From patchwork Wed Jun 19 22:31:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Wang X-Patchwork-Id: 1119050 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="LIE4Dg9w"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45TfpG6ZWbz9s5c for ; Thu, 20 Jun 2019 08:32:22 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730587AbfFSWcW (ORCPT ); Wed, 19 Jun 2019 18:32:22 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:43833 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730182AbfFSWcS (ORCPT ); Wed, 19 Jun 2019 18:32:18 -0400 Received: by mail-pg1-f195.google.com with SMTP id f25so426688pgv.10 for ; Wed, 19 Jun 2019 15:32:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=UfXiWrDNVd1YNRVEVnBNuKA+zj+k+vrtb3sOAGihE6M=; b=LIE4Dg9wIC2wrdqfWS6+XJhikgClvIFQtkqHr7SLOVGp/Z/UDxW/EY1gGz7fv7GpNJ PQx5Y+n4N1L46wXTnmBpWQpsBTk0SqKkbIXAaVvmNLEfRQCYAZJSHcpbnd05hwtPCKKf sUpxf/4IP6Gc0VpU6joyLyhLyvb2CsyUHR9Jgqrq10F4iJJdl59R4VSRq2scQ1KseR2c 9fkVgbkvHc/XtbOZJpEJwv8w/PSfPRR174Huh0iKuhZeVdu0p762HxYYYiUmMX2AU0Py t/3zXu4gywpjQLvcvuArTmH4VUkYQxE/azb7amOZLDZTi6As005m9rTWpJTHe42dWVN7 INFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=UfXiWrDNVd1YNRVEVnBNuKA+zj+k+vrtb3sOAGihE6M=; b=G718F0TY3kfiuUiHTQVdnznS1Ggbz4qKdtCUiq/h4d7DXGWzTUId9g67IM3G6GNLAu gmSNPJqkAGINVJW9kzYs0lMNUkmojSSkASgtiIk2gAqxFNXtdqcOhgOOUZ9shktL9+i2 04L17Yd1v8JW6l5X3Dx5nZcxW0rqkck8DI8FCTKKDp9E8BHAMpFRFi3qmtqh44CSa93N wkiRJ4DE0HZxzsrU/vNKnGqtR9P4RWEvxfwpKnJQQVevlIE3TQLCTjKosUBbzEp7rLIF F1Bku/Sm18aLu/cVG8/ylM2WXlk4iBOamUdRRkV1Ue6mZ7GcJ5UAqsE/QLXB+82GqCks KB6A== X-Gm-Message-State: APjAAAVG/HNan6uZgBFpmOd/lFgiZiSg8kamJUp51F/+8WJo+W0ZNPJ0 OO1gGa04mNQ1n5gXfzFbg+4= X-Google-Smtp-Source: APXvYqzngSsrBQQBOa8Qw2e3D8L+EfLEmwpOQH+fc2fEbuNLGab/lKnjgXQs6eD4NNl+jIGYQ067RA== X-Received: by 2002:a17:90a:a601:: with SMTP id c1mr13074061pjq.24.1560983537075; Wed, 19 Jun 2019 15:32:17 -0700 (PDT) Received: from weiwan0.svl.corp.google.com ([2620:15c:2c4:201:9310:64cb:677b:dcba]) by smtp.gmail.com with ESMTPSA id g8sm20037687pgd.29.2019.06.19.15.32.15 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 19 Jun 2019 15:32:16 -0700 (PDT) From: Wei Wang To: David Miller , netdev@vger.kernel.org Cc: Eric Dumazet , Mahesh Bandewar , Martin KaFai Lau , David Ahern , Wei Wang Subject: [PATCH v2 net-next 5/5] ipv6: convert major tx path to use RT6_LOOKUP_F_DST_NOREF Date: Wed, 19 Jun 2019 15:31:58 -0700 Message-Id: <20190619223158.35829-6-tracywwnj@gmail.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog In-Reply-To: <20190619223158.35829-1-tracywwnj@gmail.com> References: <20190619223158.35829-1-tracywwnj@gmail.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Wei Wang For tx path, in most cases, we still have to take refcnt on the dst cause the caller is caching the dst somewhere. But it still is beneficial to make use of RT6_LOOKUP_F_DST_NOREF flag while doing the route lookup. It is cause this flag prevents manipulating refcnt on net->ipv6.ip6_null_entry when doing fib6_rule_lookup() to traverse each routing table. The null_entry is a shared object and constant updates on it cause false sharing. We converted the current major lookup function ip6_route_output_flags() to make use of RT6_LOOKUP_F_DST_NOREF. Together with the change in the rx path, we see noticable performance boost: I ran synflood tests between 2 hosts under the same switch. Both hosts have 20G mlx NIC, and 8 tx/rx queues. Sender sends pure SYN flood with random src IPs and ports using trafgen. Receiver has a simple TCP listener on the target port. Both hosts have multiple custom rules: - For incoming packets, only local table is traversed. - For outgoing packets, 3 tables are traversed to find the route. The packet processing rate on the receiver is as follows: - Before the fix: 3.78Mpps - After the fix: 5.50Mpps Signed-off-by: Wei Wang Acked-by: Eric Dumazet Acked-by: Mahesh Bandewar --- drivers/net/vrf.c | 11 ++++++----- include/net/ip6_route.h | 25 +++++++++++++++++++++++-- include/net/l3mdev.h | 11 +++++++---- net/ipv6/route.c | 10 ++++++---- net/l3mdev/l3mdev.c | 22 +++++++++++----------- 5 files changed, 53 insertions(+), 26 deletions(-) diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 11b9525dff27..1d1ac78b167e 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -1072,12 +1072,14 @@ static struct sk_buff *vrf_l3_rcv(struct net_device *vrf_dev, #if IS_ENABLED(CONFIG_IPV6) /* send to link-local or multicast address via interface enslaved to * VRF device. Force lookup to VRF table without changing flow struct + * No refcnt is taken on the dst. */ -static struct dst_entry *vrf_link_scope_lookup(const struct net_device *dev, - struct flowi6 *fl6) +static struct dst_entry *vrf_link_scope_lookup_noref( + const struct net_device *dev, + struct flowi6 *fl6) { struct net *net = dev_net(dev); - int flags = RT6_LOOKUP_F_IFACE; + int flags = RT6_LOOKUP_F_IFACE | RT6_LOOKUP_F_DST_NOREF; struct dst_entry *dst = NULL; struct rt6_info *rt; @@ -1087,7 +1089,6 @@ static struct dst_entry *vrf_link_scope_lookup(const struct net_device *dev, */ if (fl6->flowi6_oif == dev->ifindex) { dst = &net->ipv6.ip6_null_entry->dst; - dst_hold(dst); return dst; } @@ -1107,7 +1108,7 @@ static const struct l3mdev_ops vrf_l3mdev_ops = { .l3mdev_l3_rcv = vrf_l3_rcv, .l3mdev_l3_out = vrf_l3_out, #if IS_ENABLED(CONFIG_IPV6) - .l3mdev_link_scope_lookup = vrf_link_scope_lookup, + .l3mdev_link_scope_lookup_noref = vrf_link_scope_lookup_noref, #endif }; diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 0709835c01ad..66802ecd81e5 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -84,8 +84,29 @@ struct dst_entry *ip6_route_input_lookup(struct net *net, struct flowi6 *fl6, const struct sk_buff *skb, int flags); -struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk, - struct flowi6 *fl6, int flags); +struct dst_entry *ip6_route_output_flags_noref(struct net *net, + const struct sock *sk, + struct flowi6 *fl6, int flags); + +static inline struct dst_entry *ip6_route_output_flags(struct net *net, + const struct sock *sk, + struct flowi6 *fl6, + int flags) { + struct dst_entry *dst; + struct rt6_info *rt6; + + rcu_read_lock(); + dst = ip6_route_output_flags_noref(net, sk, fl6, flags); + rt6 = (struct rt6_info *)dst; + /* For dst cached in uncached_list, refcnt is already taken. */ + if (list_empty(&rt6->rt6i_uncached) && !dst_hold_safe(dst)) { + dst = &net->ipv6.ip6_null_entry->dst; + dst_hold(dst); + } + rcu_read_unlock(); + + return dst; +} static inline struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk, diff --git a/include/net/l3mdev.h b/include/net/l3mdev.h index e942372b077b..d8c37317bb86 100644 --- a/include/net/l3mdev.h +++ b/include/net/l3mdev.h @@ -31,8 +31,9 @@ struct l3mdev_ops { u16 proto); /* IPv6 ops */ - struct dst_entry * (*l3mdev_link_scope_lookup)(const struct net_device *dev, - struct flowi6 *fl6); + struct dst_entry * (*l3mdev_link_scope_lookup_noref)( + const struct net_device *dev, + struct flowi6 *fl6); }; #ifdef CONFIG_NET_L3_MASTER_DEV @@ -140,7 +141,8 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex) return rc; } -struct dst_entry *l3mdev_link_scope_lookup(struct net *net, struct flowi6 *fl6); +struct dst_entry *l3mdev_link_scope_lookup_noref(struct net *net, + struct flowi6 *fl6); static inline struct sk_buff *l3mdev_l3_rcv(struct sk_buff *skb, u16 proto) @@ -251,7 +253,8 @@ static inline bool netif_index_is_l3_master(struct net *net, int ifindex) } static inline -struct dst_entry *l3mdev_link_scope_lookup(struct net *net, struct flowi6 *fl6) +struct dst_entry *l3mdev_link_scope_lookup_noref(struct net *net, + struct flowi6 *fl6) { return NULL; } diff --git a/net/ipv6/route.c b/net/ipv6/route.c index d2b287635aab..602d00794b30 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2415,8 +2415,9 @@ static struct rt6_info *ip6_pol_route_output(struct net *net, return ip6_pol_route(net, table, fl6->flowi6_oif, fl6, skb, flags); } -struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk, - struct flowi6 *fl6, int flags) +struct dst_entry *ip6_route_output_flags_noref(struct net *net, + const struct sock *sk, + struct flowi6 *fl6, int flags) { bool any_src; @@ -2424,13 +2425,14 @@ struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk, (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL)) { struct dst_entry *dst; - dst = l3mdev_link_scope_lookup(net, fl6); + dst = l3mdev_link_scope_lookup_noref(net, fl6); if (dst) return dst; } fl6->flowi6_iif = LOOPBACK_IFINDEX; + flags |= RT6_LOOKUP_F_DST_NOREF; any_src = ipv6_addr_any(&fl6->saddr); if ((sk && sk->sk_bound_dev_if) || rt6_need_strict(&fl6->daddr) || (fl6->flowi6_oif && any_src)) @@ -2443,7 +2445,7 @@ struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk, return fib6_rule_lookup(net, fl6, NULL, flags, ip6_pol_route_output); } -EXPORT_SYMBOL_GPL(ip6_route_output_flags); +EXPORT_SYMBOL_GPL(ip6_route_output_flags_noref); struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_orig) { diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c index cfc9fcb97465..06133426549b 100644 --- a/net/l3mdev/l3mdev.c +++ b/net/l3mdev/l3mdev.c @@ -114,35 +114,35 @@ u32 l3mdev_fib_table_by_index(struct net *net, int ifindex) EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index); /** - * l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link - * local and multicast addresses + * l3mdev_link_scope_lookup_noref - IPv6 route lookup based on flow + * for link local and multicast addresses * @net: network namespace for device index lookup * @fl6: IPv6 flow struct for lookup + * This function does not hold refcnt on the returned dst. + * Caller must hold rcu_read_lock(). */ -struct dst_entry *l3mdev_link_scope_lookup(struct net *net, - struct flowi6 *fl6) +struct dst_entry *l3mdev_link_scope_lookup_noref(struct net *net, + struct flowi6 *fl6) { struct dst_entry *dst = NULL; struct net_device *dev; + WARN_ON_ONCE(!rcu_read_lock_held()); if (fl6->flowi6_oif) { - rcu_read_lock(); - dev = dev_get_by_index_rcu(net, fl6->flowi6_oif); if (dev && netif_is_l3_slave(dev)) dev = netdev_master_upper_dev_get_rcu(dev); if (dev && netif_is_l3_master(dev) && - dev->l3mdev_ops->l3mdev_link_scope_lookup) - dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6); - - rcu_read_unlock(); + dev->l3mdev_ops->l3mdev_link_scope_lookup_noref) + dst = dev->l3mdev_ops-> + l3mdev_link_scope_lookup_noref(dev, fl6); } return dst; } -EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup); +EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup_noref); /** * l3mdev_fib_rule_match - Determine if flowi references an