Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752695AbeAJRcD (ORCPT + 1 other); Wed, 10 Jan 2018 12:32:03 -0500 Received: from mail-wm0-f51.google.com ([74.125.82.51]:46549 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751446AbeAJRbm (ORCPT ); Wed, 10 Jan 2018 12:31:42 -0500 X-Google-Smtp-Source: ACJfBov+t12QAz/IGUo80dG15zd+KBwpnaiobMhD9/UihX0pxjQJ2LjpGw5wokyUFFnBbpYX/r6TR8KQdWut6g/bsXI= MIME-Version: 1.0 Reply-To: mtk.manpages@gmail.com In-Reply-To: <20180110140239.GX3668920@devbig577.frc2.facebook.com> References: <20180110124407.GA26913@castle.DHCP.thefacebook.com> <20180110140239.GX3668920@devbig577.frc2.facebook.com> From: "Michael Kerrisk (man-pages)" Date: Wed, 10 Jan 2018 18:31:20 +0100 Message-ID: Subject: Re: cgroups(7): documenting /sys/kernel/cgroup files To: Tejun Heo Cc: Roman Gushchin , "Serge E. Hallyn" , linux-man , lkml , "open list:CONTROL GROUP (CGROUP)" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hello Tejun, On 10 January 2018 at 15:02, Tejun Heo wrote: > Hello, > > On Wed, Jan 10, 2018 at 04:44:14AM -0800, Roman Gushchin wrote: >> cgroup.threads is not listed because it's not delegatable (doesn't have >> CFTYPE_NS_DELEGATABLE flag set). I don't know if it was intended or just >> an accident (I believe the latter). > > So, thread mode isn't delegatble. Marking a cgroup as threaded turns > that subtree threaded and join the parent's domain, so we can't allow > delegation roots to be turned threaded - just like we can't mark the > root cgroup threaded, and I'm not really not sure what it means to > delegate a portion of threaded subtree. 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? Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/