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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 4ED46ECDFB8 for ; Fri, 20 Jul 2018 15:45:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 013E720661 for ; Fri, 20 Jul 2018 15:45:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ZDkXng6i" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 013E720661 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387784AbeGTQeG (ORCPT ); Fri, 20 Jul 2018 12:34:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:40102 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731583AbeGTQeG (ORCPT ); Fri, 20 Jul 2018 12:34:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=CTrgbzCEKwqwIlnAuzvzAfy7hiCeZtkIp3hlVKFAupY=; b=ZDkXng6iPrf7HgV0QmP6nbYJZ iepEUF6kOnr6mFNCo5Rd5SuQb2txNi/aPqt3Al2wttST8EAwOA/ClV6akx5jFIfu3qp/1RejfCf+u jjMq2z7TQQOQG05F47AQQtLOc71uyHpEdV7AitHRuCCx0U8jnBEBNRwGvC0XUc0g/OCMXe2pgFALw ZKsWMEpmR8nXpDCyaq6mJ4cvAMzJxzmjMzGIhgNmHziQfbOMPL7OUPTopKK1uSaJh8H/2RDIVzNp3 jh273DMC6davrkmmBvfNAgZ4L4JIfKXEO8qXnG6ddf5NrXzwrtHsJfWu7+r39njbXElf/5oJU2LDk 6Q5x2bmiQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fgXaS-0006CY-SX; Fri, 20 Jul 2018 15:44:57 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 0C9DE20275F37; Fri, 20 Jul 2018 17:44:54 +0200 (CEST) Date: Fri, 20 Jul 2018 17:44:54 +0200 From: Peter Zijlstra To: Tejun Heo Cc: Waiman Long , Li Zefan , Johannes Weiner , Ingo Molnar , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, Mike Galbraith , torvalds@linux-foundation.org, Roman Gushchin , Juri Lelli , Patrick Bellasi Subject: Re: [PATCH v11 7/9] cpuset: Expose cpus.effective and mems.effective on cgroup v2 root Message-ID: <20180720154454.GR2494@hirez.programming.kicks-ass.net> References: <20180702165322.GI533219@devbig577.frc2.facebook.com> <20180703155823.GS533219@devbig577.frc2.facebook.com> <20180719135224.GE2494@hirez.programming.kicks-ass.net> <1107494a-9667-df58-dcac-9366e969dc3a@redhat.com> <20180719153045.GT72677@devbig577.frc2.facebook.com> <20180719165201.GU72677@devbig577.frc2.facebook.com> <20180720113121.GJ2476@hirez.programming.kicks-ass.net> <20180720114549.GY72677@devbig577.frc2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180720114549.GY72677@devbig577.frc2.facebook.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 20, 2018 at 04:45:49AM -0700, Tejun Heo wrote: > > > Hmm... so a given ancestor must be able to both > > > > > > 1. control which cpus are moved into a partition in all of its > > > subtree. > > > > By virtue of the partition file being owned by the parent, this is > > already achived, no? > > The currently proposed implementation is somewhere in the middle. It > kinda gets there by restricting a partition to be a child of another > partition, which may be okay but it does make the whole delegation > mechanism less useful. So the implementation does not set ownership of the 'partition' file to that of the parent directory? Because _that_ is what I understood from Waiman (many versions ago). And that _does_ allow delegation to work nicely. > > > 2. take away any given cpu from ist subtree. > > > > I really hate this obsession of yours and doubly so for partitions. But > > why would this currently not be allowed? > > Well, sorry that you hate it. It's a fundamental architectural > constraint. If it can't satisfy that, it should't be in cgroup. So is hierarchical behaviour; but you seem willing to forgo that. Still, the question was, how is this (dispicable or not) behaviour not allowed by the current implementation?