Re: [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY into userspace child

[Oleg Nesterov <oleg@redhat.com>]

On 11/28, Peter Zijlstra wrote:
>
> On Thu, Nov 28, 2013 at 04:34:43PM +0100, Oleg Nesterov wrote:
> > But note that in the longer term we might want even more. We probably
> > want a non-daemonized thread controlled by the user-space. And even
> > more, this thread should be per-namespace (this needs a lot more
> > discussion).
>
> Which namespace? PID namespace I presume where we can have a 'new' init
> task and everything.
>
> I'm not sure, are any of these things (workqueues, userspace helpers)
> pid namespace aware? If not it doesn't seem to make sense to expose this
> to nested PID namespaces and would be something special for the root
> namespace.

Not sure I understand correctly. But yes, of course, it is not that
call_usermodehelper() should be namespace-friendly "unconditionally".

We need another API (although perhaps we can simply add UMH_NAMESPACE
flag, this doesn't matter).

Just for example, the piped core handler. Currently it is hardly useful
in containers.

> > But whataver we do later, I believe that the patch from Zhang should
> > be applied now.
>
> Probably, although with a much adjusted changelog.

Zhang, please make v3 ;)

Oleg.