fib: introduce fib_alias_accessed() helper
Perf tools session at NFWS 2010 pointed out a false sharing on struct
fib_alias that can be avoided pretty easily, if we set FA_S_ACCESSED bit
only if needed (ie : not already set)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
index 4f1aafd..43e1c59 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -335,7 +335,8 @@
if (!next_fi->fib_nh[0].nh_gw ||
next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
continue;
- fa->fa_state |= FA_S_ACCESSED;
+
+ fib_alias_accessed(fa);
if (fi == NULL) {
if (next_fi != res->fi)