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=-7.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,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 B400EC3815B for ; Mon, 20 Apr 2020 16:02:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 917D02078E for ; Mon, 20 Apr 2020 16:02:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587398570; bh=koM17VsUIjN22KW0gYBGciditqoq/vpfeCTdStzZrDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=serHBILo1tmWJXAYIHL+dvDwXpdti3OH5yoSqiR2BkfENt7vo+Kq6uEuxJC/UaSdG U6pTUyAKpg+sZZRsQXEdwa6oaLoupflhRCSzkarz1eCaEySnF9XdEqJkNyZyvX5Ud8 YLZf62C0Rk4W82iHPhTWrQosgRQzFGFJTRFuNSbg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726495AbgDTQCt (ORCPT ); Mon, 20 Apr 2020 12:02:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:45084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726067AbgDTQCt (ORCPT ); Mon, 20 Apr 2020 12:02:49 -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 58C5220775; Mon, 20 Apr 2020 16:02:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587398568; bh=koM17VsUIjN22KW0gYBGciditqoq/vpfeCTdStzZrDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JuQN31/97Tv3UOP/mqB4qg99JuUoeHH5P1zozM3N87TFBNq3UzcZatt1TrSTBYEUL QJXlLa73Ju7reDsInSH3lFrQ2LwFyDx1+FNZ0ldO6JB96ZF9QMs8Tidqiskt0BbMNJ fwdG+1XjHqGZHivHv7L3f8Y6alDwzeup21T1q/Iw= Date: Mon, 20 Apr 2020 18:02:46 +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 0/4] affine kernel threads to nohz_full= cpumask (v4) Message-ID: <20200420160245.GA10024@lenoir> References: <20200401121018.104226700@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200401121018.104226700@redhat.com> 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 Wed, Apr 01, 2020 at 09:10:18AM -0300, Marcelo Tosatti wrote: > This is a kernel enhancement that configures the cpu affinity of kernel > threads via kernel boot option nohz_full=. > > When this option is specified, the cpumask is immediately applied upon > thread launch. This does not affect kernel threads that specify cpu > and node. > > This allows CPU isolation (that is not allowing certain threads > to execute on certain CPUs) without using the isolcpus=domain parameter, > making it possible to enable load balancing on such CPUs > during runtime (see kernel-parameters.txt). > > Note-1: this is based off on Wind River's patch at > https://github.com/starlingx-staging/stx-integ/blob/master/kernel/kernel-std/centos/patches/affine-compute-kernel-threads.patch > > Difference being that this patch is limited to modifying > kernel thread cpumask: Behaviour of other threads can > be controlled via cgroups or sched_setaffinity. > > Note-2: Wind River's patch was based off Christoph Lameter's patch at > https://lwn.net/Articles/565932/ with the only difference being > the kernel parameter changed from kthread to kthread_cpus. > > v2: use isolcpus= subcommand (Thomas Gleixner) > > v3: s/MontaVista/Wind River/ on changelog (Chris Friesen) > documentation updates (Chris Friesen) > undeprecate isolcpus (Chris Friesen) > general cleanups (Frederic Weisbecker) > separate cpu_possible_mask kthread > mask change (Frederic Weisbecker) > > v4: disable idle load balancing for nohz_full= > use nohz_full= option for kthread isolation (Frederic Weisbecker) > Thanks for the patches. I'm applying them, I may add a few details to the changelogs and stuff.