1 /* 2 * Copyright (c) 2001, 2010, 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 "incls/_precompiled.incl" 26 #include "incls/_heapRegion.cpp.incl" 27 28 int HeapRegion::LogOfHRGrainBytes = 0; 29 int HeapRegion::LogOfHRGrainWords = 0; 30 int HeapRegion::GrainBytes = 0; 31 int HeapRegion::GrainWords = 0; 32 int HeapRegion::CardsPerRegion = 0; 33 34 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1, 35 HeapRegion* hr, OopClosure* cl, 36 CardTableModRefBS::PrecisionStyle precision, 37 FilterKind fk) : 38 ContiguousSpaceDCTOC(hr, cl, precision, NULL), 39 _hr(hr), _fk(fk), _g1(g1) 40 {} 41 42 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 43 OopClosure* oc) : 44 _r_bottom(r->bottom()), _r_end(r->end()), 45 _oc(oc), _out_of_region(0) 46 {} 47 48 class VerifyLiveClosure: public OopClosure { 49 private: 50 G1CollectedHeap* _g1h; 51 CardTableModRefBS* _bs; 52 oop _containing_obj; 53 bool _failures; 54 int _n_failures; 55 bool _use_prev_marking; 56 public: 57 // use_prev_marking == true -> use "prev" marking information, 58 // use_prev_marking == false -> use "next" marking information 59 VerifyLiveClosure(G1CollectedHeap* g1h, bool use_prev_marking) : 60 _g1h(g1h), _bs(NULL), _containing_obj(NULL), 61 _failures(false), _n_failures(0), _use_prev_marking(use_prev_marking) 62 { 63 BarrierSet* bs = _g1h->barrier_set(); 64 if (bs->is_a(BarrierSet::CardTableModRef)) 65 _bs = (CardTableModRefBS*)bs; 66 } 67 68 void set_containing_obj(oop obj) { 69 _containing_obj = obj; 70 } 71 72 bool failures() { return _failures; } 73 int n_failures() { return _n_failures; } 74 75 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 76 virtual void do_oop( oop* p) { do_oop_work(p); } 77 78 void print_object(outputStream* out, oop obj) { 79 #ifdef PRODUCT 80 klassOop k = obj->klass(); 81 const char* class_name = instanceKlass::cast(k)->external_name(); 82 out->print_cr("class name %s", class_name); 83 #else // PRODUCT 84 obj->print_on(out); 85 #endif // PRODUCT 86 } 87 88 template <class T> void do_oop_work(T* p) { 89 assert(_containing_obj != NULL, "Precondition"); 90 assert(!_g1h->is_obj_dead_cond(_containing_obj, _use_prev_marking), 91 "Precondition"); 92 T heap_oop = oopDesc::load_heap_oop(p); 93 if (!oopDesc::is_null(heap_oop)) { 94 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 95 bool failed = false; 96 if (!_g1h->is_in_closed_subset(obj) || 97 _g1h->is_obj_dead_cond(obj, _use_prev_marking)) { 98 if (!_failures) { 99 gclog_or_tty->print_cr(""); 100 gclog_or_tty->print_cr("----------"); 101 } 102 if (!_g1h->is_in_closed_subset(obj)) { 103 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 104 gclog_or_tty->print_cr("Field "PTR_FORMAT 105 " of live obj "PTR_FORMAT" in region " 106 "["PTR_FORMAT", "PTR_FORMAT")", 107 p, (void*) _containing_obj, 108 from->bottom(), from->end()); 109 print_object(gclog_or_tty, _containing_obj); 110 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap", 111 (void*) obj); 112 } else { 113 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 114 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 115 gclog_or_tty->print_cr("Field "PTR_FORMAT 116 " of live obj "PTR_FORMAT" in region " 117 "["PTR_FORMAT", "PTR_FORMAT")", 118 p, (void*) _containing_obj, 119 from->bottom(), from->end()); 120 print_object(gclog_or_tty, _containing_obj); 121 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region " 122 "["PTR_FORMAT", "PTR_FORMAT")", 123 (void*) obj, to->bottom(), to->end()); 124 print_object(gclog_or_tty, obj); 125 } 126 gclog_or_tty->print_cr("----------"); 127 _failures = true; 128 failed = true; 129 _n_failures++; 130 } 131 132 if (!_g1h->full_collection()) { 133 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 134 HeapRegion* to = _g1h->heap_region_containing(obj); 135 if (from != NULL && to != NULL && 136 from != to && 137 !to->isHumongous()) { 138 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 139 jbyte cv_field = *_bs->byte_for_const(p); 140 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 141 142 bool is_bad = !(from->is_young() 143 || to->rem_set()->contains_reference(p) 144 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 145 (_containing_obj->is_objArray() ? 146 cv_field == dirty 147 : cv_obj == dirty || cv_field == dirty)); 148 if (is_bad) { 149 if (!_failures) { 150 gclog_or_tty->print_cr(""); 151 gclog_or_tty->print_cr("----------"); 152 } 153 gclog_or_tty->print_cr("Missing rem set entry:"); 154 gclog_or_tty->print_cr("Field "PTR_FORMAT 155 " of obj "PTR_FORMAT 156 ", in region %d ["PTR_FORMAT 157 ", "PTR_FORMAT"),", 158 p, (void*) _containing_obj, 159 from->hrs_index(), 160 from->bottom(), 161 from->end()); 162 _containing_obj->print_on(gclog_or_tty); 163 gclog_or_tty->print_cr("points to obj "PTR_FORMAT 164 " in region %d ["PTR_FORMAT 165 ", "PTR_FORMAT").", 166 (void*) obj, to->hrs_index(), 167 to->bottom(), to->end()); 168 obj->print_on(gclog_or_tty); 169 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.", 170 cv_obj, cv_field); 171 gclog_or_tty->print_cr("----------"); 172 _failures = true; 173 if (!failed) _n_failures++; 174 } 175 } 176 } 177 } 178 } 179 }; 180 181 template<class ClosureType> 182 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h, 183 HeapRegion* hr, 184 HeapWord* cur, HeapWord* top) { 185 oop cur_oop = oop(cur); 186 int oop_size = cur_oop->size(); 187 HeapWord* next_obj = cur + oop_size; 188 while (next_obj < top) { 189 // Keep filtering the remembered set. 190 if (!g1h->is_obj_dead(cur_oop, hr)) { 191 // Bottom lies entirely below top, so we can call the 192 // non-memRegion version of oop_iterate below. 193 cur_oop->oop_iterate(cl); 194 } 195 cur = next_obj; 196 cur_oop = oop(cur); 197 oop_size = cur_oop->size(); 198 next_obj = cur + oop_size; 199 } 200 return cur; 201 } 202 203 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr, 204 HeapWord* bottom, 205 HeapWord* top, 206 OopClosure* cl) { 207 G1CollectedHeap* g1h = _g1; 208 209 int oop_size; 210 211 OopClosure* cl2 = cl; 212 FilterIntoCSClosure intoCSFilt(this, g1h, cl); 213 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl); 214 switch (_fk) { 215 case IntoCSFilterKind: cl2 = &intoCSFilt; break; 216 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break; 217 } 218 219 // Start filtering what we add to the remembered set. If the object is 220 // not considered dead, either because it is marked (in the mark bitmap) 221 // or it was allocated after marking finished, then we add it. Otherwise 222 // we can safely ignore the object. 223 if (!g1h->is_obj_dead(oop(bottom), _hr)) { 224 oop_size = oop(bottom)->oop_iterate(cl2, mr); 225 } else { 226 oop_size = oop(bottom)->size(); 227 } 228 229 bottom += oop_size; 230 231 if (bottom < top) { 232 // We replicate the loop below for several kinds of possible filters. 233 switch (_fk) { 234 case NoFilterKind: 235 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top); 236 break; 237 case IntoCSFilterKind: { 238 FilterIntoCSClosure filt(this, g1h, cl); 239 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top); 240 break; 241 } 242 case OutOfRegionFilterKind: { 243 FilterOutOfRegionClosure filt(_hr, cl); 244 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top); 245 break; 246 } 247 default: 248 ShouldNotReachHere(); 249 } 250 251 // Last object. Need to do dead-obj filtering here too. 252 if (!g1h->is_obj_dead(oop(bottom), _hr)) { 253 oop(bottom)->oop_iterate(cl2, mr); 254 } 255 } 256 } 257 258 // Minimum region size; we won't go lower than that. 259 // We might want to decrease this in the future, to deal with small 260 // heaps a bit more efficiently. 261 #define MIN_REGION_SIZE ( 1024 * 1024 ) 262 263 // Maximum region size; we don't go higher than that. There's a good 264 // reason for having an upper bound. We don't want regions to get too 265 // large, otherwise cleanup's effectiveness would decrease as there 266 // will be fewer opportunities to find totally empty regions after 267 // marking. 268 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 ) 269 270 // The automatic region size calculation will try to have around this 271 // many regions in the heap (based on the min heap size). 272 #define TARGET_REGION_NUMBER 2048 273 274 void HeapRegion::setup_heap_region_size(uintx min_heap_size) { 275 // region_size in bytes 276 uintx region_size = G1HeapRegionSize; 277 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 278 // We base the automatic calculation on the min heap size. This 279 // can be problematic if the spread between min and max is quite 280 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on 281 // the max size, the region size might be way too large for the 282 // min size. Either way, some users might have to set the region 283 // size manually for some -Xms / -Xmx combos. 284 285 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER, 286 (uintx) MIN_REGION_SIZE); 287 } 288 289 int region_size_log = log2_long((jlong) region_size); 290 // Recalculate the region size to make sure it's a power of 291 // 2. This means that region_size is the largest power of 2 that's 292 // <= what we've calculated so far. 293 region_size = ((uintx)1 << region_size_log); 294 295 // Now make sure that we don't go over or under our limits. 296 if (region_size < MIN_REGION_SIZE) { 297 region_size = MIN_REGION_SIZE; 298 } else if (region_size > MAX_REGION_SIZE) { 299 region_size = MAX_REGION_SIZE; 300 } 301 302 // And recalculate the log. 303 region_size_log = log2_long((jlong) region_size); 304 305 // Now, set up the globals. 306 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 307 LogOfHRGrainBytes = region_size_log; 308 309 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 310 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 311 312 guarantee(GrainBytes == 0, "we should only set it once"); 313 // The cast to int is safe, given that we've bounded region_size by 314 // MIN_REGION_SIZE and MAX_REGION_SIZE. 315 GrainBytes = (int) region_size; 316 317 guarantee(GrainWords == 0, "we should only set it once"); 318 GrainWords = GrainBytes >> LogHeapWordSize; 319 guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity"); 320 321 guarantee(CardsPerRegion == 0, "we should only set it once"); 322 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; 323 } 324 325 void HeapRegion::reset_after_compaction() { 326 G1OffsetTableContigSpace::reset_after_compaction(); 327 // After a compaction the mark bitmap is invalid, so we must 328 // treat all objects as being inside the unmarked area. 329 zero_marked_bytes(); 330 init_top_at_mark_start(); 331 } 332 333 DirtyCardToOopClosure* 334 HeapRegion::new_dcto_closure(OopClosure* cl, 335 CardTableModRefBS::PrecisionStyle precision, 336 HeapRegionDCTOC::FilterKind fk) { 337 return new HeapRegionDCTOC(G1CollectedHeap::heap(), 338 this, cl, precision, fk); 339 } 340 341 void HeapRegion::hr_clear(bool par, bool clear_space) { 342 _humongous_type = NotHumongous; 343 _humongous_start_region = NULL; 344 _in_collection_set = false; 345 _is_gc_alloc_region = false; 346 347 // Age stuff (if parallel, this will be done separately, since it needs 348 // to be sequential). 349 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 350 351 set_young_index_in_cset(-1); 352 uninstall_surv_rate_group(); 353 set_young_type(NotYoung); 354 355 // In case it had been the start of a humongous sequence, reset its end. 356 set_end(_orig_end); 357 358 if (!par) { 359 // If this is parallel, this will be done later. 360 HeapRegionRemSet* hrrs = rem_set(); 361 if (hrrs != NULL) hrrs->clear(); 362 _claimed = InitialClaimValue; 363 } 364 zero_marked_bytes(); 365 set_sort_index(-1); 366 367 _offsets.resize(HeapRegion::GrainWords); 368 init_top_at_mark_start(); 369 if (clear_space) clear(SpaceDecorator::Mangle); 370 } 371 372 // <PREDICTION> 373 void HeapRegion::calc_gc_efficiency() { 374 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 375 _gc_efficiency = (double) garbage_bytes() / 376 g1h->predict_region_elapsed_time_ms(this, false); 377 } 378 // </PREDICTION> 379 380 void HeapRegion::set_startsHumongous() { 381 _humongous_type = StartsHumongous; 382 _humongous_start_region = this; 383 assert(end() == _orig_end, "Should be normal before alloc."); 384 } 385 386 bool HeapRegion::claimHeapRegion(jint claimValue) { 387 jint current = _claimed; 388 if (current != claimValue) { 389 jint res = Atomic::cmpxchg(claimValue, &_claimed, current); 390 if (res == current) { 391 return true; 392 } 393 } 394 return false; 395 } 396 397 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) { 398 HeapWord* low = addr; 399 HeapWord* high = end(); 400 while (low < high) { 401 size_t diff = pointer_delta(high, low); 402 // Must add one below to bias toward the high amount. Otherwise, if 403 // "high" were at the desired value, and "low" were one less, we 404 // would not converge on "high". This is not symmetric, because 405 // we set "high" to a block start, which might be the right one, 406 // which we don't do for "low". 407 HeapWord* middle = low + (diff+1)/2; 408 if (middle == high) return high; 409 HeapWord* mid_bs = block_start_careful(middle); 410 if (mid_bs < addr) { 411 low = middle; 412 } else { 413 high = mid_bs; 414 } 415 } 416 assert(low == high && low >= addr, "Didn't work."); 417 return low; 418 } 419 420 void HeapRegion::set_next_on_unclean_list(HeapRegion* r) { 421 assert(r == NULL || r->is_on_unclean_list(), "Malformed unclean list."); 422 _next_in_special_set = r; 423 } 424 425 void HeapRegion::set_on_unclean_list(bool b) { 426 _is_on_unclean_list = b; 427 } 428 429 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 430 G1OffsetTableContigSpace::initialize(mr, false, mangle_space); 431 hr_clear(false/*par*/, clear_space); 432 } 433 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away 434 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 435 #endif // _MSC_VER 436 437 438 HeapRegion:: 439 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray, 440 MemRegion mr, bool is_zeroed) 441 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed), 442 _next_fk(HeapRegionDCTOC::NoFilterKind), 443 _hrs_index(-1), 444 _humongous_type(NotHumongous), _humongous_start_region(NULL), 445 _in_collection_set(false), _is_gc_alloc_region(false), 446 _is_on_free_list(false), _is_on_unclean_list(false), 447 _next_in_special_set(NULL), _orig_end(NULL), 448 _claimed(InitialClaimValue), _evacuation_failed(false), 449 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1), 450 _young_type(NotYoung), _next_young_region(NULL), 451 _next_dirty_cards_region(NULL), 452 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 453 _rem_set(NULL), _zfs(NotZeroFilled), 454 _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 455 _predicted_bytes_to_copy(0) 456 { 457 _orig_end = mr.end(); 458 // Note that initialize() will set the start of the unmarked area of the 459 // region. 460 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 461 set_top(bottom()); 462 set_saved_mark(); 463 464 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this); 465 466 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant."); 467 // In case the region is allocated during a pause, note the top. 468 // We haven't done any counting on a brand new region. 469 _top_at_conc_mark_count = bottom(); 470 } 471 472 class NextCompactionHeapRegionClosure: public HeapRegionClosure { 473 const HeapRegion* _target; 474 bool _target_seen; 475 HeapRegion* _last; 476 CompactibleSpace* _res; 477 public: 478 NextCompactionHeapRegionClosure(const HeapRegion* target) : 479 _target(target), _target_seen(false), _res(NULL) {} 480 bool doHeapRegion(HeapRegion* cur) { 481 if (_target_seen) { 482 if (!cur->isHumongous()) { 483 _res = cur; 484 return true; 485 } 486 } else if (cur == _target) { 487 _target_seen = true; 488 } 489 return false; 490 } 491 CompactibleSpace* result() { return _res; } 492 }; 493 494 CompactibleSpace* HeapRegion::next_compaction_space() const { 495 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 496 // cast away const-ness 497 HeapRegion* r = (HeapRegion*) this; 498 NextCompactionHeapRegionClosure blk(r); 499 g1h->heap_region_iterate_from(r, &blk); 500 return blk.result(); 501 } 502 503 void HeapRegion::set_continuesHumongous(HeapRegion* start) { 504 // The order is important here. 505 start->add_continuingHumongousRegion(this); 506 _humongous_type = ContinuesHumongous; 507 _humongous_start_region = start; 508 } 509 510 void HeapRegion::add_continuingHumongousRegion(HeapRegion* cont) { 511 // Must join the blocks of the current H region seq with the block of the 512 // added region. 513 offsets()->join_blocks(bottom(), cont->bottom()); 514 arrayOop obj = (arrayOop)(bottom()); 515 obj->set_length((int) (obj->length() + cont->capacity()/jintSize)); 516 set_end(cont->end()); 517 set_top(cont->end()); 518 } 519 520 void HeapRegion::save_marks() { 521 set_saved_mark(); 522 } 523 524 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) { 525 HeapWord* p = mr.start(); 526 HeapWord* e = mr.end(); 527 oop obj; 528 while (p < e) { 529 obj = oop(p); 530 p += obj->oop_iterate(cl); 531 } 532 assert(p == e, "bad memregion: doesn't end on obj boundary"); 533 } 534 535 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ 536 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ 537 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \ 538 } 539 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN) 540 541 542 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) { 543 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl); 544 } 545 546 #ifdef DEBUG 547 HeapWord* HeapRegion::allocate(size_t size) { 548 jint state = zero_fill_state(); 549 assert(!G1CollectedHeap::heap()->allocs_are_zero_filled() || 550 zero_fill_is_allocated(), 551 "When ZF is on, only alloc in ZF'd regions"); 552 return G1OffsetTableContigSpace::allocate(size); 553 } 554 #endif 555 556 void HeapRegion::set_zero_fill_state_work(ZeroFillState zfs) { 557 assert(ZF_mon->owned_by_self() || 558 Universe::heap()->is_gc_active(), 559 "Must hold the lock or be a full GC to modify."); 560 #ifdef ASSERT 561 if (top() != bottom() && zfs != Allocated) { 562 ResourceMark rm; 563 stringStream region_str; 564 print_on(®ion_str); 565 assert(top() == bottom() || zfs == Allocated, 566 err_msg("Region must be empty, or we must be setting it to allocated. " 567 "_zfs=%d, zfs=%d, region: %s", _zfs, zfs, region_str.as_string())); 568 } 569 #endif 570 _zfs = zfs; 571 } 572 573 void HeapRegion::set_zero_fill_complete() { 574 set_zero_fill_state_work(ZeroFilled); 575 if (ZF_mon->owned_by_self()) { 576 ZF_mon->notify_all(); 577 } 578 } 579 580 581 void HeapRegion::ensure_zero_filled() { 582 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag); 583 ensure_zero_filled_locked(); 584 } 585 586 void HeapRegion::ensure_zero_filled_locked() { 587 assert(ZF_mon->owned_by_self(), "Precondition"); 588 bool should_ignore_zf = SafepointSynchronize::is_at_safepoint(); 589 assert(should_ignore_zf || Heap_lock->is_locked(), 590 "Either we're in a GC or we're allocating a region."); 591 switch (zero_fill_state()) { 592 case HeapRegion::NotZeroFilled: 593 set_zero_fill_in_progress(Thread::current()); 594 { 595 ZF_mon->unlock(); 596 Copy::fill_to_words(bottom(), capacity()/HeapWordSize); 597 ZF_mon->lock_without_safepoint_check(); 598 } 599 // A trap. 600 guarantee(zero_fill_state() == HeapRegion::ZeroFilling 601 && zero_filler() == Thread::current(), 602 "AHA! Tell Dave D if you see this..."); 603 set_zero_fill_complete(); 604 // gclog_or_tty->print_cr("Did sync ZF."); 605 ConcurrentZFThread::note_sync_zfs(); 606 break; 607 case HeapRegion::ZeroFilling: 608 if (should_ignore_zf) { 609 // We can "break" the lock and take over the work. 610 Copy::fill_to_words(bottom(), capacity()/HeapWordSize); 611 set_zero_fill_complete(); 612 ConcurrentZFThread::note_sync_zfs(); 613 break; 614 } else { 615 ConcurrentZFThread::wait_for_ZF_completed(this); 616 } 617 case HeapRegion::ZeroFilled: 618 // Nothing to do. 619 break; 620 case HeapRegion::Allocated: 621 guarantee(false, "Should not call on allocated regions."); 622 } 623 assert(zero_fill_state() == HeapRegion::ZeroFilled, "Post"); 624 } 625 626 HeapWord* 627 HeapRegion::object_iterate_mem_careful(MemRegion mr, 628 ObjectClosure* cl) { 629 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 630 // We used to use "block_start_careful" here. But we're actually happy 631 // to update the BOT while we do this... 632 HeapWord* cur = block_start(mr.start()); 633 mr = mr.intersection(used_region()); 634 if (mr.is_empty()) return NULL; 635 // Otherwise, find the obj that extends onto mr.start(). 636 637 assert(cur <= mr.start() 638 && (oop(cur)->klass_or_null() == NULL || 639 cur + oop(cur)->size() > mr.start()), 640 "postcondition of block_start"); 641 oop obj; 642 while (cur < mr.end()) { 643 obj = oop(cur); 644 if (obj->klass_or_null() == NULL) { 645 // Ran into an unparseable point. 646 return cur; 647 } else if (!g1h->is_obj_dead(obj)) { 648 cl->do_object(obj); 649 } 650 if (cl->abort()) return cur; 651 // The check above must occur before the operation below, since an 652 // abort might invalidate the "size" operation. 653 cur += obj->size(); 654 } 655 return NULL; 656 } 657 658 HeapWord* 659 HeapRegion:: 660 oops_on_card_seq_iterate_careful(MemRegion mr, 661 FilterOutOfRegionClosure* cl, 662 bool filter_young) { 663 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 664 665 // If we're within a stop-world GC, then we might look at a card in a 666 // GC alloc region that extends onto a GC LAB, which may not be 667 // parseable. Stop such at the "saved_mark" of the region. 668 if (G1CollectedHeap::heap()->is_gc_active()) { 669 mr = mr.intersection(used_region_at_save_marks()); 670 } else { 671 mr = mr.intersection(used_region()); 672 } 673 if (mr.is_empty()) return NULL; 674 // Otherwise, find the obj that extends onto mr.start(). 675 676 // The intersection of the incoming mr (for the card) and the 677 // allocated part of the region is non-empty. This implies that 678 // we have actually allocated into this region. The code in 679 // G1CollectedHeap.cpp that allocates a new region sets the 680 // is_young tag on the region before allocating. Thus we 681 // safely know if this region is young. 682 if (is_young() && filter_young) { 683 return NULL; 684 } 685 686 assert(!is_young(), "check value of filter_young"); 687 688 // We used to use "block_start_careful" here. But we're actually happy 689 // to update the BOT while we do this... 690 HeapWord* cur = block_start(mr.start()); 691 assert(cur <= mr.start(), "Postcondition"); 692 693 while (cur <= mr.start()) { 694 if (oop(cur)->klass_or_null() == NULL) { 695 // Ran into an unparseable point. 696 return cur; 697 } 698 // Otherwise... 699 int sz = oop(cur)->size(); 700 if (cur + sz > mr.start()) break; 701 // Otherwise, go on. 702 cur = cur + sz; 703 } 704 oop obj; 705 obj = oop(cur); 706 // If we finish this loop... 707 assert(cur <= mr.start() 708 && obj->klass_or_null() != NULL 709 && cur + obj->size() > mr.start(), 710 "Loop postcondition"); 711 if (!g1h->is_obj_dead(obj)) { 712 obj->oop_iterate(cl, mr); 713 } 714 715 HeapWord* next; 716 while (cur < mr.end()) { 717 obj = oop(cur); 718 if (obj->klass_or_null() == NULL) { 719 // Ran into an unparseable point. 720 return cur; 721 }; 722 // Otherwise: 723 next = (cur + obj->size()); 724 if (!g1h->is_obj_dead(obj)) { 725 if (next < mr.end()) { 726 obj->oop_iterate(cl); 727 } else { 728 // this obj spans the boundary. If it's an array, stop at the 729 // boundary. 730 if (obj->is_objArray()) { 731 obj->oop_iterate(cl, mr); 732 } else { 733 obj->oop_iterate(cl); 734 } 735 } 736 } 737 cur = next; 738 } 739 return NULL; 740 } 741 742 void HeapRegion::print() const { print_on(gclog_or_tty); } 743 void HeapRegion::print_on(outputStream* st) const { 744 if (isHumongous()) { 745 if (startsHumongous()) 746 st->print(" HS"); 747 else 748 st->print(" HC"); 749 } else { 750 st->print(" "); 751 } 752 if (in_collection_set()) 753 st->print(" CS"); 754 else if (is_gc_alloc_region()) 755 st->print(" A "); 756 else 757 st->print(" "); 758 if (is_young()) 759 st->print(is_survivor() ? " SU" : " Y "); 760 else 761 st->print(" "); 762 if (is_empty()) 763 st->print(" F"); 764 else 765 st->print(" "); 766 st->print(" %5d", _gc_time_stamp); 767 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT, 768 prev_top_at_mark_start(), next_top_at_mark_start()); 769 G1OffsetTableContigSpace::print_on(st); 770 } 771 772 void HeapRegion::verify(bool allow_dirty) const { 773 bool dummy = false; 774 verify(allow_dirty, /* use_prev_marking */ true, /* failures */ &dummy); 775 } 776 777 #define OBJ_SAMPLE_INTERVAL 0 778 #define BLOCK_SAMPLE_INTERVAL 100 779 780 // This really ought to be commoned up into OffsetTableContigSpace somehow. 781 // We would need a mechanism to make that code skip dead objects. 782 783 void HeapRegion::verify(bool allow_dirty, 784 bool use_prev_marking, 785 bool* failures) const { 786 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 787 *failures = false; 788 HeapWord* p = bottom(); 789 HeapWord* prev_p = NULL; 790 int objs = 0; 791 int blocks = 0; 792 VerifyLiveClosure vl_cl(g1, use_prev_marking); 793 bool is_humongous = isHumongous(); 794 size_t object_num = 0; 795 while (p < top()) { 796 size_t size = oop(p)->size(); 797 if (is_humongous != g1->isHumongous(size)) { 798 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size (" 799 SIZE_FORMAT" words) in a %shumongous region", 800 p, g1->isHumongous(size) ? "" : "non-", 801 size, is_humongous ? "" : "non-"); 802 *failures = true; 803 } 804 object_num += 1; 805 if (blocks == BLOCK_SAMPLE_INTERVAL) { 806 HeapWord* res = block_start_const(p + (size/2)); 807 if (p != res) { 808 gclog_or_tty->print_cr("offset computation 1 for "PTR_FORMAT" and " 809 SIZE_FORMAT" returned "PTR_FORMAT, 810 p, size, res); 811 *failures = true; 812 return; 813 } 814 blocks = 0; 815 } else { 816 blocks++; 817 } 818 if (objs == OBJ_SAMPLE_INTERVAL) { 819 oop obj = oop(p); 820 if (!g1->is_obj_dead_cond(obj, this, use_prev_marking)) { 821 if (obj->is_oop()) { 822 klassOop klass = obj->klass(); 823 if (!klass->is_perm()) { 824 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 825 "not in perm", klass, obj); 826 *failures = true; 827 return; 828 } else if (!klass->is_klass()) { 829 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" " 830 "not a klass", klass, obj); 831 *failures = true; 832 return; 833 } else { 834 vl_cl.set_containing_obj(obj); 835 obj->oop_iterate(&vl_cl); 836 if (vl_cl.failures()) { 837 *failures = true; 838 } 839 if (G1MaxVerifyFailures >= 0 && 840 vl_cl.n_failures() >= G1MaxVerifyFailures) { 841 return; 842 } 843 } 844 } else { 845 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj); 846 *failures = true; 847 return; 848 } 849 } 850 objs = 0; 851 } else { 852 objs++; 853 } 854 prev_p = p; 855 p += size; 856 } 857 HeapWord* rend = end(); 858 HeapWord* rtop = top(); 859 if (rtop < rend) { 860 HeapWord* res = block_start_const(rtop + (rend - rtop) / 2); 861 if (res != rtop) { 862 gclog_or_tty->print_cr("offset computation 2 for "PTR_FORMAT" and " 863 PTR_FORMAT" returned "PTR_FORMAT, 864 rtop, rend, res); 865 *failures = true; 866 return; 867 } 868 } 869 870 if (is_humongous && object_num > 1) { 871 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous " 872 "but has "SIZE_FORMAT", objects", 873 bottom(), end(), object_num); 874 *failures = true; 875 } 876 877 if (p != top()) { 878 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" " 879 "does not match top "PTR_FORMAT, p, top()); 880 *failures = true; 881 return; 882 } 883 } 884 885 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 886 // away eventually. 887 888 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 889 // false ==> we'll do the clearing if there's clearing to be done. 890 ContiguousSpace::initialize(mr, false, mangle_space); 891 _offsets.zero_bottom_entry(); 892 _offsets.initialize_threshold(); 893 if (clear_space) clear(mangle_space); 894 } 895 896 void G1OffsetTableContigSpace::clear(bool mangle_space) { 897 ContiguousSpace::clear(mangle_space); 898 _offsets.zero_bottom_entry(); 899 _offsets.initialize_threshold(); 900 } 901 902 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { 903 Space::set_bottom(new_bottom); 904 _offsets.set_bottom(new_bottom); 905 } 906 907 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) { 908 Space::set_end(new_end); 909 _offsets.resize(new_end - bottom()); 910 } 911 912 void G1OffsetTableContigSpace::print() const { 913 print_short(); 914 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 915 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 916 bottom(), top(), _offsets.threshold(), end()); 917 } 918 919 HeapWord* G1OffsetTableContigSpace::initialize_threshold() { 920 return _offsets.initialize_threshold(); 921 } 922 923 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start, 924 HeapWord* end) { 925 _offsets.alloc_block(start, end); 926 return _offsets.threshold(); 927 } 928 929 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const { 930 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 931 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" ); 932 if (_gc_time_stamp < g1h->get_gc_time_stamp()) 933 return top(); 934 else 935 return ContiguousSpace::saved_mark_word(); 936 } 937 938 void G1OffsetTableContigSpace::set_saved_mark() { 939 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 940 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 941 942 if (_gc_time_stamp < curr_gc_time_stamp) { 943 // The order of these is important, as another thread might be 944 // about to start scanning this region. If it does so after 945 // set_saved_mark and before _gc_time_stamp = ..., then the latter 946 // will be false, and it will pick up top() as the high water mark 947 // of region. If it does so after _gc_time_stamp = ..., then it 948 // will pick up the right saved_mark_word() as the high water mark 949 // of the region. Either way, the behaviour will be correct. 950 ContiguousSpace::set_saved_mark(); 951 OrderAccess::storestore(); 952 _gc_time_stamp = curr_gc_time_stamp; 953 // The following fence is to force a flush of the writes above, but 954 // is strictly not needed because when an allocating worker thread 955 // calls set_saved_mark() it does so under the ParGCRareEvent_lock; 956 // when the lock is released, the write will be flushed. 957 // OrderAccess::fence(); 958 } 959 } 960 961 G1OffsetTableContigSpace:: 962 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray, 963 MemRegion mr, bool is_zeroed) : 964 _offsets(sharedOffsetArray, mr), 965 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 966 _gc_time_stamp(0) 967 { 968 _offsets.set_space(this); 969 initialize(mr, !is_zeroed, SpaceDecorator::Mangle); 970 } 971 972 size_t RegionList::length() { 973 size_t len = 0; 974 HeapRegion* cur = hd(); 975 DEBUG_ONLY(HeapRegion* last = NULL); 976 while (cur != NULL) { 977 len++; 978 DEBUG_ONLY(last = cur); 979 cur = get_next(cur); 980 } 981 assert(last == tl(), "Invariant"); 982 return len; 983 } 984 985 void RegionList::insert_before_head(HeapRegion* r) { 986 assert(well_formed(), "Inv"); 987 set_next(r, hd()); 988 _hd = r; 989 _sz++; 990 if (tl() == NULL) _tl = r; 991 assert(well_formed(), "Inv"); 992 } 993 994 void RegionList::prepend_list(RegionList* new_list) { 995 assert(well_formed(), "Precondition"); 996 assert(new_list->well_formed(), "Precondition"); 997 HeapRegion* new_tl = new_list->tl(); 998 if (new_tl != NULL) { 999 set_next(new_tl, hd()); 1000 _hd = new_list->hd(); 1001 _sz += new_list->sz(); 1002 if (tl() == NULL) _tl = new_list->tl(); 1003 } else { 1004 assert(new_list->hd() == NULL && new_list->sz() == 0, "Inv"); 1005 } 1006 assert(well_formed(), "Inv"); 1007 } 1008 1009 void RegionList::delete_after(HeapRegion* r) { 1010 assert(well_formed(), "Precondition"); 1011 HeapRegion* next = get_next(r); 1012 assert(r != NULL, "Precondition"); 1013 HeapRegion* next_tl = get_next(next); 1014 set_next(r, next_tl); 1015 dec_sz(); 1016 if (next == tl()) { 1017 assert(next_tl == NULL, "Inv"); 1018 _tl = r; 1019 } 1020 assert(well_formed(), "Inv"); 1021 } 1022 1023 HeapRegion* RegionList::pop() { 1024 assert(well_formed(), "Inv"); 1025 HeapRegion* res = hd(); 1026 if (res != NULL) { 1027 _hd = get_next(res); 1028 _sz--; 1029 set_next(res, NULL); 1030 if (sz() == 0) _tl = NULL; 1031 } 1032 assert(well_formed(), "Inv"); 1033 return res; 1034 }