From patchwork Wed Apr 10 15:34:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Gobert X-Patchwork-Id: 13624764 X-Patchwork-Delegate: kuba@kernel.org 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 0ADE8176FC8; Wed, 10 Apr 2024 15:35:47 +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=1712763350; cv=none; b=G7tH9kIXkJt4mQqntJze2j0GR61tDCIq9dB5BPj6nkKYHXcYT0Nwot6BmYYRTST+X/WJ2X6krkk3QS24i2Sv7cJUTimHcsd0byhW0kc/rtbSCADRbQgHmgzRgtmIkApzjHGLiy31dC774y2DVkmdIdULTqTG2T/B19zNKx/dTho= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712763350; c=relaxed/simple; bh=Hr8YHaTGoei0aoyswr+qYCaHrLJXYO3y1I6JtRFpITM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=GWu7TSVRBqFtNO3NhS/Yg/Q/CEz0XSACoXQ4YfP3u1KLatcJuQsd7TRGnWrfUa6HYAuHi1b30145DodJQsXrDnOwp4i81BOWp+eVvvhu+5IQ9oV+PxIeK9Tgxjkl+IdjZJZ+tHYfDs5pzMbpi9IApwvfQDxdhn68EQogD9C4NmE= 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=dACZU0kH; 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="dACZU0kH" Received: by mail-wm1-f50.google.com with SMTP id 5b1f17b1804b1-416422e2acbso22711555e9.1; Wed, 10 Apr 2024 08:35:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1712763346; x=1713368146; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=/pudm4Qj5I3CWyz7oEzjDZpZS7D4UqigIUQcMjBXv8Q=; b=dACZU0kHgRumA94XMsdKP+aONtozt5e0nccS8cLUaAMVYXG3kd6R9KdQfn3qbPMj8N TAdsUpKew9FZ89eRxU/pJV0wGnTUHP8a97rvchwkQXtvi1ppw2efBN7H52qtwkG2H5SI o/zU0FjtyCRB7pE3f++wRhZbLbwEuIcY0WP8PaKI8BLp5jqVThkj8DOZm4lz872Rltcl DrtS2j3resaWQkhKpjHFiTdf87F1/hlL2gHNltKcdqZuiqBHX+w7/DLoZGb9xO2nB4nH 7TVnhMotD5aaIxjka/d7NDujhd6Us8GPx34x+G9xqpRM8SOYcVJJonJmniTDTvjyaMKR 4/lA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712763346; x=1713368146; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/pudm4Qj5I3CWyz7oEzjDZpZS7D4UqigIUQcMjBXv8Q=; b=OMYHATLSz0UkD8rPrkdazsoWOSEUIn+agmK1HcayM9k0uHqc3VShLQH3MmaoTwQNI+ TK5t2a1pXfGItY7SNqNOIOP6TTx09Wdqn9IbQRJnsebmgcYG4lX71i94X/nDsx6ayqOE d3nhM43bw/YuFYceRJ/ZktirjNQhPVGk+CPQJ+HVnlfgKUIY2i9ap7A6nbGJL5c+rK/Q sLpnxACejd/8M2y4p3bf6RpkRuCsCgd08zKNOq0tvx3JEmD8M5Rz550P4SX0p1CTYIGG zT0w995GnWpBr/i50FiDe3ZYG9PBDNnz7z9S5EtcIQzlicJ7dsQsNNNdwMmtqsS9R3x3 ewog== X-Forwarded-Encrypted: i=1; AJvYcCVJ+LBNJnW3wx/WiO3SZDRXNB0y4QL7Cgu9VV8bbGMCXSs3QH1gjHLJvYl+4oOVRA8eqSw1LmDU+94PstFs7KrJP+g2Vz+d/Sbn23f5YVIV/uGg/S8QbHZKuu5PSjw3GG0QVXXKfzIvFCRRPg+dhUxZuUtRl2iI6iO1pqRLi6uEtzLwxval X-Gm-Message-State: AOJu0YxfHpqNGoDfjwC3byTuWNPsNffLZtq7/C84oJ/ziPhOOncbpvv8 a8NZdgjMNqtxQ51XSz/TOKuVN8YvGHyhVtH7k7FG/cM6QVRAzDqFV3MU0dIQ X-Google-Smtp-Source: AGHT+IEcT2y6TucCnrc7G1/FcafJ6/+NkPKgE76AKprrrCrG+mKW6tYWsJVBdVL8X9+8AuZ0knLMmw== X-Received: by 2002:a05:600c:1c04:b0:416:350c:db48 with SMTP id j4-20020a05600c1c0400b00416350cdb48mr10696wms.9.1712763346270; Wed, 10 Apr 2024 08:35:46 -0700 (PDT) Received: from localhost ([146.70.204.204]) by smtp.gmail.com with ESMTPSA id d2-20020a05600c34c200b004155387c08esm2625240wmq.27.2024.04.10.08.35.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Apr 2024 08:35:46 -0700 (PDT) From: Richard Gobert To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, willemdebruijn.kernel@gmail.com, shuah@kernel.org, dsahern@kernel.org, aduyck@mirantis.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Richard Gobert Subject: [PATCH net-next v6 5/6] net: gro: move L3 flush checks to tcp_gro_receive and udp_gro_receive_segment Date: Wed, 10 Apr 2024 17:34:22 +0200 Message-Id: <20240410153423.107381-6-richardbgobert@gmail.com> In-Reply-To: <20240410153423.107381-1-richardbgobert@gmail.com> References: <20240410153423.107381-1-richardbgobert@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags, iph->id, ...) against all packets in a loop. These flush checks are used currently only in tcp flows in GRO. These checks 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. To make sure results are not within noise range - I've made netfilter drop all TCP packets, and measured CPU performance in GRO (in this case GRO is responsible for about 50% of the CPU utilization). gro_network_flush is compiled inline to tcp_gro_receive. perf top while replaying 64 parallel IP/TCP streams merging in GRO net-next: 6.94% [kernel] [k] inet_gro_receive 3.02% [kernel] [k] tcp_gro_receive patch applied: 4.27% [kernel] [k] tcp_gro_receive 4.22% [kernel] [k] inet_gro_receive perf top while replaying 64 parallel IP/IP/TCP streams merging in GRO (same results for any encapsulation, in this case inet_gro_receive is top offender in net-next) net-next: 10.09% [kernel] [k] inet_gro_receive 2.08% [kernel] [k] tcp_gro_receive patch applied: 6.97% [kernel] [k] inet_gro_receive 3.68% [kernel] [k] tcp_gro_receive perf top -g while running 64 IP/UDP netperf connections NOT merging in GRO (udp_gro_receive is included because of -g, in this case GRO is just overhead) net-next: 1.26% [kernel] [k] inet_gro_receive patch applied: 0.85% [kernel] [k] inet_gro_receive Signed-off-by: Richard Gobert --- include/net/gro.h | 66 ++++++++++++++++++++++++++++++++++++++---- net/core/gro.c | 4 --- net/ipv4/af_inet.c | 41 +------------------------- net/ipv4/tcp_offload.c | 15 ++-------- net/ipv4/udp_offload.c | 16 +++------- net/ipv6/ip6_offload.c | 11 ------- 6 files changed, 67 insertions(+), 86 deletions(-) diff --git a/include/net/gro.h b/include/net/gro.h index a1cc8e8c2ebd..c1f80f1156d6 100644 --- a/include/net/gro.h +++ b/include/net/gro.h @@ -36,15 +36,15 @@ 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 @@ -85,9 +85,6 @@ struct napi_gro_cb { u8 is_flist:1; ); - /* used to support CHECKSUM_COMPLETE for tunneling protocols */ - __wsum csum; - /* L3 offsets */ union { struct { @@ -443,6 +440,63 @@ static inline __wsum ip6_gro_compute_pseudo(const struct sk_buff *skb, skb_gro_len(skb), proto, 0)); } +static inline int inet_gro_flush(const struct iphdr *iph, const struct iphdr *iph2, + struct sk_buff *p, bool outer) +{ + const u32 id = ntohl(*(__be32 *)&iph->id); + const u32 id2 = ntohl(*(__be32 *)&iph2->id); + const u16 flush_id = (id >> 16) - (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)); + + if (outer && df) + return flush; + + /* 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 incrementing ID. + */ + NAPI_GRO_CB(p)->is_atomic |= (count == 1 && df && flush_id == 0); + is_atomic = (df && NAPI_GRO_CB(p)->is_atomic) - 1; + + return flush | (flush_id ^ (count & is_atomic)); +} + +static inline 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 inline int gro_network_flush(const void *th, const void *th2, struct sk_buff *p, int off) +{ + const bool encap_mark = NAPI_GRO_CB(p)->encap_mark; + int flush = 0; + int i; + + for (i = 0; i <= encap_mark; i++) { + const u16 diff = off - NAPI_GRO_CB(p)->network_offsets[i]; + const void *nh = th - diff; + const void *nh2 = th2 - diff; + + if (((struct iphdr *)nh)->version == 6) + flush |= ipv6_gro_flush(nh, nh2); + else + flush |= inet_gro_flush(nh, nh2, p, i != encap_mark); + } + + return flush; +} + int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb); /* Pass the currently batched GRO_NORMAL SKBs up to the stack. */ diff --git a/net/core/gro.c b/net/core/gro.c index b2156e6cc4ad..3bfdfefe4a24 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -89,7 +89,6 @@ void dev_remove_offload(struct packet_offload *po) } EXPORT_SYMBOL(dev_remove_offload); - int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) { struct skb_shared_info *pinfo, *skbinfo = skb_shinfo(skb); @@ -330,8 +329,6 @@ 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; @@ -471,7 +468,6 @@ 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 6546bf376b24..af094aecf38c 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1481,7 +1481,6 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) struct sk_buff *p; unsigned int hlen; unsigned int off; - unsigned int id; int flush = 1; int proto; @@ -1507,13 +1506,10 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) goto out; NAPI_GRO_CB(skb)->proto = proto; - id = ntohl(*(__be32 *)&iph->id); - flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF)); - id >>= 16; + flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (ntohl(*(__be32 *)&iph->id) & ~IP_DF)); list_for_each_entry(p, head, list) { struct iphdr *iph2; - u16 flush_id; if (!NAPI_GRO_CB(p)->same_flow) continue; @@ -1530,43 +1526,8 @@ 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 7f045b881dd4..1b10ab3b0f6a 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -232,9 +232,7 @@ 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 +240,7 @@ 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; + flush |= gro_network_flush(th, th2, p, off); mss = skb_shinfo(p)->gso_size; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index ad4c88fe7d15..c5a5155904cf 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -466,12 +466,12 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head, struct sk_buff *skb) { struct udphdr *uh = udp_gro_udphdr(skb); + int off = skb_gro_offset(skb); struct sk_buff *pp = NULL; struct udphdr *uh2; struct sk_buff *p; unsigned int ulen; int ret = 0; - int flush; /* requires non zero csum, for symmetry with GSO */ if (!uh->check) { @@ -529,17 +529,9 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head, skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); - flush = NAPI_GRO_CB(p)->flush; - - 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; - - if (flush || skb_gro_receive(p, skb)) - ret = 1; + ret = gro_network_flush(uh, uh2, p, off); + if (!ret) + ret = skb_gro_receive(p, skb); } } diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index ba41939537f2..c9a6bc1afc9a 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);