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

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Message-ID: <20160920003236.GD6323@lunn.ch>
Date:   Tue, 20 Sep 2016 02:32:36 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...oirfairelinux.com,
        "David S. Miller" <davem@...emloft.net>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: Re: [PATCH net-next] net: dsa: mv88e6xxx: handle multiple ports in
 ATU

On Mon, Sep 19, 2016 at 08:29:40PM -0400, Vivien Didelot wrote:
> Hi Andrew,
> 
> Andrew Lunn <andrew@...n.ch> 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