Re: [patch 07/11] mm, memcg: allow processes handling oom notifications to access reserves

Tejun Heo
2014-03-06T21:12:46Z

On Tue, Mar 04, 2014 at 07:59:29PM -0800, David Rientjes wrote:
> Now that a per-process flag is available, define it for processes that
> handle userspace oom notifications. This is an optimization to avoid
> mantaining a list of such processes attached to a memcg at any given time
> and iterating it at charge time.
>
> This flag gets set whenever a process has registered for an oom
> notification and is cleared whenever it unregisters.
>
> When memcg reclaim has failed to free any memory, it is necessary for
> userspace oom handlers to be able to dip into reserves to pagefault text,
> allocate kernel memory to read the "tasks" file, allocate heap, etc.
>
> System oom conditions are not addressed at this time, but the same per-
> process flag can be used in the page allocator to determine if access
> should be given to userspace oom handlers to per-zone memory reserves at
> a later time once there is consensus.
>
> Signed-off-by: David Rientjes <rientjes@google.com>

ntil consensus on the whole approach can be reached,

Nacked-by: Tejun Heo <tj@kernel.org>

Thanks.

--
tejun