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 +1,28 @@
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -854,25 +854,7 @@ void netlink_detachskb(struct sock *sk,
static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
{
- int delta;
-
skb_orphan(skb);
-
- delta = skb->end - skb->tail;
- if (delta * 2 < skb->truesize)
- return skb;
-
- if (skb_shared(skb)) {
- struct sk_buff *nskb = skb_clone(skb, allocation);
- if (!nskb)
- return skb;
- kfree_skb(skb);
- skb = nskb;
- }
-
- if (!pskb_expand_head(skb, 0, -delta, allocation))
- skb->truesize -= delta;
-
return skb;
}

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@ -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,

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@ -0,0 +1,11 @@
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1558,7 +1558,7 @@ static inline int pskb_network_may_pull(
* NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
*/
#ifndef NET_SKB_PAD
-#define NET_SKB_PAD max(32, L1_CACHE_BYTES)
+#define NET_SKB_PAD max(48, L1_CACHE_BYTES)
#endif
extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);