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 [off-list ref]

Thanks.

-- 
tejun

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