[PATCH v2 net-next 1/3] net: Add cache alignment in sock_common for socket lookup fields

[Tom Herbert <tom@herbertland.com>]

Use ____cacheline_aligned_in_smp to keep the fields used on socket
lookup in their own cachelines. These are read only fields and will
be often accessed on accross CPUs (would be very common with
SO_REUSEPORT for instance).

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/net/sock.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 26c1c31..bcf6114 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -211,7 +211,13 @@ struct sock_common {
 		struct hlist_node	skc_node;
 		struct hlist_nulls_node skc_nulls_node;
 	};
-	int			skc_tx_queue_mapping;
+
+	/* Cachelines above this point are read mostly and are used in socket
+	 * lookup.
+	 */
+	int			skc_tx_queue_mapping
+				____cacheline_aligned_in_smp;
+
 	atomic_t		skc_refcnt;
 	/* private: */
 	int                     skc_dontcopy_end[0];
-- 
1.8.1