From: Nathan Scott <nathans@sgi.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Benjamin Rutt <rutt.4+news@osu.edu>, linux-kernel@vger.kernel.org
Subject: Re: clearing filesystem cache for I/O benchmarks
Date: Thu, 29 Jul 2004 11:05:46 +1000 [thread overview]
Message-ID: <20040729010546.GD800@frodo> (raw)
In-Reply-To: <20040726234005.597a94db.akpm@osdl.org>
On Mon, Jul 26, 2004 at 11:40:05PM -0700, Andrew Morton wrote:
> ...
> However... If you write any amount of data to a file with O_DIRECT, that
> will, as a side-effect, remove _all_ of that file's pagecache. In 2.4 as
> well as 2.6. So you could scrub the pagecache by reading the first 4k then
> writing it back with O_DIRECT.
>
> However O_DIRECT is supported on very few filesystems in 2.4. ext2 and
> reiserfs have it.
>
> XFS in 2.4 has O_DIRECT, I think, but I don't know if the invalidation
> side-effect works on XFS.
Yep, it does.
cheers.
--
Nathan
prev parent reply other threads:[~2004-07-29 0:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-23 22:54 clearing filesystem cache for I/O benchmarks Benjamin Rutt
2004-07-24 5:21 ` Chris Wedgwood
2004-07-24 5:31 ` Tim Wright
2004-07-26 0:07 ` Benjamin Rutt
2004-07-26 1:40 ` Bernd Eckenfels
2004-07-26 12:47 ` Benjamin Rutt
2004-07-25 8:11 ` Andreas Haumer
2004-07-26 7:25 ` Andrew Morton
2004-07-26 13:02 ` Benjamin Rutt
2004-07-27 6:40 ` Andrew Morton
2004-07-27 7:16 ` Hans Reiser
2004-07-27 17:31 ` Benjamin Rutt
2004-07-27 18:03 ` Hans Reiser
2004-07-28 12:38 ` Benjamin Rutt
2004-07-28 17:03 ` Hans Reiser
2004-07-28 18:19 ` Benjamin Rutt
2004-07-27 17:25 ` Benjamin Rutt
2004-07-27 20:00 ` Timothy Miller
2004-07-28 12:51 ` Benjamin Rutt
2004-07-29 1:05 ` Nathan Scott [this message]
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