Re: [PATCH 0/2] resource control file system - aka containers on top of nsproxy!

Srivatsa Vaddagiri
2007-03-05T17:41:05Z

On Sat, Mar 03, 2007 at 01:22:44PM -0800, Paul Jackson wrote:
> I still can't claim to have my head around this, but what you write
> here, Herbert, writes here touches on what I suspect is a key
> difference between namespaces and resources that would make it
> impractical to accomplish both with a shared mechanism for aggregating
> tasks.

The way nsproxy is structured, its all pointers to actual namespace (or
in case of rcfs patch) resource objects. This lets namespaces objects be in a
flat hierarchy while resource objects are in tree-like hierarchy.
nsproxy itself doesnt decide any hierarchy. Its those objects pointed to
by nsproxy which can form different hierarchies. In fact the rcfs
patches allows such a combination afaics.

> > on every limit accounting or check? I think that
> > is quite a lot of overhead ...
>
> Do either of these dereferences require locks?

A rcu_read_lock() should be required, which is not that expensive.

--
Regards,
vatsa