linux-kernel - Re: [PATCH v2 net-next 2/4] net: switchdev: add support for offloading of fdb locked flag

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Message-ID: <20220324110959.t4hqale35qbrakdu@skbuf>
Date:   Thu, 24 Mar 2022 13:09:59 +0200
From:   Vladimir Oltean <olteanv@...il.com>
To:     Hans Schultz <schultz.hans@...il.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Ivan Vecera <ivecera@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Shuah Khan <shuah@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Ido Schimmel <idosch@...dia.com>, linux-kernel@...r.kernel.org,
        bridge@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 net-next 2/4] net: switchdev: add support for
 offloading of fdb locked flag

On Thu, Mar 24, 2022 at 11:32:08AM +0100, Hans Schultz wrote:
> On ons, mar 23, 2022 at 16:43, Vladimir Oltean <olteanv@...il.com> wrote:
> > On Wed, Mar 23, 2022 at 01:49:32PM +0100, Hans Schultz wrote:
> >> >> Does someone have an idea why there at this point is no option to add a
> >> >> dynamic fdb entry?
> >> >> 
> >> >> The fdb added entries here do not age out, while the ATU entries do
> >> >> (after 5 min), resulting in unsynced ATU vs fdb.
> >> >
> >> > I think the expectation is to use br_fdb_external_learn_del() if the
> >> > externally learned entry expires. The bridge should not age by itself
> >> > FDB entries learned externally.
> >> >
> >> 
> >> It seems to me that something is missing then?
> >> My tests using trafgen that I gave a report on to Lunn generated massive
> >> amounts of fdb entries, but after a while the ATU was clean and the fdb
> >> was still full of random entries...
> >
> > I'm no longer sure where you are, sorry..
> > I think we discussed that you need to enable ATU age interrupts in order
> > to keep the ATU in sync with the bridge FDB? Which means either to
> > delete the locked FDB entries from the bridge when they age out in the
> > ATU, or to keep refreshing locked ATU entries.
> > So it seems that you're doing neither of those 2 things if you end up
> > with bridge FDB entries which are no longer in the ATU.
> 
> Any idea why G2 offset 5 ATUAgeIntEn (bit 10) is set? There is no define
> for it, so I assume it is something default?

No idea, but I can confirm that the out-of-reset value I see for
MV88E6XXX_G2_SWITCH_MGMT on 6190 and 6390 is 0x400. It's best not to
rely on any reset defaults though.