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authorEric Dumazet <edumazet@google.com>2014-09-15 04:19:51 -0700
committerDavid S. Miller <davem@davemloft.net>2014-09-15 14:41:07 -0400
commite11ecddf5128011c936cc5360780190cbc901fdc (patch)
treed7723697219a35e66ae7c1dab9e85832a0d19e11 /net/ipv6/tcp_ipv6.c
parent13bb5180e82349d9fcfa11cd17b3c1e7b558a902 (diff)
tcp: use TCP_SKB_CB(skb)->tcp_flags in input path
Input path of TCP do not currently uses TCP_SKB_CB(skb)->tcp_flags, which is only used in output path. tcp_recvmsg(), looks at tcp_hdr(skb)->syn for every skb found in receive queue, and its unfortunate because this bit is located in a cache line right before the payload. We can simplify TCP by copying tcp flags into TCP_SKB_CB(skb)->tcp_flags. This patch does so, and avoids the cache line miss in tcp_recvmsg() Following patches will - allow a segment with FIN being coalesced in tcp_try_coalesce() - simplify tcp_collapse() by not copying the headers. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
-rw-r--r--net/ipv6/tcp_ipv6.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1835480336ac..de51a88bec6f 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1415,6 +1415,7 @@ static int tcp_v6_rcv(struct sk_buff *skb)
TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
skb->len - th->doff*4);
TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
+ TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
TCP_SKB_CB(skb)->tcp_tw_isn = 0;
TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
TCP_SKB_CB(skb)->sacked = 0;

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