Re: reasons for dev_alloc_skb +16?

[Andi Kleen <ak@xxxxxxx>]

On Wed, 9 Jul 2003 11:25:53 -0400
Jeff Garzik <jgarzik@xxxxxxxxx> wrote:

> I knew this at one time, but have forgotten it :)
> 
> What is the reason for adding 16 to the dev_alloc_skb length?
> (and skb_reserve of the same length)

For the skb_reserve alignment to align the IP header. 

But it's not clear it is still a good idea because it leads to cache line 
misalignment of the beginning of the packet, forcing the card to do a
costly Read-Modify-Write cycle.

-Andi