From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: [PATCH] fs-writeback: drop wb->list_lock during blk_finish_plug() Date: Sat, 12 Sep 2015 19:46:32 -0400 Message-ID: <20150912234632.GF4150@ret.masoncoding.com> References: <20150911193747.GA4150@ret.masoncoding.com> <55F33C2B.1010508@fb.com> <20150911231636.GC4150@ret.masoncoding.com> <20150912230027.GE4150@ret.masoncoding.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Josef Bacik , LKML , linux-fsdevel , Dave Chinner , Neil Brown , Jan Kara , Christoph Hellwig To: Linus Torvalds Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:38995 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752356AbbILXqo (ORCPT ); Sat, 12 Sep 2015 19:46:44 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Sat, Sep 12, 2015 at 04:29:06PM -0700, Linus Torvalds wrote: > On Sat, Sep 12, 2015 at 4:00 PM, Chris Mason wrote: > > > > I did the plain revert as well, just to have a baseline. > > Ahh, I ended up not expecting you to get this done until after rc1 was > out, so I in the meantime just merged my fix instead rather than leave > the expected scheduling-while-atomic problem. Yeah, I wasn't sure I'd be able to do the runs, but it was a rainy afternoon and this was more fun than cleaning. Really glad something got in for rc1 either way. > > And just as well that you did a baseline, since apparently the numbers > are all over the map. I don't see how your hack and dave's original > can _possibly_ differ that much, but they clearly did on your xfs > test. So there's probably huge variance that depends on random > details. I don't think the XFS numbers can be trusted too much since it was basically bottlenecked behind that single pegged CPU. It was bouncing around and I couldn't quite track it down to a process name (or perf profile). The btrfs numbers were much more consistent, but your patch is still a win over plain 4.2. > > I'll leave things as they are until we have something that looks a bit > more believable ;) We can build from here, thanks Linus. -chris