[Devel] Re: [PATCH 07/11] mm: Allocate kernel pages to the right memcg

[Glauber Costa]

On 06/25/2012 10:07 PM, Tejun Heo wrote:
> On Mon, Jun 25, 2012 at 06:15:24PM +0400, Glauber Costa wrote:
>> When a process tries to allocate a page with the __GFP_KMEMCG flag,
>> the page allocator will call the corresponding memcg functions to
>> validate the allocation. Tasks in the root memcg can always proceed.
>>
>> To avoid adding markers to the page - and a kmem flag that would
>> necessarily follow, as much as doing page_cgroup lookups for no
>> reason, whoever is marking its allocations with __GFP_KMEMCG flag
>> is responsible for telling the page allocator that this is such an
>> allocation at free_pages() time. This is done by the invocation of
>> __free_accounted_pages() and free_accounted_pages().
>
> Shouldn't we be documenting that in the code somewhere, preferably in
> the function comments?
>
I can certainly do that.