Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751801AbeAJRjs (ORCPT + 1 other); Wed, 10 Jan 2018 12:39:48 -0500 Received: from mail-qt0-f179.google.com ([209.85.216.179]:42832 "EHLO mail-qt0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751002AbeAJRjq (ORCPT ); Wed, 10 Jan 2018 12:39:46 -0500 X-Google-Smtp-Source: ACJfBoucZ2OkuvzUAXh1RVTXPC4zvbg6Z12DCCt9IFoGvwvxzgVV/bkb2oHOPA22AS0yrG8qXDq0AA== Date: Wed, 10 Jan 2018 09:39:42 -0800 From: Tejun Heo To: "Michael Kerrisk (man-pages)" Cc: Roman Gushchin , "Serge E. Hallyn" , linux-man , lkml , "open list:CONTROL GROUP (CGROUP)" Subject: Re: cgroups(7): documenting /sys/kernel/cgroup files Message-ID: <20180110173942.GH3668920@devbig577.frc2.facebook.com> References: <20180110124407.GA26913@castle.DHCP.thefacebook.com> <20180110140239.GX3668920@devbig577.frc2.facebook.com> <20180110173340.GG3668920@devbig577.frc2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180110173340.GG3668920@devbig577.frc2.facebook.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hello, again. On Wed, Jan 10, 2018 at 09:33:40AM -0800, Tejun Heo wrote: > Hello, Michael. > > On Wed, Jan 10, 2018 at 06:31:20PM +0100, Michael Kerrisk (man-pages) wrote: > > So, I am confused. According to Documentation/cgroup-v2.txt, > > cgoup.threads is delegated: > > > > [[ > > Model of Delegation > > ~~~~~~~~~~~~~~~~~~~ > > > > A cgroup can be delegated in two ways. First, to a less privileged > > user by granting write access of the directory and its "cgroup.procs", > > "cgroup.threads" and "cgroup.subtree_control" files to the user. > > Second, if the "nsdelegate" mount option is set, automatically to a > > cgroup namespace on namespace creation. > > ]] > > > > So, is that a mistake in that text file? > > Yes, it is. I probably copy&pasted from an earlier version where we > were marking threaded domains instead of threaded roots. Will fix it > right away. Jesus christ, sorry. Roman and the document are right. * cgroup.type is not delegatble, marking it threaded makes the cgroup join the parent's domain. * cgroup.threads is delegatable, because marking the child cgroups as threaded make them join the subtree root, and the threads can be dispersed across the parent - the delegated root here - and the subtree of the child which is marked threaded. I'll apply Roman's patch. Sorry about the confusion. Thanks. -- tejun