From d21dbdfe0afb5195607d207f894fe86d5b322d46 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 18 Nov 2016 17:18:03 -0800 Subject: [PATCH] udp: avoid one cache line miss in recvmsg() UDP_SKB_CB(skb)->partial_cov is located at offset 66 in skb, requesting a cold cache line being read in cpu cache. We can avoid this cache line miss for UDP sockets, as partial_cov has a meaning only for UDPLite. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/udp.c | 3 ++- net/ipv6/udp.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e1fc0116e8d5..b949770fdc08 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1389,7 +1389,8 @@ try_again: * coverage checksum (UDP-Lite), do it before the copy. */ - if (copied < ulen || UDP_SKB_CB(skb)->partial_cov || peeking) { + if (copied < ulen || peeking || + (is_udplite && UDP_SKB_CB(skb)->partial_cov)) { checksum_valid = !udp_lib_checksum_complete(skb); if (!checksum_valid) goto csum_copy_err; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 4f99417d9b40..8fd4d89380b8 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -363,7 +363,8 @@ try_again: * coverage checksum (UDP-Lite), do it before the copy. */ - if (copied < ulen || UDP_SKB_CB(skb)->partial_cov || peeking) { + if (copied < ulen || peeking || + (is_udplite && UDP_SKB_CB(skb)->partial_cov)) { checksum_valid = !udp_lib_checksum_complete(skb); if (!checksum_valid) goto csum_copy_err; -- 2.20.1