From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ipmailnode02.adl6.internode.on.net ([150.101.137.148]:3919 "EHLO ipmailnode02.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726101AbfBKBzn (ORCPT ); Sun, 10 Feb 2019 20:55:43 -0500 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1gt0ou-0000wi-Gk for fstests@vger.kernel.org; Mon, 11 Feb 2019 12:55:40 +1100 Date: Mon, 11 Feb 2019 12:55:40 +1100 From: Dave Chinner Subject: Re: [PATCH] xfs: new EOF fragmentation tests Message-ID: <20190211015540.GD20493@dastard> References: <20190211013647.22580-1-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211013647.22580-1-david@fromorbit.com> Sender: fstests-owner@vger.kernel.org To: fstests@vger.kernel.org List-ID: On Mon, Feb 11, 2019 at 12:36:47PM +1100, Dave Chinner wrote: > From: Dave Chinner > > These tests create substantial file fragmentation as a result of > application actions that defeat post-EOF preallocation > optimisations. They are intended to replicate known vectors for > these problems, and provide a check that the fragmentation levels > have been controlled. The mitigations we make may not completely > remove fragmentation (e.g. they may demonstrate speculative delalloc > related extent size growth) so the checks don't assume we'll end up > with perfect layouts and hence check for an exceptable level of > fragmentation rather than none. > > Signed-off-by: Dave Chinner > --- Forgot to add that these tests go along with this patch series: https://marc.info/?l=linux-xfs&m=154951612101291&w=2 And can be used to test whatever way we decide to minimise fragmentation through maintianing post-EOF preallocation. Cheers, Dave. -- Dave Chinner david@fromorbit.com