1 /* 2 * Copyright (c) 2001, 2017, 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 CardTable::PrecisionStyle precision) : 55 DirtyCardToOopClosure(hr, cl, precision, NULL), 56 _hr(hr), _rs_scan(cl), _g1(g1) { } 57 58 void HeapRegionDCTOC::walk_mem_region(MemRegion mr, 59 HeapWord* bottom, 60 HeapWord* top) { 61 G1CollectedHeap* g1h = _g1; 62 size_t oop_size; 63 HeapWord* cur = bottom; 64 65 // Start filtering what we add to the remembered set. If the object is 66 // not considered dead, either because it is marked (in the mark bitmap) 67 // or it was allocated after marking finished, then we add it. Otherwise 68 // we can safely ignore the object. 69 if (!g1h->is_obj_dead(oop(cur))) { 70 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr); 71 } else { 72 oop_size = _hr->block_size(cur); 73 } 74 75 cur += oop_size; 76 77 if (cur < top) { 78 oop cur_oop = oop(cur); 79 oop_size = _hr->block_size(cur); 80 HeapWord* next_obj = cur + oop_size; 81 while (next_obj < top) { 82 // Keep filtering the remembered set. 83 if (!g1h->is_obj_dead(cur_oop)) { 84 // Bottom lies entirely below top, so we can call the 85 // non-memRegion version of oop_iterate below. 86 cur_oop->oop_iterate(_rs_scan); 87 } 88 cur = next_obj; 89 cur_oop = oop(cur); 90 oop_size = _hr->block_size(cur); 91 next_obj = cur + oop_size; 92 } 93 94 // Last object. Need to do dead-obj filtering here too. 95 if (!g1h->is_obj_dead(oop(cur))) { 96 oop(cur)->oop_iterate(_rs_scan, mr); 97 } 98 } 99 } 100 101 size_t HeapRegion::max_region_size() { 102 return HeapRegionBounds::max_size(); 103 } 104 105 size_t HeapRegion::min_region_size_in_words() { 106 return HeapRegionBounds::min_size() >> LogHeapWordSize; 107 } 108 109 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) { 110 size_t region_size = G1HeapRegionSize; 111 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { 112 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2; 113 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(), 114 HeapRegionBounds::min_size()); 115 } 116 117 int region_size_log = log2_long((jlong) region_size); 118 // Recalculate the region size to make sure it's a power of 119 // 2. This means that region_size is the largest power of 2 that's 120 // <= what we've calculated so far. 121 region_size = ((size_t)1 << region_size_log); 122 123 // Now make sure that we don't go over or under our limits. 124 if (region_size < HeapRegionBounds::min_size()) { 125 region_size = HeapRegionBounds::min_size(); 126 } else if (region_size > HeapRegionBounds::max_size()) { 127 region_size = HeapRegionBounds::max_size(); 128 } 129 130 // And recalculate the log. 131 region_size_log = log2_long((jlong) region_size); 132 133 // Now, set up the globals. 134 guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); 135 LogOfHRGrainBytes = region_size_log; 136 137 guarantee(LogOfHRGrainWords == 0, "we should only set it once"); 138 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; 139 140 guarantee(GrainBytes == 0, "we should only set it once"); 141 // The cast to int is safe, given that we've bounded region_size by 142 // MIN_REGION_SIZE and MAX_REGION_SIZE. 143 GrainBytes = region_size; 144 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M); 145 146 guarantee(GrainWords == 0, "we should only set it once"); 147 GrainWords = GrainBytes >> LogHeapWordSize; 148 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity"); 149 150 guarantee(CardsPerRegion == 0, "we should only set it once"); 151 CardsPerRegion = GrainBytes >> G1CardTable::card_shift; 152 153 if (G1HeapRegionSize != GrainBytes) { 154 FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes); 155 } 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 keep_remset, 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 (!keep_remset) { 179 if (locked) { 180 rem_set()->clear_locked(); 181 } else { 182 rem_set()->clear(); 183 } 184 } 185 186 zero_marked_bytes(); 187 188 init_top_at_mark_start(); 189 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp(); 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 G1CardTable* ct = G1CollectedHeap::heap()->g1_card_table(); 199 ct->clear(MemRegion(bottom(), end())); 200 } 201 202 void HeapRegion::calc_gc_efficiency() { 203 // GC efficiency is the ratio of how much space would be 204 // reclaimed over how long we predict it would take to reclaim it. 205 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 206 G1Policy* g1p = g1h->g1_policy(); 207 208 // Retrieve a prediction of the elapsed time for this region for 209 // a mixed gc because the region will only be evacuated during a 210 // mixed gc. 211 double region_elapsed_time_ms = 212 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */); 213 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms; 214 } 215 216 void HeapRegion::set_free() { 217 report_region_type_change(G1HeapRegionTraceType::Free); 218 _type.set_free(); 219 } 220 221 void HeapRegion::set_eden() { 222 report_region_type_change(G1HeapRegionTraceType::Eden); 223 _type.set_eden(); 224 } 225 226 void HeapRegion::set_eden_pre_gc() { 227 report_region_type_change(G1HeapRegionTraceType::Eden); 228 _type.set_eden_pre_gc(); 229 } 230 231 void HeapRegion::set_survivor() { 232 report_region_type_change(G1HeapRegionTraceType::Survivor); 233 _type.set_survivor(); 234 } 235 236 void HeapRegion::set_old() { 237 report_region_type_change(G1HeapRegionTraceType::Old); 238 _type.set_old(); 239 } 240 241 void HeapRegion::set_archive() { 242 report_region_type_change(G1HeapRegionTraceType::Archive); 243 _type.set_archive(); 244 } 245 246 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) { 247 assert(!is_humongous(), "sanity / pre-condition"); 248 assert(top() == bottom(), "should be empty"); 249 250 report_region_type_change(G1HeapRegionTraceType::StartsHumongous); 251 _type.set_starts_humongous(); 252 _humongous_start_region = this; 253 254 _bot_part.set_for_starts_humongous(obj_top, fill_size); 255 } 256 257 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) { 258 assert(!is_humongous(), "sanity / pre-condition"); 259 assert(top() == bottom(), "should be empty"); 260 assert(first_hr->is_starts_humongous(), "pre-condition"); 261 262 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous); 263 _type.set_continues_humongous(); 264 _humongous_start_region = first_hr; 265 266 _bot_part.set_object_can_span(true); 267 } 268 269 void HeapRegion::clear_humongous() { 270 assert(is_humongous(), "pre-condition"); 271 272 assert(capacity() == HeapRegion::GrainBytes, "pre-condition"); 273 _humongous_start_region = NULL; 274 275 _bot_part.set_object_can_span(false); 276 } 277 278 HeapRegion::HeapRegion(uint hrm_index, 279 G1BlockOffsetTable* bot, 280 MemRegion mr) : 281 G1ContiguousSpace(bot), 282 _hrm_index(hrm_index), 283 _allocation_context(AllocationContext::system()), 284 _humongous_start_region(NULL), 285 _evacuation_failed(false), 286 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), 287 _next(NULL), _prev(NULL), 288 #ifdef ASSERT 289 _containing_set(NULL), 290 #endif // ASSERT 291 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1), 292 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(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(size_t marked_bytes) { 345 assert(marked_bytes <= used(), 346 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used()); 347 _prev_top_at_mark_start = top(); 348 _prev_marked_bytes = marked_bytes; 349 } 350 351 // Humongous objects are allocated directly in the old-gen. Need 352 // special handling for concurrent processing encountering an 353 // in-progress allocation. 354 static bool do_oops_on_card_in_humongous(MemRegion mr, 355 G1UpdateRSOrPushRefOopClosure* cl, 356 HeapRegion* hr, 357 G1CollectedHeap* g1h) { 358 assert(hr->is_humongous(), "precondition"); 359 HeapRegion* sr = hr->humongous_start_region(); 360 oop obj = oop(sr->bottom()); 361 362 // If concurrent and klass_or_null is NULL, then space has been 363 // allocated but the object has not yet been published by setting 364 // the klass. That can only happen if the card is stale. However, 365 // we've already set the card clean, so we must return failure, 366 // since the allocating thread could have performed a write to the 367 // card that might be missed otherwise. 368 if (!g1h->is_gc_active() && (obj->klass_or_null_acquire() == NULL)) { 369 return false; 370 } 371 372 // We have a well-formed humongous object at the start of sr. 373 // Only filler objects follow a humongous object in the containing 374 // regions, and we can ignore those. So only process the one 375 // humongous object. 376 if (!g1h->is_obj_dead(obj, sr)) { 377 if (obj->is_objArray() || (sr->bottom() < mr.start())) { 378 // objArrays are always marked precisely, so limit processing 379 // with mr. Non-objArrays might be precisely marked, and since 380 // it's humongous it's worthwhile avoiding full processing. 381 // However, the card could be stale and only cover filler 382 // objects. That should be rare, so not worth checking for; 383 // instead let it fall out from the bounded iteration. 384 obj->oop_iterate(cl, mr); 385 } else { 386 // If obj is not an objArray and mr contains the start of the 387 // obj, then this could be an imprecise mark, and we need to 388 // process the entire object. 389 obj->oop_iterate(cl); 390 } 391 } 392 return true; 393 } 394 395 bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr, 396 G1UpdateRSOrPushRefOopClosure* cl) { 397 assert(MemRegion(bottom(), end()).contains(mr), "Card region not in heap region"); 398 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 399 400 // Special handling for humongous regions. 401 if (is_humongous()) { 402 return do_oops_on_card_in_humongous(mr, cl, this, g1h); 403 } 404 assert(is_old(), "precondition"); 405 406 // Because mr has been trimmed to what's been allocated in this 407 // region, the parts of the heap that are examined here are always 408 // parsable; there's no need to use klass_or_null to detect 409 // in-progress allocation. 410 411 // Cache the boundaries of the memory region in some const locals 412 HeapWord* const start = mr.start(); 413 HeapWord* const end = mr.end(); 414 415 // Find the obj that extends onto mr.start(). 416 // Update BOT as needed while finding start of (possibly dead) 417 // object containing the start of the region. 418 HeapWord* cur = block_start(start); 419 420 #ifdef ASSERT 421 { 422 assert(cur <= start, 423 "cur: " PTR_FORMAT ", start: " PTR_FORMAT, p2i(cur), p2i(start)); 424 HeapWord* next = cur + block_size(cur); 425 assert(start < next, 426 "start: " PTR_FORMAT ", next: " PTR_FORMAT, p2i(start), p2i(next)); 427 } 428 #endif 429 430 do { 431 oop obj = oop(cur); 432 assert(obj->is_oop(true), "Not an oop at " PTR_FORMAT, p2i(cur)); 433 assert(obj->klass_or_null() != NULL, 434 "Unparsable heap at " PTR_FORMAT, p2i(cur)); 435 436 if (g1h->is_obj_dead(obj, this)) { 437 // Carefully step over dead object. 438 cur += block_size(cur); 439 } else { 440 // Step over live object, and process its references. 441 cur += obj->size(); 442 // Non-objArrays are usually marked imprecise at the object 443 // start, in which case we need to iterate over them in full. 444 // objArrays are precisely marked, but can still be iterated 445 // over in full if completely covered. 446 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) { 447 obj->oop_iterate(cl); 448 } else { 449 obj->oop_iterate(cl, mr); 450 } 451 } 452 } while (cur < end); 453 454 return true; 455 } 456 457 // Code roots support 458 459 void HeapRegion::add_strong_code_root(nmethod* nm) { 460 HeapRegionRemSet* hrrs = rem_set(); 461 hrrs->add_strong_code_root(nm); 462 } 463 464 void HeapRegion::add_strong_code_root_locked(nmethod* nm) { 465 assert_locked_or_safepoint(CodeCache_lock); 466 HeapRegionRemSet* hrrs = rem_set(); 467 hrrs->add_strong_code_root_locked(nm); 468 } 469 470 void HeapRegion::remove_strong_code_root(nmethod* nm) { 471 HeapRegionRemSet* hrrs = rem_set(); 472 hrrs->remove_strong_code_root(nm); 473 } 474 475 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const { 476 HeapRegionRemSet* hrrs = rem_set(); 477 hrrs->strong_code_roots_do(blk); 478 } 479 480 class VerifyStrongCodeRootOopClosure: public OopClosure { 481 const HeapRegion* _hr; 482 bool _failures; 483 bool _has_oops_in_region; 484 485 template <class T> void do_oop_work(T* p) { 486 T heap_oop = oopDesc::load_heap_oop(p); 487 if (!oopDesc::is_null(heap_oop)) { 488 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 489 490 // Note: not all the oops embedded in the nmethod are in the 491 // current region. We only look at those which are. 492 if (_hr->is_in(obj)) { 493 // Object is in the region. Check that its less than top 494 if (_hr->top() <= (HeapWord*)obj) { 495 // Object is above top 496 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT, 497 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top())); 498 _failures = true; 499 return; 500 } 501 // Nmethod has at least one oop in the current region 502 _has_oops_in_region = true; 503 } 504 } 505 } 506 507 public: 508 VerifyStrongCodeRootOopClosure(const HeapRegion* hr): 509 _hr(hr), _failures(false), _has_oops_in_region(false) {} 510 511 void do_oop(narrowOop* p) { do_oop_work(p); } 512 void do_oop(oop* p) { do_oop_work(p); } 513 514 bool failures() { return _failures; } 515 bool has_oops_in_region() { return _has_oops_in_region; } 516 }; 517 518 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure { 519 const HeapRegion* _hr; 520 bool _failures; 521 public: 522 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) : 523 _hr(hr), _failures(false) {} 524 525 void do_code_blob(CodeBlob* cb) { 526 nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null(); 527 if (nm != NULL) { 528 // Verify that the nemthod is live 529 if (!nm->is_alive()) { 530 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots", 531 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 532 _failures = true; 533 } else { 534 VerifyStrongCodeRootOopClosure oop_cl(_hr); 535 nm->oops_do(&oop_cl); 536 if (!oop_cl.has_oops_in_region()) { 537 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region", 538 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 539 _failures = true; 540 } else if (oop_cl.failures()) { 541 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT, 542 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm)); 543 _failures = true; 544 } 545 } 546 } 547 } 548 549 bool failures() { return _failures; } 550 }; 551 552 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const { 553 if (!G1VerifyHeapRegionCodeRoots) { 554 // We're not verifying code roots. 555 return; 556 } 557 if (vo == VerifyOption_G1UseMarkWord) { 558 // Marking verification during a full GC is performed after class 559 // unloading, code cache unloading, etc so the strong code roots 560 // attached to each heap region are in an inconsistent state. They won't 561 // be consistent until the strong code roots are rebuilt after the 562 // actual GC. Skip verifying the strong code roots in this particular 563 // time. 564 assert(VerifyDuringGC, "only way to get here"); 565 return; 566 } 567 568 HeapRegionRemSet* hrrs = rem_set(); 569 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length(); 570 571 // if this region is empty then there should be no entries 572 // on its strong code root list 573 if (is_empty()) { 574 if (strong_code_roots_length > 0) { 575 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries", 576 p2i(bottom()), p2i(end()), strong_code_roots_length); 577 *failures = true; 578 } 579 return; 580 } 581 582 if (is_continues_humongous()) { 583 if (strong_code_roots_length > 0) { 584 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries", 585 HR_FORMAT_PARAMS(this), strong_code_roots_length); 586 *failures = true; 587 } 588 return; 589 } 590 591 VerifyStrongCodeRootCodeBlobClosure cb_cl(this); 592 strong_code_roots_do(&cb_cl); 593 594 if (cb_cl.failures()) { 595 *failures = true; 596 } 597 } 598 599 void HeapRegion::print() const { print_on(tty); } 600 void HeapRegion::print_on(outputStream* st) const { 601 st->print("|%4u", this->_hrm_index); 602 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT, 603 p2i(bottom()), p2i(top()), p2i(end())); 604 st->print("|%3d%%", (int) ((double) used() * 100 / capacity())); 605 st->print("|%2s", get_short_type_str()); 606 if (in_collection_set()) { 607 st->print("|CS"); 608 } else { 609 st->print("| "); 610 } 611 st->print("|TS%3u", _gc_time_stamp); 612 st->print("|AC%3u", allocation_context()); 613 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|", 614 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start())); 615 } 616 617 class G1VerificationClosure : public OopClosure { 618 protected: 619 G1CollectedHeap* _g1h; 620 G1CardTable *_ct; 621 oop _containing_obj; 622 bool _failures; 623 int _n_failures; 624 VerifyOption _vo; 625 public: 626 // _vo == UsePrevMarking -> use "prev" marking information, 627 // _vo == UseNextMarking -> use "next" marking information, 628 // _vo == UseMarkWord -> use mark word from object header. 629 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) : 630 _g1h(g1h), _ct(g1h->g1_card_table()), 631 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) { 632 } 633 634 void set_containing_obj(oop obj) { 635 _containing_obj = obj; 636 } 637 638 bool failures() { return _failures; } 639 int n_failures() { return _n_failures; } 640 641 void print_object(outputStream* out, oop obj) { 642 #ifdef PRODUCT 643 Klass* k = obj->klass(); 644 const char* class_name = k->external_name(); 645 out->print_cr("class name %s", class_name); 646 #else // PRODUCT 647 obj->print_on(out); 648 #endif // PRODUCT 649 } 650 }; 651 652 class VerifyLiveClosure : public G1VerificationClosure { 653 public: 654 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 655 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 656 virtual void do_oop(oop* p) { do_oop_work(p); } 657 658 template <class T> 659 void do_oop_work(T* p) { 660 assert(_containing_obj != NULL, "Precondition"); 661 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 662 "Precondition"); 663 verify_liveness(p); 664 } 665 666 template <class T> 667 void verify_liveness(T* p) { 668 T heap_oop = oopDesc::load_heap_oop(p); 669 Log(gc, verify) log; 670 if (!oopDesc::is_null(heap_oop)) { 671 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 672 bool failed = false; 673 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) { 674 MutexLockerEx x(ParGCRareEvent_lock, 675 Mutex::_no_safepoint_check_flag); 676 677 if (!_failures) { 678 log.error("----------"); 679 } 680 ResourceMark rm; 681 if (!_g1h->is_in_closed_subset(obj)) { 682 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 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 obj " PTR_FORMAT " not in the heap", p2i(obj)); 687 } else { 688 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 689 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj); 690 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 691 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end())); 692 print_object(log.error_stream(), _containing_obj); 693 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")", 694 p2i(obj), p2i(to->bottom()), p2i(to->end())); 695 print_object(log.error_stream(), obj); 696 } 697 log.error("----------"); 698 _failures = true; 699 failed = true; 700 _n_failures++; 701 } 702 } 703 } 704 }; 705 706 class VerifyRemSetClosure : public G1VerificationClosure { 707 public: 708 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {} 709 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 710 virtual void do_oop(oop* p) { do_oop_work(p); } 711 712 template <class T> 713 void do_oop_work(T* p) { 714 assert(_containing_obj != NULL, "Precondition"); 715 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo), 716 "Precondition"); 717 verify_remembered_set(p); 718 } 719 720 template <class T> 721 void verify_remembered_set(T* p) { 722 T heap_oop = oopDesc::load_heap_oop(p); 723 Log(gc, verify) log; 724 if (!oopDesc::is_null(heap_oop)) { 725 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop); 726 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p); 727 HeapRegion* to = _g1h->heap_region_containing(obj); 728 if (from != NULL && to != NULL && 729 from != to && 730 !to->is_pinned()) { 731 jbyte cv_obj = *_ct->byte_for_const(_containing_obj); 732 jbyte cv_field = *_ct->byte_for_const(p); 733 const jbyte dirty = G1CardTable::dirty_card_val(); 734 735 bool is_bad = !(from->is_young() 736 || to->rem_set()->contains_reference(p) 737 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed 738 (_containing_obj->is_objArray() ? 739 cv_field == dirty 740 : cv_obj == dirty || cv_field == dirty)); 741 if (is_bad) { 742 MutexLockerEx x(ParGCRareEvent_lock, 743 Mutex::_no_safepoint_check_flag); 744 745 if (!_failures) { 746 log.error("----------"); 747 } 748 log.error("Missing rem set entry:"); 749 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT, 750 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from)); 751 ResourceMark rm; 752 _containing_obj->print_on(log.error_stream()); 753 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to)); 754 if (obj->is_oop()) { 755 obj->print_on(log.error_stream()); 756 } 757 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field); 758 log.error("----------"); 759 _failures = true; 760 _n_failures++; 761 } 762 } 763 } 764 } 765 }; 766 767 // Closure that applies the given two closures in sequence. 768 class G1Mux2Closure : public OopClosure { 769 OopClosure* _c1; 770 OopClosure* _c2; 771 public: 772 G1Mux2Closure(OopClosure *c1, OopClosure *c2) { _c1 = c1; _c2 = c2; } 773 template <class T> inline void do_oop_work(T* p) { 774 // Apply first closure; then apply the second. 775 _c1->do_oop(p); 776 _c2->do_oop(p); 777 } 778 virtual inline void do_oop(oop* p) { do_oop_work(p); } 779 virtual inline void do_oop(narrowOop* p) { do_oop_work(p); } 780 }; 781 782 // This really ought to be commoned up into OffsetTableContigSpace somehow. 783 // We would need a mechanism to make that code skip dead objects. 784 785 void HeapRegion::verify(VerifyOption vo, 786 bool* failures) const { 787 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 788 *failures = false; 789 HeapWord* p = bottom(); 790 HeapWord* prev_p = NULL; 791 VerifyLiveClosure vl_cl(g1, vo); 792 VerifyRemSetClosure vr_cl(g1, vo); 793 bool is_region_humongous = is_humongous(); 794 size_t object_num = 0; 795 while (p < top()) { 796 oop obj = oop(p); 797 size_t obj_size = block_size(p); 798 object_num += 1; 799 800 if (!g1->is_obj_dead_cond(obj, this, vo)) { 801 if (obj->is_oop()) { 802 Klass* klass = obj->klass(); 803 bool is_metaspace_object = Metaspace::contains(klass) || 804 (vo == VerifyOption_G1UsePrevMarking && 805 ClassLoaderDataGraph::unload_list_contains(klass)); 806 if (!is_metaspace_object) { 807 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 808 "not metadata", p2i(klass), p2i(obj)); 809 *failures = true; 810 return; 811 } else if (!klass->is_klass()) { 812 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " " 813 "not a klass", p2i(klass), p2i(obj)); 814 *failures = true; 815 return; 816 } else { 817 vl_cl.set_containing_obj(obj); 818 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) { 819 // verify liveness and rem_set 820 vr_cl.set_containing_obj(obj); 821 G1Mux2Closure mux(&vl_cl, &vr_cl); 822 obj->oop_iterate_no_header(&mux); 823 824 if (vr_cl.failures()) { 825 *failures = true; 826 } 827 if (G1MaxVerifyFailures >= 0 && 828 vr_cl.n_failures() >= G1MaxVerifyFailures) { 829 return; 830 } 831 } else { 832 // verify only liveness 833 obj->oop_iterate_no_header(&vl_cl); 834 } 835 if (vl_cl.failures()) { 836 *failures = true; 837 } 838 if (G1MaxVerifyFailures >= 0 && 839 vl_cl.n_failures() >= G1MaxVerifyFailures) { 840 return; 841 } 842 } 843 } else { 844 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 845 *failures = true; 846 return; 847 } 848 } 849 prev_p = p; 850 p += obj_size; 851 } 852 853 if (!is_young() && !is_empty()) { 854 _bot_part.verify(); 855 } 856 857 if (is_region_humongous) { 858 oop obj = oop(this->humongous_start_region()->bottom()); 859 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) { 860 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj)); 861 *failures = true; 862 return; 863 } 864 } 865 866 if (!is_region_humongous && p != top()) { 867 log_error(gc, verify)("end of last object " PTR_FORMAT " " 868 "does not match top " PTR_FORMAT, p2i(p), p2i(top())); 869 *failures = true; 870 return; 871 } 872 873 HeapWord* the_end = end(); 874 // Do some extra BOT consistency checking for addresses in the 875 // range [top, end). BOT look-ups in this range should yield 876 // top. No point in doing that if top == end (there's nothing there). 877 if (p < the_end) { 878 // Look up top 879 HeapWord* addr_1 = p; 880 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1); 881 if (b_start_1 != p) { 882 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " " 883 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 884 p2i(addr_1), p2i(b_start_1), p2i(p)); 885 *failures = true; 886 return; 887 } 888 889 // Look up top + 1 890 HeapWord* addr_2 = p + 1; 891 if (addr_2 < the_end) { 892 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2); 893 if (b_start_2 != p) { 894 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " " 895 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 896 p2i(addr_2), p2i(b_start_2), p2i(p)); 897 *failures = true; 898 return; 899 } 900 } 901 902 // Look up an address between top and end 903 size_t diff = pointer_delta(the_end, p) / 2; 904 HeapWord* addr_3 = p + diff; 905 if (addr_3 < the_end) { 906 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3); 907 if (b_start_3 != p) { 908 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " " 909 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 910 p2i(addr_3), p2i(b_start_3), p2i(p)); 911 *failures = true; 912 return; 913 } 914 } 915 916 // Look up end - 1 917 HeapWord* addr_4 = the_end - 1; 918 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4); 919 if (b_start_4 != p) { 920 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " " 921 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT, 922 p2i(addr_4), p2i(b_start_4), p2i(p)); 923 *failures = true; 924 return; 925 } 926 } 927 928 verify_strong_code_roots(vo, failures); 929 } 930 931 void HeapRegion::verify() const { 932 bool dummy = false; 933 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy); 934 } 935 936 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const { 937 G1CollectedHeap* g1 = G1CollectedHeap::heap(); 938 *failures = false; 939 HeapWord* p = bottom(); 940 HeapWord* prev_p = NULL; 941 VerifyRemSetClosure vr_cl(g1, vo); 942 while (p < top()) { 943 oop obj = oop(p); 944 size_t obj_size = block_size(p); 945 946 if (!g1->is_obj_dead_cond(obj, this, vo)) { 947 if (obj->is_oop()) { 948 vr_cl.set_containing_obj(obj); 949 obj->oop_iterate_no_header(&vr_cl); 950 951 if (vr_cl.failures()) { 952 *failures = true; 953 } 954 if (G1MaxVerifyFailures >= 0 && 955 vr_cl.n_failures() >= G1MaxVerifyFailures) { 956 return; 957 } 958 } else { 959 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj)); 960 *failures = true; 961 return; 962 } 963 } 964 965 prev_p = p; 966 p += obj_size; 967 } 968 } 969 970 void HeapRegion::verify_rem_set() const { 971 bool failures = false; 972 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures); 973 guarantee(!failures, "HeapRegion RemSet verification failed"); 974 } 975 976 void HeapRegion::prepare_for_compaction(CompactPoint* cp) { 977 scan_and_forward(this, cp); 978 } 979 980 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go 981 // away eventually. 982 983 void G1ContiguousSpace::clear(bool mangle_space) { 984 set_top(bottom()); 985 _scan_top = bottom(); 986 CompactibleSpace::clear(mangle_space); 987 reset_bot(); 988 } 989 990 #ifndef PRODUCT 991 void G1ContiguousSpace::mangle_unused_area() { 992 mangle_unused_area_complete(); 993 } 994 995 void G1ContiguousSpace::mangle_unused_area_complete() { 996 SpaceMangler::mangle_region(MemRegion(top(), end())); 997 } 998 #endif 999 1000 void G1ContiguousSpace::print() const { 1001 print_short(); 1002 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " 1003 INTPTR_FORMAT ", " INTPTR_FORMAT ")", 1004 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end())); 1005 } 1006 1007 HeapWord* G1ContiguousSpace::initialize_threshold() { 1008 return _bot_part.initialize_threshold(); 1009 } 1010 1011 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start, 1012 HeapWord* end) { 1013 _bot_part.alloc_block(start, end); 1014 return _bot_part.threshold(); 1015 } 1016 1017 HeapWord* G1ContiguousSpace::scan_top() const { 1018 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1019 HeapWord* local_top = top(); 1020 OrderAccess::loadload(); 1021 const unsigned local_time_stamp = _gc_time_stamp; 1022 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant"); 1023 if (local_time_stamp < g1h->get_gc_time_stamp()) { 1024 return local_top; 1025 } else { 1026 return _scan_top; 1027 } 1028 } 1029 1030 void G1ContiguousSpace::record_timestamp() { 1031 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 1032 uint curr_gc_time_stamp = g1h->get_gc_time_stamp(); 1033 1034 if (_gc_time_stamp < curr_gc_time_stamp) { 1035 // Setting the time stamp here tells concurrent readers to look at 1036 // scan_top to know the maximum allowed address to look at. 1037 1038 // scan_top should be bottom for all regions except for the 1039 // retained old alloc region which should have scan_top == top 1040 HeapWord* st = _scan_top; 1041 guarantee(st == _bottom || st == _top, "invariant"); 1042 1043 _gc_time_stamp = curr_gc_time_stamp; 1044 } 1045 } 1046 1047 void G1ContiguousSpace::record_retained_region() { 1048 // scan_top is the maximum address where it's safe for the next gc to 1049 // scan this region. 1050 _scan_top = top(); 1051 } 1052 1053 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { 1054 object_iterate(blk); 1055 } 1056 1057 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) { 1058 HeapWord* p = bottom(); 1059 while (p < top()) { 1060 if (block_is_obj(p)) { 1061 blk->do_object(oop(p)); 1062 } 1063 p += block_size(p); 1064 } 1065 } 1066 1067 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) : 1068 _bot_part(bot, this), 1069 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true), 1070 _gc_time_stamp(0) 1071 { 1072 } 1073 1074 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) { 1075 CompactibleSpace::initialize(mr, clear_space, mangle_space); 1076 _top = bottom(); 1077 _scan_top = bottom(); 1078 set_saved_mark_word(NULL); 1079 reset_bot(); 1080 }