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.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 if (G1HeapRegionSize != GrainBytes) { 158 FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes); 159 } 160 } 161 162 void HeapRegion::reset_after_compaction() { 163 G1ContiguousSpace::reset_after_compaction(); 164 // After a compaction the mark bitmap is invalid, so we must 165 // treat all objects as being inside the unmarked area. 166 zero_marked_bytes(); 167 init_top_at_mark_start(); 168 } 169 170 void HeapRegion::hr_clear(bool keep_remset, bool clear_space, bool locked) { 171 assert(_humongous_start_region == NULL, 172 "we should have already filtered out humongous regions"); 173 assert(!in_collection_set(), 174 "Should not clear heap region %u in the collection set", hrm_index()); 175 176 set_allocation_context(AllocationContext::system()); 177 set_young_index_in_cset(-1); 178 uninstall_surv_rate_group(); 179 set_free(); 180 reset_pre_dummy_top(); 181 182 if (!keep_remset) { 183 if (locked) { 184 rem_set()->clear_locked(); 185 } else { 186 rem_set()->clear(); 187 } 188 } 189 190 zero_marked_bytes(); 191 192 init_top_at_mark_start(); 193 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp(); 194 if (clear_space) clear(SpaceDecorator::Mangle); 195 } 196 197 void HeapRegion::par_clear() { 198 assert(used() == 0, "the region should have been already cleared"); 199 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal"); 200 HeapRegionRemSet* hrrs = rem_set(); 201 hrrs->clear(); 202 CardTableModRefBS* ct_bs = 203 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set()); 204 ct_bs->clear(MemRegion(bottom(), end())); 205 } 206 207 void HeapRegion::calc_gc_efficiency() { 208 // GC efficiency is the ratio of how much space would be 209 // reclaimed over how long we predict it would take to reclaim it. 210 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 211 G1Policy* g1p = g1h->g1_policy(); 212 213 // Retrieve a prediction of the elapsed time for this region for 214 // a mixed gc because the region will only be evacuated during a 215 // mixed gc. 216 double region_elapsed_time_ms = 217 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */); 218 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms; 219 } 220 221 void HeapRegion::set_free() { 222 report_region_type_change(G1HeapRegionTraceType::Free); 223 _type.set_free(); 224 } 225 226 void HeapRegion::set_eden() { 227 report_region_type_change(G1HeapRegionTraceType::Eden); 228 _type.set_eden(); 229 } 230 231 void HeapRegion::set_eden_pre_gc() { 232 report_region_type_change(G1HeapRegionTraceType::Eden); 233 _type.set_eden_pre_gc(); 234 } 235 236 void HeapRegion::set_survivor() { 237 report_region_type_change(G1HeapRegionTraceType::Survivor); 238 _type.set_survivor(); 239 } 240 241 void HeapRegion::set_old() { 242 report_region_type_change(G1HeapRegionTraceType::Old); 243 _type.set_old(); 244 } 245 246 void HeapRegion::set_archive() { 247 report_region_type_change(G1HeapRegionTraceType::Archive); 248 _type.set_archive(); 249 } 250 251 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) { 252 assert(!is_humongous(), "sanity / pre-condition"); 253 assert(top() == bottom(), "should be empty"); 254 255 report_region_type_change(G1HeapRegionTraceType::StartsHumongous); 256 _type.set_starts_humongous(); 257 _humongous_start_region = this; 258 259 _bot_part.set_for_starts_humongous(obj_top, fill_size); 260 } 261 262 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) { 263 assert(!is_humongous(), "sanity / pre-condition"); 264 assert(top() == bottom(), "should be empty"); 265 assert(first_hr->is_starts_humongous(), "pre-condition"); 266 267 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous); 268 _type.set_continues_humongous(); 269 _humongous_start_region = first_hr; 270 } 271 272 void HeapRegion::clear_humongous() { 273 assert(is_humongous(), "pre-condition"); 274 275 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 276 _humongous_start_region = NULL; 277 } 278 279 HeapRegion::HeapRegion(uint hrm_index, 280 G1BlockOffsetTable* bot, 281 MemRegion mr) : 282 G1ContiguousSpace(bot), 283 _hrm_index(hrm_index), 284 _allocation_context(AllocationContext::system()), 285 _humongous_start_region(NULL), 286 _evacuation_failed(false), 287 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), 288 _next(NULL), _prev(NULL), 289 #ifdef ASSERT 290 _containing_set(NULL), 291 #endif // ASSERT 292 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 293 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0), 294 _predicted_bytes_to_copy(0) 295 { 296 _rem_set = new HeapRegionRemSet(bot, this); 297 298 initialize(mr); 299 } 300 301 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 302 assert(_rem_set->is_empty(), "Remembered set must be empty"); 303 304 G1ContiguousSpace::initialize(mr, clear_space, mangle_space); 305 306 hr_clear(false /*par*/, false /*clear_space*/); 307 set_top(bottom()); 308 record_timestamp(); 309 } 310 311 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) { 312 HeapRegionTracer::send_region_type_change(_hrm_index, 313 get_trace_type(), 314 to, 315 (uintptr_t)bottom(), 316 used(), 317 (uint)allocation_context()); 318 } 319 320 CompactibleSpace* HeapRegion::next_compaction_space() const { 321 return G1CollectedHeap::heap()->next_compaction_region(this); 322 } 323 324 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark, 325 bool during_conc_mark) { 326 // We always recreate the prev marking info and we'll explicitly 327 // mark all objects we find to be self-forwarded on the prev 328 // bitmap. So all objects need to be below PTAMS. 329 _prev_marked_bytes = 0; 330 331 if (during_initial_mark) { 332 // During initial-mark, we'll also explicitly mark all objects 333 // we find to be self-forwarded on the next bitmap. So all 334 // objects need to be below NTAMS. 335 _next_top_at_mark_start = top(); 336 _next_marked_bytes = 0; 337 } else if (during_conc_mark) { 338 // During concurrent mark, all objects in the CSet (including 339 // the ones we find to be self-forwarded) are implicitly live. 340 // So all objects need to be above NTAMS. 341 _next_top_at_mark_start = bottom(); 342 _next_marked_bytes = 0; 343 } 344 } 345 346 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark, 347 bool during_conc_mark, 348 size_t marked_bytes) { 349 assert(marked_bytes <= used(), 350 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used()); 351 _prev_top_at_mark_start = top(); 352 _prev_marked_bytes = marked_bytes; 353 } 354 355 bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr, 356 FilterOutOfRegionClosure* cl, 357 jbyte* card_ptr) { 358 assert(card_ptr != NULL, "pre-condition"); 359 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 360 361 // If we're within a stop-world GC, then we might look at a card in a 362 // GC alloc region that extends onto a GC LAB, which may not be 363 // parseable. Stop such at the "scan_top" of the region. 364 if (g1h->is_gc_active()) { 365 mr = mr.intersection(MemRegion(bottom(), scan_top())); 366 } else { 367 mr = mr.intersection(used_region()); 368 } 369 if (mr.is_empty()) { 370 return true; 371 } 372 // Otherwise, find the obj that extends onto mr.start(). 373 374 // The intersection of the incoming mr (for the card) and the 375 // allocated part of the region is non-empty. This implies that 376 // we have actually allocated into this region. The code in 377 // G1CollectedHeap.cpp that allocates a new region sets the 378 // is_young tag on the region before allocating. Thus we 379 // safely know if this region is young. 380 if (is_young()) { 381 return true; 382 } 383 384 // We can only clean the card here, after we make the decision that 385 // the card is not young. 386 *card_ptr = CardTableModRefBS::clean_card_val(); 387 // We must complete this write before we do any of the reads below. 388 OrderAccess::storeload(); 389 390 // Cache the boundaries of the memory region in some const locals 391 HeapWord* const start = mr.start(); 392 HeapWord* const end = mr.end(); 393 394 // Update BOT as needed while finding start of (potential) object. 395 HeapWord* cur = block_start(start); 396 assert(cur <= start, "Postcondition"); 397 398 oop obj; 399 400 HeapWord* next = cur; 401 do { 402 cur = next; 403 obj = oop(cur); 404 if (obj->klass_or_null() == NULL) { 405 // Ran into an unparseable point. 406 assert(!g1h->is_gc_active(), 407 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur)); 408 return false; 409 } 410 // Otherwise... 411 next = cur + block_size(cur); 412 } while (next <= start); 413 414 // If we finish the above loop...We have a parseable object that 415 // begins on or before the start of the memory region, and ends 416 // inside or spans the entire region. 417 assert(cur <= start, "Loop postcondition"); 418 assert(obj->klass_or_null() != NULL, "Loop postcondition"); 419 420 do { 421 obj = oop(cur); 422 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant"); 423 if (obj->klass_or_null() == NULL) { 424 // Ran into an unparseable point. 425 assert(!g1h->is_gc_active(), 426 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur)); 427 return false; 428 } 429 430 // Advance the current pointer. "obj" still points to the object to iterate. 431 cur = cur + block_size(cur); 432 433 if (!g1h->is_obj_dead(obj)) { 434 // Non-objArrays are sometimes marked imprecise at the object start. We 435 // always need to iterate over them in full. 436 // We only iterate over object arrays in full if they are completely contained 437 // in the memory region. 438 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) { 439 obj->oop_iterate(cl); 440 } else { 441 obj->oop_iterate(cl, mr); 442 } 443 } 444 } while (cur < end); 445 446 return true; 447 } 448 449 // Code roots support 450 451 void HeapRegion::add_strong_code_root(nmethod* nm) { 452 HeapRegionRemSet* hrrs = rem_set(); 453 hrrs->add_strong_code_root(nm); 454 } 455 456 void HeapRegion::add_strong_code_root_locked(nmethod* nm) { 457 assert_locked_or_safepoint(CodeCache_lock); 458 HeapRegionRemSet* hrrs = rem_set(); 459 hrrs->add_strong_code_root_locked(nm); 460 } 461 462 void HeapRegion::remove_strong_code_root(nmethod* nm) { 463 HeapRegionRemSet* hrrs = rem_set(); 464 hrrs->remove_strong_code_root(nm); 465 } 466 467 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const { 468 HeapRegionRemSet* hrrs = rem_set(); 469 hrrs->strong_code_roots_do(blk); 470 } 471 472 class VerifyStrongCodeRootOopClosure: public OopClosure { 473 const HeapRegion* _hr; 474 nmethod* _nm; 475 bool _failures; 476 bool _has_oops_in_region; 477 478 template <class T> void do_oop_work(T* p) { 479 T heap_oop = oopDesc::load_heap_oop(p); 480 if (!oopDesc::is_null(heap_oop)) { 481 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 482 483 // Note: not all the oops embedded in the nmethod are in the 484 // current region. We only look at those which are. 485 if (_hr->is_in(obj)) { 486 // Object is in the region. Check that its less than top 487 if (_hr->top() <= (HeapWord*)obj) { 488 // Object is above top 489 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT, 490 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top())); 491 _failures = true; 492 return; 493 } 494 // Nmethod has at least one oop in the current region 495 _has_oops_in_region = true; 496 } 497 } 498 } 499 500 public: 501 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm): 502 _hr(hr), _failures(false), _has_oops_in_region(false) {} 503 504 void do_oop(narrowOop* p) { do_oop_work(p); } 505 void do_oop(oop* p) { do_oop_work(p); } 506 507 bool failures() { return _failures; } 508 bool has_oops_in_region() { return _has_oops_in_region; } 509 }; 510 511 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure { 512 const HeapRegion* _hr; 513 bool _failures; 514 public: 515 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) : 516 _hr(hr), _failures(false) {} 517 518 void do_code_blob(CodeBlob* cb) { 519 nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null(); 520 if (nm != NULL) { 521 // Verify that the nemthod is live 522 if (!nm->is_alive()) { 523 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots", 524 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 525 _failures = true; 526 } else { 527 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm); 528 nm->oops_do(&oop_cl); 529 if (!oop_cl.has_oops_in_region()) { 530 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region", 531 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 532 _failures = true; 533 } else if (oop_cl.failures()) { 534 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT, 535 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 536 _failures = true; 537 } 538 } 539 } 540 } 541 542 bool failures() { return _failures; } 543 }; 544 545 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const { 546 if (!G1VerifyHeapRegionCodeRoots) { 547 // We're not verifying code roots. 548 return; 549 } 550 if (vo == VerifyOption_G1UseMarkWord) { 551 // Marking verification during a full GC is performed after class 552 // unloading, code cache unloading, etc so the strong code roots 553 // attached to each heap region are in an inconsistent state. They won't 554 // be consistent until the strong code roots are rebuilt after the 555 // actual GC. Skip verifying the strong code roots in this particular 556 // time. 557 assert(VerifyDuringGC, "only way to get here"); 558 return; 559 } 560 561 HeapRegionRemSet* hrrs = rem_set(); 562 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length(); 563 564 // if this region is empty then there should be no entries 565 // on its strong code root list 566 if (is_empty()) { 567 if (strong_code_roots_length > 0) { 568 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries", 569 p2i(bottom()), p2i(end()), strong_code_roots_length); 570 *failures = true; 571 } 572 return; 573 } 574 575 if (is_continues_humongous()) { 576 if (strong_code_roots_length > 0) { 577 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries", 578 HR_FORMAT_PARAMS(this), strong_code_roots_length); 579 *failures = true; 580 } 581 return; 582 } 583 584 VerifyStrongCodeRootCodeBlobClosure cb_cl(this); 585 strong_code_roots_do(&cb_cl); 586 587 if (cb_cl.failures()) { 588 *failures = true; 589 } 590 } 591 592 void HeapRegion::print() const { print_on(tty); } 593 void HeapRegion::print_on(outputStream* st) const { 594 st->print("|%4u", this->_hrm_index); 595 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT, 596 p2i(bottom()), p2i(top()), p2i(end())); 597 st->print("|%3d%%", (int) ((double) used() * 100 / capacity())); 598 st->print("|%2s", get_short_type_str()); 599 if (in_collection_set()) { 600 st->print("|CS"); 601 } else { 602 st->print("| "); 603 } 604 st->print("|TS%3u", _gc_time_stamp); 605 st->print("|AC%3u", allocation_context()); 606 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|", 607 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start())); 608 } 609 610 class G1VerificationClosure : public OopClosure { 611 protected: 612 G1CollectedHeap* _g1h; 613 CardTableModRefBS* _bs; 614 oop _containing_obj; 615 bool _failures; 616 int _n_failures; 617 VerifyOption _vo; 618 public: 619 // _vo == UsePrevMarking -> use "prev" marking information, 620 // _vo == UseNextMarking -> use "next" marking information, 621 // _vo == UseMarkWord -> use mark word from object header. 622 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) : 623 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())), 624 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) { 625 } 626 627 void set_containing_obj(oop obj) { 628 _containing_obj = obj; 629 } 630 631 bool failures() { return _failures; } 632 int n_failures() { return _n_failures; } 633 634 void print_object(outputStream* out, oop obj) { 635 #ifdef PRODUCT 636 Klass* k = obj->klass(); 637 const char* class_name = k->external_name(); 638 out->print_cr("class name %s", class_name); 639 #else // PRODUCT 640 obj->print_on(out); 641 #endif // PRODUCT 642 } 643 }; 644 645 class VerifyLiveClosure : public G1VerificationClosure { 646 public: 647 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 648 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 649 virtual void do_oop(oop* p) { do_oop_work(p); } 650 651 template <class T> 652 void do_oop_work(T* p) { 653 assert(_containing_obj != NULL, "Precondition"); 654 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 655 "Precondition"); 656 verify_liveness(p); 657 } 658 659 template <class T> 660 void verify_liveness(T* p) { 661 T heap_oop = oopDesc::load_heap_oop(p); 662 Log(gc, verify) log; 663 if (!oopDesc::is_null(heap_oop)) { 664 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 665 bool failed = false; 666 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) { 667 MutexLockerEx x(ParGCRareEvent_lock, 668 Mutex::_no_safepoint_check_flag); 669 670 if (!_failures) { 671 log.error("----------"); 672 } 673 ResourceMark rm; 674 if (!_g1h->is_in_closed_subset(obj)) { 675 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 676 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 677 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end())); 678 print_object(log.error_stream(), _containing_obj); 679 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj)); 680 } else { 681 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 682 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 683 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 684 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end())); 685 print_object(log.error_stream(), _containing_obj); 686 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 687 p2i(obj), p2i(to->bottom()), p2i(to->end())); 688 print_object(log.error_stream(), obj); 689 } 690 log.error("----------"); 691 _failures = true; 692 failed = true; 693 _n_failures++; 694 } 695 } 696 } 697 }; 698 699 class VerifyRemSetClosure : public G1VerificationClosure { 700 public: 701 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 702 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 703 virtual void do_oop(oop* p) { do_oop_work(p); } 704 705 template <class T> 706 void do_oop_work(T* p) { 707 assert(_containing_obj != NULL, "Precondition"); 708 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 709 "Precondition"); 710 verify_remembered_set(p); 711 } 712 713 template <class T> 714 void verify_remembered_set(T* p) { 715 T heap_oop = oopDesc::load_heap_oop(p); 716 Log(gc, verify) log; 717 if (!oopDesc::is_null(heap_oop)) { 718 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 719 bool failed = false; 720 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 721 HeapRegion* to = _g1h->heap_region_containing(obj); 722 if (from != NULL && to != NULL && 723 from != to && 724 !to->is_pinned()) { 725 jbyte cv_obj = *_bs->byte_for_const(_containing_obj); 726 jbyte cv_field = *_bs->byte_for_const(p); 727 const jbyte dirty = CardTableModRefBS::dirty_card_val(); 728 729 bool is_bad = !(from->is_young() 730 || to->rem_set()->contains_reference(p) 731 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 732 (_containing_obj->is_objArray() ? 733 cv_field == dirty 734 : cv_obj == dirty || cv_field == dirty)); 735 if (is_bad) { 736 MutexLockerEx x(ParGCRareEvent_lock, 737 Mutex::_no_safepoint_check_flag); 738 739 if (!_failures) { 740 log.error("----------"); 741 } 742 log.error("Missing rem set entry:"); 743 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT, 744 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from)); 745 ResourceMark rm; 746 _containing_obj->print_on(log.error_stream()); 747 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to)); 748 if (obj->is_oop()) { 749 obj->print_on(log.error_stream()); 750 } 751 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field); 752 log.error("----------"); 753 _failures = true; 754 if (!failed) _n_failures++; 755 } 756 } 757 } 758 } 759 }; 760 761 // This really ought to be commoned up into OffsetTableContigSpace somehow. 762 // We would need a mechanism to make that code skip dead objects. 763 764 void HeapRegion::verify(VerifyOption vo, 765 bool* failures) const { 766 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 767 *failures = false; 768 HeapWord* p = bottom(); 769 HeapWord* prev_p = NULL; 770 VerifyLiveClosure vl_cl(g1, vo); 771 VerifyRemSetClosure vr_cl(g1, vo); 772 bool is_region_humongous = is_humongous(); 773 size_t object_num = 0; 774 while (p < top()) { 775 oop obj = oop(p); 776 size_t obj_size = block_size(p); 777 object_num += 1; 778 779 if (!g1->is_obj_dead_cond(obj, this, vo)) { 780 if (obj->is_oop()) { 781 Klass* klass = obj->klass(); 782 bool is_metaspace_object = Metaspace::contains(klass) || 783 (vo == VerifyOption_G1UsePrevMarking && 784 ClassLoaderDataGraph::unload_list_contains(klass)); 785 if (!is_metaspace_object) { 786 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 787 "not metadata", p2i(klass), p2i(obj)); 788 *failures = true; 789 return; 790 } else if (!klass->is_klass()) { 791 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 792 "not a klass", p2i(klass), p2i(obj)); 793 *failures = true; 794 return; 795 } else { 796 vl_cl.set_containing_obj(obj); 797 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) { 798 // verify liveness and rem_set 799 vr_cl.set_containing_obj(obj); 800 G1Mux2Closure mux(&vl_cl, &vr_cl); 801 obj->oop_iterate_no_header(&mux); 802 803 if (vr_cl.failures()) { 804 *failures = true; 805 } 806 if (G1MaxVerifyFailures >= 0 && 807 vr_cl.n_failures() >= G1MaxVerifyFailures) { 808 return; 809 } 810 } else { 811 // verify only liveness 812 obj->oop_iterate_no_header(&vl_cl); 813 } 814 if (vl_cl.failures()) { 815 *failures = true; 816 } 817 if (G1MaxVerifyFailures >= 0 && 818 vl_cl.n_failures() >= G1MaxVerifyFailures) { 819 return; 820 } 821 } 822 } else { 823 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 824 *failures = true; 825 return; 826 } 827 } 828 prev_p = p; 829 p += obj_size; 830 } 831 832 if (!is_young() && !is_empty()) { 833 _bot_part.verify(); 834 } 835 836 if (is_region_humongous) { 837 oop obj = oop(this->humongous_start_region()->bottom()); 838 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) { 839 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj)); 840 *failures = true; 841 return; 842 } 843 } 844 845 if (!is_region_humongous && p != top()) { 846 log_error(gc, verify)("end of last object " PTR_FORMAT " " 847 "does not match top " PTR_FORMAT, p2i(p), p2i(top())); 848 *failures = true; 849 return; 850 } 851 852 HeapWord* the_end = end(); 853 // Do some extra BOT consistency checking for addresses in the 854 // range [top, end). BOT look-ups in this range should yield 855 // top. No point in doing that if top == end (there's nothing there). 856 if (p < the_end) { 857 // Look up top 858 HeapWord* addr_1 = p; 859 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1); 860 if (b_start_1 != p) { 861 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " " 862 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 863 p2i(addr_1), p2i(b_start_1), p2i(p)); 864 *failures = true; 865 return; 866 } 867 868 // Look up top + 1 869 HeapWord* addr_2 = p + 1; 870 if (addr_2 < the_end) { 871 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2); 872 if (b_start_2 != p) { 873 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " " 874 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 875 p2i(addr_2), p2i(b_start_2), p2i(p)); 876 *failures = true; 877 return; 878 } 879 } 880 881 // Look up an address between top and end 882 size_t diff = pointer_delta(the_end, p) / 2; 883 HeapWord* addr_3 = p + diff; 884 if (addr_3 < the_end) { 885 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3); 886 if (b_start_3 != p) { 887 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " " 888 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 889 p2i(addr_3), p2i(b_start_3), p2i(p)); 890 *failures = true; 891 return; 892 } 893 } 894 895 // Look up end - 1 896 HeapWord* addr_4 = the_end - 1; 897 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4); 898 if (b_start_4 != p) { 899 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " " 900 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 901 p2i(addr_4), p2i(b_start_4), p2i(p)); 902 *failures = true; 903 return; 904 } 905 } 906 907 verify_strong_code_roots(vo, failures); 908 } 909 910 void HeapRegion::verify() const { 911 bool dummy = false; 912 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 913 } 914 915 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const { 916 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 917 *failures = false; 918 HeapWord* p = bottom(); 919 HeapWord* prev_p = NULL; 920 VerifyRemSetClosure vr_cl(g1, vo); 921 while (p < top()) { 922 oop obj = oop(p); 923 size_t obj_size = block_size(p); 924 925 if (!g1->is_obj_dead_cond(obj, this, vo)) { 926 if (obj->is_oop()) { 927 vr_cl.set_containing_obj(obj); 928 obj->oop_iterate_no_header(&vr_cl); 929 930 if (vr_cl.failures()) { 931 *failures = true; 932 } 933 if (G1MaxVerifyFailures >= 0 && 934 vr_cl.n_failures() >= G1MaxVerifyFailures) { 935 return; 936 } 937 } else { 938 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 939 *failures = true; 940 return; 941 } 942 } 943 944 prev_p = p; 945 p += obj_size; 946 } 947 } 948 949 void HeapRegion::verify_rem_set() const { 950 bool failures = false; 951 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures); 952 guarantee(!failures, "HeapRegion RemSet verification failed"); 953 } 954 955 void HeapRegion::prepare_for_compaction(CompactPoint* cp) { 956 scan_and_forward(this, cp); 957 } 958 959 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 960 // away eventually. 961 962 void G1ContiguousSpace::clear(bool mangle_space) { 963 set_top(bottom()); 964 _scan_top = bottom(); 965 CompactibleSpace::clear(mangle_space); 966 reset_bot(); 967 } 968 969 #ifndef PRODUCT 970 void G1ContiguousSpace::mangle_unused_area() { 971 mangle_unused_area_complete(); 972 } 973 974 void G1ContiguousSpace::mangle_unused_area_complete() { 975 SpaceMangler::mangle_region(MemRegion(top(), end())); 976 } 977 #endif 978 979 void G1ContiguousSpace::print() const { 980 print_short(); 981 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 982 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 983 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end())); 984 } 985 986 HeapWord* G1ContiguousSpace::initialize_threshold() { 987 return _bot_part.initialize_threshold(); 988 } 989 990 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start, 991 HeapWord* end) { 992 _bot_part.alloc_block(start, end); 993 return _bot_part.threshold(); 994 } 995 996 HeapWord* G1ContiguousSpace::scan_top() const { 997 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 998 HeapWord* local_top = top(); 999 OrderAccess::loadload(); 1000 const unsigned local_time_stamp = _gc_time_stamp; 1001 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant"); 1002 if (local_time_stamp < g1h->get_gc_time_stamp()) { 1003 return local_top; 1004 } else { 1005 return _scan_top; 1006 } 1007 } 1008 1009 void G1ContiguousSpace::record_timestamp() { 1010 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1011 uint curr_gc_time_stamp = g1h->get_gc_time_stamp(); 1012 1013 if (_gc_time_stamp < curr_gc_time_stamp) { 1014 // Setting the time stamp here tells concurrent readers to look at 1015 // scan_top to know the maximum allowed address to look at. 1016 1017 // scan_top should be bottom for all regions except for the 1018 // retained old alloc region which should have scan_top == top 1019 HeapWord* st = _scan_top; 1020 guarantee(st == _bottom || st == _top, "invariant"); 1021 1022 _gc_time_stamp = curr_gc_time_stamp; 1023 } 1024 } 1025 1026 void G1ContiguousSpace::record_retained_region() { 1027 // scan_top is the maximum address where it's safe for the next gc to 1028 // scan this region. 1029 _scan_top = top(); 1030 } 1031 1032 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { 1033 object_iterate(blk); 1034 } 1035 1036 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) { 1037 HeapWord* p = bottom(); 1038 while (p < top()) { 1039 if (block_is_obj(p)) { 1040 blk->do_object(oop(p)); 1041 } 1042 p += block_size(p); 1043 } 1044 } 1045 1046 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) : 1047 _bot_part(bot, this), 1048 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 1049 _gc_time_stamp(0) 1050 { 1051 } 1052 1053 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 1054 CompactibleSpace::initialize(mr, clear_space, mangle_space); 1055 _top = bottom(); 1056 _scan_top = bottom(); 1057 set_saved_mark_word(NULL); 1058 reset_bot(); 1059 } 1060