In the udp_sock struct, the 'forward_deficit' and 'pcflag' fields
share the same cacheline. While the first is dirtied by
udp_recvmsg, the latter is read, possibly several times, by the
bottom half processing to discriminate between udp and udplite
sockets.
With this patch, sk->sk_protocol is used to check is the socket is
really an udplite one, avoiding some cache misses per
packet and improving the performance under udp_flood with
small packet up to 10%.
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
include/linux/udp.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index c0f5308..6cb4061 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -115,6 +115,6 @@ static inline bool udp_get_no_check6_rx(struct sock *sk)
#define udp_portaddr_for_each_entry_rcu(__sk, list) \
hlist_for_each_entry_rcu(__sk, list, __sk_common.skc_portaddr_node)
-#define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
+#define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
#endif /* _LINUX_UDP_H */
--
2.9.3
