hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.hpp

rev 611 : Merge

*** 1,10 ****
  #ifdef USE_PRAGMA_IDENT_HDR
  #pragma ident "@(#)freeBlockDictionary.hpp      1.32 07/05/05 17:05:47 JVM"
  #endif
  /*
!  * Copyright 2001-2005 Sun Microsystems, Inc.  All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
--- 1,10 ----
  #ifdef USE_PRAGMA_IDENT_HDR
  #pragma ident "@(#)freeBlockDictionary.hpp      1.32 07/05/05 17:05:47 JVM"
  #endif
  /*
!  * Copyright 2001-2008 Sun Microsystems, Inc.  All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 23,115 ****
   * CA 95054 USA or visit www.sun.com if you need additional information or
   * have any questions.
   *  
   */
  
- //
- // Free block maintenance for Concurrent Mark Sweep Generation
- //
- // The main data structure for free blocks are
- // . an indexed array of small free blocks, and
- // . a dictionary of large free blocks
- //
- 
- // No virtuals in FreeChunk (don't want any vtables).
- 
- // A FreeChunk is merely a chunk that can be in a doubly linked list
- // and has a size field. NOTE: FreeChunks are distinguished from allocated
- // objects in two ways (by the sweeper). The second word (prev) has the
- // LSB set to indicate a free chunk; allocated objects' klass() pointers
- // don't have their LSB set. The corresponding bit in the CMSBitMap is
- // set when the chunk is allocated. There are also blocks that "look free"
- // but are not part of the free list and should not be coalesced into larger
- // free blocks. These free blocks have their two LSB's set.
- 
- class FreeChunk VALUE_OBJ_CLASS_SPEC {
-   friend class VMStructs;
-   FreeChunk* _next;
-   FreeChunk* _prev;
-   size_t     _size;
- 
-  public:
-   NOT_PRODUCT(static const size_t header_size();)
-   // Returns "true" if the "wrd", which is required to be the second word
-   // of a block, indicates that the block represents a free chunk.
-   static bool secondWordIndicatesFreeChunk(intptr_t wrd) {
-     return (wrd & 0x1) == 0x1;
-   }
-   bool isFree()       const {
-     return secondWordIndicatesFreeChunk((intptr_t)_prev);
-   }
-   bool cantCoalesce() const { return (((intptr_t)_prev) & 0x3) == 0x3; }
-   FreeChunk* next()   const { return _next; }
-   FreeChunk* prev()   const { return (FreeChunk*)(((intptr_t)_prev) & ~(0x3)); }
-   debug_only(void* prev_addr() const { return (void*)&_prev; })
- 
-   void linkAfter(FreeChunk* ptr) {
-     linkNext(ptr);
-     if (ptr != NULL) ptr->linkPrev(this);
-   }
-   void linkAfterNonNull(FreeChunk* ptr) {
-     assert(ptr != NULL, "precondition violation");
-     linkNext(ptr);
-     ptr->linkPrev(this);
-   }
-   void linkNext(FreeChunk* ptr) { _next = ptr; }
-   void linkPrev(FreeChunk* ptr) { _prev = (FreeChunk*)((intptr_t)ptr | 0x1); }
-   void clearPrev()              { _prev = NULL; }
-   void clearNext()              { _next = NULL; }
-   void dontCoalesce()      {
-     // the block should be free
-     assert(isFree(), "Should look like a free block");
-     _prev = (FreeChunk*)(((intptr_t)_prev) | 0x2);
-   }
-   void markFree()    { _prev = (FreeChunk*)((intptr_t)_prev | 0x1);    }
-   void markNotFree() { _prev = NULL; }
- 
-   size_t size()           const { return _size; }
-   void setSize(size_t size)     { _size = size; }
- 
-   // For volatile reads:
-   size_t* size_addr()           { return &_size; }
- 
-   // Return the address past the end of this chunk
-   HeapWord* end() const { return ((HeapWord*) this) + _size; }
- 
-   // debugging
-   void verify()             const PRODUCT_RETURN;
-   void verifyList()         const PRODUCT_RETURN;
-   void mangleAllocated(size_t size) PRODUCT_RETURN;
-   void mangleFreed(size_t size)     PRODUCT_RETURN; 
- };
- 
- // Alignment helpers etc.
- #define numQuanta(x,y) ((x+y-1)/y)
- enum AlignmentConstants {
-   MinChunkSize = numQuanta(sizeof(FreeChunk), MinObjAlignmentInBytes) * MinObjAlignment
- };
- 
  // A FreeBlockDictionary is an abstract superclass that will allow
  // a number of alternative implementations in the future.
  class FreeBlockDictionary: public CHeapObj {
   public:
    enum Dither {
--- 23,32 ----