1 /* 2 * Copyright (c) 2001, 2011, 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 "gc_implementation/g1/g1BlockOffsetTable.inline.hpp" 27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 28 #include "gc_implementation/g1/g1OopClosures.inline.hpp" 29 #include "gc_implementation/g1/heapRegion.inline.hpp" 30 #include "gc_implementation/g1/heapRegionRemSet.hpp" 31 #include "gc_implementation/g1/heapRegionSeq.inline.hpp" 32 #include "memory/genOopClosures.inline.hpp" 33 #include "memory/iterator.hpp" 34 #include "oops/oop.inline.hpp" 35 36 int HeapRegion::LogOfHRGrainBytes = 0; 37 int HeapRegion::LogOfHRGrainWords = 0; 38 size_t HeapRegion::GrainBytes = 0; 39 size_t HeapRegion::GrainWords = 0; 40 size_t HeapRegion::CardsPerRegion = 0; 41 42 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1, 43 HeapRegion* hr, OopClosure* cl, 44 CardTableModRefBS::PrecisionStyle precision, 45 FilterKind fk) : 46 ContiguousSpaceDCTOC(hr, cl, precision, NULL), 47 _hr(hr), _fk(fk), _g1(g1) 48 { } 49 50 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 51 OopClosure* oc) : 52 _r_bottom(r->bottom()), _r_end(r->end()), 53 _oc(oc), _out_of_region(0) 54 {} 55 56 class VerifyLiveClosure: public OopClosure { 57 private: 58 G1CollectedHeap* _g1h; 59 CardTableModRefBS* _bs; 60 oop _containing_obj; 61 bool _failures; 62 int _n_failures; 63 VerifyOption _vo; 64 public: 65 // _vo == UsePrevMarking -> use "prev" marking information, 66 // _vo == UseNextMarking -> use "next" marking information, 67 // _vo == UseMarkWord -> use mark word from object header. 68 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : 69 _g1h(g1h), _bs(NULL), _containing_obj(NULL), 70 _failures(false), _n_failures(0), _vo(vo) 71 { 72 BarrierSet* bs = _g1h->barrier_set(); 73 if (bs->is_a(BarrierSet::CardTableModRef)) 74 _bs = (CardTableModRefBS*)bs; 75 } 76 77 void set_containing_obj(oop obj) { 78 _containing_obj = obj; 79 } 80 81 bool failures() { return _failures; } 82 int n_failures() { return _n_failures; } 83 84 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 85 virtual void do_oop( oop* p) { do_oop_work(p); } 86 87 void print_object(outputStream* out, oop obj) { 88 #ifdef PRODUCT 89 klassOop k = obj->klass(); 90 const char* class_name = instanceKlass::cast(k)->external_name(); 91 out->print_cr("class name %s", class_name); 92 #else // PRODUCT 93 obj->print_on(out); 94 #endif // PRODUCT 95 } 96 97 template <class T> void do_oop_work(T* p) { 98 assert(_containing_obj != NULL, "Precondition"); 99 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 100 "Precondition"); 101 T heap_oop = oopDesc::load_heap_oop(p); 102 if (!oopDesc::is_null(heap_oop)) { 103 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 104 bool failed = false; 105 if (!_g1h->is_in_closed_subset(obj) || 106 _g1h->is_obj_dead_cond(obj, _vo)) { 107 if (!_failures) { 108 gclog_or_tty->print_cr(""); 109 gclog_or_tty->print_cr("----------"); 110 } 111 if (!_g1h->is_in_closed_subset(obj)) { 112 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 113 gclog_or_tty->print_cr("Field "PTR_FORMAT 114 " of live obj "PTR_FORMAT" in region " 115 "["PTR_FORMAT", "PTR_FORMAT")", 116 p, (void*) _containing_obj, 117 from->bottom(), from->end()); 118 print_object(gclog_or_tty, _containing_obj); 119 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap", 120 (void*) obj); 121 } else { 122 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 123 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 124 gclog_or_tty->print_cr("Field "PTR_FORMAT 125 " of live obj "PTR_FORMAT" in region " 126 "["PTR_FORMAT", "PTR_FORMAT")", 127 p, (void*) _containing_obj, 128 from->bottom(), from->end()); 129 print_object(gclog_or_tty, _containing_obj); 130 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region " 131 "["PTR_FORMAT", "PTR_FORMAT")", 132 (void*) obj, to->bottom(), to->end()); 133 print_object(gclog_or_tty, obj); 134 } 135 gclog_or_tty->print_cr("----------"); 136 _failures = true; 137 failed = true; 138 _n_failures++; 139 } 140 141 if (!_g1h->full_collection()) { 142 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 143 HeapRegion* to = _g1h->heap_region_containing(obj); 144 if (from != NULL && to != NULL && 145 from != to && 146 !to->isHumongous()) { 147 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 148 jbyte cv_field = *_bs->byte_for_const(p); 149 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 150 151 bool is_bad = !(from->is_young() 152 || to->rem_set()->contains_reference(p) 153 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 154 (_containing_obj->is_objArray() ? 155 cv_field == dirty 156 : cv_obj == dirty || cv_field == dirty)); 157 if (is_bad) { 158 if (!_failures) { 159 gclog_or_tty->print_cr(""); 160 gclog_or_tty->print_cr("----------"); 161 } 162 gclog_or_tty->print_cr("Missing rem set entry:"); 163 gclog_or_tty->print_cr("Field "PTR_FORMAT" " 164 "of obj "PTR_FORMAT", " 165 "in region "HR_FORMAT, 166 p, (void*) _containing_obj, 167 HR_FORMAT_PARAMS(from)); 168 _containing_obj->print_on(gclog_or_tty); 169 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" " 170 "in region "HR_FORMAT, 171 (void*) obj, 172 HR_FORMAT_PARAMS(to)); 173 obj->print_on(gclog_or_tty); 174 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.", 175 cv_obj, cv_field); 176 gclog_or_tty->print_cr("----------"); 177 _failures = true; 178 if (!failed) _n_failures++; 179 } 180 } 181 } 182 } 183 } 184 }; 185 186 template<class ClosureType> 187 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h, 188 HeapRegion* hr, 189 HeapWord* cur, HeapWord* top) { 190 oop cur_oop = oop(cur); 191 int oop_size = cur_oop->size(); 192 HeapWord* next_obj = cur + oop_size; 193 while (next_obj < top) { 194 // Keep filtering the remembered set. 195 if (!g1h->is_obj_dead(cur_oop, hr)) { 196 // Bottom lies entirely below top, so we can call the 197 // non-memRegion version of oop_iterate below. 198 cur_oop->oop_iterate(cl); 199 } 200 cur = next_obj; 201 cur_oop = oop(cur); 202 oop_size = cur_oop->size(); 203 next_obj = cur + oop_size; 204 } 205 return cur; 206 } 207 208 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr, 209 HeapWord* bottom, 210 HeapWord* top, 211 OopClosure* cl) { 212 G1CollectedHeap* g1h = _g1; 213 214 int oop_size; 215 216 OopClosure* cl2 = cl; 217 218 // If we are scanning the remembered sets looking for refs 219 // into the collection set during an evacuation pause then 220 // we will want to 'discover' reference objects that point 221 // to referents in the collection set. 222 // 223 // Unfortunately it is an instance of FilterIntoCSClosure 224 // that is iterated over the reference fields of oops in 225 // mr (and not the G1ParPushHeapRSClosure - which is the 226 // cl parameter). 227 // If we set the _ref_processor field in the FilterIntoCSClosure 228 // instance, all the reference objects that are walked 229 // (regardless of whether their referent object's are in 230 // the cset) will be 'discovered'. 231 // 232 // The G1STWIsAlive closure considers a referent object that 233 // is outside the cset as alive. The G1CopyingKeepAliveClosure 234 // skips referents that are not in the cset. 235 // 236 // Therefore reference objects in mr with a referent that is 237 // outside the cset should be OK. 238 239 ReferenceProcessor* rp = _cl->_ref_processor; 240 if (rp != NULL) { 241 assert(rp == _g1->ref_processor_stw(), "should be stw"); 242 assert(_fk == IntoCSFilterKind, "should be looking for refs into CS"); 243 } 244 245 FilterIntoCSClosure intoCSFilt(this, g1h, cl, rp); 246 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl); 247 248 switch (_fk) { 249 case IntoCSFilterKind: cl2 = &intoCSFilt; break; 250 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break; 251 } 252 253 // Start filtering what we add to the remembered set. If the object is 254 // not considered dead, either because it is marked (in the mark bitmap) 255 // or it was allocated after marking finished, then we add it. Otherwise 256 // we can safely ignore the object. 257 if (!g1h->is_obj_dead(oop(bottom), _hr)) { 258 oop_size = oop(bottom)->oop_iterate(cl2, mr); 259 } else { 260 oop_size = oop(bottom)->size(); 261 } 262 263 bottom += oop_size; 264 265 if (bottom < top) { 266 // We replicate the loop below for several kinds of possible filters. 267 switch (_fk) { 268 case NoFilterKind: 269 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top); 270 break; 271 272 case IntoCSFilterKind: { 273 FilterIntoCSClosure filt(this, g1h, cl, rp); 274 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top); 275 break; 276 } 277 278 case OutOfRegionFilterKind: { 279 FilterOutOfRegionClosure filt(_hr, cl); 280 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top); 281 break; 282 } 283 284 default: 285 ShouldNotReachHere(); 286 } 287 288 // Last object. Need to do dead-obj filtering here too. 289 if (!g1h->is_obj_dead(oop(bottom), _hr)) { 290 oop(bottom)->oop_iterate(cl2, mr); 291 } 292 } 293 } 294 295 // Minimum region size; we won't go lower than that. 296 // We might want to decrease this in the future, to deal with small 297 // heaps a bit more efficiently. 298 #define MIN_REGION_SIZE ( 1024 * 1024 ) 299 300 // Maximum region size; we don't go higher than that. There's a good 301 // reason for having an upper bound. We don't want regions to get too 302 // large, otherwise cleanup's effectiveness would decrease as there 303 // will be fewer opportunities to find totally empty regions after 304 // marking. 305 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 ) 306 307 // The automatic region size calculation will try to have around this 308 // many regions in the heap (based on the min heap size). 309 #define TARGET_REGION_NUMBER 2048 310 311 void HeapRegion::setup_heap_region_size(uintx min_heap_size) { 312 // region_size in bytes 313 uintx region_size = G1HeapRegionSize; 314 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 315 // We base the automatic calculation on the min heap size. This 316 // can be problematic if the spread between min and max is quite 317 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on 318 // the max size, the region size might be way too large for the 319 // min size. Either way, some users might have to set the region 320 // size manually for some -Xms / -Xmx combos. 321 322 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER, 323 (uintx) MIN_REGION_SIZE); 324 } 325 326 int region_size_log = log2_long((jlong) region_size); 327 // Recalculate the region size to make sure it's a power of 328 // 2. This means that region_size is the largest power of 2 that's 329 // <= what we've calculated so far. 330 region_size = ((uintx)1 << region_size_log); 331 332 // Now make sure that we don't go over or under our limits. 333 if (region_size < MIN_REGION_SIZE) { 334 region_size = MIN_REGION_SIZE; 335 } else if (region_size > MAX_REGION_SIZE) { 336 region_size = MAX_REGION_SIZE; 337 } 338 339 // And recalculate the log. 340 region_size_log = log2_long((jlong) region_size); 341 342 // Now, set up the globals. 343 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 344 LogOfHRGrainBytes = region_size_log; 345 346 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 347 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 348 349 guarantee(GrainBytes == 0, "we should only set it once"); 350 // The cast to int is safe, given that we've bounded region_size by 351 // MIN_REGION_SIZE and MAX_REGION_SIZE. 352 GrainBytes = (size_t)region_size; 353 354 guarantee(GrainWords == 0, "we should only set it once"); 355 GrainWords = GrainBytes >> LogHeapWordSize; 356 guarantee((size_t)(1 << LogOfHRGrainWords) == GrainWords, "sanity"); 357 358 guarantee(CardsPerRegion == 0, "we should only set it once"); 359 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; 360 } 361 362 void HeapRegion::reset_after_compaction() { 363 G1OffsetTableContigSpace::reset_after_compaction(); 364 // After a compaction the mark bitmap is invalid, so we must 365 // treat all objects as being inside the unmarked area. 366 zero_marked_bytes(); 367 init_top_at_mark_start(); 368 } 369 370 DirtyCardToOopClosure* 371 HeapRegion::new_dcto_closure(OopClosure* cl, 372 CardTableModRefBS::PrecisionStyle precision, 373 HeapRegionDCTOC::FilterKind fk) { 374 return new HeapRegionDCTOC(G1CollectedHeap::heap(), 375 this, cl, precision, fk); 376 } 377 378 void HeapRegion::hr_clear(bool par, bool clear_space) { 379 assert(_humongous_type == NotHumongous, 380 "we should have already filtered out humongous regions"); 381 assert(_humongous_start_region == NULL, 382 "we should have already filtered out humongous regions"); 383 assert(_end == _orig_end, 384 "we should have already filtered out humongous regions"); 385 386 _in_collection_set = false; 387 388 set_young_index_in_cset(-1); 389 uninstall_surv_rate_group(); 390 set_young_type(NotYoung); 391 reset_pre_dummy_top(); 392 393 if (!par) { 394 // If this is parallel, this will be done later. 395 HeapRegionRemSet* hrrs = rem_set(); 396 if (hrrs != NULL) hrrs->clear(); 397 _claimed = InitialClaimValue; 398 } 399 zero_marked_bytes(); 400 set_sort_index(-1); 401 402 _offsets.resize(HeapRegion::GrainWords); 403 init_top_at_mark_start(); 404 if (clear_space) clear(SpaceDecorator::Mangle); 405 } 406 407 void HeapRegion::par_clear() { 408 assert(used() == 0, "the region should have been already cleared"); 409 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal"); 410 HeapRegionRemSet* hrrs = rem_set(); 411 hrrs->clear(); 412 CardTableModRefBS* ct_bs = 413 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set(); 414 ct_bs->clear(MemRegion(bottom(), end())); 415 } 416 417 // <PREDICTION> 418 void HeapRegion::calc_gc_efficiency() { 419 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 420 _gc_efficiency = (double) garbage_bytes() / 421 g1h->predict_region_elapsed_time_ms(this, false); 422 } 423 // </PREDICTION> 424 425 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) { 426 assert(!isHumongous(), "sanity / pre-condition"); 427 assert(end() == _orig_end, 428 "Should be normal before the humongous object allocation"); 429 assert(top() == bottom(), "should be empty"); 430 assert(bottom() <= new_top && new_top <= new_end, "pre-condition"); 431 432 _humongous_type = StartsHumongous; 433 _humongous_start_region = this; 434 435 set_end(new_end); 436 _offsets.set_for_starts_humongous(new_top); 437 } 438 439 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) { 440 assert(!isHumongous(), "sanity / pre-condition"); 441 assert(end() == _orig_end, 442 "Should be normal before the humongous object allocation"); 443 assert(top() == bottom(), "should be empty"); 444 assert(first_hr->startsHumongous(), "pre-condition"); 445 446 _humongous_type = ContinuesHumongous; 447 _humongous_start_region = first_hr; 448 } 449 450 void HeapRegion::set_notHumongous() { 451 assert(isHumongous(), "pre-condition"); 452 453 if (startsHumongous()) { 454 assert(top() <= end(), "pre-condition"); 455 set_end(_orig_end); 456 if (top() > end()) { 457 // at least one "continues humongous" region after it 458 set_top(end()); 459 } 460 } else { 461 // continues humongous 462 assert(end() == _orig_end, "sanity"); 463 } 464 465 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 466 _humongous_type = NotHumongous; 467 _humongous_start_region = NULL; 468 } 469 470 bool HeapRegion::claimHeapRegion(jint claimValue) { 471 jint current = _claimed; 472 if (current != claimValue) { 473 jint res = Atomic::cmpxchg(claimValue, &_claimed, current); 474 if (res == current) { 475 return true; 476 } 477 } 478 return false; 479 } 480 481 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) { 482 HeapWord* low = addr; 483 HeapWord* high = end(); 484 while (low < high) { 485 size_t diff = pointer_delta(high, low); 486 // Must add one below to bias toward the high amount. Otherwise, if 487 // "high" were at the desired value, and "low" were one less, we 488 // would not converge on "high". This is not symmetric, because 489 // we set "high" to a block start, which might be the right one, 490 // which we don't do for "low". 491 HeapWord* middle = low + (diff+1)/2; 492 if (middle == high) return high; 493 HeapWord* mid_bs = block_start_careful(middle); 494 if (mid_bs < addr) { 495 low = middle; 496 } else { 497 high = mid_bs; 498 } 499 } 500 assert(low == high && low >= addr, "Didn't work."); 501 return low; 502 } 503 504 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 505 G1OffsetTableContigSpace::initialize(mr, false, mangle_space); 506 hr_clear(false/*par*/, clear_space); 507 } 508 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away 509 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 510 #endif // _MSC_VER 511 512 513 HeapRegion:: 514 HeapRegion(size_t hrs_index, G1BlockOffsetSharedArray* sharedOffsetArray, 515 MemRegion mr, bool is_zeroed) 516 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed), 517 _hrs_index(hrs_index), 518 _humongous_type(NotHumongous), _humongous_start_region(NULL), 519 _in_collection_set(false), 520 _next_in_special_set(NULL), _orig_end(NULL), 521 _claimed(InitialClaimValue), _evacuation_failed(false), 522 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1), 523 _gc_efficiency(0.0), 524 _young_type(NotYoung), _next_young_region(NULL), 525 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false), 526 #ifdef ASSERT 527 _containing_set(NULL), 528 #endif // ASSERT 529 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 530 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 531 _predicted_bytes_to_copy(0) 532 { 533 _orig_end = mr.end(); 534 // Note that initialize() will set the start of the unmarked area of the 535 // region. 536 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 537 set_top(bottom()); 538 set_saved_mark(); 539 540 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this); 541 542 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant."); 543 // In case the region is allocated during a pause, note the top. 544 // We haven't done any counting on a brand new region. 545 _top_at_conc_mark_count = bottom(); 546 } 547 548 class NextCompactionHeapRegionClosure: public HeapRegionClosure { 549 const HeapRegion* _target; 550 bool _target_seen; 551 HeapRegion* _last; 552 CompactibleSpace* _res; 553 public: 554 NextCompactionHeapRegionClosure(const HeapRegion* target) : 555 _target(target), _target_seen(false), _res(NULL) {} 556 bool doHeapRegion(HeapRegion* cur) { 557 if (_target_seen) { 558 if (!cur->isHumongous()) { 559 _res = cur; 560 return true; 561 } 562 } else if (cur == _target) { 563 _target_seen = true; 564 } 565 return false; 566 } 567 CompactibleSpace* result() { return _res; } 568 }; 569 570 CompactibleSpace* HeapRegion::next_compaction_space() const { 571 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 572 // cast away const-ness 573 HeapRegion* r = (HeapRegion*) this; 574 NextCompactionHeapRegionClosure blk(r); 575 g1h->heap_region_iterate_from(r, &blk); 576 return blk.result(); 577 } 578 579 void HeapRegion::save_marks() { 580 set_saved_mark(); 581 } 582 583 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) { 584 HeapWord* p = mr.start(); 585 HeapWord* e = mr.end(); 586 oop obj; 587 while (p < e) { 588 obj = oop(p); 589 p += obj->oop_iterate(cl); 590 } 591 assert(p == e, "bad memregion: doesn't end on obj boundary"); 592 } 593 594 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ 595 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ 596 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \ 597 } 598 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN) 599 600 601 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) { 602 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl); 603 } 604 605 HeapWord* 606 HeapRegion::object_iterate_mem_careful(MemRegion mr, 607 ObjectClosure* cl) { 608 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 609 // We used to use "block_start_careful" here. But we're actually happy 610 // to update the BOT while we do this... 611 HeapWord* cur = block_start(mr.start()); 612 mr = mr.intersection(used_region()); 613 if (mr.is_empty()) return NULL; 614 // Otherwise, find the obj that extends onto mr.start(). 615 616 assert(cur <= mr.start() 617 && (oop(cur)->klass_or_null() == NULL || 618 cur + oop(cur)->size() > mr.start()), 619 "postcondition of block_start"); 620 oop obj; 621 while (cur < mr.end()) { 622 obj = oop(cur); 623 if (obj->klass_or_null() == NULL) { 624 // Ran into an unparseable point. 625 return cur; 626 } else if (!g1h->is_obj_dead(obj)) { 627 cl->do_object(obj); 628 } 629 if (cl->abort()) return cur; 630 // The check above must occur before the operation below, since an 631 // abort might invalidate the "size" operation. 632 cur += obj->size(); 633 } 634 return NULL; 635 } 636 637 HeapWord* 638 HeapRegion:: 639 oops_on_card_seq_iterate_careful(MemRegion mr, 640 FilterOutOfRegionClosure* cl, 641 bool filter_young, 642 jbyte* card_ptr) { 643 // Currently, we should only have to clean the card if filter_young 644 // is true and vice versa. 645 if (filter_young) { 646 assert(card_ptr != NULL, "pre-condition"); 647 } else { 648 assert(card_ptr == NULL, "pre-condition"); 649 } 650 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 651 652 // If we're within a stop-world GC, then we might look at a card in a 653 // GC alloc region that extends onto a GC LAB, which may not be 654 // parseable. Stop such at the "saved_mark" of the region. 655 if (G1CollectedHeap::heap()->is_gc_active()) { 656 mr = mr.intersection(used_region_at_save_marks()); 657 } else { 658 mr = mr.intersection(used_region()); 659 } 660 if (mr.is_empty()) return NULL; 661 // Otherwise, find the obj that extends onto mr.start(). 662 663 // The intersection of the incoming mr (for the card) and the 664 // allocated part of the region is non-empty. This implies that 665 // we have actually allocated into this region. The code in 666 // G1CollectedHeap.cpp that allocates a new region sets the 667 // is_young tag on the region before allocating. Thus we 668 // safely know if this region is young. 669 if (is_young() && filter_young) { 670 return NULL; 671 } 672 673 assert(!is_young(), "check value of filter_young"); 674 675 // We can only clean the card here, after we make the decision that 676 // the card is not young. And we only clean the card if we have been 677 // asked to (i.e., card_ptr != NULL). 678 if (card_ptr != NULL) { 679 *card_ptr = CardTableModRefBS::clean_card_val(); 680 // We must complete this write before we do any of the reads below. 681 OrderAccess::storeload(); 682 } 683 684 // We used to use "block_start_careful" here. But we're actually happy 685 // to update the BOT while we do this... 686 HeapWord* cur = block_start(mr.start()); 687 assert(cur <= mr.start(), "Postcondition"); 688 689 while (cur <= mr.start()) { 690 if (oop(cur)->klass_or_null() == NULL) { 691 // Ran into an unparseable point. 692 return cur; 693 } 694 // Otherwise... 695 int sz = oop(cur)->size(); 696 if (cur + sz > mr.start()) break; 697 // Otherwise, go on. 698 cur = cur + sz; 699 } 700 oop obj; 701 obj = oop(cur); 702 // If we finish this loop... 703 assert(cur <= mr.start() 704 && obj->klass_or_null() != NULL 705 && cur + obj->size() > mr.start(), 706 "Loop postcondition"); 707 if (!g1h->is_obj_dead(obj)) { 708 obj->oop_iterate(cl, mr); 709 } 710 711 HeapWord* next; 712 while (cur < mr.end()) { 713 obj = oop(cur); 714 if (obj->klass_or_null() == NULL) { 715 // Ran into an unparseable point. 716 return cur; 717 }; 718 // Otherwise: 719 next = (cur + obj->size()); 720 if (!g1h->is_obj_dead(obj)) { 721 if (next < mr.end()) { 722 obj->oop_iterate(cl); 723 } else { 724 // this obj spans the boundary. If it's an array, stop at the 725 // boundary. 726 if (obj->is_objArray()) { 727 obj->oop_iterate(cl, mr); 728 } else { 729 obj->oop_iterate(cl); 730 } 731 } 732 } 733 cur = next; 734 } 735 return NULL; 736 } 737 738 void HeapRegion::print() const { print_on(gclog_or_tty); } 739 void HeapRegion::print_on(outputStream* st) const { 740 if (isHumongous()) { 741 if (startsHumongous()) 742 st->print(" HS"); 743 else 744 st->print(" HC"); 745 } else { 746 st->print(" "); 747 } 748 if (in_collection_set()) 749 st->print(" CS"); 750 else 751 st->print(" "); 752 if (is_young()) 753 st->print(is_survivor() ? " SU" : " Y "); 754 else 755 st->print(" "); 756 if (is_empty()) 757 st->print(" F"); 758 else 759 st->print(" "); 760 st->print(" %5d", _gc_time_stamp); 761 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT, 762 prev_top_at_mark_start(), next_top_at_mark_start()); 763 G1OffsetTableContigSpace::print_on(st); 764 } 765 766 void HeapRegion::verify(bool allow_dirty) const { 767 bool dummy = false; 768 verify(allow_dirty, VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 769 } 770 771 // This really ought to be commoned up into OffsetTableContigSpace somehow. 772 // We would need a mechanism to make that code skip dead objects. 773 774 void HeapRegion::verify(bool allow_dirty, 775 VerifyOption vo, 776 bool* failures) const { 777 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 778 *failures = false; 779 HeapWord* p = bottom(); 780 HeapWord* prev_p = NULL; 781 VerifyLiveClosure vl_cl(g1, vo); 782 bool is_humongous = isHumongous(); 783 bool do_bot_verify = !is_young(); 784 size_t object_num = 0; 785 while (p < top()) { 786 oop obj = oop(p); 787 size_t obj_size = obj->size(); 788 object_num += 1; 789 790 if (is_humongous != g1->isHumongous(obj_size)) { 791 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size (" 792 SIZE_FORMAT" words) in a %shumongous region", 793 p, g1->isHumongous(obj_size) ? "" : "non-", 794 obj_size, is_humongous ? "" : "non-"); 795 *failures = true; 796 return; 797 } 798 799 // If it returns false, verify_for_object() will output the 800 // appropriate messasge. 801 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) { 802 *failures = true; 803 return; 804 } 805 806 if (!g1->is_obj_dead_cond(obj, this, vo)) { 807 if (obj->is_oop()) { 808 klassOop klass = obj->klass(); 809 if (!klass->is_perm()) { 810 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 811 "not in perm", klass, obj); 812 *failures = true; 813 return; 814 } else if (!klass->is_klass()) { 815 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 816 "not a klass", klass, obj); 817 *failures = true; 818 return; 819 } else { 820 vl_cl.set_containing_obj(obj); 821 obj->oop_iterate(&vl_cl); 822 if (vl_cl.failures()) { 823 *failures = true; 824 } 825 if (G1MaxVerifyFailures >= 0 && 826 vl_cl.n_failures() >= G1MaxVerifyFailures) { 827 return; 828 } 829 } 830 } else { 831 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj); 832 *failures = true; 833 return; 834 } 835 } 836 prev_p = p; 837 p += obj_size; 838 } 839 840 if (p != top()) { 841 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" " 842 "does not match top "PTR_FORMAT, p, top()); 843 *failures = true; 844 return; 845 } 846 847 HeapWord* the_end = end(); 848 assert(p == top(), "it should still hold"); 849 // Do some extra BOT consistency checking for addresses in the 850 // range [top, end). BOT look-ups in this range should yield 851 // top. No point in doing that if top == end (there's nothing there). 852 if (p < the_end) { 853 // Look up top 854 HeapWord* addr_1 = p; 855 HeapWord* b_start_1 = _offsets.block_start_const(addr_1); 856 if (b_start_1 != p) { 857 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" " 858 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 859 addr_1, b_start_1, p); 860 *failures = true; 861 return; 862 } 863 864 // Look up top + 1 865 HeapWord* addr_2 = p + 1; 866 if (addr_2 < the_end) { 867 HeapWord* b_start_2 = _offsets.block_start_const(addr_2); 868 if (b_start_2 != p) { 869 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" " 870 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 871 addr_2, b_start_2, p); 872 *failures = true; 873 return; 874 } 875 } 876 877 // Look up an address between top and end 878 size_t diff = pointer_delta(the_end, p) / 2; 879 HeapWord* addr_3 = p + diff; 880 if (addr_3 < the_end) { 881 HeapWord* b_start_3 = _offsets.block_start_const(addr_3); 882 if (b_start_3 != p) { 883 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" " 884 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 885 addr_3, b_start_3, p); 886 *failures = true; 887 return; 888 } 889 } 890 891 // Loook up end - 1 892 HeapWord* addr_4 = the_end - 1; 893 HeapWord* b_start_4 = _offsets.block_start_const(addr_4); 894 if (b_start_4 != p) { 895 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" " 896 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 897 addr_4, b_start_4, p); 898 *failures = true; 899 return; 900 } 901 } 902 903 if (is_humongous && object_num > 1) { 904 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous " 905 "but has "SIZE_FORMAT", objects", 906 bottom(), end(), object_num); 907 *failures = true; 908 return; 909 } 910 } 911 912 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 913 // away eventually. 914 915 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 916 // false ==> we'll do the clearing if there's clearing to be done. 917 ContiguousSpace::initialize(mr, false, mangle_space); 918 _offsets.zero_bottom_entry(); 919 _offsets.initialize_threshold(); 920 if (clear_space) clear(mangle_space); 921 } 922 923 void G1OffsetTableContigSpace::clear(bool mangle_space) { 924 ContiguousSpace::clear(mangle_space); 925 _offsets.zero_bottom_entry(); 926 _offsets.initialize_threshold(); 927 } 928 929 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 930 Space::set_bottom(new_bottom); 931 _offsets.set_bottom(new_bottom); 932 } 933 934 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) { 935 Space::set_end(new_end); 936 _offsets.resize(new_end - bottom()); 937 } 938 939 void G1OffsetTableContigSpace::print() const { 940 print_short(); 941 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 942 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 943 bottom(), top(), _offsets.threshold(), end()); 944 } 945 946 HeapWord* G1OffsetTableContigSpace::initialize_threshold() { 947 return _offsets.initialize_threshold(); 948 } 949 950 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start, 951 HeapWord* end) { 952 _offsets.alloc_block(start, end); 953 return _offsets.threshold(); 954 } 955 956 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const { 957 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 958 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" ); 959 if (_gc_time_stamp < g1h->get_gc_time_stamp()) 960 return top(); 961 else 962 return ContiguousSpace::saved_mark_word(); 963 } 964 965 void G1OffsetTableContigSpace::set_saved_mark() { 966 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 967 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 968 969 if (_gc_time_stamp < curr_gc_time_stamp) { 970 // The order of these is important, as another thread might be 971 // about to start scanning this region. If it does so after 972 // set_saved_mark and before _gc_time_stamp = ..., then the latter 973 // will be false, and it will pick up top() as the high water mark 974 // of region. If it does so after _gc_time_stamp = ..., then it 975 // will pick up the right saved_mark_word() as the high water mark 976 // of the region. Either way, the behaviour will be correct. 977 ContiguousSpace::set_saved_mark(); 978 OrderAccess::storestore(); 979 _gc_time_stamp = curr_gc_time_stamp; 980 // No need to do another barrier to flush the writes above. If 981 // this is called in parallel with other threads trying to 982 // allocate into the region, the caller should call this while 983 // holding a lock and when the lock is released the writes will be 984 // flushed. 985 } 986 } 987 988 G1OffsetTableContigSpace:: 989 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 990 MemRegion mr, bool is_zeroed) : 991 _offsets(sharedOffsetArray, mr), 992 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 993 _gc_time_stamp(0) 994 { 995 _offsets.set_space(this); 996 initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 997 }