udp: use atomic_inc_not_zero_hint
UDP sockets refcount is usually 2, unless an incoming frame is going to
be queued in receive or backlog queue.
Using atomic_inc_not_zero_hint() permits to reduce latency, because
processor issues less memory transactions.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5e0a3a5..491ecd3 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -430,7 +430,7 @@
if (result) {
exact_match:
- if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL;
else if (unlikely(compute_score2(result, net, saddr, sport,
daddr, hnum, dif) < badness)) {
@@ -500,7 +500,7 @@
goto begin;
if (result) {
- if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+ if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
result = NULL;
else if (unlikely(compute_score(result, net, saddr, hnum, sport,
daddr, dport, dif) < badness)) {