1 files changed, 9 insertions, 2 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c57088f575a3..6be767c76b37 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -193,13 +193,20 @@ struct hh_cache
 {
         struct hh_cache *hh_next;       /* Next entry                        */
         atomic_t        hh_refcnt;      /* number of users                   */
-        __be16          hh_type;        /* protocol identifier, f.e ETH_P_IP
+/*
+ * We want hh_output, hh_len, hh_lock and hh_data be a in a separate
+ * cache line on SMP.
+ * They are mostly read, but hh_refcnt may be changed quite frequently,
+ * incurring cache line ping pongs.
+ */
+        __be16          hh_type ____cacheline_aligned_in_smp;
+                                        /* protocol identifier, f.e ETH_P_IP
                                          *  NOTE:  For VLANs, this will be the
                                          *  encapuslated type. --BLG
                                          */
         u16             hh_len;         /* length of header */
         int             (*hh_output)(struct sk_buff *skb);
-        rwlock_t        hh_lock;
+        seqlock_t       hh_lock;
 
         /* cached hardware header; allow for machine alignment needs.        */
 #define HH_DATA_MOD     16