From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id B2CC46B02CA for ; Fri, 20 Aug 2010 01:56:29 -0400 (EDT) Date: Fri, 20 Aug 2010 13:56:21 +0800 From: Wu Fengguang Subject: Re: [PATCH] writeback: remove the internal 5% low bound on dirty_ratio Message-ID: <20100820055621.GA14110@localhost> References: <20100820032506.GA6662@localhost> <20100820131249.5FF4.A69D9226@jp.fujitsu.com> <201008201550.54164.kernel@kolivas.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201008201550.54164.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org To: Con Kolivas Cc: KOSAKI Motohiro , Andrew Morton , "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" List-ID: On Fri, Aug 20, 2010 at 01:50:54PM +0800, Con Kolivas wrote: > 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 > > > CC: Neil Brown > > > Signed-off-by: Wu Fengguang > > > > Thank you. > > Reviewed-by: KOSAKI Motohiro > > 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. Good point. I'll do more homework. Thanks for the reminding! Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org