1 /* 2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "code/nmethod.hpp" 27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" 28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 29 #include "gc_implementation/g1/g1OopClosures.inline.hpp" 30 #include "gc_implementation/g1/heapRegion.inline.hpp" 31 #include "gc_implementation/g1/heapRegionBounds.inline.hpp" 32 #include "gc_implementation/g1/heapRegionRemSet.hpp" 33 #include "gc_implementation/g1/heapRegionManager.inline.hpp" 34 #include "gc_implementation/shared/liveRange.hpp" 35 #include "memory/genOopClosures.inline.hpp" 36 #include "memory/iterator.hpp" 37 #include "memory/space.inline.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "runtime/atomic.inline.hpp" 40 #include "runtime/orderAccess.inline.hpp" 41 42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 43 44 int HeapRegion::LogOfHRGrainBytes = 0; 45 int HeapRegion::LogOfHRGrainWords = 0; 46 size_t HeapRegion::GrainBytes = 0; 47 size_t HeapRegion::GrainWords = 0; 48 size_t HeapRegion::CardsPerRegion = 0; 49 50 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1, 51 HeapRegion* hr, 52 G1ParPushHeapRSClosure* cl, 53 CardTableModRefBS::PrecisionStyle precision) : 54 DirtyCardToOopClosure(hr, cl, precision, NULL), 55 _hr(hr), _rs_scan(cl), _g1(g1) { } 56 57 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 58 OopClosure* oc) : 59 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { } 60 61 void HeapRegionDCTOC::walk_mem_region(MemRegion mr, 62 HeapWord* bottom, 63 HeapWord* top) { 64 G1CollectedHeap* g1h = _g1; 65 size_t oop_size; 66 HeapWord* cur = bottom; 67 68 // Start filtering what we add to the remembered set. If the object is 69 // not considered dead, either because it is marked (in the mark bitmap) 70 // or it was allocated after marking finished, then we add it. Otherwise 71 // we can safely ignore the object. 72 if (!g1h->is_obj_dead(oop(cur), _hr)) { 73 oop_size = oop(cur)->oop_iterate(_rs_scan, mr); 74 } else { 75 oop_size = _hr->block_size(cur); 76 } 77 78 cur += oop_size; 79 80 if (cur < top) { 81 oop cur_oop = oop(cur); 82 oop_size = _hr->block_size(cur); 83 HeapWord* next_obj = cur + oop_size; 84 while (next_obj < top) { 85 // Keep filtering the remembered set. 86 if (!g1h->is_obj_dead(cur_oop, _hr)) { 87 // Bottom lies entirely below top, so we can call the 88 // non-memRegion version of oop_iterate below. 89 cur_oop->oop_iterate(_rs_scan); 90 } 91 cur = next_obj; 92 cur_oop = oop(cur); 93 oop_size = _hr->block_size(cur); 94 next_obj = cur + oop_size; 95 } 96 97 // Last object. Need to do dead-obj filtering here too. 98 if (!g1h->is_obj_dead(oop(cur), _hr)) { 99 oop(cur)->oop_iterate(_rs_scan, mr); 100 } 101 } 102 } 103 104 size_t HeapRegion::max_region_size() { 105 return HeapRegionBounds::max_size(); 106 } 107 108 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) { 109 uintx region_size = G1HeapRegionSize; 110 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 111 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2; 112 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(), 113 (uintx) HeapRegionBounds::min_size()); 114 } 115 116 int region_size_log = log2_long((jlong) region_size); 117 // Recalculate the region size to make sure it's a power of 118 // 2. This means that region_size is the largest power of 2 that's 119 // <= what we've calculated so far. 120 region_size = ((uintx)1 << region_size_log); 121 122 // Now make sure that we don't go over or under our limits. 123 if (region_size < HeapRegionBounds::min_size()) { 124 region_size = HeapRegionBounds::min_size(); 125 } else if (region_size > HeapRegionBounds::max_size()) { 126 region_size = HeapRegionBounds::max_size(); 127 } 128 129 // And recalculate the log. 130 region_size_log = log2_long((jlong) region_size); 131 132 // Now, set up the globals. 133 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 134 LogOfHRGrainBytes = region_size_log; 135 136 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 137 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 138 139 guarantee(GrainBytes == 0, "we should only set it once"); 140 // The cast to int is safe, given that we've bounded region_size by 141 // MIN_REGION_SIZE and MAX_REGION_SIZE. 142 GrainBytes = (size_t)region_size; 143 144 guarantee(GrainWords == 0, "we should only set it once"); 145 GrainWords = GrainBytes >> LogHeapWordSize; 146 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity"); 147 148 guarantee(CardsPerRegion == 0, "we should only set it once"); 149 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; 150 } 151 152 void HeapRegion::reset_after_compaction() { 153 G1OffsetTableContigSpace::reset_after_compaction(); 154 // After a compaction the mark bitmap is invalid, so we must 155 // treat all objects as being inside the unmarked area. 156 zero_marked_bytes(); 157 init_top_at_mark_start(); 158 } 159 160 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) { 161 assert(_humongous_start_region == NULL, 162 "we should have already filtered out humongous regions"); 163 assert(_end == orig_end(), 164 "we should have already filtered out humongous regions"); 165 assert(!in_collection_set(), 166 err_msg("Should not clear heap region %u in the collection set", hrm_index())); 167 168 set_allocation_context(AllocationContext::system()); 169 set_young_index_in_cset(-1); 170 uninstall_surv_rate_group(); 171 set_free(); 172 reset_pre_dummy_top(); 173 174 if (!par) { 175 // If this is parallel, this will be done later. 176 HeapRegionRemSet* hrrs = rem_set(); 177 if (locked) { 178 hrrs->clear_locked(); 179 } else { 180 hrrs->clear(); 181 } 182 } 183 zero_marked_bytes(); 184 185 _offsets.resize(HeapRegion::GrainWords); 186 init_top_at_mark_start(); 187 if (clear_space) clear(SpaceDecorator::Mangle); 188 } 189 190 void HeapRegion::par_clear() { 191 assert(used() == 0, "the region should have been already cleared"); 192 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal"); 193 HeapRegionRemSet* hrrs = rem_set(); 194 hrrs->clear(); 195 CardTableModRefBS* ct_bs = 196 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set()); 197 ct_bs->clear(MemRegion(bottom(), end())); 198 } 199 200 void HeapRegion::calc_gc_efficiency() { 201 // GC efficiency is the ratio of how much space would be 202 // reclaimed over how long we predict it would take to reclaim it. 203 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 204 G1CollectorPolicy* g1p = g1h->g1_policy(); 205 206 // Retrieve a prediction of the elapsed time for this region for 207 // a mixed gc because the region will only be evacuated during a 208 // mixed gc. 209 double region_elapsed_time_ms = 210 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */); 211 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms; 212 } 213 214 void HeapRegion::set_starts_humongous(HeapWord* new_top, HeapWord* new_end) { 215 assert(!is_humongous(), "sanity / pre-condition"); 216 assert(end() == orig_end(), 217 "Should be normal before the humongous object allocation"); 218 assert(top() == bottom(), "should be empty"); 219 assert(bottom() <= new_top && new_top <= new_end, "pre-condition"); 220 221 _type.set_starts_humongous(); 222 _humongous_start_region = this; 223 224 set_end(new_end); 225 _offsets.set_for_starts_humongous(new_top); 226 } 227 228 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) { 229 assert(!is_humongous(), "sanity / pre-condition"); 230 assert(end() == orig_end(), 231 "Should be normal before the humongous object allocation"); 232 assert(top() == bottom(), "should be empty"); 233 assert(first_hr->is_starts_humongous(), "pre-condition"); 234 235 _type.set_continues_humongous(); 236 _humongous_start_region = first_hr; 237 } 238 239 void HeapRegion::clear_humongous() { 240 assert(is_humongous(), "pre-condition"); 241 242 if (is_starts_humongous()) { 243 assert(top() <= end(), "pre-condition"); 244 set_end(orig_end()); 245 if (top() > end()) { 246 // at least one "continues humongous" region after it 247 set_top(end()); 248 } 249 } else { 250 // continues humongous 251 assert(end() == orig_end(), "sanity"); 252 } 253 254 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 255 _humongous_start_region = NULL; 256 } 257 258 HeapRegion::HeapRegion(uint hrm_index, 259 G1BlockOffsetSharedArray* sharedOffsetArray, 260 MemRegion mr) : 261 G1OffsetTableContigSpace(sharedOffsetArray, mr), 262 _hrm_index(hrm_index), 263 _allocation_context(AllocationContext::system()), 264 _humongous_start_region(NULL), 265 _next_in_special_set(NULL), 266 _evacuation_failed(false), 267 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), 268 _next_young_region(NULL), 269 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), 270 #ifdef ASSERT 271 _containing_set(NULL), 272 #endif // ASSERT 273 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 274 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 275 _predicted_bytes_to_copy(0) 276 { 277 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this); 278 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant."); 279 280 initialize(mr); 281 } 282 283 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 284 assert(_rem_set->is_empty(), "Remembered set must be empty"); 285 286 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space); 287 288 hr_clear(false /*par*/, false /*clear_space*/); 289 set_top(bottom()); 290 record_timestamp(); 291 292 assert(mr.end() == orig_end(), 293 err_msg("Given region end address " PTR_FORMAT " should match exactly " 294 "bottom plus one region size, i.e. " PTR_FORMAT, 295 p2i(mr.end()), p2i(orig_end()))); 296 } 297 298 CompactibleSpace* HeapRegion::next_compaction_space() const { 299 return G1CollectedHeap::heap()->next_compaction_region(this); 300 } 301 302 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark, 303 bool during_conc_mark) { 304 // We always recreate the prev marking info and we'll explicitly 305 // mark all objects we find to be self-forwarded on the prev 306 // bitmap. So all objects need to be below PTAMS. 307 _prev_marked_bytes = 0; 308 309 if (during_initial_mark) { 310 // During initial-mark, we'll also explicitly mark all objects 311 // we find to be self-forwarded on the next bitmap. So all 312 // objects need to be below NTAMS. 313 _next_top_at_mark_start = top(); 314 _next_marked_bytes = 0; 315 } else if (during_conc_mark) { 316 // During concurrent mark, all objects in the CSet (including 317 // the ones we find to be self-forwarded) are implicitly live. 318 // So all objects need to be above NTAMS. 319 _next_top_at_mark_start = bottom(); 320 _next_marked_bytes = 0; 321 } 322 } 323 324 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark, 325 bool during_conc_mark, 326 size_t marked_bytes) { 327 assert(0 <= marked_bytes && marked_bytes <= used(), 328 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT, 329 marked_bytes, used())); 330 _prev_top_at_mark_start = top(); 331 _prev_marked_bytes = marked_bytes; 332 } 333 334 HeapWord* 335 HeapRegion::object_iterate_mem_careful(MemRegion mr, 336 ObjectClosure* cl) { 337 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 338 // We used to use "block_start_careful" here. But we're actually happy 339 // to update the BOT while we do this... 340 HeapWord* cur = block_start(mr.start()); 341 mr = mr.intersection(used_region()); 342 if (mr.is_empty()) return NULL; 343 // Otherwise, find the obj that extends onto mr.start(). 344 345 assert(cur <= mr.start() 346 && (oop(cur)->klass_or_null() == NULL || 347 cur + oop(cur)->size() > mr.start()), 348 "postcondition of block_start"); 349 oop obj; 350 while (cur < mr.end()) { 351 obj = oop(cur); 352 if (obj->klass_or_null() == NULL) { 353 // Ran into an unparseable point. 354 return cur; 355 } else if (!g1h->is_obj_dead(obj)) { 356 cl->do_object(obj); 357 } 358 cur += block_size(cur); 359 } 360 return NULL; 361 } 362 363 HeapWord* 364 HeapRegion:: 365 oops_on_card_seq_iterate_careful(MemRegion mr, 366 FilterOutOfRegionClosure* cl, 367 bool filter_young, 368 jbyte* card_ptr) { 369 // Currently, we should only have to clean the card if filter_young 370 // is true and vice versa. 371 if (filter_young) { 372 assert(card_ptr != NULL, "pre-condition"); 373 } else { 374 assert(card_ptr == NULL, "pre-condition"); 375 } 376 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 377 378 // If we're within a stop-world GC, then we might look at a card in a 379 // GC alloc region that extends onto a GC LAB, which may not be 380 // parseable. Stop such at the "scan_top" of the region. 381 if (g1h->is_gc_active()) { 382 mr = mr.intersection(MemRegion(bottom(), scan_top())); 383 } else { 384 mr = mr.intersection(used_region()); 385 } 386 if (mr.is_empty()) return NULL; 387 // Otherwise, find the obj that extends onto mr.start(). 388 389 // The intersection of the incoming mr (for the card) and the 390 // allocated part of the region is non-empty. This implies that 391 // we have actually allocated into this region. The code in 392 // G1CollectedHeap.cpp that allocates a new region sets the 393 // is_young tag on the region before allocating. Thus we 394 // safely know if this region is young. 395 if (is_young() && filter_young) { 396 return NULL; 397 } 398 399 assert(!is_young(), "check value of filter_young"); 400 401 // We can only clean the card here, after we make the decision that 402 // the card is not young. And we only clean the card if we have been 403 // asked to (i.e., card_ptr != NULL). 404 if (card_ptr != NULL) { 405 *card_ptr = CardTableModRefBS::clean_card_val(); 406 // We must complete this write before we do any of the reads below. 407 OrderAccess::storeload(); 408 } 409 410 // Cache the boundaries of the memory region in some const locals 411 HeapWord* const start = mr.start(); 412 HeapWord* const end = mr.end(); 413 414 // We used to use "block_start_careful" here. But we're actually happy 415 // to update the BOT while we do this... 416 HeapWord* cur = block_start(start); 417 assert(cur <= start, "Postcondition"); 418 419 oop obj; 420 421 HeapWord* next = cur; 422 do { 423 cur = next; 424 obj = oop(cur); 425 if (obj->klass_or_null() == NULL) { 426 // Ran into an unparseable point. 427 return cur; 428 } 429 // Otherwise... 430 next = cur + block_size(cur); 431 } while (next <= start); 432 433 // If we finish the above loop...We have a parseable object that 434 // begins on or before the start of the memory region, and ends 435 // inside or spans the entire region. 436 assert(cur <= start, "Loop postcondition"); 437 assert(obj->klass_or_null() != NULL, "Loop postcondition"); 438 439 do { 440 obj = oop(cur); 441 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant"); 442 if (obj->klass_or_null() == NULL) { 443 // Ran into an unparseable point. 444 return cur; 445 } 446 447 // Advance the current pointer. "obj" still points to the object to iterate. 448 cur = cur + block_size(cur); 449 450 if (!g1h->is_obj_dead(obj)) { 451 // Non-objArrays are sometimes marked imprecise at the object start. We 452 // always need to iterate over them in full. 453 // We only iterate over object arrays in full if they are completely contained 454 // in the memory region. 455 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) { 456 obj->oop_iterate(cl); 457 } else { 458 obj->oop_iterate(cl, mr); 459 } 460 } 461 } while (cur < end); 462 463 return NULL; 464 } 465 466 // Code roots support 467 468 void HeapRegion::add_strong_code_root(nmethod* nm) { 469 HeapRegionRemSet* hrrs = rem_set(); 470 hrrs->add_strong_code_root(nm); 471 } 472 473 void HeapRegion::add_strong_code_root_locked(nmethod* nm) { 474 assert_locked_or_safepoint(CodeCache_lock); 475 HeapRegionRemSet* hrrs = rem_set(); 476 hrrs->add_strong_code_root_locked(nm); 477 } 478 479 void HeapRegion::remove_strong_code_root(nmethod* nm) { 480 HeapRegionRemSet* hrrs = rem_set(); 481 hrrs->remove_strong_code_root(nm); 482 } 483 484 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const { 485 HeapRegionRemSet* hrrs = rem_set(); 486 hrrs->strong_code_roots_do(blk); 487 } 488 489 class VerifyStrongCodeRootOopClosure: public OopClosure { 490 const HeapRegion* _hr; 491 nmethod* _nm; 492 bool _failures; 493 bool _has_oops_in_region; 494 495 template <class T> void do_oop_work(T* p) { 496 T heap_oop = oopDesc::load_heap_oop(p); 497 if (!oopDesc::is_null(heap_oop)) { 498 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 499 500 // Note: not all the oops embedded in the nmethod are in the 501 // current region. We only look at those which are. 502 if (_hr->is_in(obj)) { 503 // Object is in the region. Check that its less than top 504 if (_hr->top() <= (HeapWord*)obj) { 505 // Object is above top 506 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region " 507 "["PTR_FORMAT", "PTR_FORMAT") is above " 508 "top "PTR_FORMAT, 509 (void *)obj, _hr->bottom(), _hr->end(), _hr->top()); 510 _failures = true; 511 return; 512 } 513 // Nmethod has at least one oop in the current region 514 _has_oops_in_region = true; 515 } 516 } 517 } 518 519 public: 520 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm): 521 _hr(hr), _failures(false), _has_oops_in_region(false) {} 522 523 void do_oop(narrowOop* p) { do_oop_work(p); } 524 void do_oop(oop* p) { do_oop_work(p); } 525 526 bool failures() { return _failures; } 527 bool has_oops_in_region() { return _has_oops_in_region; } 528 }; 529 530 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure { 531 const HeapRegion* _hr; 532 bool _failures; 533 public: 534 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) : 535 _hr(hr), _failures(false) {} 536 537 void do_code_blob(CodeBlob* cb) { 538 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null(); 539 if (nm != NULL) { 540 // Verify that the nemthod is live 541 if (!nm->is_alive()) { 542 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod " 543 PTR_FORMAT" in its strong code roots", 544 _hr->bottom(), _hr->end(), nm); 545 _failures = true; 546 } else { 547 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm); 548 nm->oops_do(&oop_cl); 549 if (!oop_cl.has_oops_in_region()) { 550 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod " 551 PTR_FORMAT" in its strong code roots " 552 "with no pointers into region", 553 _hr->bottom(), _hr->end(), nm); 554 _failures = true; 555 } else if (oop_cl.failures()) { 556 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other " 557 "failures for nmethod "PTR_FORMAT, 558 _hr->bottom(), _hr->end(), nm); 559 _failures = true; 560 } 561 } 562 } 563 } 564 565 bool failures() { return _failures; } 566 }; 567 568 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const { 569 if (!G1VerifyHeapRegionCodeRoots) { 570 // We're not verifying code roots. 571 return; 572 } 573 if (vo == VerifyOption_G1UseMarkWord) { 574 // Marking verification during a full GC is performed after class 575 // unloading, code cache unloading, etc so the strong code roots 576 // attached to each heap region are in an inconsistent state. They won't 577 // be consistent until the strong code roots are rebuilt after the 578 // actual GC. Skip verifying the strong code roots in this particular 579 // time. 580 assert(VerifyDuringGC, "only way to get here"); 581 return; 582 } 583 584 HeapRegionRemSet* hrrs = rem_set(); 585 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length(); 586 587 // if this region is empty then there should be no entries 588 // on its strong code root list 589 if (is_empty()) { 590 if (strong_code_roots_length > 0) { 591 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty " 592 "but has "SIZE_FORMAT" code root entries", 593 bottom(), end(), strong_code_roots_length); 594 *failures = true; 595 } 596 return; 597 } 598 599 if (is_continues_humongous()) { 600 if (strong_code_roots_length > 0) { 601 gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous " 602 "region but has "SIZE_FORMAT" code root entries", 603 HR_FORMAT_PARAMS(this), strong_code_roots_length); 604 *failures = true; 605 } 606 return; 607 } 608 609 VerifyStrongCodeRootCodeBlobClosure cb_cl(this); 610 strong_code_roots_do(&cb_cl); 611 612 if (cb_cl.failures()) { 613 *failures = true; 614 } 615 } 616 617 void HeapRegion::print() const { print_on(gclog_or_tty); } 618 void HeapRegion::print_on(outputStream* st) const { 619 st->print("AC%4u", allocation_context()); 620 621 st->print(" %2s", get_short_type_str()); 622 if (in_collection_set()) 623 st->print(" CS"); 624 else 625 st->print(" "); 626 st->print(" TS %5d", _gc_time_stamp); 627 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT, 628 prev_top_at_mark_start(), next_top_at_mark_start()); 629 G1OffsetTableContigSpace::print_on(st); 630 } 631 632 class VerifyLiveClosure: public OopClosure { 633 private: 634 G1CollectedHeap* _g1h; 635 CardTableModRefBS* _bs; 636 oop _containing_obj; 637 bool _failures; 638 int _n_failures; 639 VerifyOption _vo; 640 public: 641 // _vo == UsePrevMarking -> use "prev" marking information, 642 // _vo == UseNextMarking -> use "next" marking information, 643 // _vo == UseMarkWord -> use mark word from object header. 644 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : 645 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())), 646 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) 647 { } 648 649 void set_containing_obj(oop obj) { 650 _containing_obj = obj; 651 } 652 653 bool failures() { return _failures; } 654 int n_failures() { return _n_failures; } 655 656 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 657 virtual void do_oop( oop* p) { do_oop_work(p); } 658 659 void print_object(outputStream* out, oop obj) { 660 #ifdef PRODUCT 661 Klass* k = obj->klass(); 662 const char* class_name = InstanceKlass::cast(k)->external_name(); 663 out->print_cr("class name %s", class_name); 664 #else // PRODUCT 665 obj->print_on(out); 666 #endif // PRODUCT 667 } 668 669 template <class T> 670 void do_oop_work(T* p) { 671 assert(_containing_obj != NULL, "Precondition"); 672 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 673 "Precondition"); 674 T heap_oop = oopDesc::load_heap_oop(p); 675 if (!oopDesc::is_null(heap_oop)) { 676 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 677 bool failed = false; 678 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) { 679 MutexLockerEx x(ParGCRareEvent_lock, 680 Mutex::_no_safepoint_check_flag); 681 682 if (!_failures) { 683 gclog_or_tty->cr(); 684 gclog_or_tty->print_cr("----------"); 685 } 686 if (!_g1h->is_in_closed_subset(obj)) { 687 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 688 gclog_or_tty->print_cr("Field "PTR_FORMAT 689 " of live obj "PTR_FORMAT" in region " 690 "["PTR_FORMAT", "PTR_FORMAT")", 691 p, (void*) _containing_obj, 692 from->bottom(), from->end()); 693 print_object(gclog_or_tty, _containing_obj); 694 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap", 695 (void*) obj); 696 } else { 697 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 698 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 699 gclog_or_tty->print_cr("Field "PTR_FORMAT 700 " of live obj "PTR_FORMAT" in region " 701 "["PTR_FORMAT", "PTR_FORMAT")", 702 p, (void*) _containing_obj, 703 from->bottom(), from->end()); 704 print_object(gclog_or_tty, _containing_obj); 705 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region " 706 "["PTR_FORMAT", "PTR_FORMAT")", 707 (void*) obj, to->bottom(), to->end()); 708 print_object(gclog_or_tty, obj); 709 } 710 gclog_or_tty->print_cr("----------"); 711 gclog_or_tty->flush(); 712 _failures = true; 713 failed = true; 714 _n_failures++; 715 } 716 717 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) { 718 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 719 HeapRegion* to = _g1h->heap_region_containing(obj); 720 if (from != NULL && to != NULL && 721 from != to && 722 !to->is_humongous()) { 723 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 724 jbyte cv_field = *_bs->byte_for_const(p); 725 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 726 727 bool is_bad = !(from->is_young() 728 || to->rem_set()->contains_reference(p) 729 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 730 (_containing_obj->is_objArray() ? 731 cv_field == dirty 732 : cv_obj == dirty || cv_field == dirty)); 733 if (is_bad) { 734 MutexLockerEx x(ParGCRareEvent_lock, 735 Mutex::_no_safepoint_check_flag); 736 737 if (!_failures) { 738 gclog_or_tty->cr(); 739 gclog_or_tty->print_cr("----------"); 740 } 741 gclog_or_tty->print_cr("Missing rem set entry:"); 742 gclog_or_tty->print_cr("Field "PTR_FORMAT" " 743 "of obj "PTR_FORMAT", " 744 "in region "HR_FORMAT, 745 p, (void*) _containing_obj, 746 HR_FORMAT_PARAMS(from)); 747 _containing_obj->print_on(gclog_or_tty); 748 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" " 749 "in region "HR_FORMAT, 750 (void*) obj, 751 HR_FORMAT_PARAMS(to)); 752 obj->print_on(gclog_or_tty); 753 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.", 754 cv_obj, cv_field); 755 gclog_or_tty->print_cr("----------"); 756 gclog_or_tty->flush(); 757 _failures = true; 758 if (!failed) _n_failures++; 759 } 760 } 761 } 762 } 763 } 764 }; 765 766 // This really ought to be commoned up into OffsetTableContigSpace somehow. 767 // We would need a mechanism to make that code skip dead objects. 768 769 void HeapRegion::verify(VerifyOption vo, 770 bool* failures) const { 771 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 772 *failures = false; 773 HeapWord* p = bottom(); 774 HeapWord* prev_p = NULL; 775 VerifyLiveClosure vl_cl(g1, vo); 776 bool is_region_humongous = is_humongous(); 777 size_t object_num = 0; 778 while (p < top()) { 779 oop obj = oop(p); 780 size_t obj_size = block_size(p); 781 object_num += 1; 782 783 if (is_region_humongous != g1->is_humongous(obj_size) && 784 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects. 785 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size (" 786 SIZE_FORMAT" words) in a %shumongous region", 787 p, g1->is_humongous(obj_size) ? "" : "non-", 788 obj_size, is_region_humongous ? "" : "non-"); 789 *failures = true; 790 return; 791 } 792 793 if (!g1->is_obj_dead_cond(obj, this, vo)) { 794 if (obj->is_oop()) { 795 Klass* klass = obj->klass(); 796 bool is_metaspace_object = Metaspace::contains(klass) || 797 (vo == VerifyOption_G1UsePrevMarking && 798 ClassLoaderDataGraph::unload_list_contains(klass)); 799 if (!is_metaspace_object) { 800 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 801 "not metadata", klass, (void *)obj); 802 *failures = true; 803 return; 804 } else if (!klass->is_klass()) { 805 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 806 "not a klass", klass, (void *)obj); 807 *failures = true; 808 return; 809 } else { 810 vl_cl.set_containing_obj(obj); 811 obj->oop_iterate_no_header(&vl_cl); 812 if (vl_cl.failures()) { 813 *failures = true; 814 } 815 if (G1MaxVerifyFailures >= 0 && 816 vl_cl.n_failures() >= G1MaxVerifyFailures) { 817 return; 818 } 819 } 820 } else { 821 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj); 822 *failures = true; 823 return; 824 } 825 } 826 prev_p = p; 827 p += obj_size; 828 } 829 830 if (!is_young() && !is_empty()) { 831 _offsets.verify(); 832 } 833 834 if (p != top()) { 835 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" " 836 "does not match top "PTR_FORMAT, p, top()); 837 *failures = true; 838 return; 839 } 840 841 HeapWord* the_end = end(); 842 assert(p == top(), "it should still hold"); 843 // Do some extra BOT consistency checking for addresses in the 844 // range [top, end). BOT look-ups in this range should yield 845 // top. No point in doing that if top == end (there's nothing there). 846 if (p < the_end) { 847 // Look up top 848 HeapWord* addr_1 = p; 849 HeapWord* b_start_1 = _offsets.block_start_const(addr_1); 850 if (b_start_1 != p) { 851 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" " 852 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 853 addr_1, b_start_1, p); 854 *failures = true; 855 return; 856 } 857 858 // Look up top + 1 859 HeapWord* addr_2 = p + 1; 860 if (addr_2 < the_end) { 861 HeapWord* b_start_2 = _offsets.block_start_const(addr_2); 862 if (b_start_2 != p) { 863 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" " 864 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 865 addr_2, b_start_2, p); 866 *failures = true; 867 return; 868 } 869 } 870 871 // Look up an address between top and end 872 size_t diff = pointer_delta(the_end, p) / 2; 873 HeapWord* addr_3 = p + diff; 874 if (addr_3 < the_end) { 875 HeapWord* b_start_3 = _offsets.block_start_const(addr_3); 876 if (b_start_3 != p) { 877 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" " 878 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 879 addr_3, b_start_3, p); 880 *failures = true; 881 return; 882 } 883 } 884 885 // Look up end - 1 886 HeapWord* addr_4 = the_end - 1; 887 HeapWord* b_start_4 = _offsets.block_start_const(addr_4); 888 if (b_start_4 != p) { 889 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" " 890 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 891 addr_4, b_start_4, p); 892 *failures = true; 893 return; 894 } 895 } 896 897 if (is_region_humongous && object_num > 1) { 898 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous " 899 "but has "SIZE_FORMAT", objects", 900 bottom(), end(), object_num); 901 *failures = true; 902 return; 903 } 904 905 verify_strong_code_roots(vo, failures); 906 } 907 908 void HeapRegion::verify() const { 909 bool dummy = false; 910 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 911 } 912 913 void HeapRegion::prepare_for_compaction(CompactPoint* cp) { 914 scan_and_forward(this, cp); 915 } 916 917 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 918 // away eventually. 919 920 void G1OffsetTableContigSpace::clear(bool mangle_space) { 921 set_top(bottom()); 922 _scan_top = bottom(); 923 CompactibleSpace::clear(mangle_space); 924 reset_bot(); 925 } 926 927 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 928 Space::set_bottom(new_bottom); 929 _offsets.set_bottom(new_bottom); 930 } 931 932 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) { 933 Space::set_end(new_end); 934 _offsets.resize(new_end - bottom()); 935 } 936 937 #ifndef PRODUCT 938 void G1OffsetTableContigSpace::mangle_unused_area() { 939 mangle_unused_area_complete(); 940 } 941 942 void G1OffsetTableContigSpace::mangle_unused_area_complete() { 943 SpaceMangler::mangle_region(MemRegion(top(), end())); 944 } 945 #endif 946 947 void G1OffsetTableContigSpace::print() const { 948 print_short(); 949 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 950 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 951 bottom(), top(), _offsets.threshold(), end()); 952 } 953 954 HeapWord* G1OffsetTableContigSpace::initialize_threshold() { 955 return _offsets.initialize_threshold(); 956 } 957 958 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start, 959 HeapWord* end) { 960 _offsets.alloc_block(start, end); 961 return _offsets.threshold(); 962 } 963 964 HeapWord* G1OffsetTableContigSpace::scan_top() const { 965 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 966 HeapWord* local_top = top(); 967 OrderAccess::loadload(); 968 const unsigned local_time_stamp = _gc_time_stamp; 969 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant"); 970 if (local_time_stamp < g1h->get_gc_time_stamp()) { 971 return local_top; 972 } else { 973 return _scan_top; 974 } 975 } 976 977 void G1OffsetTableContigSpace::record_timestamp() { 978 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 979 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 980 981 if (_gc_time_stamp < curr_gc_time_stamp) { 982 // Setting the time stamp here tells concurrent readers to look at 983 // scan_top to know the maximum allowed address to look at. 984 985 // scan_top should be bottom for all regions except for the 986 // retained old alloc region which should have scan_top == top 987 HeapWord* st = _scan_top; 988 guarantee(st == _bottom || st == _top, "invariant"); 989 990 _gc_time_stamp = curr_gc_time_stamp; 991 } 992 } 993 994 void G1OffsetTableContigSpace::record_retained_region() { 995 // scan_top is the maximum address where it's safe for the next gc to 996 // scan this region. 997 _scan_top = top(); 998 } 999 1000 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) { 1001 object_iterate(blk); 1002 } 1003 1004 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) { 1005 HeapWord* p = bottom(); 1006 while (p < top()) { 1007 if (block_is_obj(p)) { 1008 blk->do_object(oop(p)); 1009 } 1010 p += block_size(p); 1011 } 1012 } 1013 1014 G1OffsetTableContigSpace:: 1015 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 1016 MemRegion mr) : 1017 _offsets(sharedOffsetArray, mr), 1018 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 1019 _gc_time_stamp(0) 1020 { 1021 _offsets.set_space(this); 1022 } 1023 1024 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 1025 CompactibleSpace::initialize(mr, clear_space, mangle_space); 1026 _top = bottom(); 1027 _scan_top = bottom(); 1028 set_saved_mark_word(NULL); 1029 reset_bot(); 1030 } 1031