Re: [PATCH v2] cgroup: memcg: net: do not associate sock with unrelated cgroup

From: Eric Dumazet
Date: Fri Feb 14 2020 - 18:12:44 EST


On Fri, Feb 14, 2020 at 2:48 PM Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:

>
> I think in the current code if the association is skipped at
> allocation time then the sock will remain unassociated for its
> lifetime.
>
> Maybe we can add the association in the later stages but it seems like
> it is not a simple task i.e. edbe69ef2c90f ("Revert "defer call to
> mem_cgroup_sk_alloc()"").

Half TCP sockets are passive, so this means that 50% of TCP sockets
won't be charged.
(the socket cloning always happens from BH context)

I think this deserves a comment in the changelog or documentation,
otherwise some people might think
using memcg will make them safe.