rev 7084 : [mq]: demacro

   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.
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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).
  14  *
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  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
  27 
  28 #include "gc_implementation/g1/g1BlockOffsetTable.hpp"
  29 #include "gc_implementation/g1/g1_specialized_oop_closures.hpp"
  30 #include "gc_implementation/g1/heapRegionType.hpp"
  31 #include "gc_implementation/g1/survRateGroup.hpp"
  32 #include "gc_implementation/shared/ageTable.hpp"
  33 #include "gc_implementation/shared/spaceDecorator.hpp"
  34 #include "memory/space.inline.hpp"
  35 #include "memory/watermark.hpp"
  36 #include "utilities/macros.hpp"
  37 
  38 // A HeapRegion is the smallest piece of a G1CollectedHeap that
  39 // can be collected independently.
  40 
  41 // NOTE: Although a HeapRegion is a Space, its
  42 // Space::initDirtyCardClosure method must not be called.
  43 // The problem is that the existence of this method breaks
  44 // the independence of barrier sets from remembered sets.
  45 // The solution is to remove this method from the definition
  46 // of a Space.
  47 
  48 class HeapRegionRemSet;
  49 class HeapRegionRemSetIterator;
  50 class HeapRegion;
  51 class HeapRegionSetBase;
  52 class nmethod;
  53 
  54 #define HR_FORMAT "%u:(%s)["PTR_FORMAT","PTR_FORMAT","PTR_FORMAT"]"
  55 #define HR_FORMAT_PARAMS(_hr_) \
  56                 (_hr_)->hrm_index(), \
  57                 (_hr_)->get_short_type_str(), \
  58                 p2i((_hr_)->bottom()), p2i((_hr_)->top()), p2i((_hr_)->end())
  59 
  60 // sentinel value for hrm_index
  61 #define G1_NO_HRM_INDEX ((uint) -1)
  62 
  63 // A dirty card to oop closure for heap regions. It
  64 // knows how to get the G1 heap and how to use the bitmap
  65 // in the concurrent marker used by G1 to filter remembered
  66 // sets.
  67 
  68 class HeapRegionDCTOC : public DirtyCardToOopClosure {
  69 public:
  70   // Specification of possible DirtyCardToOopClosure filtering.
  71   enum FilterKind {
  72     NoFilterKind,
  73     IntoCSFilterKind,
  74     OutOfRegionFilterKind
  75   };
  76 
  77 protected:
  78   HeapRegion* _hr;
  79   FilterKind _fk;
  80   G1CollectedHeap* _g1;
  81 
  82   // Walk the given memory region from bottom to (actual) top
  83   // looking for objects and applying the oop closure (_cl) to
  84   // them. The base implementation of this treats the area as
  85   // blocks, where a block may or may not be an object. Sub-
  86   // classes should override this to provide more accurate
  87   // or possibly more efficient walking.
  88   void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
  89 
  90 public:
  91   HeapRegionDCTOC(G1CollectedHeap* g1,
  92                   HeapRegion* hr, ExtendedOopClosure* cl,
  93                   CardTableModRefBS::PrecisionStyle precision,
  94                   FilterKind fk);
  95 };
  96 
  97 // The complicating factor is that BlockOffsetTable diverged
  98 // significantly, and we need functionality that is only in the G1 version.
  99 // So I copied that code, which led to an alternate G1 version of
 100 // OffsetTableContigSpace.  If the two versions of BlockOffsetTable could
 101 // be reconciled, then G1OffsetTableContigSpace could go away.
 102 
 103 // The idea behind time stamps is the following. Doing a save_marks on
 104 // all regions at every GC pause is time consuming (if I remember
 105 // well, 10ms or so). So, we would like to do that only for regions
 106 // that are GC alloc regions. To achieve this, we use time
 107 // stamps. For every evacuation pause, G1CollectedHeap generates a
 108 // unique time stamp (essentially a counter that gets
 109 // incremented). Every time we want to call save_marks on a region,
 110 // we set the saved_mark_word to top and also copy the current GC
 111 // time stamp to the time stamp field of the space. Reading the
 112 // saved_mark_word involves checking the time stamp of the
 113 // region. If it is the same as the current GC time stamp, then we
 114 // can safely read the saved_mark_word field, as it is valid. If the
 115 // time stamp of the region is not the same as the current GC time
 116 // stamp, then we instead read top, as the saved_mark_word field is
 117 // invalid. Time stamps (on the regions and also on the
 118 // G1CollectedHeap) are reset at every cleanup (we iterate over
 119 // the regions anyway) and at the end of a Full GC. The current scheme
 120 // that uses sequential unsigned ints will fail only if we have 4b
 121 // evacuation pauses between two cleanups, which is _highly_ unlikely.
 122 class G1OffsetTableContigSpace: public CompactibleSpace {
 123   friend class VMStructs;
 124   HeapWord* _top;
 125  protected:
 126   G1BlockOffsetArrayContigSpace _offsets;
 127   Mutex _par_alloc_lock;
 128   volatile unsigned _gc_time_stamp;
 129   // When we need to retire an allocation region, while other threads
 130   // are also concurrently trying to allocate into it, we typically
 131   // allocate a dummy object at the end of the region to ensure that
 132   // no more allocations can take place in it. However, sometimes we
 133   // want to know where the end of the last "real" object we allocated
 134   // into the region was and this is what this keeps track.
 135   HeapWord* _pre_dummy_top;
 136 
 137  public:
 138   G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
 139                            MemRegion mr);
 140 
 141   void set_top(HeapWord* value) { _top = value; }
 142   HeapWord* top() const { return _top; }
 143 
 144  protected:
 145   // Reset the G1OffsetTableContigSpace.
 146   virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
 147 
 148   HeapWord** top_addr() { return &_top; }
 149   // Allocation helpers (return NULL if full).
 150   inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
 151   inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
 152 
 153  public:
 154   void reset_after_compaction() { set_top(compaction_top()); }
 155 
 156   size_t used() const { return byte_size(bottom(), top()); }
 157   size_t free() const { return byte_size(top(), end()); }
 158   bool is_free_block(const HeapWord* p) const { return p >= top(); }
 159 
 160   MemRegion used_region() const { return MemRegion(bottom(), top()); }
 161 
 162   void object_iterate(ObjectClosure* blk);
 163   void safe_object_iterate(ObjectClosure* blk);
 164 
 165   void set_bottom(HeapWord* value);
 166   void set_end(HeapWord* value);
 167 
 168   virtual HeapWord* saved_mark_word() const;
 169   void record_top_and_timestamp();
 170   void reset_gc_time_stamp() { _gc_time_stamp = 0; }
 171   unsigned get_gc_time_stamp() { return _gc_time_stamp; }
 172 
 173   // See the comment above in the declaration of _pre_dummy_top for an
 174   // explanation of what it is.
 175   void set_pre_dummy_top(HeapWord* pre_dummy_top) {
 176     assert(is_in(pre_dummy_top) && pre_dummy_top <= top(), "pre-condition");
 177     _pre_dummy_top = pre_dummy_top;
 178   }
 179   HeapWord* pre_dummy_top() {
 180     return (_pre_dummy_top == NULL) ? top() : _pre_dummy_top;
 181   }
 182   void reset_pre_dummy_top() { _pre_dummy_top = NULL; }
 183 
 184   virtual void clear(bool mangle_space);
 185 
 186   HeapWord* block_start(const void* p);
 187   HeapWord* block_start_const(const void* p) const;
 188 


 189   // Add offset table update.
 190   virtual HeapWord* allocate(size_t word_size);
 191   HeapWord* par_allocate(size_t word_size);
 192 
 193   // MarkSweep support phase3
 194   virtual HeapWord* initialize_threshold();
 195   virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
 196 
 197   virtual void print() const;
 198 
 199   void reset_bot() {
 200     _offsets.reset_bot();
 201   }
 202 
 203   void print_bot_on(outputStream* out) {
 204     _offsets.print_on(out);
 205   }
 206 };
 207 
 208 class HeapRegion: public G1OffsetTableContigSpace {
 209   friend class VMStructs;
 210  private:
 211 
 212   // The remembered set for this region.
 213   // (Might want to make this "inline" later, to avoid some alloc failure
 214   // issues.)
 215   HeapRegionRemSet* _rem_set;
 216 
 217   G1BlockOffsetArrayContigSpace* offsets() { return &_offsets; }
 218 
 219  protected:
 220   // The index of this region in the heap region sequence.
 221   uint  _hrm_index;
 222 
 223   HeapRegionType _type;
 224 
 225   // For a humongous region, region in which it starts.
 226   HeapRegion* _humongous_start_region;
 227   // True iff the region is in current collection_set.
 228   bool _in_collection_set;
 229 
 230   // True iff an attempt to evacuate an object in the region failed.
 231   bool _evacuation_failed;
 232 
 233   // A heap region may be a member one of a number of special subsets, each
 234   // represented as linked lists through the field below.  Currently, there
 235   // is only one set:
 236   //   The collection set.
 237   HeapRegion* _next_in_special_set;
 238 
 239   // next region in the young "generation" region set
 240   HeapRegion* _next_young_region;
 241 
 242   // Next region whose cards need cleaning
 243   HeapRegion* _next_dirty_cards_region;
 244 
 245   // Fields used by the HeapRegionSetBase class and subclasses.
 246   HeapRegion* _next;
 247   HeapRegion* _prev;
 248 #ifdef ASSERT
 249   HeapRegionSetBase* _containing_set;
 250 #endif // ASSERT
 251 
 252   // For parallel heapRegion traversal.
 253   jint _claimed;
 254 
 255   // We use concurrent marking to determine the amount of live data
 256   // in each heap region.
 257   size_t _prev_marked_bytes;    // Bytes known to be live via last completed marking.
 258   size_t _next_marked_bytes;    // Bytes known to be live via in-progress marking.
 259 
 260   // The calculated GC efficiency of the region.
 261   double _gc_efficiency;
 262 
 263   int  _young_index_in_cset;
 264   SurvRateGroup* _surv_rate_group;
 265   int  _age_index;
 266 
 267   // The start of the unmarked area. The unmarked area extends from this
 268   // word until the top and/or end of the region, and is the part
 269   // of the region for which no marking was done, i.e. objects may
 270   // have been allocated in this part since the last mark phase.
 271   // "prev" is the top at the start of the last completed marking.
 272   // "next" is the top at the start of the in-progress marking (if any.)
 273   HeapWord* _prev_top_at_mark_start;
 274   HeapWord* _next_top_at_mark_start;
 275   // If a collection pause is in progress, this is the top at the start
 276   // of that pause.
 277 
 278   void init_top_at_mark_start() {
 279     assert(_prev_marked_bytes == 0 &&
 280            _next_marked_bytes == 0,
 281            "Must be called after zero_marked_bytes.");
 282     HeapWord* bot = bottom();
 283     _prev_top_at_mark_start = bot;
 284     _next_top_at_mark_start = bot;
 285   }
 286 
 287   // Cached attributes used in the collection set policy information
 288 
 289   // The RSet length that was added to the total value
 290   // for the collection set.
 291   size_t _recorded_rs_length;
 292 
 293   // The predicted elapsed time that was added to total value
 294   // for the collection set.
 295   double _predicted_elapsed_time_ms;
 296 
 297   // The predicted number of bytes to copy that was added to
 298   // the total value for the collection set.
 299   size_t _predicted_bytes_to_copy;
 300 
 301  public:
 302   HeapRegion(uint hrm_index,
 303              G1BlockOffsetSharedArray* sharedOffsetArray,
 304              MemRegion mr);
 305 
 306   // Initializing the HeapRegion not only resets the data structure, but also
 307   // resets the BOT for that heap region.
 308   // The default values for clear_space means that we will do the clearing if
 309   // there's clearing to be done ourselves. We also always mangle the space.
 310   virtual void initialize(MemRegion mr, bool clear_space = false, bool mangle_space = SpaceDecorator::Mangle);
 311 
 312   static int    LogOfHRGrainBytes;
 313   static int    LogOfHRGrainWords;
 314 
 315   static size_t GrainBytes;
 316   static size_t GrainWords;
 317   static size_t CardsPerRegion;
 318 
 319   static size_t align_up_to_region_byte_size(size_t sz) {
 320     return (sz + (size_t) GrainBytes - 1) &
 321                                       ~((1 << (size_t) LogOfHRGrainBytes) - 1);
 322   }
 323 
 324   static size_t max_region_size();
 325 
 326   // It sets up the heap region size (GrainBytes / GrainWords), as
 327   // well as other related fields that are based on the heap region
 328   // size (LogOfHRGrainBytes / LogOfHRGrainWords /
 329   // CardsPerRegion). All those fields are considered constant
 330   // throughout the JVM's execution, therefore they should only be set
 331   // up once during initialization time.
 332   static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
 333 
 334   enum ClaimValues {
 335     InitialClaimValue          = 0,
 336     FinalCountClaimValue       = 1,
 337     NoteEndClaimValue          = 2,
 338     ScrubRemSetClaimValue      = 3,
 339     ParVerifyClaimValue        = 4,
 340     RebuildRSClaimValue        = 5,
 341     ParEvacFailureClaimValue   = 6,
 342     AggregateCountClaimValue   = 7,
 343     VerifyCountClaimValue      = 8,
 344     ParMarkRootClaimValue      = 9
 345   };
 346 
 347   // All allocated blocks are occupied by objects in a HeapRegion
 348   bool block_is_obj(const HeapWord* p) const;
 349 
 350   // Returns the object size for all valid block starts
 351   // and the amount of unallocated words if called on top()
 352   size_t block_size(const HeapWord* p) const;
 353 
 354   // Functions for scan_and_forward support.
 355   void prepare_for_compaction(CompactPoint* cp);
 356 
 357   inline HeapWord* scan_limit() const {
 358     return top();
 359   }
 360 
 361   inline bool scanned_block_is_obj(const HeapWord* addr) const {
 362     return true; // Always true, since scan_limit is top
 363   }
 364 
 365   inline size_t scanned_block_size(const HeapWord* addr) const {
 366     return HeapRegion::block_size(addr); // Avoid virtual call
 367   }
 368 
 369   inline HeapWord* par_allocate_no_bot_updates(size_t word_size);
 370   inline HeapWord* allocate_no_bot_updates(size_t word_size);
 371 
 372   // If this region is a member of a HeapRegionManager, the index in that
 373   // sequence, otherwise -1.
 374   uint hrm_index() const { return _hrm_index; }
 375 
 376   // The number of bytes marked live in the region in the last marking phase.
 377   size_t marked_bytes()    { return _prev_marked_bytes; }
 378   size_t live_bytes() {
 379     return (top() - prev_top_at_mark_start()) * HeapWordSize + marked_bytes();
 380   }
 381 
 382   // The number of bytes counted in the next marking.
 383   size_t next_marked_bytes() { return _next_marked_bytes; }
 384   // The number of bytes live wrt the next marking.
 385   size_t next_live_bytes() {
 386     return
 387       (top() - next_top_at_mark_start()) * HeapWordSize + next_marked_bytes();
 388   }
 389 
 390   // A lower bound on the amount of garbage bytes in the region.
 391   size_t garbage_bytes() {
 392     size_t used_at_mark_start_bytes =
 393       (prev_top_at_mark_start() - bottom()) * HeapWordSize;
 394     assert(used_at_mark_start_bytes >= marked_bytes(),
 395            "Can't mark more than we have.");
 396     return used_at_mark_start_bytes - marked_bytes();
 397   }
 398 
 399   // Return the amount of bytes we'll reclaim if we collect this
 400   // region. This includes not only the known garbage bytes in the
 401   // region but also any unallocated space in it, i.e., [top, end),
 402   // since it will also be reclaimed if we collect the region.
 403   size_t reclaimable_bytes() {
 404     size_t known_live_bytes = live_bytes();
 405     assert(known_live_bytes <= capacity(), "sanity");
 406     return capacity() - known_live_bytes;
 407   }
 408 
 409   // An upper bound on the number of live bytes in the region.
 410   size_t max_live_bytes() { return used() - garbage_bytes(); }
 411 
 412   void add_to_marked_bytes(size_t incr_bytes) {
 413     _next_marked_bytes = _next_marked_bytes + incr_bytes;
 414     assert(_next_marked_bytes <= used(), "invariant" );
 415   }
 416 
 417   void zero_marked_bytes()      {
 418     _prev_marked_bytes = _next_marked_bytes = 0;
 419   }
 420 
 421   const char* get_type_str() const { return _type.get_str(); }
 422   const char* get_short_type_str() const { return _type.get_short_str(); }
 423 
 424   bool is_free() const { return _type.is_free(); }
 425 
 426   bool is_young()    const { return _type.is_young();    }
 427   bool is_eden()     const { return _type.is_eden();     }
 428   bool is_survivor() const { return _type.is_survivor(); }
 429 
 430   bool isHumongous() const { return _type.is_humongous(); }
 431   bool startsHumongous() const { return _type.is_starts_humongous(); }
 432   bool continuesHumongous() const { return _type.is_continues_humongous();   }
 433 
 434   bool is_old() const { return _type.is_old(); }
 435 
 436   // For a humongous region, region in which it starts.
 437   HeapRegion* humongous_start_region() const {
 438     return _humongous_start_region;
 439   }
 440 
 441   // Return the number of distinct regions that are covered by this region:
 442   // 1 if the region is not humongous, >= 1 if the region is humongous.
 443   uint region_num() const {
 444     if (!isHumongous()) {
 445       return 1U;
 446     } else {
 447       assert(startsHumongous(), "doesn't make sense on HC regions");
 448       assert(capacity() % HeapRegion::GrainBytes == 0, "sanity");
 449       return (uint) (capacity() >> HeapRegion::LogOfHRGrainBytes);
 450     }
 451   }
 452 
 453   // Return the index + 1 of the last HC regions that's associated
 454   // with this HS region.
 455   uint last_hc_index() const {
 456     assert(startsHumongous(), "don't call this otherwise");
 457     return hrm_index() + region_num();
 458   }
 459 
 460   // Same as Space::is_in_reserved, but will use the original size of the region.
 461   // The original size is different only for start humongous regions. They get
 462   // their _end set up to be the end of the last continues region of the
 463   // corresponding humongous object.
 464   bool is_in_reserved_raw(const void* p) const {
 465     return _bottom <= p && p < orig_end();
 466   }
 467 
 468   // Makes the current region be a "starts humongous" region, i.e.,
 469   // the first region in a series of one or more contiguous regions
 470   // that will contain a single "humongous" object. The two parameters
 471   // are as follows:
 472   //
 473   // new_top : The new value of the top field of this region which
 474   // points to the end of the humongous object that's being
 475   // allocated. If there is more than one region in the series, top
 476   // will lie beyond this region's original end field and on the last
 477   // region in the series.
 478   //
 479   // new_end : The new value of the end field of this region which
 480   // points to the end of the last region in the series. If there is
 481   // one region in the series (namely: this one) end will be the same
 482   // as the original end of this region.
 483   //
 484   // Updating top and end as described above makes this region look as
 485   // if it spans the entire space taken up by all the regions in the
 486   // series and an single allocation moved its top to new_top. This
 487   // ensures that the space (capacity / allocated) taken up by all
 488   // humongous regions can be calculated by just looking at the
 489   // "starts humongous" regions and by ignoring the "continues
 490   // humongous" regions.
 491   void set_startsHumongous(HeapWord* new_top, HeapWord* new_end);
 492 
 493   // Makes the current region be a "continues humongous'
 494   // region. first_hr is the "start humongous" region of the series
 495   // which this region will be part of.
 496   void set_continuesHumongous(HeapRegion* first_hr);
 497 
 498   // Unsets the humongous-related fields on the region.
 499   void clear_humongous();
 500 
 501   // If the region has a remembered set, return a pointer to it.
 502   HeapRegionRemSet* rem_set() const {
 503     return _rem_set;
 504   }
 505 
 506   // True iff the region is in current collection_set.
 507   bool in_collection_set() const {
 508     return _in_collection_set;
 509   }
 510   void set_in_collection_set(bool b) {
 511     _in_collection_set = b;
 512   }
 513   HeapRegion* next_in_collection_set() {
 514     assert(in_collection_set(), "should only invoke on member of CS.");
 515     assert(_next_in_special_set == NULL ||
 516            _next_in_special_set->in_collection_set(),
 517            "Malformed CS.");
 518     return _next_in_special_set;
 519   }
 520   void set_next_in_collection_set(HeapRegion* r) {
 521     assert(in_collection_set(), "should only invoke on member of CS.");
 522     assert(r == NULL || r->in_collection_set(), "Malformed CS.");
 523     _next_in_special_set = r;
 524   }
 525 
 526   // Methods used by the HeapRegionSetBase class and subclasses.
 527 
 528   // Getter and setter for the next and prev fields used to link regions into
 529   // linked lists.
 530   HeapRegion* next()              { return _next; }
 531   HeapRegion* prev()              { return _prev; }
 532 
 533   void set_next(HeapRegion* next) { _next = next; }
 534   void set_prev(HeapRegion* prev) { _prev = prev; }
 535 
 536   // Every region added to a set is tagged with a reference to that
 537   // set. This is used for doing consistency checking to make sure that
 538   // the contents of a set are as they should be and it's only
 539   // available in non-product builds.
 540 #ifdef ASSERT
 541   void set_containing_set(HeapRegionSetBase* containing_set) {
 542     assert((containing_set == NULL && _containing_set != NULL) ||
 543            (containing_set != NULL && _containing_set == NULL),
 544            err_msg("containing_set: "PTR_FORMAT" "
 545                    "_containing_set: "PTR_FORMAT,
 546                    p2i(containing_set), p2i(_containing_set)));
 547 
 548     _containing_set = containing_set;
 549   }
 550 
 551   HeapRegionSetBase* containing_set() { return _containing_set; }
 552 #else // ASSERT
 553   void set_containing_set(HeapRegionSetBase* containing_set) { }
 554 
 555   // containing_set() is only used in asserts so there's no reason
 556   // to provide a dummy version of it.
 557 #endif // ASSERT
 558 
 559   HeapRegion* get_next_young_region() { return _next_young_region; }
 560   void set_next_young_region(HeapRegion* hr) {
 561     _next_young_region = hr;
 562   }
 563 
 564   HeapRegion* get_next_dirty_cards_region() const { return _next_dirty_cards_region; }
 565   HeapRegion** next_dirty_cards_region_addr() { return &_next_dirty_cards_region; }
 566   void set_next_dirty_cards_region(HeapRegion* hr) { _next_dirty_cards_region = hr; }
 567   bool is_on_dirty_cards_region_list() const { return get_next_dirty_cards_region() != NULL; }
 568 
 569   // For the start region of a humongous sequence, it's original end().
 570   HeapWord* orig_end() const { return _bottom + GrainWords; }
 571 
 572   // Reset HR stuff to default values.
 573   void hr_clear(bool par, bool clear_space, bool locked = false);
 574   void par_clear();
 575 
 576   // Get the start of the unmarked area in this region.
 577   HeapWord* prev_top_at_mark_start() const { return _prev_top_at_mark_start; }
 578   HeapWord* next_top_at_mark_start() const { return _next_top_at_mark_start; }
 579 
 580   // Note the start or end of marking. This tells the heap region
 581   // that the collector is about to start or has finished (concurrently)
 582   // marking the heap.
 583 
 584   // Notify the region that concurrent marking is starting. Initialize
 585   // all fields related to the next marking info.
 586   inline void note_start_of_marking();
 587 
 588   // Notify the region that concurrent marking has finished. Copy the
 589   // (now finalized) next marking info fields into the prev marking
 590   // info fields.
 591   inline void note_end_of_marking();
 592 
 593   // Notify the region that it will be used as to-space during a GC
 594   // and we are about to start copying objects into it.
 595   inline void note_start_of_copying(bool during_initial_mark);
 596 
 597   // Notify the region that it ceases being to-space during a GC and
 598   // we will not copy objects into it any more.
 599   inline void note_end_of_copying(bool during_initial_mark);
 600 
 601   // Notify the region that we are about to start processing
 602   // self-forwarded objects during evac failure handling.
 603   void note_self_forwarding_removal_start(bool during_initial_mark,
 604                                           bool during_conc_mark);
 605 
 606   // Notify the region that we have finished processing self-forwarded
 607   // objects during evac failure handling.
 608   void note_self_forwarding_removal_end(bool during_initial_mark,
 609                                         bool during_conc_mark,
 610                                         size_t marked_bytes);
 611 
 612   // Returns "false" iff no object in the region was allocated when the
 613   // last mark phase ended.
 614   bool is_marked() { return _prev_top_at_mark_start != bottom(); }
 615 
 616   void reset_during_compaction() {
 617     assert(isHumongous() && startsHumongous(),
 618            "should only be called for starts humongous regions");
 619 
 620     zero_marked_bytes();
 621     init_top_at_mark_start();
 622   }
 623 
 624   void calc_gc_efficiency(void);
 625   double gc_efficiency() { return _gc_efficiency;}
 626 
 627   int  young_index_in_cset() const { return _young_index_in_cset; }
 628   void set_young_index_in_cset(int index) {
 629     assert( (index == -1) || is_young(), "pre-condition" );
 630     _young_index_in_cset = index;
 631   }
 632 
 633   int age_in_surv_rate_group() {
 634     assert( _surv_rate_group != NULL, "pre-condition" );
 635     assert( _age_index > -1, "pre-condition" );
 636     return _surv_rate_group->age_in_group(_age_index);
 637   }
 638 
 639   void record_surv_words_in_group(size_t words_survived) {
 640     assert( _surv_rate_group != NULL, "pre-condition" );
 641     assert( _age_index > -1, "pre-condition" );
 642     int age_in_group = age_in_surv_rate_group();
 643     _surv_rate_group->record_surviving_words(age_in_group, words_survived);
 644   }
 645 
 646   int age_in_surv_rate_group_cond() {
 647     if (_surv_rate_group != NULL)
 648       return age_in_surv_rate_group();
 649     else
 650       return -1;
 651   }
 652 
 653   SurvRateGroup* surv_rate_group() {
 654     return _surv_rate_group;
 655   }
 656 
 657   void install_surv_rate_group(SurvRateGroup* surv_rate_group) {
 658     assert( surv_rate_group != NULL, "pre-condition" );
 659     assert( _surv_rate_group == NULL, "pre-condition" );
 660     assert( is_young(), "pre-condition" );
 661 
 662     _surv_rate_group = surv_rate_group;
 663     _age_index = surv_rate_group->next_age_index();
 664   }
 665 
 666   void uninstall_surv_rate_group() {
 667     if (_surv_rate_group != NULL) {
 668       assert( _age_index > -1, "pre-condition" );
 669       assert( is_young(), "pre-condition" );
 670 
 671       _surv_rate_group = NULL;
 672       _age_index = -1;
 673     } else {
 674       assert( _age_index == -1, "pre-condition" );
 675     }
 676   }
 677 
 678   void set_free() { _type.set_free(); }
 679 
 680   void set_eden()        { _type.set_eden();        }
 681   void set_eden_pre_gc() { _type.set_eden_pre_gc(); }
 682   void set_survivor()    { _type.set_survivor();    }
 683 
 684   void set_old() { _type.set_old(); }
 685 
 686   // Determine if an object has been allocated since the last
 687   // mark performed by the collector. This returns true iff the object
 688   // is within the unmarked area of the region.
 689   bool obj_allocated_since_prev_marking(oop obj) const {
 690     return (HeapWord *) obj >= prev_top_at_mark_start();
 691   }
 692   bool obj_allocated_since_next_marking(oop obj) const {
 693     return (HeapWord *) obj >= next_top_at_mark_start();
 694   }
 695 
 696   // For parallel heapRegion traversal.
 697   bool claimHeapRegion(int claimValue);
 698   jint claim_value() { return _claimed; }
 699   // Use this carefully: only when you're sure no one is claiming...
 700   void set_claim_value(int claimValue) { _claimed = claimValue; }
 701 
 702   // Returns the "evacuation_failed" property of the region.
 703   bool evacuation_failed() { return _evacuation_failed; }
 704 
 705   // Sets the "evacuation_failed" property of the region.
 706   void set_evacuation_failed(bool b) {
 707     _evacuation_failed = b;
 708 
 709     if (b) {
 710       _next_marked_bytes = 0;
 711     }
 712   }
 713 
 714   // Requires that "mr" be entirely within the region.
 715   // Apply "cl->do_object" to all objects that intersect with "mr".
 716   // If the iteration encounters an unparseable portion of the region,
 717   // or if "cl->abort()" is true after a closure application,
 718   // terminate the iteration and return the address of the start of the
 719   // subregion that isn't done.  (The two can be distinguished by querying
 720   // "cl->abort()".)  Return of "NULL" indicates that the iteration
 721   // completed.
 722   HeapWord*
 723   object_iterate_mem_careful(MemRegion mr, ObjectClosure* cl);
 724 
 725   // filter_young: if true and the region is a young region then we
 726   // skip the iteration.
 727   // card_ptr: if not NULL, and we decide that the card is not young
 728   // and we iterate over it, we'll clean the card before we start the
 729   // iteration.
 730   HeapWord*
 731   oops_on_card_seq_iterate_careful(MemRegion mr,
 732                                    FilterOutOfRegionClosure* cl,
 733                                    bool filter_young,
 734                                    jbyte* card_ptr);
 735 
 736   size_t recorded_rs_length() const        { return _recorded_rs_length; }
 737   double predicted_elapsed_time_ms() const { return _predicted_elapsed_time_ms; }
 738   size_t predicted_bytes_to_copy() const   { return _predicted_bytes_to_copy; }
 739 
 740   void set_recorded_rs_length(size_t rs_length) {
 741     _recorded_rs_length = rs_length;
 742   }
 743 
 744   void set_predicted_elapsed_time_ms(double ms) {
 745     _predicted_elapsed_time_ms = ms;
 746   }
 747 
 748   void set_predicted_bytes_to_copy(size_t bytes) {
 749     _predicted_bytes_to_copy = bytes;
 750   }
 751 
 752   virtual CompactibleSpace* next_compaction_space() const;
 753 
 754   virtual void reset_after_compaction();
 755 
 756   // Routines for managing a list of code roots (attached to the
 757   // this region's RSet) that point into this heap region.
 758   void add_strong_code_root(nmethod* nm);
 759   void add_strong_code_root_locked(nmethod* nm);
 760   void remove_strong_code_root(nmethod* nm);
 761 
 762   // Applies blk->do_code_blob() to each of the entries in
 763   // the strong code roots list for this region
 764   void strong_code_roots_do(CodeBlobClosure* blk) const;
 765 
 766   // Verify that the entries on the strong code root list for this
 767   // region are live and include at least one pointer into this region.
 768   void verify_strong_code_roots(VerifyOption vo, bool* failures) const;
 769 
 770   void print() const;
 771   void print_on(outputStream* st) const;
 772 
 773   // vo == UsePrevMarking  -> use "prev" marking information,
 774   // vo == UseNextMarking -> use "next" marking information
 775   // vo == UseMarkWord    -> use the mark word in the object header
 776   //
 777   // NOTE: Only the "prev" marking information is guaranteed to be
 778   // consistent most of the time, so most calls to this should use
 779   // vo == UsePrevMarking.
 780   // Currently, there is only one case where this is called with
 781   // vo == UseNextMarking, which is to verify the "next" marking
 782   // information at the end of remark.
 783   // Currently there is only one place where this is called with
 784   // vo == UseMarkWord, which is to verify the marking during a
 785   // full GC.
 786   void verify(VerifyOption vo, bool *failures) const;
 787 
 788   // Override; it uses the "prev" marking information
 789   virtual void verify() const;
 790 };
 791 
 792 // HeapRegionClosure is used for iterating over regions.
 793 // Terminates the iteration when the "doHeapRegion" method returns "true".
 794 class HeapRegionClosure : public StackObj {
 795   friend class HeapRegionManager;
 796   friend class G1CollectedHeap;
 797 
 798   bool _complete;
 799   void incomplete() { _complete = false; }
 800 
 801  public:
 802   HeapRegionClosure(): _complete(true) {}
 803 
 804   // Typically called on each region until it returns true.
 805   virtual bool doHeapRegion(HeapRegion* r) = 0;
 806 
 807   // True after iteration if the closure was applied to all heap regions
 808   // and returned "false" in all cases.
 809   bool complete() { return _complete; }
 810 };
 811 
 812 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_HPP
--- EOF ---