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Message-ID: <6599ad830702201536t7df92965pba0eb4f147742d12@mail.gmail.com>
Date: Tue, 20 Feb 2007 15:36:18 -0800
From: "Paul Menage" <menage@google.com>
To: "Sam Vilain" <sam@vilain.net>
Subject: Re: [PATCH 0/7] containers (V7): Generic Process Containers
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, akpm@osdl.org, pj@sgi.com,
       sekharan@us.ibm.com, dev@sw.ru, xemul@sw.ru, serue@us.ibm.com,
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On 2/20/07, Sam Vilain <sam@vilain.net> wrote:
> Paul Menage wrote:
> >> No. A reverse mapping is not needed and is not interesting.
> >>
> > ... to you.
> >
>
> You're missing the point of Eric's next sentence.  If you can achieve
> everything you need to achieve and get all the information you are after
> without it, then it is uninteresting.

Yes, you can do it with an exhaustive trawl of /proc. That can be very
expensive on busy machines.

>
> >> As long as I can walk all processes and ask what namespace are
> >> you in I don't care.
> >>
> >
> > How do you currently do that?
> >
>
> Take a look at /proc/PID/mounts for example.

That doesn't tell you what mounts namespace a process is in - it tells
you what the process can *view* in the namespace.

>
> So make helpers.  Macros.  Anything, just don't introduce model
> limitations like the container structure, because we've already got the
> structure; the nsproxy.
>

As I mentioned in another email, nsproxy is fine for things that don't
need explicit configuration or reporting, or which already have
configuration methods (such as fork(), mount(), etc) available, and
which don't need to support movement of processes between different
"namespaces". If it was extended to support the
naming/config/movement, then it would be fine to use it as the
equivalent of a container.

I'd actually be interested in trying to combine my container object
and the nsproxy object into a single concept.

Paul
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