From patchwork Thu Mar 7 13:29:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Gobert X-Patchwork-Id: 778707 Received: from mail-wm1-f50.google.com (mail-wm1-f50.google.com [209.85.128.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AB821126F3E; Thu, 7 Mar 2024 13:30:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.50 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709818213; cv=none; b=dZ+n3SmWPapswrgf0+QrT6KGtg9R4hvy+GNg7K0iUWUJ197YBsfdcPQDl9ZW9Rjpb4TFxE32x6mL6AgfNFsGLlD61sgNbAzitvbi1u1DC1vT0POZh/xXXVuMgJSmMKrBswtLRrEfofZMMnryN69lT0VPzr6SziwRJF5ZRDgYtg0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709818213; c=relaxed/simple; bh=vkOMxHXD4nuVLrv6WmdabNYOCP9l1guIXj+KW4LR1do=; h=Message-ID:Date:MIME-Version:Subject:From:To:References: In-Reply-To:Content-Type; b=hpKZHh7eHozq+9SV8k4Jv5VAzK3nv8+PQJnQvHqMM11D04i6ekHAeGCqp47J/9AOl6c1AnuMQboFKwWP3F1HugyL76lrCLhexskTM3LECXYIG3rjcPTM5suM0S1zPyE/cncQGVK+aYt8lD2Nm1pq85jCN6G4QlO8ap+friGL2Ss= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=XraYcgVO; arc=none smtp.client-ip=209.85.128.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XraYcgVO" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-4130fefef75so4809155e9.2; Thu, 07 Mar 2024 05:30:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1709818210; x=1710423010; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:references:to:from:subject :mime-version:date:message-id:from:to:cc:subject:date:message-id :reply-to; bh=doHNYzpPaU/Jmbsj3ODm0NABIpGT3fJO+db8zfVfSF4=; b=XraYcgVOPnatI3ONhaT+eASEIROHPgRFlVjFLJb2G1UvczoDA2yCpkJOR8g5kol+Vy W9at145oa9raBPLIrqEpRwkgzlHdiwWIcx9v2+OcZlx7pYSwR2A1CT/bhIxEgAJ7368N HF8YJZ6SH0v2jZgbRl+MmxbS4mi7/m8OuDkFA0LJDzlhmSHQNxCJi/jFuApn3tD59VQn V/58wOV8a9STfo94b/OI5K781NTUQnYk6xAC6S2Kmpqz5kBjQHQ0WivoFt/3+miqsSfE RjoDdR5z2N1UGf6RmMC7d0SwktNLeDOrFbzhA4RKl+feaSg85yJw5bmnU7f0alKX79Pm sDaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709818210; x=1710423010; h=content-transfer-encoding:in-reply-to:references:to:from:subject :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=doHNYzpPaU/Jmbsj3ODm0NABIpGT3fJO+db8zfVfSF4=; b=eyRSHcA9ibHt6lXC7bT1j5C/UZHV3woLhe1r/65HWCNV/xiXsV9RBXgqEXs37HrRjP 28P2mYtqG7yWD87GYjt+ai3RXBGaKG4fBP1MsTGg8rpXp/i5/5G0qHmstLPfywH+NmHs RyFRdK8DbNNAYXZcb4+7KVKAljt0G1yIJHqpna4RFYYY9tniW2G3apL4VdjvcDlWst2M zAJIpRkJ9Wx4crunFEz3yuC6MCZ89r7bMk8s8PVKuSiHuoviF/EPf18p8W6/VDQkJePN kvEn8ZApXyzj19VRE+nxWqE/qIVNrsIfQMg0llJvMrHEEtxuY4S5ov1rXrOA4P0UB4b/ ox0A== X-Forwarded-Encrypted: i=1; AJvYcCVwVQ4jFeoX7sB5DvonbdVMcfHFpFXnrQCLjRD0wbqZ3+OAA5shCq0L2WzDJyeWW2gZJAId8Yl4A1qU10b9611Ho3zZJoQi7F+xMfM1wgJcSFP1ub4+KmzN6L9az8jH8BldNPj0W8BQXl/pRGiTwZCrPtfs0aLZdJNsg9vmznUWvlxqvthe X-Gm-Message-State: AOJu0YxuHrLpjxrKo1jqYi8w7Sa3tjA3GrIQgMTqcFSyOqS2Y/43H/pn HtGQAzkbZ9HWhMJbLqY26SGQyGjhNxfC9l2jaX94ATo92JgQljWk X-Google-Smtp-Source: AGHT+IGOXKOB/DpTDS46ZigfIY/sMM7eU8fn4aIS5/XqrPkFg4EAFhMM+QDivPnj6Mw6HerQOFA2fA== X-Received: by 2002:a05:600c:4fc3:b0:412:dc02:9824 with SMTP id o3-20020a05600c4fc300b00412dc029824mr10431099wmq.9.1709818209866; Thu, 07 Mar 2024 05:30:09 -0800 (PST) Received: from debian ([146.70.204.204]) by smtp.gmail.com with ESMTPSA id m37-20020a05600c3b2500b0041312c0cc45sm1208587wms.0.2024.03.07.05.29.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Mar 2024 05:30:09 -0800 (PST) Message-ID: Date: Thu, 7 Mar 2024 14:29:38 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: [PATCH net-next v2 4/4] net: gro: move L3 flush checks to tcp_gro_receive From: Richard Gobert To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, willemdebruijn.kernel@gmail.com, dsahern@kernel.org, shuah@kernel.org, idosch@nvidia.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <2ce1600b-e733-448b-91ac-9d0ae2b866a4@gmail.com> In-Reply-To: <2ce1600b-e733-448b-91ac-9d0ae2b866a4@gmail.com> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags, iph->id, ...) against all packets in a loop. These flush checks are relevant only to tcp flows, and as such they're used to determine whether the packets can be merged later in tcp_gro_receive. These checks are not relevant to UDP packets. Furthermore, they need to be done only once in tcp_gro_receive and only against the found p skb, since they only affect flush and not same_flow. Leveraging the previous commit in the series, in which correct network header offsets are saved for both outer and inner network headers - allowing these checks to be done only once, in tcp_gro_receive. As a result, NAPI_GRO_CB(p)->flush is not used at all. In addition - flush_id checks are more declarative and contained in inet_gro_flush, thus removing the need for flush_id in napi_gro_cb. This results in less parsing code for UDP flows and non-loop flush tests for TCP flows. For example, running 40 IP/UDP netperf connections: ./super_netperf.sh 40 -H 1.1.1.2 -t UDP_STREAM -l 120 Running perf top for 90s we can see that relatively less time is spent on inet_gro_receive when GRO is not coalescing UDP: net-next: 1.26% [kernel] [k] inet_gro_receive patch applied: 0.85% [kernel] [k] inet_gro_receive udpgro_bench.sh single connection GRO improvement: net-next: 0.76% [kernel] [k] inet_gro_receive patch applied: 0.61% [kernel] [k] inet_gro_receive Signed-off-by: Richard Gobert --- include/net/gro.h | 9 ++---- net/core/gro.c | 3 -- net/ipv4/af_inet.c | 36 --------------------- net/ipv4/tcp_offload.c | 73 ++++++++++++++++++++++++++++++++++-------- net/ipv6/ip6_offload.c | 11 ------- 5 files changed, 63 insertions(+), 69 deletions(-) diff --git a/include/net/gro.h b/include/net/gro.h index 923cbcc4c2fa..835cfc38a7b7 100644 --- a/include/net/gro.h +++ b/include/net/gro.h @@ -35,15 +35,15 @@ struct napi_gro_cb { /* This is non-zero if the packet cannot be merged with the new skb. */ u16 flush; - /* Save the IP ID here and check when we get to the transport layer */ - u16 flush_id; - /* Number of segments aggregated. */ u16 count; /* Used in ipv6_gro_receive() and foo-over-udp and esp-in-udp */ u16 proto; + /* used to support CHECKSUM_COMPLETE for tunneling protocols */ + __wsum csum; + /* Used in napi_gro_cb::free */ #define NAPI_GRO_FREE 1 #define NAPI_GRO_FREE_STOLEN_HEAD 2 @@ -83,9 +83,6 @@ struct napi_gro_cb { /* GRO is done by frag_list pointer chaining. */ u8 is_flist:1; ); - - /* used to support CHECKSUM_COMPLETE for tunneling protocols */ - __wsum csum; }; #define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb) diff --git a/net/core/gro.c b/net/core/gro.c index 7da3df2c634f..4128c16e76a2 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -332,8 +332,6 @@ static void gro_list_prepare(const struct list_head *head, list_for_each_entry(p, head, list) { unsigned long diffs; - NAPI_GRO_CB(p)->flush = 0; - if (hash != skb_get_hash_raw(p)) { NAPI_GRO_CB(p)->same_flow = 0; continue; @@ -472,7 +470,6 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff sizeof(u32))); /* Avoid slow unaligned acc */ *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0; NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb); - NAPI_GRO_CB(skb)->is_atomic = 1; NAPI_GRO_CB(skb)->count = 1; if (unlikely(skb_is_gso(skb))) { NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 09ab9ac4420b..a60301a43727 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1512,7 +1512,6 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) list_for_each_entry(p, head, list) { struct iphdr *iph2; - u16 flush_id; if (!NAPI_GRO_CB(p)->same_flow) continue; @@ -1529,43 +1528,8 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) NAPI_GRO_CB(p)->same_flow = 0; continue; } - - /* All fields must match except length and checksum. */ - NAPI_GRO_CB(p)->flush |= - (iph->ttl ^ iph2->ttl) | - (iph->tos ^ iph2->tos) | - ((iph->frag_off ^ iph2->frag_off) & htons(IP_DF)); - - NAPI_GRO_CB(p)->flush |= flush; - - /* We need to store of the IP ID check to be included later - * when we can verify that this packet does in fact belong - * to a given flow. - */ - flush_id = (u16)(id - ntohs(iph2->id)); - - /* This bit of code makes it much easier for us to identify - * the cases where we are doing atomic vs non-atomic IP ID - * checks. Specifically an atomic check can return IP ID - * values 0 - 0xFFFF, while a non-atomic check can only - * return 0 or 0xFFFF. - */ - if (!NAPI_GRO_CB(p)->is_atomic || - !(iph->frag_off & htons(IP_DF))) { - flush_id ^= NAPI_GRO_CB(p)->count; - flush_id = flush_id ? 0xFFFF : 0; - } - - /* If the previous IP ID value was based on an atomic - * datagram we can overwrite the value and ignore it. - */ - if (NAPI_GRO_CB(skb)->is_atomic) - NAPI_GRO_CB(p)->flush_id = flush_id; - else - NAPI_GRO_CB(p)->flush_id |= flush_id; } - NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF)); NAPI_GRO_CB(skb)->flush |= flush; /* Note : No need to call skb_gro_postpull_rcsum() here, diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index fde800179b2e..a9ea6c681fa6 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -178,6 +178,55 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb, return segs; } +static int inet_gro_flush(const struct iphdr *iph, const struct iphdr *iph2, + struct sk_buff *p, u32 outer) +{ + const u32 id = ntohl(*(__be32 *)&iph->id); + const u32 id2 = ntohl(*(__be32 *)&iph2->id); + const int flush_id = ntohs(id >> 16) - ntohs(id2 >> 16); + const u16 count = NAPI_GRO_CB(p)->count; + const u32 df = id & IP_DF; + u32 is_atomic; + int flush; + + /* All fields must match except length and checksum. */ + flush = (iph->ttl ^ iph2->ttl) | (iph->tos ^ iph2->tos) | (df ^ (id2 & IP_DF)); + + /* When we receive our second frame we can make a decision on if we + * continue this flow as an atomic flow with a fixed ID or if we use + * an incremdfenting ID. + */ + if (count == 1) { + is_atomic = df && flush_id == 0; + NAPI_GRO_CB(p)->is_atomic = is_atomic; + } else { + is_atomic = df && NAPI_GRO_CB(p)->is_atomic; + } + + /* Ignore outer IP ID value if based on atomic datagram. */ + outer = (outer && df) - 1; + is_atomic--; + + return flush | ((flush_id ^ (count & is_atomic)) & outer); +} + +static int ipv6_gro_flush(const struct ipv6hdr *iph, const struct ipv6hdr *iph2) +{ + /* */ + __be32 first_word = *(__be32 *)iph ^ *(__be32 *)iph2; + + /* Flush if Traffic Class fields are different. */ + return (first_word & htonl(0x0FF00000)) | + (__force __be32)(iph->hop_limit ^ iph2->hop_limit); +} + +static int gro_network_flush(const void *nh, const void *nh2, + struct sk_buff *p, u32 outer) +{ + return (((struct iphdr *)nh)->version == 6) ? ipv6_gro_flush(nh, nh2) : + inet_gro_flush(nh, nh2, p, outer); +} + struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) { struct sk_buff *pp = NULL; @@ -190,6 +239,8 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) unsigned int mss = 1; unsigned int hlen; unsigned int off; + unsigned int netoff_diff; + bool encap_mark; int flush = 1; int i; @@ -232,9 +283,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) goto out_check_final; found: - /* Include the IP ID check below from the inner most IP hdr */ - flush = NAPI_GRO_CB(p)->flush; - flush |= (__force int)(flags & TCP_FLAG_CWR); + flush = (__force int)(flags & TCP_FLAG_CWR); flush |= (__force int)((flags ^ tcp_flag_word(th2)) & ~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH)); flush |= (__force int)(th->ack_seq ^ th2->ack_seq); @@ -242,16 +291,14 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb) flush |= *(u32 *)((u8 *)th + i) ^ *(u32 *)((u8 *)th2 + i); - /* When we receive our second frame we can made a decision on if we - * continue this flow as an atomic flow with a fixed ID or if we use - * an incrementing ID. - */ - if (NAPI_GRO_CB(p)->flush_id != 1 || - NAPI_GRO_CB(p)->count != 1 || - !NAPI_GRO_CB(p)->is_atomic) - flush |= NAPI_GRO_CB(p)->flush_id; - else - NAPI_GRO_CB(p)->is_atomic = false; + encap_mark = NAPI_GRO_CB(skb)->encap_mark; + netoff_diff = off - skb_network_offset(skb); + for (i = 0; i <= encap_mark; i++) { + flush |= gro_network_flush(((void *)th) - netoff_diff, + ((void *)th2) - netoff_diff, + p, i != encap_mark); + netoff_diff = off - skb_inner_network_offset(skb); + } mss = skb_shinfo(p)->gso_size; diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 29601be9fa90..6e29ddfc0bc1 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -288,19 +288,8 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, nlen - sizeof(struct ipv6hdr))) goto not_same_flow; } - /* flush if Traffic Class fields are different */ - NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) | - (__force __be32)(iph->hop_limit ^ iph2->hop_limit)); - NAPI_GRO_CB(p)->flush |= flush; - - /* If the previous IP ID value was based on an atomic - * datagram we can overwrite the value and ignore it. - */ - if (NAPI_GRO_CB(skb)->is_atomic) - NAPI_GRO_CB(p)->flush_id = 0; } - NAPI_GRO_CB(skb)->is_atomic = true; NAPI_GRO_CB(skb)->flush |= flush; skb_gro_postpull_rcsum(skb, iph, nlen);