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/g1/g1BlockOffsetTable.inline.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.hpp" 29 #include "gc/g1/g1OopClosures.inline.hpp" 30 #include "gc/g1/heapRegion.inline.hpp" 31 #include "gc/g1/heapRegionBounds.inline.hpp" 32 #include "gc/g1/heapRegionManager.inline.hpp" 33 #include "gc/g1/heapRegionRemSet.hpp" 34 #include "gc/shared/genOopClosures.inline.hpp" 35 #include "gc/shared/liveRange.hpp" 36 #include "gc/shared/space.inline.hpp" 37 #include "memory/iterator.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "runtime/atomic.inline.hpp" 40 #include "runtime/orderAccess.inline.hpp" 41 42 int HeapRegion::LogOfHRGrainBytes = 0; 43 int HeapRegion::LogOfHRGrainWords = 0; 44 size_t HeapRegion::GrainBytes = 0; 45 size_t HeapRegion::GrainWords = 0; 46 size_t HeapRegion::CardsPerRegion = 0; 47 48 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1, 49 HeapRegion* hr, 50 G1ParPushHeapRSClosure* cl, 51 CardTableModRefBS::PrecisionStyle precision) : 52 DirtyCardToOopClosure(hr, cl, precision, NULL), 53 _hr(hr), _rs_scan(cl), _g1(g1) { } 54 55 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 56 OopClosure* oc) : 57 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { } 58 59 void HeapRegionDCTOC::walk_mem_region(MemRegion mr, 60 HeapWord* bottom, 61 HeapWord* top) { 62 G1CollectedHeap* g1h = _g1; 63 size_t oop_size; 64 HeapWord* cur = bottom; 65 66 // Start filtering what we add to the remembered set. If the object is 67 // not considered dead, either because it is marked (in the mark bitmap) 68 // or it was allocated after marking finished, then we add it. Otherwise 69 // we can safely ignore the object. 70 if (!g1h->is_obj_dead(oop(cur), _hr)) { 71 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr); 72 } else { 73 oop_size = _hr->block_size(cur); 74 } 75 76 cur += oop_size; 77 78 if (cur < top) { 79 oop cur_oop = oop(cur); 80 oop_size = _hr->block_size(cur); 81 HeapWord* next_obj = cur + oop_size; 82 while (next_obj < top) { 83 // Keep filtering the remembered set. 84 if (!g1h->is_obj_dead(cur_oop, _hr)) { 85 // Bottom lies entirely below top, so we can call the 86 // non-memRegion version of oop_iterate below. 87 cur_oop->oop_iterate(_rs_scan); 88 } 89 cur = next_obj; 90 cur_oop = oop(cur); 91 oop_size = _hr->block_size(cur); 92 next_obj = cur + oop_size; 93 } 94 95 // Last object. Need to do dead-obj filtering here too. 96 if (!g1h->is_obj_dead(oop(cur), _hr)) { 97 oop(cur)->oop_iterate(_rs_scan, mr); 98 } 99 } 100 } 101 102 size_t HeapRegion::max_region_size() { 103 return HeapRegionBounds::max_size(); 104 } 105 106 size_t HeapRegion::min_region_size_in_words() { 107 return HeapRegionBounds::min_size() >> LogHeapWordSize; 108 } 109 110 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) { 111 size_t region_size = G1HeapRegionSize; 112 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 113 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2; 114 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(), 115 HeapRegionBounds::min_size()); 116 } 117 118 int region_size_log = log2_long((jlong) region_size); 119 // Recalculate the region size to make sure it's a power of 120 // 2. This means that region_size is the largest power of 2 that's 121 // <= what we've calculated so far. 122 region_size = ((size_t)1 << region_size_log); 123 124 // Now make sure that we don't go over or under our limits. 125 if (region_size < HeapRegionBounds::min_size()) { 126 region_size = HeapRegionBounds::min_size(); 127 } else if (region_size > HeapRegionBounds::max_size()) { 128 region_size = HeapRegionBounds::max_size(); 129 } 130 131 // And recalculate the log. 132 region_size_log = log2_long((jlong) region_size); 133 134 // Now, set up the globals. 135 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 136 LogOfHRGrainBytes = region_size_log; 137 138 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 139 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 140 141 guarantee(GrainBytes == 0, "we should only set it once"); 142 // The cast to int is safe, given that we've bounded region_size by 143 // MIN_REGION_SIZE and MAX_REGION_SIZE. 144 GrainBytes = region_size; 145 146 guarantee(GrainWords == 0, "we should only set it once"); 147 GrainWords = GrainBytes >> LogHeapWordSize; 148 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity"); 149 150 guarantee(CardsPerRegion == 0, "we should only set it once"); 151 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; 152 } 153 154 void HeapRegion::reset_after_compaction() { 155 G1OffsetTableContigSpace::reset_after_compaction(); 156 // After a compaction the mark bitmap is invalid, so we must 157 // treat all objects as being inside the unmarked area. 158 zero_marked_bytes(); 159 init_top_at_mark_start(); 160 } 161 162 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) { 163 assert(_humongous_start_region == NULL, 164 "we should have already filtered out humongous regions"); 165 assert(_end == orig_end(), 166 "we should have already filtered out humongous regions"); 167 assert(!in_collection_set(), 168 err_msg("Should not clear heap region %u in the collection set", hrm_index())); 169 170 set_allocation_context(AllocationContext::system()); 171 set_young_index_in_cset(-1); 172 uninstall_surv_rate_group(); 173 set_free(); 174 reset_pre_dummy_top(); 175 176 if (!par) { 177 // If this is parallel, this will be done later. 178 HeapRegionRemSet* hrrs = rem_set(); 179 if (locked) { 180 hrrs->clear_locked(); 181 } else { 182 hrrs->clear(); 183 } 184 } 185 zero_marked_bytes(); 186 187 _offsets.resize(HeapRegion::GrainWords); 188 init_top_at_mark_start(); 189 if (clear_space) clear(SpaceDecorator::Mangle); 190 } 191 192 void HeapRegion::par_clear() { 193 assert(used() == 0, "the region should have been already cleared"); 194 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal"); 195 HeapRegionRemSet* hrrs = rem_set(); 196 hrrs->clear(); 197 CardTableModRefBS* ct_bs = 198 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set()); 199 ct_bs->clear(MemRegion(bottom(), end())); 200 } 201 202 void HeapRegion::calc_gc_efficiency() { 203 // GC efficiency is the ratio of how much space would be 204 // reclaimed over how long we predict it would take to reclaim it. 205 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 206 G1CollectorPolicy* g1p = g1h->g1_policy(); 207 208 // Retrieve a prediction of the elapsed time for this region for 209 // a mixed gc because the region will only be evacuated during a 210 // mixed gc. 211 double region_elapsed_time_ms = 212 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */); 213 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms; 214 } 215 216 void HeapRegion::set_starts_humongous(HeapWord* new_top, HeapWord* new_end) { 217 assert(!is_humongous(), "sanity / pre-condition"); 218 assert(end() == orig_end(), 219 "Should be normal before the humongous object allocation"); 220 assert(top() == bottom(), "should be empty"); 221 assert(bottom() <= new_top && new_top <= new_end, "pre-condition"); 222 223 _type.set_starts_humongous(); 224 _humongous_start_region = this; 225 226 set_end(new_end); 227 _offsets.set_for_starts_humongous(new_top); 228 } 229 230 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) { 231 assert(!is_humongous(), "sanity / pre-condition"); 232 assert(end() == orig_end(), 233 "Should be normal before the humongous object allocation"); 234 assert(top() == bottom(), "should be empty"); 235 assert(first_hr->is_starts_humongous(), "pre-condition"); 236 237 _type.set_continues_humongous(); 238 _humongous_start_region = first_hr; 239 } 240 241 void HeapRegion::clear_humongous() { 242 assert(is_humongous(), "pre-condition"); 243 244 if (is_starts_humongous()) { 245 assert(top() <= end(), "pre-condition"); 246 set_end(orig_end()); 247 if (top() > end()) { 248 // at least one "continues humongous" region after it 249 set_top(end()); 250 } 251 } else { 252 // continues humongous 253 assert(end() == orig_end(), "sanity"); 254 } 255 256 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 257 _humongous_start_region = NULL; 258 } 259 260 HeapRegion::HeapRegion(uint hrm_index, 261 G1BlockOffsetSharedArray* sharedOffsetArray, 262 MemRegion mr) : 263 G1OffsetTableContigSpace(sharedOffsetArray, mr), 264 _hrm_index(hrm_index), 265 _allocation_context(AllocationContext::system()), 266 _humongous_start_region(NULL), 267 _next_in_special_set(NULL), 268 _evacuation_failed(false), 269 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), 270 _next_young_region(NULL), 271 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), 272 #ifdef ASSERT 273 _containing_set(NULL), 274 #endif // ASSERT 275 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 276 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 277 _predicted_bytes_to_copy(0) 278 { 279 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this); 280 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant."); 281 282 initialize(mr); 283 } 284 285 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 286 assert(_rem_set->is_empty(), "Remembered set must be empty"); 287 288 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space); 289 290 hr_clear(false /*par*/, false /*clear_space*/); 291 set_top(bottom()); 292 record_timestamp(); 293 294 assert(mr.end() == orig_end(), 295 err_msg("Given region end address " PTR_FORMAT " should match exactly " 296 "bottom plus one region size, i.e. " PTR_FORMAT, 297 p2i(mr.end()), p2i(orig_end()))); 298 } 299 300 CompactibleSpace* HeapRegion::next_compaction_space() const { 301 return G1CollectedHeap::heap()->next_compaction_region(this); 302 } 303 304 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark, 305 bool during_conc_mark) { 306 // We always recreate the prev marking info and we'll explicitly 307 // mark all objects we find to be self-forwarded on the prev 308 // bitmap. So all objects need to be below PTAMS. 309 _prev_marked_bytes = 0; 310 311 if (during_initial_mark) { 312 // During initial-mark, we'll also explicitly mark all objects 313 // we find to be self-forwarded on the next bitmap. So all 314 // objects need to be below NTAMS. 315 _next_top_at_mark_start = top(); 316 _next_marked_bytes = 0; 317 } else if (during_conc_mark) { 318 // During concurrent mark, all objects in the CSet (including 319 // the ones we find to be self-forwarded) are implicitly live. 320 // So all objects need to be above NTAMS. 321 _next_top_at_mark_start = bottom(); 322 _next_marked_bytes = 0; 323 } 324 } 325 326 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark, 327 bool during_conc_mark, 328 size_t marked_bytes) { 329 assert(marked_bytes <= used(), 330 err_msg("marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used())); 331 _prev_top_at_mark_start = top(); 332 _prev_marked_bytes = marked_bytes; 333 } 334 335 HeapWord* 336 HeapRegion::object_iterate_mem_careful(MemRegion mr, 337 ObjectClosure* cl) { 338 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 339 // We used to use "block_start_careful" here. But we're actually happy 340 // to update the BOT while we do this... 341 HeapWord* cur = block_start(mr.start()); 342 mr = mr.intersection(used_region()); 343 if (mr.is_empty()) return NULL; 344 // Otherwise, find the obj that extends onto mr.start(). 345 346 assert(cur <= mr.start() 347 && (oop(cur)->klass_or_null() == NULL || 348 cur + oop(cur)->size() > mr.start()), 349 "postcondition of block_start"); 350 oop obj; 351 while (cur < mr.end()) { 352 obj = oop(cur); 353 if (obj->klass_or_null() == NULL) { 354 // Ran into an unparseable point. 355 return cur; 356 } else if (!g1h->is_obj_dead(obj)) { 357 cl->do_object(obj); 358 } 359 cur += block_size(cur); 360 } 361 return NULL; 362 } 363 364 HeapWord* 365 HeapRegion:: 366 oops_on_card_seq_iterate_careful(MemRegion mr, 367 FilterOutOfRegionClosure* cl, 368 bool filter_young, 369 jbyte* card_ptr) { 370 // Currently, we should only have to clean the card if filter_young 371 // is true and vice versa. 372 if (filter_young) { 373 assert(card_ptr != NULL, "pre-condition"); 374 } else { 375 assert(card_ptr == NULL, "pre-condition"); 376 } 377 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 378 379 // If we're within a stop-world GC, then we might look at a card in a 380 // GC alloc region that extends onto a GC LAB, which may not be 381 // parseable. Stop such at the "scan_top" of the region. 382 if (g1h->is_gc_active()) { 383 mr = mr.intersection(MemRegion(bottom(), scan_top())); 384 } else { 385 mr = mr.intersection(used_region()); 386 } 387 if (mr.is_empty()) return NULL; 388 // Otherwise, find the obj that extends onto mr.start(). 389 390 // The intersection of the incoming mr (for the card) and the 391 // allocated part of the region is non-empty. This implies that 392 // we have actually allocated into this region. The code in 393 // G1CollectedHeap.cpp that allocates a new region sets the 394 // is_young tag on the region before allocating. Thus we 395 // safely know if this region is young. 396 if (is_young() && filter_young) { 397 return NULL; 398 } 399 400 assert(!is_young(), "check value of filter_young"); 401 402 // We can only clean the card here, after we make the decision that 403 // the card is not young. And we only clean the card if we have been 404 // asked to (i.e., card_ptr != NULL). 405 if (card_ptr != NULL) { 406 *card_ptr = CardTableModRefBS::clean_card_val(); 407 // We must complete this write before we do any of the reads below. 408 OrderAccess::storeload(); 409 } 410 411 // Cache the boundaries of the memory region in some const locals 412 HeapWord* const start = mr.start(); 413 HeapWord* const end = mr.end(); 414 415 // We used to use "block_start_careful" here. But we're actually happy 416 // to update the BOT while we do this... 417 HeapWord* cur = block_start(start); 418 assert(cur <= start, "Postcondition"); 419 420 oop obj; 421 422 HeapWord* next = cur; 423 do { 424 cur = next; 425 obj = oop(cur); 426 if (obj->klass_or_null() == NULL) { 427 // Ran into an unparseable point. 428 return cur; 429 } 430 // Otherwise... 431 next = cur + block_size(cur); 432 } while (next <= start); 433 434 // If we finish the above loop...We have a parseable object that 435 // begins on or before the start of the memory region, and ends 436 // inside or spans the entire region. 437 assert(cur <= start, "Loop postcondition"); 438 assert(obj->klass_or_null() != NULL, "Loop postcondition"); 439 440 do { 441 obj = oop(cur); 442 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant"); 443 if (obj->klass_or_null() == NULL) { 444 // Ran into an unparseable point. 445 return cur; 446 } 447 448 // Advance the current pointer. "obj" still points to the object to iterate. 449 cur = cur + block_size(cur); 450 451 if (!g1h->is_obj_dead(obj)) { 452 // Non-objArrays are sometimes marked imprecise at the object start. We 453 // always need to iterate over them in full. 454 // We only iterate over object arrays in full if they are completely contained 455 // in the memory region. 456 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) { 457 obj->oop_iterate(cl); 458 } else { 459 obj->oop_iterate(cl, mr); 460 } 461 } 462 } while (cur < end); 463 464 return NULL; 465 } 466 467 // Code roots support 468 469 void HeapRegion::add_strong_code_root(nmethod* nm) { 470 HeapRegionRemSet* hrrs = rem_set(); 471 hrrs->add_strong_code_root(nm); 472 } 473 474 void HeapRegion::add_strong_code_root_locked(nmethod* nm) { 475 assert_locked_or_safepoint(CodeCache_lock); 476 HeapRegionRemSet* hrrs = rem_set(); 477 hrrs->add_strong_code_root_locked(nm); 478 } 479 480 void HeapRegion::remove_strong_code_root(nmethod* nm) { 481 HeapRegionRemSet* hrrs = rem_set(); 482 hrrs->remove_strong_code_root(nm); 483 } 484 485 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const { 486 HeapRegionRemSet* hrrs = rem_set(); 487 hrrs->strong_code_roots_do(blk); 488 } 489 490 class VerifyStrongCodeRootOopClosure: public OopClosure { 491 const HeapRegion* _hr; 492 nmethod* _nm; 493 bool _failures; 494 bool _has_oops_in_region; 495 496 template <class T> void do_oop_work(T* p) { 497 T heap_oop = oopDesc::load_heap_oop(p); 498 if (!oopDesc::is_null(heap_oop)) { 499 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 500 501 // Note: not all the oops embedded in the nmethod are in the 502 // current region. We only look at those which are. 503 if (_hr->is_in(obj)) { 504 // Object is in the region. Check that its less than top 505 if (_hr->top() <= (HeapWord*)obj) { 506 // Object is above top 507 gclog_or_tty->print_cr("Object " PTR_FORMAT " in region " 508 "[" PTR_FORMAT ", " PTR_FORMAT ") is above " 509 "top " PTR_FORMAT, 510 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top())); 511 _failures = true; 512 return; 513 } 514 // Nmethod has at least one oop in the current region 515 _has_oops_in_region = true; 516 } 517 } 518 } 519 520 public: 521 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm): 522 _hr(hr), _failures(false), _has_oops_in_region(false) {} 523 524 void do_oop(narrowOop* p) { do_oop_work(p); } 525 void do_oop(oop* p) { do_oop_work(p); } 526 527 bool failures() { return _failures; } 528 bool has_oops_in_region() { return _has_oops_in_region; } 529 }; 530 531 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure { 532 const HeapRegion* _hr; 533 bool _failures; 534 public: 535 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) : 536 _hr(hr), _failures(false) {} 537 538 void do_code_blob(CodeBlob* cb) { 539 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null(); 540 if (nm != NULL) { 541 // Verify that the nemthod is live 542 if (!nm->is_alive()) { 543 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " 544 PTR_FORMAT " in its strong code roots", 545 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 546 _failures = true; 547 } else { 548 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm); 549 nm->oops_do(&oop_cl); 550 if (!oop_cl.has_oops_in_region()) { 551 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " 552 PTR_FORMAT " in its strong code roots " 553 "with no pointers into region", 554 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 555 _failures = true; 556 } else if (oop_cl.failures()) { 557 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has other " 558 "failures for nmethod " PTR_FORMAT, 559 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 560 _failures = true; 561 } 562 } 563 } 564 } 565 566 bool failures() { return _failures; } 567 }; 568 569 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const { 570 if (!G1VerifyHeapRegionCodeRoots) { 571 // We're not verifying code roots. 572 return; 573 } 574 if (vo == VerifyOption_G1UseMarkWord) { 575 // Marking verification during a full GC is performed after class 576 // unloading, code cache unloading, etc so the strong code roots 577 // attached to each heap region are in an inconsistent state. They won't 578 // be consistent until the strong code roots are rebuilt after the 579 // actual GC. Skip verifying the strong code roots in this particular 580 // time. 581 assert(VerifyDuringGC, "only way to get here"); 582 return; 583 } 584 585 HeapRegionRemSet* hrrs = rem_set(); 586 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length(); 587 588 // if this region is empty then there should be no entries 589 // on its strong code root list 590 if (is_empty()) { 591 if (strong_code_roots_length > 0) { 592 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is empty " 593 "but has " SIZE_FORMAT " code root entries", 594 p2i(bottom()), p2i(end()), strong_code_roots_length); 595 *failures = true; 596 } 597 return; 598 } 599 600 if (is_continues_humongous()) { 601 if (strong_code_roots_length > 0) { 602 gclog_or_tty->print_cr("region " HR_FORMAT " is a continuation of a humongous " 603 "region but has " SIZE_FORMAT " code root entries", 604 HR_FORMAT_PARAMS(this), strong_code_roots_length); 605 *failures = true; 606 } 607 return; 608 } 609 610 VerifyStrongCodeRootCodeBlobClosure cb_cl(this); 611 strong_code_roots_do(&cb_cl); 612 613 if (cb_cl.failures()) { 614 *failures = true; 615 } 616 } 617 618 void HeapRegion::print() const { print_on(gclog_or_tty); } 619 void HeapRegion::print_on(outputStream* st) const { 620 st->print("AC%4u", allocation_context()); 621 622 st->print(" %2s", get_short_type_str()); 623 if (in_collection_set()) 624 st->print(" CS"); 625 else 626 st->print(" "); 627 st->print(" TS %5d", _gc_time_stamp); 628 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT, 629 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start())); 630 G1OffsetTableContigSpace::print_on(st); 631 } 632 633 class VerifyLiveClosure: public OopClosure { 634 private: 635 G1CollectedHeap* _g1h; 636 CardTableModRefBS* _bs; 637 oop _containing_obj; 638 bool _failures; 639 int _n_failures; 640 VerifyOption _vo; 641 public: 642 // _vo == UsePrevMarking -> use "prev" marking information, 643 // _vo == UseNextMarking -> use "next" marking information, 644 // _vo == UseMarkWord -> use mark word from object header. 645 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : 646 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())), 647 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) 648 { } 649 650 void set_containing_obj(oop obj) { 651 _containing_obj = obj; 652 } 653 654 bool failures() { return _failures; } 655 int n_failures() { return _n_failures; } 656 657 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 658 virtual void do_oop( oop* p) { do_oop_work(p); } 659 660 void print_object(outputStream* out, oop obj) { 661 #ifdef PRODUCT 662 Klass* k = obj->klass(); 663 const char* class_name = InstanceKlass::cast(k)->external_name(); 664 out->print_cr("class name %s", class_name); 665 #else // PRODUCT 666 obj->print_on(out); 667 #endif // PRODUCT 668 } 669 670 template <class T> 671 void do_oop_work(T* p) { 672 assert(_containing_obj != NULL, "Precondition"); 673 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 674 "Precondition"); 675 T heap_oop = oopDesc::load_heap_oop(p); 676 if (!oopDesc::is_null(heap_oop)) { 677 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 678 bool failed = false; 679 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) { 680 MutexLockerEx x(ParGCRareEvent_lock, 681 Mutex::_no_safepoint_check_flag); 682 683 if (!_failures) { 684 gclog_or_tty->cr(); 685 gclog_or_tty->print_cr("----------"); 686 } 687 if (!_g1h->is_in_closed_subset(obj)) { 688 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 689 gclog_or_tty->print_cr("Field " PTR_FORMAT 690 " of live obj " PTR_FORMAT " in region " 691 "[" PTR_FORMAT ", " PTR_FORMAT ")", 692 p2i(p), p2i(_containing_obj), 693 p2i(from->bottom()), p2i(from->end())); 694 print_object(gclog_or_tty, _containing_obj); 695 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " not in the heap", 696 p2i(obj)); 697 } else { 698 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 699 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 700 gclog_or_tty->print_cr("Field " PTR_FORMAT 701 " of live obj " PTR_FORMAT " in region " 702 "[" PTR_FORMAT ", " PTR_FORMAT ")", 703 p2i(p), p2i(_containing_obj), 704 p2i(from->bottom()), p2i(from->end())); 705 print_object(gclog_or_tty, _containing_obj); 706 gclog_or_tty->print_cr("points to dead obj " PTR_FORMAT " in region " 707 "[" PTR_FORMAT ", " PTR_FORMAT ")", 708 p2i(obj), p2i(to->bottom()), p2i(to->end())); 709 print_object(gclog_or_tty, obj); 710 } 711 gclog_or_tty->print_cr("----------"); 712 gclog_or_tty->flush(); 713 _failures = true; 714 failed = true; 715 _n_failures++; 716 } 717 718 if (!_g1h->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) { 719 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 720 HeapRegion* to = _g1h->heap_region_containing(obj); 721 if (from != NULL && to != NULL && 722 from != to && 723 !to->is_pinned()) { 724 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 725 jbyte cv_field = *_bs->byte_for_const(p); 726 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 727 728 bool is_bad = !(from->is_young() 729 || to->rem_set()->contains_reference(p) 730 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 731 (_containing_obj->is_objArray() ? 732 cv_field == dirty 733 : cv_obj == dirty || cv_field == dirty)); 734 if (is_bad) { 735 MutexLockerEx x(ParGCRareEvent_lock, 736 Mutex::_no_safepoint_check_flag); 737 738 if (!_failures) { 739 gclog_or_tty->cr(); 740 gclog_or_tty->print_cr("----------"); 741 } 742 gclog_or_tty->print_cr("Missing rem set entry:"); 743 gclog_or_tty->print_cr("Field " PTR_FORMAT " " 744 "of obj " PTR_FORMAT ", " 745 "in region " HR_FORMAT, 746 p2i(p), p2i(_containing_obj), 747 HR_FORMAT_PARAMS(from)); 748 _containing_obj->print_on(gclog_or_tty); 749 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " " 750 "in region " HR_FORMAT, 751 p2i(obj), 752 HR_FORMAT_PARAMS(to)); 753 obj->print_on(gclog_or_tty); 754 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.", 755 cv_obj, cv_field); 756 gclog_or_tty->print_cr("----------"); 757 gclog_or_tty->flush(); 758 _failures = true; 759 if (!failed) _n_failures++; 760 } 761 } 762 } 763 } 764 } 765 }; 766 767 // This really ought to be commoned up into OffsetTableContigSpace somehow. 768 // We would need a mechanism to make that code skip dead objects. 769 770 void HeapRegion::verify(VerifyOption vo, 771 bool* failures) const { 772 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 773 *failures = false; 774 HeapWord* p = bottom(); 775 HeapWord* prev_p = NULL; 776 VerifyLiveClosure vl_cl(g1, vo); 777 bool is_region_humongous = is_humongous(); 778 size_t object_num = 0; 779 while (p < top()) { 780 oop obj = oop(p); 781 size_t obj_size = block_size(p); 782 object_num += 1; 783 784 if (is_region_humongous != g1->is_humongous(obj_size) && 785 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects. 786 gclog_or_tty->print_cr("obj " PTR_FORMAT " is of %shumongous size (" 787 SIZE_FORMAT " words) in a %shumongous region", 788 p2i(p), g1->is_humongous(obj_size) ? "" : "non-", 789 obj_size, is_region_humongous ? "" : "non-"); 790 *failures = true; 791 return; 792 } 793 794 if (!g1->is_obj_dead_cond(obj, this, vo)) { 795 if (obj->is_oop()) { 796 Klass* klass = obj->klass(); 797 bool is_metaspace_object = Metaspace::contains(klass) || 798 (vo == VerifyOption_G1UsePrevMarking && 799 ClassLoaderDataGraph::unload_list_contains(klass)); 800 if (!is_metaspace_object) { 801 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " " 802 "not metadata", p2i(klass), p2i(obj)); 803 *failures = true; 804 return; 805 } else if (!klass->is_klass()) { 806 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " " 807 "not a klass", p2i(klass), p2i(obj)); 808 *failures = true; 809 return; 810 } else { 811 vl_cl.set_containing_obj(obj); 812 obj->oop_iterate_no_header(&vl_cl); 813 if (vl_cl.failures()) { 814 *failures = true; 815 } 816 if (G1MaxVerifyFailures >= 0 && 817 vl_cl.n_failures() >= G1MaxVerifyFailures) { 818 return; 819 } 820 } 821 } else { 822 gclog_or_tty->print_cr(PTR_FORMAT " no an oop", p2i(obj)); 823 *failures = true; 824 return; 825 } 826 } 827 prev_p = p; 828 p += obj_size; 829 } 830 831 if (!is_young() && !is_empty()) { 832 _offsets.verify(); 833 } 834 835 if (p != top()) { 836 gclog_or_tty->print_cr("end of last object " PTR_FORMAT " " 837 "does not match top " PTR_FORMAT, p2i(p), p2i(top())); 838 *failures = true; 839 return; 840 } 841 842 HeapWord* the_end = end(); 843 assert(p == top(), "it should still hold"); 844 // Do some extra BOT consistency checking for addresses in the 845 // range [top, end). BOT look-ups in this range should yield 846 // top. No point in doing that if top == end (there's nothing there). 847 if (p < the_end) { 848 // Look up top 849 HeapWord* addr_1 = p; 850 HeapWord* b_start_1 = _offsets.block_start_const(addr_1); 851 if (b_start_1 != p) { 852 gclog_or_tty->print_cr("BOT look up for top: " PTR_FORMAT " " 853 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 854 p2i(addr_1), p2i(b_start_1), p2i(p)); 855 *failures = true; 856 return; 857 } 858 859 // Look up top + 1 860 HeapWord* addr_2 = p + 1; 861 if (addr_2 < the_end) { 862 HeapWord* b_start_2 = _offsets.block_start_const(addr_2); 863 if (b_start_2 != p) { 864 gclog_or_tty->print_cr("BOT look up for top + 1: " PTR_FORMAT " " 865 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 866 p2i(addr_2), p2i(b_start_2), p2i(p)); 867 *failures = true; 868 return; 869 } 870 } 871 872 // Look up an address between top and end 873 size_t diff = pointer_delta(the_end, p) / 2; 874 HeapWord* addr_3 = p + diff; 875 if (addr_3 < the_end) { 876 HeapWord* b_start_3 = _offsets.block_start_const(addr_3); 877 if (b_start_3 != p) { 878 gclog_or_tty->print_cr("BOT look up for top + diff: " PTR_FORMAT " " 879 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 880 p2i(addr_3), p2i(b_start_3), p2i(p)); 881 *failures = true; 882 return; 883 } 884 } 885 886 // Look up end - 1 887 HeapWord* addr_4 = the_end - 1; 888 HeapWord* b_start_4 = _offsets.block_start_const(addr_4); 889 if (b_start_4 != p) { 890 gclog_or_tty->print_cr("BOT look up for end - 1: " PTR_FORMAT " " 891 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 892 p2i(addr_4), p2i(b_start_4), p2i(p)); 893 *failures = true; 894 return; 895 } 896 } 897 898 if (is_region_humongous && object_num > 1) { 899 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is humongous " 900 "but has " SIZE_FORMAT ", objects", 901 p2i(bottom()), p2i(end()), object_num); 902 *failures = true; 903 return; 904 } 905 906 verify_strong_code_roots(vo, failures); 907 } 908 909 void HeapRegion::verify() const { 910 bool dummy = false; 911 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 912 } 913 914 void HeapRegion::prepare_for_compaction(CompactPoint* cp) { 915 scan_and_forward(this, cp); 916 } 917 918 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 919 // away eventually. 920 921 void G1OffsetTableContigSpace::clear(bool mangle_space) { 922 set_top(bottom()); 923 _scan_top = bottom(); 924 CompactibleSpace::clear(mangle_space); 925 reset_bot(); 926 } 927 928 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 929 Space::set_bottom(new_bottom); 930 _offsets.set_bottom(new_bottom); 931 } 932 933 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) { 934 Space::set_end(new_end); 935 _offsets.resize(new_end - bottom()); 936 } 937 938 #ifndef PRODUCT 939 void G1OffsetTableContigSpace::mangle_unused_area() { 940 mangle_unused_area_complete(); 941 } 942 943 void G1OffsetTableContigSpace::mangle_unused_area_complete() { 944 SpaceMangler::mangle_region(MemRegion(top(), end())); 945 } 946 #endif 947 948 void G1OffsetTableContigSpace::print() const { 949 print_short(); 950 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 951 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 952 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end())); 953 } 954 955 HeapWord* G1OffsetTableContigSpace::initialize_threshold() { 956 return _offsets.initialize_threshold(); 957 } 958 959 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start, 960 HeapWord* end) { 961 _offsets.alloc_block(start, end); 962 return _offsets.threshold(); 963 } 964 965 HeapWord* G1OffsetTableContigSpace::scan_top() const { 966 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 967 HeapWord* local_top = top(); 968 OrderAccess::loadload(); 969 const unsigned local_time_stamp = _gc_time_stamp; 970 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant"); 971 if (local_time_stamp < g1h->get_gc_time_stamp()) { 972 return local_top; 973 } else { 974 return _scan_top; 975 } 976 } 977 978 void G1OffsetTableContigSpace::record_timestamp() { 979 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 980 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 981 982 if (_gc_time_stamp < curr_gc_time_stamp) { 983 // Setting the time stamp here tells concurrent readers to look at 984 // scan_top to know the maximum allowed address to look at. 985 986 // scan_top should be bottom for all regions except for the 987 // retained old alloc region which should have scan_top == top 988 HeapWord* st = _scan_top; 989 guarantee(st == _bottom || st == _top, "invariant"); 990 991 _gc_time_stamp = curr_gc_time_stamp; 992 } 993 } 994 995 void G1OffsetTableContigSpace::record_retained_region() { 996 // scan_top is the maximum address where it's safe for the next gc to 997 // scan this region. 998 _scan_top = top(); 999 } 1000 1001 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) { 1002 object_iterate(blk); 1003 } 1004 1005 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) { 1006 HeapWord* p = bottom(); 1007 while (p < top()) { 1008 if (block_is_obj(p)) { 1009 blk->do_object(oop(p)); 1010 } 1011 p += block_size(p); 1012 } 1013 } 1014 1015 G1OffsetTableContigSpace:: 1016 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 1017 MemRegion mr) : 1018 _offsets(sharedOffsetArray, mr), 1019 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 1020 _gc_time_stamp(0) 1021 { 1022 _offsets.set_space(this); 1023 } 1024 1025 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 1026 CompactibleSpace::initialize(mr, clear_space, mangle_space); 1027 _top = bottom(); 1028 _scan_top = bottom(); 1029 set_saved_mark_word(NULL); 1030 reset_bot(); 1031 } 1032