Re: [PATCH 03/14] net: tcp_memcontrol: properly detect ancestor socket pressure

David Miller
2015-11-13T16:00:19Z

From: Johannes Weiner <hannes@cmpxchg.org>
Date: Thu, 12 Nov 2015 18:41:22 -0500

> When charging socket memory, the code currently checks only the local
> page counter for excess to determine whether the memcg is under socket
> pressure. But even if the local counter is fine, one of the ancestors
> could have breached its limit, which should also force this child to
> enter socket pressure. This currently doesn't happen.
>
> Fix this by using page_counter_try_charge() first. If that fails, it
> means that either the local counter or one of the ancestors are in
> excess of their limit, and the child should enter socket pressure.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: David S. Miller <davem@davemloft.net>