Re: [RFC][PATCH 0/5] uts namespaces: Introduction

[ebiederm@xmission.com (Eric W. Biederman)]

"Serge E. Hallyn" <serue@us.ibm.com> writes:

> Introduce utsname namespaces.  Instead of a single system_utsname
> containing hostname domainname etc, a process can request it's
> copy of the uts info to be cloned.  The data will be copied from
> it's original, but any further changes will not be seen by processes
> which are not it's children, and vice versa.
>
> This is useful, for instance, for vserver/openvz, which can now clone
> a new uts namespace for each new virtual server.
>
> This patchset is based on Kirill Korotaev's Mar 24 submission, taking
> comments (in particular from James Morris and Eric Biederman) into
> account.
>
> Some performance results are attached.  I was mainly curious whether
> it would be worth putting the task_struct->uts_ns pointer inside
> a #ifdef CONFIG_UTS_NS.  The result show that leaving it in when
> CONFIG_UTS_NS=n has negligable performance impact, so that is the
> approach this patch takes.

Ok.  This looks like the best version so far.

I like the utsname() function thing to shorten the 
idiom of  current->uts_ns->name.

We probably want to introduce utsname() and an init_utsname()
before any of the other changes, and then perform the substitutions,
before we actually change the code so the patchset can make it
through a git-bisect.  This will also allows for something
that can be put in compat-mac.h for backports of anything that
cares.

Eric