From: Paolo Abeni <pab...@redhat.com>
Date: Fri, 25 May 2018 16:28:44 +0200
> The struct Qdisc has a lot of holes, especially after commit
> a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback"),
> which as a side effect, moved the fields just after 'busylock'
> on a new cacheline.
>
> Since both 'padded' and 'refcnt' are not updated frequently, and
> there is a hole before 'gso_skb', we can move such fields there,
> saving a cacheline without any performance side effect.
>
> Before this commit:
>
> pahole -C Qdisc net/sche/sch_generic.o
> # ...
> /* size: 384, cachelines: 6, members: 25 */
> /* sum members: 236, holes: 3, sum holes: 92 */
> /* padding: 56 */
>
> After this commit:
> pahole -C Qdisc net/sche/sch_generic.o
> # ...
> /* size: 320, cachelines: 5, members: 25 */
> /* sum members: 236, holes: 2, sum holes: 28 */
> /* padding: 56 */
>
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
Applied.
