Date: Thu, 29 Apr 2004 17:54:42 -0700
From: Paul Jackson <pj@sgi.com>
To: Andrew Morton <akpm@osdl.org>
Cc: adi@hexapodia.org, vonbrand@inf.utfsm.cl, nickpiggin@yahoo.com.au,
       jgarzik@pobox.com, brettspamacct@fastclick.com,
       linux-kernel@vger.kernel.org
Subject: Re: ~500 megs cached yet 2.6.5 goes into swap hell
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Andrew wrote:
> fadvise(POSIX_FADV_DONTNEED) is ideal for this.

Perhaps ... perhaps not.

Just as the knobs "only reclaim pagecache" and "reclaim vfs caches
harder" had too big a scope (system-wide), using fadvise might have too
small a scope (currently cached pages of current task only).

If his background daemon is some shell script, say, that uses 'cat' to
generate the i/o to the other spindle, then he probably wants to be
marking that daemon job "don't let this entire job eat my pagecache",
not rebuilding a hacked up cat command with added POSIX_FADV_DONTNEED
calls every megabyte.

CKRM to the rescue ... ??

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@sgi.com> 1.650.933.1373
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