Re: [RFC PATCH net-next] net: Add l3mdev cgroup

[David Ahern <dsa-qUQiAmfTcIp+XZJcv9eMoEEOCMrvLtNR@public.gmane.org>]

On 1/4/16 11:59 AM, Tejun Heo wrote:
> Hello, David.
>
> On Mon, Jan 04, 2016 at 11:53:55AM -0700, David Ahern wrote:
>> On 1/4/16 10:58 AM, Tejun Heo wrote:
>>> Please don't create any new controller whose sole purpose is
>>> identifying group membership.  Please take a look at how libxt_cgroup
>>> handles identification w/o creating a new controller.
>>>
>>>   http://lkml.kernel.org/g/1449527935-27056-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
>>>
>>
>> This controller applies a cgroup specific setting to tasks associated with
>> an instance (similar to cpuset restricting tasks to specifics CPUs), so it
>> is more than just identifying membership.
>
> Any identification can be mapped back and forth to setting configs to
> a set of tasks.  That doesn't change the fact that all the controller
> is doing is identifying cgroup membership and the proposed controller
> shares exatly the same problems as netprio or netcls controllers.
>
>> I looked at the commits referenced above and net/netfilter/xt_cgroup.c code
>> in particular and I don't see how it applies to this use case. Can you
>> elaborate?
>
> Match cgroup membership in whatever subsystem that cares about it and
> apply the policy there.
>

None of the existing subsystems are relevant for configuring an L3 
networking domain, and it does not make sense to tie net_cls and 
net_prio to an L3 domain.