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>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 3df339e3e363..cc4e6d27dedc 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -65,7 +65,7 @@ static void tcp_write_err(struct sock *sk)
 static int tcp_out_of_resources(struct sock *sk, int do_reset)
 {
         struct tcp_sock *tp = tcp_sk(sk);
-        int orphans = atomic_read(&tcp_orphan_count);
+        int orphans = percpu_counter_read_positive(&tcp_orphan_count);
 
         /* If peer does not open window for long time, or did not transmit
          * anything for long time, penalize it. */