diff options
| author | Felix Fietkau <nbd@openwrt.org> | 2012-05-29 03:35:08 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-05-29 17:30:08 -0400 |
| commit | 617c8c11236716dcbda877e764b7bf37c6fd8063 (patch) | |
| tree | 78211c03e4e80eb1ea448c45139ce07534ccd238 | |
| parent | 79fba9f51755c704c0a7d7b7f0df10874dc0a744 (diff) | |
| download | linux-617c8c11236716dcbda877e764b7bf37c6fd8063.tar.bz2 | |
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>
| -rw-r--r-- | include/linux/skbuff.h | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0e501714d47f..b534a1be540a 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); |