Subject: Re: Machine-independent bus DMA interface proposal
To: John Kohl <>
From: Curt Sampson <>
List: tech-kern
Date: 09/24/1996 16:56:27
On Tue, 24 Sep 1996, John Kohl wrote:

> This cost can be greatly amortized with certain allocation strategies,
> such as the slab allocator described by someone from Sun at the Winter
> 1995 USENIX.  Basically, you take a chunk/page/whatever of memory from
> the normal kernel allocator and pre-initialize it for fixed-size
> allocations specific to a memory type, using simple free list management
> within this slab.

I believe that the 4.4BSD kernel memory allocator already does more
or less just this. According to the 4.4BSD book (p. 129), for
allocations smaller than the page size a page is divided up into
chunks of size 2^n bytes, and these are parcelled off to programs
that request a chunk between 2^(n-1) and 2^n bytes large.


Curt Sampson		Info at
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