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=-13.2 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL 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 2DCAFC4BA24 for ; Thu, 27 Feb 2020 13:00:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 060322469C for ; Thu, 27 Feb 2020 13:00:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IARaMUZP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729120AbgB0NAH (ORCPT ); Thu, 27 Feb 2020 08:00:07 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:53357 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728977AbgB0NAH (ORCPT ); Thu, 27 Feb 2020 08:00:07 -0500 Received: by mail-wm1-f67.google.com with SMTP id f15so3459141wml.3 for ; Thu, 27 Feb 2020 05:00:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=lF1WpNMmDIC+u5WUFqN6XI3/wXMvIRCjntbaMdrFGfg=; b=IARaMUZPJiCDFrzzJwyWb6YRob1J06IUMUj73rqLrl3Ppn2wS5eJPgwlML7IHofhy/ 2vf5hO+Nxf4m1l3oC4JUcc7Hycie16A5bdmxyzvR8ybGG19Vv74J/0OdSSzOtXAIAtFm hMdlDcz5qhKEWvM924Bb6wqORS+DdqDMMh0H5v7DlndWs3/uUJKmmlF5c7Pnu8OdtuG1 VApamd3WADlVVWGzYbr2a6BxRq5U34ILOaDQhh/SURP7x9fisOuMZn2MG+h5CFPxnUuh Za4SaJk52aI2JKEpRn4Fpd6QCc2qeQcY9u1+vXWi/UPTVb7jpQ1tclDVVaEd2hmdcgV6 5/9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=lF1WpNMmDIC+u5WUFqN6XI3/wXMvIRCjntbaMdrFGfg=; b=a6ponZ2+b8rA9VdPJ1tLoAIsj4KT1CnP9Zb9SQR8LZXEq3lfqMOUFteOEjiz2/fhWU MRDjLRhO8LNFxB8AqcstCKgDUGZjrtHXU249RIZbIxd1rh+a3xa+YXkjgPFna2Wk+vM5 OxtzIm2Ac73EBLk/52aQa4jTDxAeEJVlaATHXLajIXw5sM4bn3yaiIDf6BjxeBTwRvYX J/PVploI2cK0WfIf8en7Z0BBAu6VXAqDmd0GqP6yt79tDpbSC0ZlqZHtP9DDuF+PEAvv brALXZFHWuqSxTdSyZl2YIINNOUmj2XbTB6nlR4B61xevqX4Z+PJO5XPMl6JSYteE3cO KOpA== X-Gm-Message-State: APjAAAXfSBAFT7dqdRTwdK4elMc+O9fogilBHroWJT2J/Qq+2Xzmb48P KgyJjubn/9a3MeQUb2Pl00VSaA== X-Google-Smtp-Source: APXvYqyJc8z85FxR6Y8xbHanOXMr3EKjgHVQ0zhtwSRKjHALBfFlCDS/ccmFZBafwRz3YaXDguz5LA== X-Received: by 2002:a7b:c119:: with SMTP id w25mr5324707wmi.116.1582808405179; Thu, 27 Feb 2020 05:00:05 -0800 (PST) Received: from google.com ([2a00:79e0:d:110:d6cc:2030:37c1:9964]) by smtp.gmail.com with ESMTPSA id e18sm8033429wrw.70.2020.02.27.05.00.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Feb 2020 05:00:04 -0800 (PST) Date: Thu, 27 Feb 2020 13:00:01 +0000 From: Quentin Perret To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Peter Zijlstra , Ingo Molnar , Vincent Guittot , Dietmar Eggemann , morten.rasmussen@arm.com, Catalin Marinas , Will Deacon , Mark Rutland , kernel-team@android.com Subject: Re: [PATCH 1/2] sched/topology: Don't enable EAS on SMT systems Message-ID: <20200227130001.GA107011@google.com> References: <20200226164118.6405-1-valentin.schneider@arm.com> <20200226164118.6405-2-valentin.schneider@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200226164118.6405-2-valentin.schneider@arm.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 26 Feb 2020 at 16:41:17 (+0000), Valentin Schneider wrote: > EAS already requires asymmetric CPU capacities to be enabled, and mixing > this with SMT is an aberration, but better be safe than sorry. > > Signed-off-by: Valentin Schneider Acked-by: Quentin Perret Thanks, Quentin > --- > kernel/sched/topology.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 00911884b7e7..76cd0a370b9a 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -360,6 +360,10 @@ static bool build_perf_domains(const struct cpumask *cpu_map) > goto free; > } > > + /* EAS definitely does *not* handle SMT */ > + if (sched_smt_active()) > + goto free; > + > for_each_cpu(i, cpu_map) { > /* Skip already covered CPUs. */ > if (find_pd(pd, i)) > -- > 2.24.0 >