From patchwork Thu Nov 21 18:13:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Graf X-Patchwork-Id: 293216 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5AA252C0099 for ; Fri, 22 Nov 2013 05:14:13 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754980Ab3KUSOJ (ORCPT ); Thu, 21 Nov 2013 13:14:09 -0500 Received: from merlin.infradead.org ([205.233.59.134]:54639 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754896Ab3KUSOB (ORCPT ); Thu, 21 Nov 2013 13:14:01 -0500 Received: from 77-56-192-57.dclient.hispeed.ch ([77.56.192.57] helo=localhost.localdomain) by merlin.infradead.org with esmtpsa (Exim 4.80.1 #2 (Red Hat Linux)) id 1VjYlK-0002HD-Np; Thu, 21 Nov 2013 18:13:59 +0000 From: Thomas Graf To: jesse@nicira.com, davem@davemloft.net Cc: dev@openvswitch.org, netdev@vger.kernel.org, dborkman@redhat.com, ffusco@redhat.com, fleitner@redhat.com, eric.dumazet@gmail.com, bhutchings@solarflare.com Subject: [PATCH net-next 8/8] openvswitch: Use skb_zerocopy() for upcall Date: Thu, 21 Nov 2013 19:13:39 +0100 Message-Id: X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org See http://www.infradead.org/rpr.html Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Use of skb_zerocopy() can avoids the expensive call to memcpy() when copying the packet data into the Netlink skb. Completes checksum through skb_checksum_help() if needed. Zerocopy is only performed if user space supported unaligned Netlink messages. memory mapped netlink i/o is preferred over zerocopy if it is set up. Cost of upcall is significantly reduced from: + 7.48% vhost-8471 [k] memcpy + 5.57% ovs-vswitchd [k] memcpy + 2.81% vhost-8471 [k] csum_partial_copy_generic to: + 5.72% ovs-vswitchd [k] memcpy + 3.32% vhost-5153 [k] memcpy + 0.68% vhost-5153 [k] skb_zerocopy (megaflows disabled) Signed-off-by: Thomas Graf Reviewed-by: Daniel Borkmann --- net/openvswitch/datapath.c | 54 +++++++++++++++++++++++++++++++--------------- 1 file changed, 37 insertions(+), 17 deletions(-) diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 72cdffb..237f7d7 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -108,10 +108,10 @@ int lockdep_ovsl_is_held(void) #endif static struct vport *new_vport(const struct vport_parms *); -static int queue_gso_packets(struct net *, int dp_ifindex, struct sk_buff *, - const struct dp_upcall_info *); -static int queue_userspace_packet(struct net *, int dp_ifindex, - struct sk_buff *, +static int queue_gso_packets(struct datapath *, struct net *, int dp_ifindex, + struct sk_buff *, const struct dp_upcall_info *); +static int queue_userspace_packet(struct datapath *, struct net *, + int dp_ifindex, struct sk_buff *, const struct dp_upcall_info *); /* Must be called with rcu_read_lock or ovs_mutex. */ @@ -292,9 +292,9 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb, } if (!skb_is_gso(skb)) - err = queue_userspace_packet(ovs_dp_get_net(dp), dp_ifindex, skb, upcall_info); + err = queue_userspace_packet(dp, ovs_dp_get_net(dp), dp_ifindex, skb, upcall_info); else - err = queue_gso_packets(ovs_dp_get_net(dp), dp_ifindex, skb, upcall_info); + err = queue_gso_packets(dp, ovs_dp_get_net(dp), dp_ifindex, skb, upcall_info); if (err) goto err; @@ -310,7 +310,7 @@ err: return err; } -static int queue_gso_packets(struct net *net, int dp_ifindex, +static int queue_gso_packets(struct datapath *dp, struct net *net, int dp_ifindex, struct sk_buff *skb, const struct dp_upcall_info *upcall_info) { @@ -327,7 +327,7 @@ static int queue_gso_packets(struct net *net, int dp_ifindex, /* Queue all of the segments. */ skb = segs; do { - err = queue_userspace_packet(net, dp_ifindex, skb, upcall_info); + err = queue_userspace_packet(dp, net, dp_ifindex, skb, upcall_info); if (err) break; @@ -381,10 +381,11 @@ static size_t key_attr_size(void) } static size_t upcall_msg_size(const struct sk_buff *skb, - const struct nlattr *userdata) + const struct nlattr *userdata, + unsigned int hdrlen) { size_t size = NLMSG_ALIGN(sizeof(struct ovs_header)) - + nla_total_size(skb->len) /* OVS_PACKET_ATTR_PACKET */ + + nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */ + nla_total_size(key_attr_size()); /* OVS_PACKET_ATTR_KEY */ /* OVS_PACKET_ATTR_USERDATA */ @@ -394,8 +395,8 @@ static size_t upcall_msg_size(const struct sk_buff *skb, return size; } -static int queue_userspace_packet(struct net *net, int dp_ifindex, - struct sk_buff *skb, +static int queue_userspace_packet(struct datapath *dp, struct net *net, + int dp_ifindex, struct sk_buff *skb, const struct dp_upcall_info *upcall_info) { struct ovs_header *upcall; @@ -407,6 +408,7 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, .snd_portid = upcall_info->portid, }; size_t len; + unsigned int hlen; int err; if (vlan_tx_tag_present(skb)) { @@ -427,7 +429,21 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, goto out; } - len = upcall_msg_size(skb, upcall_info->userdata); + /* Complete checksum if needed */ + if (skb->ip_summed == CHECKSUM_PARTIAL && + (err = skb_checksum_help(skb))) + goto out; + + /* Older versions of OVS user space enforce alignment of the last + * Netlink attribute to NLA_ALIGNTO which would require extensive + * padding logic. Only perform zerocopy if padding is not required. + */ + if (dp->user_features & OVS_DP_F_UNALIGNED) + hlen = skb_zerocopy_headlen(skb); + else + hlen = skb->len; + + len = upcall_msg_size(skb, upcall_info->userdata, hlen); user_skb = genlmsg_new_unicast(len, &info, GFP_ATOMIC); if (!user_skb) { err = -ENOMEM; @@ -447,13 +463,17 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex, nla_len(upcall_info->userdata), nla_data(upcall_info->userdata)); - nla = __nla_reserve(user_skb, OVS_PACKET_ATTR_PACKET, skb->len); + /* Only reserve room for attribute header, packet data is added + * in skb_zerocopy() */ + if (!(nla = nla_reserve(user_skb, OVS_PACKET_ATTR_PACKET, 0))) + goto out; + nla->nla_len = nla_attr_size(skb->len); + + skb_zerocopy(user_skb, skb, skb->len, hlen); - skb_copy_and_csum_dev(skb, nla_data(nla)); + ((struct nlmsghdr *) user_skb->data)->nlmsg_len = user_skb->len; - genlmsg_end(user_skb, upcall); err = genlmsg_unicast(net, user_skb, upcall_info->portid); - out: kfree_skb(nskb); return err;