From: Con Kolivas <kernel@kolivas.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, riel@redhat.com, david@fromorbit.com,
hch@lst.de, axboe@kernel.dk
Subject: Re: [PATCH] writeback: remove the internal 5% low bound on dirty_ratio
Date: Fri, 20 Aug 2010 15:50:54 +1000 [thread overview]
Message-ID: <201008201550.54164.kernel@kolivas.org> (raw)
In-Reply-To: <20100820131249.5FF4.A69D9226@jp.fujitsu.com>
On Fri, 20 Aug 2010 02:13:25 pm KOSAKI Motohiro wrote:
> > The dirty_ratio was silently limited to >= 5%. This is not a user
> > expected behavior. Let's rip it.
> >
> > It's not likely the user space will depend on the old behavior.
> > So the risk of breaking user space is very low.
> >
> > CC: Jan Kara <jack@suse.cz>
> > CC: Neil Brown <neilb@suse.de>
> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
>
> Thank you.
> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
I have tried to do this in the past, and setting this value to 0 on some
machines caused the machine to come to a complete standstill with small
writes to disk. It seemed there was some kind of "minimum" amount of data
required by the VM before anything would make it to the disk and I never
quite found out where that blockade occurred. This was some time ago (3 years
ago) so I'm not sure if the problem has since been fixed in the VM since
then. I suggest you do some testing with this value set to zero before
approving this change.
Regards,
--
-ck
next prev parent reply other threads:[~2010-08-20 5:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 3:25 [PATCH] writeback: remove the internal 5% low bound on dirty_ratio Wu Fengguang
2010-08-20 3:46 ` Rik van Riel
2010-08-20 4:13 ` KOSAKI Motohiro
2010-08-20 5:50 ` Con Kolivas [this message]
2010-08-20 5:56 ` Wu Fengguang
2010-08-23 4:42 ` Neil Brown
2010-08-23 6:23 ` Wu Fengguang
2010-08-23 6:30 ` Con Kolivas
2010-08-23 7:15 ` Wu Fengguang
2010-08-24 0:00 ` KOSAKI Motohiro
[not found] ` <201008241620.54048.kernel@kolivas.org>
[not found] ` <20100824071440.GA14598@localhost>
[not found] ` <201008251840.00532.kernel@kolivas.org>
2010-08-26 1:29 ` Wu Fengguang
2010-08-26 1:36 ` Neil Brown
2010-08-26 4:22 ` KOSAKI Motohiro
-- strict thread matches above, loose matches on Subject: below --
2010-08-27 10:36 Wu Fengguang
2010-08-27 10:39 ` Peter Zijlstra
2010-08-27 13:47 ` Rik van Riel
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