* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.52 2003/08/04 02:40:08 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.53 2003/09/13 22:25:38 tgl Exp $
*
* NOTE:
* This is a new (Feb. 05, 1999) implementation of the allocation set
}
else
{
- /* Get size of prior block */
- blksize = set->blocks->endptr - ((char *) set->blocks);
-
/*
- * Special case: if very first allocation was for a large
- * chunk (or we have a small "keeper" block), could have an
- * undersized top block. Do something reasonable.
+ * Use first power of 2 that is larger than previous block,
+ * but not more than the allowed limit. (We don't simply double
+ * the prior block size, because in some cases this could be a
+ * funny size, eg if very first allocation was for an odd-sized
+ * large chunk.)
*/
- if (blksize < set->initBlockSize)
- blksize = set->initBlockSize;
- else
- {
- /* Crank it up, but not past max */
+ Size pblksize = set->blocks->endptr - ((char *) set->blocks);
+
+ blksize = set->initBlockSize;
+ while (blksize <= pblksize)
blksize <<= 1;
- if (blksize > set->maxBlockSize)
- blksize = set->maxBlockSize;
- }
+ if (blksize > set->maxBlockSize)
+ blksize = set->maxBlockSize;
}
/*
* If initBlockSize is less than ALLOC_CHUNK_LIMIT, we could need
- * more space...
+ * more space... but try to keep it a power of 2.
*/
required_size = chunk_size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
- if (blksize < required_size)
- blksize = required_size;
+ while (blksize < required_size)
+ blksize <<= 1;
/* Try to allocate it */
block = (AllocBlock) malloc(blksize);