From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yang, Yi" Subject: Re: [PATCH net-next v9] openvswitch: enable NSH support Date: Wed, 27 Sep 2017 09:39:09 +0800 Message-ID: <20170927013908.GA33716@localhost.localdomain> References: <1506348969-6233-1-git-send-email-yi.y.yang@intel.com> <20170925201439.08460295@griffin> <20170926045538.GA5896@localhost.localdomain> <20170926124914.60101ca1@griffin> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "netdev@vger.kernel.org" , "dev@openvswitch.org" , "e@erig.me" , "davem@davemloft.net" , Pravin Shelar , jan.scheurich@ericsson.com To: Jiri Benc Return-path: Received: from mga09.intel.com ([134.134.136.24]:58818 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033022AbdI0BnZ (ORCPT ); Tue, 26 Sep 2017 21:43:25 -0400 Content-Disposition: inline In-Reply-To: <20170926124914.60101ca1@griffin> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Sep 26, 2017 at 06:49:14PM +0800, Jiri Benc wrote: > On Tue, 26 Sep 2017 12:55:39 +0800, Yang, Yi wrote: > > After push_nsh, the packet won't be recirculated to flow pipeline, so > > key->eth.type must be set explicitly here, but for pop_nsh, the packet > > will be recirculated to flow pipeline, it will be reparsed, so > > key->eth.type will be set in packet parse function, we needn't handle it > > in pop_nsh. > > This seems to be a very different approach than what we currently have. > Looking at the code, the requirement after "destructive" actions such > as pushing or popping headers is to recirculate. This is optimization proposed by Jan Scheurich, recurculating after push_nsh will impact on performance, recurculating after pop_nsh is unavoidable, So also cc jan.scheurich@ericsson.com. Actucally all the keys before push_nsh are still there after push_nsh, push_nsh has updated all the nsh keys, so recirculating remains avoidable. > > Setting key->eth.type to satisfy conditions in the output path without > updating the rest of the key looks very hacky and fragile to me. There > might be other conditions and dependencies that are not obvious. > I don't think the code was written with such code path in mind. > > I'd like to hear what Pravin thinks about this. > > Jiri