Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752801AbaKQQyH (ORCPT ); Mon, 17 Nov 2014 11:54:07 -0500 Received: from forward20.mail.yandex.net ([95.108.253.145]:44643 "EHLO forward20.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752529AbaKQQyE (ORCPT ); Mon, 17 Nov 2014 11:54:04 -0500 From: Kirill Tkhai To: Wanpeng Li Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , linux-kernel@vger.kernel.org, Kirill Tkhai Subject: Re:[PATCH v5] sched/deadline: support dl task migration during cpu hotplug MIME-Version: 1.0 Message-Id: <391401416243011@web3h.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Mon, 17 Nov 2014 19:50:11 +0300 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=utf-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Hi Kirill, > On Thu, Nov 13, 2014 at 01:21:31PM +0300, Kirill Tkhai wrote: > >>>>>>> @@ -1185,8 +1223,9 @@ static int find_later_rq(struct task_struct *task) >>>>>>> * We have to consider system topology and task affinity >>>>>>> * first, then we can look for a suitable cpu. >>>>>>> */ >>>>>>> - cpumask_copy(later_mask, task_rq(task)->rd->span); >>>>>>> - cpumask_and(later_mask, later_mask, cpu_active_mask); >>>>>>> + cpumask_copy(later_mask, cpu_active_mask); >>>>>>> + if (likely(task_rq(task)->online)) >>>>>>> + cpumask_and(later_mask, later_mask, task_rq(task)->rd->span); >>>>>>> cpumask_and(later_mask, later_mask, &task->cpus_allowed); >>>>>>> best_cpu = cpudl_find(&task_rq(task)->rd->cpudl, >>>>>>> task, later_mask); >>>> >>>> Also, we should think about the following situation. >>>> >>>> DL task is left on dead rq. In your scheme it will be moved by the timer. >>>> But what will be if somebody changes the class of the task (before timer)? >>> >>> I think timer will be cancelled in switched_from_dl(). >> >> Yeah, but nobody will move this task to alive rq. >> >>> Regards, >>> Wanpeng Li >>> >>>> In this case the task still remains on dead rq. >>>> >>>> We should handle this situation in some way. > > Your proposal is a great appreciated. Sadly, I‘m travelling at the moment, I‘m not able to do something till december. > Regards, > Wanpeng Li > >>>> Kirill >>>> >>>> -- >>>> 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/ > > -- > 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/ -- 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/