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(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   clear_index_in_opt_cset();
 121   uninstall_surv_rate_group();
 122   set_free();
 123   reset_pre_dummy_top();
 124 
 125   if (!keep_remset) {
 126     if (locked) {
 127       rem_set()->clear_locked();
 128     } else {
 129       rem_set()->clear();
 130     }
 131   }
 132 
 133   zero_marked_bytes();
 134 
 135   init_top_at_mark_start();
 136   if (clear_space) clear(SpaceDecorator::Mangle);
 137 }
 138 
 139 void HeapRegion::clear_cardtable() {
 140   G1CardTable* ct = G1CollectedHeap::heap()->card_table();
 141   ct->clear(MemRegion(bottom(), end()));
 142 }
 143 
 144 void HeapRegion::calc_gc_efficiency() {
 145   // GC efficiency is the ratio of how much space would be
 146   // reclaimed over how long we predict it would take to reclaim it.
 147   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 148   G1Policy* policy = g1h->policy();
 149 
 150   // Retrieve a prediction of the elapsed time for this region for
 151   // a mixed gc because the region will only be evacuated during a
 152   // mixed gc.
 153   double region_elapsed_time_ms =
 154     policy->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
 155   _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
 156 }
 157 
 158 void HeapRegion::set_free() {
 159   report_region_type_change(G1HeapRegionTraceType::Free);
 160   _type.set_free();
 161 }
 162 
 163 void HeapRegion::set_eden() {
 164   report_region_type_change(G1HeapRegionTraceType::Eden);
 165   _type.set_eden();
 166 }
 167 
 168 void HeapRegion::set_eden_pre_gc() {
 169   report_region_type_change(G1HeapRegionTraceType::Eden);
 170   _type.set_eden_pre_gc();
 171 }
 172 
 173 void HeapRegion::set_survivor() {
 174   report_region_type_change(G1HeapRegionTraceType::Survivor);
 175   _type.set_survivor();
 176 }
 177 
 178 void HeapRegion::move_to_old() {
 179   if (_type.relabel_as_old()) {
 180     report_region_type_change(G1HeapRegionTraceType::Old);
 181   }
 182 }
 183 
 184 void HeapRegion::set_old() {
 185   report_region_type_change(G1HeapRegionTraceType::Old);
 186   _type.set_old();
 187 }
 188 
 189 void HeapRegion::set_open_archive() {
 190   report_region_type_change(G1HeapRegionTraceType::OpenArchive);
 191   _type.set_open_archive();
 192 }
 193 
 194 void HeapRegion::set_closed_archive() {
 195   report_region_type_change(G1HeapRegionTraceType::ClosedArchive);
 196   _type.set_closed_archive();
 197 }
 198 
 199 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
 200   assert(!is_humongous(), "sanity / pre-condition");
 201   assert(top() == bottom(), "should be empty");
 202 
 203   report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
 204   _type.set_starts_humongous();
 205   _humongous_start_region = this;
 206 
 207   _bot_part.set_for_starts_humongous(obj_top, fill_size);
 208 }
 209 
 210 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
 211   assert(!is_humongous(), "sanity / pre-condition");
 212   assert(top() == bottom(), "should be empty");
 213   assert(first_hr->is_starts_humongous(), "pre-condition");
 214 
 215   report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
 216   _type.set_continues_humongous();
 217   _humongous_start_region = first_hr;
 218 
 219   _bot_part.set_object_can_span(true);
 220 }
 221 
 222 void HeapRegion::clear_humongous() {
 223   assert(is_humongous(), "pre-condition");
 224 
 225   assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
 226   _humongous_start_region = NULL;
 227 
 228   _bot_part.set_object_can_span(false);
 229 }
 230 
 231 HeapRegion::HeapRegion(uint hrm_index,
 232                        G1BlockOffsetTable* bot,
 233                        MemRegion mr) :
 234     G1ContiguousSpace(bot),
 235     _rem_set(NULL),
 236     _hrm_index(hrm_index),
 237     _type(),
 238     _humongous_start_region(NULL),
 239     _evacuation_failed(false),
 240     _next(NULL), _prev(NULL),
 241 #ifdef ASSERT
 242     _containing_set(NULL),
 243 #endif
 244     _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
 245     _index_in_opt_cset(InvalidCSetIndex), _young_index_in_cset(-1),
 246     _surv_rate_group(NULL), _age_index(-1),
 247     _prev_top_at_mark_start(NULL), _next_top_at_mark_start(NULL),
 248     _recorded_rs_length(0), _predicted_elapsed_time_ms(0)
 249 {
 250   _rem_set = new HeapRegionRemSet(bot, this);
 251 
 252   initialize(mr);
 253 }
 254 
 255 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
 256   assert(_rem_set->is_empty(), "Remembered set must be empty");
 257 
 258   G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
 259 
 260   hr_clear(false /*par*/, false /*clear_space*/);
 261   set_top(bottom());
 262 }
 263 
 264 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
 265   HeapRegionTracer::send_region_type_change(_hrm_index,
 266                                             get_trace_type(),
 267                                             to,
 268                                             (uintptr_t)bottom(),
 269                                             used());
 270 }
 271 
 272 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
 273                                                     bool during_conc_mark) {
 274   // We always recreate the prev marking info and we'll explicitly
 275   // mark all objects we find to be self-forwarded on the prev
 276   // bitmap. So all objects need to be below PTAMS.
 277   _prev_marked_bytes = 0;
 278 
 279   if (during_initial_mark) {
 280     // During initial-mark, we'll also explicitly mark all objects
 281     // we find to be self-forwarded on the next bitmap. So all
 282     // objects need to be below NTAMS.
 283     _next_top_at_mark_start = top();
 284     _next_marked_bytes = 0;
 285   } else if (during_conc_mark) {
 286     // During concurrent mark, all objects in the CSet (including
 287     // the ones we find to be self-forwarded) are implicitly live.
 288     // So all objects need to be above NTAMS.
 289     _next_top_at_mark_start = bottom();
 290     _next_marked_bytes = 0;
 291   }
 292 }
 293 
 294 void HeapRegion::note_self_forwarding_removal_end(size_t marked_bytes) {
 295   assert(marked_bytes <= used(),
 296          "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
 297   _prev_top_at_mark_start = top();
 298   _prev_marked_bytes = marked_bytes;
 299 }
 300 
 301 // Code roots support
 302 
 303 void HeapRegion::add_strong_code_root(nmethod* nm) {
 304   HeapRegionRemSet* hrrs = rem_set();
 305   hrrs->add_strong_code_root(nm);
 306 }
 307 
 308 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
 309   assert_locked_or_safepoint(CodeCache_lock);
 310   HeapRegionRemSet* hrrs = rem_set();
 311   hrrs->add_strong_code_root_locked(nm);
 312 }
 313 
 314 void HeapRegion::remove_strong_code_root(nmethod* nm) {
 315   HeapRegionRemSet* hrrs = rem_set();
 316   hrrs->remove_strong_code_root(nm);
 317 }
 318 
 319 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
 320   HeapRegionRemSet* hrrs = rem_set();
 321   hrrs->strong_code_roots_do(blk);
 322 }
 323 
 324 class VerifyStrongCodeRootOopClosure: public OopClosure {
 325   const HeapRegion* _hr;
 326   bool _failures;
 327   bool _has_oops_in_region;
 328 
 329   template <class T> void do_oop_work(T* p) {
 330     T heap_oop = RawAccess<>::oop_load(p);
 331     if (!CompressedOops::is_null(heap_oop)) {
 332       oop obj = CompressedOops::decode_not_null(heap_oop);
 333 
 334       // Note: not all the oops embedded in the nmethod are in the
 335       // current region. We only look at those which are.
 336       if (_hr->is_in(obj)) {
 337         // Object is in the region. Check that its less than top
 338         if (_hr->top() <= (HeapWord*)obj) {
 339           // Object is above top
 340           log_error(gc, verify)("Object " PTR_FORMAT " in region " HR_FORMAT " is above top ",
 341                                 p2i(obj), HR_FORMAT_PARAMS(_hr));
 342           _failures = true;
 343           return;
 344         }
 345         // Nmethod has at least one oop in the current region
 346         _has_oops_in_region = true;
 347       }
 348     }
 349   }
 350 
 351 public:
 352   VerifyStrongCodeRootOopClosure(const HeapRegion* hr):
 353     _hr(hr), _failures(false), _has_oops_in_region(false) {}
 354 
 355   void do_oop(narrowOop* p) { do_oop_work(p); }
 356   void do_oop(oop* p)       { do_oop_work(p); }
 357 
 358   bool failures()           { return _failures; }
 359   bool has_oops_in_region() { return _has_oops_in_region; }
 360 };
 361 
 362 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
 363   const HeapRegion* _hr;
 364   bool _failures;
 365 public:
 366   VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
 367     _hr(hr), _failures(false) {}
 368 
 369   void do_code_blob(CodeBlob* cb) {
 370     nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null();
 371     if (nm != NULL) {
 372       // Verify that the nemthod is live
 373       if (!nm->is_alive()) {
 374         log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
 375                               p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 376         _failures = true;
 377       } else {
 378         VerifyStrongCodeRootOopClosure oop_cl(_hr);
 379         nm->oops_do(&oop_cl);
 380         if (!oop_cl.has_oops_in_region()) {
 381           log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
 382                                 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 383           _failures = true;
 384         } else if (oop_cl.failures()) {
 385           log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
 386                                 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
 387           _failures = true;
 388         }
 389       }
 390     }
 391   }
 392 
 393   bool failures()       { return _failures; }
 394 };
 395 
 396 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
 397   if (!G1VerifyHeapRegionCodeRoots) {
 398     // We're not verifying code roots.
 399     return;
 400   }
 401   if (vo == VerifyOption_G1UseFullMarking) {
 402     // Marking verification during a full GC is performed after class
 403     // unloading, code cache unloading, etc so the strong code roots
 404     // attached to each heap region are in an inconsistent state. They won't
 405     // be consistent until the strong code roots are rebuilt after the
 406     // actual GC. Skip verifying the strong code roots in this particular
 407     // time.
 408     assert(VerifyDuringGC, "only way to get here");
 409     return;
 410   }
 411 
 412   HeapRegionRemSet* hrrs = rem_set();
 413   size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
 414 
 415   // if this region is empty then there should be no entries
 416   // on its strong code root list
 417   if (is_empty()) {
 418     if (strong_code_roots_length > 0) {
 419       log_error(gc, verify)("region " HR_FORMAT " is empty but has " SIZE_FORMAT " code root entries",
 420                             HR_FORMAT_PARAMS(this), strong_code_roots_length);
 421       *failures = true;
 422     }
 423     return;
 424   }
 425 
 426   if (is_continues_humongous()) {
 427     if (strong_code_roots_length > 0) {
 428       log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
 429                             HR_FORMAT_PARAMS(this), strong_code_roots_length);
 430       *failures = true;
 431     }
 432     return;
 433   }
 434 
 435   VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
 436   strong_code_roots_do(&cb_cl);
 437 
 438   if (cb_cl.failures()) {
 439     *failures = true;
 440   }
 441 }
 442 
 443 void HeapRegion::print() const { print_on(tty); }
 444 void HeapRegion::print_on(outputStream* st) const {
 445   st->print("|%4u", this->_hrm_index);
 446   st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
 447             p2i(bottom()), p2i(top()), p2i(end()));
 448   st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
 449   st->print("|%2s", get_short_type_str());
 450   if (in_collection_set()) {
 451     st->print("|CS");
 452   } else {
 453     st->print("|  ");
 454   }
 455   st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "| %s ",
 456                p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()), rem_set()->get_state_str());
 457 }
 458 
 459 class G1VerificationClosure : public BasicOopIterateClosure {
 460 protected:
 461   G1CollectedHeap* _g1h;
 462   G1CardTable *_ct;
 463   oop _containing_obj;
 464   bool _failures;
 465   int _n_failures;
 466   VerifyOption _vo;
 467 public:
 468   // _vo == UsePrevMarking -> use "prev" marking information,
 469   // _vo == UseNextMarking -> use "next" marking information,
 470   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS.
 471   G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
 472     _g1h(g1h), _ct(g1h->card_table()),
 473     _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
 474   }
 475 
 476   void set_containing_obj(oop obj) {
 477     _containing_obj = obj;
 478   }
 479 
 480   bool failures() { return _failures; }
 481   int n_failures() { return _n_failures; }
 482 
 483   void print_object(outputStream* out, oop obj) {
 484 #ifdef PRODUCT
 485     Klass* k = obj->klass();
 486     const char* class_name = k->external_name();
 487     out->print_cr("class name %s", class_name);
 488 #else // PRODUCT
 489     obj->print_on(out);
 490 #endif // PRODUCT
 491   }
 492 
 493   // This closure provides its own oop verification code.
 494   debug_only(virtual bool should_verify_oops() { return false; })
 495 };
 496 
 497 class VerifyLiveClosure : public G1VerificationClosure {
 498 public:
 499   VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
 500   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
 501   virtual void do_oop(oop* p) { do_oop_work(p); }
 502 
 503   template <class T>
 504   void do_oop_work(T* p) {
 505     assert(_containing_obj != NULL, "Precondition");
 506     assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
 507       "Precondition");
 508     verify_liveness(p);
 509   }
 510 
 511   template <class T>
 512   void verify_liveness(T* p) {
 513     T heap_oop = RawAccess<>::oop_load(p);
 514     Log(gc, verify) log;
 515     if (!CompressedOops::is_null(heap_oop)) {
 516       oop obj = CompressedOops::decode_not_null(heap_oop);
 517       bool failed = false;
 518       if (!_g1h->is_in(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
 519         MutexLocker x(ParGCRareEvent_lock,
 520           Mutex::_no_safepoint_check_flag);
 521 
 522         if (!_failures) {
 523           log.error("----------");
 524         }
 525         ResourceMark rm;
 526         if (!_g1h->is_in(obj)) {
 527           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 528           log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region " HR_FORMAT,
 529                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 530           LogStream ls(log.error());
 531           print_object(&ls, _containing_obj);
 532           HeapRegion* const to = _g1h->heap_region_containing(obj);
 533           log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT " remset %s",
 534                     p2i(obj), HR_FORMAT_PARAMS(to), to->rem_set()->get_state_str());
 535         } else {
 536           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 537           HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
 538           log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region " HR_FORMAT,
 539                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 540           LogStream ls(log.error());
 541           print_object(&ls, _containing_obj);
 542           log.error("points to dead obj " PTR_FORMAT " in region " HR_FORMAT,
 543                     p2i(obj), HR_FORMAT_PARAMS(to));
 544           print_object(&ls, obj);
 545         }
 546         log.error("----------");
 547         _failures = true;
 548         failed = true;
 549         _n_failures++;
 550       }
 551     }
 552   }
 553 };
 554 
 555 class VerifyRemSetClosure : public G1VerificationClosure {
 556 public:
 557   VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
 558   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
 559   virtual void do_oop(oop* p) { do_oop_work(p); }
 560 
 561   template <class T>
 562   void do_oop_work(T* p) {
 563     assert(_containing_obj != NULL, "Precondition");
 564     assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
 565       "Precondition");
 566     verify_remembered_set(p);
 567   }
 568 
 569   template <class T>
 570   void verify_remembered_set(T* p) {
 571     T heap_oop = RawAccess<>::oop_load(p);
 572     Log(gc, verify) log;
 573     if (!CompressedOops::is_null(heap_oop)) {
 574       oop obj = CompressedOops::decode_not_null(heap_oop);
 575       HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
 576       HeapRegion* to = _g1h->heap_region_containing(obj);
 577       if (from != NULL && to != NULL &&
 578         from != to &&
 579         !to->is_pinned() &&
 580         to->rem_set()->is_complete()) {
 581         jbyte cv_obj = *_ct->byte_for_const(_containing_obj);
 582         jbyte cv_field = *_ct->byte_for_const(p);
 583         const jbyte dirty = G1CardTable::dirty_card_val();
 584 
 585         bool is_bad = !(from->is_young()
 586           || to->rem_set()->contains_reference(p)
 587           || (_containing_obj->is_objArray() ?
 588                 cv_field == dirty :
 589                 cv_obj == dirty || cv_field == dirty));
 590         if (is_bad) {
 591           MutexLocker x(ParGCRareEvent_lock,
 592             Mutex::_no_safepoint_check_flag);
 593 
 594           if (!_failures) {
 595             log.error("----------");
 596           }
 597           log.error("Missing rem set entry:");
 598           log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT " in region " HR_FORMAT,
 599                     p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
 600           ResourceMark rm;
 601           LogStream ls(log.error());
 602           _containing_obj->print_on(&ls);
 603           log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT " remset %s",
 604                     p2i(obj), HR_FORMAT_PARAMS(to), to->rem_set()->get_state_str());
 605           if (oopDesc::is_oop(obj)) {
 606             obj->print_on(&ls);
 607           }
 608           log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
 609           log.error("----------");
 610           _failures = true;
 611           _n_failures++;
 612         }
 613       }
 614     }
 615   }
 616 };
 617 
 618 // Closure that applies the given two closures in sequence.
 619 class G1Mux2Closure : public BasicOopIterateClosure {
 620   OopClosure* _c1;
 621   OopClosure* _c2;
 622 public:
 623   G1Mux2Closure(OopClosure *c1, OopClosure *c2) { _c1 = c1; _c2 = c2; }
 624   template <class T> inline void do_oop_work(T* p) {
 625     // Apply first closure; then apply the second.
 626     _c1->do_oop(p);
 627     _c2->do_oop(p);
 628   }
 629   virtual inline void do_oop(oop* p) { do_oop_work(p); }
 630   virtual inline void do_oop(narrowOop* p) { do_oop_work(p); }
 631 
 632   // This closure provides its own oop verification code.
 633   debug_only(virtual bool should_verify_oops() { return false; })
 634 };
 635 
 636 // This really ought to be commoned up into OffsetTableContigSpace somehow.
 637 // We would need a mechanism to make that code skip dead objects.
 638 
 639 void HeapRegion::verify(VerifyOption vo,
 640                         bool* failures) const {
 641   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 642   *failures = false;
 643   HeapWord* p = bottom();
 644   HeapWord* prev_p = NULL;
 645   VerifyLiveClosure vl_cl(g1h, vo);
 646   VerifyRemSetClosure vr_cl(g1h, vo);
 647   bool is_region_humongous = is_humongous();
 648   size_t object_num = 0;
 649   while (p < top()) {
 650     oop obj = oop(p);
 651     size_t obj_size = block_size(p);
 652     object_num += 1;
 653 
 654     if (!g1h->is_obj_dead_cond(obj, this, vo)) {
 655       if (oopDesc::is_oop(obj)) {
 656         Klass* klass = obj->klass();
 657         bool is_metaspace_object = Metaspace::contains(klass);
 658         if (!is_metaspace_object) {
 659           log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
 660                                 "not metadata", p2i(klass), p2i(obj));
 661           *failures = true;
 662           return;
 663         } else if (!klass->is_klass()) {
 664           log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
 665                                 "not a klass", p2i(klass), p2i(obj));
 666           *failures = true;
 667           return;
 668         } else {
 669           vl_cl.set_containing_obj(obj);
 670           if (!g1h->collector_state()->in_full_gc() || G1VerifyRSetsDuringFullGC) {
 671             // verify liveness and rem_set
 672             vr_cl.set_containing_obj(obj);
 673             G1Mux2Closure mux(&vl_cl, &vr_cl);
 674             obj->oop_iterate(&mux);
 675 
 676             if (vr_cl.failures()) {
 677               *failures = true;
 678             }
 679             if (G1MaxVerifyFailures >= 0 &&
 680               vr_cl.n_failures() >= G1MaxVerifyFailures) {
 681               return;
 682             }
 683           } else {
 684             // verify only liveness
 685             obj->oop_iterate(&vl_cl);
 686           }
 687           if (vl_cl.failures()) {
 688             *failures = true;
 689           }
 690           if (G1MaxVerifyFailures >= 0 &&
 691               vl_cl.n_failures() >= G1MaxVerifyFailures) {
 692             return;
 693           }
 694         }
 695       } else {
 696         log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
 697         *failures = true;
 698         return;
 699       }
 700     }
 701     prev_p = p;
 702     p += obj_size;
 703   }
 704 
 705   if (!is_young() && !is_empty()) {
 706     _bot_part.verify();
 707   }
 708 
 709   if (is_region_humongous) {
 710     oop obj = oop(this->humongous_start_region()->bottom());
 711     if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
 712       log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
 713       *failures = true;
 714       return;
 715     }
 716   }
 717 
 718   if (!is_region_humongous && p != top()) {
 719     log_error(gc, verify)("end of last object " PTR_FORMAT " "
 720                           "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
 721     *failures = true;
 722     return;
 723   }
 724 
 725   HeapWord* the_end = end();
 726   // Do some extra BOT consistency checking for addresses in the
 727   // range [top, end). BOT look-ups in this range should yield
 728   // top. No point in doing that if top == end (there's nothing there).
 729   if (p < the_end) {
 730     // Look up top
 731     HeapWord* addr_1 = p;
 732     HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
 733     if (b_start_1 != p) {
 734       log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
 735                             " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 736                             p2i(addr_1), p2i(b_start_1), p2i(p));
 737       *failures = true;
 738       return;
 739     }
 740 
 741     // Look up top + 1
 742     HeapWord* addr_2 = p + 1;
 743     if (addr_2 < the_end) {
 744       HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
 745       if (b_start_2 != p) {
 746         log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
 747                               " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 748                               p2i(addr_2), p2i(b_start_2), p2i(p));
 749         *failures = true;
 750         return;
 751       }
 752     }
 753 
 754     // Look up an address between top and end
 755     size_t diff = pointer_delta(the_end, p) / 2;
 756     HeapWord* addr_3 = p + diff;
 757     if (addr_3 < the_end) {
 758       HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
 759       if (b_start_3 != p) {
 760         log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
 761                               " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 762                               p2i(addr_3), p2i(b_start_3), p2i(p));
 763         *failures = true;
 764         return;
 765       }
 766     }
 767 
 768     // Look up end - 1
 769     HeapWord* addr_4 = the_end - 1;
 770     HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
 771     if (b_start_4 != p) {
 772       log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
 773                             " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
 774                             p2i(addr_4), p2i(b_start_4), p2i(p));
 775       *failures = true;
 776       return;
 777     }
 778   }
 779 
 780   verify_strong_code_roots(vo, failures);
 781 }
 782 
 783 void HeapRegion::verify() const {
 784   bool dummy = false;
 785   verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
 786 }
 787 
 788 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
 789   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 790   *failures = false;
 791   HeapWord* p = bottom();
 792   HeapWord* prev_p = NULL;
 793   VerifyRemSetClosure vr_cl(g1h, vo);
 794   while (p < top()) {
 795     oop obj = oop(p);
 796     size_t obj_size = block_size(p);
 797 
 798     if (!g1h->is_obj_dead_cond(obj, this, vo)) {
 799       if (oopDesc::is_oop(obj)) {
 800         vr_cl.set_containing_obj(obj);
 801         obj->oop_iterate(&vr_cl);
 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         log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
 812         *failures = true;
 813         return;
 814       }
 815     }
 816 
 817     prev_p = p;
 818     p += obj_size;
 819   }
 820 }
 821 
 822 void HeapRegion::verify_rem_set() const {
 823   bool failures = false;
 824   verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
 825   guarantee(!failures, "HeapRegion RemSet verification failed");
 826 }
 827 
 828 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
 829   // Not used for G1 anymore, but pure virtual in Space.
 830   ShouldNotReachHere();
 831 }
 832 
 833 // G1OffsetTableContigSpace code; copied from space.cpp.  Hope this can go
 834 // away eventually.
 835 
 836 void G1ContiguousSpace::clear(bool mangle_space) {
 837   set_top(bottom());
 838   CompactibleSpace::clear(mangle_space);
 839   reset_bot();
 840 }
 841 #ifndef PRODUCT
 842 void G1ContiguousSpace::mangle_unused_area() {
 843   mangle_unused_area_complete();
 844 }
 845 
 846 void G1ContiguousSpace::mangle_unused_area_complete() {
 847   SpaceMangler::mangle_region(MemRegion(top(), end()));
 848 }
 849 #endif
 850 
 851 void G1ContiguousSpace::print() const {
 852   print_short();
 853   tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
 854                 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
 855                 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
 856 }
 857 
 858 HeapWord* G1ContiguousSpace::initialize_threshold() {
 859   return _bot_part.initialize_threshold();
 860 }
 861 
 862 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
 863                                                     HeapWord* end) {
 864   _bot_part.alloc_block(start, end);
 865   return _bot_part.threshold();
 866 }
 867 
 868 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
 869   object_iterate(blk);
 870 }
 871 
 872 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
 873   HeapWord* p = bottom();
 874   while (p < top()) {
 875     if (block_is_obj(p)) {
 876       blk->do_object(oop(p));
 877     }
 878     p += block_size(p);
 879   }
 880 }
 881 
 882 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
 883   _top(NULL),
 884   _bot_part(bot, this),
 885   _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
 886   _pre_dummy_top(NULL)
 887 {
 888 }
 889 
 890 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
 891   CompactibleSpace::initialize(mr, clear_space, mangle_space);
 892   _top = bottom();
 893   set_saved_mark_word(NULL);
 894   reset_bot();
 895 }