1 /*
   2  * Copyright (c) 2005, 2015, 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.
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  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP
  27 
  28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
  29 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
  30 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"
  31 #include "gc_implementation/parallelScavenge/psCompactionManager.hpp"
  32 #include "gc_implementation/shared/collectorCounters.hpp"
  33 #include "gc_implementation/shared/mutableSpace.hpp"
  34 #include "gc_interface/collectedHeap.hpp"
  35 #include "oops/oop.hpp"
  36 
  37 class ParallelScavengeHeap;
  38 class PSAdaptiveSizePolicy;
  39 class PSYoungGen;
  40 class PSOldGen;
  41 class ParCompactionManager;
  42 class ParallelTaskTerminator;
  43 class PSParallelCompact;
  44 class GCTaskManager;
  45 class GCTaskQueue;
  46 class PreGCValues;
  47 class MoveAndUpdateClosure;
  48 class RefProcTaskExecutor;
  49 class ParallelOldTracer;
  50 class STWGCTimer;
  51 
  52 // The SplitInfo class holds the information needed to 'split' a source region
  53 // so that the live data can be copied to two destination *spaces*.  Normally,
  54 // all the live data in a region is copied to a single destination space (e.g.,
  55 // everything live in a region in eden is copied entirely into the old gen).
  56 // However, when the heap is nearly full, all the live data in eden may not fit
  57 // into the old gen.  Copying only some of the regions from eden to old gen
  58 // requires finding a region that does not contain a partial object (i.e., no
  59 // live object crosses the region boundary) somewhere near the last object that
  60 // does fit into the old gen.  Since it's not always possible to find such a
  61 // region, splitting is necessary for predictable behavior.
  62 //
  63 // A region is always split at the end of the partial object.  This avoids
  64 // additional tests when calculating the new location of a pointer, which is a
  65 // very hot code path.  The partial object and everything to its left will be
  66 // copied to another space (call it dest_space_1).  The live data to the right
  67 // of the partial object will be copied either within the space itself, or to a
  68 // different destination space (distinct from dest_space_1).
  69 //
  70 // Split points are identified during the summary phase, when region
  71 // destinations are computed:  data about the split, including the
  72 // partial_object_size, is recorded in a SplitInfo record and the
  73 // partial_object_size field in the summary data is set to zero.  The zeroing is
  74 // possible (and necessary) since the partial object will move to a different
  75 // destination space than anything to its right, thus the partial object should
  76 // not affect the locations of any objects to its right.
  77 //
  78 // The recorded data is used during the compaction phase, but only rarely:  when
  79 // the partial object on the split region will be copied across a destination
  80 // region boundary.  This test is made once each time a region is filled, and is
  81 // a simple address comparison, so the overhead is negligible (see
  82 // PSParallelCompact::first_src_addr()).
  83 //
  84 // Notes:
  85 //
  86 // Only regions with partial objects are split; a region without a partial
  87 // object does not need any extra bookkeeping.
  88 //
  89 // At most one region is split per space, so the amount of data required is
  90 // constant.
  91 //
  92 // A region is split only when the destination space would overflow.  Once that
  93 // happens, the destination space is abandoned and no other data (even from
  94 // other source spaces) is targeted to that destination space.  Abandoning the
  95 // destination space may leave a somewhat large unused area at the end, if a
  96 // large object caused the overflow.
  97 //
  98 // Future work:
  99 //
 100 // More bookkeeping would be required to continue to use the destination space.
 101 // The most general solution would allow data from regions in two different
 102 // source spaces to be "joined" in a single destination region.  At the very
 103 // least, additional code would be required in next_src_region() to detect the
 104 // join and skip to an out-of-order source region.  If the join region was also
 105 // the last destination region to which a split region was copied (the most
 106 // likely case), then additional work would be needed to get fill_region() to
 107 // stop iteration and switch to a new source region at the right point.  Basic
 108 // idea would be to use a fake value for the top of the source space.  It is
 109 // doable, if a bit tricky.
 110 //
 111 // A simpler (but less general) solution would fill the remainder of the
 112 // destination region with a dummy object and continue filling the next
 113 // destination region.
 114 
 115 class SplitInfo
 116 {
 117 public:
 118   // Return true if this split info is valid (i.e., if a split has been
 119   // recorded).  The very first region cannot have a partial object and thus is
 120   // never split, so 0 is the 'invalid' value.
 121   bool is_valid() const { return _src_region_idx > 0; }
 122 
 123   // Return true if this split holds data for the specified source region.
 124   inline bool is_split(size_t source_region) const;
 125 
 126   // The index of the split region, the size of the partial object on that
 127   // region and the destination of the partial object.
 128   size_t    src_region_idx() const   { return _src_region_idx; }
 129   size_t    partial_obj_size() const { return _partial_obj_size; }
 130   HeapWord* destination() const      { return _destination; }
 131 
 132   // The destination count of the partial object referenced by this split
 133   // (either 1 or 2).  This must be added to the destination count of the
 134   // remainder of the source region.
 135   unsigned int destination_count() const { return _destination_count; }
 136 
 137   // If a word within the partial object will be written to the first word of a
 138   // destination region, this is the address of the destination region;
 139   // otherwise this is NULL.
 140   HeapWord* dest_region_addr() const     { return _dest_region_addr; }
 141 
 142   // If a word within the partial object will be written to the first word of a
 143   // destination region, this is the address of that word within the partial
 144   // object; otherwise this is NULL.
 145   HeapWord* first_src_addr() const       { return _first_src_addr; }
 146 
 147   // Record the data necessary to split the region src_region_idx.
 148   void record(size_t src_region_idx, size_t partial_obj_size,
 149               HeapWord* destination);
 150 
 151   void clear();
 152 
 153   DEBUG_ONLY(void verify_clear();)
 154 
 155 private:
 156   size_t       _src_region_idx;
 157   size_t       _partial_obj_size;
 158   HeapWord*    _destination;
 159   unsigned int _destination_count;
 160   HeapWord*    _dest_region_addr;
 161   HeapWord*    _first_src_addr;
 162 };
 163 
 164 inline bool SplitInfo::is_split(size_t region_idx) const
 165 {
 166   return _src_region_idx == region_idx && is_valid();
 167 }
 168 
 169 class SpaceInfo
 170 {
 171  public:
 172   MutableSpace* space() const { return _space; }
 173 
 174   // Where the free space will start after the collection.  Valid only after the
 175   // summary phase completes.
 176   HeapWord* new_top() const { return _new_top; }
 177 
 178   // Allows new_top to be set.
 179   HeapWord** new_top_addr() { return &_new_top; }
 180 
 181   // Where the smallest allowable dense prefix ends (used only for perm gen).
 182   HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
 183 
 184   // Where the dense prefix ends, or the compacted region begins.
 185   HeapWord* dense_prefix() const { return _dense_prefix; }
 186 
 187   // The start array for the (generation containing the) space, or NULL if there
 188   // is no start array.
 189   ObjectStartArray* start_array() const { return _start_array; }
 190 
 191   SplitInfo& split_info() { return _split_info; }
 192 
 193   void set_space(MutableSpace* s)           { _space = s; }
 194   void set_new_top(HeapWord* addr)          { _new_top = addr; }
 195   void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
 196   void set_dense_prefix(HeapWord* addr)     { _dense_prefix = addr; }
 197   void set_start_array(ObjectStartArray* s) { _start_array = s; }
 198 
 199   void publish_new_top() const              { _space->set_top(_new_top); }
 200 
 201  private:
 202   MutableSpace*     _space;
 203   HeapWord*         _new_top;
 204   HeapWord*         _min_dense_prefix;
 205   HeapWord*         _dense_prefix;
 206   ObjectStartArray* _start_array;
 207   SplitInfo         _split_info;
 208 };
 209 
 210 class ParallelCompactData
 211 {
 212 public:
 213   // Sizes are in HeapWords, unless indicated otherwise.
 214   static const size_t Log2RegionSize;
 215   static const size_t RegionSize;
 216   static const size_t RegionSizeBytes;
 217 
 218   // Mask for the bits in a size_t to get an offset within a region.
 219   static const size_t RegionSizeOffsetMask;
 220   // Mask for the bits in a pointer to get an offset within a region.
 221   static const size_t RegionAddrOffsetMask;
 222   // Mask for the bits in a pointer to get the address of the start of a region.
 223   static const size_t RegionAddrMask;
 224 
 225   static const size_t Log2BlockSize;
 226   static const size_t BlockSize;
 227   static const size_t BlockSizeBytes;
 228 
 229   static const size_t BlockSizeOffsetMask;
 230   static const size_t BlockAddrOffsetMask;
 231   static const size_t BlockAddrMask;
 232 
 233   static const size_t BlocksPerRegion;
 234   static const size_t Log2BlocksPerRegion;
 235 
 236   class RegionData
 237   {
 238   public:
 239     // Destination address of the region.
 240     HeapWord* destination() const { return _destination; }
 241 
 242     // The first region containing data destined for this region.
 243     size_t source_region() const { return _source_region; }
 244 
 245     // The object (if any) starting in this region and ending in a different
 246     // region that could not be updated during the main (parallel) compaction
 247     // phase.  This is different from _partial_obj_addr, which is an object that
 248     // extends onto a source region.  However, the two uses do not overlap in
 249     // time, so the same field is used to save space.
 250     HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
 251 
 252     // The starting address of the partial object extending onto the region.
 253     HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
 254 
 255     // Size of the partial object extending onto the region (words).
 256     size_t partial_obj_size() const { return _partial_obj_size; }
 257 
 258     // Size of live data that lies within this region due to objects that start
 259     // in this region (words).  This does not include the partial object
 260     // extending onto the region (if any), or the part of an object that extends
 261     // onto the next region (if any).
 262     size_t live_obj_size() const { return _dc_and_los & los_mask; }
 263 
 264     // Total live data that lies within the region (words).
 265     size_t data_size() const { return partial_obj_size() + live_obj_size(); }
 266 
 267     // The destination_count is the number of other regions to which data from
 268     // this region will be copied.  At the end of the summary phase, the valid
 269     // values of destination_count are
 270     //
 271     // 0 - data from the region will be compacted completely into itself, or the
 272     //     region is empty.  The region can be claimed and then filled.
 273     // 1 - data from the region will be compacted into 1 other region; some
 274     //     data from the region may also be compacted into the region itself.
 275     // 2 - data from the region will be copied to 2 other regions.
 276     //
 277     // During compaction as regions are emptied, the destination_count is
 278     // decremented (atomically) and when it reaches 0, it can be claimed and
 279     // then filled.
 280     //
 281     // A region is claimed for processing by atomically changing the
 282     // destination_count to the claimed value (dc_claimed).  After a region has
 283     // been filled, the destination_count should be set to the completed value
 284     // (dc_completed).
 285     inline uint destination_count() const;
 286     inline uint destination_count_raw() const;
 287 
 288     // Whether the block table for this region has been filled.
 289     inline bool blocks_filled() const;
 290 
 291     // Number of times the block table was filled.
 292     DEBUG_ONLY(inline size_t blocks_filled_count() const;)
 293 
 294     // The location of the java heap data that corresponds to this region.
 295     inline HeapWord* data_location() const;
 296 
 297     // The highest address referenced by objects in this region.
 298     inline HeapWord* highest_ref() const;
 299 
 300     // Whether this region is available to be claimed, has been claimed, or has
 301     // been completed.
 302     //
 303     // Minor subtlety:  claimed() returns true if the region is marked
 304     // completed(), which is desirable since a region must be claimed before it
 305     // can be completed.
 306     bool available() const { return _dc_and_los < dc_one; }
 307     bool claimed() const   { return _dc_and_los >= dc_claimed; }
 308     bool completed() const { return _dc_and_los >= dc_completed; }
 309 
 310     // These are not atomic.
 311     void set_destination(HeapWord* addr)       { _destination = addr; }
 312     void set_source_region(size_t region)      { _source_region = region; }
 313     void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
 314     void set_partial_obj_addr(HeapWord* addr)  { _partial_obj_addr = addr; }
 315     void set_partial_obj_size(size_t words)    {
 316       _partial_obj_size = (region_sz_t) words;
 317     }
 318     inline void set_blocks_filled();
 319 
 320     inline void set_destination_count(uint count);
 321     inline void set_live_obj_size(size_t words);
 322     inline void set_data_location(HeapWord* addr);
 323     inline void set_completed();
 324     inline bool claim_unsafe();
 325 
 326     // These are atomic.
 327     inline void add_live_obj(size_t words);
 328     inline void set_highest_ref(HeapWord* addr);
 329     inline void decrement_destination_count();
 330     inline bool claim();
 331 
 332   private:
 333     // The type used to represent object sizes within a region.
 334     typedef uint region_sz_t;
 335 
 336     // Constants for manipulating the _dc_and_los field, which holds both the
 337     // destination count and live obj size.  The live obj size lives at the
 338     // least significant end so no masking is necessary when adding.
 339     static const region_sz_t dc_shift;           // Shift amount.
 340     static const region_sz_t dc_mask;            // Mask for destination count.
 341     static const region_sz_t dc_one;             // 1, shifted appropriately.
 342     static const region_sz_t dc_claimed;         // Region has been claimed.
 343     static const region_sz_t dc_completed;       // Region has been completed.
 344     static const region_sz_t los_mask;           // Mask for live obj size.
 345 
 346     HeapWord*            _destination;
 347     size_t               _source_region;
 348     HeapWord*            _partial_obj_addr;
 349     region_sz_t          _partial_obj_size;
 350     region_sz_t volatile _dc_and_los;
 351     bool                 _blocks_filled;
 352 
 353 #ifdef ASSERT
 354     size_t               _blocks_filled_count;   // Number of block table fills.
 355 
 356     // These enable optimizations that are only partially implemented.  Use
 357     // debug builds to prevent the code fragments from breaking.
 358     HeapWord*            _data_location;
 359     HeapWord*            _highest_ref;
 360 #endif  // #ifdef ASSERT
 361 
 362 #ifdef ASSERT
 363    public:
 364     uint                 _pushed;   // 0 until region is pushed onto a stack
 365    private:
 366 #endif
 367   };
 368 
 369   // "Blocks" allow shorter sections of the bitmap to be searched.  Each Block
 370   // holds an offset, which is the amount of live data in the Region to the left
 371   // of the first live object that starts in the Block.
 372   class BlockData
 373   {
 374   public:
 375     typedef unsigned short int blk_ofs_t;
 376 
 377     blk_ofs_t offset() const    { return _offset; }
 378     void set_offset(size_t val) { _offset = (blk_ofs_t)val; }
 379 
 380   private:
 381     blk_ofs_t _offset;
 382   };
 383 
 384 public:
 385   ParallelCompactData();
 386   bool initialize(MemRegion covered_region);
 387 
 388   size_t region_count() const { return _region_count; }
 389   size_t reserved_byte_size() const { return _reserved_byte_size; }
 390 
 391   // Convert region indices to/from RegionData pointers.
 392   inline RegionData* region(size_t region_idx) const;
 393   inline size_t     region(const RegionData* const region_ptr) const;
 394 
 395   size_t block_count() const { return _block_count; }
 396   inline BlockData* block(size_t block_idx) const;
 397   inline size_t     block(const BlockData* block_ptr) const;
 398 
 399   void add_obj(HeapWord* addr, size_t len);
 400   void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
 401 
 402   // Fill in the regions covering [beg, end) so that no data moves; i.e., the
 403   // destination of region n is simply the start of region n.  The argument beg
 404   // must be region-aligned; end need not be.
 405   void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
 406 
 407   HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info,
 408                                   HeapWord* destination, HeapWord* target_end,
 409                                   HeapWord** target_next);
 410   bool summarize(SplitInfo& split_info,
 411                  HeapWord* source_beg, HeapWord* source_end,
 412                  HeapWord** source_next,
 413                  HeapWord* target_beg, HeapWord* target_end,
 414                  HeapWord** target_next);
 415 
 416   void clear();
 417   void clear_range(size_t beg_region, size_t end_region);
 418   void clear_range(HeapWord* beg, HeapWord* end) {
 419     clear_range(addr_to_region_idx(beg), addr_to_region_idx(end));
 420   }
 421 
 422   // Return the number of words between addr and the start of the region
 423   // containing addr.
 424   inline size_t     region_offset(const HeapWord* addr) const;
 425 
 426   // Convert addresses to/from a region index or region pointer.
 427   inline size_t     addr_to_region_idx(const HeapWord* addr) const;
 428   inline RegionData* addr_to_region_ptr(const HeapWord* addr) const;
 429   inline HeapWord*  region_to_addr(size_t region) const;
 430   inline HeapWord*  region_to_addr(size_t region, size_t offset) const;
 431   inline HeapWord*  region_to_addr(const RegionData* region) const;
 432 
 433   inline HeapWord*  region_align_down(HeapWord* addr) const;
 434   inline HeapWord*  region_align_up(HeapWord* addr) const;
 435   inline bool       is_region_aligned(HeapWord* addr) const;
 436 
 437   // Analogous to region_offset() for blocks.
 438   size_t     block_offset(const HeapWord* addr) const;
 439   size_t     addr_to_block_idx(const HeapWord* addr) const;
 440   size_t     addr_to_block_idx(const oop obj) const {
 441     return addr_to_block_idx((HeapWord*) obj);
 442   }
 443   inline BlockData* addr_to_block_ptr(const HeapWord* addr) const;
 444   inline HeapWord*  block_to_addr(size_t block) const;
 445   inline size_t     region_to_block_idx(size_t region) const;
 446 
 447   inline HeapWord*  block_align_down(HeapWord* addr) const;
 448   inline HeapWord*  block_align_up(HeapWord* addr) const;
 449   inline bool       is_block_aligned(HeapWord* addr) const;
 450 
 451   // Return the address one past the end of the partial object.
 452   HeapWord* partial_obj_end(size_t region_idx) const;
 453 
 454   // Return the location of the object after compaction.
 455   HeapWord* calc_new_pointer(HeapWord* addr);
 456 
 457   HeapWord* calc_new_pointer(oop p) {
 458     return calc_new_pointer((HeapWord*) p);
 459   }
 460 
 461 #ifdef  ASSERT
 462   void verify_clear(const PSVirtualSpace* vspace);
 463   void verify_clear();
 464 #endif  // #ifdef ASSERT
 465 
 466 private:
 467   bool initialize_block_data();
 468   bool initialize_region_data(size_t region_size);
 469   PSVirtualSpace* create_vspace(size_t count, size_t element_size);
 470 
 471 private:
 472   HeapWord*       _region_start;
 473 #ifdef  ASSERT
 474   HeapWord*       _region_end;
 475 #endif  // #ifdef ASSERT
 476 
 477   PSVirtualSpace* _region_vspace;
 478   size_t          _reserved_byte_size;
 479   RegionData*     _region_data;
 480   size_t          _region_count;
 481 
 482   PSVirtualSpace* _block_vspace;
 483   BlockData*      _block_data;
 484   size_t          _block_count;
 485 };
 486 
 487 inline uint
 488 ParallelCompactData::RegionData::destination_count_raw() const
 489 {
 490   return _dc_and_los & dc_mask;
 491 }
 492 
 493 inline uint
 494 ParallelCompactData::RegionData::destination_count() const
 495 {
 496   return destination_count_raw() >> dc_shift;
 497 }
 498 
 499 inline bool
 500 ParallelCompactData::RegionData::blocks_filled() const
 501 {
 502   return _blocks_filled;
 503 }
 504 
 505 #ifdef ASSERT
 506 inline size_t
 507 ParallelCompactData::RegionData::blocks_filled_count() const
 508 {
 509   return _blocks_filled_count;
 510 }
 511 #endif // #ifdef ASSERT
 512 
 513 inline void
 514 ParallelCompactData::RegionData::set_blocks_filled()
 515 {
 516   _blocks_filled = true;
 517   // Debug builds count the number of times the table was filled.
 518   DEBUG_ONLY(Atomic::inc_ptr(&_blocks_filled_count));
 519 }
 520 
 521 inline void
 522 ParallelCompactData::RegionData::set_destination_count(uint count)
 523 {
 524   assert(count <= (dc_completed >> dc_shift), "count too large");
 525   const region_sz_t live_sz = (region_sz_t) live_obj_size();
 526   _dc_and_los = (count << dc_shift) | live_sz;
 527 }
 528 
 529 inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words)
 530 {
 531   assert(words <= los_mask, "would overflow");
 532   _dc_and_los = destination_count_raw() | (region_sz_t)words;
 533 }
 534 
 535 inline void ParallelCompactData::RegionData::decrement_destination_count()
 536 {
 537   assert(_dc_and_los < dc_claimed, "already claimed");
 538   assert(_dc_and_los >= dc_one, "count would go negative");
 539   Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
 540 }
 541 
 542 inline HeapWord* ParallelCompactData::RegionData::data_location() const
 543 {
 544   DEBUG_ONLY(return _data_location;)
 545   NOT_DEBUG(return NULL;)
 546 }
 547 
 548 inline HeapWord* ParallelCompactData::RegionData::highest_ref() const
 549 {
 550   DEBUG_ONLY(return _highest_ref;)
 551   NOT_DEBUG(return NULL;)
 552 }
 553 
 554 inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr)
 555 {
 556   DEBUG_ONLY(_data_location = addr;)
 557 }
 558 
 559 inline void ParallelCompactData::RegionData::set_completed()
 560 {
 561   assert(claimed(), "must be claimed first");
 562   _dc_and_los = dc_completed | (region_sz_t) live_obj_size();
 563 }
 564 
 565 // MT-unsafe claiming of a region.  Should only be used during single threaded
 566 // execution.
 567 inline bool ParallelCompactData::RegionData::claim_unsafe()
 568 {
 569   if (available()) {
 570     _dc_and_los |= dc_claimed;
 571     return true;
 572   }
 573   return false;
 574 }
 575 
 576 inline void ParallelCompactData::RegionData::add_live_obj(size_t words)
 577 {
 578   assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
 579   Atomic::add((int) words, (volatile int*) &_dc_and_los);
 580 }
 581 
 582 inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr)
 583 {
 584 #ifdef ASSERT
 585   HeapWord* tmp = _highest_ref;
 586   while (addr > tmp) {
 587     tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
 588   }
 589 #endif  // #ifdef ASSERT
 590 }
 591 
 592 inline bool ParallelCompactData::RegionData::claim()
 593 {
 594   const int los = (int) live_obj_size();
 595   const int old = Atomic::cmpxchg(dc_claimed | los,
 596                                   (volatile int*) &_dc_and_los, los);
 597   return old == los;
 598 }
 599 
 600 inline ParallelCompactData::RegionData*
 601 ParallelCompactData::region(size_t region_idx) const
 602 {
 603   assert(region_idx <= region_count(), "bad arg");
 604   return _region_data + region_idx;
 605 }
 606 
 607 inline size_t
 608 ParallelCompactData::region(const RegionData* const region_ptr) const
 609 {
 610   assert(region_ptr >= _region_data, "bad arg");
 611   assert(region_ptr <= _region_data + region_count(), "bad arg");
 612   return pointer_delta(region_ptr, _region_data, sizeof(RegionData));
 613 }
 614 
 615 inline ParallelCompactData::BlockData*
 616 ParallelCompactData::block(size_t n) const {
 617   assert(n < block_count(), "bad arg");
 618   return _block_data + n;
 619 }
 620 
 621 inline size_t
 622 ParallelCompactData::region_offset(const HeapWord* addr) const
 623 {
 624   assert(addr >= _region_start, "bad addr");
 625   assert(addr <= _region_end, "bad addr");
 626   return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize;
 627 }
 628 
 629 inline size_t
 630 ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const
 631 {
 632   assert(addr >= _region_start, "bad addr");
 633   assert(addr <= _region_end, "bad addr");
 634   return pointer_delta(addr, _region_start) >> Log2RegionSize;
 635 }
 636 
 637 inline ParallelCompactData::RegionData*
 638 ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const
 639 {
 640   return region(addr_to_region_idx(addr));
 641 }
 642 
 643 inline HeapWord*
 644 ParallelCompactData::region_to_addr(size_t region) const
 645 {
 646   assert(region <= _region_count, "region out of range");
 647   return _region_start + (region << Log2RegionSize);
 648 }
 649 
 650 inline HeapWord*
 651 ParallelCompactData::region_to_addr(const RegionData* region) const
 652 {
 653   return region_to_addr(pointer_delta(region, _region_data,
 654                                       sizeof(RegionData)));
 655 }
 656 
 657 inline HeapWord*
 658 ParallelCompactData::region_to_addr(size_t region, size_t offset) const
 659 {
 660   assert(region <= _region_count, "region out of range");
 661   assert(offset < RegionSize, "offset too big");  // This may be too strict.
 662   return region_to_addr(region) + offset;
 663 }
 664 
 665 inline HeapWord*
 666 ParallelCompactData::region_align_down(HeapWord* addr) const
 667 {
 668   assert(addr >= _region_start, "bad addr");
 669   assert(addr < _region_end + RegionSize, "bad addr");
 670   return (HeapWord*)(size_t(addr) & RegionAddrMask);
 671 }
 672 
 673 inline HeapWord*
 674 ParallelCompactData::region_align_up(HeapWord* addr) const
 675 {
 676   assert(addr >= _region_start, "bad addr");
 677   assert(addr <= _region_end, "bad addr");
 678   return region_align_down(addr + RegionSizeOffsetMask);
 679 }
 680 
 681 inline bool
 682 ParallelCompactData::is_region_aligned(HeapWord* addr) const
 683 {
 684   return region_offset(addr) == 0;
 685 }
 686 
 687 inline size_t
 688 ParallelCompactData::block_offset(const HeapWord* addr) const
 689 {
 690   assert(addr >= _region_start, "bad addr");
 691   assert(addr <= _region_end, "bad addr");
 692   return (size_t(addr) & BlockAddrOffsetMask) >> LogHeapWordSize;
 693 }
 694 
 695 inline size_t
 696 ParallelCompactData::addr_to_block_idx(const HeapWord* addr) const
 697 {
 698   assert(addr >= _region_start, "bad addr");
 699   assert(addr <= _region_end, "bad addr");
 700   return pointer_delta(addr, _region_start) >> Log2BlockSize;
 701 }
 702 
 703 inline ParallelCompactData::BlockData*
 704 ParallelCompactData::addr_to_block_ptr(const HeapWord* addr) const
 705 {
 706   return block(addr_to_block_idx(addr));
 707 }
 708 
 709 inline HeapWord*
 710 ParallelCompactData::block_to_addr(size_t block) const
 711 {
 712   assert(block < _block_count, "block out of range");
 713   return _region_start + (block << Log2BlockSize);
 714 }
 715 
 716 inline size_t
 717 ParallelCompactData::region_to_block_idx(size_t region) const
 718 {
 719   return region << Log2BlocksPerRegion;
 720 }
 721 
 722 inline HeapWord*
 723 ParallelCompactData::block_align_down(HeapWord* addr) const
 724 {
 725   assert(addr >= _region_start, "bad addr");
 726   assert(addr < _region_end + RegionSize, "bad addr");
 727   return (HeapWord*)(size_t(addr) & BlockAddrMask);
 728 }
 729 
 730 inline HeapWord*
 731 ParallelCompactData::block_align_up(HeapWord* addr) const
 732 {
 733   assert(addr >= _region_start, "bad addr");
 734   assert(addr <= _region_end, "bad addr");
 735   return block_align_down(addr + BlockSizeOffsetMask);
 736 }
 737 
 738 inline bool
 739 ParallelCompactData::is_block_aligned(HeapWord* addr) const
 740 {
 741   return block_offset(addr) == 0;
 742 }
 743 
 744 // Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
 745 // do_addr() method.
 746 //
 747 // The closure is initialized with the number of heap words to process
 748 // (words_remaining()), and becomes 'full' when it reaches 0.  The do_addr()
 749 // methods in subclasses should update the total as words are processed.  Since
 750 // only one subclass actually uses this mechanism to terminate iteration, the
 751 // default initial value is > 0.  The implementation is here and not in the
 752 // single subclass that uses it to avoid making is_full() virtual, and thus
 753 // adding a virtual call per live object.
 754 
 755 class ParMarkBitMapClosure: public StackObj {
 756  public:
 757   typedef ParMarkBitMap::idx_t idx_t;
 758   typedef ParMarkBitMap::IterationStatus IterationStatus;
 759 
 760  public:
 761   inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
 762                               size_t words = max_uintx);
 763 
 764   inline ParCompactionManager* compaction_manager() const;
 765   inline ParMarkBitMap*        bitmap() const;
 766   inline size_t                words_remaining() const;
 767   inline bool                  is_full() const;
 768   inline HeapWord*             source() const;
 769 
 770   inline void                  set_source(HeapWord* addr);
 771 
 772   virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
 773 
 774  protected:
 775   inline void decrement_words_remaining(size_t words);
 776 
 777  private:
 778   ParMarkBitMap* const        _bitmap;
 779   ParCompactionManager* const _compaction_manager;
 780   DEBUG_ONLY(const size_t     _initial_words_remaining;) // Useful in debugger.
 781   size_t                      _words_remaining; // Words left to copy.
 782 
 783  protected:
 784   HeapWord*                   _source;          // Next addr that would be read.
 785 };
 786 
 787 inline
 788 ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
 789                                            ParCompactionManager* cm,
 790                                            size_t words):
 791   _bitmap(bitmap), _compaction_manager(cm)
 792 #ifdef  ASSERT
 793   , _initial_words_remaining(words)
 794 #endif
 795 {
 796   _words_remaining = words;
 797   _source = NULL;
 798 }
 799 
 800 inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
 801   return _compaction_manager;
 802 }
 803 
 804 inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
 805   return _bitmap;
 806 }
 807 
 808 inline size_t ParMarkBitMapClosure::words_remaining() const {
 809   return _words_remaining;
 810 }
 811 
 812 inline bool ParMarkBitMapClosure::is_full() const {
 813   return words_remaining() == 0;
 814 }
 815 
 816 inline HeapWord* ParMarkBitMapClosure::source() const {
 817   return _source;
 818 }
 819 
 820 inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
 821   _source = addr;
 822 }
 823 
 824 inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
 825   assert(_words_remaining >= words, "processed too many words");
 826   _words_remaining -= words;
 827 }
 828 
 829 // The UseParallelOldGC collector is a stop-the-world garbage collector that
 830 // does parts of the collection using parallel threads.  The collection includes
 831 // the tenured generation and the young generation.  The permanent generation is
 832 // collected at the same time as the other two generations but the permanent
 833 // generation is collect by a single GC thread.  The permanent generation is
 834 // collected serially because of the requirement that during the processing of a
 835 // klass AAA, any objects reference by AAA must already have been processed.
 836 // This requirement is enforced by a left (lower address) to right (higher
 837 // address) sliding compaction.
 838 //
 839 // There are four phases of the collection.
 840 //
 841 //      - marking phase
 842 //      - summary phase
 843 //      - compacting phase
 844 //      - clean up phase
 845 //
 846 // Roughly speaking these phases correspond, respectively, to
 847 //      - mark all the live objects
 848 //      - calculate the destination of each object at the end of the collection
 849 //      - move the objects to their destination
 850 //      - update some references and reinitialize some variables
 851 //
 852 // These three phases are invoked in PSParallelCompact::invoke_no_policy().  The
 853 // marking phase is implemented in PSParallelCompact::marking_phase() and does a
 854 // complete marking of the heap.  The summary phase is implemented in
 855 // PSParallelCompact::summary_phase().  The move and update phase is implemented
 856 // in PSParallelCompact::compact().
 857 //
 858 // A space that is being collected is divided into regions and with each region
 859 // is associated an object of type ParallelCompactData.  Each region is of a
 860 // fixed size and typically will contain more than 1 object and may have parts
 861 // of objects at the front and back of the region.
 862 //
 863 // region            -----+---------------------+----------
 864 // objects covered   [ AAA  )[ BBB )[ CCC   )[ DDD     )
 865 //
 866 // The marking phase does a complete marking of all live objects in the heap.
 867 // The marking also compiles the size of the data for all live objects covered
 868 // by the region.  This size includes the part of any live object spanning onto
 869 // the region (part of AAA if it is live) from the front, all live objects
 870 // contained in the region (BBB and/or CCC if they are live), and the part of
 871 // any live objects covered by the region that extends off the region (part of
 872 // DDD if it is live).  The marking phase uses multiple GC threads and marking
 873 // is done in a bit array of type ParMarkBitMap.  The marking of the bit map is
 874 // done atomically as is the accumulation of the size of the live objects
 875 // covered by a region.
 876 //
 877 // The summary phase calculates the total live data to the left of each region
 878 // XXX.  Based on that total and the bottom of the space, it can calculate the
 879 // starting location of the live data in XXX.  The summary phase calculates for
 880 // each region XXX quantities such as
 881 //
 882 //      - the amount of live data at the beginning of a region from an object
 883 //        entering the region.
 884 //      - the location of the first live data on the region
 885 //      - a count of the number of regions receiving live data from XXX.
 886 //
 887 // See ParallelCompactData for precise details.  The summary phase also
 888 // calculates the dense prefix for the compaction.  The dense prefix is a
 889 // portion at the beginning of the space that is not moved.  The objects in the
 890 // dense prefix do need to have their object references updated.  See method
 891 // summarize_dense_prefix().
 892 //
 893 // The summary phase is done using 1 GC thread.
 894 //
 895 // The compaction phase moves objects to their new location and updates all
 896 // references in the object.
 897 //
 898 // A current exception is that objects that cross a region boundary are moved
 899 // but do not have their references updated.  References are not updated because
 900 // it cannot easily be determined if the klass pointer KKK for the object AAA
 901 // has been updated.  KKK likely resides in a region to the left of the region
 902 // containing AAA.  These AAA's have there references updated at the end in a
 903 // clean up phase.  See the method PSParallelCompact::update_deferred_objects().
 904 // An alternate strategy is being investigated for this deferral of updating.
 905 //
 906 // Compaction is done on a region basis.  A region that is ready to be filled is
 907 // put on a ready list and GC threads take region off the list and fill them.  A
 908 // region is ready to be filled if it empty of live objects.  Such a region may
 909 // have been initially empty (only contained dead objects) or may have had all
 910 // its live objects copied out already.  A region that compacts into itself is
 911 // also ready for filling.  The ready list is initially filled with empty
 912 // regions and regions compacting into themselves.  There is always at least 1
 913 // region that can be put on the ready list.  The regions are atomically added
 914 // and removed from the ready list.
 915 
 916 class PSParallelCompact : AllStatic {
 917  public:
 918   // Convenient access to type names.
 919   typedef ParMarkBitMap::idx_t idx_t;
 920   typedef ParallelCompactData::RegionData RegionData;
 921   typedef ParallelCompactData::BlockData BlockData;
 922 
 923   typedef enum {
 924     old_space_id, eden_space_id,
 925     from_space_id, to_space_id, last_space_id
 926   } SpaceId;
 927 
 928  public:
 929   // Inline closure decls
 930   //
 931   class IsAliveClosure: public BoolObjectClosure {
 932    public:
 933     virtual bool do_object_b(oop p);
 934   };
 935 
 936   class FollowStackClosure: public VoidClosure {
 937    private:
 938     ParCompactionManager* _compaction_manager;
 939    public:
 940     FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
 941     virtual void do_void();
 942   };
 943 
 944   class AdjustPointerClosure: public ExtendedOopClosure {
 945    public:
 946     template <typename T> void do_oop_nv(T* p);
 947     virtual void do_oop(oop* p);
 948     virtual void do_oop(narrowOop* p);
 949 
 950     // This closure provides its own oop verification code.
 951     debug_only(virtual bool should_verify_oops() { return false; })
 952   };
 953 
 954   class AdjustKlassClosure : public KlassClosure {
 955    public:
 956     void do_klass(Klass* klass);
 957   };
 958 
 959   friend class FollowStackClosure;
 960   friend class AdjustPointerClosure;
 961   friend class AdjustKlassClosure;
 962   friend class FollowKlassClosure;
 963   friend class InstanceClassLoaderKlass;
 964   friend class RefProcTaskProxy;
 965 
 966  private:
 967   static STWGCTimer           _gc_timer;
 968   static ParallelOldTracer    _gc_tracer;
 969   static elapsedTimer         _accumulated_time;
 970   static unsigned int         _total_invocations;
 971   static unsigned int         _maximum_compaction_gc_num;
 972   static jlong                _time_of_last_gc;   // ms
 973   static CollectorCounters*   _counters;
 974   static ParMarkBitMap        _mark_bitmap;
 975   static ParallelCompactData  _summary_data;
 976   static IsAliveClosure       _is_alive_closure;
 977   static SpaceInfo            _space_info[last_space_id];
 978   static bool                 _print_phases;
 979   static AdjustPointerClosure _adjust_pointer_closure;
 980   static AdjustKlassClosure   _adjust_klass_closure;
 981 
 982   // Reference processing (used in ...follow_contents)
 983   static ReferenceProcessor*  _ref_processor;
 984 
 985   // Updated location of intArrayKlassObj.
 986   static Klass* _updated_int_array_klass_obj;
 987 
 988   // Values computed at initialization and used by dead_wood_limiter().
 989   static double _dwl_mean;
 990   static double _dwl_std_dev;
 991   static double _dwl_first_term;
 992   static double _dwl_adjustment;
 993 #ifdef  ASSERT
 994   static bool   _dwl_initialized;
 995 #endif  // #ifdef ASSERT
 996 
 997 
 998  public:
 999   static ParallelOldTracer* gc_tracer() { return &_gc_tracer; }
1000 
1001  private:
1002 
1003   static void initialize_space_info();
1004 
1005   // Return true if details about individual phases should be printed.
1006   static inline bool print_phases();
1007 
1008   // Clear the marking bitmap and summary data that cover the specified space.
1009   static void clear_data_covering_space(SpaceId id);
1010 
1011   static void pre_compact(PreGCValues* pre_gc_values);
1012   static void post_compact();
1013 
1014   // Mark live objects
1015   static void marking_phase(ParCompactionManager* cm,
1016                             bool maximum_heap_compaction,
1017                             ParallelOldTracer *gc_tracer);
1018 
1019   // Compute the dense prefix for the designated space.  This is an experimental
1020   // implementation currently not used in production.
1021   static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
1022                                                     bool maximum_compaction);
1023 
1024   // Methods used to compute the dense prefix.
1025 
1026   // Compute the value of the normal distribution at x = density.  The mean and
1027   // standard deviation are values saved by initialize_dead_wood_limiter().
1028   static inline double normal_distribution(double density);
1029 
1030   // Initialize the static vars used by dead_wood_limiter().
1031   static void initialize_dead_wood_limiter();
1032 
1033   // Return the percentage of space that can be treated as "dead wood" (i.e.,
1034   // not reclaimed).
1035   static double dead_wood_limiter(double density, size_t min_percent);
1036 
1037   // Find the first (left-most) region in the range [beg, end) that has at least
1038   // dead_words of dead space to the left.  The argument beg must be the first
1039   // region in the space that is not completely live.
1040   static RegionData* dead_wood_limit_region(const RegionData* beg,
1041                                             const RegionData* end,
1042                                             size_t dead_words);
1043 
1044   // Return a pointer to the first region in the range [beg, end) that is not
1045   // completely full.
1046   static RegionData* first_dead_space_region(const RegionData* beg,
1047                                              const RegionData* end);
1048 
1049   // Return a value indicating the benefit or 'yield' if the compacted region
1050   // were to start (or equivalently if the dense prefix were to end) at the
1051   // candidate region.  Higher values are better.
1052   //
1053   // The value is based on the amount of space reclaimed vs. the costs of (a)
1054   // updating references in the dense prefix plus (b) copying objects and
1055   // updating references in the compacted region.
1056   static inline double reclaimed_ratio(const RegionData* const candidate,
1057                                        HeapWord* const bottom,
1058                                        HeapWord* const top,
1059                                        HeapWord* const new_top);
1060 
1061   // Compute the dense prefix for the designated space.
1062   static HeapWord* compute_dense_prefix(const SpaceId id,
1063                                         bool maximum_compaction);
1064 
1065   // Return true if dead space crosses onto the specified Region; bit must be
1066   // the bit index corresponding to the first word of the Region.
1067   static inline bool dead_space_crosses_boundary(const RegionData* region,
1068                                                  idx_t bit);
1069 
1070   // Summary phase utility routine to fill dead space (if any) at the dense
1071   // prefix boundary.  Should only be called if the the dense prefix is
1072   // non-empty.
1073   static void fill_dense_prefix_end(SpaceId id);
1074 
1075   // Clear the summary data source_region field for the specified addresses.
1076   static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
1077 
1078 #ifndef PRODUCT
1079   // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
1080 
1081   // Fill the region [start, start + words) with live object(s).  Only usable
1082   // for the old and permanent generations.
1083   static void fill_with_live_objects(SpaceId id, HeapWord* const start,
1084                                      size_t words);
1085   // Include the new objects in the summary data.
1086   static void summarize_new_objects(SpaceId id, HeapWord* start);
1087 
1088   // Add live objects to a survivor space since it's rare that both survivors
1089   // are non-empty.
1090   static void provoke_split_fill_survivor(SpaceId id);
1091 
1092   // Add live objects and/or choose the dense prefix to provoke splitting.
1093   static void provoke_split(bool & maximum_compaction);
1094 #endif
1095 
1096   static void summarize_spaces_quick();
1097   static void summarize_space(SpaceId id, bool maximum_compaction);
1098   static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
1099 
1100   // Adjust addresses in roots.  Does not adjust addresses in heap.
1101   static void adjust_roots();
1102 
1103   DEBUG_ONLY(static void write_block_fill_histogram(outputStream* const out);)
1104 
1105   // Move objects to new locations.
1106   static void compact_perm(ParCompactionManager* cm);
1107   static void compact();
1108 
1109   // Add available regions to the stack and draining tasks to the task queue.
1110   static void enqueue_region_draining_tasks(GCTaskQueue* q,
1111                                             uint parallel_gc_threads);
1112 
1113   // Add dense prefix update tasks to the task queue.
1114   static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
1115                                          uint parallel_gc_threads);
1116 
1117   // Add region stealing tasks to the task queue.
1118   static void enqueue_region_stealing_tasks(
1119                                        GCTaskQueue* q,
1120                                        ParallelTaskTerminator* terminator_ptr,
1121                                        uint parallel_gc_threads);
1122 
1123   // If objects are left in eden after a collection, try to move the boundary
1124   // and absorb them into the old gen.  Returns true if eden was emptied.
1125   static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
1126                                          PSYoungGen* young_gen,
1127                                          PSOldGen* old_gen);
1128 
1129   // Reset time since last full gc
1130   static void reset_millis_since_last_gc();
1131 
1132  public:
1133   class MarkAndPushClosure: public ExtendedOopClosure {
1134    private:
1135     ParCompactionManager* _compaction_manager;
1136    public:
1137     MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
1138 
1139     template <typename T> void do_oop_nv(T* p);
1140     virtual void do_oop(oop* p);
1141     virtual void do_oop(narrowOop* p);
1142 
1143     // This closure provides its own oop verification code.
1144     debug_only(virtual bool should_verify_oops() { return false; })
1145   };
1146 
1147   // The one and only place to start following the classes.
1148   // Should only be applied to the ClassLoaderData klasses list.
1149   class FollowKlassClosure : public KlassClosure {
1150    private:
1151     MarkAndPushClosure* _mark_and_push_closure;
1152    public:
1153     FollowKlassClosure(MarkAndPushClosure* mark_and_push_closure) :
1154         _mark_and_push_closure(mark_and_push_closure) { }
1155     void do_klass(Klass* klass);
1156   };
1157 
1158   PSParallelCompact();
1159 
1160   static void invoke(bool maximum_heap_compaction);
1161   static bool invoke_no_policy(bool maximum_heap_compaction);
1162 
1163   static void post_initialize();
1164   // Perform initialization for PSParallelCompact that requires
1165   // allocations.  This should be called during the VM initialization
1166   // at a pointer where it would be appropriate to return a JNI_ENOMEM
1167   // in the event of a failure.
1168   static bool initialize();
1169 
1170   // Closure accessors
1171   static PSParallelCompact::AdjustPointerClosure* adjust_pointer_closure() {
1172     return &_adjust_pointer_closure;
1173   }
1174   static KlassClosure* adjust_klass_closure()      { return (KlassClosure*)&_adjust_klass_closure; }
1175   static BoolObjectClosure* is_alive_closure()     { return (BoolObjectClosure*)&_is_alive_closure; }
1176 
1177   // Public accessors
1178   static elapsedTimer* accumulated_time() { return &_accumulated_time; }
1179   static unsigned int total_invocations() { return _total_invocations; }
1180   static CollectorCounters* counters()    { return _counters; }
1181 
1182   // Used to add tasks
1183   static GCTaskManager* const gc_task_manager();
1184   static Klass* updated_int_array_klass_obj() {
1185     return _updated_int_array_klass_obj;
1186   }
1187 
1188   // Marking support
1189   static inline bool mark_obj(oop obj);
1190   static inline bool is_marked(oop obj);
1191   // Check mark and maybe push on marking stack
1192   template <class T> static inline void mark_and_push(ParCompactionManager* cm,
1193                                                       T* p);
1194   template <class T> static inline void adjust_pointer(T* p);
1195 
1196   static inline void follow_klass(ParCompactionManager* cm, Klass* klass);
1197 
1198   static void follow_class_loader(ParCompactionManager* cm,
1199                                   ClassLoaderData* klass);
1200 
1201   // Compaction support.
1202   // Return true if p is in the range [beg_addr, end_addr).
1203   static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
1204   static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
1205 
1206   // Convenience wrappers for per-space data kept in _space_info.
1207   static inline MutableSpace*     space(SpaceId space_id);
1208   static inline HeapWord*         new_top(SpaceId space_id);
1209   static inline HeapWord*         dense_prefix(SpaceId space_id);
1210   static inline ObjectStartArray* start_array(SpaceId space_id);
1211 
1212   // Move and update the live objects in the specified space.
1213   static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
1214 
1215   // Process the end of the given region range in the dense prefix.
1216   // This includes saving any object not updated.
1217   static void dense_prefix_regions_epilogue(ParCompactionManager* cm,
1218                                             size_t region_start_index,
1219                                             size_t region_end_index,
1220                                             idx_t exiting_object_offset,
1221                                             idx_t region_offset_start,
1222                                             idx_t region_offset_end);
1223 
1224   // Update a region in the dense prefix.  For each live object
1225   // in the region, update it's interior references.  For each
1226   // dead object, fill it with deadwood. Dead space at the end
1227   // of a region range will be filled to the start of the next
1228   // live object regardless of the region_index_end.  None of the
1229   // objects in the dense prefix move and dead space is dead
1230   // (holds only dead objects that don't need any processing), so
1231   // dead space can be filled in any order.
1232   static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
1233                                                   SpaceId space_id,
1234                                                   size_t region_index_start,
1235                                                   size_t region_index_end);
1236 
1237   // Return the address of the count + 1st live word in the range [beg, end).
1238   static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
1239 
1240   // Return the address of the word to be copied to dest_addr, which must be
1241   // aligned to a region boundary.
1242   static HeapWord* first_src_addr(HeapWord* const dest_addr,
1243                                   SpaceId src_space_id,
1244                                   size_t src_region_idx);
1245 
1246   // Determine the next source region, set closure.source() to the start of the
1247   // new region return the region index.  Parameter end_addr is the address one
1248   // beyond the end of source range just processed.  If necessary, switch to a
1249   // new source space and set src_space_id (in-out parameter) and src_space_top
1250   // (out parameter) accordingly.
1251   static size_t next_src_region(MoveAndUpdateClosure& closure,
1252                                 SpaceId& src_space_id,
1253                                 HeapWord*& src_space_top,
1254                                 HeapWord* end_addr);
1255 
1256   // Decrement the destination count for each non-empty source region in the
1257   // range [beg_region, region(region_align_up(end_addr))).  If the destination
1258   // count for a region goes to 0 and it needs to be filled, enqueue it.
1259   static void decrement_destination_counts(ParCompactionManager* cm,
1260                                            SpaceId src_space_id,
1261                                            size_t beg_region,
1262                                            HeapWord* end_addr);
1263 
1264   // Fill a region, copying objects from one or more source regions.
1265   static void fill_region(ParCompactionManager* cm, size_t region_idx);
1266   static void fill_and_update_region(ParCompactionManager* cm, size_t region) {
1267     fill_region(cm, region);
1268   }
1269 
1270   // Fill in the block table for the specified region.
1271   static void fill_blocks(size_t region_idx);
1272 
1273   // Update the deferred objects in the space.
1274   static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
1275 
1276   static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
1277   static ParallelCompactData& summary_data() { return _summary_data; }
1278 
1279   // Reference Processing
1280   static ReferenceProcessor* const ref_processor() { return _ref_processor; }
1281 
1282   static STWGCTimer* gc_timer() { return &_gc_timer; }
1283 
1284   // Return the SpaceId for the given address.
1285   static SpaceId space_id(HeapWord* addr);
1286 
1287   // Time since last full gc (in milliseconds).
1288   static jlong millis_since_last_gc();
1289 
1290   static void print_on_error(outputStream* st);
1291 
1292 #ifndef PRODUCT
1293   // Debugging support.
1294   static const char* space_names[last_space_id];
1295   static void print_region_ranges();
1296   static void print_dense_prefix_stats(const char* const algorithm,
1297                                        const SpaceId id,
1298                                        const bool maximum_compaction,
1299                                        HeapWord* const addr);
1300   static void summary_phase_msg(SpaceId dst_space_id,
1301                                 HeapWord* dst_beg, HeapWord* dst_end,
1302                                 SpaceId src_space_id,
1303                                 HeapWord* src_beg, HeapWord* src_end);
1304 #endif  // #ifndef PRODUCT
1305 
1306 #ifdef  ASSERT
1307   // Sanity check the new location of a word in the heap.
1308   static inline void check_new_location(HeapWord* old_addr, HeapWord* new_addr);
1309   // Verify that all the regions have been emptied.
1310   static void verify_complete(SpaceId space_id);
1311 #endif  // #ifdef ASSERT
1312 };
1313 
1314 inline bool PSParallelCompact::mark_obj(oop obj) {
1315   const int obj_size = obj->size();
1316   if (mark_bitmap()->mark_obj(obj, obj_size)) {
1317     _summary_data.add_obj(obj, obj_size);
1318     return true;
1319   } else {
1320     return false;
1321   }
1322 }
1323 
1324 inline bool PSParallelCompact::is_marked(oop obj) {
1325   return mark_bitmap()->is_marked(obj);
1326 }
1327 
1328 inline bool PSParallelCompact::print_phases() {
1329   return _print_phases;
1330 }
1331 
1332 inline double PSParallelCompact::normal_distribution(double density) {
1333   assert(_dwl_initialized, "uninitialized");
1334   const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
1335   return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
1336 }
1337 
1338 inline bool
1339 PSParallelCompact::dead_space_crosses_boundary(const RegionData* region,
1340                                                idx_t bit)
1341 {
1342   assert(bit > 0, "cannot call this for the first bit/region");
1343   assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit),
1344          "sanity check");
1345 
1346   // Dead space crosses the boundary if (1) a partial object does not extend
1347   // onto the region, (2) an object does not start at the beginning of the
1348   // region, and (3) an object does not end at the end of the prior region.
1349   return region->partial_obj_size() == 0 &&
1350     !_mark_bitmap.is_obj_beg(bit) &&
1351     !_mark_bitmap.is_obj_end(bit - 1);
1352 }
1353 
1354 inline bool
1355 PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
1356   return p >= beg_addr && p < end_addr;
1357 }
1358 
1359 inline bool
1360 PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
1361   return is_in((HeapWord*)p, beg_addr, end_addr);
1362 }
1363 
1364 inline MutableSpace* PSParallelCompact::space(SpaceId id) {
1365   assert(id < last_space_id, "id out of range");
1366   return _space_info[id].space();
1367 }
1368 
1369 inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
1370   assert(id < last_space_id, "id out of range");
1371   return _space_info[id].new_top();
1372 }
1373 
1374 inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
1375   assert(id < last_space_id, "id out of range");
1376   return _space_info[id].dense_prefix();
1377 }
1378 
1379 inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
1380   assert(id < last_space_id, "id out of range");
1381   return _space_info[id].start_array();
1382 }
1383 
1384 #ifdef ASSERT
1385 inline void
1386 PSParallelCompact::check_new_location(HeapWord* old_addr, HeapWord* new_addr)
1387 {
1388   assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr),
1389          "must move left or to a different space");
1390   assert(is_object_aligned((intptr_t)old_addr) && is_object_aligned((intptr_t)new_addr),
1391          "checking alignment");
1392 }
1393 #endif // ASSERT
1394 
1395 class MoveAndUpdateClosure: public ParMarkBitMapClosure {
1396  public:
1397   inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
1398                               ObjectStartArray* start_array,
1399                               HeapWord* destination, size_t words);
1400 
1401   // Accessors.
1402   HeapWord* destination() const         { return _destination; }
1403 
1404   // If the object will fit (size <= words_remaining()), copy it to the current
1405   // destination, update the interior oops and the start array and return either
1406   // full (if the closure is full) or incomplete.  If the object will not fit,
1407   // return would_overflow.
1408   virtual IterationStatus do_addr(HeapWord* addr, size_t size);
1409 
1410   // Copy enough words to fill this closure, starting at source().  Interior
1411   // oops and the start array are not updated.  Return full.
1412   IterationStatus copy_until_full();
1413 
1414   // Copy enough words to fill this closure or to the end of an object,
1415   // whichever is smaller, starting at source().  Interior oops and the start
1416   // array are not updated.
1417   void copy_partial_obj();
1418 
1419  protected:
1420   // Update variables to indicate that word_count words were processed.
1421   inline void update_state(size_t word_count);
1422 
1423  protected:
1424   ObjectStartArray* const _start_array;
1425   HeapWord*               _destination;         // Next addr to be written.
1426 };
1427 
1428 inline
1429 MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
1430                                            ParCompactionManager* cm,
1431                                            ObjectStartArray* start_array,
1432                                            HeapWord* destination,
1433                                            size_t words) :
1434   ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
1435 {
1436   _destination = destination;
1437 }
1438 
1439 inline void MoveAndUpdateClosure::update_state(size_t words)
1440 {
1441   decrement_words_remaining(words);
1442   _source += words;
1443   _destination += words;
1444 }
1445 
1446 class UpdateOnlyClosure: public ParMarkBitMapClosure {
1447  private:
1448   const PSParallelCompact::SpaceId _space_id;
1449   ObjectStartArray* const          _start_array;
1450 
1451  public:
1452   UpdateOnlyClosure(ParMarkBitMap* mbm,
1453                     ParCompactionManager* cm,
1454                     PSParallelCompact::SpaceId space_id);
1455 
1456   // Update the object.
1457   virtual IterationStatus do_addr(HeapWord* addr, size_t words);
1458 
1459   inline void do_addr(HeapWord* addr);
1460 };
1461 
1462 class FillClosure: public ParMarkBitMapClosure
1463 {
1464 public:
1465   FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
1466     ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
1467     _start_array(PSParallelCompact::start_array(space_id))
1468   {
1469     assert(space_id == PSParallelCompact::old_space_id,
1470            "cannot use FillClosure in the young gen");
1471   }
1472 
1473   virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
1474     CollectedHeap::fill_with_objects(addr, size);
1475     HeapWord* const end = addr + size;
1476     do {
1477       _start_array->allocate_block(addr);
1478       addr += oop(addr)->size();
1479     } while (addr < end);
1480     return ParMarkBitMap::incomplete;
1481   }
1482 
1483 private:
1484   ObjectStartArray* const _start_array;
1485 };
1486 
1487 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP