From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752837AbcHQPse (ORCPT ); Wed, 17 Aug 2016 11:48:34 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36153 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752255AbcHQPsb (ORCPT ); Wed, 17 Aug 2016 11:48:31 -0400 Date: Wed, 17 Aug 2016 17:48:26 +0200 From: Michal Hocko To: Linus Torvalds Cc: Mel Gorman , Minchan Kim , Vladimir Davydov , Dave Chinner , Johannes Weiner , Vlastimil Babka , Andrew Morton , Bob Peterson , "Kirill A. Shutemov" , "Huang, Ying" , Christoph Hellwig , Wu Fengguang , LKP , Tejun Heo , LKML Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Message-ID: <20160817154825.GC20719@dhcp22.suse.cz> References: <20160815050016.GY19025@dastard> <20160815222211.GA19025@dastard> <20160815224259.GB19025@dastard> <20160816150500.GH8119@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 16-08-16 10:47:36, Linus Torvalds wrote: > Mel, > thanks for taking a look. Your theory sounds more complete than mine, > and since Dave is able to see the problem with 4.7, it would be nice > to hear about the 4.6 behavior and commit ede37713737 in particular. > > That one seems more likely to affect contention than the zone/node one > I found during the merge window anyway, since it actually removes a > sleep in kswapd during congestion. Hmm, the patch removes a short sleep from wait_iff_congested for kworkers but that cannot affect kswapd context. Then it removes wait_iff_congested from should_reclaim_retry but that is not kswapd path and the sleep was added in the same merge window so it wasn't in 4.6 so it shouldn't make any difference as well. So I am not really sure how it could make any difference. I will try to catch up with the rest of the email thread but from a quick glance it just feels like we are doing more more work under the lock. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============1264752532010870314==" MIME-Version: 1.0 From: Michal Hocko To: lkp@lists.01.org Subject: Re: [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression Date: Wed, 17 Aug 2016 17:48:26 +0200 Message-ID: <20160817154825.GC20719@dhcp22.suse.cz> In-Reply-To: List-Id: --===============1264752532010870314== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Tue 16-08-16 10:47:36, Linus Torvalds wrote: > Mel, > thanks for taking a look. Your theory sounds more complete than mine, > and since Dave is able to see the problem with 4.7, it would be nice > to hear about the 4.6 behavior and commit ede37713737 in particular. > = > That one seems more likely to affect contention than the zone/node one > I found during the merge window anyway, since it actually removes a > sleep in kswapd during congestion. Hmm, the patch removes a short sleep from wait_iff_congested for kworkers but that cannot affect kswapd context. Then it removes wait_iff_congested from should_reclaim_retry but that is not kswapd path and the sleep was added in the same merge window so it wasn't in 4.6 so it shouldn't make any difference as well. So I am not really sure how it could make any difference. I will try to catch up with the rest of the email thread but from a quick glance it just feels like we are doing more more work under the lock. -- = Michal Hocko SUSE Labs --===============1264752532010870314==--