net: Use a percpu_counter for orphan_count

Instead of using one atomic_t per protocol, use a percpu_counter
for "orphan_count", to reduce cache line contention on
heavy duty network servers. 

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 2 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index a2a3890959c4..5a3a151bd730 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -666,7 +666,7 @@ struct proto {
         unsigned int            obj_size;
         int                     slab_flags;
 
-        atomic_t                *orphan_count;
+        struct percpu_counter   *orphan_count;
 
         struct request_sock_ops *rsk_prot;
         struct timewait_sock_ops *twsk_prot;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index cbca3b8a133d..de1e91d959b8 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -46,7 +46,7 @@
 
 extern struct inet_hashinfo tcp_hashinfo;
 
-extern atomic_t tcp_orphan_count;
+extern struct percpu_counter tcp_orphan_count;
 extern void tcp_time_wait(struct sock *sk, int state, int timeo);
 
 #define MAX_TCP_HEADER  (128 + MAX_HEADER)