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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 2563EC19759 for ; Thu, 1 Aug 2019 12:35:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECC0320665 for ; Thu, 1 Aug 2019 12:35:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564662911; bh=kjDx05icsd9r8HchwA5lA8bdePuS2djW5cuDy1D6MLw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=YbiHI1s/GOFlAJMdSs1xB8zt1Vq/AXXOnMYnEIoPJ6qdXXCI9sbvYjP6v/iDfhXd7 pfflTAlJa0RO3608SWiNkWOCi+YOKiyKd0+raiAEN3ksKP23DQ/bf36kGu2MrdoXSs IzT/v2BzzkdJeoTLM/iTq9Bl3MMCCLPkcVjMg2ZU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731333AbfHAMfK (ORCPT ); Thu, 1 Aug 2019 08:35:10 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:51136 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726422AbfHAMfJ (ORCPT ); Thu, 1 Aug 2019 08:35:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sirena.org.uk; s=20170815-heliosphere; h=In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=jn+TAs+wP2cc9h9jrK3a2n7Js2n4wFFbww5v7SUsvYc=; b=K7gXYWuRuzu1ZyYPKhgOzFdru SOUloJZGMoeo0cQCok3RcyjmDDBPVw4OZm/PQZM9vdRbAt8fu0Ozl7/rtJaTQHguXd+lDUWVot4Ii bx/2KN50JjOk3NcOwbelhXY6O6AWGbEOvFVFIOX418QS0JVDiN+2gG+r/2J2hv/jBytaA=; Received: from cpc102320-sgyl38-2-0-cust46.18-2.cable.virginm.net ([82.37.168.47] helo=ypsilon.sirena.org.uk) by heliosphere.sirena.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1htAIS-0004dZ-Af; Thu, 01 Aug 2019 12:35:04 +0000 Received: by ypsilon.sirena.org.uk (Postfix, from userid 1000) id 570B02742C48; Thu, 1 Aug 2019 13:35:03 +0100 (BST) Date: Thu, 1 Aug 2019 13:35:03 +0100 From: Mark Brown To: Peter Zijlstra Cc: Enric Balletbo i Serra , mingo@kernel.org, linux-kernel@vger.kernel.org, Benson Leung , Guenter Roeck , linux-spi@vger.kernel.org, Doug Anderson Subject: Re: [PATCH 5/5] spi: Reduce kthread priority Message-ID: <20190801123503.GC5488@sirena.org.uk> References: <20190801111348.530242235@infradead.org> <20190801111541.917256884@infradead.org> <640721f8-8a20-b161-473f-98a9dbc053cc@collabora.com> <20190801121718.GE31381@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="S1BNGpv0yoYahz37" Content-Disposition: inline In-Reply-To: <20190801121718.GE31381@hirez.programming.kicks-ass.net> X-Cookie: Love thy neighbor, tune thy piano. User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --S1BNGpv0yoYahz37 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Aug 01, 2019 at 02:17:18PM +0200, Peter Zijlstra wrote: > I'm thinking that isn't true 99% of the time, except of course when that > bandsaw emergency break is attached through SPI, but in that case the > admin can very well chrt the prio of this thread. The SPI thread isn't usually RT, it's only made RT if something in the system asks for it - the reason the ChromeOS people got CCed in is that some of their embedded controllers are very fragile and need super tight timing on some of the interactions over their control interface so they're one of the users here. Of course everyone is then going to claim that their usage is the most critical usage in the system, and they may well even be right, but I do tend to agree that just any old RT priority is probably a sensible default since for most cases there will be few if any other RT tasks anyway. --S1BNGpv0yoYahz37 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl1C3HYACgkQJNaLcl1U h9Alfwf6AugMBoXb++tNEYu9FBXmJsqiEoyD4n90hKDCTMRgF8sokxYAvUGTJzQQ iE0h+bYBl8vU2eJG4nCGRQZRRFmACX/amPXBY82xVOcBooUZ74g+igbRW35/nSuR vtE8DGr2jugTuTznssPMVCKYSYcvxvV3PRzdvx30phQCUtqtBlpEFWVHH0FtacEM UQPH01JiVA7QcE/ZqYXAR7Jsgfm7kNEMTAgaxvGUhYVVnHmWwZnioK8Ke/cE75SL Uwa38z692JzCAL0c5qepeOF2aXLAjt+F1IPFWGrAjgmjRjqjS4ZzZWTGAWMMPscP 2Y/hPW2i7J6cvNkLxXborjsKCte3iw== =t0Pu -----END PGP SIGNATURE----- --S1BNGpv0yoYahz37--