Message-ID: <3F672A9A.9060809@techsource.com>
Date: Tue, 16 Sep 2003 11:22:02 -0400
From: Timothy Miller <miller@techsource.com>
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To: Stephan von Krawczynski <skraw@ithnet.com>
CC: Marcelo Tosatti <marcelo.tosatti@cyclades.com.br>, neilb@cse.unsw.edu.au,
       linux-kernel@vger.kernel.org
Subject: Re: experiences beyond 4 GB RAM with 2.4.22
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Stephan von Krawczynski wrote:
> On Tue, 16 Sep 2003 10:11:49 -0300 (BRT)
> Marcelo Tosatti <marcelo.tosatti@cyclades.com.br> wrote:
> 
> 
>>Oh... Jens just pointed bounce buffering is needed for the upper 2Gs. 
>>
>>Maybe you have a SCSI card+disks to test ? 8)
> 
> 
> 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?
> We should not leave the current bad situation as is...

If there were some kind of tracking to determine which processes are 
doing I/O which requires the process to be in low memory.  Then, 
processes can be migrated around in physical memory so as to optimize 
for that.

Or is that already being done?

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