From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 3/4 v2 net-next] net: make GRO aware of skb->head_frag Date: Mon, 30 Apr 2012 21:48:31 -0400 (EDT) Message-ID: <20120430.214831.1079448543357914010.davem@davemloft.net> References: <1335523026.2775.236.camel@edumazet-glaptop> <1335809434.2296.9.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, ncardwell@google.com, therbert@google.com, jeffrey.t.kirsher@intel.com, mchan@broadcom.com, mcarlson@broadcom.com, herbert@gondor.hengli.com.au, bhutchings@solarflare.com, ilpo.jarvinen@helsinki.fi, maze@google.com To: eric.dumazet@gmail.com Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:44949 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757762Ab2EABst (ORCPT ); Mon, 30 Apr 2012 21:48:49 -0400 In-Reply-To: <1335809434.2296.9.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Mon, 30 Apr 2012 20:10:34 +0200 > From: Eric Dumazet > > GRO can check if skb to be merged has its skb->head mapped to a page > fragment, instead of a kmalloc() area. > > We 'upgrade' skb->head as a fragment in itself > > This avoids the frag_list fallback, and permits to build true GRO skb > (one sk_buff and up to 16 fragments), using less memory. > > This reduces number of cache misses when user makes its copy, since a > single sk_buff is fetched. > > This is a followup of patch "net: allow skb->head to be a page fragment" > > Signed-off-by: Eric Dumazet Applied.