From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mikael Pettersson Subject: Re: [3.13 regression] kswapd0 and ksoftirqd/0 CPU hogs Date: Sun, 6 Mar 2016 08:21:34 +0100 Message-ID: <22235.55934.43914.623042@gargle.gargle.HOWL> References: <21393.43065.207399.530921@gargle.gargle.HOWL> <21426.40682.197715.245775@gargle.gargle.HOWL> <21786.40688.53001.509365@gargle.gargle.HOWL> <22217.61083.254294.356622@gargle.gargle.HOWL> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f172.google.com ([209.85.217.172]:35955 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbcCFHVi (ORCPT ); Sun, 6 Mar 2016 02:21:38 -0500 Received: by mail-lb0-f172.google.com with SMTP id x1so100630438lbj.3 for ; Sat, 05 Mar 2016 23:21:37 -0800 (PST) In-Reply-To: Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Geert Uytterhoeven Cc: Mikael Pettersson , Michael Schmitz , Andreas Schwab , Linux/m68k Geert Uytterhoeven writes: > Hi Mikael, > > On Sun, Feb 21, 2016 at 6:06 PM, Mikael Pettersson wrote: > > Mikael Pettersson writes: > > > Michael Schmitz writes: > > > > has anyone found a solution to this one? > > > > > > > > 3.18-rc5 has kswapd0 hogging the CPU - haven't seen ksoftirqd0 yet. > > > > Unpacking a large tarball tends to trigger this for me. > > > > > > Alas, no. I went back to the 3.10.xx kernels and they work Ok for me > > > (they tend to hang during shutdown, but I can live with that). > > > > > > I should do a git bisect... > > > > I've done two git bisects on this. The first one was inconclusive > > (pointed to a harmless commit), but the second one ended up with: > > Thanks a lot for doing this! > > > # first bad commit: [ac4de9543aca59f2b763746647577302fbedd57e] Merge branch 'akpm' (patches from Andrew Morton) > > > > That's a big pile of VM changes, so I think it could be the culprit. > > So git bisect pointed to the merge commit itself, not to any of the commits in > the akpm branch? > > I redid that merge myself, and the result is the same as ac4de9543aca5. > There could still be a semantical merge conflict that cannot be detected by > git, though. > > Could you try cherry-picking the 36 commits from the akpm branch and > bisecting that? > I.e. > git checkout 26935fb06ee88f11 > git cherry-pick 26935fb06ee88f11..de32a8177f64bc62 > git bisect start > git bisect bad > git bisect good 26935fb06ee88f11 I ran these exact commands and restarted my bisection + test loop. However, git told me it had some 50000+ commits to go through in 16 steps, so it looks like it selected a much larger range than those 36 commits. /Mikael