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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62349C433F5 for ; Tue, 5 Oct 2021 13:42:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4482261139 for ; Tue, 5 Oct 2021 13:42:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234761AbhJENoV (ORCPT ); Tue, 5 Oct 2021 09:44:21 -0400 Received: from foss.arm.com ([217.140.110.172]:43428 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233077AbhJENoT (ORCPT ); Tue, 5 Oct 2021 09:44:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DC89E1FB; Tue, 5 Oct 2021 06:42:28 -0700 (PDT) Received: from e113632-lin (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E6D8F3F70D; Tue, 5 Oct 2021 06:42:24 -0700 (PDT) From: Valentin Schneider To: Peter Zijlstra , Tim Chen Cc: Vincent Guittot , Barry Song <21cnbao@gmail.com>, Dietmar Eggemann , LKML , Ingo Molnar , Aubrey Li , Borislav Petkov , Daniel Bristot de Oliveira , Ben Segall , Catalin Marinas , Greg Kroah-Hartman , Guodong Xu , "H. Peter Anvin" , Jonathan Cameron , Juri Lelli , "Cc\: Len Brown" , ACPI Devel Maling List , LAK , Linuxarm , Mark Rutland , Mel Gorman , msys.mizuma@gmail.com, "Zengtao \(B\)" , "Rafael J. Wysocki" , Steven Rostedt , Barry Song , Sudeep Holla , Thomas Gleixner , "Rafael J. Wysocki" , Will Deacon , x86 , yangyicong Subject: Re: [PATCH RESEND 0/3] Represent cluster topology and enable load balance between clusters In-Reply-To: <20211005075001.GJ4323@worktop.programming.kicks-ass.net> References: <20210924085104.44806-1-21cnbao@gmail.com> <20211005075001.GJ4323@worktop.programming.kicks-ass.net> Date: Tue, 05 Oct 2021 14:42:17 +0100 Message-ID: <87tuhvlhae.mognet@arm.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/10/21 09:50, Peter Zijlstra wrote: > On Fri, Oct 01, 2021 at 04:22:46PM -0700, Tim Chen wrote: >> On Fri, 2021-10-01 at 16:57 +0200, Peter Zijlstra wrote: > >> > The one questino I have is, do we want default y? >> >> I also agree that default y is preferable. > > I'll change at least the x86 one to: > > default y > depends on SMP > Huh, so the arm64 SCHED_{SMT,MC} configs are defaultless (I added SCHED_SMT to arm64's defconfig not so long ago), but x86 has them default y, which I'm thinking is a tad better, and would be nice to harmonize. Unfortunately different architectures have their own dependency requirements - arm has ARM_CPU_TOPOLOGY, parisc has PARISC_CPU_TOPOLOGY... Would you hate making SCHED_* a "generic" config, with a common default and help text, and punt the arch specific stuff to an ARCH_SUPPORTS_* knob? Something like: arch/arm/Kconfig: select ARCH_SUPPORTS_SCHED_MC if ARM_CPU_TOPOLOGY init/Kconfig: config SCHED_MC def_bool y depends on ARCH_SUPPORTS_SCHED_MC && SMP