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 int HeapRegion::GrainBytes = 0; 39 int HeapRegion::GrainWords = 0; 40 int 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 = (int) region_size; 353 354 guarantee(GrainWords == 0, "we should only set it once"); 355 GrainWords = GrainBytes >> LogHeapWordSize; 356 guarantee(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 _is_gc_alloc_region = false; 388 389 set_young_index_in_cset(-1); 390 uninstall_surv_rate_group(); 391 set_young_type(NotYoung); 392 reset_pre_dummy_top(); 393 394 if (!par) { 395 // If this is parallel, this will be done later. 396 HeapRegionRemSet* hrrs = rem_set(); 397 if (hrrs != NULL) hrrs->clear(); 398 _claimed = InitialClaimValue; 399 } 400 zero_marked_bytes(); 401 set_sort_index(-1); 402 403 _offsets.resize(HeapRegion::GrainWords); 404 init_top_at_mark_start(); 405 if (clear_space) clear(SpaceDecorator::Mangle); 406 } 407 408 void HeapRegion::par_clear() { 409 assert(used() == 0, "the region should have been already cleared"); 410 assert(capacity() == (size_t) HeapRegion::GrainBytes, 411 "should be back to normal"); 412 HeapRegionRemSet* hrrs = rem_set(); 413 hrrs->clear(); 414 CardTableModRefBS* ct_bs = 415 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set(); 416 ct_bs->clear(MemRegion(bottom(), end())); 417 } 418 419 // <PREDICTION> 420 void HeapRegion::calc_gc_efficiency() { 421 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 422 _gc_efficiency = (double) garbage_bytes() / 423 g1h->predict_region_elapsed_time_ms(this, false); 424 } 425 // </PREDICTION> 426 427 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) { 428 assert(!isHumongous(), "sanity / pre-condition"); 429 assert(end() == _orig_end, 430 "Should be normal before the humongous object allocation"); 431 assert(top() == bottom(), "should be empty"); 432 assert(bottom() <= new_top && new_top <= new_end, "pre-condition"); 433 434 _humongous_type = StartsHumongous; 435 _humongous_start_region = this; 436 437 set_end(new_end); 438 _offsets.set_for_starts_humongous(new_top); 439 } 440 441 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) { 442 assert(!isHumongous(), "sanity / pre-condition"); 443 assert(end() == _orig_end, 444 "Should be normal before the humongous object allocation"); 445 assert(top() == bottom(), "should be empty"); 446 assert(first_hr->startsHumongous(), "pre-condition"); 447 448 _humongous_type = ContinuesHumongous; 449 _humongous_start_region = first_hr; 450 } 451 452 void HeapRegion::set_notHumongous() { 453 assert(isHumongous(), "pre-condition"); 454 455 if (startsHumongous()) { 456 assert(top() <= end(), "pre-condition"); 457 set_end(_orig_end); 458 if (top() > end()) { 459 // at least one "continues humongous" region after it 460 set_top(end()); 461 } 462 } else { 463 // continues humongous 464 assert(end() == _orig_end, "sanity"); 465 } 466 467 assert(capacity() == (size_t) HeapRegion::GrainBytes, "pre-condition"); 468 _humongous_type = NotHumongous; 469 _humongous_start_region = NULL; 470 } 471 472 bool HeapRegion::claimHeapRegion(jint claimValue) { 473 jint current = _claimed; 474 if (current != claimValue) { 475 jint res = Atomic::cmpxchg(claimValue, &_claimed, current); 476 if (res == current) { 477 return true; 478 } 479 } 480 return false; 481 } 482 483 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) { 484 HeapWord* low = addr; 485 HeapWord* high = end(); 486 while (low < high) { 487 size_t diff = pointer_delta(high, low); 488 // Must add one below to bias toward the high amount. Otherwise, if 489 // "high" were at the desired value, and "low" were one less, we 490 // would not converge on "high". This is not symmetric, because 491 // we set "high" to a block start, which might be the right one, 492 // which we don't do for "low". 493 HeapWord* middle = low + (diff+1)/2; 494 if (middle == high) return high; 495 HeapWord* mid_bs = block_start_careful(middle); 496 if (mid_bs < addr) { 497 low = middle; 498 } else { 499 high = mid_bs; 500 } 501 } 502 assert(low == high && low >= addr, "Didn't work."); 503 return low; 504 } 505 506 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 507 G1OffsetTableContigSpace::initialize(mr, false, mangle_space); 508 hr_clear(false/*par*/, clear_space); 509 } 510 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away 511 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 512 #endif // _MSC_VER 513 514 515 HeapRegion:: 516 HeapRegion(size_t hrs_index, G1BlockOffsetSharedArray* sharedOffsetArray, 517 MemRegion mr, bool is_zeroed) 518 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed), 519 _hrs_index(hrs_index), 520 _humongous_type(NotHumongous), _humongous_start_region(NULL), 521 _in_collection_set(false), _is_gc_alloc_region(false), 522 _next_in_special_set(NULL), _orig_end(NULL), 523 _claimed(InitialClaimValue), _evacuation_failed(false), 524 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1), 525 _young_type(NotYoung), _next_young_region(NULL), 526 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false), 527 #ifdef ASSERT 528 _containing_set(NULL), 529 #endif // ASSERT 530 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 531 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 532 _predicted_bytes_to_copy(0) 533 { 534 _orig_end = mr.end(); 535 // Note that initialize() will set the start of the unmarked area of the 536 // region. 537 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 538 set_top(bottom()); 539 set_saved_mark(); 540 541 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this); 542 543 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant."); 544 // In case the region is allocated during a pause, note the top. 545 // We haven't done any counting on a brand new region. 546 _top_at_conc_mark_count = bottom(); 547 } 548 549 class NextCompactionHeapRegionClosure: public HeapRegionClosure { 550 const HeapRegion* _target; 551 bool _target_seen; 552 HeapRegion* _last; 553 CompactibleSpace* _res; 554 public: 555 NextCompactionHeapRegionClosure(const HeapRegion* target) : 556 _target(target), _target_seen(false), _res(NULL) {} 557 bool doHeapRegion(HeapRegion* cur) { 558 if (_target_seen) { 559 if (!cur->isHumongous()) { 560 _res = cur; 561 return true; 562 } 563 } else if (cur == _target) { 564 _target_seen = true; 565 } 566 return false; 567 } 568 CompactibleSpace* result() { return _res; } 569 }; 570 571 CompactibleSpace* HeapRegion::next_compaction_space() const { 572 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 573 // cast away const-ness 574 HeapRegion* r = (HeapRegion*) this; 575 NextCompactionHeapRegionClosure blk(r); 576 g1h->heap_region_iterate_from(r, &blk); 577 return blk.result(); 578 } 579 580 void HeapRegion::save_marks() { 581 set_saved_mark(); 582 } 583 584 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) { 585 HeapWord* p = mr.start(); 586 HeapWord* e = mr.end(); 587 oop obj; 588 while (p < e) { 589 obj = oop(p); 590 p += obj->oop_iterate(cl); 591 } 592 assert(p == e, "bad memregion: doesn't end on obj boundary"); 593 } 594 595 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ 596 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ 597 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \ 598 } 599 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN) 600 601 602 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) { 603 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl); 604 } 605 606 HeapWord* 607 HeapRegion::object_iterate_mem_careful(MemRegion mr, 608 ObjectClosure* cl) { 609 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 610 // We used to use "block_start_careful" here. But we're actually happy 611 // to update the BOT while we do this... 612 HeapWord* cur = block_start(mr.start()); 613 mr = mr.intersection(used_region()); 614 if (mr.is_empty()) return NULL; 615 // Otherwise, find the obj that extends onto mr.start(). 616 617 assert(cur <= mr.start() 618 && (oop(cur)->klass_or_null() == NULL || 619 cur + oop(cur)->size() > mr.start()), 620 "postcondition of block_start"); 621 oop obj; 622 while (cur < mr.end()) { 623 obj = oop(cur); 624 if (obj->klass_or_null() == NULL) { 625 // Ran into an unparseable point. 626 return cur; 627 } else if (!g1h->is_obj_dead(obj)) { 628 cl->do_object(obj); 629 } 630 if (cl->abort()) return cur; 631 // The check above must occur before the operation below, since an 632 // abort might invalidate the "size" operation. 633 cur += obj->size(); 634 } 635 return NULL; 636 } 637 638 HeapWord* 639 HeapRegion:: 640 oops_on_card_seq_iterate_careful(MemRegion mr, 641 FilterOutOfRegionClosure* cl, 642 bool filter_young, 643 jbyte* card_ptr) { 644 // Currently, we should only have to clean the card if filter_young 645 // is true and vice versa. 646 if (filter_young) { 647 assert(card_ptr != NULL, "pre-condition"); 648 } else { 649 assert(card_ptr == NULL, "pre-condition"); 650 } 651 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 652 653 // If we're within a stop-world GC, then we might look at a card in a 654 // GC alloc region that extends onto a GC LAB, which may not be 655 // parseable. Stop such at the "saved_mark" of the region. 656 if (G1CollectedHeap::heap()->is_gc_active()) { 657 mr = mr.intersection(used_region_at_save_marks()); 658 } else { 659 mr = mr.intersection(used_region()); 660 } 661 if (mr.is_empty()) return NULL; 662 // Otherwise, find the obj that extends onto mr.start(). 663 664 // The intersection of the incoming mr (for the card) and the 665 // allocated part of the region is non-empty. This implies that 666 // we have actually allocated into this region. The code in 667 // G1CollectedHeap.cpp that allocates a new region sets the 668 // is_young tag on the region before allocating. Thus we 669 // safely know if this region is young. 670 if (is_young() && filter_young) { 671 return NULL; 672 } 673 674 assert(!is_young(), "check value of filter_young"); 675 676 // We can only clean the card here, after we make the decision that 677 // the card is not young. And we only clean the card if we have been 678 // asked to (i.e., card_ptr != NULL). 679 if (card_ptr != NULL) { 680 *card_ptr = CardTableModRefBS::clean_card_val(); 681 // We must complete this write before we do any of the reads below. 682 OrderAccess::storeload(); 683 } 684 685 // We used to use "block_start_careful" here. But we're actually happy 686 // to update the BOT while we do this... 687 HeapWord* cur = block_start(mr.start()); 688 assert(cur <= mr.start(), "Postcondition"); 689 690 while (cur <= mr.start()) { 691 if (oop(cur)->klass_or_null() == NULL) { 692 // Ran into an unparseable point. 693 return cur; 694 } 695 // Otherwise... 696 int sz = oop(cur)->size(); 697 if (cur + sz > mr.start()) break; 698 // Otherwise, go on. 699 cur = cur + sz; 700 } 701 oop obj; 702 obj = oop(cur); 703 // If we finish this loop... 704 assert(cur <= mr.start() 705 && obj->klass_or_null() != NULL 706 && cur + obj->size() > mr.start(), 707 "Loop postcondition"); 708 if (!g1h->is_obj_dead(obj)) { 709 obj->oop_iterate(cl, mr); 710 } 711 712 HeapWord* next; 713 while (cur < mr.end()) { 714 obj = oop(cur); 715 if (obj->klass_or_null() == NULL) { 716 // Ran into an unparseable point. 717 return cur; 718 }; 719 // Otherwise: 720 next = (cur + obj->size()); 721 if (!g1h->is_obj_dead(obj)) { 722 if (next < mr.end()) { 723 obj->oop_iterate(cl); 724 } else { 725 // this obj spans the boundary. If it's an array, stop at the 726 // boundary. 727 if (obj->is_objArray()) { 728 obj->oop_iterate(cl, mr); 729 } else { 730 obj->oop_iterate(cl); 731 } 732 } 733 } 734 cur = next; 735 } 736 return NULL; 737 } 738 739 void HeapRegion::print() const { print_on(gclog_or_tty); } 740 void HeapRegion::print_on(outputStream* st) const { 741 if (isHumongous()) { 742 if (startsHumongous()) 743 st->print(" HS"); 744 else 745 st->print(" HC"); 746 } else { 747 st->print(" "); 748 } 749 if (in_collection_set()) 750 st->print(" CS"); 751 else if (is_gc_alloc_region()) 752 st->print(" A "); 753 else 754 st->print(" "); 755 if (is_young()) 756 st->print(is_survivor() ? " SU" : " Y "); 757 else 758 st->print(" "); 759 if (is_empty()) 760 st->print(" F"); 761 else 762 st->print(" "); 763 st->print(" %5d", _gc_time_stamp); 764 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT, 765 prev_top_at_mark_start(), next_top_at_mark_start()); 766 G1OffsetTableContigSpace::print_on(st); 767 } 768 769 void HeapRegion::verify(bool allow_dirty) const { 770 bool dummy = false; 771 verify(allow_dirty, VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 772 } 773 774 // This really ought to be commoned up into OffsetTableContigSpace somehow. 775 // We would need a mechanism to make that code skip dead objects. 776 777 void HeapRegion::verify(bool allow_dirty, 778 VerifyOption vo, 779 bool* failures) const { 780 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 781 *failures = false; 782 HeapWord* p = bottom(); 783 HeapWord* prev_p = NULL; 784 VerifyLiveClosure vl_cl(g1, vo); 785 bool is_humongous = isHumongous(); 786 bool do_bot_verify = !is_young(); 787 size_t object_num = 0; 788 while (p < top()) { 789 oop obj = oop(p); 790 size_t obj_size = obj->size(); 791 object_num += 1; 792 793 if (is_humongous != g1->isHumongous(obj_size)) { 794 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size (" 795 SIZE_FORMAT" words) in a %shumongous region", 796 p, g1->isHumongous(obj_size) ? "" : "non-", 797 obj_size, is_humongous ? "" : "non-"); 798 *failures = true; 799 return; 800 } 801 802 // If it returns false, verify_for_object() will output the 803 // appropriate messasge. 804 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) { 805 *failures = true; 806 return; 807 } 808 809 if (!g1->is_obj_dead_cond(obj, this, vo)) { 810 if (obj->is_oop()) { 811 klassOop klass = obj->klass(); 812 if (!klass->is_perm()) { 813 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 814 "not in perm", klass, obj); 815 *failures = true; 816 return; 817 } else if (!klass->is_klass()) { 818 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 819 "not a klass", klass, obj); 820 *failures = true; 821 return; 822 } else { 823 vl_cl.set_containing_obj(obj); 824 obj->oop_iterate(&vl_cl); 825 if (vl_cl.failures()) { 826 *failures = true; 827 } 828 if (G1MaxVerifyFailures >= 0 && 829 vl_cl.n_failures() >= G1MaxVerifyFailures) { 830 return; 831 } 832 } 833 } else { 834 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj); 835 *failures = true; 836 return; 837 } 838 } 839 prev_p = p; 840 p += obj_size; 841 } 842 843 if (p != top()) { 844 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" " 845 "does not match top "PTR_FORMAT, p, top()); 846 *failures = true; 847 return; 848 } 849 850 HeapWord* the_end = end(); 851 assert(p == top(), "it should still hold"); 852 // Do some extra BOT consistency checking for addresses in the 853 // range [top, end). BOT look-ups in this range should yield 854 // top. No point in doing that if top == end (there's nothing there). 855 if (p < the_end) { 856 // Look up top 857 HeapWord* addr_1 = p; 858 HeapWord* b_start_1 = _offsets.block_start_const(addr_1); 859 if (b_start_1 != p) { 860 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" " 861 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 862 addr_1, b_start_1, p); 863 *failures = true; 864 return; 865 } 866 867 // Look up top + 1 868 HeapWord* addr_2 = p + 1; 869 if (addr_2 < the_end) { 870 HeapWord* b_start_2 = _offsets.block_start_const(addr_2); 871 if (b_start_2 != p) { 872 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" " 873 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 874 addr_2, b_start_2, p); 875 *failures = true; 876 return; 877 } 878 } 879 880 // Look up an address between top and end 881 size_t diff = pointer_delta(the_end, p) / 2; 882 HeapWord* addr_3 = p + diff; 883 if (addr_3 < the_end) { 884 HeapWord* b_start_3 = _offsets.block_start_const(addr_3); 885 if (b_start_3 != p) { 886 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" " 887 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 888 addr_3, b_start_3, p); 889 *failures = true; 890 return; 891 } 892 } 893 894 // Loook up end - 1 895 HeapWord* addr_4 = the_end - 1; 896 HeapWord* b_start_4 = _offsets.block_start_const(addr_4); 897 if (b_start_4 != p) { 898 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" " 899 " yielded "PTR_FORMAT", expecting "PTR_FORMAT, 900 addr_4, b_start_4, p); 901 *failures = true; 902 return; 903 } 904 } 905 906 if (is_humongous && object_num > 1) { 907 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous " 908 "but has "SIZE_FORMAT", objects", 909 bottom(), end(), object_num); 910 *failures = true; 911 return; 912 } 913 } 914 915 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 916 // away eventually. 917 918 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 919 // false ==> we'll do the clearing if there's clearing to be done. 920 ContiguousSpace::initialize(mr, false, mangle_space); 921 _offsets.zero_bottom_entry(); 922 _offsets.initialize_threshold(); 923 if (clear_space) clear(mangle_space); 924 } 925 926 void G1OffsetTableContigSpace::clear(bool mangle_space) { 927 ContiguousSpace::clear(mangle_space); 928 _offsets.zero_bottom_entry(); 929 _offsets.initialize_threshold(); 930 } 931 932 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 933 Space::set_bottom(new_bottom); 934 _offsets.set_bottom(new_bottom); 935 } 936 937 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) { 938 Space::set_end(new_end); 939 _offsets.resize(new_end - bottom()); 940 } 941 942 void G1OffsetTableContigSpace::print() const { 943 print_short(); 944 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 945 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 946 bottom(), top(), _offsets.threshold(), end()); 947 } 948 949 HeapWord* G1OffsetTableContigSpace::initialize_threshold() { 950 return _offsets.initialize_threshold(); 951 } 952 953 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start, 954 HeapWord* end) { 955 _offsets.alloc_block(start, end); 956 return _offsets.threshold(); 957 } 958 959 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const { 960 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 961 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" ); 962 if (_gc_time_stamp < g1h->get_gc_time_stamp()) 963 return top(); 964 else 965 return ContiguousSpace::saved_mark_word(); 966 } 967 968 void G1OffsetTableContigSpace::set_saved_mark() { 969 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 970 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 971 972 if (_gc_time_stamp < curr_gc_time_stamp) { 973 // The order of these is important, as another thread might be 974 // about to start scanning this region. If it does so after 975 // set_saved_mark and before _gc_time_stamp = ..., then the latter 976 // will be false, and it will pick up top() as the high water mark 977 // of region. If it does so after _gc_time_stamp = ..., then it 978 // will pick up the right saved_mark_word() as the high water mark 979 // of the region. Either way, the behaviour will be correct. 980 ContiguousSpace::set_saved_mark(); 981 OrderAccess::storestore(); 982 _gc_time_stamp = curr_gc_time_stamp; 983 // No need to do another barrier to flush the writes above. If 984 // this is called in parallel with other threads trying to 985 // allocate into the region, the caller should call this while 986 // holding a lock and when the lock is released the writes will be 987 // flushed. 988 } 989 } 990 991 G1OffsetTableContigSpace:: 992 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 993 MemRegion mr, bool is_zeroed) : 994 _offsets(sharedOffsetArray, mr), 995 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 996 _gc_time_stamp(0) 997 { 998 _offsets.set_space(this); 999 initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 1000 }