netdev - Re: [PATCH net-next 1/2] bridge: Add a limit on FDB entries

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Message-ID: <c05b5623-c096-162f-3a2d-db19ca760098@blackwall.org>
Date: Tue, 16 May 2023 13:47:47 +0300
From: Nikolay Aleksandrov <razor@...ckwall.org>
To: Vladimir Oltean <vladimir.oltean@....com>
Cc: Andrew Lunn <andrew@...n.ch>, Florian Fainelli <f.fainelli@...il.com>,
 Oleksij Rempel <linux@...pel-privat.de>,
 Johannes Nixdorf <jnixdorf-oss@....de>, netdev@...r.kernel.org,
 bridge@...ts.linux-foundation.org, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Roopa Prabhu <roopa@...dia.com>,
 Ido Schimmel <idosch@...dia.com>
Subject: Re: [PATCH net-next 1/2] bridge: Add a limit on FDB entries

On 16/05/2023 13:44, Vladimir Oltean wrote:
> On Tue, May 16, 2023 at 01:32:05PM +0300, Nikolay Aleksandrov wrote:
>> Let's take a step back, I wasn't suggesting we start with a full-fledged switchdev
>> implementation. :) I meant only to see if the minimum global limit implementation
>> suggested would suffice and would be able to later extend so switchdev can use and
>> potentially modify (e.g. drivers setting limits etc). We can start with a simple
>> support for limits and then extend accordingly. The important part here is to
>> not add any uAPI that can't be changed later which would impact future changes.
> 
> I guess adding a global per-bridge learning limit now makes sense and
> would not unreasonably hinder switchdev later on. The focus is on
> "learning limit" and not a limit to user-created entries as Johannes has
> currently done in v1. I don't necessarily see an urgent need for
> IFLA_BR_FDB_CUR_ENTRIES, given the fact that user space can dump the FDB
> and count what it needs, filtering for FDB types accordingly.

Having the current count is just a helper, if you have a high limit dumping the table
and counting might take awhile. Thanks for the feedback, then we'll polish and move
on with the set for a global limit.