Commit Graph

4 Commits

Author SHA1 Message Date
Eric Dumazet
042a53a9e4 net: skb_shared_info optimization
skb_dma_unmap() is quite expensive for small packets,
because we use two different cache lines from skb_shared_info.

One to access nr_frags, one to access dma_maps[0]

Instead of dma_maps being an array of MAX_SKB_FRAGS + 1 elements,
let dma_head alone in a new dma_head field, close to nr_frags,
to reduce cache lines misses.

Tested on my dev machine (bnx2 & tg3 adapters), nice speedup !

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-08 00:21:48 -07:00
Eric Dumazet
eae3f29cc7 net: num_dma_maps is not used
Get rid of num_dma_maps in struct skb_shared_info, as it seems unused.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-06-08 00:20:23 -07:00
Dimitris Michailidis
ab396eb03f net: Fix off-by-one in skb_dma_map
The unwind loop iterates down to -1 instead of stopping at 0 and ends up
accessing ->frags[-1].

Signed-off-by: Dimitris Michailidis <dm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-12 21:07:34 -07:00
David S. Miller
a40c24a133 net: Add SKB DMA mapping helper functions.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-11 04:51:14 -07:00