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

[Tejun Heo]

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?

-- 
tejun