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Date: Tue, 08 Oct 2002 13:03:11 -0700
From: Andrew Morton <akpm@digeo.com>
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To: Matthias Schniedermeyer <ms@citd.de>
CC: Chris Wedgwood <cw@f00f.org>, Robert Love <rml@tech9.net>,
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Subject: Re: [PATCH] O_STREAMING - flag for optimal streaming I/O
References: <1034044736.29463.318.camel@phantasy> <20021008183824.GA4494@tapu.f00f.org> <1034102950.30670.1433.camel@phantasy> <20021008190513.GA4728@tapu.f00f.org> <20021008195332.GA2313@citd.de>
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Matthias Schniedermeyer wrote:
> 
> ...
> I only have 3 GB of RAM, and creating and writing trashes the whole
> cache twice.

That's actually something completely dumb and irritating which
Linux has done for ever ;)

What we need is to detect the situation where someone is linearly
walking through a file which is preposterously too large to cache,
and just start dropping it.

It's not hard to implement the lower machinery to do that - it would
basically be an internal call to posix_fadvise(), which we don't
have but could and perhaps should...

The tricky part is designing the algorithm which decides when to
pull the trigger.
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