[Devel] Re: [PATCH 06/11] memcg: kmem controller infrastructure

[David Rientjes]

On Wed, 27 Jun 2012, Glauber Costa wrote:

> > > Nothing, but I also don't see how to prevent that.
> > 
> > You can test for current->flags & PF_KTHREAD following the check for
> > in_interrupt() and return true, it's what you were trying to do with the
> > check for !current->mm.
> > 
> 
> am I right to believe that if not in interrupt context - already ruled out -
> and !(current->flags & PF_KTHREAD), I am guaranteed to have a mm context, and
> thus, don't need to test against it ?
> 

No, because an mm may have been detached in the exit path by running 
exit_mm().  We'd certainly hope that there are no slab allocations 
following that point, though, but you'd still need to test current->mm.