Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756992AbaKTOgh (ORCPT ); Thu, 20 Nov 2014 09:36:37 -0500 Received: from mail-wi0-f177.google.com ([209.85.212.177]:38829 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbaKTOgg (ORCPT ); Thu, 20 Nov 2014 09:36:36 -0500 Date: Thu, 20 Nov 2014 15:36:32 +0100 From: Frederic Weisbecker To: Dave Jones , Linus Torvalds , Don Zickus , Thomas Gleixner , Linux Kernel , the arch/x86 maintainers Subject: Re: frequent lockups in 3.18rc4 Message-ID: <20141120143626.GA2542@lerouge> References: <20141118020959.GA2091@redhat.com> <20141118023930.GA2871@redhat.com> <20141118145234.GA7487@redhat.com> <20141118215540.GD35311@redhat.com> <20141119021902.GA14216@redhat.com> <20141119051524.GA18547@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141119051524.GA18547@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 19, 2014 at 12:15:24AM -0500, Dave Jones wrote: > On Tue, Nov 18, 2014 at 08:40:55PM -0800, Linus Torvalds wrote: > > > Hmm, if we are getting soft-lockups here, maybe it suggest too much exit-work. > > > > Some TIF_NOHZ loop, perhaps? You have nohz on, don't you? > > > > That makes me wonder: does the problem go away if you disable NOHZ? > > Does nohz=off do enough ? I couldn't convince myself after looking at > dmesg, and still seeing dynticks stuff in there. > > I'll do a rebuild with all the CONFIG_NO_HZ stuff off, though it also changes > some other config stuff wrt timers. You also need to disable context tracking. So you need to deactive also CONFIG_RCU_USER_QS and CONFIG_CONTEXT_TRACKING_FORCE and eventually make sure nothing else is turning on CONFIG_CONTEXT_TRACKING. You can keep CONFIG_NO_HZ_IDLE though, just not CONFIG_NO_HZ_FULL. -- 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/