linux-kernel - Re: [PATCH v2] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc

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Date:   Tue, 12 Jul 2022 14:39:58 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     ubizjak@...il.com, linux-kernel@...r.kernel.org,
        linux-block@...r.kernel.org
Subject: Re: [PATCH v2] block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below

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