[NET]: move struct proto_ops to const
I noticed that some of 'struct proto_ops' used in the kernel may share
a cache line used by locks or other heavily modified data. (default
linker alignement is 32 bytes, and L1_CACHE_LINE is 64 or 128 at
least)
This patch makes sure a 'struct proto_ops' can be declared as const,
so that all cpus can share all parts of it without false sharing.
This is not mandatory : a driver can still use a read/write structure
if it needs to (and eventually a __read_mostly)
I made a global stubstitute to change all existing occurences to make
them const.
This should reduce the possibility of false sharing on SMP, and
speedup some socket system calls.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/wanrouter/af_wanpipe.c b/net/wanrouter/af_wanpipe.c
index 59fec59..67948bf 100644
--- a/net/wanrouter/af_wanpipe.c
+++ b/net/wanrouter/af_wanpipe.c
@@ -181,7 +181,7 @@
#endif
static int sk_count;
-extern struct proto_ops wanpipe_ops;
+extern const struct proto_ops wanpipe_ops;
static unsigned long find_free_critical;
static void wanpipe_unlink_driver(struct sock *sk);
@@ -2546,7 +2546,7 @@
return 0;
}
-struct proto_ops wanpipe_ops = {
+const struct proto_ops wanpipe_ops = {
.family = PF_WANPIPE,
.owner = THIS_MODULE,
.release = wanpipe_release,