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=-2.8 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 C2737C43331 for ; Tue, 31 Mar 2020 13:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 93BFB20784 for ; Tue, 31 Mar 2020 13:36:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585661802; bh=0wlmQUBZo5JQSwVpgZYmAAGFKA9gYa02POOYuT/NF/4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gLLviLdOLfA0AM7tDTAW4uXzpaXCCb15Cfhw8N62oWIufgRHu5Ters3lIWJIpTo6G E3azIGiW2G8R/2xcsx6HY/BFXpDrh7r0FzDT/t1BD+IkQAUqHcgR6HwEtQ1W5j0FV1 ZMZRymxC6KoeTmOmZZilaz/epBfQpwWMvxrREIh0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730867AbgCaNgl (ORCPT ); Tue, 31 Mar 2020 09:36:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:45506 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730216AbgCaNgl (ORCPT ); Tue, 31 Mar 2020 09:36:41 -0400 Received: from localhost (lfbn-ncy-1-985-231.w90-101.abo.wanadoo.fr [90.101.63.231]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 06F322071A; Tue, 31 Mar 2020 13:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585661800; bh=0wlmQUBZo5JQSwVpgZYmAAGFKA9gYa02POOYuT/NF/4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WeN+KF4FMTmmdRpDwvkiOdJiPOpuEnsz2kPVA/67mRSyyFkwjPI03/JZE9kQ2W6yJ inp5ZXip+joaQID7x5NHB2wuePcNqrS5pjto3R/OhYezAlJEpkxZPM2+Ul/ZWSDCzn GWvCwlG39jbXz48iCUHOzQHhTzEQZRaaf8CngRIc= Date: Tue, 31 Mar 2020 15:36:38 +0200 From: Frederic Weisbecker To: Marcelo Tosatti Cc: linux-kernel@vger.kernel.org, Frederic Weisbecker , Chris Friesen , Thomas Gleixner , Peter Zijlstra , Andrew Morton , Jim Somerville , Christoph Lameter Subject: Re: [patch 2/3] isolcpus: affine kernel threads to specified cpumask Message-ID: <20200331133637.GB24647@lenoir> References: <20200328152117.881555226@redhat.com> <20200328152503.225876188@redhat.com> <20200331005706.GA24647@lenoir> <20200331115014.GA2182@fuller.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331115014.GA2182@fuller.cnet> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 31, 2020 at 08:50:14AM -0300, Marcelo Tosatti wrote: > On Tue, Mar 31, 2020 at 02:57:08AM +0200, Frederic Weisbecker wrote: > > On Sat, Mar 28, 2020 at 12:21:19PM -0300, Marcelo Tosatti wrote: > Hi Frederic, > > > So, what about what I suggested with having "unbound" instead, which > > includes all the CPU-unbound work? > > > > HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_SCHED > > After more thought, it would share certain flags with nohz_full=, which > seemed confusing. In fact I think we should also add HK_FLAG_KTHREAD | HK_FLAG_SCHED to nohz_full= nohz_full is merely just a shortcut to isolate the tick and the unbound works anyway. > > > (and yes your suggestion of including HK_FLAG_SCHED is good). > > > > Because I don't see the point of exposing kthread isolation alone as an ABI > > so far. > > > > Later I suspect I'll turn all these flags into a single HK_FLAG_UNBOUND. > > How about keeping the flags separate, and then on top of that do > an "unbound" flag (less typing needed). > > This would allow users to combine the individual flags (again, useful > for debugging) while at the same time having an option which groups > all the others? Well, I'd rather not expose all the individual bits to the user. They rely on kernel implementation details that shouldn't be much useful to the user. As for internal kernel use, not sure this will ease debugging... Thanks.