Re: [PATCH] Deny external checkpoint unless frozen

["Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

Quoting Dave Hansen (dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org):
> On Mon, 2009-02-23 at 17:04 -0600, Serge E. Hallyn wrote:
> > Quoting Sukadev Bhattiprolu (sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org):
> > > 
> > > From: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> > > Date: Sat, 21 Feb 2009 11:17:07 -0800
> > > Subject: [PATCH] Deny external checkpoint unless task is frozen
> > > 
> > > Remove a 'FIXME' and ensure that the tasks we are checkpointing are
> > > frozen unless its a self-checkpoint.
> > > 
> > > Signed-off-by: Sukadev Bhattiprolu <sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> > 
> > Agreed.  I personally would like to just get rid of support
> > for t==current, but don't expect to get anywhere with that
> > argument :)
> 
> Along the lines of what Ingo has been asking for, do we need to expose
> this logic in some way?  Do we need a /proc/$$/checkpointable file which
> says, "I'm not checkpointable because I'm not frozen"?

I really like that.

> Or, is this just a core part of the API: you have to freeze before
> checkpointing?  As such, we'll never move to a place where we're not
> frozen when checkpointing, so we might as well not even track or expose
> it.  

the only way that would make sense is if sys_checkpoint went ahead
and frozen them all, right?

-serge