Re: [PATCH v2] blk-cgroup: Use atomic{,64}_try_cmpxchg

From: Jens Axboe
Date: Tue Jul 12 2022 - 17:46:13 EST

On Tue, 12 Jul 2022 17:44:55 +0200, Uros Bizjak wrote:
> Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old
> in blkcg_unuse_delay, blkcg_set_delay and blkcg_clear_delay and
> atomic64_try_cmpxchg in blkcg_scale_delay. 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] blk-cgroup: Use atomic{,64}_try_cmpxchg
commit: 96388f57d2aad9836b2c589181fa1dbaba4066b4

Best regards,
Jens Axboe