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[2620:137:e000::1:20]) by mx.google.com with ESMTP id p23-20020a056402045700b004a21a662064si3474767edw.352.2023.02.22.07.28.05; Wed, 22 Feb 2023 07:28:29 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b="JfWmM/US"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232321AbjBVPNN (ORCPT + 99 others); Wed, 22 Feb 2023 10:13:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231935AbjBVPNE (ORCPT ); Wed, 22 Feb 2023 10:13:04 -0500 Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E31AE34F47; Wed, 22 Feb 2023 07:13:02 -0800 (PST) Received: by mail-wr1-x42a.google.com with SMTP id j2so7907140wrh.9; Wed, 22 Feb 2023 07:13:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:to:from:date:from:to:cc:subject:date:message-id :reply-to; bh=fGph5Raoba9CAF6fBIYY6MSZIRHm6UMtwUQalrVn88o=; b=JfWmM/US7NI+suWhR4epn0jG9yVCtlPNZgvEnPqmXU4moemzaZcBPE7RzEncTk1V3k NDkmGVVtu1osrGDVlGtDUuIC1cOchjH92yWOOSlCz9QIs7Lzk4Q59U3QEOfNHwsYb93m IlZD0vkuPEzgUB89olYmx9VVzfakET83oSkf0CAYyGx0cHqVxQO8ftauGzj7GKNWMTxj d/FjpglhyCpwGDSK8Fk4Ox50XWAEaW3Jqx08IpG2G4wtWqkI65RxC2az7yw9kTfFFAin JNdu57PgAC8XIJhnlz1TfWuPLUq3vr4yWMoVhGew4EJFZ1HlX7cNJ7990OH8s63wWlFL 6kGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=fGph5Raoba9CAF6fBIYY6MSZIRHm6UMtwUQalrVn88o=; b=dSs5JMDDYYusSxjYu4z6YbUnDnhHRV/MzbKhtA1ZzBNWtmBaoUt+w4KN66m1pUWIOr lXHzJKSJQA7xZfzFilPYplQ9Xnwy3ZP6sl8x3xgXnyhZXzpSTyTzYLJblRuZtgMoBQvr qrHy5J97J4BgU2Loy+/WawNehjzgPkxxRtniwH96DdkU5zxnRmxGm4kf1qdCdQ7znb5f Ur8CpkoTxFxFqZR+8SNkLCr+FAzcwss++zD3KBPbAAI4xyn8Brp9sn8eJ7mIhdU45nrr 3ub9Nk7LEWIrN3uWIOgqmnOXqUdXCqAOP3fktFI2+sJaWPlRPT24dj9MyRQBCPed61a/ QxnA== X-Gm-Message-State: AO0yUKWYtztsu0j34F3nS8bUoL4424GytVkZ+pGgrPphBjVi326U80P8 NsfMKzbklHsDyDC7prr50+g= X-Received: by 2002:a5d:4e8d:0:b0:2c7:daa:1c56 with SMTP id e13-20020a5d4e8d000000b002c70daa1c56mr928571wru.4.1677078781393; Wed, 22 Feb 2023 07:13:01 -0800 (PST) Received: from debian ([89.238.191.199]) by smtp.gmail.com with ESMTPSA id o1-20020a5d58c1000000b002c53f5b13f9sm8536228wrf.0.2023.02.22.07.12.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Feb 2023 07:13:01 -0800 (PST) Date: Wed, 22 Feb 2023 16:12:38 +0100 From: Richard Gobert To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, alexanderduyck@fb.com, lixiaoyan@google.com, steffen.klassert@secunet.com, lucien.xin@gmail.com, ye.xingchen@zte.com.cn, iwienand@redhat.com, leon@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] gro: optimise redundant parsing of packets Message-ID: <20230222151236.GB12658@debian> References: <20230222145917.GA12590@debian> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230222145917.GA12590@debian> User-Agent: Mutt/1.10.1 (2018-07-13) X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1756453214308186278?= X-GMAIL-MSGID: =?utf-8?q?1758545533619744640?= Currently the IPv6 extension headers are parsed twice: first in ipv6_gro_receive, and then again in ipv6_gro_complete. By using the new ->transport_proto field, and also storing the size of the network header, we can avoid parsing extension headers a second time in ipv6_gro_complete (which saves multiple memory dereferences and conditional checks inside ipv6_exthdrs_len for a varying amount of extension headers in IPv6 packets). The implementation had to handle both inner and outer layers in case of encapsulation (as they can't use the same field). Performance tests for TCP stream over IPv6 with a varying amount of extension headers demonstrate throughput improvement of ~0.7%. In addition, I fixed a potential existing problem: - The call to skb_set_inner_network_header at the beginning of ipv6_gro_complete calculates inner_network_header based on skb->data by calling skb_set_inner_network_header, and setting it to point to the beginning of the ip header. - If a packet is going to be handled by BIG TCP, the following code block is going to shift the packet header, and skb->data is going to be changed as well. When the two flows are combined, inner_network_header will point to the wrong place. The fix is to place the whole encapsulation branch after the BIG TCP code block. This way, inner_network_header is calculated with a correct value of skb->data. Also, by arranging the code that way, the optimisation does not add an additional branch. Signed-off-by: Richard Gobert --- include/net/gro.h | 9 +++++++++ net/ethernet/eth.c | 14 +++++++++++--- net/ipv6/ip6_offload.c | 20 +++++++++++++++----- 3 files changed, 35 insertions(+), 8 deletions(-) diff --git a/include/net/gro.h b/include/net/gro.h index 7b47dd6ce94f..35f60ea99f6c 100644 --- a/include/net/gro.h +++ b/include/net/gro.h @@ -86,6 +86,15 @@ struct napi_gro_cb { /* used to support CHECKSUM_COMPLETE for tunneling protocols */ __wsum csum; + + /* Used in ipv6_gro_receive() */ + u16 network_len; + + /* Used in eth_gro_receive() */ + __be16 network_proto; + + /* Used in ipv6_gro_receive() */ + u8 transport_proto; }; #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb) diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index 2edc8b796a4e..c2b77d9401e4 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -439,6 +439,9 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb) goto out; } + if (!NAPI_GRO_CB(skb)->encap_mark) + NAPI_GRO_CB(skb)->network_proto = type; + skb_gro_pull(skb, sizeof(*eh)); skb_gro_postpull_rcsum(skb, eh, sizeof(*eh)); @@ -455,13 +458,18 @@ EXPORT_SYMBOL(eth_gro_receive); int eth_gro_complete(struct sk_buff *skb, int nhoff) { - struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff); - __be16 type = eh->h_proto; struct packet_offload *ptype; + struct ethhdr *eh; int err = -ENOSYS; + __be16 type; - if (skb->encapsulation) + if (skb->encapsulation) { + eh = (struct ethhdr *)(skb->data + nhoff); skb_set_inner_mac_header(skb, nhoff); + type = eh->h_proto; + } else { + type = NAPI_GRO_CB(skb)->network_proto; + } ptype = gro_find_complete_by_type(type); if (ptype != NULL) diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 00dc2e3b0184..6e3a923ad573 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -232,6 +232,11 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, flush--; nlen = skb_network_header_len(skb); + if (!NAPI_GRO_CB(skb)->encap_mark) { + NAPI_GRO_CB(skb)->transport_proto = proto; + NAPI_GRO_CB(skb)->network_len = nlen; + } + list_for_each_entry(p, head, list) { const struct ipv6hdr *iph2; __be32 first_word; /* */ @@ -324,10 +329,6 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) int err = -ENOSYS; u32 payload_len; - if (skb->encapsulation) { - skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); - skb_set_inner_network_header(skb, nhoff); - } payload_len = skb->len - nhoff - sizeof(*iph); if (unlikely(payload_len > IPV6_MAXPLEN)) { @@ -341,6 +342,7 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) skb->len += hoplen; skb->mac_header -= hoplen; skb->network_header -= hoplen; + NAPI_GRO_CB(skb)->network_len += hoplen; iph = (struct ipv6hdr *)(skb->data + nhoff); hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1); @@ -358,7 +360,15 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) iph->payload_len = htons(payload_len); } - nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); + if (skb->encapsulation) { + skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); + skb_set_inner_network_header(skb, nhoff); + nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); + } else { + ops = rcu_dereference(inet6_offloads[NAPI_GRO_CB(skb)->transport_proto]); + nhoff += NAPI_GRO_CB(skb)->network_len; + } + if (WARN_ON(!ops || !ops->callbacks.gro_complete)) goto out;