Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751747Ab3IQADF (ORCPT ); Mon, 16 Sep 2013 20:03:05 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:55180 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751204Ab3IQADA (ORCPT ); Mon, 16 Sep 2013 20:03:00 -0400 Date: Mon, 16 Sep 2013 20:02:44 -0400 From: Johannes Weiner To: azurIt Cc: Michal Hocko , Andrew Morton , David Rientjes , KAMEZAWA Hiroyuki , KOSAKI Motohiro , linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch 0/7] improve memcg oom killer robustness v2 Message-ID: <20130917000244.GD3278@cmpxchg.org> References: <20130911200426.GO856@cmpxchg.org> <20130914124831.4DD20346@pobox.sk> <20130916134014.GA3674@dhcp22.suse.cz> <20130916160119.2E76C2A1@pobox.sk> <20130916140607.GC3674@dhcp22.suse.cz> <20130916161316.5113F6E7@pobox.sk> <20130916145744.GE3674@dhcp22.suse.cz> <20130916170543.77F1ECB4@pobox.sk> <20130916152548.GF3674@dhcp22.suse.cz> <20130916225246.A633145B@pobox.sk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130916225246.A633145B@pobox.sk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2781 Lines: 48 On Mon, Sep 16, 2013 at 10:52:46PM +0200, azurIt wrote: > > CC: "Johannes Weiner" , "Andrew Morton" , "David Rientjes" , "KAMEZAWA Hiroyuki" , "KOSAKI Motohiro" , linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org > >On Mon 16-09-13 17:05:43, azurIt wrote: > >> > CC: "Johannes Weiner" , "Andrew Morton" , "David Rientjes" , "KAMEZAWA Hiroyuki" , "KOSAKI Motohiro" , linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org > >> >On Mon 16-09-13 16:13:16, azurIt wrote: > >> >[...] > >> >> >You can use sysrq+l via serial console to see tasks hogging the CPU or > >> >> >sysrq+t to see all the existing tasks. > >> >> > >> >> > >> >> Doesn't work here, it just prints 'l' resp. 't'. > >> > > >> >I am using telnet for accessing my serial consoles exported by > >> >the multiplicator or KVM and it can send sysrq via ctrl+t (Send > >> >Break). Check your serial console setup. > >> > >> > >> > >> I'm using Raritan KVM and i created keyboard macro 'sysrq + l' resp. > >> 'sysrq + t'. I'm also unable to use it on my local PC. Maybe it needs > >> to be enabled somehow? > > > >Probably yes. echo 1 > /proc/sys/kernel/sysrq should enable all sysrq > >commands. You can select also some of them (have a look at > >Documentation/sysrq.txt for more information) > > > Now it happens again and i was just looking on the server's > htop. I'm sure that this time it was only one process (apache) > running under user account (not root). It was taking about 100% CPU > (about 100% of one core). I was able to kill it by hand inside htop > but everything was very slow, server load was immediately on > 500. I'm sure it must be related to that Johannes kernel patches > because i'm also using i/o throttling in cgroups via Block IO > controller so users are unable to create such a huge I/O. I will try > to take stacks of processes but i'm not able to identify the > problematic process so i will have to take them from *all* apache > processes while killing them. It would be fantastic if you could capture those stacks. sysrq+t captures ALL of them in one go and drops them into your syslog. /proc//stack for individual tasks works too. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/