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

[Glauber Costa]

On 10/19/2012 02:06 AM, David Rientjes wrote:
> 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?
> 
I always charge current->mm->owner.