Re: [PATCH v2] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below

From: Jens Axboe
Date: Tue Jul 12 2022 - 16:40:20 EST


On Tue, 12 Jul 2022 17:05:47 +0200, Uros Bizjak wrote:
> Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in
> atomic_inc_below. x86 CMPXCHG instruction returns success in ZF flag,
> so this change saves a compare after cmpxchg (and related move instruction
> in front of cmpxchg).
>
> Also, atomic_try_cmpxchg implicitly assigns old *ptr value to "old" when
> cmpxchg fails, enabling further code simplifications.
>
> [...]

Applied, thanks!

[1/1] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below
commit: f4b1e27db49c8b985b116aa99481b4c6a4342ed4

Best regards,
--
Jens Axboe