sched/clock: Use try_cmpxchg64 in sched_clock_{local,remote}
authorUros Bizjak <ubizjak@gmail.com>
Wed, 18 May 2022 18:49:53 +0000 (20:49 +0200)
committerPeter Zijlstra <peterz@infradead.org>
Thu, 19 May 2022 21:46:09 +0000 (23:46 +0200)
commit8491d1bdf5de152f27fc941e2dcdc4e66c950542
treec971126e067abf917f5204a5cd2ce87305240cae
parentc2df0a6af177b6c06a859806a876f92b072dc624
sched/clock: Use try_cmpxchg64 in sched_clock_{local,remote}

Use try_cmpxchg64 instead of cmpxchg64 (*ptr, old, new) != old in
sched_clock_{local,remote}. x86 cmpxchg returns success in ZF flag,
so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220518184953.3446778-1-ubizjak@gmail.com
kernel/sched/clock.c