Re: [PATCH -mm] remove node_ prefix_from ns subsystem

Andrew Morton
2008-05-22T08:37:57Z

On Thu, 22 May 2008 01:23:35 -0700 "Paul Menage" <menage@google.com> wrote:

> Hi Andrew,
>
> On Thu, May 22, 2008 at 1:10 AM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
> >
> > What the change is, why it is being made, what the user-visible
> > presentation is, what the impact upon users is, why we think it won't
> > be a problem, etc? The stuff which should have been right there from
> > day one, before the code change was even made?
>
> The change is that previously when cgroup_clone() was called
> (currently only from the unshare path in ns_proxy cgroup, you'd get a
> new group named "node_$pid" whereas now you'll get a group named after
> just your pid.)
>
> The only users who would notice it are those who are using the
> ns_proxy cgroup subsystem to auto-create cgroups when namespaces are
> unshared - something of an experimental feature, which I think really
> needs more complete container/namespace support in order to be useful.
> I suspect the only users are Cedric and Serge, or maybe a few others
> on containers@lists.linux-foundation.org. And in fact it would only be
> noticed by the users who make the assumption about how the name is
> generated, rather than getting it from the /proc/<pid>/cgroups file
> for the process in question.
>
> Whether the change is actually needed or not I'm fairly agnostic on,
> but I guess it is more elegant to just use the pid as the new group
> name rather than adding a fairly arbitrary "node_" prefix on the
> front.
>

Well I suppose that as a non-back-compatible change we should feed it
into 2.6.25.x as well. It's a bit unusual, but so doing will reduce the
number of hey-where-did-my-file-go discoveries.