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authorFelix Fietkau <nbd@openwrt.org>2012-05-29 03:35:08 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-29 17:30:08 -0400
commit617c8c11236716dcbda877e764b7bf37c6fd8063 (patch)
tree78211c03e4e80eb1ea448c45139ce07534ccd238 /include/linux/skbuff.h
parent79fba9f51755c704c0a7d7b7f0df10874dc0a744 (diff)
skb: avoid unnecessary reallocations in __skb_cow
At the beginning of __skb_cow, headroom gets set to a minimum of NET_SKB_PAD. This causes unnecessary reallocations if the buffer was not cloned and the headroom is just below NET_SKB_PAD, but still more than the amount requested by the caller. This was showing up frequently in my tests on VLAN tx, where vlan_insert_tag calls skb_cow_head(skb, VLAN_HLEN). Locally generated packets should have enough headroom, and for forward paths, we already have NET_SKB_PAD bytes of headroom, so we don't need to add any extra space here. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0e501714d47..b534a1be540 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1896,8 +1896,6 @@ static inline int __skb_cow(struct sk_buff *skb, unsigned int headroom,
{
int delta = 0;
- if (headroom < NET_SKB_PAD)
- headroom = NET_SKB_PAD;
if (headroom > skb_headroom(skb))
delta = headroom - skb_headroom(skb);