From nobody Mon Nov 25 09:20:40 2024 Received: from serv108.segi.ulg.ac.be (serv108.segi.ulg.ac.be [139.165.32.111]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0CE21FB3C7; Mon, 28 Oct 2024 22:36:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=139.165.32.111 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730154990; cv=none; b=BfdGIkpjUpfXIYvcyZNwbOsHAcUTFkPqtxWBUrEBYrHM7vp4T+0asSuyDtQ/tl2q9CoyJ5YQLQnN9z+1cDDtlhSE4zwzB33O97NHBkoC7ykYAOMoKJJg3gwq7gaRiepxVIhLta3BX2A4/5ZzevQCTyYUbjENflnr5Ei1uozoXfo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730154990; c=relaxed/simple; bh=F+Kch8QcQm0e2n51XjRxKVnnp6x1IQqXuvWnVDWBKtA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FBlzogoGjZCX4XVRk6UU8KBCs4x0Qn1KX/aXbObhpLEQLw0qTrEaI/rK8eP43aTSUiIUroTZipCABkB9QAVA3BwLYvxdh25P+Kp+JQGgxhMqvnZdrFhiYCemJBSQwJDF99OLhTDqgrX4uTWNkZsnRqvb3c9feneYZP28Ft4jBMY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uliege.be; spf=pass smtp.mailfrom=uliege.be; dkim=pass (2048-bit key) header.d=uliege.be header.i=@uliege.be header.b=B0AwhY5A; arc=none smtp.client-ip=139.165.32.111 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=uliege.be Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=uliege.be Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=uliege.be header.i=@uliege.be header.b="B0AwhY5A" Received: from localhost.localdomain (unknown [10.29.254.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by serv108.segi.ulg.ac.be (Postfix) with ESMTPSA id 9A61B200DF86; Mon, 28 Oct 2024 23:36:24 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 serv108.segi.ulg.ac.be 9A61B200DF86 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uliege.be; s=ulg20190529; t=1730154986; bh=UaQciTD4ZGTg4f/BHtguYrwhrAoAfYm+2RDAq6IW+H4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B0AwhY5AjyMbAegCzDELt40BZu/TtInysZsF+gZMPJ1WtchmVtZqS94oIfuDhLD4L /j8NjuewR7y0Qmd7dsgKhFWC5slW6ZkkB/0LX8qu7QqpEXD90jvGAeZX7XuK4yheve y/L3PUHlXWgX6d8sU/pY4VA5iqXZ40lu+1rRtrHTnY/iRqrlBZIivKUexzmTYtIbux 9uFEs3apk5wIgxrhWHIsS7w0JiiJ95FmbgU/y6ogOiZ9HUhC4cyzY9zHL44hKPb8A0 8yTerPaRNQLwq85L2ebhL2nztmsRxQw8b0kXZ8uxEVPHis6n6omH54aJWvvnhmL1rL sIKrNt7Si19ew== From: Justin Iurman To: netdev@vger.kernel.org Cc: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-kernel@vger.kernel.org, justin.iurman@uliege.be, David Lebrun Subject: [PATCH net-next v3 2/3] net: ipv6: seg6_iptunnel: mitigate 2-realloc issue Date: Mon, 28 Oct 2024 23:36:10 +0100 Message-Id: <20241028223611.26599-3-justin.iurman@uliege.be> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241028223611.26599-1-justin.iurman@uliege.be> References: <20241028223611.26599-1-justin.iurman@uliege.be> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch mitigates the two-reallocations issue with seg6_iptunnel by providing the dst_entry (in the cache) to the first call to skb_cow_head(). As a result, the very first iteration would still trigger two reallocations (i.e., empty cache), while next iterations would only trigger a single reallocation. Performance tests before/after applying this patch, which clearly shows the improvement: - before: https://ibb.co/3Cg4sNH - after: https://ibb.co/8rQ350r Signed-off-by: Justin Iurman Cc: David Lebrun --- net/ipv6/seg6_iptunnel.c | 114 ++++++++++++++++++++++----------------- 1 file changed, 66 insertions(+), 48 deletions(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index 098632adc9b5..1897e1338bb8 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -124,11 +124,18 @@ static __be32 seg6_make_flowlabel(struct net *net, st= ruct sk_buff *skb, return flowlabel; } =20 -/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH= */ -int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int p= roto) +static inline int dev_overhead(struct dst_entry *dst, struct sk_buff *skb) +{ + if (likely(dst)) + return LL_RESERVED_SPACE(dst->dev); + + return skb->mac_len; +} + +static int __seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *os= rh, + int proto, struct dst_entry *dst) { - struct dst_entry *dst =3D skb_dst(skb); - struct net *net =3D dev_net(dst->dev); + struct net *net =3D dev_net(skb_dst(skb)->dev); struct ipv6hdr *hdr, *inner_hdr; struct ipv6_sr_hdr *isrh; int hdrlen, tot_len, err; @@ -137,7 +144,7 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_= sr_hdr *osrh, int proto) hdrlen =3D (osrh->hdrlen + 1) << 3; tot_len =3D hdrlen + sizeof(*hdr); =20 - err =3D skb_cow_head(skb, tot_len + skb->mac_len); + err =3D skb_cow_head(skb, tot_len + dev_overhead(dst, skb)); if (unlikely(err)) return err; =20 @@ -181,7 +188,7 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_= sr_hdr *osrh, int proto) isrh->nexthdr =3D proto; =20 hdr->daddr =3D isrh->segments[isrh->first_segment]; - set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr); + set_tun_src(net, skb_dst(skb)->dev, &hdr->daddr, &hdr->saddr); =20 #ifdef CONFIG_IPV6_SEG6_HMAC if (sr_has_hmac(isrh)) { @@ -197,15 +204,21 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv= 6_sr_hdr *osrh, int proto) =20 return 0; } + +/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH= */ +int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int p= roto) +{ + return __seg6_do_srh_encap(skb, osrh, proto, NULL); +} EXPORT_SYMBOL_GPL(seg6_do_srh_encap); =20 /* encapsulate an IPv6 packet within an outer IPv6 header with reduced SRH= */ static int seg6_do_srh_encap_red(struct sk_buff *skb, - struct ipv6_sr_hdr *osrh, int proto) + struct ipv6_sr_hdr *osrh, int proto, + struct dst_entry *dst) { __u8 first_seg =3D osrh->first_segment; - struct dst_entry *dst =3D skb_dst(skb); - struct net *net =3D dev_net(dst->dev); + struct net *net =3D dev_net(skb_dst(skb)->dev); struct ipv6hdr *hdr, *inner_hdr; int hdrlen =3D ipv6_optlen(osrh); int red_tlv_offset, tlv_offset; @@ -230,7 +243,7 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, =20 tot_len =3D red_hdrlen + sizeof(struct ipv6hdr); =20 - err =3D skb_cow_head(skb, tot_len + skb->mac_len); + err =3D skb_cow_head(skb, tot_len + dev_overhead(dst, skb)); if (unlikely(err)) return err; =20 @@ -263,7 +276,7 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, if (skip_srh) { hdr->nexthdr =3D proto; =20 - set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr); + set_tun_src(net, skb_dst(skb)->dev, &hdr->daddr, &hdr->saddr); goto out; } =20 @@ -299,7 +312,7 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, =20 srcaddr: isrh->nexthdr =3D proto; - set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr); + set_tun_src(net, skb_dst(skb)->dev, &hdr->daddr, &hdr->saddr); =20 #ifdef CONFIG_IPV6_SEG6_HMAC if (unlikely(!skip_srh && sr_has_hmac(isrh))) { @@ -317,8 +330,8 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb, return 0; } =20 -/* insert an SRH within an IPv6 packet, just after the IPv6 header */ -int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) +static int __seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *o= srh, + struct dst_entry *dst) { struct ipv6hdr *hdr, *oldhdr; struct ipv6_sr_hdr *isrh; @@ -326,7 +339,7 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6= _sr_hdr *osrh) =20 hdrlen =3D (osrh->hdrlen + 1) << 3; =20 - err =3D skb_cow_head(skb, hdrlen + skb->mac_len); + err =3D skb_cow_head(skb, hdrlen + dev_overhead(dst, skb)); if (unlikely(err)) return err; =20 @@ -369,22 +382,20 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ip= v6_sr_hdr *osrh) =20 return 0; } -EXPORT_SYMBOL_GPL(seg6_do_srh_inline); =20 -static int seg6_do_srh(struct sk_buff *skb) +static int seg6_do_srh(struct sk_buff *skb, struct dst_entry *dst) { - struct dst_entry *dst =3D skb_dst(skb); struct seg6_iptunnel_encap *tinfo; int proto, err =3D 0; =20 - tinfo =3D seg6_encap_lwtunnel(dst->lwtstate); + tinfo =3D seg6_encap_lwtunnel(skb_dst(skb)->lwtstate); =20 switch (tinfo->mode) { case SEG6_IPTUN_MODE_INLINE: if (skb->protocol !=3D htons(ETH_P_IPV6)) return -EINVAL; =20 - err =3D seg6_do_srh_inline(skb, tinfo->srh); + err =3D __seg6_do_srh_inline(skb, tinfo->srh, dst); if (err) return err; break; @@ -402,9 +413,9 @@ static int seg6_do_srh(struct sk_buff *skb) return -EINVAL; =20 if (tinfo->mode =3D=3D SEG6_IPTUN_MODE_ENCAP) - err =3D seg6_do_srh_encap(skb, tinfo->srh, proto); + err =3D __seg6_do_srh_encap(skb, tinfo->srh, proto, dst); else - err =3D seg6_do_srh_encap_red(skb, tinfo->srh, proto); + err =3D seg6_do_srh_encap_red(skb, tinfo->srh, proto, dst); =20 if (err) return err; @@ -425,11 +436,11 @@ static int seg6_do_srh(struct sk_buff *skb) skb_push(skb, skb->mac_len); =20 if (tinfo->mode =3D=3D SEG6_IPTUN_MODE_L2ENCAP) - err =3D seg6_do_srh_encap(skb, tinfo->srh, - IPPROTO_ETHERNET); + err =3D __seg6_do_srh_encap(skb, tinfo->srh, + IPPROTO_ETHERNET, dst); else err =3D seg6_do_srh_encap_red(skb, tinfo->srh, - IPPROTO_ETHERNET); + IPPROTO_ETHERNET, dst); =20 if (err) return err; @@ -444,6 +455,13 @@ static int seg6_do_srh(struct sk_buff *skb) return 0; } =20 +/* insert an SRH within an IPv6 packet, just after the IPv6 header */ +int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh) +{ + return __seg6_do_srh_inline(skb, osrh, NULL); +} +EXPORT_SYMBOL_GPL(seg6_do_srh_inline); + static int seg6_input_finish(struct net *net, struct sock *sk, struct sk_buff *skb) { @@ -453,36 +471,37 @@ static int seg6_input_finish(struct net *net, struct = sock *sk, static int seg6_input_core(struct net *net, struct sock *sk, struct sk_buff *skb) { - struct dst_entry *orig_dst =3D skb_dst(skb); - struct dst_entry *dst =3D NULL; + struct dst_entry *dst; struct seg6_lwt *slwt; int err; =20 - err =3D seg6_do_srh(skb); - if (unlikely(err)) - goto drop; - - slwt =3D seg6_lwt_lwtunnel(orig_dst->lwtstate); + slwt =3D seg6_lwt_lwtunnel(skb_dst(skb)->lwtstate); =20 local_bh_disable(); dst =3D dst_cache_get(&slwt->cache); + local_bh_enable(); + + err =3D seg6_do_srh(skb, dst); + if (unlikely(err)) + goto drop; =20 if (!dst) { ip6_route_input(skb); dst =3D skb_dst(skb); if (!dst->error) { + local_bh_disable(); dst_cache_set_ip6(&slwt->cache, dst, &ipv6_hdr(skb)->saddr); + local_bh_enable(); } + + err =3D skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + goto drop; } else { skb_dst_drop(skb); skb_dst_set(skb, dst); } - local_bh_enable(); - - err =3D skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); - if (unlikely(err)) - goto drop; =20 if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, @@ -523,21 +542,20 @@ static int seg6_input(struct sk_buff *skb) static int seg6_output_core(struct net *net, struct sock *sk, struct sk_buff *skb) { - struct dst_entry *orig_dst =3D skb_dst(skb); - struct dst_entry *dst =3D NULL; + struct dst_entry *dst; struct seg6_lwt *slwt; int err; =20 - err =3D seg6_do_srh(skb); - if (unlikely(err)) - goto drop; - - slwt =3D seg6_lwt_lwtunnel(orig_dst->lwtstate); + slwt =3D seg6_lwt_lwtunnel(skb_dst(skb)->lwtstate); =20 local_bh_disable(); dst =3D dst_cache_get(&slwt->cache); local_bh_enable(); =20 + err =3D seg6_do_srh(skb, dst); + if (unlikely(err)) + goto drop; + if (unlikely(!dst)) { struct ipv6hdr *hdr =3D ipv6_hdr(skb); struct flowi6 fl6; @@ -559,15 +577,15 @@ static int seg6_output_core(struct net *net, struct s= ock *sk, local_bh_disable(); dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr); local_bh_enable(); + + err =3D skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + goto drop; } =20 skb_dst_drop(skb); skb_dst_set(skb, dst); =20 - err =3D skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); - if (unlikely(err)) - goto drop; - if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled)) return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb, NULL, skb_dst(skb)->dev, dst_output); --=20 2.34.1