From: Eric Dumazet <eduma...@google.com>
Date: Mon, 6 Jun 2016 09:37:14 -0700
> A while back, I sent one RFC patch using lockless stats gathering
> on 64bit arches.
>
> This patch series does it more cleanly, using a seqcount.
>
> Since qdisc/class stats are written at dequeue() time,
> we can ask the dequeue to change the seqcount, so that
> stats readers can avoid taking the root qdisc lock,
> and instead the typical read_seqcount_{begin|retry} guarded
> loop.
>
> This does not change fast path costs, as the seqcount
> increments are not more expensive than the bit manipulation,
> and allows readers to not freeze the fast path anymore.
I like this, looks great!
Applied.
