1 /*
   2  * Copyright (c) 2001, 2014, 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 "gc_implementation/g1/concurrentG1Refine.hpp"
  27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
  28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
  29 #include "gc_implementation/g1/heapRegionRemSet.hpp"
  30 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
  31 #include "memory/allocation.hpp"
  32 #include "memory/padded.inline.hpp"
  33 #include "memory/space.inline.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "runtime/atomic.inline.hpp"
  36 #include "utilities/bitMap.inline.hpp"
  37 #include "utilities/globalDefinitions.hpp"
  38 #include "utilities/growableArray.hpp"
  39 
  40 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  41 
  42 class PerRegionTable: public CHeapObj<mtGC> {
  43   friend class OtherRegionsTable;
  44   friend class HeapRegionRemSetIterator;
  45 
  46   HeapRegion*     _hr;
  47   BitMap          _bm;
  48   jint            _occupied;
  49 
  50   // next pointer for free/allocated 'all' list
  51   PerRegionTable* _next;
  52 
  53   // prev pointer for the allocated 'all' list
  54   PerRegionTable* _prev;
  55 
  56   // next pointer in collision list
  57   PerRegionTable * _collision_list_next;
  58 
  59   // Global free list of PRTs
  60   static PerRegionTable* _free_list;
  61 
  62 protected:
  63   // We need access in order to union things into the base table.
  64   BitMap* bm() { return &_bm; }
  65 
  66   void recount_occupied() {
  67     _occupied = (jint) bm()->count_one_bits();
  68   }
  69 
  70   PerRegionTable(HeapRegion* hr) :
  71     _hr(hr),
  72     _occupied(0),
  73     _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
  74     _collision_list_next(NULL), _next(NULL), _prev(NULL)
  75   {}
  76 
  77   void add_card_work(CardIdx_t from_card, bool par) {
  78     if (!_bm.at(from_card)) {
  79       if (par) {
  80         if (_bm.par_at_put(from_card, 1)) {
  81           Atomic::inc(&_occupied);
  82         }
  83       } else {
  84         _bm.at_put(from_card, 1);
  85         _occupied++;
  86       }
  87     }
  88   }
  89 
  90   void add_reference_work(OopOrNarrowOopStar from, bool par) {
  91     // Must make this robust in case "from" is not in "_hr", because of
  92     // concurrency.
  93 
  94     if (G1TraceHeapRegionRememberedSet) {
  95       gclog_or_tty->print_cr("    PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
  96                              from,
  97                              UseCompressedOops
  98                              ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
  99                              : (void *)oopDesc::load_decode_heap_oop((oop*)from));
 100     }
 101 
 102     HeapRegion* loc_hr = hr();
 103     // If the test below fails, then this table was reused concurrently
 104     // with this operation.  This is OK, since the old table was coarsened,
 105     // and adding a bit to the new table is never incorrect.
 106     // If the table used to belong to a continues humongous region and is
 107     // now reused for the corresponding start humongous region, we need to
 108     // make sure that we detect this. Thus, we call is_in_reserved_raw()
 109     // instead of just is_in_reserved() here.
 110     if (loc_hr->is_in_reserved_raw(from)) {
 111       size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
 112       CardIdx_t from_card = (CardIdx_t)
 113           hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
 114 
 115       assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
 116              "Must be in range.");
 117       add_card_work(from_card, par);
 118     }
 119   }
 120 
 121 public:
 122 
 123   HeapRegion* hr() const { return _hr; }
 124 
 125   jint occupied() const {
 126     // Overkill, but if we ever need it...
 127     // guarantee(_occupied == _bm.count_one_bits(), "Check");
 128     return _occupied;
 129   }
 130 
 131   void init(HeapRegion* hr, bool clear_links_to_all_list) {
 132     if (clear_links_to_all_list) {
 133       set_next(NULL);
 134       set_prev(NULL);
 135     }
 136     _hr = hr;
 137     _collision_list_next = NULL;
 138     _occupied = 0;
 139     _bm.clear();
 140   }
 141 
 142   void add_reference(OopOrNarrowOopStar from) {
 143     add_reference_work(from, /*parallel*/ true);
 144   }
 145 
 146   void seq_add_reference(OopOrNarrowOopStar from) {
 147     add_reference_work(from, /*parallel*/ false);
 148   }
 149 
 150   void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
 151     HeapWord* hr_bot = hr()->bottom();
 152     size_t hr_first_card_index = ctbs->index_for(hr_bot);
 153     bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
 154     recount_occupied();
 155   }
 156 
 157   void add_card(CardIdx_t from_card_index) {
 158     add_card_work(from_card_index, /*parallel*/ true);
 159   }
 160 
 161   void seq_add_card(CardIdx_t from_card_index) {
 162     add_card_work(from_card_index, /*parallel*/ false);
 163   }
 164 
 165   // (Destructively) union the bitmap of the current table into the given
 166   // bitmap (which is assumed to be of the same size.)
 167   void union_bitmap_into(BitMap* bm) {
 168     bm->set_union(_bm);
 169   }
 170 
 171   // Mem size in bytes.
 172   size_t mem_size() const {
 173     return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize;
 174   }
 175 
 176   // Requires "from" to be in "hr()".
 177   bool contains_reference(OopOrNarrowOopStar from) const {
 178     assert(hr()->is_in_reserved(from), "Precondition.");
 179     size_t card_ind = pointer_delta(from, hr()->bottom(),
 180                                     CardTableModRefBS::card_size);
 181     return _bm.at(card_ind);
 182   }
 183 
 184   // Bulk-free the PRTs from prt to last, assumes that they are
 185   // linked together using their _next field.
 186   static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
 187     while (true) {
 188       PerRegionTable* fl = _free_list;
 189       last->set_next(fl);
 190       PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
 191       if (res == fl) {
 192         return;
 193       }
 194     }
 195     ShouldNotReachHere();
 196   }
 197 
 198   static void free(PerRegionTable* prt) {
 199     bulk_free(prt, prt);
 200   }
 201 
 202   // Returns an initialized PerRegionTable instance.
 203   static PerRegionTable* alloc(HeapRegion* hr) {
 204     PerRegionTable* fl = _free_list;
 205     while (fl != NULL) {
 206       PerRegionTable* nxt = fl->next();
 207       PerRegionTable* res =
 208         (PerRegionTable*)
 209         Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
 210       if (res == fl) {
 211         fl->init(hr, true);
 212         return fl;
 213       } else {
 214         fl = _free_list;
 215       }
 216     }
 217     assert(fl == NULL, "Loop condition.");
 218     return new PerRegionTable(hr);
 219   }
 220 
 221   PerRegionTable* next() const { return _next; }
 222   void set_next(PerRegionTable* next) { _next = next; }
 223   PerRegionTable* prev() const { return _prev; }
 224   void set_prev(PerRegionTable* prev) { _prev = prev; }
 225 
 226   // Accessor and Modification routines for the pointer for the
 227   // singly linked collision list that links the PRTs within the
 228   // OtherRegionsTable::_fine_grain_regions hash table.
 229   //
 230   // It might be useful to also make the collision list doubly linked
 231   // to avoid iteration over the collisions list during scrubbing/deletion.
 232   // OTOH there might not be many collisions.
 233 
 234   PerRegionTable* collision_list_next() const {
 235     return _collision_list_next;
 236   }
 237 
 238   void set_collision_list_next(PerRegionTable* next) {
 239     _collision_list_next = next;
 240   }
 241 
 242   PerRegionTable** collision_list_next_addr() {
 243     return &_collision_list_next;
 244   }
 245 
 246   static size_t fl_mem_size() {
 247     PerRegionTable* cur = _free_list;
 248     size_t res = 0;
 249     while (cur != NULL) {
 250       res += cur->mem_size();
 251       cur = cur->next();
 252     }
 253     return res;
 254   }
 255 
 256   static void test_fl_mem_size();
 257 };
 258 
 259 PerRegionTable* PerRegionTable::_free_list = NULL;
 260 
 261 size_t OtherRegionsTable::_max_fine_entries = 0;
 262 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
 263 size_t OtherRegionsTable::_fine_eviction_stride = 0;
 264 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
 265 
 266 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
 267   _g1h(G1CollectedHeap::heap()),
 268   _hr(hr), _m(m),
 269   _coarse_map(G1CollectedHeap::heap()->max_regions(),
 270               false /* in-resource-area */),
 271   _fine_grain_regions(NULL),
 272   _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
 273   _n_fine_entries(0), _n_coarse_entries(0),
 274   _fine_eviction_start(0),
 275   _sparse_table(hr)
 276 {
 277   typedef PerRegionTable* PerRegionTablePtr;
 278 
 279   if (_max_fine_entries == 0) {
 280     assert(_mod_max_fine_entries_mask == 0, "Both or none.");
 281     size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
 282     _max_fine_entries = (size_t)1 << max_entries_log;
 283     _mod_max_fine_entries_mask = _max_fine_entries - 1;
 284 
 285     assert(_fine_eviction_sample_size == 0
 286            && _fine_eviction_stride == 0, "All init at same time.");
 287     _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
 288     _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
 289   }
 290 
 291   _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
 292                         mtGC, 0, AllocFailStrategy::RETURN_NULL);
 293 
 294   if (_fine_grain_regions == NULL) {
 295     vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
 296                           "Failed to allocate _fine_grain_entries.");
 297   }
 298 
 299   for (size_t i = 0; i < _max_fine_entries; i++) {
 300     _fine_grain_regions[i] = NULL;
 301   }
 302 }
 303 
 304 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
 305   // We always append to the beginning of the list for convenience;
 306   // the order of entries in this list does not matter.
 307   if (_first_all_fine_prts != NULL) {
 308     assert(_first_all_fine_prts->prev() == NULL, "invariant");
 309     _first_all_fine_prts->set_prev(prt);
 310     prt->set_next(_first_all_fine_prts);
 311   } else {
 312     // this is the first element we insert. Adjust the "last" pointer
 313     _last_all_fine_prts = prt;
 314     assert(prt->next() == NULL, "just checking");
 315   }
 316   // the new element is always the first element without a predecessor
 317   prt->set_prev(NULL);
 318   _first_all_fine_prts = prt;
 319 
 320   assert(prt->prev() == NULL, "just checking");
 321   assert(_first_all_fine_prts == prt, "just checking");
 322   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
 323          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
 324          "just checking");
 325   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
 326          "just checking");
 327   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
 328          "just checking");
 329 }
 330 
 331 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
 332   if (prt->prev() != NULL) {
 333     assert(_first_all_fine_prts != prt, "just checking");
 334     prt->prev()->set_next(prt->next());
 335     // removing the last element in the list?
 336     if (_last_all_fine_prts == prt) {
 337       _last_all_fine_prts = prt->prev();
 338     }
 339   } else {
 340     assert(_first_all_fine_prts == prt, "just checking");
 341     _first_all_fine_prts = prt->next();
 342     // list is empty now?
 343     if (_first_all_fine_prts == NULL) {
 344       _last_all_fine_prts = NULL;
 345     }
 346   }
 347 
 348   if (prt->next() != NULL) {
 349     prt->next()->set_prev(prt->prev());
 350   }
 351 
 352   prt->set_next(NULL);
 353   prt->set_prev(NULL);
 354 
 355   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
 356          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
 357          "just checking");
 358   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
 359          "just checking");
 360   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
 361          "just checking");
 362 }
 363 
 364 int**  FromCardCache::_cache = NULL;
 365 uint   FromCardCache::_max_regions = 0;
 366 size_t FromCardCache::_static_mem_size = 0;
 367 
 368 void FromCardCache::initialize(uint n_par_rs, uint max_num_regions) {
 369   guarantee(_cache == NULL, "Should not call this multiple times");
 370 
 371   _max_regions = max_num_regions;
 372   _cache = Padded2DArray<int, mtGC>::create_unfreeable(n_par_rs,
 373                                                        _max_regions,
 374                                                        &_static_mem_size);
 375 
 376   for (uint i = 0; i < n_par_rs; i++) {
 377     for (uint j = 0; j < _max_regions; j++) {
 378       set(i, j, InvalidCard);
 379     }
 380   }
 381 }
 382 
 383 void FromCardCache::shrink(uint new_num_regions) {
 384   for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
 385     assert(new_num_regions <= _max_regions, "Must be within max.");
 386     for (uint j = new_num_regions; j < _max_regions; j++) {
 387       set(i, j, InvalidCard);
 388     }
 389   }
 390 }
 391 
 392 #ifndef PRODUCT
 393 void FromCardCache::print(outputStream* out) {
 394   for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
 395     for (uint j = 0; j < _max_regions; j++) {
 396       out->print_cr("_from_card_cache[%u][%u] = %d.",
 397                     i, j, at(i, j));
 398     }
 399   }
 400 }
 401 #endif
 402 
 403 void FromCardCache::clear(uint region_idx) {
 404   uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
 405   for (uint i = 0; i < num_par_remsets; i++) {
 406     set(i, region_idx, InvalidCard);
 407   }
 408 }
 409 
 410 void OtherRegionsTable::init_from_card_cache(uint max_regions) {
 411   FromCardCache::initialize(HeapRegionRemSet::num_par_rem_sets(), max_regions);
 412 }
 413 
 414 void OtherRegionsTable::shrink_from_card_cache(uint new_num_regions) {
 415   FromCardCache::shrink(new_num_regions);
 416 }
 417 
 418 void OtherRegionsTable::print_from_card_cache() {
 419   FromCardCache::print();
 420 }
 421 
 422 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, int tid) {
 423   uint cur_hrs_ind = hr()->hrs_index();
 424 
 425   if (G1TraceHeapRegionRememberedSet) {
 426     gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
 427                                                     from,
 428                                                     UseCompressedOops
 429                                                     ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
 430                                                     : (void *)oopDesc::load_decode_heap_oop((oop*)from));
 431   }
 432 
 433   int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
 434 
 435   if (G1TraceHeapRegionRememberedSet) {
 436     gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = %d)",
 437                   hr()->bottom(), from_card,
 438                   FromCardCache::at((uint)tid, cur_hrs_ind));
 439   }
 440 
 441   if (FromCardCache::contains_or_replace((uint)tid, cur_hrs_ind, from_card)) {
 442     if (G1TraceHeapRegionRememberedSet) {
 443       gclog_or_tty->print_cr("  from-card cache hit.");
 444     }
 445     assert(contains_reference(from), "We just added it!");
 446     return;
 447   }
 448 
 449   // Note that this may be a continued H region.
 450   HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
 451   RegionIdx_t from_hrs_ind = (RegionIdx_t) from_hr->hrs_index();
 452 
 453   // If the region is already coarsened, return.
 454   if (_coarse_map.at(from_hrs_ind)) {
 455     if (G1TraceHeapRegionRememberedSet) {
 456       gclog_or_tty->print_cr("  coarse map hit.");
 457     }
 458     assert(contains_reference(from), "We just added it!");
 459     return;
 460   }
 461 
 462   // Otherwise find a per-region table to add it to.
 463   size_t ind = from_hrs_ind & _mod_max_fine_entries_mask;
 464   PerRegionTable* prt = find_region_table(ind, from_hr);
 465   if (prt == NULL) {
 466     MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
 467     // Confirm that it's really not there...
 468     prt = find_region_table(ind, from_hr);
 469     if (prt == NULL) {
 470 
 471       uintptr_t from_hr_bot_card_index =
 472         uintptr_t(from_hr->bottom())
 473           >> CardTableModRefBS::card_shift;
 474       CardIdx_t card_index = from_card - from_hr_bot_card_index;
 475       assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
 476              "Must be in range.");
 477       if (G1HRRSUseSparseTable &&
 478           _sparse_table.add_card(from_hrs_ind, card_index)) {
 479         if (G1RecordHRRSOops) {
 480           HeapRegionRemSet::record(hr(), from);
 481           if (G1TraceHeapRegionRememberedSet) {
 482             gclog_or_tty->print("   Added card " PTR_FORMAT " to region "
 483                                 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
 484                                 align_size_down(uintptr_t(from),
 485                                                 CardTableModRefBS::card_size),
 486                                 hr()->bottom(), from);
 487           }
 488         }
 489         if (G1TraceHeapRegionRememberedSet) {
 490           gclog_or_tty->print_cr("   added card to sparse table.");
 491         }
 492         assert(contains_reference_locked(from), "We just added it!");
 493         return;
 494       } else {
 495         if (G1TraceHeapRegionRememberedSet) {
 496           gclog_or_tty->print_cr("   [tid %d] sparse table entry "
 497                         "overflow(f: %d, t: %u)",
 498                         tid, from_hrs_ind, cur_hrs_ind);
 499         }
 500       }
 501 
 502       if (_n_fine_entries == _max_fine_entries) {
 503         prt = delete_region_table();
 504         // There is no need to clear the links to the 'all' list here:
 505         // prt will be reused immediately, i.e. remain in the 'all' list.
 506         prt->init(from_hr, false /* clear_links_to_all_list */);
 507       } else {
 508         prt = PerRegionTable::alloc(from_hr);
 509         link_to_all(prt);
 510       }
 511 
 512       PerRegionTable* first_prt = _fine_grain_regions[ind];
 513       prt->set_collision_list_next(first_prt);
 514       _fine_grain_regions[ind] = prt;
 515       _n_fine_entries++;
 516 
 517       if (G1HRRSUseSparseTable) {
 518         // Transfer from sparse to fine-grain.
 519         SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrs_ind);
 520         assert(sprt_entry != NULL, "There should have been an entry");
 521         for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
 522           CardIdx_t c = sprt_entry->card(i);
 523           if (c != SparsePRTEntry::NullEntry) {
 524             prt->add_card(c);
 525           }
 526         }
 527         // Now we can delete the sparse entry.
 528         bool res = _sparse_table.delete_entry(from_hrs_ind);
 529         assert(res, "It should have been there.");
 530       }
 531     }
 532     assert(prt != NULL && prt->hr() == from_hr, "consequence");
 533   }
 534   // Note that we can't assert "prt->hr() == from_hr", because of the
 535   // possibility of concurrent reuse.  But see head comment of
 536   // OtherRegionsTable for why this is OK.
 537   assert(prt != NULL, "Inv");
 538 
 539   prt->add_reference(from);
 540 
 541   if (G1RecordHRRSOops) {
 542     HeapRegionRemSet::record(hr(), from);
 543     if (G1TraceHeapRegionRememberedSet) {
 544       gclog_or_tty->print("Added card " PTR_FORMAT " to region "
 545                           "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
 546                           align_size_down(uintptr_t(from),
 547                                           CardTableModRefBS::card_size),
 548                           hr()->bottom(), from);
 549     }
 550   }
 551   assert(contains_reference(from), "We just added it!");
 552 }
 553 
 554 PerRegionTable*
 555 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
 556   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
 557   PerRegionTable* prt = _fine_grain_regions[ind];
 558   while (prt != NULL && prt->hr() != hr) {
 559     prt = prt->collision_list_next();
 560   }
 561   // Loop postcondition is the method postcondition.
 562   return prt;
 563 }
 564 
 565 jint OtherRegionsTable::_n_coarsenings = 0;
 566 
 567 PerRegionTable* OtherRegionsTable::delete_region_table() {
 568   assert(_m->owned_by_self(), "Precondition");
 569   assert(_n_fine_entries == _max_fine_entries, "Precondition");
 570   PerRegionTable* max = NULL;
 571   jint max_occ = 0;
 572   PerRegionTable** max_prev;
 573   size_t max_ind;
 574 
 575   size_t i = _fine_eviction_start;
 576   for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
 577     size_t ii = i;
 578     // Make sure we get a non-NULL sample.
 579     while (_fine_grain_regions[ii] == NULL) {
 580       ii++;
 581       if (ii == _max_fine_entries) ii = 0;
 582       guarantee(ii != i, "We must find one.");
 583     }
 584     PerRegionTable** prev = &_fine_grain_regions[ii];
 585     PerRegionTable* cur = *prev;
 586     while (cur != NULL) {
 587       jint cur_occ = cur->occupied();
 588       if (max == NULL || cur_occ > max_occ) {
 589         max = cur;
 590         max_prev = prev;
 591         max_ind = i;
 592         max_occ = cur_occ;
 593       }
 594       prev = cur->collision_list_next_addr();
 595       cur = cur->collision_list_next();
 596     }
 597     i = i + _fine_eviction_stride;
 598     if (i >= _n_fine_entries) i = i - _n_fine_entries;
 599   }
 600 
 601   _fine_eviction_start++;
 602 
 603   if (_fine_eviction_start >= _n_fine_entries) {
 604     _fine_eviction_start -= _n_fine_entries;
 605   }
 606 
 607   guarantee(max != NULL, "Since _n_fine_entries > 0");
 608 
 609   // Set the corresponding coarse bit.
 610   size_t max_hrs_index = (size_t) max->hr()->hrs_index();
 611   if (!_coarse_map.at(max_hrs_index)) {
 612     _coarse_map.at_put(max_hrs_index, true);
 613     _n_coarse_entries++;
 614     if (G1TraceHeapRegionRememberedSet) {
 615       gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
 616                  "for region [" PTR_FORMAT "...] (" SIZE_FORMAT " coarse entries).\n",
 617                  hr()->bottom(),
 618                  max->hr()->bottom(),
 619                  _n_coarse_entries);
 620     }
 621   }
 622 
 623   // Unsplice.
 624   *max_prev = max->collision_list_next();
 625   Atomic::inc(&_n_coarsenings);
 626   _n_fine_entries--;
 627   return max;
 628 }
 629 
 630 
 631 // At present, this must be called stop-world single-threaded.
 632 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
 633                               BitMap* region_bm, BitMap* card_bm) {
 634   // First eliminated garbage regions from the coarse map.
 635   if (G1RSScrubVerbose) {
 636     gclog_or_tty->print_cr("Scrubbing region %u:", hr()->hrs_index());
 637   }
 638 
 639   assert(_coarse_map.size() == region_bm->size(), "Precondition");
 640   if (G1RSScrubVerbose) {
 641     gclog_or_tty->print("   Coarse map: before = "SIZE_FORMAT"...",
 642                         _n_coarse_entries);
 643   }
 644   _coarse_map.set_intersection(*region_bm);
 645   _n_coarse_entries = _coarse_map.count_one_bits();
 646   if (G1RSScrubVerbose) {
 647     gclog_or_tty->print_cr("   after = "SIZE_FORMAT".", _n_coarse_entries);
 648   }
 649 
 650   // Now do the fine-grained maps.
 651   for (size_t i = 0; i < _max_fine_entries; i++) {
 652     PerRegionTable* cur = _fine_grain_regions[i];
 653     PerRegionTable** prev = &_fine_grain_regions[i];
 654     while (cur != NULL) {
 655       PerRegionTable* nxt = cur->collision_list_next();
 656       // If the entire region is dead, eliminate.
 657       if (G1RSScrubVerbose) {
 658         gclog_or_tty->print_cr("     For other region %u:",
 659                                cur->hr()->hrs_index());
 660       }
 661       if (!region_bm->at((size_t) cur->hr()->hrs_index())) {
 662         *prev = nxt;
 663         cur->set_collision_list_next(NULL);
 664         _n_fine_entries--;
 665         if (G1RSScrubVerbose) {
 666           gclog_or_tty->print_cr("          deleted via region map.");
 667         }
 668         unlink_from_all(cur);
 669         PerRegionTable::free(cur);
 670       } else {
 671         // Do fine-grain elimination.
 672         if (G1RSScrubVerbose) {
 673           gclog_or_tty->print("          occ: before = %4d.", cur->occupied());
 674         }
 675         cur->scrub(ctbs, card_bm);
 676         if (G1RSScrubVerbose) {
 677           gclog_or_tty->print_cr("          after = %4d.", cur->occupied());
 678         }
 679         // Did that empty the table completely?
 680         if (cur->occupied() == 0) {
 681           *prev = nxt;
 682           cur->set_collision_list_next(NULL);
 683           _n_fine_entries--;
 684           unlink_from_all(cur);
 685           PerRegionTable::free(cur);
 686         } else {
 687           prev = cur->collision_list_next_addr();
 688         }
 689       }
 690       cur = nxt;
 691     }
 692   }
 693   // Since we may have deleted a from_card_cache entry from the RS, clear
 694   // the FCC.
 695   clear_fcc();
 696 }
 697 
 698 
 699 size_t OtherRegionsTable::occupied() const {
 700   size_t sum = occ_fine();
 701   sum += occ_sparse();
 702   sum += occ_coarse();
 703   return sum;
 704 }
 705 
 706 size_t OtherRegionsTable::occ_fine() const {
 707   size_t sum = 0;
 708 
 709   size_t num = 0;
 710   PerRegionTable * cur = _first_all_fine_prts;
 711   while (cur != NULL) {
 712     sum += cur->occupied();
 713     cur = cur->next();
 714     num++;
 715   }
 716   guarantee(num == _n_fine_entries, "just checking");
 717   return sum;
 718 }
 719 
 720 size_t OtherRegionsTable::occ_coarse() const {
 721   return (_n_coarse_entries * HeapRegion::CardsPerRegion);
 722 }
 723 
 724 size_t OtherRegionsTable::occ_sparse() const {
 725   return _sparse_table.occupied();
 726 }
 727 
 728 size_t OtherRegionsTable::mem_size() const {
 729   size_t sum = 0;
 730   // all PRTs are of the same size so it is sufficient to query only one of them.
 731   if (_first_all_fine_prts != NULL) {
 732     assert(_last_all_fine_prts != NULL &&
 733       _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
 734     sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
 735   }
 736   sum += (sizeof(PerRegionTable*) * _max_fine_entries);
 737   sum += (_coarse_map.size_in_words() * HeapWordSize);
 738   sum += (_sparse_table.mem_size());
 739   sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above.
 740   return sum;
 741 }
 742 
 743 size_t OtherRegionsTable::static_mem_size() {
 744   return FromCardCache::static_mem_size();
 745 }
 746 
 747 size_t OtherRegionsTable::fl_mem_size() {
 748   return PerRegionTable::fl_mem_size();
 749 }
 750 
 751 void OtherRegionsTable::clear_fcc() {
 752   FromCardCache::clear(hr()->hrs_index());
 753 }
 754 
 755 void OtherRegionsTable::clear() {
 756   // if there are no entries, skip this step
 757   if (_first_all_fine_prts != NULL) {
 758     guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
 759     PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
 760     memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
 761   } else {
 762     guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
 763   }
 764 
 765   _first_all_fine_prts = _last_all_fine_prts = NULL;
 766   _sparse_table.clear();
 767   _coarse_map.clear();
 768   _n_fine_entries = 0;
 769   _n_coarse_entries = 0;
 770 
 771   clear_fcc();
 772 }
 773 
 774 bool OtherRegionsTable::del_single_region_table(size_t ind,
 775                                                 HeapRegion* hr) {
 776   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
 777   PerRegionTable** prev_addr = &_fine_grain_regions[ind];
 778   PerRegionTable* prt = *prev_addr;
 779   while (prt != NULL && prt->hr() != hr) {
 780     prev_addr = prt->collision_list_next_addr();
 781     prt = prt->collision_list_next();
 782   }
 783   if (prt != NULL) {
 784     assert(prt->hr() == hr, "Loop postcondition.");
 785     *prev_addr = prt->collision_list_next();
 786     unlink_from_all(prt);
 787     PerRegionTable::free(prt);
 788     _n_fine_entries--;
 789     return true;
 790   } else {
 791     return false;
 792   }
 793 }
 794 
 795 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
 796   // Cast away const in this case.
 797   MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag);
 798   return contains_reference_locked(from);
 799 }
 800 
 801 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
 802   HeapRegion* hr = _g1h->heap_region_containing_raw(from);
 803   RegionIdx_t hr_ind = (RegionIdx_t) hr->hrs_index();
 804   // Is this region in the coarse map?
 805   if (_coarse_map.at(hr_ind)) return true;
 806 
 807   PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
 808                                      hr);
 809   if (prt != NULL) {
 810     return prt->contains_reference(from);
 811 
 812   } else {
 813     uintptr_t from_card =
 814       (uintptr_t(from) >> CardTableModRefBS::card_shift);
 815     uintptr_t hr_bot_card_index =
 816       uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
 817     assert(from_card >= hr_bot_card_index, "Inv");
 818     CardIdx_t card_index = from_card - hr_bot_card_index;
 819     assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
 820            "Must be in range.");
 821     return _sparse_table.contains_card(hr_ind, card_index);
 822   }
 823 }
 824 
 825 void
 826 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
 827   _sparse_table.do_cleanup_work(hrrs_cleanup_task);
 828 }
 829 
 830 // Determines how many threads can add records to an rset in parallel.
 831 // This can be done by either mutator threads together with the
 832 // concurrent refinement threads or GC threads.
 833 uint HeapRegionRemSet::num_par_rem_sets() {
 834   return MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), (uint)ParallelGCThreads);
 835 }
 836 
 837 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
 838                                    HeapRegion* hr)
 839   : _bosa(bosa),
 840     _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrs_index()), true),
 841     _code_roots(), _other_regions(hr, &_m) {
 842   reset_for_par_iteration();
 843 }
 844 
 845 void HeapRegionRemSet::setup_remset_size() {
 846   // Setup sparse and fine-grain tables sizes.
 847   // table_size = base * (log(region_size / 1M) + 1)
 848   const int LOG_M = 20;
 849   int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
 850   if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
 851     G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
 852   }
 853   if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
 854     G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
 855   }
 856   guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
 857 }
 858 
 859 bool HeapRegionRemSet::claim_iter() {
 860   if (_iter_state != Unclaimed) return false;
 861   jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
 862   return (res == Unclaimed);
 863 }
 864 
 865 void HeapRegionRemSet::set_iter_complete() {
 866   _iter_state = Complete;
 867 }
 868 
 869 bool HeapRegionRemSet::iter_is_complete() {
 870   return _iter_state == Complete;
 871 }
 872 
 873 #ifndef PRODUCT
 874 void HeapRegionRemSet::print() {
 875   HeapRegionRemSetIterator iter(this);
 876   size_t card_index;
 877   while (iter.has_next(card_index)) {
 878     HeapWord* card_start =
 879       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
 880     gclog_or_tty->print_cr("  Card " PTR_FORMAT, card_start);
 881   }
 882   if (iter.n_yielded() != occupied()) {
 883     gclog_or_tty->print_cr("Yielded disagrees with occupied:");
 884     gclog_or_tty->print_cr("  " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6)
 885                   " coarse, " SIZE_FORMAT_W(6) " fine).",
 886                   iter.n_yielded(),
 887                   iter.n_yielded_coarse(), iter.n_yielded_fine());
 888     gclog_or_tty->print_cr("  " SIZE_FORMAT_W(6) " occ     (" SIZE_FORMAT_W(6)
 889                            " coarse, " SIZE_FORMAT_W(6) " fine).",
 890                   occupied(), occ_coarse(), occ_fine());
 891   }
 892   guarantee(iter.n_yielded() == occupied(),
 893             "We should have yielded all the represented cards.");
 894 }
 895 #endif
 896 
 897 void HeapRegionRemSet::cleanup() {
 898   SparsePRT::cleanup_all();
 899 }
 900 
 901 void HeapRegionRemSet::clear() {
 902   MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
 903   clear_locked();
 904 }
 905 
 906 void HeapRegionRemSet::clear_locked() {
 907   _code_roots.clear();
 908   _other_regions.clear();
 909   assert(occupied_locked() == 0, "Should be clear.");
 910   reset_for_par_iteration();
 911 }
 912 
 913 void HeapRegionRemSet::reset_for_par_iteration() {
 914   _iter_state = Unclaimed;
 915   _iter_claimed = 0;
 916   // It's good to check this to make sure that the two methods are in sync.
 917   assert(verify_ready_for_par_iteration(), "post-condition");
 918 }
 919 
 920 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
 921                              BitMap* region_bm, BitMap* card_bm) {
 922   _other_regions.scrub(ctbs, region_bm, card_bm);
 923 }
 924 
 925 // Code roots support
 926 
 927 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
 928   assert(nm != NULL, "sanity");
 929   _code_roots.add(nm);
 930 }
 931 
 932 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
 933   assert(nm != NULL, "sanity");
 934   assert_locked_or_safepoint(CodeCache_lock);
 935 
 936   _code_roots.remove_lock_free(nm);
 937 
 938   // Check that there were no duplicates
 939   guarantee(!_code_roots.contains(nm), "duplicate entry found");
 940 }
 941 
 942 class NMethodMigrationOopClosure : public OopClosure {
 943   G1CollectedHeap* _g1h;
 944   HeapRegion* _from;
 945   nmethod* _nm;
 946 
 947   uint _num_self_forwarded;
 948 
 949   template <class T> void do_oop_work(T* p) {
 950     T heap_oop = oopDesc::load_heap_oop(p);
 951     if (!oopDesc::is_null(heap_oop)) {
 952       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
 953       if (_from->is_in(obj)) {
 954         // Reference still points into the source region.
 955         // Since roots are immediately evacuated this means that
 956         // we must have self forwarded the object
 957         assert(obj->is_forwarded(),
 958                err_msg("code roots should be immediately evacuated. "
 959                        "Ref: "PTR_FORMAT", "
 960                        "Obj: "PTR_FORMAT", "
 961                        "Region: "HR_FORMAT,
 962                        p, (void*) obj, HR_FORMAT_PARAMS(_from)));
 963         assert(obj->forwardee() == obj,
 964                err_msg("not self forwarded? obj = "PTR_FORMAT, (void*)obj));
 965 
 966         // The object has been self forwarded.
 967         // Note, if we're during an initial mark pause, there is
 968         // no need to explicitly mark object. It will be marked
 969         // during the regular evacuation failure handling code.
 970         _num_self_forwarded++;
 971       } else {
 972         // The reference points into a promotion or to-space region
 973         HeapRegion* to = _g1h->heap_region_containing(obj);
 974         to->rem_set()->add_strong_code_root(_nm);
 975       }
 976     }
 977   }
 978 
 979 public:
 980   NMethodMigrationOopClosure(G1CollectedHeap* g1h, HeapRegion* from, nmethod* nm):
 981     _g1h(g1h), _from(from), _nm(nm), _num_self_forwarded(0) {}
 982 
 983   void do_oop(narrowOop* p) { do_oop_work(p); }
 984   void do_oop(oop* p)       { do_oop_work(p); }
 985 
 986   uint retain() { return _num_self_forwarded > 0; }
 987 };
 988 
 989 void HeapRegionRemSet::migrate_strong_code_roots() {
 990   assert(hr()->in_collection_set(), "only collection set regions");
 991   assert(!hr()->isHumongous(),
 992          err_msg("humongous region "HR_FORMAT" should not have been added to the collection set",
 993                  HR_FORMAT_PARAMS(hr())));
 994 
 995   ResourceMark rm;
 996 
 997   // List of code blobs to retain for this region
 998   GrowableArray<nmethod*> to_be_retained(10);
 999   G1CollectedHeap* g1h = G1CollectedHeap::heap();
1000 
1001   while (!_code_roots.is_empty()) {
1002     nmethod *nm = _code_roots.pop();
1003     if (nm != NULL) {
1004       NMethodMigrationOopClosure oop_cl(g1h, hr(), nm);
1005       nm->oops_do(&oop_cl);
1006       if (oop_cl.retain()) {
1007         to_be_retained.push(nm);
1008       }
1009     }
1010   }
1011 
1012   // Now push any code roots we need to retain
1013   assert(to_be_retained.is_empty() || hr()->evacuation_failed(),
1014          "Retained nmethod list must be empty or "
1015          "evacuation of this region failed");
1016 
1017   while (to_be_retained.is_nonempty()) {
1018     nmethod* nm = to_be_retained.pop();
1019     assert(nm != NULL, "sanity");
1020     add_strong_code_root(nm);
1021   }
1022 }
1023 
1024 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
1025   _code_roots.nmethods_do(blk);
1026 }
1027 
1028 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
1029   return _code_roots.mem_size();
1030 }
1031 
1032 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
1033   _hrrs(hrrs),
1034   _g1h(G1CollectedHeap::heap()),
1035   _coarse_map(&hrrs->_other_regions._coarse_map),
1036   _bosa(hrrs->bosa()),
1037   _is(Sparse),
1038   // Set these values so that we increment to the first region.
1039   _coarse_cur_region_index(-1),
1040   _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
1041   _cur_card_in_prt(HeapRegion::CardsPerRegion),
1042   _fine_cur_prt(NULL),
1043   _n_yielded_coarse(0),
1044   _n_yielded_fine(0),
1045   _n_yielded_sparse(0),
1046   _sparse_iter(&hrrs->_other_regions._sparse_table) {}
1047 
1048 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
1049   if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
1050   // Go to the next card.
1051   _coarse_cur_region_cur_card++;
1052   // Was the last the last card in the current region?
1053   if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
1054     // Yes: find the next region.  This may leave _coarse_cur_region_index
1055     // Set to the last index, in which case there are no more coarse
1056     // regions.
1057     _coarse_cur_region_index =
1058       (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
1059     if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
1060       _coarse_cur_region_cur_card = 0;
1061       HeapWord* r_bot =
1062         _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
1063       _cur_region_card_offset = _bosa->index_for(r_bot);
1064     } else {
1065       return false;
1066     }
1067   }
1068   // If we didn't return false above, then we can yield a card.
1069   card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
1070   return true;
1071 }
1072 
1073 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
1074   if (fine_has_next()) {
1075     _cur_card_in_prt =
1076       _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1077   }
1078   if (_cur_card_in_prt == HeapRegion::CardsPerRegion) {
1079     // _fine_cur_prt may still be NULL in case if there are not PRTs at all for
1080     // the remembered set.
1081     if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) {
1082       return false;
1083     }
1084     PerRegionTable* next_prt = _fine_cur_prt->next();
1085     switch_to_prt(next_prt);
1086     _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1087   }
1088 
1089   card_index = _cur_region_card_offset + _cur_card_in_prt;
1090   guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion,
1091             err_msg("Card index "SIZE_FORMAT" must be within the region", _cur_card_in_prt));
1092   return true;
1093 }
1094 
1095 bool HeapRegionRemSetIterator::fine_has_next() {
1096   return _cur_card_in_prt != HeapRegion::CardsPerRegion;
1097 }
1098 
1099 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) {
1100   assert(prt != NULL, "Cannot switch to NULL prt");
1101   _fine_cur_prt = prt;
1102 
1103   HeapWord* r_bot = _fine_cur_prt->hr()->bottom();
1104   _cur_region_card_offset = _bosa->index_for(r_bot);
1105 
1106   // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1.
1107   // To avoid special-casing this start case, and not miss the first bitmap
1108   // entry, initialize _cur_region_cur_card with -1 instead of 0.
1109   _cur_card_in_prt = (size_t)-1;
1110 }
1111 
1112 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
1113   switch (_is) {
1114   case Sparse: {
1115     if (_sparse_iter.has_next(card_index)) {
1116       _n_yielded_sparse++;
1117       return true;
1118     }
1119     // Otherwise, deliberate fall-through
1120     _is = Fine;
1121     PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts;
1122     if (initial_fine_prt != NULL) {
1123       switch_to_prt(_hrrs->_other_regions._first_all_fine_prts);
1124     }
1125   }
1126   case Fine:
1127     if (fine_has_next(card_index)) {
1128       _n_yielded_fine++;
1129       return true;
1130     }
1131     // Otherwise, deliberate fall-through
1132     _is = Coarse;
1133   case Coarse:
1134     if (coarse_has_next(card_index)) {
1135       _n_yielded_coarse++;
1136       return true;
1137     }
1138     // Otherwise...
1139     break;
1140   }
1141   assert(ParallelGCThreads > 1 ||
1142          n_yielded() == _hrrs->occupied(),
1143          "Should have yielded all the cards in the rem set "
1144          "(in the non-par case).");
1145   return false;
1146 }
1147 
1148 
1149 
1150 OopOrNarrowOopStar* HeapRegionRemSet::_recorded_oops = NULL;
1151 HeapWord**          HeapRegionRemSet::_recorded_cards = NULL;
1152 HeapRegion**        HeapRegionRemSet::_recorded_regions = NULL;
1153 int                 HeapRegionRemSet::_n_recorded = 0;
1154 
1155 HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
1156 int*         HeapRegionRemSet::_recorded_event_index = NULL;
1157 int          HeapRegionRemSet::_n_recorded_events = 0;
1158 
1159 void HeapRegionRemSet::record(HeapRegion* hr, OopOrNarrowOopStar f) {
1160   if (_recorded_oops == NULL) {
1161     assert(_n_recorded == 0
1162            && _recorded_cards == NULL
1163            && _recorded_regions == NULL,
1164            "Inv");
1165     _recorded_oops    = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
1166     _recorded_cards   = NEW_C_HEAP_ARRAY(HeapWord*,          MaxRecorded, mtGC);
1167     _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*,        MaxRecorded, mtGC);
1168   }
1169   if (_n_recorded == MaxRecorded) {
1170     gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
1171   } else {
1172     _recorded_cards[_n_recorded] =
1173       (HeapWord*)align_size_down(uintptr_t(f),
1174                                  CardTableModRefBS::card_size);
1175     _recorded_oops[_n_recorded] = f;
1176     _recorded_regions[_n_recorded] = hr;
1177     _n_recorded++;
1178   }
1179 }
1180 
1181 void HeapRegionRemSet::record_event(Event evnt) {
1182   if (!G1RecordHRRSEvents) return;
1183 
1184   if (_recorded_events == NULL) {
1185     assert(_n_recorded_events == 0
1186            && _recorded_event_index == NULL,
1187            "Inv");
1188     _recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents, mtGC);
1189     _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
1190   }
1191   if (_n_recorded_events == MaxRecordedEvents) {
1192     gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
1193   } else {
1194     _recorded_events[_n_recorded_events] = evnt;
1195     _recorded_event_index[_n_recorded_events] = _n_recorded;
1196     _n_recorded_events++;
1197   }
1198 }
1199 
1200 void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
1201   switch (evnt) {
1202   case Event_EvacStart:
1203     str->print("Evac Start");
1204     break;
1205   case Event_EvacEnd:
1206     str->print("Evac End");
1207     break;
1208   case Event_RSUpdateEnd:
1209     str->print("RS Update End");
1210     break;
1211   }
1212 }
1213 
1214 void HeapRegionRemSet::print_recorded() {
1215   int cur_evnt = 0;
1216   Event cur_evnt_kind;
1217   int cur_evnt_ind = 0;
1218   if (_n_recorded_events > 0) {
1219     cur_evnt_kind = _recorded_events[cur_evnt];
1220     cur_evnt_ind = _recorded_event_index[cur_evnt];
1221   }
1222 
1223   for (int i = 0; i < _n_recorded; i++) {
1224     while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
1225       gclog_or_tty->print("Event: ");
1226       print_event(gclog_or_tty, cur_evnt_kind);
1227       gclog_or_tty->cr();
1228       cur_evnt++;
1229       if (cur_evnt < MaxRecordedEvents) {
1230         cur_evnt_kind = _recorded_events[cur_evnt];
1231         cur_evnt_ind = _recorded_event_index[cur_evnt];
1232       }
1233     }
1234     gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
1235                         " for ref " PTR_FORMAT ".\n",
1236                         _recorded_cards[i], _recorded_regions[i]->bottom(),
1237                         _recorded_oops[i]);
1238   }
1239 }
1240 
1241 void HeapRegionRemSet::reset_for_cleanup_tasks() {
1242   SparsePRT::reset_for_cleanup_tasks();
1243 }
1244 
1245 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
1246   _other_regions.do_cleanup_work(hrrs_cleanup_task);
1247 }
1248 
1249 void
1250 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
1251   SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
1252 }
1253 
1254 #ifndef PRODUCT
1255 void PerRegionTable::test_fl_mem_size() {
1256   PerRegionTable* dummy = alloc(NULL);
1257 
1258   size_t min_prt_size = sizeof(void*) + dummy->bm()->size_in_words() * HeapWordSize;
1259   assert(dummy->mem_size() > min_prt_size,
1260          err_msg("PerRegionTable memory usage is suspiciously small, only has "SIZE_FORMAT" bytes. "
1261                  "Should be at least "SIZE_FORMAT" bytes.", dummy->mem_size(), min_prt_size));
1262   free(dummy);
1263   guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
1264   // try to reset the state
1265   _free_list = NULL;
1266   delete dummy;
1267 }
1268 
1269 void HeapRegionRemSet::test_prt() {
1270   PerRegionTable::test_fl_mem_size();
1271 }
1272 
1273 void HeapRegionRemSet::test() {
1274   os::sleep(Thread::current(), (jlong)5000, false);
1275   G1CollectedHeap* g1h = G1CollectedHeap::heap();
1276 
1277   // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
1278   // hash bucket.
1279   HeapRegion* hr0 = g1h->region_at(0);
1280   HeapRegion* hr1 = g1h->region_at(1);
1281   HeapRegion* hr2 = g1h->region_at(5);
1282   HeapRegion* hr3 = g1h->region_at(6);
1283   HeapRegion* hr4 = g1h->region_at(7);
1284   HeapRegion* hr5 = g1h->region_at(8);
1285 
1286   HeapWord* hr1_start = hr1->bottom();
1287   HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
1288   HeapWord* hr1_last = hr1->end() - 1;
1289 
1290   HeapWord* hr2_start = hr2->bottom();
1291   HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
1292   HeapWord* hr2_last = hr2->end() - 1;
1293 
1294   HeapWord* hr3_start = hr3->bottom();
1295   HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
1296   HeapWord* hr3_last = hr3->end() - 1;
1297 
1298   HeapRegionRemSet* hrrs = hr0->rem_set();
1299 
1300   // Make three references from region 0x101...
1301   hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
1302   hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
1303   hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
1304 
1305   hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
1306   hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
1307   hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
1308 
1309   hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
1310   hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
1311   hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
1312 
1313   // Now cause a coarsening.
1314   hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
1315   hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
1316 
1317   // Now, does iteration yield these three?
1318   HeapRegionRemSetIterator iter(hrrs);
1319   size_t sum = 0;
1320   size_t card_index;
1321   while (iter.has_next(card_index)) {
1322     HeapWord* card_start =
1323       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
1324     gclog_or_tty->print_cr("  Card " PTR_FORMAT ".", card_start);
1325     sum++;
1326   }
1327   guarantee(sum == 11 - 3 + 2048, "Failure");
1328   guarantee(sum == hrrs->occupied(), "Failure");
1329 }
1330 #endif