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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 277FBC282DD for ; Thu, 9 Jan 2020 15:30:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA65820673 for ; Thu, 9 Jan 2020 15:30:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="mP6aEY6Z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732433AbgAIPaL (ORCPT ); Thu, 9 Jan 2020 10:30:11 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:39739 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731052AbgAIPaK (ORCPT ); Thu, 9 Jan 2020 10:30:10 -0500 Received: by mail-qt1-f193.google.com with SMTP id e5so6163692qtm.6 for ; Thu, 09 Jan 2020 07:30:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Twt5NWaUi/oSEH7E7cF5IXCKhNEDwF3MBqc2/OHa0qI=; b=mP6aEY6Zt6ZJV1KldQt+uvcIwh+jnX8fG0AASAukPxhv3MZJ31M7IZZw8OvADx8CX+ ko1Ht33JO4QQXJNfLTy4FBEJxH4VnCqpgebtF05EdN+bl1PINxSe24VIJlPhnKMTXb2n 6V++mv5xH5OyzHiLQiPbd7bBbbU3CBpTZXntC8SuOKPw0p8L6LfIUkc3qbKjzuo9UqOt tQMGBWVoKy9fTTA+gPjhD3U13yWqzBkHw+Ud9d3d1VchhABkLARXNmsHwk4R2e9q77vt SShw3rLMuF97Ay8nCJ9l6mVpAg0rvj8yWuVHH9J6UYOjnV9Qfke3/hVt8OVZRPDzZMgd LiIQ== 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; bh=Twt5NWaUi/oSEH7E7cF5IXCKhNEDwF3MBqc2/OHa0qI=; b=dqAqUcbeuXNwQvXIkms4WZD4hQ0MIA7VcgBo2IMCy6XfyWxEGtkeRe8pqCwq5ig0rj EObS0pxFNjarP7Inu9bDx5w8kbvbVLmE5rxVNLery0ELHGyixyVhuVHK3PUxy10gZOJ1 JErsSSgQqkKqsom35p9aZmbyiq6WZ1e/I58nEgQut8+W9QKfvOL2j+wdB/nwcrVncQDD Ra1zKEC+hG6axhf32f4MSO87qpbomvrCj387i3pzSoVRXbNllpy0eOcVwxXgMzb6REU5 kE/ufb/GJXB2aoUvN7wGQWrcD7kM7fddMFWH77wzdLdcT1YV+8U1JYqf3hNgoKFg3FJr 3Amw== X-Gm-Message-State: APjAAAVarwRnFTpkjN7KmyRwo0ZAf4S9WaIKe8GgR9SAYQ/lEoJ3Deao /au+JQKLR3vtjyicb2OCqMkSPA== X-Google-Smtp-Source: APXvYqwTFzAQQ9478bLzzuI3PUeKPzbIM/CzuF7HZJv35tW58SLdFtokdB8zEConeqwSRh4zML799A== X-Received: by 2002:aed:3e21:: with SMTP id l30mr8663136qtf.357.1578583804811; Thu, 09 Jan 2020 07:30:04 -0800 (PST) Received: from localhost ([2620:10d:c091:500::1:d72d]) by smtp.gmail.com with ESMTPSA id b40sm2813472qta.86.2020.01.09.07.30.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jan 2020 07:30:03 -0800 (PST) Date: Thu, 9 Jan 2020 10:30:02 -0500 From: Johannes Weiner To: Peter Zijlstra Cc: Wang Long , mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/psi: create /proc/pressure and /proc/pressure/{io|memory|cpu} only when psi enabled Message-ID: <20200109153002.GA8547@cmpxchg.org> References: <1576672698-32504-1-git-send-email-w@laoqinren.net> <20200108135526.GH2844@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200108135526.GH2844@hirez.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 08, 2020 at 02:55:26PM +0100, Peter Zijlstra wrote: > On Wed, Dec 18, 2019 at 08:38:18PM +0800, Wang Long wrote: > > when CONFIG_PSI_DEFAULT_DISABLED set to N or the command line set psi=0, > > I think we should not create /proc/pressure and > > /proc/pressure/{io|memory|cpu}. > > > > In the future, user maybe determine whether the psi feature is enabled by > > checking the existence of the /proc/pressure dir or > > /proc/pressure/{io|memory|cpu} files. > > Works for me; Johannes? Seems reasonable, and the patch looks good to me. Acked-by: Johannes Weiner