net: Use a percpu_counter for sockets_allocated

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

Note : We revert commit (248969ae31e1b3276fc4399d67ce29a5d81e6fd9
net: af_unix can make unix_nr_socks visbile in /proc),
since it is not anymore used after sock_prot_inuse_add() addition

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

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 731789bb499f..4944b47ad628 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -55,7 +55,8 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
         seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %d\n",
                    sock_prot_inuse_get(net, &tcp_prot),
                    atomic_read(&tcp_orphan_count),
-                   tcp_death_row.tw_count, atomic_read(&tcp_sockets_allocated),
+                   tcp_death_row.tw_count,
+                   (int)percpu_counter_sum_positive(&tcp_sockets_allocated),
                    atomic_read(&tcp_memory_allocated));
         seq_printf(seq, "UDP: inuse %d mem %d\n",
                    sock_prot_inuse_get(net, &udp_prot),