1 /*
   2  * Copyright (c) 2001, 2018, 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/heapRegionManager.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 "utilities/bitMap.inline.hpp"
  36 #include "utilities/globalDefinitions.hpp"
  37 #include "utilities/growableArray.hpp"
  38 
  39 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  40 
  41 class PerRegionTable: public CHeapObj<mtGC> {
  42   friend class OtherRegionsTable;
  43   friend class HeapRegionRemSetIterator;
  44 
  45   HeapRegion*     _hr;
  46   BitMap          _bm;
  47   jint            _occupied;
  48 
  49   // next pointer for free/allocated 'all' list
  50   PerRegionTable* _next;
  51 
  52   // prev pointer for the allocated 'all' list
  53   PerRegionTable* _prev;
  54 
  55   // next pointer in collision list
  56   PerRegionTable * _collision_list_next;
  57 
  58   // Global free list of PRTs
  59   static PerRegionTable* _free_list;
  60 
  61 protected:
  62   // We need access in order to union things into the base table.
  63   BitMap* bm() { return &_bm; }
  64 
  65   void recount_occupied() {
  66     _occupied = (jint) bm()->count_one_bits();
  67   }
  68 
  69   PerRegionTable(HeapRegion* hr) :
  70     _hr(hr),
  71     _occupied(0),
  72     _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */),
  73     _collision_list_next(NULL), _next(NULL), _prev(NULL)
  74   {}
  75 
  76   void add_card_work(CardIdx_t from_card, bool par) {
  77     if (!_bm.at(from_card)) {
  78       if (par) {
  79         if (_bm.par_at_put(from_card, 1)) {
  80           Atomic::inc(&_occupied);
  81         }
  82       } else {
  83         _bm.at_put(from_card, 1);
  84         _occupied++;
  85       }
  86     }
  87   }
  88 
  89   void add_reference_work(OopOrNarrowOopStar from, bool par) {
  90     // Must make this robust in case "from" is not in "_hr", because of
  91     // concurrency.
  92 
  93     if (G1TraceHeapRegionRememberedSet) {
  94       gclog_or_tty->print_cr("    PRT::Add_reference_work(" PTR_FORMAT "->" PTR_FORMAT").",
  95                              from,
  96                              UseCompressedOops
  97                              ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
  98                              : (void *)oopDesc::load_decode_heap_oop((oop*)from));
  99     }
 100 
 101     HeapRegion* loc_hr = hr();
 102     // If the test below fails, then this table was reused concurrently
 103     // with this operation.  This is OK, since the old table was coarsened,
 104     // and adding a bit to the new table is never incorrect.
 105     // If the table used to belong to a continues humongous region and is
 106     // now reused for the corresponding start humongous region, we need to
 107     // make sure that we detect this. Thus, we call is_in_reserved_raw()
 108     // instead of just is_in_reserved() here.
 109     if (loc_hr->is_in_reserved_raw(from)) {
 110       size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom());
 111       CardIdx_t from_card = (CardIdx_t)
 112           hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize);
 113 
 114       assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion,
 115              "Must be in range.");
 116       add_card_work(from_card, par);
 117     }
 118   }
 119 
 120 public:
 121 
 122   HeapRegion* hr() const {
 123     return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr);
 124   }
 125 
 126   jint occupied() const {
 127     // Overkill, but if we ever need it...
 128     // guarantee(_occupied == _bm.count_one_bits(), "Check");
 129     return _occupied;
 130   }
 131 
 132   void init(HeapRegion* hr, bool clear_links_to_all_list) {
 133     if (clear_links_to_all_list) {
 134       set_next(NULL);
 135       set_prev(NULL);
 136     }
 137     _collision_list_next = NULL;
 138     _occupied = 0;
 139     _bm.clear();
 140     // Make sure that the bitmap clearing above has been finished before publishing
 141     // this PRT to concurrent threads.
 142     OrderAccess::release_store_ptr(&_hr, hr);
 143   }
 144 
 145   void add_reference(OopOrNarrowOopStar from) {
 146     add_reference_work(from, /*parallel*/ true);
 147   }
 148 
 149   void seq_add_reference(OopOrNarrowOopStar from) {
 150     add_reference_work(from, /*parallel*/ false);
 151   }
 152 
 153   void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) {
 154     HeapWord* hr_bot = hr()->bottom();
 155     size_t hr_first_card_index = ctbs->index_for(hr_bot);
 156     bm()->set_intersection_at_offset(*card_bm, hr_first_card_index);
 157     recount_occupied();
 158   }
 159 
 160   void add_card(CardIdx_t from_card_index) {
 161     add_card_work(from_card_index, /*parallel*/ true);
 162   }
 163 
 164   void seq_add_card(CardIdx_t from_card_index) {
 165     add_card_work(from_card_index, /*parallel*/ false);
 166   }
 167 
 168   // (Destructively) union the bitmap of the current table into the given
 169   // bitmap (which is assumed to be of the same size.)
 170   void union_bitmap_into(BitMap* bm) {
 171     bm->set_union(_bm);
 172   }
 173 
 174   // Mem size in bytes.
 175   size_t mem_size() const {
 176     return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize;
 177   }
 178 
 179   // Requires "from" to be in "hr()".
 180   bool contains_reference(OopOrNarrowOopStar from) const {
 181     assert(hr()->is_in_reserved(from), "Precondition.");
 182     size_t card_ind = pointer_delta(from, hr()->bottom(),
 183                                     CardTableModRefBS::card_size);
 184     return _bm.at(card_ind);
 185   }
 186 
 187   // Bulk-free the PRTs from prt to last, assumes that they are
 188   // linked together using their _next field.
 189   static void bulk_free(PerRegionTable* prt, PerRegionTable* last) {
 190     while (true) {
 191       PerRegionTable* fl = _free_list;
 192       last->set_next(fl);
 193       PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl);
 194       if (res == fl) {
 195         return;
 196       }
 197     }
 198     ShouldNotReachHere();
 199   }
 200 
 201   static void free(PerRegionTable* prt) {
 202     bulk_free(prt, prt);
 203   }
 204 
 205   // Returns an initialized PerRegionTable instance.
 206   static PerRegionTable* alloc(HeapRegion* hr) {
 207     PerRegionTable* fl = _free_list;
 208     while (fl != NULL) {
 209       PerRegionTable* nxt = fl->next();
 210       PerRegionTable* res =
 211         (PerRegionTable*)
 212         Atomic::cmpxchg_ptr(nxt, &_free_list, fl);
 213       if (res == fl) {
 214         fl->init(hr, true);
 215         return fl;
 216       } else {
 217         fl = _free_list;
 218       }
 219     }
 220     assert(fl == NULL, "Loop condition.");
 221     return new PerRegionTable(hr);
 222   }
 223 
 224   PerRegionTable* next() const { return _next; }
 225   void set_next(PerRegionTable* next) { _next = next; }
 226   PerRegionTable* prev() const { return _prev; }
 227   void set_prev(PerRegionTable* prev) { _prev = prev; }
 228 
 229   // Accessor and Modification routines for the pointer for the
 230   // singly linked collision list that links the PRTs within the
 231   // OtherRegionsTable::_fine_grain_regions hash table.
 232   //
 233   // It might be useful to also make the collision list doubly linked
 234   // to avoid iteration over the collisions list during scrubbing/deletion.
 235   // OTOH there might not be many collisions.
 236 
 237   PerRegionTable* collision_list_next() const {
 238     return _collision_list_next;
 239   }
 240 
 241   void set_collision_list_next(PerRegionTable* next) {
 242     _collision_list_next = next;
 243   }
 244 
 245   PerRegionTable** collision_list_next_addr() {
 246     return &_collision_list_next;
 247   }
 248 
 249   static size_t fl_mem_size() {
 250     PerRegionTable* cur = _free_list;
 251     size_t res = 0;
 252     while (cur != NULL) {
 253       res += cur->mem_size();
 254       cur = cur->next();
 255     }
 256     return res;
 257   }
 258 
 259   static void test_fl_mem_size();
 260 };
 261 
 262 PerRegionTable* PerRegionTable::_free_list = NULL;
 263 
 264 size_t OtherRegionsTable::_max_fine_entries = 0;
 265 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0;
 266 size_t OtherRegionsTable::_fine_eviction_stride = 0;
 267 size_t OtherRegionsTable::_fine_eviction_sample_size = 0;
 268 
 269 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) :
 270   _g1h(G1CollectedHeap::heap()),
 271   _hr(hr), _m(m),
 272   _coarse_map(G1CollectedHeap::heap()->max_regions(),
 273               false /* in-resource-area */),
 274   _fine_grain_regions(NULL),
 275   _first_all_fine_prts(NULL), _last_all_fine_prts(NULL),
 276   _n_fine_entries(0), _n_coarse_entries(0),
 277   _fine_eviction_start(0),
 278   _sparse_table(hr)
 279 {
 280   typedef PerRegionTable* PerRegionTablePtr;
 281 
 282   if (_max_fine_entries == 0) {
 283     assert(_mod_max_fine_entries_mask == 0, "Both or none.");
 284     size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries);
 285     _max_fine_entries = (size_t)1 << max_entries_log;
 286     _mod_max_fine_entries_mask = _max_fine_entries - 1;
 287 
 288     assert(_fine_eviction_sample_size == 0
 289            && _fine_eviction_stride == 0, "All init at same time.");
 290     _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log);
 291     _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size;
 292   }
 293 
 294   _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries,
 295                         mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
 296 
 297   if (_fine_grain_regions == NULL) {
 298     vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR,
 299                           "Failed to allocate _fine_grain_entries.");
 300   }
 301 
 302   for (size_t i = 0; i < _max_fine_entries; i++) {
 303     _fine_grain_regions[i] = NULL;
 304   }
 305 }
 306 
 307 void OtherRegionsTable::link_to_all(PerRegionTable* prt) {
 308   // We always append to the beginning of the list for convenience;
 309   // the order of entries in this list does not matter.
 310   if (_first_all_fine_prts != NULL) {
 311     assert(_first_all_fine_prts->prev() == NULL, "invariant");
 312     _first_all_fine_prts->set_prev(prt);
 313     prt->set_next(_first_all_fine_prts);
 314   } else {
 315     // this is the first element we insert. Adjust the "last" pointer
 316     _last_all_fine_prts = prt;
 317     assert(prt->next() == NULL, "just checking");
 318   }
 319   // the new element is always the first element without a predecessor
 320   prt->set_prev(NULL);
 321   _first_all_fine_prts = prt;
 322 
 323   assert(prt->prev() == NULL, "just checking");
 324   assert(_first_all_fine_prts == prt, "just checking");
 325   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
 326          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
 327          "just checking");
 328   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
 329          "just checking");
 330   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
 331          "just checking");
 332 }
 333 
 334 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) {
 335   if (prt->prev() != NULL) {
 336     assert(_first_all_fine_prts != prt, "just checking");
 337     prt->prev()->set_next(prt->next());
 338     // removing the last element in the list?
 339     if (_last_all_fine_prts == prt) {
 340       _last_all_fine_prts = prt->prev();
 341     }
 342   } else {
 343     assert(_first_all_fine_prts == prt, "just checking");
 344     _first_all_fine_prts = prt->next();
 345     // list is empty now?
 346     if (_first_all_fine_prts == NULL) {
 347       _last_all_fine_prts = NULL;
 348     }
 349   }
 350 
 351   if (prt->next() != NULL) {
 352     prt->next()->set_prev(prt->prev());
 353   }
 354 
 355   prt->set_next(NULL);
 356   prt->set_prev(NULL);
 357 
 358   assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) ||
 359          (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL),
 360          "just checking");
 361   assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL,
 362          "just checking");
 363   assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL,
 364          "just checking");
 365 }
 366 
 367 int**  FromCardCache::_cache = NULL;
 368 uint   FromCardCache::_max_regions = 0;
 369 size_t FromCardCache::_static_mem_size = 0;
 370 
 371 void FromCardCache::initialize(uint n_par_rs, uint max_num_regions) {
 372   guarantee(_cache == NULL, "Should not call this multiple times");
 373 
 374   _max_regions = max_num_regions;
 375   _cache = Padded2DArray<int, mtGC>::create_unfreeable(n_par_rs,
 376                                                        _max_regions,
 377                                                        &_static_mem_size);
 378 
 379   invalidate(0, _max_regions);
 380 }
 381 
 382 void FromCardCache::invalidate(uint start_idx, size_t new_num_regions) {
 383   guarantee((size_t)start_idx + new_num_regions <= max_uintx,
 384             err_msg("Trying to invalidate beyond maximum region, from %u size " SIZE_FORMAT,
 385                     start_idx, new_num_regions));
 386   for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
 387     uint end_idx = (start_idx + (uint)new_num_regions);
 388     assert(end_idx <= _max_regions, "Must be within max.");
 389     for (uint j = start_idx; j < end_idx; j++) {
 390       set(i, j, InvalidCard);
 391     }
 392   }
 393 }
 394 
 395 #ifndef PRODUCT
 396 void FromCardCache::print(outputStream* out) {
 397   for (uint i = 0; i < HeapRegionRemSet::num_par_rem_sets(); i++) {
 398     for (uint j = 0; j < _max_regions; j++) {
 399       out->print_cr("_from_card_cache[" UINT32_FORMAT "][" UINT32_FORMAT "] = " INT32_FORMAT ".",
 400                     i, j, at(i, j));
 401     }
 402   }
 403 }
 404 #endif
 405 
 406 void FromCardCache::clear(uint region_idx) {
 407   uint num_par_remsets = HeapRegionRemSet::num_par_rem_sets();
 408   for (uint i = 0; i < num_par_remsets; i++) {
 409     set(i, region_idx, InvalidCard);
 410   }
 411 }
 412 
 413 void OtherRegionsTable::initialize(uint max_regions) {
 414   FromCardCache::initialize(HeapRegionRemSet::num_par_rem_sets(), max_regions);
 415 }
 416 
 417 void OtherRegionsTable::invalidate(uint start_idx, size_t num_regions) {
 418   FromCardCache::invalidate(start_idx, num_regions);
 419 }
 420 
 421 void OtherRegionsTable::print_from_card_cache() {
 422   FromCardCache::print();
 423 }
 424 
 425 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, int tid) {
 426   uint cur_hrm_ind = hr()->hrm_index();
 427 
 428   if (G1TraceHeapRegionRememberedSet) {
 429     gclog_or_tty->print_cr("ORT::add_reference_work(" PTR_FORMAT "->" PTR_FORMAT ").",
 430                                                     from,
 431                                                     UseCompressedOops
 432                                                     ? (void *)oopDesc::load_decode_heap_oop((narrowOop*)from)
 433                                                     : (void *)oopDesc::load_decode_heap_oop((oop*)from));
 434   }
 435 
 436   int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift);
 437 
 438   if (G1TraceHeapRegionRememberedSet) {
 439     gclog_or_tty->print_cr("Table for [" PTR_FORMAT "...): card %d (cache = " INT32_FORMAT ")",
 440                   hr()->bottom(), from_card,
 441                   FromCardCache::at((uint)tid, cur_hrm_ind));
 442   }
 443 
 444   if (FromCardCache::contains_or_replace((uint)tid, cur_hrm_ind, from_card)) {
 445     if (G1TraceHeapRegionRememberedSet) {
 446       gclog_or_tty->print_cr("  from-card cache hit.");
 447     }
 448     assert(contains_reference(from), err_msg("We just found " PTR_FORMAT " in the FromCardCache", from));
 449     return;
 450   }
 451 
 452   // Note that this may be a continued H region.
 453   HeapRegion* from_hr = _g1h->heap_region_containing_raw(from);
 454   RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index();
 455 
 456   // If the region is already coarsened, return.
 457   if (_coarse_map.at(from_hrm_ind)) {
 458     if (G1TraceHeapRegionRememberedSet) {
 459       gclog_or_tty->print_cr("  coarse map hit.");
 460     }
 461     assert(contains_reference(from), err_msg("We just found " PTR_FORMAT " in the Coarse table", from));
 462     return;
 463   }
 464 
 465   // Otherwise find a per-region table to add it to.
 466   size_t ind = from_hrm_ind & _mod_max_fine_entries_mask;
 467   PerRegionTable* prt = find_region_table(ind, from_hr);
 468   if (prt == NULL) {
 469     MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag);
 470     // Confirm that it's really not there...
 471     prt = find_region_table(ind, from_hr);
 472     if (prt == NULL) {
 473 
 474       uintptr_t from_hr_bot_card_index =
 475         uintptr_t(from_hr->bottom())
 476           >> CardTableModRefBS::card_shift;
 477       CardIdx_t card_index = from_card - from_hr_bot_card_index;
 478       assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
 479              "Must be in range.");
 480       if (G1HRRSUseSparseTable &&
 481           _sparse_table.add_card(from_hrm_ind, card_index)) {
 482         if (G1RecordHRRSOops) {
 483           HeapRegionRemSet::record(hr(), from);
 484           if (G1TraceHeapRegionRememberedSet) {
 485             gclog_or_tty->print("   Added card " PTR_FORMAT " to region "
 486                                 "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
 487                                 align_size_down(uintptr_t(from),
 488                                                 CardTableModRefBS::card_size),
 489                                 hr()->bottom(), from);
 490           }
 491         }
 492         if (G1TraceHeapRegionRememberedSet) {
 493           gclog_or_tty->print_cr("   added card to sparse table.");
 494         }
 495         assert(contains_reference_locked(from), err_msg("We just added " PTR_FORMAT " to the Sparse table", from));
 496         return;
 497       } else {
 498         if (G1TraceHeapRegionRememberedSet) {
 499           gclog_or_tty->print_cr("   [tid %d] sparse table entry "
 500                         "overflow(f: %d, t: %u)",
 501                         tid, from_hrm_ind, cur_hrm_ind);
 502         }
 503       }
 504 
 505       if (_n_fine_entries == _max_fine_entries) {
 506         prt = delete_region_table();
 507         // There is no need to clear the links to the 'all' list here:
 508         // prt will be reused immediately, i.e. remain in the 'all' list.
 509         prt->init(from_hr, false /* clear_links_to_all_list */);
 510       } else {
 511         prt = PerRegionTable::alloc(from_hr);
 512         link_to_all(prt);
 513       }
 514 
 515       PerRegionTable* first_prt = _fine_grain_regions[ind];
 516       prt->set_collision_list_next(first_prt);
 517       // The assignment into _fine_grain_regions allows the prt to
 518       // start being used concurrently. In addition to
 519       // collision_list_next which must be visible (else concurrent
 520       // parsing of the list, if any, may fail to see other entries),
 521       // the content of the prt must be visible (else for instance
 522       // some mark bits may not yet seem cleared or a 'later' update
 523       // performed by a concurrent thread could be undone when the
 524       // zeroing becomes visible). This requires store ordering.
 525       OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt);
 526       _n_fine_entries++;
 527 
 528       if (G1HRRSUseSparseTable) {
 529         // Transfer from sparse to fine-grain.
 530         SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind);
 531         assert(sprt_entry != NULL, "There should have been an entry");
 532         for (int i = 0; i < SparsePRTEntry::cards_num(); i++) {
 533           CardIdx_t c = sprt_entry->card(i);
 534           if (c != SparsePRTEntry::NullEntry) {
 535             prt->add_card(c);
 536           }
 537         }
 538         // Now we can delete the sparse entry.
 539         bool res = _sparse_table.delete_entry(from_hrm_ind);
 540         assert(res, "It should have been there.");
 541       }
 542     }
 543     assert(prt != NULL && prt->hr() == from_hr, "consequence");
 544   }
 545   // Note that we can't assert "prt->hr() == from_hr", because of the
 546   // possibility of concurrent reuse.  But see head comment of
 547   // OtherRegionsTable for why this is OK.
 548   assert(prt != NULL, "Inv");
 549 
 550   prt->add_reference(from);
 551 
 552   if (G1RecordHRRSOops) {
 553     HeapRegionRemSet::record(hr(), from);
 554     if (G1TraceHeapRegionRememberedSet) {
 555       gclog_or_tty->print("Added card " PTR_FORMAT " to region "
 556                           "[" PTR_FORMAT "...) for ref " PTR_FORMAT ".\n",
 557                           align_size_down(uintptr_t(from),
 558                                           CardTableModRefBS::card_size),
 559                           hr()->bottom(), from);
 560     }
 561   }
 562   assert(contains_reference(from), err_msg("We just added " PTR_FORMAT " to the PRT", from));
 563 }
 564 
 565 PerRegionTable*
 566 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const {
 567   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
 568   PerRegionTable* prt = _fine_grain_regions[ind];
 569   while (prt != NULL && prt->hr() != hr) {
 570     prt = prt->collision_list_next();
 571   }
 572   // Loop postcondition is the method postcondition.
 573   return prt;
 574 }
 575 
 576 jint OtherRegionsTable::_n_coarsenings = 0;
 577 
 578 PerRegionTable* OtherRegionsTable::delete_region_table() {
 579   assert(_m->owned_by_self(), "Precondition");
 580   assert(_n_fine_entries == _max_fine_entries, "Precondition");
 581   PerRegionTable* max = NULL;
 582   jint max_occ = 0;
 583   PerRegionTable** max_prev = NULL;
 584   size_t max_ind;
 585 
 586   size_t i = _fine_eviction_start;
 587   for (size_t k = 0; k < _fine_eviction_sample_size; k++) {
 588     size_t ii = i;
 589     // Make sure we get a non-NULL sample.
 590     while (_fine_grain_regions[ii] == NULL) {
 591       ii++;
 592       if (ii == _max_fine_entries) ii = 0;
 593       guarantee(ii != i, "We must find one.");
 594     }
 595     PerRegionTable** prev = &_fine_grain_regions[ii];
 596     PerRegionTable* cur = *prev;
 597     while (cur != NULL) {
 598       jint cur_occ = cur->occupied();
 599       if (max == NULL || cur_occ > max_occ) {
 600         max = cur;
 601         max_prev = prev;
 602         max_ind = i;
 603         max_occ = cur_occ;
 604       }
 605       prev = cur->collision_list_next_addr();
 606       cur = cur->collision_list_next();
 607     }
 608     i = i + _fine_eviction_stride;
 609     if (i >= _n_fine_entries) i = i - _n_fine_entries;
 610   }
 611 
 612   _fine_eviction_start++;
 613 
 614   if (_fine_eviction_start >= _n_fine_entries) {
 615     _fine_eviction_start -= _n_fine_entries;
 616   }
 617 
 618   guarantee(max != NULL, "Since _n_fine_entries > 0");
 619   guarantee(max_prev != NULL, "Since max != NULL.");
 620 
 621   // Set the corresponding coarse bit.
 622   size_t max_hrm_index = (size_t) max->hr()->hrm_index();
 623   if (!_coarse_map.at(max_hrm_index)) {
 624     _coarse_map.at_put(max_hrm_index, true);
 625     _n_coarse_entries++;
 626     if (G1TraceHeapRegionRememberedSet) {
 627       gclog_or_tty->print("Coarsened entry in region [" PTR_FORMAT "...] "
 628                  "for region [" PTR_FORMAT "...] (%d coarse entries).\n",
 629                  hr()->bottom(),
 630                  max->hr()->bottom(),
 631                  _n_coarse_entries);
 632     }
 633   }
 634 
 635   // Unsplice.
 636   *max_prev = max->collision_list_next();
 637   Atomic::inc(&_n_coarsenings);
 638   _n_fine_entries--;
 639   return max;
 640 }
 641 
 642 
 643 // At present, this must be called stop-world single-threaded.
 644 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs,
 645                               BitMap* region_bm, BitMap* card_bm) {
 646   // First eliminated garbage regions from the coarse map.
 647   if (G1RSScrubVerbose) {
 648     gclog_or_tty->print_cr("Scrubbing region %u:", hr()->hrm_index());
 649   }
 650 
 651   assert(_coarse_map.size() == region_bm->size(), "Precondition");
 652   if (G1RSScrubVerbose) {
 653     gclog_or_tty->print("   Coarse map: before = " SIZE_FORMAT "...",
 654                         _n_coarse_entries);
 655   }
 656   _coarse_map.set_intersection(*region_bm);
 657   _n_coarse_entries = _coarse_map.count_one_bits();
 658   if (G1RSScrubVerbose) {
 659     gclog_or_tty->print_cr("   after = " SIZE_FORMAT ".", _n_coarse_entries);
 660   }
 661 
 662   // Now do the fine-grained maps.
 663   for (size_t i = 0; i < _max_fine_entries; i++) {
 664     PerRegionTable* cur = _fine_grain_regions[i];
 665     PerRegionTable** prev = &_fine_grain_regions[i];
 666     while (cur != NULL) {
 667       PerRegionTable* nxt = cur->collision_list_next();
 668       // If the entire region is dead, eliminate.
 669       if (G1RSScrubVerbose) {
 670         gclog_or_tty->print_cr("     For other region %u:",
 671                                cur->hr()->hrm_index());
 672       }
 673       if (!region_bm->at((size_t) cur->hr()->hrm_index())) {
 674         *prev = nxt;
 675         cur->set_collision_list_next(NULL);
 676         _n_fine_entries--;
 677         if (G1RSScrubVerbose) {
 678           gclog_or_tty->print_cr("          deleted via region map.");
 679         }
 680         unlink_from_all(cur);
 681         PerRegionTable::free(cur);
 682       } else {
 683         // Do fine-grain elimination.
 684         if (G1RSScrubVerbose) {
 685           gclog_or_tty->print("          occ: before = %4d.", cur->occupied());
 686         }
 687         cur->scrub(ctbs, card_bm);
 688         if (G1RSScrubVerbose) {
 689           gclog_or_tty->print_cr("          after = %4d.", cur->occupied());
 690         }
 691         // Did that empty the table completely?
 692         if (cur->occupied() == 0) {
 693           *prev = nxt;
 694           cur->set_collision_list_next(NULL);
 695           _n_fine_entries--;
 696           unlink_from_all(cur);
 697           PerRegionTable::free(cur);
 698         } else {
 699           prev = cur->collision_list_next_addr();
 700         }
 701       }
 702       cur = nxt;
 703     }
 704   }
 705   // Since we may have deleted a from_card_cache entry from the RS, clear
 706   // the FCC.
 707   clear_fcc();
 708 }
 709 
 710 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const {
 711   if (limit <= (size_t)G1RSetSparseRegionEntries) {
 712     return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit;
 713   } else {
 714     // Current uses of this method may only use values less than G1RSetSparseRegionEntries
 715     // for the limit. The solution, comparing against occupied() would be too slow
 716     // at this time.
 717     Unimplemented();
 718     return false;
 719   }
 720 }
 721 
 722 bool OtherRegionsTable::is_empty() const {
 723   return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL;
 724 }
 725 
 726 size_t OtherRegionsTable::occupied() const {
 727   size_t sum = occ_fine();
 728   sum += occ_sparse();
 729   sum += occ_coarse();
 730   return sum;
 731 }
 732 
 733 size_t OtherRegionsTable::occ_fine() const {
 734   size_t sum = 0;
 735 
 736   size_t num = 0;
 737   PerRegionTable * cur = _first_all_fine_prts;
 738   while (cur != NULL) {
 739     sum += cur->occupied();
 740     cur = cur->next();
 741     num++;
 742   }
 743   guarantee(num == _n_fine_entries, "just checking");
 744   return sum;
 745 }
 746 
 747 size_t OtherRegionsTable::occ_coarse() const {
 748   return (_n_coarse_entries * HeapRegion::CardsPerRegion);
 749 }
 750 
 751 size_t OtherRegionsTable::occ_sparse() const {
 752   return _sparse_table.occupied();
 753 }
 754 
 755 size_t OtherRegionsTable::mem_size() const {
 756   size_t sum = 0;
 757   // all PRTs are of the same size so it is sufficient to query only one of them.
 758   if (_first_all_fine_prts != NULL) {
 759     assert(_last_all_fine_prts != NULL &&
 760       _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant");
 761     sum += _first_all_fine_prts->mem_size() * _n_fine_entries;
 762   }
 763   sum += (sizeof(PerRegionTable*) * _max_fine_entries);
 764   sum += (_coarse_map.size_in_words() * HeapWordSize);
 765   sum += (_sparse_table.mem_size());
 766   sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above.
 767   return sum;
 768 }
 769 
 770 size_t OtherRegionsTable::static_mem_size() {
 771   return FromCardCache::static_mem_size();
 772 }
 773 
 774 size_t OtherRegionsTable::fl_mem_size() {
 775   return PerRegionTable::fl_mem_size();
 776 }
 777 
 778 void OtherRegionsTable::clear_fcc() {
 779   FromCardCache::clear(hr()->hrm_index());
 780 }
 781 
 782 void OtherRegionsTable::clear() {
 783   // if there are no entries, skip this step
 784   if (_first_all_fine_prts != NULL) {
 785     guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking");
 786     PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts);
 787     memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0]));
 788   } else {
 789     guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking");
 790   }
 791 
 792   _first_all_fine_prts = _last_all_fine_prts = NULL;
 793   _sparse_table.clear();
 794   _coarse_map.clear();
 795   _n_fine_entries = 0;
 796   _n_coarse_entries = 0;
 797 
 798   clear_fcc();
 799 }
 800 
 801 bool OtherRegionsTable::del_single_region_table(size_t ind,
 802                                                 HeapRegion* hr) {
 803   assert(0 <= ind && ind < _max_fine_entries, "Preconditions.");
 804   PerRegionTable** prev_addr = &_fine_grain_regions[ind];
 805   PerRegionTable* prt = *prev_addr;
 806   while (prt != NULL && prt->hr() != hr) {
 807     prev_addr = prt->collision_list_next_addr();
 808     prt = prt->collision_list_next();
 809   }
 810   if (prt != NULL) {
 811     assert(prt->hr() == hr, "Loop postcondition.");
 812     *prev_addr = prt->collision_list_next();
 813     unlink_from_all(prt);
 814     PerRegionTable::free(prt);
 815     _n_fine_entries--;
 816     return true;
 817   } else {
 818     return false;
 819   }
 820 }
 821 
 822 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const {
 823   // Cast away const in this case.
 824   MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag);
 825   return contains_reference_locked(from);
 826 }
 827 
 828 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const {
 829   HeapRegion* hr = _g1h->heap_region_containing_raw(from);
 830   RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index();
 831   // Is this region in the coarse map?
 832   if (_coarse_map.at(hr_ind)) return true;
 833 
 834   PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask,
 835                                      hr);
 836   if (prt != NULL) {
 837     return prt->contains_reference(from);
 838 
 839   } else {
 840     uintptr_t from_card =
 841       (uintptr_t(from) >> CardTableModRefBS::card_shift);
 842     uintptr_t hr_bot_card_index =
 843       uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift;
 844     assert(from_card >= hr_bot_card_index, "Inv");
 845     CardIdx_t card_index = from_card - hr_bot_card_index;
 846     assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion,
 847            "Must be in range.");
 848     return _sparse_table.contains_card(hr_ind, card_index);
 849   }
 850 }
 851 
 852 void
 853 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
 854   _sparse_table.do_cleanup_work(hrrs_cleanup_task);
 855 }
 856 
 857 // Determines how many threads can add records to an rset in parallel.
 858 // This can be done by either mutator threads together with the
 859 // concurrent refinement threads or GC threads.
 860 uint HeapRegionRemSet::num_par_rem_sets() {
 861   return MAX2(DirtyCardQueueSet::num_par_ids() + ConcurrentG1Refine::thread_num(), (uint)ParallelGCThreads);
 862 }
 863 
 864 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
 865                                    HeapRegion* hr)
 866   : _bosa(bosa),
 867     _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true),
 868     _code_roots(), _other_regions(hr, &_m), _iter_state(Unclaimed), _iter_claimed(0) {
 869   reset_for_par_iteration();
 870 }
 871 
 872 void HeapRegionRemSet::setup_remset_size() {
 873   // Setup sparse and fine-grain tables sizes.
 874   // table_size = base * (log(region_size / 1M) + 1)
 875   const int LOG_M = 20;
 876   int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0);
 877   if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) {
 878     G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1);
 879   }
 880   if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) {
 881     G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1);
 882   }
 883   guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity");
 884 }
 885 
 886 bool HeapRegionRemSet::claim_iter() {
 887   if (_iter_state != Unclaimed) return false;
 888   jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed);
 889   return (res == Unclaimed);
 890 }
 891 
 892 void HeapRegionRemSet::set_iter_complete() {
 893   _iter_state = Complete;
 894 }
 895 
 896 bool HeapRegionRemSet::iter_is_complete() {
 897   return _iter_state == Complete;
 898 }
 899 
 900 #ifndef PRODUCT
 901 void HeapRegionRemSet::print() {
 902   HeapRegionRemSetIterator iter(this);
 903   size_t card_index;
 904   while (iter.has_next(card_index)) {
 905     HeapWord* card_start =
 906       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
 907     gclog_or_tty->print_cr("  Card " PTR_FORMAT, card_start);
 908   }
 909   if (iter.n_yielded() != occupied()) {
 910     gclog_or_tty->print_cr("Yielded disagrees with occupied:");
 911     gclog_or_tty->print_cr("  %6d yielded (%6d coarse, %6d fine).",
 912                   iter.n_yielded(),
 913                   iter.n_yielded_coarse(), iter.n_yielded_fine());
 914     gclog_or_tty->print_cr("  %6d occ     (%6d coarse, %6d fine).",
 915                   occupied(), occ_coarse(), occ_fine());
 916   }
 917   guarantee(iter.n_yielded() == occupied(),
 918             "We should have yielded all the represented cards.");
 919 }
 920 #endif
 921 
 922 void HeapRegionRemSet::cleanup() {
 923   SparsePRT::cleanup_all();
 924 }
 925 
 926 void HeapRegionRemSet::clear() {
 927   MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
 928   clear_locked();
 929 }
 930 
 931 void HeapRegionRemSet::clear_locked() {
 932   _code_roots.clear();
 933   _other_regions.clear();
 934   assert(occupied_locked() == 0, "Should be clear.");
 935   reset_for_par_iteration();
 936 }
 937 
 938 void HeapRegionRemSet::reset_for_par_iteration() {
 939   _iter_state = Unclaimed;
 940   _iter_claimed = 0;
 941   // It's good to check this to make sure that the two methods are in sync.
 942   assert(verify_ready_for_par_iteration(), "post-condition");
 943 }
 944 
 945 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs,
 946                              BitMap* region_bm, BitMap* card_bm) {
 947   _other_regions.scrub(ctbs, region_bm, card_bm);
 948 }
 949 
 950 // Code roots support
 951 //
 952 // The code root set is protected by two separate locking schemes
 953 // When at safepoint the per-hrrs lock must be held during modifications
 954 // except when doing a full gc.
 955 // When not at safepoint the CodeCache_lock must be held during modifications.
 956 // When concurrent readers access the contains() function
 957 // (during the evacuation phase) no removals are allowed.
 958 
 959 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) {
 960   assert(nm != NULL, "sanity");
 961   assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()),
 962           err_msg("should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s",
 963           BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())));
 964   // Optimistic unlocked contains-check
 965   if (!_code_roots.contains(nm)) {
 966     MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag);
 967     add_strong_code_root_locked(nm);
 968   }
 969 }
 970 
 971 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) {
 972   assert(nm != NULL, "sanity");
 973   assert((CodeCache_lock->owned_by_self() ||
 974          (SafepointSynchronize::is_at_safepoint() &&
 975           (_m.owned_by_self() || Thread::current()->is_VM_thread()))),
 976           err_msg("not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s",
 977           BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()),
 978           BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())));
 979   _code_roots.add(nm);
 980 }
 981 
 982 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) {
 983   assert(nm != NULL, "sanity");
 984   assert_locked_or_safepoint(CodeCache_lock);
 985 
 986   MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag);
 987   _code_roots.remove(nm);
 988 
 989   // Check that there were no duplicates
 990   guarantee(!_code_roots.contains(nm), "duplicate entry found");
 991 }
 992 
 993 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const {
 994   _code_roots.nmethods_do(blk);
 995 }
 996 
 997 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) {
 998   _code_roots.clean(hr);
 999 }
1000 
1001 size_t HeapRegionRemSet::strong_code_roots_mem_size() {
1002   return _code_roots.mem_size();
1003 }
1004 
1005 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) :
1006   _hrrs(hrrs),
1007   _g1h(G1CollectedHeap::heap()),
1008   _coarse_map(&hrrs->_other_regions._coarse_map),
1009   _bosa(hrrs->bosa()),
1010   _is(Sparse),
1011   // Set these values so that we increment to the first region.
1012   _coarse_cur_region_index(-1),
1013   _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1),
1014   _cur_card_in_prt(HeapRegion::CardsPerRegion),
1015   _fine_cur_prt(NULL),
1016   _n_yielded_coarse(0),
1017   _n_yielded_fine(0),
1018   _n_yielded_sparse(0),
1019   _sparse_iter(&hrrs->_other_regions._sparse_table) {}
1020 
1021 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) {
1022   if (_hrrs->_other_regions._n_coarse_entries == 0) return false;
1023   // Go to the next card.
1024   _coarse_cur_region_cur_card++;
1025   // Was the last the last card in the current region?
1026   if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) {
1027     // Yes: find the next region.  This may leave _coarse_cur_region_index
1028     // Set to the last index, in which case there are no more coarse
1029     // regions.
1030     _coarse_cur_region_index =
1031       (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1);
1032     if ((size_t)_coarse_cur_region_index < _coarse_map->size()) {
1033       _coarse_cur_region_cur_card = 0;
1034       HeapWord* r_bot =
1035         _g1h->region_at((uint) _coarse_cur_region_index)->bottom();
1036       _cur_region_card_offset = _bosa->index_for(r_bot);
1037     } else {
1038       return false;
1039     }
1040   }
1041   // If we didn't return false above, then we can yield a card.
1042   card_index = _cur_region_card_offset + _coarse_cur_region_cur_card;
1043   return true;
1044 }
1045 
1046 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) {
1047   if (fine_has_next()) {
1048     _cur_card_in_prt =
1049       _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1050   }
1051   if (_cur_card_in_prt == HeapRegion::CardsPerRegion) {
1052     // _fine_cur_prt may still be NULL in case if there are not PRTs at all for
1053     // the remembered set.
1054     if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) {
1055       return false;
1056     }
1057     PerRegionTable* next_prt = _fine_cur_prt->next();
1058     switch_to_prt(next_prt);
1059     _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1);
1060   }
1061 
1062   card_index = _cur_region_card_offset + _cur_card_in_prt;
1063   guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion,
1064             err_msg("Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt));
1065   return true;
1066 }
1067 
1068 bool HeapRegionRemSetIterator::fine_has_next() {
1069   return _cur_card_in_prt != HeapRegion::CardsPerRegion;
1070 }
1071 
1072 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) {
1073   assert(prt != NULL, "Cannot switch to NULL prt");
1074   _fine_cur_prt = prt;
1075 
1076   HeapWord* r_bot = _fine_cur_prt->hr()->bottom();
1077   _cur_region_card_offset = _bosa->index_for(r_bot);
1078 
1079   // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1.
1080   // To avoid special-casing this start case, and not miss the first bitmap
1081   // entry, initialize _cur_region_cur_card with -1 instead of 0.
1082   _cur_card_in_prt = (size_t)-1;
1083 }
1084 
1085 bool HeapRegionRemSetIterator::has_next(size_t& card_index) {
1086   switch (_is) {
1087   case Sparse: {
1088     if (_sparse_iter.has_next(card_index)) {
1089       _n_yielded_sparse++;
1090       return true;
1091     }
1092     // Otherwise, deliberate fall-through
1093     _is = Fine;
1094     PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts;
1095     if (initial_fine_prt != NULL) {
1096       switch_to_prt(_hrrs->_other_regions._first_all_fine_prts);
1097     }
1098   }
1099   case Fine:
1100     if (fine_has_next(card_index)) {
1101       _n_yielded_fine++;
1102       return true;
1103     }
1104     // Otherwise, deliberate fall-through
1105     _is = Coarse;
1106   case Coarse:
1107     if (coarse_has_next(card_index)) {
1108       _n_yielded_coarse++;
1109       return true;
1110     }
1111     // Otherwise...
1112     break;
1113   }
1114   assert(ParallelGCThreads > 1 ||
1115          n_yielded() == _hrrs->occupied(),
1116          "Should have yielded all the cards in the rem set "
1117          "(in the non-par case).");
1118   return false;
1119 }
1120 
1121 
1122 
1123 OopOrNarrowOopStar* HeapRegionRemSet::_recorded_oops = NULL;
1124 HeapWord**          HeapRegionRemSet::_recorded_cards = NULL;
1125 HeapRegion**        HeapRegionRemSet::_recorded_regions = NULL;
1126 int                 HeapRegionRemSet::_n_recorded = 0;
1127 
1128 HeapRegionRemSet::Event* HeapRegionRemSet::_recorded_events = NULL;
1129 int*         HeapRegionRemSet::_recorded_event_index = NULL;
1130 int          HeapRegionRemSet::_n_recorded_events = 0;
1131 
1132 void HeapRegionRemSet::record(HeapRegion* hr, OopOrNarrowOopStar f) {
1133   if (_recorded_oops == NULL) {
1134     assert(_n_recorded == 0
1135            && _recorded_cards == NULL
1136            && _recorded_regions == NULL,
1137            "Inv");
1138     _recorded_oops    = NEW_C_HEAP_ARRAY(OopOrNarrowOopStar, MaxRecorded, mtGC);
1139     _recorded_cards   = NEW_C_HEAP_ARRAY(HeapWord*,          MaxRecorded, mtGC);
1140     _recorded_regions = NEW_C_HEAP_ARRAY(HeapRegion*,        MaxRecorded, mtGC);
1141   }
1142   if (_n_recorded == MaxRecorded) {
1143     gclog_or_tty->print_cr("Filled up 'recorded' (%d).", MaxRecorded);
1144   } else {
1145     _recorded_cards[_n_recorded] =
1146       (HeapWord*)align_size_down(uintptr_t(f),
1147                                  CardTableModRefBS::card_size);
1148     _recorded_oops[_n_recorded] = f;
1149     _recorded_regions[_n_recorded] = hr;
1150     _n_recorded++;
1151   }
1152 }
1153 
1154 void HeapRegionRemSet::record_event(Event evnt) {
1155   if (!G1RecordHRRSEvents) return;
1156 
1157   if (_recorded_events == NULL) {
1158     assert(_n_recorded_events == 0
1159            && _recorded_event_index == NULL,
1160            "Inv");
1161     _recorded_events = NEW_C_HEAP_ARRAY(Event, MaxRecordedEvents, mtGC);
1162     _recorded_event_index = NEW_C_HEAP_ARRAY(int, MaxRecordedEvents, mtGC);
1163   }
1164   if (_n_recorded_events == MaxRecordedEvents) {
1165     gclog_or_tty->print_cr("Filled up 'recorded_events' (%d).", MaxRecordedEvents);
1166   } else {
1167     _recorded_events[_n_recorded_events] = evnt;
1168     _recorded_event_index[_n_recorded_events] = _n_recorded;
1169     _n_recorded_events++;
1170   }
1171 }
1172 
1173 void HeapRegionRemSet::print_event(outputStream* str, Event evnt) {
1174   switch (evnt) {
1175   case Event_EvacStart:
1176     str->print("Evac Start");
1177     break;
1178   case Event_EvacEnd:
1179     str->print("Evac End");
1180     break;
1181   case Event_RSUpdateEnd:
1182     str->print("RS Update End");
1183     break;
1184   }
1185 }
1186 
1187 void HeapRegionRemSet::print_recorded() {
1188   int cur_evnt = 0;
1189   Event cur_evnt_kind = Event_illegal;
1190   int cur_evnt_ind = 0;
1191   if (_n_recorded_events > 0) {
1192     cur_evnt_kind = _recorded_events[cur_evnt];
1193     cur_evnt_ind = _recorded_event_index[cur_evnt];
1194   }
1195 
1196   for (int i = 0; i < _n_recorded; i++) {
1197     while (cur_evnt < _n_recorded_events && i == cur_evnt_ind) {
1198       gclog_or_tty->print("Event: ");
1199       print_event(gclog_or_tty, cur_evnt_kind);
1200       gclog_or_tty->cr();
1201       cur_evnt++;
1202       if (cur_evnt < MaxRecordedEvents) {
1203         cur_evnt_kind = _recorded_events[cur_evnt];
1204         cur_evnt_ind = _recorded_event_index[cur_evnt];
1205       }
1206     }
1207     gclog_or_tty->print("Added card " PTR_FORMAT " to region [" PTR_FORMAT "...]"
1208                         " for ref " PTR_FORMAT ".\n",
1209                         _recorded_cards[i], _recorded_regions[i]->bottom(),
1210                         _recorded_oops[i]);
1211   }
1212 }
1213 
1214 void HeapRegionRemSet::reset_for_cleanup_tasks() {
1215   SparsePRT::reset_for_cleanup_tasks();
1216 }
1217 
1218 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) {
1219   _other_regions.do_cleanup_work(hrrs_cleanup_task);
1220 }
1221 
1222 void
1223 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) {
1224   SparsePRT::finish_cleanup_task(hrrs_cleanup_task);
1225 }
1226 
1227 #ifndef PRODUCT
1228 void PerRegionTable::test_fl_mem_size() {
1229   PerRegionTable* dummy = alloc(NULL);
1230 
1231   size_t min_prt_size = sizeof(void*) + dummy->bm()->size_in_words() * HeapWordSize;
1232   assert(dummy->mem_size() > min_prt_size,
1233          err_msg("PerRegionTable memory usage is suspiciously small, only has " SIZE_FORMAT " bytes. "
1234                  "Should be at least " SIZE_FORMAT " bytes.", dummy->mem_size(), min_prt_size));
1235   free(dummy);
1236   guarantee(dummy->mem_size() == fl_mem_size(), "fl_mem_size() does not return the correct element size");
1237   // try to reset the state
1238   _free_list = NULL;
1239   delete dummy;
1240 }
1241 
1242 void HeapRegionRemSet::test_prt() {
1243   PerRegionTable::test_fl_mem_size();
1244 }
1245 
1246 void HeapRegionRemSet::test() {
1247   os::sleep(Thread::current(), (jlong)5000, false);
1248   G1CollectedHeap* g1h = G1CollectedHeap::heap();
1249 
1250   // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same
1251   // hash bucket.
1252   HeapRegion* hr0 = g1h->region_at(0);
1253   HeapRegion* hr1 = g1h->region_at(1);
1254   HeapRegion* hr2 = g1h->region_at(5);
1255   HeapRegion* hr3 = g1h->region_at(6);
1256   HeapRegion* hr4 = g1h->region_at(7);
1257   HeapRegion* hr5 = g1h->region_at(8);
1258 
1259   HeapWord* hr1_start = hr1->bottom();
1260   HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2;
1261   HeapWord* hr1_last = hr1->end() - 1;
1262 
1263   HeapWord* hr2_start = hr2->bottom();
1264   HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2;
1265   HeapWord* hr2_last = hr2->end() - 1;
1266 
1267   HeapWord* hr3_start = hr3->bottom();
1268   HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2;
1269   HeapWord* hr3_last = hr3->end() - 1;
1270 
1271   HeapRegionRemSet* hrrs = hr0->rem_set();
1272 
1273   // Make three references from region 0x101...
1274   hrrs->add_reference((OopOrNarrowOopStar)hr1_start);
1275   hrrs->add_reference((OopOrNarrowOopStar)hr1_mid);
1276   hrrs->add_reference((OopOrNarrowOopStar)hr1_last);
1277 
1278   hrrs->add_reference((OopOrNarrowOopStar)hr2_start);
1279   hrrs->add_reference((OopOrNarrowOopStar)hr2_mid);
1280   hrrs->add_reference((OopOrNarrowOopStar)hr2_last);
1281 
1282   hrrs->add_reference((OopOrNarrowOopStar)hr3_start);
1283   hrrs->add_reference((OopOrNarrowOopStar)hr3_mid);
1284   hrrs->add_reference((OopOrNarrowOopStar)hr3_last);
1285 
1286   // Now cause a coarsening.
1287   hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom());
1288   hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom());
1289 
1290   // Now, does iteration yield these three?
1291   HeapRegionRemSetIterator iter(hrrs);
1292   size_t sum = 0;
1293   size_t card_index;
1294   while (iter.has_next(card_index)) {
1295     HeapWord* card_start =
1296       G1CollectedHeap::heap()->bot_shared()->address_for_index(card_index);
1297     gclog_or_tty->print_cr("  Card " PTR_FORMAT ".", card_start);
1298     sum++;
1299   }
1300   guarantee(sum == 11 - 3 + 2048, "Failure");
1301   guarantee(sum == hrrs->occupied(), "Failure");
1302 }
1303 #endif