From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next-2.6] net: pskb_expand_head() optimization Date: Mon, 20 Sep 2010 14:40:42 +0200 Message-ID: <1284986442.3420.307.camel@edumazet-laptop> References: <1283852248.2338.160.camel@edumazet-laptop> <20100910.125449.235704956.davem@davemloft.net> <20100911123140.GA1939@del.dom.local> <20100919.171725.245378386.davem@davemloft.net> <20100920072149.GA6353@ff.dom.local> <1284973320.3420.49.camel@edumazet-laptop> <20100920091425.GA8381@ff.dom.local> <20100920121232.GA9931@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev@vger.kernel.org To: Jarek Poplawski Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:51576 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755350Ab0ITMks (ORCPT ); Mon, 20 Sep 2010 08:40:48 -0400 Received: by wwj40 with SMTP id 40so1017wwj.1 for ; Mon, 20 Sep 2010 05:40:46 -0700 (PDT) In-Reply-To: <20100920121232.GA9931@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-ID: Le lundi 20 septembre 2010 =C3=A0 12:12 +0000, Jarek Poplawski a =C3=A9= crit : > Hmm... I probably misread your reasoning. So, if no real reason, > really, how about turning this NET_SKBUFF_DATA_USES_OFFSET on > unconditionally in net-next, until somebody spots the difference? Yes, but most developpers use 64bit kernels anyway, I suspect nobody will ever notice :( Here (with a typical config), here is the vmlinux size before and after this patch : $ size vmlinux.old text data bss dec hex filename 6061748 640208 7285056 13987012 d56cc4 vmlinux.old $ size vmlinux text data bss dec hex filename 6070420 640208 7285056 13995684 d58ea4 vmlinux Thats 8672 bytes of text increase. (1330326 instructions instead of 1328472 -> 1854 more instructions)