From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joao Correia Subject: Re: Soft-Lockup/Race in networking in 2.6.31-rc1+195 ( possibly?caused by netem) Date: Tue, 7 Jul 2009 11:40:16 +0100 Message-ID: References: <200907031326.21822.andres@anarazel.de> <20090706163106.GA4559@ami.dom.local> <200907061926.43625.andres@anarazel.de> <20090707065014.GA3296@ami.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Arun R Bharadwaj , Thomas Gleixner , Stephen Hemminger , netdev@vger.kernel.org, LKML , Andres Freund To: Jarek Poplawski Return-path: Received: from mail-fx0-f218.google.com ([209.85.220.218]:51991 "EHLO mail-fx0-f218.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753159AbZGGKke convert rfc822-to-8bit (ORCPT ); Tue, 7 Jul 2009 06:40:34 -0400 In-Reply-To: <20090707065014.GA3296@ami.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: I am now running 2.6.31-rc2 for a couple of hours, no freeze. Let me know what/if i can help with tracking down the original source of the problem. Thank you very much for your time, Joao Correia On Tue, Jul 7, 2009 at 7:50 AM, Jarek Poplawski wrot= e: > On Mon, Jul 06, 2009 at 07:26:43PM +0200, Andres Freund wrote: >> On Monday 06 July 2009 19:23:18 Joao Correia wrote: >> > Hello >> > >> > Since i already had the kernel compiled and ready to boot when i r= ead >> > this, i gave it a go anyway :-). >> > >> > I can reproduce the freeze with those 4 patches applied, so i can >> > confirm that its, at least, related to, or exposed by, those patch= es. >> > There must be something else too, or its just too much fuzziness, = but >> > the freeze takes a bit more time (approximately five minutes, give= or >> > take) compared to the instant freeze before, but its there with th= e >> > patches, and without them, no freeze. >> > >> > I assume there isnt a "safe" way to get them out of current .31-rc= 's, >> > right? >> `echo 0 > /proc/sys/kernel/timer_migration` should mitigate the prob= lem. > > I guess it should fix it entirely. Btw., here is a patch disabling th= e > timers' part, so to make it hrtimers only. Could you try? > > Thanks, > Jarek P. > --- > > diff --git a/kernel/timer.c b/kernel/timer.c > index 0b36b9e..011429c 100644 > --- a/kernel/timer.c > +++ b/kernel/timer.c > @@ -634,7 +634,7 @@ __mod_timer(struct timer_list *timer, unsigned lo= ng expires, > > =A0 =A0 =A0 =A0cpu =3D smp_processor_id(); > > -#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP) > +#if 0 > =A0 =A0 =A0 =A0if (!pinned && get_sysctl_timer_migration() && idle_cp= u(cpu)) { > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0int preferred_cpu =3D get_nohz_load_ba= lancer(); > >