Re: [PATCH 1/3] change clone_flags type to u64

["Serge E. Hallyn" <serue@us.ibm.com>]

Quoting Andi Kleen (andi@firstfloor.org):
> > I guess that was a development rationale. 
> 
> But what rationale? It just doesn't make much sense to me.
> 
> > Most of the namespaces are in 
> > use in the container projects like openvz, vserver and probably others 
> > and we needed a way to activate the code.
> 
> You could just have added it to feature groups over time.
> 
> > 
> > Not perfect I agree.
> >  
> > > With your current strategy are you sure that even 64bit will
> > > be enough in the end? For me it rather looks like you'll
> > > go through those quickly too as more and more of the kernel
> > > is namespaced.
> > 
> > well, we're reaching the end. I hope ! devpts is in progress and
> > mq is just waiting for a clone flag.
> 
> Are you sure?

Well for one thing we can take a somewhat different approach to new
clone flags.  I.e. we could extend CLONE_NEWIPC to do mq instead of
introducing a new clone flag.  The name doesn't have 'sysv' in it,
and globbing all ipc resources together makes some amount of sense.
Similarly has hpa+eric pointed out earlier, suka could use
CLONE_NEWDEV for ptys.  If we have net, pid, ipc, devices, that's a
pretty reasonable split imo.  Perhaps we tie user to devices and get
rid of CLONE_NEWUSER which I suspect noone is using atm (since only
Dave has run into the CONFIG_USER_SCHED problem).  Or not.  We could
roll uts into net, and give CLONE_NEWUTS a deprecation period.

-serge