From nobody Mon Nov 25 20:46:31 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 DC9DB1DFF5; Fri, 25 Oct 2024 13:46:24 +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=1729863988; cv=none; b=CPU9Y9rfcZFgMQf9IwLqX4r4FKG48SnqpEIC/hAsoEQvhlMjemZrydCeXsCVTQhmsm0MNwgcOjm8+F1W3IfQZ5BzdTBA+S3HGRMDJaBtezmivuTwg+64+nLVMb5DQ1vZfSZV34YDf0DbAsCFzNgvi4yuCCns6HqDAzA32c4dxys= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729863988; c=relaxed/simple; bh=Xn/iAWW87UHsfh2vqmaJ638Sc5zPdn891175iWHYZQg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=G37O6ZjENxl2Jpx2ObQpjYv2UjT6HSBp0pYjHiSAUwP6PXJhHtn87/LsTLjismryHKD9N1iNpj1UqLquGM4HYlOfGaROs+Cs3LSrhw7cVG3M1rd9hoFH+tBV4W3DhQSBtAtiY4TD+IOwMqF/ssDsldBHYQfAH0U/IqUOrKFKC4U= 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=R9VWmsMk; 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="R9VWmsMk" Received: from localhost.localdomain (220.24-245-81.adsl-dyn.isp.belgacom.be [81.245.24.220]) (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 1FA39200EECA; Fri, 25 Oct 2024 15:37:50 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 serv108.segi.ulg.ac.be 1FA39200EECA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uliege.be; s=ulg20190529; t=1729863470; bh=M2cIWafnBBKhhrEbmEIY+ACXf3R2haiNwub60/8/wiU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R9VWmsMkgk4eo20BmI3r6eqsulFVIry7dOitICEQl9ktxHjEhN3iHURcsi39tHfDG sF1nqSwkiuedl05UlCecS5FbQabXFLawDARpTXgercAtx8CN/zHXYs0bI/yi0zsIli JK1U2J753RuyMRBZVrRi53C8iArlvZ48fJOCjNxnZ9KE+NC5VdK4ZE1nU9OkT5oO9O M6lJKkAWvxRhGyTzQImEZN12n5Hv7RwC7izFP7QAmgzPTUwYLcuZfxrDfbj52FqZDg KWFKX72O+URj+vc1nw7zRatpxRpWUG3bOnYqTGBoEYeZA3lJeeYnYVCWkFmHR9n9tC GHSaHrQuYfaLQ== 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 Subject: [PATCH net-next 3/3] net: ipv6: rpl_iptunnel: mitigate 2-realloc issue Date: Fri, 25 Oct 2024 15:37:27 +0200 Message-Id: <20241025133727.27742-4-justin.iurman@uliege.be> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241025133727.27742-1-justin.iurman@uliege.be> References: <20241025133727.27742-1-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 rpl_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 there is no impact (it even shows improvement): - before: https://ibb.co/nQJhqwc - after: https://ibb.co/4ZvW6wV Signed-off-by: Justin Iurman --- net/ipv6/rpl_iptunnel.c | 60 +++++++++++++++++++++-------------------- 1 file changed, 31 insertions(+), 29 deletions(-) diff --git a/net/ipv6/rpl_iptunnel.c b/net/ipv6/rpl_iptunnel.c index db3c19a42e1c..ce722d9ec711 100644 --- a/net/ipv6/rpl_iptunnel.c +++ b/net/ipv6/rpl_iptunnel.c @@ -125,7 +125,8 @@ static void rpl_destroy_state(struct lwtunnel_state *lw= t) } =20 static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rl= wt, - const struct ipv6_rpl_sr_hdr *srh) + const struct ipv6_rpl_sr_hdr *srh, + struct dst_entry *dst) { struct ipv6_rpl_sr_hdr *isrh, *csrh; const struct ipv6hdr *oldhdr; @@ -153,7 +154,8 @@ static int rpl_do_srh_inline(struct sk_buff *skb, const= struct rpl_lwt *rlwt, =20 hdrlen =3D ((csrh->hdrlen + 1) << 3); =20 - err =3D skb_cow_head(skb, hdrlen + skb->mac_len); + err =3D skb_cow_head(skb, hdrlen + (!dst ? skb->mac_len + : LL_RESERVED_SPACE(dst->dev))); if (unlikely(err)) { kfree(buf); return err; @@ -186,36 +188,35 @@ static int rpl_do_srh_inline(struct sk_buff *skb, con= st struct rpl_lwt *rlwt, return 0; } =20 -static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt) +static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt, + struct dst_entry *dst) { - struct dst_entry *dst =3D skb_dst(skb); struct rpl_iptunnel_encap *tinfo; =20 if (skb->protocol !=3D htons(ETH_P_IPV6)) return -EINVAL; =20 - tinfo =3D rpl_encap_lwtunnel(dst->lwtstate); + tinfo =3D rpl_encap_lwtunnel(skb_dst(skb)->lwtstate); =20 - return rpl_do_srh_inline(skb, rlwt, tinfo->srh); + return rpl_do_srh_inline(skb, rlwt, tinfo->srh, dst); } =20 static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *sk= b) { - struct dst_entry *orig_dst =3D skb_dst(skb); - struct dst_entry *dst =3D NULL; + struct dst_entry *dst; struct rpl_lwt *rlwt; int err; =20 - rlwt =3D rpl_lwt_lwtunnel(orig_dst->lwtstate); - - err =3D rpl_do_srh(skb, rlwt); - if (unlikely(err)) - goto drop; + rlwt =3D rpl_lwt_lwtunnel(skb_dst(skb)->lwtstate); =20 local_bh_disable(); dst =3D dst_cache_get(&rlwt->cache); local_bh_enable(); =20 + err =3D rpl_do_srh(skb, rlwt, dst); + if (unlikely(err)) + goto drop; + if (unlikely(!dst)) { struct ipv6hdr *hdr =3D ipv6_hdr(skb); struct flowi6 fl6; @@ -237,15 +238,15 @@ static int rpl_output(struct net *net, struct sock *s= k, struct sk_buff *skb) local_bh_disable(); dst_cache_set_ip6(&rlwt->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; - return dst_output(net, sk, skb); =20 drop: @@ -255,36 +256,37 @@ static int rpl_output(struct net *net, struct sock *s= k, struct sk_buff *skb) =20 static int rpl_input(struct sk_buff *skb) { - struct dst_entry *orig_dst =3D skb_dst(skb); - struct dst_entry *dst =3D NULL; + struct dst_entry *dst; struct rpl_lwt *rlwt; int err; =20 - rlwt =3D rpl_lwt_lwtunnel(orig_dst->lwtstate); - - err =3D rpl_do_srh(skb, rlwt); - if (unlikely(err)) - goto drop; + rlwt =3D rpl_lwt_lwtunnel(skb_dst(skb)->lwtstate); =20 local_bh_disable(); dst =3D dst_cache_get(&rlwt->cache); + local_bh_enable(); + + err =3D rpl_do_srh(skb, rlwt, 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(&rlwt->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 return dst_input(skb); =20 --=20 2.34.1