blk-iolatency: Use atomic{,64}_try_cmpxchg
Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in check_scale_change and atomic64_try_cmpxchg in blkcg_iolatency_done_bio. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). No functional change intended. Signed-off-by:Uros Bizjak <ubizjak@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20220712151947.6783-1-ubizjak@gmail.com Signed-off-by:
Jens Axboe <axboe@kernel.dk>
parent
939f9dd0
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