From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH net] geneve: initialize needed_headroom Date: Wed, 23 Dec 2015 16:35:13 +0100 Message-ID: <567ABF31.8080306@stressinduktion.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Pravin B Shelar , Jiri Benc , Jesse Gross To: Paolo Abeni , netdev@vger.kernel.org Return-path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:58972 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbbLWPfQ (ORCPT ); Wed, 23 Dec 2015 10:35:16 -0500 Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailout.nyi.internal (Postfix) with ESMTP id 204F120D09 for ; Wed, 23 Dec 2015 10:35:15 -0500 (EST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 23.12.2015 16:21, Paolo Abeni wrote: > Currently the needed_headroom field for the geneve device is left > to the default value. > > This patch set it to space required for basic geneve encapsulation, > so that we can avoid the skb head re-allocation on xmit. > > This give a 6% speedup for unsegment traffic on geneve tunnel. > > Signed-off-by: Paolo Abeni > Acked-by: Hannes Frederic Sowa (Sorry, just saw this.) > --- > drivers/net/geneve.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c > index c2b79f5..bb3e6ed 100644 > --- a/drivers/net/geneve.c > +++ b/drivers/net/geneve.c > @@ -1155,7 +1155,7 @@ static int geneve_configure(struct net *net, struct net_device *dev, > struct geneve_net *gn = net_generic(net, geneve_net_id); > struct geneve_dev *t, *geneve = netdev_priv(dev); > bool tun_collect_md, tun_on_same_port; > - int err; > + int err, encap_len; > > if (!remote) > return -EINVAL; > @@ -1187,6 +1187,14 @@ static int geneve_configure(struct net *net, struct net_device *dev, > if (t) > return -EBUSY; > > + /* make enough headroom for basic scenario */ > + encap_len = GENEVE_BASE_HLEN + ETH_HLEN; > + if (remote->sa.sa_family == AF_INET) > + encap_len += sizeof(struct iphdr); > + else > + encap_len += sizeof(struct ipv6hdr); > + dev->needed_headroom = encap_len; > + We are missing one time ETH_HLEN or hard_header_len of the lower_dev (if available) in here AFAIK. Thanks, Hannes