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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 970A3C00140 for ; Thu, 11 Aug 2022 02:11:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233677AbiHKCLx (ORCPT ); Wed, 10 Aug 2022 22:11:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233587AbiHKCLv (ORCPT ); Wed, 10 Aug 2022 22:11:51 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C943E5C9D6 for ; Wed, 10 Aug 2022 19:11:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=h+uF+lQ30edn3NbcymNy0iGU9+MYf3yjA5N14fvFiPQ=; b=0Q8tq7jUc4A0SFcyDQhh3WdM+L S1OqTy69AA8CVe4JNPb4jRVFLx+KN2mSQsh6tpr82QmAWV5LLiF7/8MdDrLOMn8YU9uQdKTd+eCv+ JOfhL/iF31PJjUxGiqfxV3lOKVbALeBqys41HYGEkqmjBLsXyHDQ3D4jrGXPOhkX0qtEZXdQLPd8x Cs1WO7YKQdjMcDuw7YjkUuu14qDb2eYSuh+3lQZ4vNWiXEH8EESxjC7X3iBxkx7A8L20aaFV6G4GP kUkz6PbQtWkilanOuLpebofSaQo/R95Y9csKdUoYqqujQcU8h+Us80eBmKq9ZY+rka0CfkfnIjbic 872O4Gyw==; Received: from [2601:1c0:6280:3f0::a6b3] by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLxfi-003NZE-Dq; Thu, 11 Aug 2022 02:11:42 +0000 Message-ID: <9d2f1a82-8e0f-c0ad-e23f-e0d00905a596@infradead.org> Date: Wed, 10 Aug 2022 19:11:40 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [RFC][PATCH 1/2] sched: Avoid placing RT threads on cores handling long softirqs Content-Language: en-US To: John Stultz , LKML Cc: Connor O'Brien , John Dias , Rick Yiu , John Kacur , Qais Yousef , Chris Redpath , Abhijeet Dharmapurikar , Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Thomas Gleixner , kernel-team@android.com, "J . Avila" References: <20220811015758.3001641-1-jstultz@google.com> <20220811015758.3001641-2-jstultz@google.com> From: Randy Dunlap In-Reply-To: <20220811015758.3001641-2-jstultz@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/10/22 18:57, John Stultz wrote: > diff --git a/init/Kconfig b/init/Kconfig > index c7900e8975f1..b0dde2771314 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1278,6 +1278,17 @@ config SCHED_AUTOGROUP > desktop applications. Task group autogeneration is currently based > upon task session. > > +config RT_SOFTIRQ_OPTIMIZATION > + bool "Improve RT scheduling during long softirq execution" > + depends on ARM64 > + depends on SMP > + default n > + help > + Enable an optimization which tries to avoid placing RT tasks on CPUs Above line is indented with spaces only. :( > + occupied by nonpreemptible tasks, such as a long softirq or CPUs > + which may soon block preemptions, such as a CPU running a ksoftirq > + thread which handles slow softirqs. All help text lines should be indented with one tab + 2 spaces, per Documentation/process/coding-style.rst. (The 3 lines above have one tab + one space.) -- ~Randy