From: Aleksa Sarai <asarai-l3A5Bk7waGM@public.gmane.org>
To: James Bottomley
<James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>,
Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
Aleksa Sarai <cyphar-gVpy/LI/lHzQT0dZR+AlfA@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dev-IGmTWi+3HBZvNhPySn5qfx2eb7JE58TQ@public.gmane.org
Subject: Re: [PATCH v4 0/2] cgroup: allow management of subtrees by new cgroup namespaces
Date: Sat, 21 May 2016 02:29:55 +1000 [thread overview]
Message-ID: <573F3B83.3020206@suse.de> (raw)
In-Reply-To: <1463761509.8091.19.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
>> This is stemming from the fact that an unpriv application can't
>> create its sub-cgroups without explicit delegation from the root and
>> that has always been an explicit design choice.
>> It's tied to who's responsible for cleanup afterwards and what
>> happens when the process gets migrated to a different cgroup. The
>> latter is an important issue on v1 hierarchies because migrating
>> tasks sometimes is used as a way to control resource distribution.
>
> OK, so is the only problem cleanup? If so, what if I proposed that a
> cgroup directory could only be created by the owner of the userns
> (which would be any old unprivileged user) iff they create a cgroup ns
> and the cgroup ns would be responsible for removing it again, so the
> cgroup subdirectory would be tied to the cgroup namespace as its holder
> and we'd use release of the cgroup to remove all the directories?
The only question I'd have is how would we deal with visibility (and
should a "parent" cgroup namespace be able to modify things inside the
cgroup?). And of course, how would that interact with VFS?
--
Aleksa Sarai
Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/
WARNING: multiple messages have this Message-ID (diff)
From: Aleksa Sarai <asarai@suse.de>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Aleksa Sarai <cyphar@cyphar.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
dev@opencontainers.org
Subject: Re: [PATCH v4 0/2] cgroup: allow management of subtrees by new cgroup namespaces
Date: Sat, 21 May 2016 02:29:55 +1000 [thread overview]
Message-ID: <573F3B83.3020206@suse.de> (raw)
In-Reply-To: <1463761509.8091.19.camel@HansenPartnership.com>
>> This is stemming from the fact that an unpriv application can't
>> create its sub-cgroups without explicit delegation from the root and
>> that has always been an explicit design choice.
>> It's tied to who's responsible for cleanup afterwards and what
>> happens when the process gets migrated to a different cgroup. The
>> latter is an important issue on v1 hierarchies because migrating
>> tasks sometimes is used as a way to control resource distribution.
>
> OK, so is the only problem cleanup? If so, what if I proposed that a
> cgroup directory could only be created by the owner of the userns
> (which would be any old unprivileged user) iff they create a cgroup ns
> and the cgroup ns would be responsible for removing it again, so the
> cgroup subdirectory would be tied to the cgroup namespace as its holder
> and we'd use release of the cgroup to remove all the directories?
The only question I'd have is how would we deal with visibility (and
should a "parent" cgroup namespace be able to modify things inside the
cgroup?). And of course, how would that interact with VFS?
--
Aleksa Sarai
Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/
next prev parent reply other threads:[~2016-05-20 16:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-14 3:19 [PATCH v4 0/2] cgroup: allow management of subtrees by new cgroup namespaces Aleksa Sarai
2016-05-14 3:19 ` Aleksa Sarai
2016-05-14 3:19 ` [PATCH v4 1/2] cgroup: make cgroup.procs permissions userns-aware Aleksa Sarai
[not found] ` <1463196000-13900-1-git-send-email-asarai-l3A5Bk7waGM@public.gmane.org>
2016-05-14 3:20 ` [PATCH v4 2/2] cgroup: implement subtree creation on copy_cgroup_ns() Aleksa Sarai
2016-05-14 3:20 ` Aleksa Sarai
2016-05-20 14:48 ` [PATCH v4 0/2] cgroup: allow management of subtrees by new cgroup namespaces Aleksa Sarai
2016-05-20 14:48 ` Aleksa Sarai
[not found] ` <573F23D0.2030500-l3A5Bk7waGM@public.gmane.org>
2016-05-20 15:22 ` Tejun Heo
2016-05-20 15:22 ` Tejun Heo
[not found] ` <20160520152244.GB5632-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2016-05-20 15:30 ` James Bottomley
2016-05-20 15:30 ` James Bottomley
[not found] ` <1463758258.8091.3.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-05-20 16:03 ` Tejun Heo
2016-05-20 16:03 ` Tejun Heo
2016-05-20 16:09 ` James Bottomley
2016-05-20 16:17 ` Tejun Heo
[not found] ` <20160520161759.GD5632-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2016-05-20 16:25 ` James Bottomley
2016-05-20 16:25 ` James Bottomley
[not found] ` <1463761509.8091.19.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-05-20 16:29 ` Aleksa Sarai [this message]
2016-05-20 16:29 ` Aleksa Sarai
2016-05-20 16:53 ` Tejun Heo
[not found] ` <20160520165326.GE5632-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2016-05-20 17:28 ` James Bottomley
2016-05-20 17:28 ` James Bottomley
[not found] ` <1463765326.8091.42.camel-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>
2016-05-20 17:49 ` Tejun Heo
2016-05-20 17:49 ` Tejun Heo
2016-05-28 5:12 ` Aleksa Sarai
2016-05-31 18:18 ` Tejun Heo
2016-05-20 17:33 ` W. Trevor King
2016-05-20 17:33 ` W. Trevor King
2016-05-20 17:33 ` Aditya Kali
2016-05-20 17:50 ` James Bottomley
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