Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755366AbaBUMJd (ORCPT ); Fri, 21 Feb 2014 07:09:33 -0500 Received: from forward3h.mail.yandex.net ([84.201.187.148]:49406 "EHLO forward3h.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755261AbaBUMJc (ORCPT ); Fri, 21 Feb 2014 07:09:32 -0500 From: Kirill Tkhai To: Peter Zijlstra Cc: "linux-kernel@vger.kernel.org" , Juri Lelli , Steven Rostedt , Ingo Molnar In-Reply-To: <128831392982418@web15j.yandex.ru> References: <230991392848160@web13m.yandex.ru> <20140221103715.GP9987@twins.programming.kicks-ass.net> <128831392982418@web15j.yandex.ru> Subject: Re: [RFC] sched/deadline: Prevent rt_time growth to infinity MIME-Version: 1.0 Message-Id: <311621392984565@web3h.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Fri, 21 Feb 2014 16:09:25 +0400 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=koi8-r Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 21.02.2014, 15:39, "Kirill Tkhai" : > 21.02.2014, 14:37, "Peter Zijlstra" : > >> ?On Thu, Feb 20, 2014 at 02:16:00AM +0400, Kirill Tkhai wrote: >>> ??Since deadline tasks share rt bandwidth, we must care about >>> ??bandwidth timer set. Otherwise rt_time may grow up to infinity >>> ??in update_curr_dl(), if there are no other available RT tasks >>> ??on top level bandwidth. >>> >>> ??I'm going to decide the problem the way below. Almost untested >>> ??because of I skipped almost all of recent patches which haveto be applied from lkml. >>> >>> ??Please say, if I skipped anything in idea. Maybe better put >>> ??start_top_rt_bandwidth() into set_curr_task_dl()? >> ?How about we only increment rt_time when there's an RT bandwidth timer >> ?active? > > This case RT and DL may eat all the time: > > -------------- ?time ------------------> > |RT's working |DL's working| > ---------------------------- > |rt_runtime ??| ???????????| > ---------------------------- > | ???????rt_period ????????| > > Or at least more, than it's allowed. > > It looks like, if we want to limit time of high priority classes > execution, we have to set the timer anyway. Oh, above is confusing. Sorry. I mean one RT task and ----------------- time --------------------------> |DL's working |RT's working| |DL's working | -------------------------------------------------- | |rt_runtime | | | -------------------------------------------------- | | rt_period | | In this case FAIR receives less ratio, than (rt_period-rt_runtime)/rt_period. >> ?--- >> ?--- a/kernel/sched/rt.c >> ?+++ b/kernel/sched/rt.c >> ?@@ -568,6 +568,12 @@ static inline struct rt_bandwidth *sched > > [snipped by dumb mail client] > -- > 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/