From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH][RFC] kernel/cpu: do not change the cpus_allowed of the current task when unplugging cpus Date: Fri, 7 Jun 2013 11:05:43 +0200 Message-ID: <20130607090543.GD10280@linutronix.de> References: <1368699439-13034-1-git-send-email-chenhui.zhao@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, leoli@freescale.com, scottwood@freescale.com, Priyanka.Jain@freescale.com To: Zhao Chenhui Return-path: Received: from www.linutronix.de ([62.245.132.108]:45122 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671Ab3FGJFo (ORCPT ); Fri, 7 Jun 2013 05:05:44 -0400 Content-Disposition: inline In-Reply-To: <1368699439-13034-1-git-send-email-chenhui.zhao@freescale.com> Sender: linux-rt-users-owner@vger.kernel.org List-ID: * Zhao Chenhui | 2013-05-16 18:17:19 [+0800]: >We found a problem. When a cpu is brought down using _cpu_down(), >the corresponding cpu bit in the cpus_allowed of the current task is >cleared. But this bit will not be set when the same cpu is online again. >Then, the current task and its child processes will not be allowed to >run on this cpu. Isn't this what should happen? This also happens on mainline if you leave the RT bits out, right? You should be able to put the task back on the CPU once the CPU is up again. Sebastian