From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: cgroups(7): documenting /sys/kernel/cgroup files Date: Wed, 10 Jan 2018 20:14:20 +0100 Message-ID: <16c30b5d-d2c6-ffb0-9374-f48cb3bc154a@gmail.com> References: <20180110124407.GA26913@castle.DHCP.thefacebook.com> <20180110140239.GX3668920@devbig577.frc2.facebook.com> <20180110174457.GI3668920@devbig577.frc2.facebook.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=cc:subject:to:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=nTp/e8Qz2k/kTevGoHkl8Wc/HhedqFcsfFX9JiSOFJI=; b=R6NvBkmcY+CRbpBq7DmHP5arCbXKrVrQhPHN3LpD6aOuLzXrIlRYzUXTWLVkxjteru 6bRdwj/+czVGcNY1WMM12yr6e55zjCQ8po/m/NsXm01IcjjABjozz3ZpcXLqZc8qHSg2 H2bhzbX6AzKsTgtWEATOkwRwvyvF4/af0Ueb6xz8J/A/lwANsfFuUk9/lwizBsc9EeWN 4oV/1YWpeLIzWsSeTRVnIP5puCSaSYCCF2bmfPZ4JuhfFZy3OGnWr5d/KoCX794SI9i6 shr/veVtTGEo+hJqGi8Qzes5ECzpX36qju5lPerdNKLcah0N5mM/JO7jAHeIUwYfzFac FVJA== In-Reply-To: <20180110174457.GI3668920-4dN5La/x3IkLX0oZNxdnEQ2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org> Content-Language: en-US Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo , Roman Gushchin Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, "Serge E. Hallyn" , linux-man , lkml , "open list:CONTROL GROUP (CGROUP)" On 01/10/2018 06:44 PM, Tejun Heo wrote: > On Wed, Jan 10, 2018 at 06:02:39AM -0800, 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. > > Please disregard. > > Just like we can't mark the root cgroup threaded, we can't mark > delegated subtree root's threaded, so cgroup.type is not delegatable. > > However, the delegated root's children can definitely be marked > threadaed and they will join the delegated root's domain and the > threads are free to move between root and the threaded subtree. Exactly, so cgroup.threads in the threaded root must be made writable by the delegatee. Thanks, Tejun. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/