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

From: Glauber Costa
Date: Fri Oct 19 2012 - 05:10:39 EST


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.

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