Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759280AbYCGHqm (ORCPT ); Fri, 7 Mar 2008 02:46:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755135AbYCGHqd (ORCPT ); Fri, 7 Mar 2008 02:46:33 -0500 Received: from mga11.intel.com ([192.55.52.93]:34722 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754748AbYCGHqc (ORCPT ); Fri, 7 Mar 2008 02:46:32 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,460,1199692800"; d="scan'208";a="304294476" Subject: Re: [BUG 2.6.25-rc3] scheduler/hotplug: some processes are dealocked when cpu is set to offline From: Yi Yang Reply-To: yi.y.yang@intel.com To: Oleg Nesterov Cc: Gautham R Shenoy , Ingo Molnar , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , Thomas Gleixner In-Reply-To: <1204641443.3842.46.camel@yangyi-dev.bj.intel.com> References: <1204483329.3607.8.camel@yangyi-dev.bj.intel.com> <20080303153154.GA11288@in.ibm.com> <1204555505.3842.4.camel@yangyi-dev.bj.intel.com> <20080304052613.GA28632@in.ibm.com> <20080304150107.GA564@tv-sign.ru> <1204641443.3842.46.camel@yangyi-dev.bj.intel.com> Content-Type: text/plain Organization: Intel Date: Fri, 07 Mar 2008 04:05:10 +0800 Message-Id: <1204833910.3842.58.camel@yangyi-dev> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 (2.10.1-4.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1672 Lines: 68 I found priority of some processes is always 0 but they are highly related to this kind of deadlock. What does Priority 0 mean? When and in which case is it's priority changed to 0? When can it's priority be restored to one higher value. A simple script to get priority 0: =================================================================== #!/bin/sh for file in `ls /proc/*/sched` do prio=`grep prio $file | awk '{print $3;}'` if [ "X$prio" == "X0" ] ; then echo "`head -n 1 $file | awk '{print $1}'`: $prio" fi done ================================================================== [root@harwich-rh ~]# ./lsprio migration/3: 0 migration/4: 0 migration/5: 0 migration/6: 0 migration/7: 0 migration/8: 0 migration/9: 0 migration/10: 0 migration/11: 0 migration/12: 0 migration/0: 0 migration/13: 0 migration/14: 0 migration/15: 0 grep: /proc/5244/sched: No such file or directory kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 kstopmachine: 0 watchdog/1: 0 migration/2: 0 [root@harwich-rh ~]# ps aux | grep "R<" root 8 0.0 0.0 0 0 ? R< 19:29 0:00 [watchdog/1] root 6987 0.0 0.0 61144 708 pts/2 R+ 20:16 0:00 grep R< [root@harwich-rh ~]# -- 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/