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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-07-22 19:09:08 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-07-24 21:05:57 -0700 |
| commit | fed66381d65a35198639f564365e61a7f256bf79 (patch) | |
| tree | e4d4c83f135f58c32a85454e28e33407711f7718 | |
| parent | c1f79426e2df5ef96fe3e76de6c7606d15bf390b (diff) | |
| download | linux-3.10-fed66381d65a35198639f564365e61a7f256bf79.tar.gz linux-3.10-fed66381d65a35198639f564365e61a7f256bf79.tar.bz2 linux-3.10-fed66381d65a35198639f564365e61a7f256bf79.zip | |
net: pskb_expand_head() optimization
Move frags[] at the end of struct skb_shared_info, and make
pskb_expand_head() copy only the used part of it instead of whole array.
This should avoid kmemcheck warnings and speedup pskb_expand_head() as
well, avoiding a lot of cache misses.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/skbuff.h | 3 | ||||
| -rw-r--r-- | net/core/skbuff.c | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f5aa87e1e0c..d89876b806a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -202,10 +202,11 @@ struct skb_shared_info { */ atomic_t dataref; - skb_frag_t frags[MAX_SKB_FRAGS]; /* Intermediate layers must ensure that destructor_arg * remains valid until skb destructor */ void * destructor_arg; + /* must be last field, see pskb_expand_head() */ + skb_frag_t frags[MAX_SKB_FRAGS]; }; /* We divide dataref into two halves. The higher 16 bits hold references diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 76d33ca5f03..7da58a25ad9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -817,7 +817,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, memcpy(data + nhead, skb->head, skb->tail - skb->head); #endif memcpy(data + size, skb_end_pointer(skb), - sizeof(struct skb_shared_info)); + offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags])); for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) get_page(skb_shinfo(skb)->frags[i].page); |