From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752958Ab1GGT7O (ORCPT ); Thu, 7 Jul 2011 15:59:14 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:45987 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752818Ab1GGT7K (ORCPT ); Thu, 7 Jul 2011 15:59:10 -0400 Date: Thu, 7 Jul 2011 12:58:45 -0700 From: "Paul E. McKenney" To: julie Sullivan Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org, torvalds@linux-foundation.org Subject: Re: PROBLEM: 3.0-rc kernels unbootable since -rc3 Message-ID: <20110707195845.GD6014@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20110706212348.GO6014@linux.vnet.ibm.com> <201107072047.14429.kernelmail.jms@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201107072047.14429.kernelmail.jms@gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 07, 2011 at 08:47:13PM +0100, julie Sullivan wrote: > On Wednesday 06 July 2011 22:23:48 Paul E. McKenney wrote: > > On Wed, Jul 06, 2011 at 10:10:16PM +0100, julie Sullivan wrote: > > > None of my kernels after 3.0-rc3 will boot on my Dell XPS-M1730 > > > (x86-64 2-core) test box running > > > Ubuntu (Kubuntu) 11.04 (i.e. the first unbootable one was -rc4). > > > The machine freezes immediately after selecting the kernel from the > > > bootloader menu, leaving > > > me with a blank blue screen so I can't give you any log messages. > > > > > > It bisects to the following commit: > > > > > > commit a46e0899eec7a3069bcadd45dfba7bf67c6ed016 > > > Author: Paul E. McKenney > > > Date: Wed Jun 15 15:47:09 2011 -0700 > > > > > > rcu: use softirq instead of kthreads except when RCU_BOOST=y > > > > > > This patch #ifdefs RCU kthreads out of the kernel unless RCU_BOOST=y, > > > thus eliminating context-switch overhead if RCU priority boosting has > > > not been configured. > > > > > > Signed-off-by: Paul E. McKenney > > > > > Hello, Julie, > > > > One approach would be to cherry-pick the following commits: > > > > f8b7fc6b514f34a51875dd48dff70d4d17a54f38 rcu: Move RCU_BOOST #ifdefs to header f > > a46e0899eec7a3069bcadd45dfba7bf67c6ed016 rcu: use softirq instead of kthreads ex > > 09223371deac67d08ca0b70bd18787920284c967 rcu: Use softirq to address performance > > 9a432736904d386cda28b987b38ba14dae960ecc rcu: Simplify curing of load woes > > > > > Another approach would be to move ahead to v3.0-rc4 or later. > > > > Thanx, Paul > > Hi Paul > Thanks for your prompt reply, sorry for the delay in mine (real life intervened :-) > I tried reverting those 4 commits on v3.0-rc4 and can confirm that it _does_ give me a bootable 3.0-rc4 kernel. > I'll do some more testing. If you would like me to try anything specific just let me know :-) What happens if you revert only these two? f8b7fc6b514f34a51875dd48dff70d4d17a54f38 rcu: Move RCU_BOOST #ifdefs to header f a46e0899eec7a3069bcadd45dfba7bf67c6ed016 rcu: use softirq instead of kthreads ex If that works, perhaps we should try to break down a46e0899ee into smaller pieces to see what is causing the trouble. Thanx, Paul