[NET]: Implement SKB fast cloning.
Protocols that make extensive use of SKB cloning,
for example TCP, eat at least 2 allocations per
packet sent as a result.
To cut the kmalloc() count in half, we implement
a pre-allocation scheme wherein we allocate
2 sk_buff objects in advance, then use a simple
reference count to free up the memory at the
correct time.
Based upon an initial patch by Thomas Graf and
suggestions from Herbert Xu.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index db10335..42edce6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -162,6 +162,13 @@
u32 off_usec;
};
+
+enum {
+ SKB_FCLONE_UNAVAILABLE,
+ SKB_FCLONE_ORIG,
+ SKB_FCLONE_CLONE,
+};
+
/**
* struct sk_buff - socket buffer
* @next: Next buffer in list
@@ -255,7 +262,8 @@
ip_summed:2,
nohdr:1,
nfctinfo:3;
- __u8 pkt_type;
+ __u8 pkt_type:3,
+ fclone:2;
__be16 protocol;
void (*destructor)(struct sk_buff *skb);
@@ -295,8 +303,20 @@
#include <asm/system.h>
extern void __kfree_skb(struct sk_buff *skb);
-extern struct sk_buff *alloc_skb(unsigned int size,
- unsigned int __nocast priority);
+extern struct sk_buff *__alloc_skb(unsigned int size,
+ unsigned int __nocast priority, int fclone);
+static inline struct sk_buff *alloc_skb(unsigned int size,
+ unsigned int __nocast priority)
+{
+ return __alloc_skb(size, priority, 0);
+}
+
+static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
+ unsigned int __nocast priority)
+{
+ return __alloc_skb(size, priority, 1);
+}
+
extern struct sk_buff *alloc_skb_from_cache(kmem_cache_t *cp,
unsigned int size,
unsigned int __nocast priority);