Re: [BUGFIX][PATCH 3/3] memcg/tcp: ignore tcp usage before accounting started

[Glauber Costa <glommer@xxxxxxxxxxxxx>]

On 04/08/2012 09:58 PM, KAMEZAWA Hiroyuki wrote:
> (2012/04/04 7:31), Glauber Costa wrote:
>
> > On 04/02/2012 07:41 AM, David Miller wrote:
> > > From: Glauber Costa<glommer@xxxxxxxxxxxxx>
> > > Date: Thu, 29 Mar 2012 11:21:07 +0200
> > >
> > > > On 03/29/2012 09:10 AM, KAMEZAWA Hiroyuki wrote:
> > > > > tcp memcontrol starts accouting after res->limit is set. So, if a sockets
> > > > > starts before setting res->limit, there are already used resource.
> > > > > After setting res->limit, the resource (already used) will be uncharged and
> > > > > make res_counter below 0 because they are not charged. This causes warning.
> > > > >
> > > > > This patch fixes that by adding res_counter_uncharge_nowarn().
> > > > > (*) We cannot avoid this while we have 'account start' switch.
> > > > >
> > > > > Signed-off-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > > >
> > > > Fine by me.
> > > >
> > > > Acked-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
> > >
> > > I'm not applying patches that simply ignore accounting counter
> > > underflows.
> > >
> > > You must either:
> > >
> > > 1) Integrate the socket's existing usage when the limit is set.
> > >
> > > 2) Avoid accounting completely for a socket that started before
> > >      the limit was set.
> > >
> > > No half-way solutions, please.  Otherwise it is impossible to design
> > > validations of the resource usage for a particular socket or group of
> > > sockets, because they can always be potentially "wrong" and over the
> > > limit.  That's a design for a buggy system.
> > Kame,
> >
> > I agree with Dave FWIW.
> >
> > We should be able to do this by dropping the reference count when the
> > cgroup is finally destroyed, instead of from the remove callback. At
> > that point, no more pending sockets should be attached to it.
> >
> > Prior to increasing the static key, they are all assigned to the global
> > cgroup, so we shouldn't care about them.
>
> Could you do the fix ?
>
> Thanks,
> -Kame
I sent you a version already. Please just make sure it works for you

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html