From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752453AbcGRUNi (ORCPT ); Mon, 18 Jul 2016 16:13:38 -0400 Received: from vps0.lunn.ch ([178.209.37.122]:45015 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbcGRUNh (ORCPT ); Mon, 18 Jul 2016 16:13:37 -0400 Date: Mon, 18 Jul 2016 22:13:34 +0200 From: Andrew Lunn To: Vivien Didelot Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@savoirfairelinux.com, "David S. Miller" , Florian Fainelli Subject: Re: [PATCH v2 net-next v2 12/12] net: dsa: mv88e6xxx: add support for DSA ageing time Message-ID: <20160718201334.GS31103@lunn.ch> References: <20160718184628.13103-1-vivien.didelot@savoirfairelinux.com> <20160718184628.13103-13-vivien.didelot@savoirfairelinux.com> <20160718191644.GG31103@lunn.ch> <87d1malpcd.fsf@ketchup.mtl.sfl> <20160718193253.GJ31103@lunn.ch> <87eg6q3efp.fsf@ketchup.mtl.sfl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87eg6q3efp.fsf@ketchup.mtl.sfl> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 18, 2016 at 03:59:38PM -0400, Vivien Didelot wrote: > Andrew Lunn writes: > > >> Nope, the bridge ageing time is not per-port, even though switchdev ops > >> are per-port by design. This is a switch-wide attribute. > > > > So you are saying the core is doing all the reference counting, etc, > > when swapping between fast and slow ageing? > > I don't see how checking for the fastest ageing time would fix support > for multiple bridges... The bridge should switch to fast ageing after a topology change to flush out entries which are now wrong. Using the short age time for too long results in a bit more inefficiency, in that entries time out faster than they need to. But if we go back to slow ageing too quickly, e.g. because of another bridge, we get wrong operation, in that bad entries can get stuck in the table for up to 5 minutes. So either we need to keep fast ageing as long as there is one bridge fast ageing, or we need to flush the whole MAC cache for a bridge on topology change and don't bother with fast ageing at all. > Maybe we can keep it simple for the moment with this switch-wide > set_ageing_time operation, and later add a patch for the DSA layer to > cache and elect the ageing time per-port or per-bridge. I don't think it can be done at the DSA layer. It does not have the information needed. Andrew