Subject: Re: experiences beyond 4 GB RAM with 2.4.22
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Stephan von Krawczynski <skraw@ithnet.com>
Cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com.br>, neilb@cse.unsw.edu.au,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Maw, 2003-09-16 at 14:36, Stephan von Krawczynski wrote:
> Well, I do understand the bounce buffer problem, but honestly the current way
> of handling the situation seems questionable at least. If you ever tried such a
> system you notice it is a lot worse than just dumping the additional ram above
> 4GB. You can really watch your network connections go bogus which is just
> unacceptable. Is there any thinkable way to ommit the bounce buffers and still
> do something useful with the beyond-4GB ram parts?

The 2.6 tree is somewhat better about this but at the end of the day if
your I/O subsystem can't do the job your box will not perform ideally.
For some workloads its a huge win to have the extra RAM, for others the
I/O is a real pain. Also in some cases it might be interesting to try
using the extra RAM above the 4G boundary as a giant ram disk and using
it as first swap device.

I don't know anyone who explored that however


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