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gro: Only use skb_gro_header for completely non-linear packets

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Currently skb_gro_header is used for packets which put the hardware
header in skb->data with the rest in frags.  Since the drivers that
need this optimisation all provide completely non-linear packets,
we can gain extra optimisations by only performing the frag0
optimisation for completely non-linear packets.

In particular, we can simply test frag0 (instead of skb_headlen)
to see whether the optimisation is in force.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2009-05-26 18:50:23 +00:00 committed by David S. Miller
parent 67147ba99a
commit 78d3fd0b7d
2 changed files with 8 additions and 6 deletions
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11
include/linux/netdevice.h
View File

@ -1135,22 +1135,23 @@ static inline void *skb_gro_header(struct sk_buff *skb, unsigned int hlen)
hlen += offset;
if (!NAPI_GRO_CB(skb)->frag0 ||
unlikely(skb_shinfo(skb)->frags[0].size + skb_headlen(skb) < hlen))
unlikely(skb_shinfo(skb)->frags[0].size < hlen)) {
NAPI_GRO_CB(skb)->frag0 = NULL;
return pskb_may_pull(skb, hlen) ? skb->data + offset : NULL;
}
return NAPI_GRO_CB(skb)->frag0 + offset;
}
static inline void *skb_gro_mac_header(struct sk_buff *skb)
{
return skb_headlen(skb) ? skb_mac_header(skb) :
NAPI_GRO_CB(skb)->frag0;
return NAPI_GRO_CB(skb)->frag0 ?: skb_mac_header(skb);
}
static inline void *skb_gro_network_header(struct sk_buff *skb)
{
return skb_headlen(skb) ? skb_network_header(skb) :
NAPI_GRO_CB(skb)->frag0 + skb_network_offset(skb);
return (NAPI_GRO_CB(skb)->frag0 ?: skb->data) +
skb_network_offset(skb);
}
static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev,

3
net/core/dev.c
View File

@ -2510,7 +2510,8 @@ void skb_gro_reset_offset(struct sk_buff *skb)
NAPI_GRO_CB(skb)->data_offset = 0;
NAPI_GRO_CB(skb)->frag0 = NULL;
if (!skb_headlen(skb) && !PageHighMem(skb_shinfo(skb)->frags[0].page))
if (skb->mac_header == skb->tail &&
!PageHighMem(skb_shinfo(skb)->frags[0].page))
NAPI_GRO_CB(skb)->frag0 =
page_address(skb_shinfo(skb)->frags[0].page) +
skb_shinfo(skb)->frags[0].page_offset;