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-rw-r--r--include/linux/netdevice.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 631cec4ff5e..6be767c76b3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -193,7 +193,14 @@ 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
*/