1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
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  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).
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  24 
  25 #ifndef SHARE_GC_G1_HEAPREGION_HPP
  26 #define SHARE_GC_G1_HEAPREGION_HPP
  27 
  28 #include "gc/g1/g1BlockOffsetTable.hpp"
  29 #include "gc/g1/g1HeapRegionTraceType.hpp"
  30 #include "gc/g1/heapRegionTracer.hpp"
  31 #include "gc/g1/heapRegionType.hpp"
  32 #include "gc/g1/survRateGroup.hpp"
  33 #include "gc/shared/ageTable.hpp"
  34 #include "gc/shared/cardTable.hpp"
  35 #include "gc/shared/verifyOption.hpp"
  36 #include "gc/shared/spaceDecorator.hpp"
  37 #include "utilities/macros.hpp"
  38 
  39 // A HeapRegion is the smallest piece of a G1CollectedHeap that
  40 // can be collected independently.
  41 
  42 // NOTE: Although a HeapRegion is a Space, its
  43 // Space::initDirtyCardClosure method must not be called.
  44 // The problem is that the existence of this method breaks
  45 // the independence of barrier sets from remembered sets.
  46 // The solution is to remove this method from the definition
  47 // of a Space.
  48 
  49 // Each heap region is self contained. top() and end() can never
  50 // be set beyond the end of the region. For humongous objects,
  51 // the first region is a StartsHumongous region. If the humongous
  52 // object is larger than a heap region, the following regions will
  53 // be of type ContinuesHumongous. In this case the top() of the
  54 // StartHumongous region and all ContinuesHumongous regions except
  55 // the last will point to their own end. The last ContinuesHumongous
  56 // region may have top() equal the end of object if there isn't
  57 // room for filler objects to pad out to the end of the region.
  58 
  59 class G1CollectedHeap;
  60 class G1CMBitMap;
  61 class G1IsAliveAndApplyClosure;
  62 class HeapRegionRemSet;
  63 class HeapRegionRemSetIterator;
  64 class HeapRegion;
  65 class HeapRegionSetBase;
  66 class nmethod;
  67 
  68 #define HR_FORMAT "%u:(%s)[" PTR_FORMAT "," PTR_FORMAT "," PTR_FORMAT "]"
  69 #define HR_FORMAT_PARAMS(_hr_) \
  70                 (_hr_)->hrm_index(), \
  71                 (_hr_)->get_short_type_str(), \
  72                 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
  73 
  74 // sentinel value for hrm_index
  75 #define G1_NO_HRM_INDEX ((uint) -1)
  76 
  77 // The complicating factor is that BlockOffsetTable diverged
  78 // significantly, and we need functionality that is only in the G1 version.
  79 // So I copied that code, which led to an alternate G1 version of
  80 // OffsetTableContigSpace.  If the two versions of BlockOffsetTable could
  81 // be reconciled, then G1OffsetTableContigSpace could go away.
  82 
  83 // The idea behind time stamps is the following. We want to keep track of
  84 // the highest address where it's safe to scan objects for each region.
  85 // This is only relevant for current GC alloc regions so we keep a time stamp
  86 // per region to determine if the region has been allocated during the current
  87 // GC or not. If the time stamp is current we report a scan_top value which
  88 // was saved at the end of the previous GC for retained alloc regions and which is
  89 // equal to the bottom for all other regions.
  90 // There is a race between card scanners and allocating gc workers where we must ensure
  91 // that card scanners do not read the memory allocated by the gc workers.
  92 // In order to enforce that, we must not return a value of _top which is more recent than the
  93 // time stamp. This is due to the fact that a region may become a gc alloc region at
  94 // some point after we've read the timestamp value as being < the current time stamp.
  95 // The time stamps are re-initialized to zero at cleanup and at Full GCs.
  96 // The current scheme that uses sequential unsigned ints will fail only if we have 4b
  97 // evacuation pauses between two cleanups, which is _highly_ unlikely.
  98 class G1ContiguousSpace: public CompactibleSpace {
  99   friend class VMStructs;
 100   HeapWord* volatile _top;
 101  protected:
 102   G1BlockOffsetTablePart _bot_part;
 103   Mutex _par_alloc_lock;
 104   // When we need to retire an allocation region, while other threads
 105   // are also concurrently trying to allocate into it, we typically
 106   // allocate a dummy object at the end of the region to ensure that
 107   // no more allocations can take place in it. However, sometimes we
 108   // want to know where the end of the last "real" object we allocated
 109   // into the region was and this is what this keeps track.
 110   HeapWord* _pre_dummy_top;
 111 
 112  public:
 113   G1ContiguousSpace(G1BlockOffsetTable* bot);
 114 
 115   void set_top(HeapWord* value) { _top = value; }
 116   HeapWord* top() const { return _top; }
 117 
 118  protected:
 119   // Reset the G1ContiguousSpace.
 120   virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
 121 
 122   HeapWord* volatile* top_addr() { return &_top; }
 123   // Try to allocate at least min_word_size and up to desired_size from this Space.
 124   // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
 125   // space allocated.
 126   // This version assumes that all allocation requests to this Space are properly
 127   // synchronized.
 128   inline HeapWord* allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
 129   // Try to allocate at least min_word_size and up to desired_size from this Space.
 130   // Returns NULL if not possible, otherwise sets actual_word_size to the amount of
 131   // space allocated.
 132   // This version synchronizes with other calls to par_allocate_impl().
 133   inline HeapWord* par_allocate_impl(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
 134 
 135  public:
 136   void reset_after_compaction() { set_top(compaction_top()); }
 137 
 138   size_t used() const { return byte_size(bottom(), top()); }
 139   size_t free() const { return byte_size(top(), end()); }
 140   bool is_free_block(const HeapWord* p) const { return p >= top(); }
 141 
 142   MemRegion used_region() const { return MemRegion(bottom(), top()); }
 143 
 144   void object_iterate(ObjectClosure* blk);
 145   void safe_object_iterate(ObjectClosure* blk);
 146 
 147   void mangle_unused_area() PRODUCT_RETURN;
 148   void mangle_unused_area_complete() PRODUCT_RETURN;
 149 
 150   // See the comment above in the declaration of _pre_dummy_top for an
 151   // explanation of what it is.
 152   void set_pre_dummy_top(HeapWord* pre_dummy_top) {
 153     assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
 154     _pre_dummy_top = pre_dummy_top;
 155   }
 156   HeapWord* pre_dummy_top() {
 157     return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
 158   }
 159   void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
 160 
 161   virtual void clear(bool mangle_space);
 162 
 163   HeapWord* block_start(const void* p);
 164   HeapWord* block_start_const(const void* p) const;
 165 
 166   // Allocation (return NULL if full).  Assumes the caller has established
 167   // mutually exclusive access to the space.
 168   HeapWord* allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
 169   // Allocation (return NULL if full).  Enforces mutual exclusion internally.
 170   HeapWord* par_allocate(size_t min_word_size, size_t desired_word_size, size_t* actual_word_size);
 171 
 172   virtual HeapWord* allocate(size_t word_size);
 173   virtual HeapWord* par_allocate(size_t word_size);
 174 
 175   HeapWord* saved_mark_word() const { ShouldNotReachHere(); return NULL; }
 176 
 177   // MarkSweep support phase3
 178   virtual HeapWord* initialize_threshold();
 179   virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
 180 
 181   virtual void print() const;
 182 
 183   void reset_bot() {
 184     _bot_part.reset_bot();
 185   }
 186 
 187   void print_bot_on(outputStream* out) {
 188     _bot_part.print_on(out);
 189   }
 190 };
 191 
 192 class HeapRegion: public G1ContiguousSpace {
 193   friend class VMStructs;
 194   // Allow scan_and_forward to call (private) overrides for auxiliary functions on this class
 195   template <typename SpaceType>
 196   friend void CompactibleSpace::scan_and_forward(SpaceType* space, CompactPoint* cp);
 197  private:
 198 
 199   // The remembered set for this region.
 200   // (Might want to make this "inline" later, to avoid some alloc failure
 201   // issues.)
 202   HeapRegionRemSet* _rem_set;
 203 
 204   // Auxiliary functions for scan_and_forward support.
 205   // See comments for CompactibleSpace for more information.
 206   inline HeapWord* scan_limit() const {
 207     return top();
 208   }
 209 
 210   inline bool scanned_block_is_obj(const HeapWord* addr) const {
 211     return true; // Always true, since scan_limit is top
 212   }
 213 
 214   inline size_t scanned_block_size(const HeapWord* addr) const {
 215     return HeapRegion::block_size(addr); // Avoid virtual call
 216   }
 217 
 218   void report_region_type_change(G1HeapRegionTraceType::Type to);
 219 
 220   // Returns whether the given object address refers to a dead object, and either the
 221   // size of the object (if live) or the size of the block (if dead) in size.
 222   // May
 223   // - only called with obj < top()
 224   // - not called on humongous objects or archive regions
 225   inline bool is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const;
 226 
 227  protected:
 228   // The index of this region in the heap region sequence.
 229   uint  _hrm_index;
 230 
 231   HeapRegionType _type;
 232 
 233   // For a humongous region, region in which it starts.
 234   HeapRegion* _humongous_start_region;
 235 
 236   // True iff an attempt to evacuate an object in the region failed.
 237   bool _evacuation_failed;
 238 
 239   // Fields used by the HeapRegionSetBase class and subclasses.
 240   HeapRegion* _next;
 241   HeapRegion* _prev;
 242 #ifdef ASSERT
 243   HeapRegionSetBase* _containing_set;
 244 #endif // ASSERT
 245 
 246   // We use concurrent marking to determine the amount of live data
 247   // in each heap region.
 248   size_t _prev_marked_bytes;    // Bytes known to be live via last completed marking.
 249   size_t _next_marked_bytes;    // Bytes known to be live via in-progress marking.
 250 
 251   // The calculated GC efficiency of the region.
 252   double _gc_efficiency;
 253 
 254   static const uint InvalidCSetIndex = UINT_MAX;
 255 
 256   // The index in the optional regions array, if this region
 257   // is considered optional during a mixed collections.
 258   uint _index_in_opt_cset;
 259   int  _young_index_in_cset;
 260   SurvRateGroup* _surv_rate_group;
 261   int  _age_index;
 262 
 263   // The start of the unmarked area. The unmarked area extends from this
 264   // word until the top and/or end of the region, and is the part
 265   // of the region for which no marking was done, i.e. objects may
 266   // have been allocated in this part since the last mark phase.
 267   // "prev" is the top at the start of the last completed marking.
 268   // "next" is the top at the start of the in-progress marking (if any.)
 269   HeapWord* _prev_top_at_mark_start;
 270   HeapWord* _next_top_at_mark_start;
 271   // If a collection pause is in progress, this is the top at the start
 272   // of that pause.
 273 
 274   void init_top_at_mark_start() {
 275     assert(_prev_marked_bytes == 0 &&
 276            _next_marked_bytes == 0,
 277            "Must be called after zero_marked_bytes.");
 278     HeapWord* bot = bottom();
 279     _prev_top_at_mark_start = bot;
 280     _next_top_at_mark_start = bot;
 281   }
 282 
 283   // Cached attributes used in the collection set policy information
 284 
 285   // The RSet length that was added to the total value
 286   // for the collection set.
 287   size_t _recorded_rs_length;
 288 
 289   // The predicted elapsed time that was added to total value
 290   // for the collection set.
 291   double _predicted_elapsed_time_ms;
 292 
 293   // Iterate over the references in a humongous objects and apply the given closure
 294   // to them.
 295   // Humongous objects are allocated directly in the old-gen. So we need special
 296   // handling for concurrent processing encountering an in-progress allocation.
 297   template <class Closure, bool is_gc_active>
 298   inline bool do_oops_on_card_in_humongous(MemRegion mr,
 299                                            Closure* cl,
 300                                            G1CollectedHeap* g1h);
 301 
 302   // Returns the block size of the given (dead, potentially having its class unloaded) object
 303   // starting at p extending to at most the prev TAMS using the given mark bitmap.
 304   inline size_t block_size_using_bitmap(const HeapWord* p, const G1CMBitMap* const prev_bitmap) const;
 305  public:
 306   HeapRegion(uint hrm_index,
 307              G1BlockOffsetTable* bot,
 308              MemRegion mr);
 309 
 310   // Initializing the HeapRegion not only resets the data structure, but also
 311   // resets the BOT for that heap region.
 312   // The default values for clear_space means that we will do the clearing if
 313   // there's clearing to be done ourselves. We also always mangle the space.
 314   virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
 315 
 316   static int    LogOfHRGrainBytes;
 317   static int    LogOfHRGrainWords;
 318 
 319   static size_t GrainBytes;
 320   static size_t GrainWords;
 321   static size_t CardsPerRegion;
 322 
 323   static size_t align_up_to_region_byte_size(size_t sz) {
 324     return (sz + (size_t) GrainBytes - 1) &
 325                                       ~((1 << (size_t) LogOfHRGrainBytes) - 1);
 326   }
 327 
 328 
 329   // Returns whether a field is in the same region as the obj it points to.
 330   template <typename T>
 331   static bool is_in_same_region(T* p, oop obj) {
 332     assert(p != NULL, "p can't be NULL");
 333     assert(obj != NULL, "obj can't be NULL");
 334     return (((uintptr_t) p ^ cast_from_oop<uintptr_t>(obj)) >> LogOfHRGrainBytes) == 0;
 335   }
 336 
 337   static size_t max_region_size();
 338   static size_t min_region_size_in_words();
 339 
 340   // It sets up the heap region size (GrainBytes / GrainWords), as
 341   // well as other related fields that are based on the heap region
 342   // size (LogOfHRGrainBytes / LogOfHRGrainWords /
 343   // CardsPerRegion). All those fields are considered constant
 344   // throughout the JVM's execution, therefore they should only be set
 345   // up once during initialization time.
 346   static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
 347 
 348   // All allocated blocks are occupied by objects in a HeapRegion
 349   bool block_is_obj(const HeapWord* p) const;
 350 
 351   // Returns whether the given object is dead based on TAMS and bitmap.
 352   bool is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const;
 353 
 354   // Returns the object size for all valid block starts
 355   // and the amount of unallocated words if called on top()
 356   size_t block_size(const HeapWord* p) const;
 357 
 358   // Scans through the region using the bitmap to determine what
 359   // objects to call size_t ApplyToMarkedClosure::apply(oop) for.
 360   template<typename ApplyToMarkedClosure>
 361   inline void apply_to_marked_objects(G1CMBitMap* bitmap, ApplyToMarkedClosure* closure);
 362   // Override for scan_and_forward support.
 363   void prepare_for_compaction(CompactPoint* cp);
 364   // Update heap region to be consistent after compaction.
 365   void complete_compaction();
 366 
 367   inline HeapWord* par_allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* word_size);
 368   inline HeapWord* allocate_no_bot_updates(size_t word_size);
 369   inline HeapWord* allocate_no_bot_updates(size_t min_word_size, size_t desired_word_size, size_t* actual_size);
 370 
 371   // If this region is a member of a HeapRegionManager, the index in that
 372   // sequence, otherwise -1.
 373   uint hrm_index() const { return _hrm_index; }
 374 
 375   // The number of bytes marked live in the region in the last marking phase.
 376   size_t marked_bytes()    { return _prev_marked_bytes; }
 377   size_t live_bytes() {
 378     return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
 379   }
 380 
 381   // The number of bytes counted in the next marking.
 382   size_t next_marked_bytes() { return _next_marked_bytes; }
 383   // The number of bytes live wrt the next marking.
 384   size_t next_live_bytes() {
 385     return
 386       (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
 387   }
 388 
 389   // A lower bound on the amount of garbage bytes in the region.
 390   size_t garbage_bytes() {
 391     size_t used_at_mark_start_bytes =
 392       (prev_top_at_mark_start() - bottom()) * HeapWordSize;
 393     return used_at_mark_start_bytes - marked_bytes();
 394   }
 395 
 396   // Return the amount of bytes we'll reclaim if we collect this
 397   // region. This includes not only the known garbage bytes in the
 398   // region but also any unallocated space in it, i.e., [top, end),
 399   // since it will also be reclaimed if we collect the region.
 400   size_t reclaimable_bytes() {
 401     size_t known_live_bytes = live_bytes();
 402     assert(known_live_bytes <= capacity(), "sanity");
 403     return capacity() - known_live_bytes;
 404   }
 405 
 406   // An upper bound on the number of live bytes in the region.
 407   size_t max_live_bytes() { return used() - garbage_bytes(); }
 408 
 409   void add_to_marked_bytes(size_t incr_bytes) {
 410     _next_marked_bytes = _next_marked_bytes + incr_bytes;
 411   }
 412 
 413   void zero_marked_bytes()      {
 414     _prev_marked_bytes = _next_marked_bytes = 0;
 415   }
 416 
 417   const char* get_type_str() const { return _type.get_str(); }
 418   const char* get_short_type_str() const { return _type.get_short_str(); }
 419   G1HeapRegionTraceType::Type get_trace_type() { return _type.get_trace_type(); }
 420 
 421   bool is_free() const { return _type.is_free(); }
 422 
 423   bool is_young()    const { return _type.is_young();    }
 424   bool is_eden()     const { return _type.is_eden();     }
 425   bool is_survivor() const { return _type.is_survivor(); }
 426 
 427   bool is_humongous() const { return _type.is_humongous(); }
 428   bool is_starts_humongous() const { return _type.is_starts_humongous(); }
 429   bool is_continues_humongous() const { return _type.is_continues_humongous();   }
 430 
 431   bool is_old() const { return _type.is_old(); }
 432 
 433   bool is_old_or_humongous() const { return _type.is_old_or_humongous(); }
 434 
 435   bool is_old_or_humongous_or_archive() const { return _type.is_old_or_humongous_or_archive(); }
 436 
 437   // A pinned region contains objects which are not moved by garbage collections.
 438   // Humongous regions and archive regions are pinned.
 439   bool is_pinned() const { return _type.is_pinned(); }
 440 
 441   // An archive region is a pinned region, also tagged as old, which
 442   // should not be marked during mark/sweep. This allows the address
 443   // space to be shared by JVM instances.
 444   bool is_archive()        const { return _type.is_archive(); }
 445   bool is_open_archive()   const { return _type.is_open_archive(); }
 446   bool is_closed_archive() const { return _type.is_closed_archive(); }
 447 
 448   // For a humongous region, region in which it starts.
 449   HeapRegion* humongous_start_region() const {
 450     return _humongous_start_region;
 451   }
 452 
 453   // Makes the current region be a "starts humongous" region, i.e.,
 454   // the first region in a series of one or more contiguous regions
 455   // that will contain a single "humongous" object.
 456   //
 457   // obj_top : points to the top of the humongous object.
 458   // fill_size : size of the filler object at the end of the region series.
 459   void set_starts_humongous(HeapWord* obj_top, size_t fill_size);
 460 
 461   // Makes the current region be a "continues humongous'
 462   // region. first_hr is the "start humongous" region of the series
 463   // which this region will be part of.
 464   void set_continues_humongous(HeapRegion* first_hr);
 465 
 466   // Unsets the humongous-related fields on the region.
 467   void clear_humongous();
 468 
 469   // If the region has a remembered set, return a pointer to it.
 470   HeapRegionRemSet* rem_set() const {
 471     return _rem_set;
 472   }
 473 
 474   inline bool in_collection_set() const;
 475 
 476   // Methods used by the HeapRegionSetBase class and subclasses.
 477 
 478   // Getter and setter for the next and prev fields used to link regions into
 479   // linked lists.
 480   HeapRegion* next()              { return _next; }
 481   HeapRegion* prev()              { return _prev; }
 482 
 483   void set_next(HeapRegion* next) { _next = next; }
 484   void set_prev(HeapRegion* prev) { _prev = prev; }
 485 
 486   // Every region added to a set is tagged with a reference to that
 487   // set. This is used for doing consistency checking to make sure that
 488   // the contents of a set are as they should be and it's only
 489   // available in non-product builds.
 490 #ifdef ASSERT
 491   void set_containing_set(HeapRegionSetBase* containing_set) {
 492     assert((containing_set == NULL && _containing_set != NULL) ||
 493            (containing_set != NULL && _containing_set == NULL),
 494            "containing_set: " PTR_FORMAT " "
 495            "_containing_set: " PTR_FORMAT,
 496            p2i(containing_set), p2i(_containing_set));
 497 
 498     _containing_set = containing_set;
 499   }
 500 
 501   HeapRegionSetBase* containing_set() { return _containing_set; }
 502 #else // ASSERT
 503   void set_containing_set(HeapRegionSetBase* containing_set) { }
 504 
 505   // containing_set() is only used in asserts so there's no reason
 506   // to provide a dummy version of it.
 507 #endif // ASSERT
 508 
 509 
 510   // Reset the HeapRegion to default values.
 511   // If skip_remset is true, do not clear the remembered set.
 512   // If clear_space is true, clear the HeapRegion's memory.
 513   // If locked is true, assume we are the only thread doing this operation.
 514   void hr_clear(bool skip_remset, bool clear_space, bool locked = false);
 515   // Clear the card table corresponding to this region.
 516   void clear_cardtable();
 517 
 518   // Get the start of the unmarked area in this region.
 519   HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
 520   HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
 521 
 522   // Note the start or end of marking. This tells the heap region
 523   // that the collector is about to start or has finished (concurrently)
 524   // marking the heap.
 525 
 526   // Notify the region that concurrent marking is starting. Initialize
 527   // all fields related to the next marking info.
 528   inline void note_start_of_marking();
 529 
 530   // Notify the region that concurrent marking has finished. Copy the
 531   // (now finalized) next marking info fields into the prev marking
 532   // info fields.
 533   inline void note_end_of_marking();
 534 
 535   // Notify the region that we are about to start processing
 536   // self-forwarded objects during evac failure handling.
 537   void note_self_forwarding_removal_start(bool during_initial_mark,
 538                                           bool during_conc_mark);
 539 
 540   // Notify the region that we have finished processing self-forwarded
 541   // objects during evac failure handling.
 542   void note_self_forwarding_removal_end(size_t marked_bytes);
 543 
 544   void reset_during_compaction() {
 545     assert(is_humongous(),
 546            "should only be called for humongous regions");
 547 
 548     zero_marked_bytes();
 549     init_top_at_mark_start();
 550   }
 551 
 552   void calc_gc_efficiency(void);
 553   double gc_efficiency() const { return _gc_efficiency;}
 554 
 555   uint index_in_opt_cset() const {
 556     assert(has_index_in_opt_cset(), "Opt cset index not set.");
 557     return _index_in_opt_cset;
 558   }
 559   bool has_index_in_opt_cset() const { return _index_in_opt_cset != InvalidCSetIndex; }
 560   void set_index_in_opt_cset(uint index) { _index_in_opt_cset = index; }
 561   void clear_index_in_opt_cset() { _index_in_opt_cset = InvalidCSetIndex; }
 562 
 563   int  young_index_in_cset() const { return _young_index_in_cset; }
 564   void set_young_index_in_cset(int index) {
 565     assert( (index == -1) || is_young(), "pre-condition" );
 566     _young_index_in_cset = index;
 567   }
 568 
 569   int age_in_surv_rate_group() {
 570     assert( _surv_rate_group != NULL, "pre-condition" );
 571     assert( _age_index > -1, "pre-condition" );
 572     return _surv_rate_group->age_in_group(_age_index);
 573   }
 574 
 575   void record_surv_words_in_group(size_t words_survived) {
 576     assert( _surv_rate_group != NULL, "pre-condition" );
 577     assert( _age_index > -1, "pre-condition" );
 578     int age_in_group = age_in_surv_rate_group();
 579     _surv_rate_group->record_surviving_words(age_in_group, words_survived);
 580   }
 581 
 582   int age_in_surv_rate_group_cond() {
 583     if (_surv_rate_group != NULL)
 584       return age_in_surv_rate_group();
 585     else
 586       return -1;
 587   }
 588 
 589   SurvRateGroup* surv_rate_group() {
 590     return _surv_rate_group;
 591   }
 592 
 593   void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
 594     assert( surv_rate_group != NULL, "pre-condition" );
 595     assert( _surv_rate_group == NULL, "pre-condition" );
 596     assert( is_young(), "pre-condition" );
 597 
 598     _surv_rate_group = surv_rate_group;
 599     _age_index = surv_rate_group->next_age_index();
 600   }
 601 
 602   void uninstall_surv_rate_group() {
 603     if (_surv_rate_group != NULL) {
 604       assert( _age_index > -1, "pre-condition" );
 605       assert( is_young(), "pre-condition" );
 606 
 607       _surv_rate_group = NULL;
 608       _age_index = -1;
 609     } else {
 610       assert( _age_index == -1, "pre-condition" );
 611     }
 612   }
 613 
 614   void set_free();
 615 
 616   void set_eden();
 617   void set_eden_pre_gc();
 618   void set_survivor();
 619 
 620   void move_to_old();
 621   void set_old();
 622 
 623   void set_open_archive();
 624   void set_closed_archive();
 625 
 626   // Determine if an object has been allocated since the last
 627   // mark performed by the collector. This returns true iff the object
 628   // is within the unmarked area of the region.
 629   bool obj_allocated_since_prev_marking(oop obj) const {
 630     return (HeapWord *) obj >= prev_top_at_mark_start();
 631   }
 632   bool obj_allocated_since_next_marking(oop obj) const {
 633     return (HeapWord *) obj >= next_top_at_mark_start();
 634   }
 635 
 636   // Returns the "evacuation_failed" property of the region.
 637   bool evacuation_failed() { return _evacuation_failed; }
 638 
 639   // Sets the "evacuation_failed" property of the region.
 640   void set_evacuation_failed(bool b) {
 641     _evacuation_failed = b;
 642 
 643     if (b) {
 644       _next_marked_bytes = 0;
 645     }
 646   }
 647 
 648   // Iterate over the objects overlapping part of a card, applying cl
 649   // to all references in the region.  This is a helper for
 650   // G1RemSet::refine_card*, and is tightly coupled with them.
 651   // mr is the memory region covered by the card, trimmed to the
 652   // allocated space for this region.  Must not be empty.
 653   // This region must be old or humongous.
 654   // Returns true if the designated objects were successfully
 655   // processed, false if an unparsable part of the heap was
 656   // encountered; that only happens when invoked concurrently with the
 657   // mutator.
 658   template <bool is_gc_active, class Closure>
 659   inline bool oops_on_card_seq_iterate_careful(MemRegion mr, Closure* cl);
 660 
 661   size_t recorded_rs_length() const        { return _recorded_rs_length; }
 662   double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
 663 
 664   void set_recorded_rs_length(size_t rs_length) {
 665     _recorded_rs_length = rs_length;
 666   }
 667 
 668   void set_predicted_elapsed_time_ms(double ms) {
 669     _predicted_elapsed_time_ms = ms;
 670   }
 671 
 672   // Routines for managing a list of code roots (attached to the
 673   // this region's RSet) that point into this heap region.
 674   void add_strong_code_root(nmethod* nm);
 675   void add_strong_code_root_locked(nmethod* nm);
 676   void remove_strong_code_root(nmethod* nm);
 677 
 678   // Applies blk->do_code_blob() to each of the entries in
 679   // the strong code roots list for this region
 680   void strong_code_roots_do(CodeBlobClosure* blk) const;
 681 
 682   // Verify that the entries on the strong code root list for this
 683   // region are live and include at least one pointer into this region.
 684   void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
 685 
 686   void print() const;
 687   void print_on(outputStream* st) const;
 688 
 689   // vo == UsePrevMarking -> use "prev" marking information,
 690   // vo == UseNextMarking -> use "next" marking information
 691   // vo == UseFullMarking -> use "next" marking bitmap but no TAMS
 692   //
 693   // NOTE: Only the "prev" marking information is guaranteed to be
 694   // consistent most of the time, so most calls to this should use
 695   // vo == UsePrevMarking.
 696   // Currently, there is only one case where this is called with
 697   // vo == UseNextMarking, which is to verify the "next" marking
 698   // information at the end of remark.
 699   // Currently there is only one place where this is called with
 700   // vo == UseFullMarking, which is to verify the marking during a
 701   // full GC.
 702   void verify(VerifyOption vo, bool *failures) const;
 703 
 704   // Override; it uses the "prev" marking information
 705   virtual void verify() const;
 706 
 707   void verify_rem_set(VerifyOption vo, bool *failures) const;
 708   void verify_rem_set() const;
 709 };
 710 
 711 // HeapRegionClosure is used for iterating over regions.
 712 // Terminates the iteration when the "do_heap_region" method returns "true".
 713 class HeapRegionClosure : public StackObj {
 714   friend class HeapRegionManager;
 715   friend class G1CollectionSet;
 716   friend class G1CollectionSetCandidates;
 717 
 718   bool _is_complete;
 719   void set_incomplete() { _is_complete = false; }
 720 
 721  public:
 722   HeapRegionClosure(): _is_complete(true) {}
 723 
 724   // Typically called on each region until it returns true.
 725   virtual bool do_heap_region(HeapRegion* r) = 0;
 726 
 727   // True after iteration if the closure was applied to all heap regions
 728   // and returned "false" in all cases.
 729   bool is_complete() { return _is_complete; }
 730 };
 731 
 732 #endif // SHARE_GC_G1_HEAPREGION_HPP