| commit | 617c8c11236716dcbda877e764b7bf37c6fd8063 | |
| author | Felix Fietkau <nbd@openwrt.org> | |
| Tue, 29 May 2012 03:35:08 +0000 (29 03:35 +0000) | ||
| committer | David S. Miller <davem@davemloft.net> | |
| Tue, 29 May 2012 21:30:08 +0000 (29 17:30 -0400) | ||
| tree | 78211c03e4e80eb1ea448c45139ce07534ccd238 | treesnapshot (tar.gz zip) |
| parent | 79fba9f51755c704c0a7d7b7f0df10874dc0a744 | commitdiff |
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>
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>
| include/linux/skbuff.h | diffblobblamehistory |