1 /*
   2  * Copyright (c) 2001, 2019, 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/g1CollectionSet.hpp"
  30 #include "gc/g1/g1HeapRegionTraceType.hpp"
  31 #include "gc/g1/g1OopClosures.inline.hpp"
  32 #include "gc/g1/heapRegion.inline.hpp"
  33 #include "gc/g1/heapRegionBounds.inline.hpp"
  34 #include "gc/g1/heapRegionManager.inline.hpp"
  35 #include "gc/g1/heapRegionRemSet.hpp"
  36 #include "gc/g1/heapRegionTracer.hpp"
  37 #include "gc/shared/genOopClosures.inline.hpp"
  38 #include "gc/shared/space.inline.hpp"
  39 #include "logging/log.hpp"
  40 #include "logging/logStream.hpp"
  41 #include "memory/iterator.inline.hpp"
  42 #include "memory/resourceArea.hpp"
  43 #include "oops/access.inline.hpp"
  44 #include "oops/compressedOops.inline.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "runtime/atomic.hpp"
  47 #include "runtime/orderAccess.hpp"
  48 #include "utilities/growableArray.hpp"
  49 
  50 int    HeapRegion::LogOfHRGrainBytes = 0;
  51 int    HeapRegion::LogOfHRGrainWords = 0;
  52 size_t HeapRegion::GrainBytes        = 0;
  53 size_t HeapRegion::GrainWords        = 0;
  54 size_t HeapRegion::CardsPerRegion    = 0;
  55 
  56 size_t HeapRegion::max_region_size() {
  57   return HeapRegionBounds::max_size();
  58 }
  59 
  60 size_t HeapRegion::min_region_size_in_words() {
  61   return HeapRegionBounds::min_size() >> LogHeapWordSize;
  62 }
  63 
  64 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
  65   size_t region_size = G1HeapRegionSize;
  66   if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
  67     size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
  68     region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
  69                        HeapRegionBounds::min_size());
  70   }
  71 
  72   int region_size_log = log2_long((jlong) region_size);
  73   // Recalculate the region size to make sure it's a power of
  74   // 2. This means that region_size is the largest power of 2 that's
  75   // <= what we've calculated so far.
  76   region_size = ((size_t)1 << region_size_log);
  77 
  78   // Now make sure that we don't go over or under our limits.
  79   if (region_size < HeapRegionBounds::min_size()) {
  80     region_size = HeapRegionBounds::min_size();
  81   } else if (region_size > HeapRegionBounds::max_size()) {
  82     region_size = HeapRegionBounds::max_size();
  83   }
  84 
  85   // And recalculate the log.
  86   region_size_log = log2_long((jlong) region_size);
  87 
  88   // Now, set up the globals.
  89   guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
  90   LogOfHRGrainBytes = region_size_log;
  91 
  92   guarantee(LogOfHRGrainWords == 0, "we should only set it once");
  93   LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
  94 
  95   guarantee(GrainBytes == 0, "we should only set it once");
  96   // The cast to int is safe, given that we've bounded region_size by
  97   // MIN_REGION_SIZE and MAX_REGION_SIZE.
  98   GrainBytes = region_size;
  99   log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M);
 100 
 101   guarantee(GrainWords == 0, "we should only set it once");
 102   GrainWords = GrainBytes >> LogHeapWordSize;
 103   guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
 104 
 105   guarantee(CardsPerRegion == 0, "we should only set it once");
 106   CardsPerRegion = GrainBytes >> G1CardTable::card_shift;
 107 
 108   if (G1HeapRegionSize != GrainBytes) {
 109     FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes);
 110   }
 111 }
 112 
 113 void HeapRegion::hr_clear(bool keep_remset, bool clear_space, bool locked) {
 114   assert(_humongous_start_region == NULL,
 115          "we should have already filtered out humongous regions");
 116   assert(!in_collection_set(),
 117          "Should not clear heap region %u in the collection set", hrm_index());
 118 
 119   set_young_index_in_cset(-1);
 120   uninstall_surv_rate_group();
 121   set_free();
 122   reset_pre_dummy_top();
 123 
 124   if (!keep_remset) {
 125     if (locked) {
 126       rem_set()->clear_locked();
 127     } else {
 128       rem_set()->clear();
 129     }
 130   }
 131 
 132   zero_marked_bytes();
 133 
 134   init_top_at_mark_start();
 135   if (clear_space) clear(SpaceDecorator::Mangle);
 136 }
 137 
 138 void HeapRegion::clear_cardtable() {
 139   G1CardTable* ct = G1CollectedHeap::heap()->card_table();
 140   ct->clear(MemRegion(bottom(), end()));
 141 }
 142 
 143 void HeapRegion::calc_gc_efficiency() {
 144   // GC efficiency is the ratio of how much space would be
 145   // reclaimed over how long we predict it would take to reclaim it.
 146   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 147   G1Policy* policy = g1h->policy();
 148 
 149   // Retrieve a prediction of the elapsed time for this region for
 150   // a mixed gc because the region will only be evacuated during a
 151   // mixed gc.
 152   double region_elapsed_time_ms =
 153     policy->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
 154   _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
 155 }
 156 
 157 void HeapRegion::set_free() {
 158   report_region_type_change(G1HeapRegionTraceType::Free);
 159   _type.set_free();
 160 }
 161 
 162 void HeapRegion::set_eden() {
 163   report_region_type_change(G1HeapRegionTraceType::Eden);
 164   _type.set_eden();
 165 }
 166 
 167 void HeapRegion::set_eden_pre_gc() {
 168   report_region_type_change(G1HeapRegionTraceType::Eden);
 169   _type.set_eden_pre_gc();
 170 }
 171 
 172 void HeapRegion::set_survivor() {
 173   report_region_type_change(G1HeapRegionTraceType::Survivor);
 174   _type.set_survivor();
 175 }
 176 
 177 void HeapRegion::move_to_old() {
 178   if (_type.relabel_as_old()) {
 179     report_region_type_change(G1HeapRegionTraceType::Old);
 180   }
 181 }
 182 
 183 void HeapRegion::set_old() {
 184   report_region_type_change(G1HeapRegionTraceType::Old);
 185   _type.set_old();
 186 }
 187 
 188 void HeapRegion::set_open_archive() {
 189   report_region_type_change(G1HeapRegionTraceType::OpenArchive);
 190   _type.set_open_archive();
 191 }
 192 
 193 void HeapRegion::set_closed_archive() {
 194   report_region_type_change(G1HeapRegionTraceType::ClosedArchive);
 195   _type.set_closed_archive();
 196 }
 197 
 198 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
 199   assert(!is_humongous(), "sanity / pre-condition");
 200   assert(top() == bottom(), "should be empty");
 201 
 202   report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
 203   _type.set_starts_humongous();
 204   _humongous_start_region = this;
 205 
 206   _bot_part.set_for_starts_humongous(obj_top, fill_size);
 207 }
 208 
 209 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
 210   assert(!is_humongous(), "sanity / pre-condition");
 211   assert(top() == bottom(), "should be empty");
 212   assert(first_hr->is_starts_humongous(), "pre-condition");
 213 
 214   report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
 215   _type.set_continues_humongous();
 216   _humongous_start_region = first_hr;
 217 
 218   _bot_part.set_object_can_span(true);
 219 }
 220 
 221 void HeapRegion::clear_humongous() {
 222   assert(is_humongous(), "pre-condition");
 223 
 224   assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
 225   _humongous_start_region = NULL;
 226 
 227   _bot_part.set_object_can_span(false);
 228 }
 229 
 230 HeapRegion::HeapRegion(uint hrm_index,
 231                        G1BlockOffsetTable* bot,
 232                        MemRegion mr) :
 233     G1ContiguousSpace(bot),
 234     _rem_set(NULL),
 235     _hrm_index(hrm_index),
 236     _type(),
 237     _humongous_start_region(NULL),
 238     _evacuation_failed(false),
 239     _next(NULL), _prev(NULL),
 240 #ifdef ASSERT
 241     _containing_set(NULL),
 242 #endif
 243     _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
 244     _index_in_opt_cset(G1OptionalCSet::InvalidCSetIndex), _young_index_in_cset(-1),
 245     _surv_rate_group(NULL), _age_index(-1),
 246     _prev_top_at_mark_start(NULL), _next_top_at_mark_start(NULL),
 247     _recorded_rs_length(0), _predicted_elapsed_time_ms(0)
 248 {
 249   _rem_set = new HeapRegionRemSet(bot, this);
 250 
 251   initialize(mr);
 252 }
 253 
 254 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
 255   assert(_rem_set->is_empty(), "Remembered set must be empty");
 256 
 257   G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
 258 
 259   hr_clear(false /*par*/, false /*clear_space*/);
 260   set_top(bottom());
 261 }
 262 
 263 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
 264   HeapRegionTracer::send_region_type_change(_hrm_index,
 265                                             get_trace_type(),
 266                                             to,
 267                                             (uintptr_t)bottom(),
 268                                             used());
 269 }
 270 
 271 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
 272                                                     bool during_conc_mark) {
 273   // We always recreate the prev marking info and we'll explicitly
 274   // mark all objects we find to be self-forwarded on the prev
 275   // bitmap. So all objects need to be below PTAMS.
 276   _prev_marked_bytes = 0;
 277 
 278   if (during_initial_mark) {
 279     // During initial-mark, we'll also explicitly mark all objects
 280     // we find to be self-forwarded on the next bitmap. So all
 281     // objects need to be below NTAMS.
 282     _next_top_at_mark_start = top();
 283     _next_marked_bytes = 0;
 284   } else if (during_conc_mark) {
 285     // During concurrent mark, all objects in the CSet (including
 286     // the ones we find to be self-forwarded) are implicitly live.
 287     // So all objects need to be above NTAMS.
 288     _next_top_at_mark_start = bottom();
 289     _next_marked_bytes = 0;
 290   }
 291 }
 292 
 293 void HeapRegion::note_self_forwarding_removal_end(size_t marked_bytes) {
 294   assert(marked_bytes <= used(),
 295          "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
 296   _prev_top_at_mark_start = top();
 297   _prev_marked_bytes = marked_bytes;
 298 }
 299 
 300 // Code roots support
 301 
 302 void HeapRegion::add_strong_code_root(nmethod* nm) {
 303   HeapRegionRemSet* hrrs = rem_set();
 304   hrrs->add_strong_code_root(nm);
 305 }
 306 
 307 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
 308   assert_locked_or_safepoint(CodeCache_lock);
 309   HeapRegionRemSet* hrrs = rem_set();
 310   hrrs->add_strong_code_root_locked(nm);
 311 }
 312 
 313 void HeapRegion::remove_strong_code_root(nmethod* nm) {
 314   HeapRegionRemSet* hrrs = rem_set();
 315   hrrs->remove_strong_code_root(nm);
 316 }
 317 
 318 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
 319   HeapRegionRemSet* hrrs = rem_set();
 320   hrrs->strong_code_roots_do(blk);
 321 }
 322 
 323 class VerifyStrongCodeRootOopClosure: public OopClosure {
 324   const HeapRegion* _hr;
 325   bool _failures;
 326   bool _has_oops_in_region;
 327 
 328   template <class T> void do_oop_work(T* p) {
 329     T heap_oop = RawAccess<>::oop_load(p);
 330     if (!CompressedOops::is_null(heap_oop)) {
 331       oop obj = CompressedOops::decode_not_null(heap_oop);
 332 
 333       // Note: not all the oops embedded in the nmethod are in the
 334       // current region. We only look at those which are.
 335       if (_hr->is_in(obj)) {
 336         // Object is in the region. Check that its less than top
 337         if (_hr->top() <= (HeapWord*)obj) {
 338           // Object is above top
 339           log_error(gc, verify)("Object " PTR_FORMAT " in region " HR_FORMAT " is above top ",
 340                                 p2i(obj), HR_FORMAT_PARAMS(_hr));
 341           _failures = true;
 342           return;
 343         }
 344         // Nmethod has at least one oop in the current region
 345         _has_oops_in_region = true;
 346       }
 347     }
 348   }
 349 
 350 public:
 351   VerifyStrongCodeRootOopClosure(const HeapRegion* hr):
 352     _hr(hr), _failures(false), _has_oops_in_region(false) {}
 353 
 354   void do_oop(narrowOop* p) { do_oop_work(p); }
 355   void do_oop(oop* p)       { do_oop_work(p); }
 356 
 357   bool failures()           { return _failures; }
 358   bool has_oops_in_region() { return _has_oops_in_region; }
 359 };
 360 
 361 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
 362   const HeapRegion* _hr;
 363   bool _failures;
 364 public:
 365   VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
 366     _hr(hr), _failures(false) {}
 367 
 368   void do_code_blob(CodeBlob* cb) {
 369     nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null();
 370     if (nm != NULL) {
 371       // Verify that the nemthod is live
 372       if (!nm->is_alive()) {
 373         log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
 374                               p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 375         _failures = true;
 376       } else {
 377         VerifyStrongCodeRootOopClosure oop_cl(_hr);
 378         nm->oops_do(&oop_cl);
 379         if (!oop_cl.has_oops_in_region()) {
 380           log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
 381                                 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 382           _failures = true;
 383         } else if (oop_cl.failures()) {
 384           log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
 385                                 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 386           _failures = true;
 387         }
 388       }
 389     }
 390   }
 391 
 392   bool failures()       { return _failures; }
 393 };
 394 
 395 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
 396   if (!G1VerifyHeapRegionCodeRoots) {
 397     // We're not verifying code roots.
 398     return;
 399   }
 400   if (vo == VerifyOption_G1UseFullMarking) {
 401     // Marking verification during a full GC is performed after class
 402     // unloading, code cache unloading, etc so the strong code roots
 403     // attached to each heap region are in an inconsistent state. They won't
 404     // be consistent until the strong code roots are rebuilt after the
 405     // actual GC. Skip verifying the strong code roots in this particular
 406     // time.
 407     assert(VerifyDuringGC, "only way to get here");
 408     return;
 409   }
 410 
 411   HeapRegionRemSet* hrrs = rem_set();
 412   size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
 413 
 414   // if this region is empty then there should be no entries
 415   // on its strong code root list
 416   if (is_empty()) {
 417     if (strong_code_roots_length > 0) {
 418       log_error(gc, verify)("region " HR_FORMAT " is empty but has " SIZE_FORMAT " code root entries",
 419                             HR_FORMAT_PARAMS(this), strong_code_roots_length);
 420       *failures = true;
 421     }
 422     return;
 423   }
 424 
 425   if (is_continues_humongous()) {
 426     if (strong_code_roots_length > 0) {
 427       log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
 428                             HR_FORMAT_PARAMS(this), strong_code_roots_length);
 429       *failures = true;
 430     }
 431     return;
 432   }
 433 
 434   VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
 435   strong_code_roots_do(&cb_cl);
 436 
 437   if (cb_cl.failures()) {
 438     *failures = true;
 439   }
 440 }
 441 
 442 void HeapRegion::print() const { print_on(tty); }
 443 void HeapRegion::print_on(outputStream* st) const {
 444   st->print("|%4u", this->_hrm_index);
 445   st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
 446             p2i(bottom()), p2i(top()), p2i(end()));
 447   st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
 448   st->print("|%2s", get_short_type_str());
 449   if (in_collection_set()) {
 450     st->print("|CS");
 451   } else {
 452     st->print("|  ");
 453   }
 454   st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "| %s ",
 455                p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()), rem_set()->get_state_str());
 456 }
 457 
 458 class G1VerificationClosure : public BasicOopIterateClosure {
 459 protected:
 460   G1CollectedHeap* _g1h;
 461   G1CardTable *_ct;
 462   oop _containing_obj;
 463   bool _failures;
 464   int _n_failures;
 465   VerifyOption _vo;
 466 public:
 467   // _vo == UsePrevMarking -> use "prev" marking information,
 468   // _vo == UseNextMarking -> use "next" marking information,
 469   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS.
 470   G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
 471     _g1h(g1h), _ct(g1h->card_table()),
 472     _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
 473   }
 474 
 475   void set_containing_obj(oop obj) {
 476     _containing_obj = obj;
 477   }
 478 
 479   bool failures() { return _failures; }
 480   int n_failures() { return _n_failures; }
 481 
 482   void print_object(outputStream* out, oop obj) {
 483 #ifdef PRODUCT
 484     Klass* k = obj->klass();
 485     const char* class_name = k->external_name();
 486     out->print_cr("class name %s", class_name);
 487 #else // PRODUCT
 488     obj->print_on(out);
 489 #endif // PRODUCT
 490   }
 491 
 492   // This closure provides its own oop verification code.
 493   debug_only(virtual bool should_verify_oops() { return false; })
 494 };
 495 
 496 class VerifyLiveClosure : public G1VerificationClosure {
 497 public:
 498   VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
 499   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
 500   virtual void do_oop(oop* p) { do_oop_work(p); }
 501 
 502   template <class T>
 503   void do_oop_work(T* p) {
 504     assert(_containing_obj != NULL, "Precondition");
 505     assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
 506       "Precondition");
 507     verify_liveness(p);
 508   }
 509 
 510   template <class T>
 511   void verify_liveness(T* p) {
 512     T heap_oop = RawAccess<>::oop_load(p);
 513     Log(gc, verify) log;
 514     if (!CompressedOops::is_null(heap_oop)) {
 515       oop obj = CompressedOops::decode_not_null(heap_oop);
 516       bool failed = false;
 517       if (!_g1h->is_in(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
 518         MutexLockerEx x(ParGCRareEvent_lock,
 519           Mutex::_no_safepoint_check_flag);
 520 
 521         if (!_failures) {
 522           log.error("----------");
 523         }
 524         ResourceMark rm;
 525         if (!_g1h->is_in(obj)) {
 526           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 527           log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region " HR_FORMAT,
 528                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 529           LogStream ls(log.error());
 530           print_object(&ls, _containing_obj);
 531           HeapRegion* const to = _g1h->heap_region_containing(obj);
 532           log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT " remset %s",
 533                     p2i(obj), HR_FORMAT_PARAMS(to), to->rem_set()->get_state_str());
 534         } else {
 535           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 536           HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
 537           log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region " HR_FORMAT,
 538                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 539           LogStream ls(log.error());
 540           print_object(&ls, _containing_obj);
 541           log.error("points to dead obj " PTR_FORMAT " in region " HR_FORMAT,
 542                     p2i(obj), HR_FORMAT_PARAMS(to));
 543           print_object(&ls, obj);
 544         }
 545         log.error("----------");
 546         _failures = true;
 547         failed = true;
 548         _n_failures++;
 549       }
 550     }
 551   }
 552 };
 553 
 554 class VerifyRemSetClosure : public G1VerificationClosure {
 555 public:
 556   VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
 557   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
 558   virtual void do_oop(oop* p) { do_oop_work(p); }
 559 
 560   template <class T>
 561   void do_oop_work(T* p) {
 562     assert(_containing_obj != NULL, "Precondition");
 563     assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
 564       "Precondition");
 565     verify_remembered_set(p);
 566   }
 567 
 568   template <class T>
 569   void verify_remembered_set(T* p) {
 570     T heap_oop = RawAccess<>::oop_load(p);
 571     Log(gc, verify) log;
 572     if (!CompressedOops::is_null(heap_oop)) {
 573       oop obj = CompressedOops::decode_not_null(heap_oop);
 574       HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 575       HeapRegion* to = _g1h->heap_region_containing(obj);
 576       if (from != NULL && to != NULL &&
 577         from != to &&
 578         !to->is_pinned() &&
 579         to->rem_set()->is_complete()) {
 580         jbyte cv_obj = *_ct->byte_for_const(_containing_obj);
 581         jbyte cv_field = *_ct->byte_for_const(p);
 582         const jbyte dirty = G1CardTable::dirty_card_val();
 583 
 584         bool is_bad = !(from->is_young()
 585           || to->rem_set()->contains_reference(p)
 586           || (_containing_obj->is_objArray() ?
 587                 cv_field == dirty :
 588                 cv_obj == dirty || cv_field == dirty));
 589         if (is_bad) {
 590           MutexLockerEx x(ParGCRareEvent_lock,
 591             Mutex::_no_safepoint_check_flag);
 592 
 593           if (!_failures) {
 594             log.error("----------");
 595           }
 596           log.error("Missing rem set entry:");
 597           log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT " in region " HR_FORMAT,
 598                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 599           ResourceMark rm;
 600           LogStream ls(log.error());
 601           _containing_obj->print_on(&ls);
 602           log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT " remset %s",
 603                     p2i(obj), HR_FORMAT_PARAMS(to), to->rem_set()->get_state_str());
 604           if (oopDesc::is_oop(obj)) {
 605             obj->print_on(&ls);
 606           }
 607           log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
 608           log.error("----------");
 609           _failures = true;
 610           _n_failures++;
 611         }
 612       }
 613     }
 614   }
 615 };
 616 
 617 // Closure that applies the given two closures in sequence.
 618 class G1Mux2Closure : public BasicOopIterateClosure {
 619   OopClosure* _c1;
 620   OopClosure* _c2;
 621 public:
 622   G1Mux2Closure(OopClosure *c1, OopClosure *c2) { _c1 = c1; _c2 = c2; }
 623   template <class T> inline void do_oop_work(T* p) {
 624     // Apply first closure; then apply the second.
 625     _c1->do_oop(p);
 626     _c2->do_oop(p);
 627   }
 628   virtual inline void do_oop(oop* p) { do_oop_work(p); }
 629   virtual inline void do_oop(narrowOop* p) { do_oop_work(p); }
 630 
 631   // This closure provides its own oop verification code.
 632   debug_only(virtual bool should_verify_oops() { return false; })
 633 };
 634 
 635 // This really ought to be commoned up into OffsetTableContigSpace somehow.
 636 // We would need a mechanism to make that code skip dead objects.
 637 
 638 void HeapRegion::verify(VerifyOption vo,
 639                         bool* failures) const {
 640   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 641   *failures = false;
 642   HeapWord* p = bottom();
 643   HeapWord* prev_p = NULL;
 644   VerifyLiveClosure vl_cl(g1h, vo);
 645   VerifyRemSetClosure vr_cl(g1h, vo);
 646   bool is_region_humongous = is_humongous();
 647   size_t object_num = 0;
 648   while (p < top()) {
 649     oop obj = oop(p);
 650     size_t obj_size = block_size(p);
 651     object_num += 1;
 652 
 653     if (!g1h->is_obj_dead_cond(obj, this, vo)) {
 654       if (oopDesc::is_oop(obj)) {
 655         Klass* klass = obj->klass();
 656         bool is_metaspace_object = Metaspace::contains(klass);
 657         if (!is_metaspace_object) {
 658           log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
 659                                 "not metadata", p2i(klass), p2i(obj));
 660           *failures = true;
 661           return;
 662         } else if (!klass->is_klass()) {
 663           log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
 664                                 "not a klass", p2i(klass), p2i(obj));
 665           *failures = true;
 666           return;
 667         } else {
 668           vl_cl.set_containing_obj(obj);
 669           if (!g1h->collector_state()->in_full_gc() || G1VerifyRSetsDuringFullGC) {
 670             // verify liveness and rem_set
 671             vr_cl.set_containing_obj(obj);
 672             G1Mux2Closure mux(&vl_cl, &vr_cl);
 673             obj->oop_iterate(&mux);
 674 
 675             if (vr_cl.failures()) {
 676               *failures = true;
 677             }
 678             if (G1MaxVerifyFailures >= 0 &&
 679               vr_cl.n_failures() >= G1MaxVerifyFailures) {
 680               return;
 681             }
 682           } else {
 683             // verify only liveness
 684             obj->oop_iterate(&vl_cl);
 685           }
 686           if (vl_cl.failures()) {
 687             *failures = true;
 688           }
 689           if (G1MaxVerifyFailures >= 0 &&
 690               vl_cl.n_failures() >= G1MaxVerifyFailures) {
 691             return;
 692           }
 693         }
 694       } else {
 695         log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
 696         *failures = true;
 697         return;
 698       }
 699     }
 700     prev_p = p;
 701     p += obj_size;
 702   }
 703 
 704   if (!is_young() && !is_empty()) {
 705     _bot_part.verify();
 706   }
 707 
 708   if (is_region_humongous) {
 709     oop obj = oop(this->humongous_start_region()->bottom());
 710     if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
 711       log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
 712       *failures = true;
 713       return;
 714     }
 715   }
 716 
 717   if (!is_region_humongous && p != top()) {
 718     log_error(gc, verify)("end of last object " PTR_FORMAT " "
 719                           "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
 720     *failures = true;
 721     return;
 722   }
 723 
 724   HeapWord* the_end = end();
 725   // Do some extra BOT consistency checking for addresses in the
 726   // range [top, end). BOT look-ups in this range should yield
 727   // top. No point in doing that if top == end (there's nothing there).
 728   if (p < the_end) {
 729     // Look up top
 730     HeapWord* addr_1 = p;
 731     HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
 732     if (b_start_1 != p) {
 733       log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
 734                             " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 735                             p2i(addr_1), p2i(b_start_1), p2i(p));
 736       *failures = true;
 737       return;
 738     }
 739 
 740     // Look up top + 1
 741     HeapWord* addr_2 = p + 1;
 742     if (addr_2 < the_end) {
 743       HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
 744       if (b_start_2 != p) {
 745         log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
 746                               " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 747                               p2i(addr_2), p2i(b_start_2), p2i(p));
 748         *failures = true;
 749         return;
 750       }
 751     }
 752 
 753     // Look up an address between top and end
 754     size_t diff = pointer_delta(the_end, p) / 2;
 755     HeapWord* addr_3 = p + diff;
 756     if (addr_3 < the_end) {
 757       HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
 758       if (b_start_3 != p) {
 759         log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
 760                               " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 761                               p2i(addr_3), p2i(b_start_3), p2i(p));
 762         *failures = true;
 763         return;
 764       }
 765     }
 766 
 767     // Look up end - 1
 768     HeapWord* addr_4 = the_end - 1;
 769     HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
 770     if (b_start_4 != p) {
 771       log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
 772                             " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 773                             p2i(addr_4), p2i(b_start_4), p2i(p));
 774       *failures = true;
 775       return;
 776     }
 777   }
 778 
 779   verify_strong_code_roots(vo, failures);
 780 }
 781 
 782 void HeapRegion::verify() const {
 783   bool dummy = false;
 784   verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
 785 }
 786 
 787 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
 788   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 789   *failures = false;
 790   HeapWord* p = bottom();
 791   HeapWord* prev_p = NULL;
 792   VerifyRemSetClosure vr_cl(g1h, vo);
 793   while (p < top()) {
 794     oop obj = oop(p);
 795     size_t obj_size = block_size(p);
 796 
 797     if (!g1h->is_obj_dead_cond(obj, this, vo)) {
 798       if (oopDesc::is_oop(obj)) {
 799         vr_cl.set_containing_obj(obj);
 800         obj->oop_iterate(&vr_cl);
 801 
 802         if (vr_cl.failures()) {
 803           *failures = true;
 804         }
 805         if (G1MaxVerifyFailures >= 0 &&
 806           vr_cl.n_failures() >= G1MaxVerifyFailures) {
 807           return;
 808         }
 809       } else {
 810         log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
 811         *failures = true;
 812         return;
 813       }
 814     }
 815 
 816     prev_p = p;
 817     p += obj_size;
 818   }
 819 }
 820 
 821 void HeapRegion::verify_rem_set() const {
 822   bool failures = false;
 823   verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
 824   guarantee(!failures, "HeapRegion RemSet verification failed");
 825 }
 826 
 827 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
 828   // Not used for G1 anymore, but pure virtual in Space.
 829   ShouldNotReachHere();
 830 }
 831 
 832 // G1OffsetTableContigSpace code; copied from space.cpp.  Hope this can go
 833 // away eventually.
 834 
 835 void G1ContiguousSpace::clear(bool mangle_space) {
 836   set_top(bottom());
 837   CompactibleSpace::clear(mangle_space);
 838   reset_bot();
 839 }
 840 #ifndef PRODUCT
 841 void G1ContiguousSpace::mangle_unused_area() {
 842   mangle_unused_area_complete();
 843 }
 844 
 845 void G1ContiguousSpace::mangle_unused_area_complete() {
 846   SpaceMangler::mangle_region(MemRegion(top(), end()));
 847 }
 848 #endif
 849 
 850 void G1ContiguousSpace::print() const {
 851   print_short();
 852   tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
 853                 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
 854                 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
 855 }
 856 
 857 HeapWord* G1ContiguousSpace::initialize_threshold() {
 858   return _bot_part.initialize_threshold();
 859 }
 860 
 861 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
 862                                                     HeapWord* end) {
 863   _bot_part.alloc_block(start, end);
 864   return _bot_part.threshold();
 865 }
 866 
 867 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
 868   object_iterate(blk);
 869 }
 870 
 871 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
 872   HeapWord* p = bottom();
 873   while (p < top()) {
 874     if (block_is_obj(p)) {
 875       blk->do_object(oop(p));
 876     }
 877     p += block_size(p);
 878   }
 879 }
 880 
 881 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
 882   _top(NULL),
 883   _bot_part(bot, this),
 884   _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
 885   _pre_dummy_top(NULL)
 886 {
 887 }
 888 
 889 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
 890   CompactibleSpace::initialize(mr, clear_space, mangle_space);
 891   _top = bottom();
 892   set_saved_mark_word(NULL);
 893   reset_bot();
 894 }