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