[Devel] Re: [PATCH v5 06/14] memcg: kmem controller infrastructure

[David Rientjes]

On Thu, 18 Oct 2012, Glauber Costa wrote:

> > Do we actually need to test PF_KTHREAD when current->mm == NULL? 
> > Perhaps because of aio threads whcih temporarily adopt a userspace mm?
> 
> I believe so. I remember I discussed this in the past with David
> Rientjes and he advised me to test for both.
> 

PF_KTHREAD can do use_mm() to assume an ->mm but hopefully they aren't 
allocating slab while doing so.  Have you considered actually charging 
current->mm->owner for that memory, though, since the kthread will have 
freed the memory before unuse_mm() or otherwise have charged it on behalf 
of a user process, i.e. only exempting PF_KTHREAD?