Re: [PATCH net-next] net: dsa: mv88e6xxx: handle multiple ports in ATU

From: Andrew Lunn
Date: Mon Sep 19 2016 - 20:32:44 EST


On Mon, Sep 19, 2016 at 08:29:40PM -0400, Vivien Didelot wrote:
> Hi Andrew,
>
> Andrew Lunn <andrew@xxxxxxx> writes:
>
> > Hi Vivien
> >
> >> + do {
> >> + err = _mv88e6xxx_atu_getnext(chip, fid, &next);
> >> + if (err)
> >> + return err;
> >> +
> >> + if (next.state == GLOBAL_ATU_DATA_STATE_UNUSED)
> >> + break;
> >> +
> >> + if (ether_addr_equal(next.mac, addr)) {
> >> + *entry = next;
> >> + return 0;
> >> + }
> >> + } while (!is_broadcast_ether_addr(next.mac));
> >
> > This is correct, but i wonder how well it scales? When we have a lot
> > of entries in the ATU, this is going to take time. At some point in
> > the future, we might want to keep a shadow copy of static entries of
> > the ATU in RAM. We then don't need to search for them.
>
> There won't be any issue about time here, because we are searching a
> precise FID.

Ah, i didn't realise you can do that. However, it makes sense, the
hardware needs to do it all the time when it receives a frame.

Andrew