net: Embed hh_cache inside of struct neighbour.
Now that there is a one-to-one correspondance between neighbour
and hh_cache entries, we no longer need:
1) dynamic allocation
2) attachment to dst->hh
3) refcounting
Initialization of the hh_cache entry is indicated by hh_len
being non-zero, and such initialization is always done with
the neighbour's lock held as a writer.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7538237..5ccc0cb 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -252,14 +252,7 @@
netdev_hw_addr_list_for_each(ha, &(dev)->mc)
struct hh_cache {
- atomic_t hh_refcnt; /* number of users */
-/*
- * 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.
- */
- u16 hh_len ____cacheline_aligned_in_smp;
+ u16 hh_len;
u16 __pad;
int (*hh_output)(struct sk_buff *skb);
seqlock_t hh_lock;
@@ -273,12 +266,6 @@
unsigned long hh_data[HH_DATA_ALIGN(LL_MAX_HEADER) / sizeof(long)];
};
-static inline void hh_cache_put(struct hh_cache *hh)
-{
- if (atomic_dec_and_test(&hh->hh_refcnt))
- kfree(hh);
-}
-
/* Reserve HH_DATA_MOD byte aligned hard_header_len, but at least that much.
* Alternative is:
* dev->hard_header_len ? (dev->hard_header_len +
diff --git a/include/net/dst.h b/include/net/dst.h
index e12ddfb..0dd7ccb 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -38,7 +38,6 @@
unsigned long expires;
struct dst_entry *path;
struct neighbour *neighbour;
- struct hh_cache *hh;
#ifdef CONFIG_XFRM
struct xfrm_state *xfrm;
#else
@@ -47,6 +46,14 @@
int (*input)(struct sk_buff*);
int (*output)(struct sk_buff*);
+ int flags;
+#define DST_HOST 0x0001
+#define DST_NOXFRM 0x0002
+#define DST_NOPOLICY 0x0004
+#define DST_NOHASH 0x0008
+#define DST_NOCACHE 0x0010
+#define DST_NOCOUNT 0x0020
+
short error;
short obsolete;
unsigned short header_len; /* more space at head required */
@@ -62,7 +69,7 @@
* (L1_CACHE_SIZE would be too much)
*/
#ifdef CONFIG_64BIT
- long __pad_to_align_refcnt[1];
+ long __pad_to_align_refcnt[2];
#endif
/*
* __refcnt wants to be on a different cache line from
@@ -71,13 +78,6 @@
atomic_t __refcnt; /* client references */
int __use;
unsigned long lastuse;
- int flags;
-#define DST_HOST 0x0001
-#define DST_NOXFRM 0x0002
-#define DST_NOPOLICY 0x0004
-#define DST_NOHASH 0x0008
-#define DST_NOCACHE 0x0010
-#define DST_NOCOUNT 0x0020
union {
struct dst_entry *next;
struct rtable __rcu *rt_next;
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 6fe8c2c..bd8f9f0 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -108,7 +108,7 @@
__u8 dead;
seqlock_t ha_lock;
unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
- struct hh_cache *hh;
+ struct hh_cache hh;
int (*output)(struct sk_buff *skb);
const struct neigh_ops *ops;
struct rcu_head rcu;