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