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From: Tim Kientzle <tim@kientzle.com>
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Date: Tue, 8 Nov 2011 20:11:35 -0800
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To: Alfred Perlstein <alfred@freebsd.org>
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Cc: Bruce Cran <bruce@cran.org.uk>, Ed Schouten <ed@80386.nl>,
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Subject: Re: [PATCH] fadvise(2) system call
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On Nov 8, 2011, at 7:35 PM, Alfred Perlstein wrote:
> 
> One other optimization would be to set the bit when tar or other such apps
> notice that the file exceeds the memory of the system, effectively noting
> that it would be blowing out the entire cache.

Tar does not know the amount of RAM in the system
nor the size of the cache.  It definitely does not know
how the kernel caching policies interact with any particular
access pattern.

It should be able to provide hints to the kernel
about the likely access pattern, though.

Tim