From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: REGRESSION: 3.10-rc1: Dell Latitude e6410 hangs within 3 seconds Date: Fri, 17 May 2013 18:47:25 -0700 Message-ID: <20130518014724.GA4006@linux.vnet.ibm.com> References: <5192363E.7040204@broadcom.com> <1396357.SFbZsj3Bmy@vostro.rjw.lan> <5192A0DE.90209@broadcom.com> <519697CC.1070308@broadcom.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:37553 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753985Ab3ERBr3 (ORCPT ); Fri, 17 May 2013 21:47:29 -0400 Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 17 May 2013 19:47:29 -0600 Content-Disposition: inline In-Reply-To: <519697CC.1070308@broadcom.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Arend van Spriel Cc: "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , ACPI Devel Maling List , "Paul E. McKenney" On Fri, May 17, 2013 at 10:49:16PM +0200, Arend van Spriel wrote: > On 05/14/2013 10:38 PM, Arend van Spriel wrote: > >On 05/14/2013 10:34 PM, Rafael J. Wysocki wrote: > >>On Tuesday, May 14, 2013 03:03:58 PM Arend van Spriel wrote: > >>>Laptop hangs pretty soon after booting. Workaround for me was to t= urn > >>>off ACPI on kernel command line, ie. acpi=3Doff > >>> > >>>Attached is my kernel configuration. > >> > >>Well, I have no idea what may be the source of this. > > > >Me neither. > > > >>Any chance to bisect? > > > >can try. Rebuilding kernels can be a drag :-p > > > >Regards, > >Arend >=20 > Hi Rafael, >=20 > The bisect result found commit c0f4dfd4f as culprit. I also verified > that the merge into Linus' tree introduced the issue upstream, ie. > 6c24499 works and 1f889ec does not. I tried to revert the commit, > but that was a bit risky (conflict to resolve) and did not give me a > stable kernel. The only thing that works is selecting acpi=3Doff. I > tried also nohz=3Doff but that resulted in /init failure. >=20 > Regards, > Arend >=20 > ---8<---------------------------------------------------------------- >=20 > commit 1f889ec62c3f0d8913f3c32f9aff2a1e15099346 > Merge: 6c24499 8fcfae3 >=20 > commit 8fcfae31719c0a6c03f2cf63f815b46d378d8be4 > Merge: d02a9a8 6d87669 >=20 > commit 6d87669357936bffa1e8fea7a4e7743e76905736 > Merge: 3f944ad 81e5949 910ee45 >=20 > commit c0f4dfd4f90f1667d234d21f15153ea09a2eaa66 > Author: Paul E. McKenney > Date: Fri Dec 28 11:30:36 2012 -0800 >=20 > rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbac= ks >=20 > Because RCU callbacks are now associated with the number > of the grace period that they must wait for, CPUs can now > take advance callbacks corresponding to grace periods that > ended while a given CPU was in dyntick-idle mode. This > eliminates the need to try forcing the RCU state machine > while entering idle, thus reducing the CPU intensiveness > of RCU_FAST_NO_HZ, which should increase its energy > efficiency. >=20 > Signed-off-by: Paul E. McKenney > Signed-off-by: Paul E. McKenney Hello, Arend, Thank you for tracking this down! Could you please try out the followi= ng patch? Thanx, Paul -----------------------------------------------------------------------= - rcu: Fix comparison sense in rcu_needs_cpu() Commit c0f4dfd4f (rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks) introduced a bug that can result in excessively long grace periods. This bug reverse the senes of the "if" statement checking for lazy callbacks, so that RCU takes a lazy approach when there are in fact non-lazy callbacks. This can result in excessive boot, suspend= , and resume times. This commit therefore fixes the sense of this "if" statement. Reported-by: Borislav Petkov Reported-by: Bj=F8rn Mork Reported-by: Joerg Roedel Signed-off-by: Paul E. McKenney Tested-by: Bj=F8rn Mork Tested-by: Joerg Roedel diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 170814d..6d939a6 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1667,7 +1667,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj) rdtp->last_accelerate =3D jiffies; =20 /* Request timer delay depending on laziness, and round. */ - if (rdtp->all_lazy) { + if (!rdtp->all_lazy) { *dj =3D round_up(rcu_idle_gp_delay + jiffies, rcu_idle_gp_delay) - jiffies; } else { -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html