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| author | Felix Fietkau <nbd@openwrt.org> | 2012-05-29 03:35:08 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-10 00:36:15 +0900 |
| commit | 010589e2bce841733dc989fd56c5c3aba41a759c (patch) | |
| tree | bd4a2be410ad1c7ff51ffad8d80e4d65c7ab1c8d /include | |
| parent | ea1ae37f4a2c41ea684f2e725332147eb6496026 (diff) | |
| download | linux-stable-010589e2bce841733dc989fd56c5c3aba41a759c.tar.gz linux-stable-010589e2bce841733dc989fd56c5c3aba41a759c.tar.bz2 linux-stable-010589e2bce841733dc989fd56c5c3aba41a759c.zip | |
skb: avoid unnecessary reallocations in __skb_cow
[ Upstream commit 617c8c11236716dcbda877e764b7bf37c6fd8063 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -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 111f26b6e28b..c1689071fa2f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1881,8 +1881,6 @@ 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); |