Re: [PATCH net-next v2 3/3] udp: try to avoid 2 cache miss on dequeue

On Tue, 2017-06-06 at 16:23 +0200, Paolo Abeni wrote:

when udp_recvmsg() is executed, on x86_64 and other archs, most skb
fields are on cold cachelines.
If the skb are linear and the kernel don't need to compute the udp
csum, only a handful of skb fields are required by udp_recvmsg().
Since we already use skb->dev_scratch to cache hot data, and
there are 32 bits unused on 64 bit archs, use such field to cache
as much data as we can, and try to prefetch on dequeue the relevant
fields that are left out.

Acked-by: Eric Dumazet <redacted>