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->par_mark(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(obj->size() + ShenandoahForwarding::word_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 (!oopDesc::equals_raw(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, oopDesc::equals_raw(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, oopDesc::equals_raw(obj, fwd), 215 "Should not be forwarded"); 216 break; 217 } 218 case ShenandoahVerifier::_verify_forwarded_allow: { 219 if (!oopDesc::equals_raw(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, !oopDesc::equals_raw(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 ShenandoahRootProcessor* _rp; 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 ShenandoahRootProcessor* rp, 432 const char* label, 433 ShenandoahVerifier::VerifyOptions options) : 434 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"), 435 _label(label), 436 _rp(rp), 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 _rp->process_all_roots_slow(&cl); 461 } 462 463 size_t processed = 0; 464 465 if (ShenandoahVerifyLevel >= 3) { 466 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld, 467 ShenandoahMessageBuffer("%s, Reachable", _label), 468 _options); 469 while (!stack.is_empty()) { 470 processed++; 471 ShenandoahVerifierTask task = stack.pop(); 472 cl.verify_oops_from(task.obj()); 473 } 474 } 475 476 Atomic::add(processed, &_processed); 477 } 478 }; 479 480 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask { 481 private: 482 const char* _label; 483 ShenandoahVerifier::VerifyOptions _options; 484 ShenandoahHeap *_heap; 485 MarkBitMap* _bitmap; 486 ShenandoahLivenessData* _ld; 487 volatile size_t _claimed; 488 volatile size_t _processed; 489 490 public: 491 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap, 492 ShenandoahLivenessData* ld, 493 const char* label, 494 ShenandoahVerifier::VerifyOptions options) : 495 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"), 496 _label(label), 497 _options(options), 498 _heap(ShenandoahHeap::heap()), 499 _bitmap(bitmap), 500 _ld(ld), 501 _claimed(0), 502 _processed(0) {}; 503 504 size_t processed() { 505 return _processed; 506 } 507 508 virtual void work(uint worker_id) { 509 ShenandoahVerifierStack stack; 510 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld, 511 ShenandoahMessageBuffer("%s, Marked", _label), 512 _options); 513 514 while (true) { 515 size_t v = Atomic::add(1u, &_claimed) - 1; 516 if (v < _heap->num_regions()) { 517 ShenandoahHeapRegion* r = _heap->get_region(v); 518 if (!r->is_humongous() && !r->is_trash()) { 519 work_regular(r, stack, cl); 520 } else if (r->is_humongous_start()) { 521 work_humongous(r, stack, cl); 522 } 523 } else { 524 break; 525 } 526 } 527 } 528 529 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) { 530 size_t processed = 0; 531 HeapWord* obj = r->bottom() + ShenandoahForwarding::word_size(); 532 if (_heap->complete_marking_context()->is_marked((oop)obj)) { 533 verify_and_follow(obj, stack, cl, &processed); 534 } 535 Atomic::add(processed, &_processed); 536 } 537 538 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) { 539 size_t processed = 0; 540 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map(); 541 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r); 542 543 // Bitmaps, before TAMS 544 if (tams > r->bottom()) { 545 HeapWord* start = r->bottom() + ShenandoahForwarding::word_size(); 546 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams); 547 548 while (addr < tams) { 549 verify_and_follow(addr, stack, cl, &processed); 550 addr += ShenandoahForwarding::word_size(); 551 if (addr < tams) { 552 addr = mark_bit_map->get_next_marked_addr(addr, tams); 553 } 554 } 555 } 556 557 // Size-based, after TAMS 558 { 559 HeapWord* limit = r->top(); 560 HeapWord* addr = tams + ShenandoahForwarding::word_size(); 561 562 while (addr < limit) { 563 verify_and_follow(addr, stack, cl, &processed); 564 addr += oop(addr)->size() + ShenandoahForwarding::word_size(); 565 } 566 } 567 568 Atomic::add(processed, &_processed); 569 } 570 571 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) { 572 if (!_bitmap->par_mark(addr)) return; 573 574 // Verify the object itself: 575 oop obj = oop(addr); 576 cl.verify_oop_standalone(obj); 577 578 // Verify everything reachable from that object too, hopefully realizing 579 // everything was already marked, and never touching further: 580 cl.verify_oops_from(obj); 581 (*processed)++; 582 583 while (!stack.is_empty()) { 584 ShenandoahVerifierTask task = stack.pop(); 585 cl.verify_oops_from(task.obj()); 586 (*processed)++; 587 } 588 } 589 }; 590 591 class VerifyThreadGCState : public ThreadClosure { 592 private: 593 const char* _label; 594 char _expected; 595 596 public: 597 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {} 598 void do_thread(Thread* t) { 599 char actual = ShenandoahThreadLocalData::gc_state(t); 600 if (actual != _expected) { 601 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual); 602 } 603 } 604 }; 605 606 void ShenandoahVerifier::verify_at_safepoint(const char *label, 607 VerifyForwarded forwarded, VerifyMarked marked, 608 VerifyCollectionSet cset, 609 VerifyLiveness liveness, VerifyRegions regions, 610 VerifyGCState gcstate) { 611 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens"); 612 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize"); 613 614 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check 615 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/); 616 617 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel); 618 619 // GC state checks 620 { 621 char expected = -1; 622 bool enabled; 623 switch (gcstate) { 624 case _verify_gcstate_disable: 625 enabled = false; 626 break; 627 case _verify_gcstate_forwarded: 628 enabled = true; 629 expected = ShenandoahHeap::HAS_FORWARDED; 630 break; 631 case _verify_gcstate_evacuation: 632 enabled = true; 633 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION; 634 break; 635 case _verify_gcstate_stable: 636 enabled = true; 637 expected = ShenandoahHeap::STABLE; 638 break; 639 default: 640 enabled = false; 641 assert(false, "Unhandled gc-state verification"); 642 } 643 644 if (enabled) { 645 char actual = _heap->gc_state(); 646 if (actual != expected) { 647 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual); 648 } 649 650 VerifyThreadGCState vtgcs(label, expected); 651 Threads::java_threads_do(&vtgcs); 652 } 653 } 654 655 // Heap size checks 656 { 657 ShenandoahHeapLocker lock(_heap->lock()); 658 659 ShenandoahCalculateRegionStatsClosure cl; 660 _heap->heap_region_iterate(&cl); 661 size_t heap_used = _heap->used(); 662 guarantee(cl.used() == heap_used, 663 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K", 664 label, heap_used/K, cl.used()/K); 665 666 size_t heap_committed = _heap->committed(); 667 guarantee(cl.committed() == heap_committed, 668 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K", 669 label, heap_committed/K, cl.committed()/K); 670 } 671 672 // Internal heap region checks 673 if (ShenandoahVerifyLevel >= 1) { 674 ShenandoahVerifyHeapRegionClosure cl(label, regions); 675 _heap->heap_region_iterate(&cl); 676 } 677 678 OrderAccess::fence(); 679 _heap->make_parsable(false); 680 681 // Allocate temporary bitmap for storing marking wavefront: 682 _verification_bit_map->clear(); 683 684 // Allocate temporary array for storing liveness data 685 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC); 686 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0); 687 688 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate); 689 690 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap. 691 // This verifies what application can see, since it only cares about reachable objects. 692 size_t count_reachable = 0; 693 if (ShenandoahVerifyLevel >= 2) { 694 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(), 695 ShenandoahPhaseTimings::_num_phases); // no need for stats 696 697 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options); 698 _heap->workers()->run_task(&task); 699 count_reachable = task.processed(); 700 } 701 702 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector, 703 // not the application, can see during the region scans. There is no reason to process the objects 704 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS: 705 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics 706 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect) 707 // version 708 709 size_t count_marked = 0; 710 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) { 711 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete"); 712 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options); 713 _heap->workers()->run_task(&task); 714 count_marked = task.processed(); 715 } else { 716 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be"); 717 } 718 719 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes 720 // marked objects. 721 722 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) { 723 for (size_t i = 0; i < _heap->num_regions(); i++) { 724 ShenandoahHeapRegion* r = _heap->get_region(i); 725 726 juint verf_live = 0; 727 if (r->is_humongous()) { 728 // For humongous objects, test if start region is marked live, and if so, 729 // all humongous regions in that chain have live data equal to their "used". 730 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]); 731 if (start_live > 0) { 732 verf_live = (juint)(r->used() / HeapWordSize); 733 } 734 } else { 735 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]); 736 } 737 738 size_t reg_live = r->get_live_data_words(); 739 if (reg_live != verf_live) { 740 ResourceMark rm; 741 stringStream ss; 742 r->print_on(&ss); 743 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s", 744 label, reg_live, verf_live, ss.as_string()); 745 } 746 } 747 } 748 749 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)", 750 label, ShenandoahVerifyLevel, count_reachable, count_marked); 751 752 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld); 753 } 754 755 void ShenandoahVerifier::verify_generic(VerifyOption vo) { 756 verify_at_safepoint( 757 "Generic Verification", 758 _verify_forwarded_allow, // conservatively allow forwarded 759 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 760 _verify_cset_disable, // cset may be inconsistent 761 _verify_liveness_disable, // no reliable liveness data 762 _verify_regions_disable, // no reliable region data 763 _verify_gcstate_disable // no data about gcstate 764 ); 765 } 766 767 void ShenandoahVerifier::verify_before_concmark() { 768 if (_heap->has_forwarded_objects()) { 769 verify_at_safepoint( 770 "Before Mark", 771 _verify_forwarded_allow, // may have forwarded references 772 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 773 _verify_cset_forwarded, // allow forwarded references to cset 774 _verify_liveness_disable, // no reliable liveness data 775 _verify_regions_notrash, // no trash regions 776 _verify_gcstate_forwarded // there are forwarded objects 777 ); 778 } else { 779 verify_at_safepoint( 780 "Before Mark", 781 _verify_forwarded_none, // UR should have fixed up 782 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 783 _verify_cset_none, // UR should have fixed this 784 _verify_liveness_disable, // no reliable liveness data 785 _verify_regions_notrash, // no trash regions 786 _verify_gcstate_stable // there are no forwarded objects 787 ); 788 } 789 } 790 791 void ShenandoahVerifier::verify_after_concmark() { 792 verify_at_safepoint( 793 "After Mark", 794 _verify_forwarded_none, // no forwarded references 795 _verify_marked_complete, // bitmaps as precise as we can get 796 _verify_cset_none, // no references to cset anymore 797 _verify_liveness_complete, // liveness data must be complete here 798 _verify_regions_disable, // trash regions not yet recycled 799 _verify_gcstate_stable // mark should have stabilized the heap 800 ); 801 } 802 803 void ShenandoahVerifier::verify_before_evacuation() { 804 verify_at_safepoint( 805 "Before Evacuation", 806 _verify_forwarded_none, // no forwarded references 807 _verify_marked_complete, // walk over marked objects too 808 _verify_cset_disable, // non-forwarded references to cset expected 809 _verify_liveness_complete, // liveness data must be complete here 810 _verify_regions_disable, // trash regions not yet recycled 811 _verify_gcstate_stable // mark should have stabilized the heap 812 ); 813 } 814 815 void ShenandoahVerifier::verify_during_evacuation() { 816 verify_at_safepoint( 817 "During Evacuation", 818 _verify_forwarded_allow, // some forwarded references are allowed 819 _verify_marked_disable, // walk only roots 820 _verify_cset_disable, // some cset references are not forwarded yet 821 _verify_liveness_disable, // liveness data might be already stale after pre-evacs 822 _verify_regions_disable, // trash regions not yet recycled 823 _verify_gcstate_evacuation // evacuation is in progress 824 ); 825 } 826 827 void ShenandoahVerifier::verify_after_evacuation() { 828 verify_at_safepoint( 829 "After Evacuation", 830 _verify_forwarded_allow, // objects are still forwarded 831 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 832 _verify_cset_forwarded, // all cset refs are fully forwarded 833 _verify_liveness_disable, // no reliable liveness data anymore 834 _verify_regions_notrash, // trash regions have been recycled already 835 _verify_gcstate_forwarded // evacuation produced some forwarded objects 836 ); 837 } 838 839 void ShenandoahVerifier::verify_before_updaterefs() { 840 verify_at_safepoint( 841 "Before Updating References", 842 _verify_forwarded_allow, // forwarded references allowed 843 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 844 _verify_cset_forwarded, // all cset refs are fully forwarded 845 _verify_liveness_disable, // no reliable liveness data anymore 846 _verify_regions_notrash, // trash regions have been recycled already 847 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects 848 ); 849 } 850 851 void ShenandoahVerifier::verify_after_updaterefs() { 852 verify_at_safepoint( 853 "After Updating References", 854 _verify_forwarded_none, // no forwarded references 855 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well 856 _verify_cset_none, // no cset references, all updated 857 _verify_liveness_disable, // no reliable liveness data anymore 858 _verify_regions_nocset, // no cset regions, trash regions have appeared 859 _verify_gcstate_stable // update refs had cleaned up forwarded objects 860 ); 861 } 862 863 void ShenandoahVerifier::verify_after_degenerated() { 864 verify_at_safepoint( 865 "After Degenerated GC", 866 _verify_forwarded_none, // all objects are non-forwarded 867 _verify_marked_complete, // all objects are marked in complete bitmap 868 _verify_cset_none, // no cset references 869 _verify_liveness_disable, // no reliable liveness data anymore 870 _verify_regions_notrash_nocset, // no trash, no cset 871 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects 872 ); 873 } 874 875 void ShenandoahVerifier::verify_before_traversal() { 876 verify_at_safepoint( 877 "Before Traversal", 878 _verify_forwarded_none, // cannot have forwarded objects 879 _verify_marked_disable, // bitmaps are not relevant before traversal 880 _verify_cset_none, // no cset references before traversal 881 _verify_liveness_disable, // no reliable liveness data anymore 882 _verify_regions_notrash_nocset, // no trash and no cset regions 883 _verify_gcstate_stable // nothing forwarded before traversal 884 ); 885 } 886 887 void ShenandoahVerifier::verify_after_traversal() { 888 verify_at_safepoint( 889 "After Traversal", 890 _verify_forwarded_none, // cannot have forwarded objects 891 _verify_marked_complete, // should have complete marking after traversal 892 _verify_cset_none, // no cset references left after traversal 893 _verify_liveness_disable, // liveness data is not collected for new allocations 894 _verify_regions_nocset, // no cset regions, trash regions allowed 895 _verify_gcstate_stable // nothing forwarded after traversal 896 ); 897 } 898 899 void ShenandoahVerifier::verify_before_fullgc() { 900 verify_at_safepoint( 901 "Before Full GC", 902 _verify_forwarded_allow, // can have forwarded objects 903 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations 904 _verify_cset_disable, // cset might be foobared 905 _verify_liveness_disable, // no reliable liveness data anymore 906 _verify_regions_disable, // no reliable region data here 907 _verify_gcstate_disable // no reliable gcstate data 908 ); 909 } 910 911 void ShenandoahVerifier::verify_after_fullgc() { 912 verify_at_safepoint( 913 "After Full GC", 914 _verify_forwarded_none, // all objects are non-forwarded 915 _verify_marked_complete, // all objects are marked in complete bitmap 916 _verify_cset_none, // no cset references 917 _verify_liveness_disable, // no reliable liveness data anymore 918 _verify_regions_notrash_nocset, // no trash, no cset 919 _verify_gcstate_stable // full gc cleaned up everything 920 ); 921 } 922 923 class ShenandoahVerifyNoForwared : public OopClosure { 924 private: 925 template <class T> 926 void do_oop_work(T* p) { 927 T o = RawAccess<>::oop_load(p); 928 if (!CompressedOops::is_null(o)) { 929 oop obj = CompressedOops::decode_not_null(o); 930 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 931 if (!oopDesc::equals_raw(obj, fwd)) { 932 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL, 933 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__); 934 } 935 } 936 } 937 938 public: 939 void do_oop(narrowOop* p) { do_oop_work(p); } 940 void do_oop(oop* p) { do_oop_work(p); } 941 }; 942 943 void ShenandoahVerifier::verify_roots_no_forwarded() { 944 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens"); 945 ShenandoahRootProcessor rp(_heap, 1, ShenandoahPhaseTimings::_num_phases); // no need for stats 946 ShenandoahVerifyNoForwared cl; 947 rp.process_all_roots_slow(&cl); 948 } 949