[AF_UNIX]: Convert to use a spinlock instead of rwlock
From: Benjamin LaHaise <bcrl@kvack.org>
In af_unix, a rwlock is used to protect internal state. At least on my
P4 with HT it is faster to use a spinlock due to the simpler memory
barrier used to unlock. This patch raises bw_unix to ~690K/s.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 7d3fe6a..1ddd36d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -564,7 +564,7 @@
u = unix_sk(sk);
u->dentry = NULL;
u->mnt = NULL;
- rwlock_init(&u->lock);
+ spin_lock_init(&u->lock);
atomic_set(&u->inflight, sock ? 0 : -1);
init_MUTEX(&u->readsem); /* single task reading lock */
init_waitqueue_head(&u->peer_wait);