lkml.org 
[lkml]   [2006]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC][PATCH 0/20] Multiple instances of the process id namespace
Eric W. Biederman wrote:
> There have been several discussions in the past month about how
> to do a good job of implementing a subset of user space that
> looks like it has the system to itself. Essentially making
> chroot everything it could be. This is my take on what
> the implementation of a pid namespace should look like.
>

Eric, this looks very good. The pspace internal implementation
is very similar to what I was working on objectifying the pidmap
etc. I was pursuing the same route in using find_pid()
functions as the means to distinguish pspaces rather then
actually virtualizing them.

But this code already goes so much further in many many aspects.
Kudos to you.
I am still going through some of the details, but this is an
excellent starting position.

>
> What follows is a real patch set that is sufficiently complete
> to be used and useful in it's own right. There are a few areas
> of the kernel where the patchset does not reach, mostly these
> cause the compile to fail. In addition a good thorough review
> still needs to be done. This patchset does paint a picture
> of how I think things should look.
>
> From the kernel community at large I am asking:
> Does the code look generally sane?

Yes, but I have one question for you...
Large parts of the patch are adding the pspace argument
to find_task_by_pid() and in many cases that argument is
current->pspace.
It might bring down the size of the patch if you
have

find_task_by_pid( pid ) { return find_task_pidspace_by_pid ( current->pspace, pid ); }

and then only deal with the exceptional cases using find_task_pidspace_by_pid
when the pidspace is different..

>
> Does the use of clone to create a new namespace instance look
> like the sane approach?
>

At he surface it looks OK .. how does this work in a multi-threaded
process which does cloen ( CLONE_NPSPACE ) ?
We discussed at some point that exec is the right place to do it,
but what I get is that because this is the container_init task
we are OK !
A bit clarification would help here ...

> Hopefully this code is sufficiently comprehensible to allow a good
> discussion to come out of this.
>

Yes

> Thanks for your time,
>
> Eric

-- Hubertus

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-02-06 21:44    [W:0.177 / U:3.196 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site