Re: [PATCH net-next v3 3/4] net: use skb->priority for overloading skb->dropcount and skb->reserved_tailroom instead of skb->mark

On Mon, 2015-02-23 at 21:25 +0200, Eyal Birger wrote:

The original commit introducing dropcount for af_packet
(see http://marc.info/?l=linux-netdev&m=125450261121971) also claimed
the proper location would in fact be skb->cb[]. However, it was also
claimed that
skb->cb[] is all used up.

Things are even more complicated now as dropcount became a socket
level feature and skb->cb[] is handled differently in each protocol family.

I did a check, and all current sock_recv_ts_and_drops() users have room
in skb->cb[] to store dropcount, say at the beginning of the array.

I have no big opinion here, but intuitively dropcount has a very short
lifetime and skb->cb[] seems appropriate.