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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 3D21CC71155 for ; Mon, 30 Nov 2020 23:11:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8E76207BB for ; Mon, 30 Nov 2020 23:11:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bhfuwaps" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731256AbgK3XLV (ORCPT ); Mon, 30 Nov 2020 18:11:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730540AbgK3XLT (ORCPT ); Mon, 30 Nov 2020 18:11:19 -0500 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77CB2C0613D3 for ; Mon, 30 Nov 2020 15:10:39 -0800 (PST) Received: by mail-pl1-x632.google.com with SMTP id l11so19282plt.1 for ; Mon, 30 Nov 2020 15:10:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=aYm3p0jj0sVkrKj/bgD7NF1z8jv/Uy3ub0YZDSBHR1k=; b=bhfuwapsRiIEuUZn44jGMBQy5mdjGqflyjT/VJspv8bM+eZJELH98LLWw35xfA3RzG 9oIbCpG88nBDv1HTY3Mtd/Uzdlr2gulcs5NOhwWpLyvQIm3a88khs3A/5JSm+zkTAi+C H++CFP/tLOt2ycvlQ20uqeJB+0X4CV0m78LlTTjJfhzpqyfczntZc0KZ/rVBesbm7NZQ MgbCsoiq3UAh2hz6lOVT55EVWER5yUtSOu39Guelo5OkJ1o23sBBmP9TDN+EoQRcGYL2 3+G0+KrbN56KVoBuYjmttnS9/Oj3bsSWDyCwnpy1O6BF8R0YBSn3597leSxEU6kTa0pu fCtg== 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=aYm3p0jj0sVkrKj/bgD7NF1z8jv/Uy3ub0YZDSBHR1k=; b=lfJQy2haY2LQ8QpGLrrK1k6Uvyh5aANgiqxjAX0oSksjfvzjtglXPrTnLqj3u/fv7T FgJYjebPWHo+KaiKKskts4MoI85ShxVeOezKEYFkVzPMVHZ/0pJlE59A3i+ZsQQErmmu NH387G5TV5+7tfs9hRe/ziN1lXE3cr86zol5sVAuyXdvVQ7VI4jjqQ9Vblfrj+0B1Jf/ d5rsp1Q+5RNHN0S7Wu2OTavB9hPEGF7QvIXpjXMEUz8HFXCD7GWai3ZR+mEyW5YEAXHD kPhdW+pIxRnNsRJ4fi1xeIMspc/QYHseAYMzcHB1vSjAgZ38uF9POrZxnvPss6oJLrQ/ 0q8A== X-Gm-Message-State: AOAM532/4m4+ATXMJKUW7zxihC6SR6CnNuEYkxsUC+PGpbvYfXg2ZTvz qKfUIYHnNfzG/lacti8TMVc= X-Google-Smtp-Source: ABdhPJwBPdpAIryvVStwofSzNkKPyurPV69Nf+Dj6qCm3AijHsFH+VF4PejkGmbtb/1KmtLtLAQVJQ== X-Received: by 2002:a17:90b:b15:: with SMTP id bf21mr114253pjb.21.1606777838904; Mon, 30 Nov 2020 15:10:38 -0800 (PST) Received: from localhost (61-68-227-232.tpgi.com.au. [61.68.227.232]) by smtp.gmail.com with ESMTPSA id m9sm12438pfh.94.2020.11.30.15.10.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Nov 2020 15:10:37 -0800 (PST) Date: Tue, 1 Dec 2020 10:10:34 +1100 From: Balbir Singh To: Peter Zijlstra Cc: "Joel Fernandes (Google)" , Nishanth Aravamudan , Julien Desfossez , Tim Chen , Vineeth Pillai , Aaron Lu , Aubrey Li , tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, torvalds@linux-foundation.org, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Phil Auld , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , vineeth@bitbyteword.org, Chen Yu , Christian Brauner , Agata Gruza , Antonio Gomez Iglesias , graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com, pjt@google.com, rostedt@goodmis.org, derkling@google.com, benbjiang@tencent.com, Alexandre Chartre , James.Bottomley@hansenpartnership.com, OWeisse@umich.edu, Dhaval Giani , Junaid Shahid , jsbarnes@google.com, chris.hyser@oracle.com, Ben Segall , Josh Don , Hao Luo , Tom Lendacky , Aubrey Li , "Paul E. McKenney" , Tim Chen Subject: Re: [PATCH -tip 26/32] sched: Add a second-level tag for nested CGroup usecase Message-ID: <20201130231034.GF473773@balbir-desktop> References: <20201117232003.3580179-1-joel@joelfernandes.org> <20201117232003.3580179-27-joel@joelfernandes.org> <20201125134237.GZ2414@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201125134237.GZ2414@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 25, 2020 at 02:42:37PM +0100, Peter Zijlstra wrote: > On Tue, Nov 17, 2020 at 06:19:56PM -0500, Joel Fernandes (Google) wrote: > > From: Josh Don > > > > Google has a usecase where the first level tag to tag a CGroup is not > > sufficient. So, a patch is carried for years where a second tag is added which > > is writeable by unprivileged users. > > > > Google uses DAC controls to make the 'tag' possible to set only by root while > > the second-level 'color' can be changed by anyone. The actual names that > > Google uses is different, but the concept is the same. > > > > The hierarchy looks like: > > > > Root group > > / \ > > A B (These are created by the root daemon - borglet). > > / \ \ > > C D E (These are created by AppEngine within the container). > > > > The reason why Google has two parts is that AppEngine wants to allow a subset of > > subcgroups within a parent tagged cgroup sharing execution. Think of these > > subcgroups belong to the same customer or project. Because these subcgroups are > > created by AppEngine, they are not tracked by borglet (the root daemon), > > therefore borglet won't have a chance to set a color for them. That's where > > 'color' file comes from. Color could be set by AppEngine, and once set, the > > normal tasks within the subcgroup would not be able to overwrite it. This is > > enforced by promoting the permission of the color file in cgroupfs. > > Why can't the above work by setting 'tag' (that's a terrible name, why > does that still live) in CDE? Have the most specific tag live. Same with > that thread stuff. > > All this API stuff here is a complete and utter trainwreck. Please just > delete the patches and start over. Hint: if you use stop_machine(), > you're doing it wrong. > > At best you now have the requirements sorted. +1, just remove this patch from the series so as to unblock the series. Balbir Singh.