Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6

[safe/jmp/linux-2.6] / include / linux / netdevice.h

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 949eada..6be767c 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -30,6 +30,7 @@
 #include <linux/if_packet.h>
 
 #ifdef __KERNEL__
+#include <linux/timer.h>
 #include <asm/atomic.h>
 #include <asm/cache.h>
 #include <asm/byteorder.h>
@@ -192,13 +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