From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH 0/4] writeback: tracing and wbc->nr_to_write fixes Date: Wed, 21 Apr 2010 09:29:04 +1000 Message-ID: <20100420232904.GA23541@dastard> References: <1271731314-5893-1-git-send-email-david@fromorbit.com> <4BCD97C8.6090406@rsk.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com To: Richard Kennedy Return-path: Content-Disposition: inline In-Reply-To: <4BCD97C8.6090406@rsk.demon.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Apr 20, 2010 at 01:02:16PM +0100, Richard Kennedy wrote: > On 20/04/10 03:41, Dave Chinner wrote: > > This series contains the initial writeback tracing patches from > > Jens, as well as the extensions I added to provide visibility into > > writeback control structures as the are used by the writeback code. > > The visibility given is sufficient to understand what is happening > > in the writeback path - what path is writing data, what path is > > blocking on congestion, etc, and to determine the differences in > > behaviour for different sync modes and calling contexts. This > > tracing really needs to be integrated into mainline so that anyone > > can improve the tracing as they use it to track down problems > > in our convoluted writeback paths. > > > > The remaining patches are fixes to problems that the new tracing > > highlighted. > > Hi Dave, > > Thanks for adding tracing to this, it will be really useful. > > The fix to write_cache_pages looks really interesting, I'm going to test > it on my machine. Maybe it should be a separate patch to get more > visibility? I don't see a big need to separate the series at this point. Once there's been a review and testing we can decide how to push them into mainline. IMO, the tracing is just as important as the bug fixes.... > Ext4 also multiplies nr_to_write, so will that need fixing too? No idea. I don't claim to understand ext4's convoluted delayed allocation path and all it's constraints, so I guess you'd need to ask the ext4 developers about that one. After all, with the tracing they'd be able to see if there is a problem. ;) Cheers, Dave. -- Dave Chinner david@fromorbit.com