From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F6F1C7618B for ; Mon, 29 Jul 2019 11:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4AF3820651 for ; Mon, 29 Jul 2019 11:45:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387750AbfG2Lp5 (ORCPT ); Mon, 29 Jul 2019 07:45:57 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:43736 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387638AbfG2Lp4 (ORCPT ); Mon, 29 Jul 2019 07:45:56 -0400 Received: by mail-wr1-f65.google.com with SMTP id p13so61457329wru.10 for ; Mon, 29 Jul 2019 04:45:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wswpQoJgwyGyzPq8XXsD+wjeWZTbEbjja41h5xGOJVQ=; b=ddz4Wor4yo8TmxH/uvHUEtv/+ZD88N5kD3iXKJe55xA17xsP3AWWW9F3z8Ta4be6kA XuXKQM+XxegdmkctCTzC4e5UiG+MySlTUFrl0HlGqApGgNgfJF9uXeDIUDQtYDpczjp3 7Jp2Yh8/bpZEa4MqbaTXIRDUpYouXZ+iFGAfSOur2UmD97540jocfdJ+ec7pG2/Tbai3 ZwuKb5e9DU/soMxrPdmuNpQGh6ni63Eg0mBMRArNTKBb7J/Ep2oV/HtbwZiYG+krtpSK LvKE5JuQGFO65vm7y6cQVnHcgjawFDJVwF0TK35sHBqk2wvwzSFlOLt06+63ELO7KHZr tnKQ== X-Gm-Message-State: APjAAAUI3RiyYpoPkyoCVeU4B1VcCTCKc+fU783jlQDcOszmbWBHfT/N YACvh/w+MZWwQXMNjzQvMq/PvQ== X-Google-Smtp-Source: APXvYqxe+aP64hAMwZCKl2r96RQuNJ8QO4qV5Nz/0wIXQvSs0/a1KeBhexRENJdUdvzJDmVJ3Lt07Q== X-Received: by 2002:a5d:498f:: with SMTP id r15mr113353676wrq.353.1564400754574; Mon, 29 Jul 2019 04:45:54 -0700 (PDT) Received: from t460s.bristot.redhat.com (nat-cataldo.sssup.it. [193.205.81.5]) by smtp.gmail.com with ESMTPSA id k17sm78744410wrq.83.2019.07.29.04.45.53 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 29 Jul 2019 04:45:53 -0700 (PDT) Subject: Re: [RFC][PATCH 01/13] sched/deadline: Impose global limits on sched_attr::sched_period To: Juri Lelli , Peter Zijlstra Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com, luca.abeni@santannapisa.it, balsini@android.com, dvyukov@google.com, tglx@linutronix.de, vpillai@digitalocean.com, rostedt@goodmis.org References: <20190726145409.947503076@infradead.org> <20190726161357.397880775@infradead.org> <20190729085711.GQ25636@localhost.localdomain> From: Daniel Bristot de Oliveira Message-ID: Date: Mon, 29 Jul 2019 13:45:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190729085711.GQ25636@localhost.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/07/2019 10:57, Juri Lelli wrote: > Hi, > > On 26/07/19 16:54, Peter Zijlstra wrote: >> Cc: Daniel Bristot de Oliveira >> Cc: Luca Abeni >> Cc: Juri Lelli >> Cc: Dmitry Vyukov >> Signed-off-by: Peter Zijlstra (Intel) >> --- >> include/linux/sched/sysctl.h | 3 +++ >> kernel/sched/deadline.c | 23 +++++++++++++++++++++-- >> kernel/sysctl.c | 14 ++++++++++++++ >> 3 files changed, 38 insertions(+), 2 deletions(-) >> >> --- a/include/linux/sched/sysctl.h >> +++ b/include/linux/sched/sysctl.h >> @@ -56,6 +56,9 @@ int sched_proc_update_handler(struct ctl >> extern unsigned int sysctl_sched_rt_period; >> extern int sysctl_sched_rt_runtime; >> >> +extern unsigned int sysctl_sched_dl_period_max; >> +extern unsigned int sysctl_sched_dl_period_min; >> + >> #ifdef CONFIG_UCLAMP_TASK >> extern unsigned int sysctl_sched_uclamp_util_min; >> extern unsigned int sysctl_sched_uclamp_util_max; >> --- a/kernel/sched/deadline.c >> +++ b/kernel/sched/deadline.c >> @@ -2597,6 +2597,14 @@ void __getparam_dl(struct task_struct *p >> } >> >> /* >> + * Default limits for DL period; on the top end we guard against small util >> + * tasks still getting rediculous long effective runtimes, on the bottom end we > s/rediculous/ridiculous/ > >> + * guard against timer DoS. >> + */ >> +unsigned int sysctl_sched_dl_period_max = 1 << 22; /* ~4 seconds */ >> +unsigned int sysctl_sched_dl_period_min = 100; /* 100 us */ > These limits look sane to me. I've actually been experimenting with 10us > period tasks and throttling seemed to behave fine, but I guess 100us is > a saner default. > > So, (with a few lines of changelog :) > > Acked-by: Juri Lelli Looks sane to me too! Acked-by: Daniel Bristot de Oliveira -- Daniel