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_semantics.c b/net/ipv4/fib_semantics.c
index 6734c9c..3e0da3e 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -901,7 +901,7 @@
if (fa->fa_scope < flp->fl4_scope)
continue;
- fa->fa_state |= FA_S_ACCESSED;
+ fib_alias_accessed(fa);
err = fib_props[fa->fa_type].error;
if (err == 0) {