From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net-next 5/5] net: sctp: fix and consolidate SCTP checksumming code Date: Mon, 04 Nov 2013 22:10:16 +0100 Message-ID: <52780D38.9050807@redhat.com> References: <1383130252-1515-1-git-send-email-dborkman@redhat.com> <1383130252-1515-6-git-send-email-dborkman@redhat.com> <527117C3.2080306@gmail.com> <52778EF6.4000801@redhat.com> <5277C6E4.4010604@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-sctp@vger.kernel.org To: Vlad Yasevich Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63099 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749Ab3KDVeO (ORCPT ); Mon, 4 Nov 2013 16:34:14 -0500 In-Reply-To: <5277C6E4.4010604@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/04/2013 05:10 PM, Vlad Yasevich wrote: > On 11/04/2013 07:11 AM, Daniel Borkmann wrote: >> On 10/30/2013 03:29 PM, Vlad Yasevich wrote: >>> On 10/30/2013 06:50 AM, Daniel Borkmann wrote: >> [...] >>> Daniel >>> >>> Here is a follow-on idea that might help even more. >>> What if we put a pointer to skb_checksum_ops() in the skb >>> somewhere (I was thinking of skb_shinfo). Then >>> skb_checksum can simply use the data from there. This would >>> allow us to get rid of all the special cases in SCTP that do >>> checksumming. We can just set it to partial, set up the right >>> fields and let HW or SW always do the right thing. >> >> I need to think about this a bit. This would certainly have the >> negative side-effect of a higher skb->truesize usage and thus >> affecting memory accounting for everyone as we extend >> skb_shared_info. > > You are talking a single pointer here... The alternative > is to do a per-protocol table. Well, that is e.g. 8 more byte per skb, right? ;) I think if we need these kind of changes in many more places than currently, then this would make sense indeed.