kernel: add a few patches for avoiding unnecessary skb reallocations - significantly improves ethernet<->wireless performance with mac80211 based drivers

SVN-Revision: 31886
This commit is contained in:
Felix Fietkau
2012-05-27 14:43:58 +00:00
parent ec7786c2ec
commit 6f89cffc9a
3 changed files with 59 additions and 0 deletions

View File

@@ -0,0 +1,20 @@
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1850,12 +1850,15 @@ static inline int skb_clone_writable(con
static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
int cloned)
{
+ unsigned int alloc_headroom = headroom;
int delta = 0;
if (headroom < NET_SKB_PAD)
- headroom = NET_SKB_PAD;
- if (headroom > skb_headroom(skb))
+ alloc_headroom = NET_SKB_PAD;
+ if (headroom > skb_headroom(skb) ||
+ (cloned && alloc_headroom > skb_headroom(skb))) {
delta = headroom - skb_headroom(skb);
+ }
if (delta || cloned)
return pskb_expand_head(skb, ALIGN(delta, NET_SKB_PAD), 0,