netlink: move nl_table in read_mostly section
authorEric Dumazet <edumazet@google.com>
Wed, 13 May 2015 00:24:50 +0000 (17:24 -0700)
committerDavid S. Miller <davem@davemloft.net>
Thu, 14 May 2015 21:49:06 +0000 (17:49 -0400)
commit91dd93f956b9ea9ecf47fd4b9acd2d2e7f980303
tree1144107d6ac2f98703f314450ebb866baf6bcbad
parentbe346ffaad9bc354075fba5cd009fc4519abdd64
netlink: move nl_table in read_mostly section

netlink sockets creation and deletion heavily modify nl_table_users
and nl_table_lock.

If nl_table is sharing one cache line with one of them, netlink
performance is really bad on SMP.

ffffffff81ff5f00 B nl_table
ffffffff81ff5f0c b nl_table_users

Putting nl_table in read_mostly section increased performance
of my open/delete netlink sockets test by about 80 %

This came up while diagnosing a getaddrinfo() problem.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/netlink/af_netlink.c