete, // bitmaps as precise as we can get 826 _verify_cset_none, // no references to cset anymore 827 _verify_liveness_complete, // liveness data must be complete here 828 _verify_regions_disable, // trash regions not yet recycled 829 _verify_gcstate_stable // mark should have stabilized the heap 830 ); 831 } 832 833 void ShenandoahVerifier::verify_before_evacuation() { 834 verify_at_safepoint( 835 "Before Evacuation", 836 _verify_forwarded_none, // no forwarded references 837 _verify_marked_complete, // walk over marked objects too 838 _verify_cset_disable, // non-forwarded references to cset expected 839 _verify_liveness_complete, // liveness data must be complete here 840 _verify_regions_disable, // trash regions not yet recycled 841 _verify_gcstate_stable // mark should have stabilized the heap 842 ); 843 } 844 845 void ShenandoahVerifier::verify_during_evacuation() { 846 verify_at_safepoint( 847 "During Evacuation", 848 _verify_forwarded_allow, // some forwarded references are allowed 849 _verify_marked_disable, // walk only roots 850 _verify_cset_disable, // some cset references are not forwarded yet 851 _verify_liveness_disable, // liveness data might be already stale after pre-evacs 852 _verify_regions_disable, // trash regions not yet recycled 853 _verify_gcstate_evacuation // evacuation is in progress 854 ); 855 } 856 857 void ShenandoahVerifier::verify_after_evacuation() { 858 verify_at_safepoint( 859 "After Evacuation", 860 _verify_forwarded_allow, // objects are still forwarded 861 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 862 _verify_cset_forwarded, // all cset refs are fully forwarded 863 _verify_liveness_disable, // no reliable liveness data anymore 864 _verify_regions_notrash, // trash regions have been recycled already 865 _verify_gcstate_forwarded // evacuation produced some forwarded objects 866 ); 867 } 868 869 void ShenandoahVerifier::verify_before_updaterefs() { 870 verify_at_safepoint( 871 "Before Updating References", 872 _verify_forwarded_allow, // forwarded references allowed 873 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 874 _verify_cset_forwarded, // all cset refs are fully forwarded 875 _verify_liveness_disable, // no reliable liveness data anymore 876 _verify_regions_notrash, // trash regions have been recycled already 877 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects 878 ); 879 } 880 881 void ShenandoahVerifier::verify_after_updaterefs() { 882 verify_at_safepoint( 883 "After Updating References", 884 _verify_forwarded_none, // no forwarded references 885 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 886 _verify_cset_none, // no cset references, all updated 887 _verify_liveness_disable, // no reliable liveness data anymore 888 _verify_regions_nocset, // no cset regions, trash regions have appeared 889 _verify_gcstate_stable // update refs had cleaned up forwarded objects 890 ); 891 } 892 893 void ShenandoahVerifier::verify_after_degenerated() { 894 verify_at_safepoint( 895 "After Degenerated GC", 896 _verify_forwarded_none, // all objects are non-forwarded 897 _verify_marked_complete, // all objects are marked in complete bitmap 898 _verify_cset_none, // no cset references 899 _verify_liveness_disable, // no reliable liveness data anymore 900 _verify_regions_notrash_nocset, // no trash, no cset 901 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects 902 ); 903 } 904 905 void ShenandoahVerifier::verify_before_traversal() { 906 verify_at_safepoint( 907 "Before Traversal", 908 _verify_forwarded_none, // cannot have forwarded objects 909 _verify_marked_disable, // bitmaps are not relevant before traversal 910 _verify_cset_none, // no cset references before traversal 911 _verify_liveness_disable, // no reliable liveness data anymore 912 _verify_regions_notrash_nocset, // no trash and no cset regions 913 _verify_gcstate_stable // nothing forwarded before traversal 914 ); 915 } 916 917 void ShenandoahVerifier::verify_after_traversal() { 918 verify_at_safepoint( 919 "After Traversal", 920 _verify_forwarded_none, // cannot have forwarded objects 921 _verify_marked_complete, // should have complete marking after traversal 922 _verify_cset_none, // no cset references left after traversal 923 _verify_liveness_disable, // liveness data is not collected for new allocations 924 _verify_regions_nocset, // no cset regions, trash regions allowed 925 _verify_gcstate_stable // nothing forwarded after traversal 926 ); 927 } 928 929 void ShenandoahVerifier::verify_before_fullgc() { 930 verify_at_safepoint( 931 "Before Full GC", 932 _verify_forwarded_allow, // can have forwarded objects 933 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 934 _verify_cset_disable, // cset might be foobared 935 _verify_liveness_disable, // no reliable liveness data anymore 936 _verify_regions_disable, // no reliable region data here 937 _verify_gcstate_disable // no reliable gcstate data 938 ); 939 } 940 941 void ShenandoahVerifier::verify_after_fullgc() { 942 verify_at_safepoint( 943 "After Full GC", 944 _verify_forwarded_none, // all objects are non-forwarded 945 _verify_marked_complete, // all objects are marked in complete bitmap 946 _verify_cset_none, // no cset references 947 _verify_liveness_disable, // no reliable liveness data anymore 948 _verify_regions_notrash_nocset, // no trash, no cset 949 _verify_gcstate_stable // full gc cleaned up everything 950 ); 951 } 952 953 class ShenandoahVerifyNoForwared : public OopClosure { 954 private: 955 template <class T> 956 void do_oop_work(T* p) { 957 T o = RawAccess<>::oop_load(p); 958 if (!CompressedOops::is_null(o)) { 959 oop obj = CompressedOops::decode_not_null(o); 960 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 961 if (obj != fwd) { 962 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL, 963 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__); 964 } 965 } 966 } 967 968 public: 969 void do_oop(narrowOop* p) { do_oop_work(p); } 970 void do_oop(oop* p) { do_oop_work(p); } 971 }; 972 973 class ShenandoahVerifyInToSpaceClosure : public OopClosure { 974 private: 975 template <class T> 976 void do_oop_work(T* p) { 977 T o = RawAccess<>::oop_load(p); 978 if (!CompressedOops::is_null(o)) { 979 oop obj = CompressedOops::decode_not_null(o); 980 ShenandoahHeap* heap = ShenandoahHeap::heap_no_check(); 981 982 if (!heap->marking_context()->is_marked(obj)) { 983 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL, 984 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__); 985 } 986 987 if (heap->in_collection_set(obj)) { 988 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL, 989 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__); 990 } 991 992 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 993 if (obj != fwd) { 994 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL, 995 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__); 996 } 997 } 998 } 999 1000 public: 1001 void do_oop(narrowOop* p) { do_oop_work(p); } 1002 void do_oop(oop* p) { do_oop_work(p); } 1003 }; 1004 1005 void ShenandoahVerifier::verify_roots_in_to_space() { 1006 ShenandoahRootVerifier verifier; 1007 ShenandoahVerifyInToSpaceClosure cl; 1008 verifier.oops_do(&cl); 1009 } 1010 1011 void ShenandoahVerifier::verify_roots_no_forwarded() { 1012 ShenandoahRootVerifier verifier; 1013 ShenandoahVerifyNoForwared cl; 1014 verifier.oops_do(&cl); 1015 } 1016 1017 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) { 1018 ShenandoahRootVerifier verifier; 1019 verifier.excludes(types); 1020 ShenandoahVerifyNoForwared cl; 1021 verifier.oops_do(&cl); 1022 }