From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH 0/4] Netfilter ingress support (v3) Date: Tue, 5 May 2015 00:21:31 +0200 Message-ID: <20150504222131.GA4348@salvia> References: <1430736649-3546-1-git-send-email-pablo@netfilter.org> <20150504155639.GA14367@Alexeis-MBP.westell.com> <20150504161956.GK22481@breakpoint.cc> <5547AA9C.3030300@mojatatu.com> <20150504174358.GN22481@breakpoint.cc> <5547BEC4.4090400@mojatatu.com> <20150504185941.GA17061@breakpoint.cc> <20150504200506.GA14604@Alexeis-MacBook-Pro.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Florian Westphal , Jamal Hadi Salim , netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, kaber@trash.net To: Alexei Starovoitov Return-path: Received: from mail.us.es ([193.147.175.20]:43332 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbbEDWQ5 (ORCPT ); Mon, 4 May 2015 18:16:57 -0400 Content-Disposition: inline In-Reply-To: <20150504200506.GA14604@Alexeis-MacBook-Pro.local> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Mon, May 04, 2015 at 01:05:08PM -0700, Alexei Starovoitov wrote: > [...] TC critical path becomes slower with extra dereference and > indirect jump. You complained on the performance impact of the initial generic hook infrastructure that allows qdisc ingress and nft to co-exist, fair enough. I came back with an even more simple hook infrastructure, to address performance concerns, and you indicate that an *extra dereference and indirect jump* makes this slowier and that both cannot co-exist with this. Well, any kind of hook generalization will need at least those minimal changes. And that allows us to move code that belongs to sch_ingress. That got embedded into net/core/dev.c because at the time this code was made when there was no RCU around. This sounds as an excuse to me.