netns: reorder fields in struct net
In a network bench, I noticed an unfortunate false sharing between
'loopback_dev' and 'count' fields in "struct net".
'count' is written each time a socket is created or destroyed, while
loopback_dev might be often read in routing code.
Move loopback_dev in a read mostly section of "struct net"
Note: struct netns_xfrm is cache line aligned on SMP.
(It contains a "struct dst_ops")
Move it at the end to avoid holes, and reduce sizeof(struct net) by 128
bytes on ia32.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
index 74f119a..748f91f 100644
--- a/include/net/netns/xfrm.h
+++ b/include/net/netns/xfrm.h
@@ -43,10 +43,6 @@
unsigned int policy_count[XFRM_POLICY_MAX * 2];
struct work_struct policy_hash_work;
- struct dst_ops xfrm4_dst_ops;
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
- struct dst_ops xfrm6_dst_ops;
-#endif
struct sock *nlsk;
struct sock *nlsk_stash;
@@ -58,6 +54,11 @@
#ifdef CONFIG_SYSCTL
struct ctl_table_header *sysctl_hdr;
#endif
+
+ struct dst_ops xfrm4_dst_ops;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+ struct dst_ops xfrm6_dst_ops;
+#endif
};
#endif