Re: [dpdk-dev] [PATCH v2 7/7] net/mlx5: e-switch VXLAN rule cleanup routines

[Yongseok Koh <yskoh@mellanox.com>]

On Thu, Oct 25, 2018 at 01:32:23PM -0700, Slava Ovsiienko wrote:
> > -----Original Message-----
> > From: Yongseok Koh
> > Sent: Thursday, October 25, 2018 3:37
> > To: Slava Ovsiienko <viacheslavo@mellanox.com>
> > Cc: Shahaf Shuler <shahafs@mellanox.com>; dev@dpdk.org
> > Subject: Re: [PATCH v2 7/7] net/mlx5: e-switch VXLAN rule cleanup routines
> > 
> > On Mon, Oct 15, 2018 at 02:13:35PM +0000, Viacheslav Ovsiienko wrote:
> > > The last part of patchset contains the rule cleanup routines.
> > > These ones is the part of outer interface initialization at the moment
> > > of VXLAN VTEP attaching. These routines query the list of attached
> > > VXLAN devices, the list of local IP addresses with peer and link scope
> > > attribute and the list of permanent neigh rules, then all found
> > > abovementioned items on the specified outer device are flushed.
> > >
> > > Suggested-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
> > > Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> > > ---
[...]
> > > -4100,12 +4596,9 @@ static LIST_HEAD(, mlx5_flow_tcf_vtep)
> > >  		uint16_t pcnt;
> > >
> > >  		/* Not found, we should create the new attached VTEP. */
> > > -/*
> > > - * TODO: not implemented yet
> > > - * flow_tcf_encap_iface_cleanup(tcf, ifouter);
> > > - * flow_tcf_encap_local_cleanup(tcf, ifouter);
> > > - * flow_tcf_encap_neigh_cleanup(tcf, ifouter);
> > > - */
> > > +		flow_tcf_encap_iface_cleanup(tcf, ifouter);
> > > +		flow_tcf_encap_local_cleanup(tcf, ifouter);
> > > +		flow_tcf_encap_neigh_cleanup(tcf, ifouter);
> > 
> > I have a fundamental questioin. Why are these cleanups needed? If I read the
> > code correctly, it looks like cleaning up vtep, ip assginment and neigh entry
> > which are not created/set by PMD. The reason why we have to clean up
> > things is that PMD exclusively owns the interface (ifouter). Is my
> > understanding correct?
> 
> Because this is the most simple approach. I have no guess how
> to co-exist with unknown pre-created rules and how to get into account
> all their properties and side effects.
> 
> While debugging I see the situations when application crashes and
> leaves a "leftovers" as VXLAN devices, neigh and local rules. If we run application again -
> these leftovers were the sources of errors (EEXIST on rule creations and so on).

Okay, makes sense.
Thanks for clarification.

Yongseok