From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757832Ab1EKQ4k (ORCPT ); Wed, 11 May 2011 12:56:40 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:55839 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756037Ab1EKQ4g convert rfc822-to-8bit (ORCPT ); Wed, 11 May 2011 12:56:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=OO0PejAnniemhkWXwrRRSU4iPz67kaBbR0bMHPvJESR5SYpM5AnJHVu2NPKW8j2+SE 3XoT5/Lyw6ZvwBmOXKOtpjlfPb8LrbnApGH42AlcDREBU5lBpdJDAu44GMHrGEAYBp/W qyot1eyRaYEBPNb3fWpLakaBcr26QO+KAjPTg= MIME-Version: 1.0 In-Reply-To: <20110511045443.GS2258@linux.vnet.ibm.com> References: <20110508151848.GA21906@linux.vnet.ibm.com> <20110509073636.GA18247@elte.hu> <20110510085623.GG2258@linux.vnet.ibm.com> <4DC97E49.7040401@kernel.org> <20110510193216.GN2258@linux.vnet.ibm.com> <4DC9A5A4.1050308@kernel.org> <20110511045443.GS2258@linux.vnet.ibm.com> Date: Wed, 11 May 2011 09:56:35 -0700 X-Google-Sender-Auth: ERPtIhpvdN0da0M4KN0Oe5B5ab4 Message-ID: Subject: Re: [GIT PULL rcu/next] rcu commits for 2.6.40 From: Yinghai Lu To: paulmck@linux.vnet.ibm.com Cc: Ingo Molnar , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 10, 2011 at 9:54 PM, Paul E. McKenney wrote: > On Tue, May 10, 2011 at 01:52:52PM -0700, Yinghai Lu wrote: >> On 05/10/2011 12:32 PM, Paul E. McKenney wrote: >> > On Tue, May 10, 2011 at 11:04:57AM -0700, Yinghai Lu wrote: >> >> On 05/10/2011 01:56 AM, Paul E. McKenney wrote: >> >>> On Mon, May 09, 2011 at 02:09:21PM -0700, Yinghai Lu wrote: >> >>>> On Mon, May 9, 2011 at 12:36 AM, Ingo Molnar wrote: >> >>>>> >> >>>>> * Paul E. McKenney wrote: >> >>>>> >> >>>>>> Hello, Ingo, >> >>>>>> >> >>>>>> This pull request covers RCU chnages for 2.6.40.  The major new features >> >>>>>> are RCU priority boosting and the addition of kfree_rcu(), the latter >> >>>>>> courtesy of Lai Jiangshan.  These two features cover well over half >> >>>>>> of the commits.  There are a number of smaller features and bug fixes. >> >>>>>> All have been sent to LKML in the following batches: >> >>>>>> >> >>>>>> 0.    https://lkml.org/lkml/2011/2/22/660: RCU priority boosting preview >> >>>>>> 1.    https://lkml.org/lkml/2011/5/1/19: RCU priority boosting, kfree_rcu() >> >>>>>> 2.    https://lkml.org/lkml/2011/5/2/40: More uses of kfree_rcu() >> >>>>>> 3.    https://lkml.org/lkml/2011/5/8/60: miscellaneous >> >>>>>> >> >>>>>> The kfree_rcu() uses in the pull request have Acked-by:s from the >> >>>>>> maintainers.  I have some additional kfree_rcu() requests that lack >> >>>>>> Acked-by:s, and I will deal with these later. >> >>>>>> >> >>>>>> These channges are available in the -rcu git repository at: >> >>>>>> >> >>>>>>   git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git rcu/next >> >>>>> >> >>>>> Pulled, thanks a lot Paul! >> >>>>> >> >>>> >> >>>> it seems with this one in tip, my 8 sockets test setup will report cpu stall. >> >>>> >> >>>> after hard code to enable rcu_cpu_stall_suppress >> >>>> >> >>>> Index: linux-2.6/kernel/rcutree.c >> >>>> =================================================================== >> >>>> --- linux-2.6.orig/kernel/rcutree.c >> >>>> +++ linux-2.6/kernel/rcutree.c >> >>>> @@ -174,7 +174,7 @@ module_param(blimit, int, 0); >> >>>>  module_param(qhimark, int, 0); >> >>>>  module_param(qlowmark, int, 0); >> >>>> >> >>>> -int rcu_cpu_stall_suppress __read_mostly; >> >>>> +int rcu_cpu_stall_suppress __read_mostly = 1; >> >>>>  module_param(rcu_cpu_stall_suppress, int, 0644); >> >>>> >> >>>>  static void force_quiescent_state(struct rcu_state *rsp, int relaxed); >> >>>> >> >>>> will get system hang after pnp ACPI init. >> >>> >> >>> Could you please send the stack traces from the RCU CPU stall?  Also, >> >>> you do have ce31332d3c77532d6ea97ddcb475a2b02dd358b4 applied, correct? >> >>> >> >>>                                                   Thanx, Paul >> >> >> >> Do not have time to bisect it at this point. >> > >> > Could you please send the stack traces from the RCU CPU stall? > > Thank you!  OK, so CPU 0 has not been responding, despite resched IPIs. > Everyone is idle, except for CPU 124, which detected the stall, and > possibly CPU 0, which has csum_partial_copy_generic() on the stack, though > that looks like a backtrace error to me.  The fact that it hangs if you > disable RCU CPU stall detection leads me to believe that something real > is being detected. the problem is that now I can not disable RCU CPU stall detection any more. Thanks Yinghai