Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755803AbbDGPcy (ORCPT ); Tue, 7 Apr 2015 11:32:54 -0400 Received: from forward-corp1g.mail.yandex.net ([95.108.253.251]:43802 "EHLO forward-corp1g.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753117AbbDGPcv (ORCPT ); Tue, 7 Apr 2015 11:32:51 -0400 Authentication-Results: smtpcorp1m.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Message-ID: <5523F89F.1070502@yandex-team.ru> Date: Tue, 07 Apr 2015 18:32:47 +0300 From: Konstantin Khlebnikov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , linux-kernel@vger.kernel.org, Ben Segall , Roman Gushchin Subject: Re: [PATCH RFC] sched/fair: fix sudden expiration of cfq quota in put_prev_task() References: <20150403124138.1349.11633.stgit@buzz> <551E8CC5.30906@yandex-team.ru> <20150407125251.GM23123@twins.programming.kicks-ass.net> <20150407134758.GR24151@twins.programming.kicks-ass.net> <20150407151246.GS24151@twins.programming.kicks-ass.net> In-Reply-To: <20150407151246.GS24151@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1502 Lines: 54 On 07.04.2015 18:12, Peter Zijlstra wrote: > On Tue, Apr 07, 2015 at 03:47:58PM +0200, Peter Zijlstra wrote: >> Lemme think a bit more on that. > > So going by 734ff2a71f9e ("sched/rt: Fix picking RT and DL tasks from > empty queue") something like this would be called for. > > --- > kernel/sched/fair.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index fdae26eb7218..1e47f816c976 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5175,6 +5175,21 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev) > return p; > simple: > cfs_rq = &rq->cfs; We don't need this if prev isn't from fair_sched_class: first "goto simple" should go directly to "if (!cfs_rq->nr_running)". > + > + if (cfs_bandwidth_used()) { > + /* > + * We may dequeue prev's cfs_rq in put_prev_task(). > + * So, we update time before cfs_rq->nr_running check. > + */ > + if (prev->on_rq) > + update_curr(cfs_rq); > + > + se = &prev->se; > + for_each_sched_entity(se) { Probably update_curr() should be inside loop too? > + cfs_rq = cfs_rq_of(se); > + check_cfs_rq_runtime(cfs_rq); > + } > + } > #endif > > if (!cfs_rq->nr_running) > -- Konstantin -- 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/