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Diffstat (limited to 'include/net/dst.h')
-rw-r--r--include/net/dst.h30
1 files changed, 22 insertions, 8 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
index d67fda89cd0f..78884429deed 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -16,6 +16,7 @@
#include <linux/bug.h>
#include <linux/jiffies.h>
#include <linux/refcount.h>
+#include <linux/rcuref.h>
#include <net/neighbour.h>
#include <asm/processor.h>
#include <linux/indirect_call_wrapper.h>
@@ -61,23 +62,36 @@ struct dst_entry {
unsigned short trailer_len; /* space to reserve at tail */
/*
- * __refcnt wants to be on a different cache line from
+ * __rcuref wants to be on a different cache line from
* input/output/ops or performance tanks badly
*/
#ifdef CONFIG_64BIT
- atomic_t __refcnt; /* 64-bit offset 64 */
+ rcuref_t __rcuref; /* 64-bit offset 64 */
#endif
int __use;
unsigned long lastuse;
- struct lwtunnel_state *lwtstate;
struct rcu_head rcu_head;
short error;
short __pad;
__u32 tclassid;
#ifndef CONFIG_64BIT
- atomic_t __refcnt; /* 32-bit offset 64 */
+ struct lwtunnel_state *lwtstate;
+ rcuref_t __rcuref; /* 32-bit offset 64 */
#endif
netdevice_tracker dev_tracker;
+
+ /*
+ * Used by rtable and rt6_info. Moves lwtstate into the next cache
+ * line on 64bit so that lwtstate does not cause false sharing with
+ * __rcuref under contention of __rcuref. This also puts the
+ * frequently accessed members of rtable and rt6_info out of the
+ * __rcuref cache line.
+ */
+ struct list_head rt_uncached;
+ struct uncached_list *rt_uncached_list;
+#ifdef CONFIG_64BIT
+ struct lwtunnel_state *lwtstate;
+#endif
};
struct dst_metrics {
@@ -225,10 +239,10 @@ static inline void dst_hold(struct dst_entry *dst)
{
/*
* If your kernel compilation stops here, please check
- * the placement of __refcnt in struct dst_entry
+ * the placement of __rcuref in struct dst_entry
*/
- BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
- WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
+ BUILD_BUG_ON(offsetof(struct dst_entry, __rcuref) & 63);
+ WARN_ON(!rcuref_get(&dst->__rcuref));
}
static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
@@ -292,7 +306,7 @@ static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb
*/
static inline bool dst_hold_safe(struct dst_entry *dst)
{
- return atomic_inc_not_zero(&dst->__refcnt);
+ return rcuref_get(&dst->__rcuref);
}
/**