Re: [net-next 01/11] ixgbe: Support using build_skb in the case that jumbo frames are disabled

On Fri, 2013-04-12 at 06:10 -0700, Eric Dumazet wrote:

Strange. I feel you overestimate the final skb->truesize

The name 'truesize' is a bit misleading here, as its the size of
skb->head. A better name would have been frag_size, and you should not
include in it the struct skb_shared_info overhead because build_skb()
does it :

Oh well, build_skb() does :

size -= SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 

so your patch is fine, only the @truesize name is misleading.

skb->truesize will be set to SKB_TRUESIZE(frag_size)

#define SKB_TRUESIZE(X) ((X) +                                          \
                         SKB_DATA_ALIGN(sizeof(struct sk_buff)) +       \
                         SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))