diff src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.hpp @ 187:790e66e5fbac

6687581: Make CMS work with compressed oops Summary: Make FreeChunk read markword instead of LSB in _klass pointer to indicate that it's a FreeChunk for compressed oops. Reviewed-by: ysr, jmasa
author coleenp
date Mon, 09 Jun 2008 11:51:19 -0400
parents a61af66fc99e
children d1605aabd0a1 12eea04c8b06
line wrap: on
line diff
--- a/src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.hpp	Fri Jun 06 11:47:26 2008 -0700
+++ b/src/share/vm/gc_implementation/concurrentMarkSweep/freeBlockDictionary.hpp	Mon Jun 09 11:51:19 2008 -0400
@@ -22,88 +22,6 @@
  *
  */
 
-//
-// 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.