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Date: Mon, 30 Jun 1997 19:52:35 -0700
From: Julian Elischer <julian@whistle.com>
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To: Jason Thorpe <thorpej@nas.nasa.gov>
CC: Vivek Sadananda Pai <vivek@cs.rice.edu>, freebsd-hackers@freebsd.org
Subject: Re: mbuf external storage
References: <199707010215.TAA27715@lestat.nas.nasa.gov>
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Jason Thorpe wrote:
> 

> I also recommend taking a look at the external storage mbuf code in
> NetBSD that was done by Matt Thomas and myself.  NetBSD actively uses
> it in the handling of UNIX domain sockets, and I'm experimenting using
> it for DMA buffer loan-out for high performance network interfaces
> (such as Myrinet and Hippi); doing this really effectively is going
> to require an additional function call interface to deal with the
> transmit case, however... that's to-be-attacked later.

I agrree that the OSF idea has merrit.
it's also possible to make a hybrid scheme that allows 
even more flexibility.
(I had code for that somewhere..)



>  > > there's some reason why it was removed?
>  > It was never there.
>  > It might be useful to include it.. I just overload the 'ext_size'
>  > argument. (as nothing uses it).
> 
> That's seriously bogus... ext_size _is_ used in e.g. NetBSD's NFS code,
> and when you think about running on 64-bit architectures (like the
> Alpha, which FreeBSD has ambitions about running on), then you can't
> resort to such a kludge.
> 
> Jason

I agree and it was a temporary 'kludge'.
in special purpose code that will get rewritten eventually.