1 /* 2 * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "code/nmethod.hpp" 27 #include "gc/g1/g1BlockOffsetTable.inline.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.hpp" 29 #include "gc/g1/g1HeapRegionTraceType.hpp" 30 #include "gc/g1/g1OopClosures.inline.hpp" 31 #include "gc/g1/heapRegion.inline.hpp" 32 #include "gc/g1/heapRegionBounds.inline.hpp" 33 #include "gc/g1/heapRegionManager.inline.hpp" 34 #include "gc/g1/heapRegionRemSet.hpp" 35 #include "gc/g1/heapRegionTracer.hpp" 36 #include "gc/shared/genOopClosures.inline.hpp" 37 #include "gc/shared/space.inline.hpp" 38 #include "logging/log.hpp" 39 #include "memory/iterator.hpp" 40 #include "memory/resourceArea.hpp" 41 #include "oops/oop.inline.hpp" 42 #include "runtime/atomic.inline.hpp" 43 #include "runtime/orderAccess.inline.hpp" 44 45 int HeapRegion::LogOfHRGrainBytes = 0; 46 int HeapRegion::LogOfHRGrainWords = 0; 47 size_t HeapRegion::GrainBytes = 0; 48 size_t HeapRegion::GrainWords = 0; 49 size_t HeapRegion::CardsPerRegion = 0; 50 51 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1, 52 HeapRegion* hr, 53 G1ParPushHeapRSClosure* cl, 54 CardTableModRefBS::PrecisionStyle precision) : 55 DirtyCardToOopClosure(hr, cl, precision, NULL), 56 _hr(hr), _rs_scan(cl), _g1(g1) { } 57 58 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r, 59 OopClosure* oc) : 60 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { } 61 62 void HeapRegionDCTOC::walk_mem_region(MemRegion mr, 63 HeapWord* bottom, 64 HeapWord* top) { 65 G1CollectedHeap* g1h = _g1; 66 size_t oop_size; 67 HeapWord* cur = bottom; 68 69 // Start filtering what we add to the remembered set. If the object is 70 // not considered dead, either because it is marked (in the mark bitmap) 71 // or it was allocated after marking finished, then we add it. Otherwise 72 // we can safely ignore the object. 73 if (!g1h->is_obj_dead(oop(cur))) { 74 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr); 75 } else { 76 oop_size = _hr->block_size(cur); 77 } 78 79 cur += oop_size; 80 81 if (cur < top) { 82 oop cur_oop = oop(cur); 83 oop_size = _hr->block_size(cur); 84 HeapWord* next_obj = cur + oop_size; 85 while (next_obj < top) { 86 // Keep filtering the remembered set. 87 if (!g1h->is_obj_dead(cur_oop)) { 88 // Bottom lies entirely below top, so we can call the 89 // non-memRegion version of oop_iterate below. 90 cur_oop->oop_iterate(_rs_scan); 91 } 92 cur = next_obj; 93 cur_oop = oop(cur); 94 oop_size = _hr->block_size(cur); 95 next_obj = cur + oop_size; 96 } 97 98 // Last object. Need to do dead-obj filtering here too. 99 if (!g1h->is_obj_dead(oop(cur))) { 100 oop(cur)->oop_iterate(_rs_scan, mr); 101 } 102 } 103 } 104 105 size_t HeapRegion::max_region_size() { 106 return HeapRegionBounds::max_size(); 107 } 108 109 size_t HeapRegion::min_region_size_in_words() { 110 return HeapRegionBounds::min_size() >> LogHeapWordSize; 111 } 112 113 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) { 114 size_t region_size = G1HeapRegionSize; 115 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 116 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2; 117 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(), 118 HeapRegionBounds::min_size()); 119 } 120 121 int region_size_log = log2_long((jlong) region_size); 122 // Recalculate the region size to make sure it's a power of 123 // 2. This means that region_size is the largest power of 2 that's 124 // <= what we've calculated so far. 125 region_size = ((size_t)1 << region_size_log); 126 127 // Now make sure that we don't go over or under our limits. 128 if (region_size < HeapRegionBounds::min_size()) { 129 region_size = HeapRegionBounds::min_size(); 130 } else if (region_size > HeapRegionBounds::max_size()) { 131 region_size = HeapRegionBounds::max_size(); 132 } 133 134 // And recalculate the log. 135 region_size_log = log2_long((jlong) region_size); 136 137 // Now, set up the globals. 138 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 139 LogOfHRGrainBytes = region_size_log; 140 141 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 142 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 143 144 guarantee(GrainBytes == 0, "we should only set it once"); 145 // The cast to int is safe, given that we've bounded region_size by 146 // MIN_REGION_SIZE and MAX_REGION_SIZE. 147 GrainBytes = region_size; 148 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M); 149 150 guarantee(GrainWords == 0, "we should only set it once"); 151 GrainWords = GrainBytes >> LogHeapWordSize; 152 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity"); 153 154 guarantee(CardsPerRegion == 0, "we should only set it once"); 155 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; 156 } 157 158 void HeapRegion::reset_after_compaction() { 159 G1ContiguousSpace::reset_after_compaction(); 160 // After a compaction the mark bitmap is invalid, so we must 161 // treat all objects as being inside the unmarked area. 162 zero_marked_bytes(); 163 init_top_at_mark_start(); 164 } 165 166 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) { 167 assert(_humongous_start_region == NULL, 168 "we should have already filtered out humongous regions"); 169 assert(!in_collection_set(), 170 "Should not clear heap region %u in the collection set", hrm_index()); 171 172 set_allocation_context(AllocationContext::system()); 173 set_young_index_in_cset(-1); 174 uninstall_surv_rate_group(); 175 set_free(); 176 reset_pre_dummy_top(); 177 178 if (!par) { 179 // If this is parallel, this will be done later. 180 HeapRegionRemSet* hrrs = rem_set(); 181 if (locked) { 182 hrrs->clear_locked(); 183 } else { 184 hrrs->clear(); 185 } 186 } 187 zero_marked_bytes(); 188 189 init_top_at_mark_start(); 190 if (clear_space) clear(SpaceDecorator::Mangle); 191 } 192 193 void HeapRegion::par_clear() { 194 assert(used() == 0, "the region should have been already cleared"); 195 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal"); 196 HeapRegionRemSet* hrrs = rem_set(); 197 hrrs->clear(); 198 CardTableModRefBS* ct_bs = 199 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set()); 200 ct_bs->clear(MemRegion(bottom(), end())); 201 } 202 203 void HeapRegion::calc_gc_efficiency() { 204 // GC efficiency is the ratio of how much space would be 205 // reclaimed over how long we predict it would take to reclaim it. 206 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 207 G1CollectorPolicy* g1p = g1h->g1_policy(); 208 209 // Retrieve a prediction of the elapsed time for this region for 210 // a mixed gc because the region will only be evacuated during a 211 // mixed gc. 212 double region_elapsed_time_ms = 213 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */); 214 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms; 215 } 216 217 void HeapRegion::set_free() { 218 report_region_type_change(G1HeapRegionTraceType::Free); 219 _type.set_free(); 220 } 221 222 void HeapRegion::set_eden() { 223 report_region_type_change(G1HeapRegionTraceType::Eden); 224 _type.set_eden(); 225 } 226 227 void HeapRegion::set_eden_pre_gc() { 228 report_region_type_change(G1HeapRegionTraceType::Eden); 229 _type.set_eden_pre_gc(); 230 } 231 232 void HeapRegion::set_survivor() { 233 report_region_type_change(G1HeapRegionTraceType::Survivor); 234 _type.set_survivor(); 235 } 236 237 void HeapRegion::set_old() { 238 report_region_type_change(G1HeapRegionTraceType::Old); 239 _type.set_old(); 240 } 241 242 void HeapRegion::set_archive() { 243 report_region_type_change(G1HeapRegionTraceType::Archive); 244 _type.set_archive(); 245 } 246 247 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) { 248 assert(!is_humongous(), "sanity / pre-condition"); 249 assert(top() == bottom(), "should be empty"); 250 251 report_region_type_change(G1HeapRegionTraceType::StartsHumongous); 252 _type.set_starts_humongous(); 253 _humongous_start_region = this; 254 255 _bot_part.set_for_starts_humongous(obj_top, fill_size); 256 } 257 258 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) { 259 assert(!is_humongous(), "sanity / pre-condition"); 260 assert(top() == bottom(), "should be empty"); 261 assert(first_hr->is_starts_humongous(), "pre-condition"); 262 263 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous); 264 _type.set_continues_humongous(); 265 _humongous_start_region = first_hr; 266 } 267 268 void HeapRegion::clear_humongous() { 269 assert(is_humongous(), "pre-condition"); 270 271 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 272 _humongous_start_region = NULL; 273 } 274 275 HeapRegion::HeapRegion(uint hrm_index, 276 G1BlockOffsetTable* bot, 277 MemRegion mr) : 278 G1ContiguousSpace(bot), 279 _hrm_index(hrm_index), 280 _allocation_context(AllocationContext::system()), 281 _humongous_start_region(NULL), 282 _next_in_special_set(NULL), 283 _evacuation_failed(false), 284 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), 285 _next_young_region(NULL), 286 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), 287 #ifdef ASSERT 288 _containing_set(NULL), 289 #endif // ASSERT 290 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 291 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 292 _predicted_bytes_to_copy(0) 293 { 294 _rem_set = new HeapRegionRemSet(bot, this); 295 296 initialize(mr); 297 } 298 299 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 300 assert(_rem_set->is_empty(), "Remembered set must be empty"); 301 302 G1ContiguousSpace::initialize(mr, clear_space, mangle_space); 303 304 hr_clear(false /*par*/, false /*clear_space*/); 305 set_top(bottom()); 306 record_timestamp(); 307 } 308 309 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) { 310 HeapRegionTracer::send_region_type_change(_hrm_index, 311 get_trace_type(), 312 to, 313 (uintptr_t)bottom(), 314 used(), 315 (uint)allocation_context()); 316 } 317 318 CompactibleSpace* HeapRegion::next_compaction_space() const { 319 return G1CollectedHeap::heap()->next_compaction_region(this); 320 } 321 322 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark, 323 bool during_conc_mark) { 324 // We always recreate the prev marking info and we'll explicitly 325 // mark all objects we find to be self-forwarded on the prev 326 // bitmap. So all objects need to be below PTAMS. 327 _prev_marked_bytes = 0; 328 329 if (during_initial_mark) { 330 // During initial-mark, we'll also explicitly mark all objects 331 // we find to be self-forwarded on the next bitmap. So all 332 // objects need to be below NTAMS. 333 _next_top_at_mark_start = top(); 334 _next_marked_bytes = 0; 335 } else if (during_conc_mark) { 336 // During concurrent mark, all objects in the CSet (including 337 // the ones we find to be self-forwarded) are implicitly live. 338 // So all objects need to be above NTAMS. 339 _next_top_at_mark_start = bottom(); 340 _next_marked_bytes = 0; 341 } 342 } 343 344 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark, 345 bool during_conc_mark, 346 size_t marked_bytes) { 347 assert(marked_bytes <= used(), 348 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used()); 349 _prev_top_at_mark_start = top(); 350 _prev_marked_bytes = marked_bytes; 351 } 352 353 HeapWord* 354 HeapRegion::object_iterate_mem_careful(MemRegion mr, 355 ObjectClosure* cl) { 356 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 357 // We used to use "block_start_careful" here. But we're actually happy 358 // to update the BOT while we do this... 359 HeapWord* cur = block_start(mr.start()); 360 mr = mr.intersection(used_region()); 361 if (mr.is_empty()) return NULL; 362 // Otherwise, find the obj that extends onto mr.start(). 363 364 assert(cur <= mr.start() 365 && (oop(cur)->klass_or_null() == NULL || 366 cur + oop(cur)->size() > mr.start()), 367 "postcondition of block_start"); 368 oop obj; 369 while (cur < mr.end()) { 370 obj = oop(cur); 371 if (obj->klass_or_null() == NULL) { 372 // Ran into an unparseable point. 373 return cur; 374 } else if (!g1h->is_obj_dead(obj)) { 375 cl->do_object(obj); 376 } 377 cur += block_size(cur); 378 } 379 return NULL; 380 } 381 382 HeapWord* 383 HeapRegion:: 384 oops_on_card_seq_iterate_careful(MemRegion mr, 385 FilterOutOfRegionClosure* cl, 386 bool filter_young, 387 jbyte* card_ptr) { 388 // Currently, we should only have to clean the card if filter_young 389 // is true and vice versa. 390 if (filter_young) { 391 assert(card_ptr != NULL, "pre-condition"); 392 } else { 393 assert(card_ptr == NULL, "pre-condition"); 394 } 395 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 396 397 // If we're within a stop-world GC, then we might look at a card in a 398 // GC alloc region that extends onto a GC LAB, which may not be 399 // parseable. Stop such at the "scan_top" of the region. 400 if (g1h->is_gc_active()) { 401 mr = mr.intersection(MemRegion(bottom(), scan_top())); 402 } else { 403 mr = mr.intersection(used_region()); 404 } 405 if (mr.is_empty()) return NULL; 406 // Otherwise, find the obj that extends onto mr.start(). 407 408 // The intersection of the incoming mr (for the card) and the 409 // allocated part of the region is non-empty. This implies that 410 // we have actually allocated into this region. The code in 411 // G1CollectedHeap.cpp that allocates a new region sets the 412 // is_young tag on the region before allocating. Thus we 413 // safely know if this region is young. 414 if (is_young() && filter_young) { 415 return NULL; 416 } 417 418 assert(!is_young(), "check value of filter_young"); 419 420 // We can only clean the card here, after we make the decision that 421 // the card is not young. And we only clean the card if we have been 422 // asked to (i.e., card_ptr != NULL). 423 if (card_ptr != NULL) { 424 *card_ptr = CardTableModRefBS::clean_card_val(); 425 // We must complete this write before we do any of the reads below. 426 OrderAccess::storeload(); 427 } 428 429 // Cache the boundaries of the memory region in some const locals 430 HeapWord* const start = mr.start(); 431 HeapWord* const end = mr.end(); 432 433 // We used to use "block_start_careful" here. But we're actually happy 434 // to update the BOT while we do this... 435 HeapWord* cur = block_start(start); 436 assert(cur <= start, "Postcondition"); 437 438 oop obj; 439 440 HeapWord* next = cur; 441 do { 442 cur = next; 443 obj = oop(cur); 444 if (obj->klass_or_null() == NULL) { 445 // Ran into an unparseable point. 446 return cur; 447 } 448 // Otherwise... 449 next = cur + block_size(cur); 450 } while (next <= start); 451 452 // If we finish the above loop...We have a parseable object that 453 // begins on or before the start of the memory region, and ends 454 // inside or spans the entire region. 455 assert(cur <= start, "Loop postcondition"); 456 assert(obj->klass_or_null() != NULL, "Loop postcondition"); 457 458 do { 459 obj = oop(cur); 460 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant"); 461 if (obj->klass_or_null() == NULL) { 462 // Ran into an unparseable point. 463 return cur; 464 } 465 466 // Advance the current pointer. "obj" still points to the object to iterate. 467 cur = cur + block_size(cur); 468 469 if (!g1h->is_obj_dead(obj)) { 470 // Non-objArrays are sometimes marked imprecise at the object start. We 471 // always need to iterate over them in full. 472 // We only iterate over object arrays in full if they are completely contained 473 // in the memory region. 474 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) { 475 obj->oop_iterate(cl); 476 } else { 477 obj->oop_iterate(cl, mr); 478 } 479 } 480 } while (cur < end); 481 482 return NULL; 483 } 484 485 // Code roots support 486 487 void HeapRegion::add_strong_code_root(nmethod* nm) { 488 HeapRegionRemSet* hrrs = rem_set(); 489 hrrs->add_strong_code_root(nm); 490 } 491 492 void HeapRegion::add_strong_code_root_locked(nmethod* nm) { 493 assert_locked_or_safepoint(CodeCache_lock); 494 HeapRegionRemSet* hrrs = rem_set(); 495 hrrs->add_strong_code_root_locked(nm); 496 } 497 498 void HeapRegion::remove_strong_code_root(nmethod* nm) { 499 HeapRegionRemSet* hrrs = rem_set(); 500 hrrs->remove_strong_code_root(nm); 501 } 502 503 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const { 504 HeapRegionRemSet* hrrs = rem_set(); 505 hrrs->strong_code_roots_do(blk); 506 } 507 508 class VerifyStrongCodeRootOopClosure: public OopClosure { 509 const HeapRegion* _hr; 510 nmethod* _nm; 511 bool _failures; 512 bool _has_oops_in_region; 513 514 template <class T> void do_oop_work(T* p) { 515 T heap_oop = oopDesc::load_heap_oop(p); 516 if (!oopDesc::is_null(heap_oop)) { 517 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 518 519 // Note: not all the oops embedded in the nmethod are in the 520 // current region. We only look at those which are. 521 if (_hr->is_in(obj)) { 522 // Object is in the region. Check that its less than top 523 if (_hr->top() <= (HeapWord*)obj) { 524 // Object is above top 525 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT, 526 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top())); 527 _failures = true; 528 return; 529 } 530 // Nmethod has at least one oop in the current region 531 _has_oops_in_region = true; 532 } 533 } 534 } 535 536 public: 537 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm): 538 _hr(hr), _failures(false), _has_oops_in_region(false) {} 539 540 void do_oop(narrowOop* p) { do_oop_work(p); } 541 void do_oop(oop* p) { do_oop_work(p); } 542 543 bool failures() { return _failures; } 544 bool has_oops_in_region() { return _has_oops_in_region; } 545 }; 546 547 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure { 548 const HeapRegion* _hr; 549 bool _failures; 550 public: 551 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) : 552 _hr(hr), _failures(false) {} 553 554 void do_code_blob(CodeBlob* cb) { 555 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null(); 556 if (nm != NULL) { 557 // Verify that the nemthod is live 558 if (!nm->is_alive()) { 559 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots", 560 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 561 _failures = true; 562 } else { 563 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm); 564 nm->oops_do(&oop_cl); 565 if (!oop_cl.has_oops_in_region()) { 566 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region", 567 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 568 _failures = true; 569 } else if (oop_cl.failures()) { 570 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT, 571 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 572 _failures = true; 573 } 574 } 575 } 576 } 577 578 bool failures() { return _failures; } 579 }; 580 581 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const { 582 if (!G1VerifyHeapRegionCodeRoots) { 583 // We're not verifying code roots. 584 return; 585 } 586 if (vo == VerifyOption_G1UseMarkWord) { 587 // Marking verification during a full GC is performed after class 588 // unloading, code cache unloading, etc so the strong code roots 589 // attached to each heap region are in an inconsistent state. They won't 590 // be consistent until the strong code roots are rebuilt after the 591 // actual GC. Skip verifying the strong code roots in this particular 592 // time. 593 assert(VerifyDuringGC, "only way to get here"); 594 return; 595 } 596 597 HeapRegionRemSet* hrrs = rem_set(); 598 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length(); 599 600 // if this region is empty then there should be no entries 601 // on its strong code root list 602 if (is_empty()) { 603 if (strong_code_roots_length > 0) { 604 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries", 605 p2i(bottom()), p2i(end()), strong_code_roots_length); 606 *failures = true; 607 } 608 return; 609 } 610 611 if (is_continues_humongous()) { 612 if (strong_code_roots_length > 0) { 613 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries", 614 HR_FORMAT_PARAMS(this), strong_code_roots_length); 615 *failures = true; 616 } 617 return; 618 } 619 620 VerifyStrongCodeRootCodeBlobClosure cb_cl(this); 621 strong_code_roots_do(&cb_cl); 622 623 if (cb_cl.failures()) { 624 *failures = true; 625 } 626 } 627 628 void HeapRegion::print() const { print_on(tty); } 629 void HeapRegion::print_on(outputStream* st) const { 630 st->print("|%4u", this->_hrm_index); 631 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT, 632 p2i(bottom()), p2i(top()), p2i(end())); 633 st->print("|%3d%%", (int) ((double) used() * 100 / capacity())); 634 st->print("|%2s", get_short_type_str()); 635 if (in_collection_set()) { 636 st->print("|CS"); 637 } else { 638 st->print("| "); 639 } 640 st->print("|TS%3u", _gc_time_stamp); 641 st->print("|AC%3u", allocation_context()); 642 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|", 643 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start())); 644 } 645 646 class G1VerificationClosure : public OopClosure { 647 protected: 648 G1CollectedHeap* _g1h; 649 CardTableModRefBS* _bs; 650 oop _containing_obj; 651 bool _failures; 652 int _n_failures; 653 VerifyOption _vo; 654 public: 655 // _vo == UsePrevMarking -> use "prev" marking information, 656 // _vo == UseNextMarking -> use "next" marking information, 657 // _vo == UseMarkWord -> use mark word from object header. 658 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) : 659 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())), 660 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) { 661 } 662 663 void set_containing_obj(oop obj) { 664 _containing_obj = obj; 665 } 666 667 bool failures() { return _failures; } 668 int n_failures() { return _n_failures; } 669 670 void print_object(outputStream* out, oop obj) { 671 #ifdef PRODUCT 672 Klass* k = obj->klass(); 673 const char* class_name = k->external_name(); 674 out->print_cr("class name %s", class_name); 675 #else // PRODUCT 676 obj->print_on(out); 677 #endif // PRODUCT 678 } 679 }; 680 681 class VerifyLiveClosure : public G1VerificationClosure { 682 public: 683 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 684 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 685 virtual void do_oop(oop* p) { do_oop_work(p); } 686 687 template <class T> 688 void do_oop_work(T* p) { 689 assert(_containing_obj != NULL, "Precondition"); 690 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 691 "Precondition"); 692 verify_liveness(p); 693 } 694 695 template <class T> 696 void verify_liveness(T* p) { 697 T heap_oop = oopDesc::load_heap_oop(p); 698 Log(gc, verify) log; 699 if (!oopDesc::is_null(heap_oop)) { 700 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 701 bool failed = false; 702 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) { 703 MutexLockerEx x(ParGCRareEvent_lock, 704 Mutex::_no_safepoint_check_flag); 705 706 if (!_failures) { 707 log.error("----------"); 708 } 709 ResourceMark rm; 710 if (!_g1h->is_in_closed_subset(obj)) { 711 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 712 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 713 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end())); 714 print_object(log.error_stream(), _containing_obj); 715 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj)); 716 } else { 717 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 718 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 719 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 720 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end())); 721 print_object(log.error_stream(), _containing_obj); 722 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 723 p2i(obj), p2i(to->bottom()), p2i(to->end())); 724 print_object(log.error_stream(), obj); 725 } 726 log.error("----------"); 727 _failures = true; 728 failed = true; 729 _n_failures++; 730 } 731 } 732 } 733 }; 734 735 class VerifyRemSetClosure : public G1VerificationClosure { 736 public: 737 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 738 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 739 virtual void do_oop(oop* p) { do_oop_work(p); } 740 741 template <class T> 742 void do_oop_work(T* p) { 743 assert(_containing_obj != NULL, "Precondition"); 744 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 745 "Precondition"); 746 verify_remembered_set(p); 747 } 748 749 template <class T> 750 void verify_remembered_set(T* p) { 751 T heap_oop = oopDesc::load_heap_oop(p); 752 Log(gc, verify) log; 753 if (!oopDesc::is_null(heap_oop)) { 754 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 755 bool failed = false; 756 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 757 HeapRegion* to = _g1h->heap_region_containing(obj); 758 if (from != NULL && to != NULL && 759 from != to && 760 !to->is_pinned()) { 761 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 762 jbyte cv_field = *_bs->byte_for_const(p); 763 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 764 765 bool is_bad = !(from->is_young() 766 || to->rem_set()->contains_reference(p) 767 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 768 (_containing_obj->is_objArray() ? 769 cv_field == dirty 770 : cv_obj == dirty || cv_field == dirty)); 771 if (is_bad) { 772 MutexLockerEx x(ParGCRareEvent_lock, 773 Mutex::_no_safepoint_check_flag); 774 775 if (!_failures) { 776 log.error("----------"); 777 } 778 log.error("Missing rem set entry:"); 779 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT, 780 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from)); 781 ResourceMark rm; 782 _containing_obj->print_on(log.error_stream()); 783 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to)); 784 if (obj->is_oop()) { 785 obj->print_on(log.error_stream()); 786 } 787 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field); 788 log.error("----------"); 789 _failures = true; 790 if (!failed) _n_failures++; 791 } 792 } 793 } 794 } 795 }; 796 797 // This really ought to be commoned up into OffsetTableContigSpace somehow. 798 // We would need a mechanism to make that code skip dead objects. 799 800 void HeapRegion::verify(VerifyOption vo, 801 bool* failures) const { 802 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 803 *failures = false; 804 HeapWord* p = bottom(); 805 HeapWord* prev_p = NULL; 806 VerifyLiveClosure vl_cl(g1, vo); 807 VerifyRemSetClosure vr_cl(g1, vo); 808 bool is_region_humongous = is_humongous(); 809 size_t object_num = 0; 810 while (p < top()) { 811 oop obj = oop(p); 812 size_t obj_size = block_size(p); 813 object_num += 1; 814 815 if (!g1->is_obj_dead_cond(obj, this, vo)) { 816 if (obj->is_oop()) { 817 Klass* klass = obj->klass(); 818 bool is_metaspace_object = Metaspace::contains(klass) || 819 (vo == VerifyOption_G1UsePrevMarking && 820 ClassLoaderDataGraph::unload_list_contains(klass)); 821 if (!is_metaspace_object) { 822 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 823 "not metadata", p2i(klass), p2i(obj)); 824 *failures = true; 825 return; 826 } else if (!klass->is_klass()) { 827 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 828 "not a klass", p2i(klass), p2i(obj)); 829 *failures = true; 830 return; 831 } else { 832 vl_cl.set_containing_obj(obj); 833 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) { 834 // verify liveness and rem_set 835 vr_cl.set_containing_obj(obj); 836 G1Mux2Closure mux(&vl_cl, &vr_cl); 837 obj->oop_iterate_no_header(&mux); 838 839 if (vr_cl.failures()) { 840 *failures = true; 841 } 842 if (G1MaxVerifyFailures >= 0 && 843 vr_cl.n_failures() >= G1MaxVerifyFailures) { 844 return; 845 } 846 } else { 847 // verify only liveness 848 obj->oop_iterate_no_header(&vl_cl); 849 } 850 if (vl_cl.failures()) { 851 *failures = true; 852 } 853 if (G1MaxVerifyFailures >= 0 && 854 vl_cl.n_failures() >= G1MaxVerifyFailures) { 855 return; 856 } 857 } 858 } else { 859 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 860 *failures = true; 861 return; 862 } 863 } 864 prev_p = p; 865 p += obj_size; 866 } 867 868 if (!is_young() && !is_empty()) { 869 _bot_part.verify(); 870 } 871 872 if (is_region_humongous) { 873 oop obj = oop(this->humongous_start_region()->bottom()); 874 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) { 875 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj)); 876 *failures = true; 877 return; 878 } 879 } 880 881 if (!is_region_humongous && p != top()) { 882 log_error(gc, verify)("end of last object " PTR_FORMAT " " 883 "does not match top " PTR_FORMAT, p2i(p), p2i(top())); 884 *failures = true; 885 return; 886 } 887 888 HeapWord* the_end = end(); 889 // Do some extra BOT consistency checking for addresses in the 890 // range [top, end). BOT look-ups in this range should yield 891 // top. No point in doing that if top == end (there's nothing there). 892 if (p < the_end) { 893 // Look up top 894 HeapWord* addr_1 = p; 895 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1); 896 if (b_start_1 != p) { 897 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " " 898 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 899 p2i(addr_1), p2i(b_start_1), p2i(p)); 900 *failures = true; 901 return; 902 } 903 904 // Look up top + 1 905 HeapWord* addr_2 = p + 1; 906 if (addr_2 < the_end) { 907 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2); 908 if (b_start_2 != p) { 909 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " " 910 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 911 p2i(addr_2), p2i(b_start_2), p2i(p)); 912 *failures = true; 913 return; 914 } 915 } 916 917 // Look up an address between top and end 918 size_t diff = pointer_delta(the_end, p) / 2; 919 HeapWord* addr_3 = p + diff; 920 if (addr_3 < the_end) { 921 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3); 922 if (b_start_3 != p) { 923 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " " 924 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 925 p2i(addr_3), p2i(b_start_3), p2i(p)); 926 *failures = true; 927 return; 928 } 929 } 930 931 // Look up end - 1 932 HeapWord* addr_4 = the_end - 1; 933 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4); 934 if (b_start_4 != p) { 935 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " " 936 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 937 p2i(addr_4), p2i(b_start_4), p2i(p)); 938 *failures = true; 939 return; 940 } 941 } 942 943 verify_strong_code_roots(vo, failures); 944 } 945 946 void HeapRegion::verify() const { 947 bool dummy = false; 948 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 949 } 950 951 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const { 952 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 953 *failures = false; 954 HeapWord* p = bottom(); 955 HeapWord* prev_p = NULL; 956 VerifyRemSetClosure vr_cl(g1, vo); 957 while (p < top()) { 958 oop obj = oop(p); 959 size_t obj_size = block_size(p); 960 961 if (!g1->is_obj_dead_cond(obj, this, vo)) { 962 if (obj->is_oop()) { 963 vr_cl.set_containing_obj(obj); 964 obj->oop_iterate_no_header(&vr_cl); 965 966 if (vr_cl.failures()) { 967 *failures = true; 968 } 969 if (G1MaxVerifyFailures >= 0 && 970 vr_cl.n_failures() >= G1MaxVerifyFailures) { 971 return; 972 } 973 } else { 974 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 975 *failures = true; 976 return; 977 } 978 } 979 980 prev_p = p; 981 p += obj_size; 982 } 983 } 984 985 void HeapRegion::verify_rem_set() const { 986 bool failures = false; 987 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures); 988 guarantee(!failures, "HeapRegion RemSet verification failed"); 989 } 990 991 void HeapRegion::prepare_for_compaction(CompactPoint* cp) { 992 scan_and_forward(this, cp); 993 } 994 995 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 996 // away eventually. 997 998 void G1ContiguousSpace::clear(bool mangle_space) { 999 set_top(bottom()); 1000 _scan_top = bottom(); 1001 CompactibleSpace::clear(mangle_space); 1002 reset_bot(); 1003 } 1004 1005 #ifndef PRODUCT 1006 void G1ContiguousSpace::mangle_unused_area() { 1007 mangle_unused_area_complete(); 1008 } 1009 1010 void G1ContiguousSpace::mangle_unused_area_complete() { 1011 SpaceMangler::mangle_region(MemRegion(top(), end())); 1012 } 1013 #endif 1014 1015 void G1ContiguousSpace::print() const { 1016 print_short(); 1017 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 1018 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 1019 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end())); 1020 } 1021 1022 HeapWord* G1ContiguousSpace::initialize_threshold() { 1023 return _bot_part.initialize_threshold(); 1024 } 1025 1026 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start, 1027 HeapWord* end) { 1028 _bot_part.alloc_block(start, end); 1029 return _bot_part.threshold(); 1030 } 1031 1032 HeapWord* G1ContiguousSpace::scan_top() const { 1033 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1034 HeapWord* local_top = top(); 1035 OrderAccess::loadload(); 1036 const unsigned local_time_stamp = _gc_time_stamp; 1037 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant"); 1038 if (local_time_stamp < g1h->get_gc_time_stamp()) { 1039 return local_top; 1040 } else { 1041 return _scan_top; 1042 } 1043 } 1044 1045 void G1ContiguousSpace::record_timestamp() { 1046 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1047 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp(); 1048 1049 if (_gc_time_stamp < curr_gc_time_stamp) { 1050 // Setting the time stamp here tells concurrent readers to look at 1051 // scan_top to know the maximum allowed address to look at. 1052 1053 // scan_top should be bottom for all regions except for the 1054 // retained old alloc region which should have scan_top == top 1055 HeapWord* st = _scan_top; 1056 guarantee(st == _bottom || st == _top, "invariant"); 1057 1058 _gc_time_stamp = curr_gc_time_stamp; 1059 } 1060 } 1061 1062 void G1ContiguousSpace::record_retained_region() { 1063 // scan_top is the maximum address where it's safe for the next gc to 1064 // scan this region. 1065 _scan_top = top(); 1066 } 1067 1068 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { 1069 object_iterate(blk); 1070 } 1071 1072 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) { 1073 HeapWord* p = bottom(); 1074 while (p < top()) { 1075 if (block_is_obj(p)) { 1076 blk->do_object(oop(p)); 1077 } 1078 p += block_size(p); 1079 } 1080 } 1081 1082 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) : 1083 _bot_part(bot, this), 1084 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 1085 _gc_time_stamp(0) 1086 { 1087 } 1088 1089 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 1090 CompactibleSpace::initialize(mr, clear_space, mangle_space); 1091 _top = bottom(); 1092 _scan_top = bottom(); 1093 set_saved_mark_word(NULL); 1094 reset_bot(); 1095 } 1096