improve the skb padding performance change to avoid unnecessary reallocations in the routing code

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@15761 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 44 insertions, 4 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.29/205-skb_padding.patch b/target/linux/generic-2.6/patches-2.6.29/205-skb_padding.patch
index c11bffe550..ff05b8d930 100644
--- a/target/linux/generic-2.6/patches-2.6.29/205-skb_padding.patch
+++ b/target/linux/generic-2.6/patches-2.6.29/205-skb_padding.patch
@@ -1,16 +1,56 @@
 --- a/include/linux/skbuff.h
 +++ b/include/linux/skbuff.h
-@@ -1306,9 +1306,12 @@
+@@ -1306,11 +1306,18 @@ static inline int skb_network_offset(con
   *
   * Various parts of the networking layer expect at least 16 bytes of
   * headroom, you should not reduce this.
 + *
 + * This has been changed to 64 to acommodate for routing between ethernet
-+ * and wireless
++ * and wireless, but only for new allocations
   */
  #ifndef NET_SKB_PAD
--#define NET_SKB_PAD	16
-+#define NET_SKB_PAD	64
+ #define NET_SKB_PAD	16
  #endif
  
++#ifndef NET_SKB_PAD_ALLOC
++#define NET_SKB_PAD_ALLOC	64
++#endif
++
  extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
+ 
+ static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
+@@ -1400,9 +1407,9 @@ static inline void __skb_queue_purge(str
+ static inline struct sk_buff *__dev_alloc_skb(unsigned int length,
+ 					      gfp_t gfp_mask)
+ {
+-	struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD, gfp_mask);
++	struct sk_buff *skb = alloc_skb(length + NET_SKB_PAD_ALLOC, gfp_mask);
+ 	if (likely(skb))
+-		skb_reserve(skb, NET_SKB_PAD);
++		skb_reserve(skb, NET_SKB_PAD_ALLOC);
+ 	return skb;
+ }
+ 
+@@ -1475,7 +1482,7 @@ static inline int __skb_cow(struct sk_bu
+ 		delta = headroom - skb_headroom(skb);
+ 
+ 	if (delta || cloned)
+-		return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,
++		return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD_ALLOC), 0,
+ 					GFP_ATOMIC);
+ 	return 0;
+ }
+--- a/net/core/skbuff.c
++++ b/net/core/skbuff.c
+@@ -320,9 +320,9 @@ struct sk_buff *__netdev_alloc_skb(struc
+ 	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;
+ 	struct sk_buff *skb;
+ 
+-	skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask, 0, node);
++	skb = __alloc_skb(length + NET_SKB_PAD_ALLOC, gfp_mask, 0, node);
+ 	if (likely(skb)) {
+-		skb_reserve(skb, NET_SKB_PAD);
++		skb_reserve(skb, NET_SKB_PAD_ALLOC);
+ 		skb->dev = dev;
+ 	}
+ 	return skb;