sched/fair: use try_cmpxchg in task_numa_work
authorUros Bizjak <ubizjak@gmail.com>
Mon, 22 Aug 2022 17:39:56 +0000 (19:39 +0200)
committerAndrew Morton <akpm@linux-foundation.org>
Fri, 18 Nov 2022 21:55:09 +0000 (13:55 -0800)
commit8baceabca656d5ef4494cdeb3b9b9fbb844ac613
treeb60ac4475d4ad3d2b3ddf83a6d0adb199ca48a2e
parent333d073dee3a6865171d43e3b0a9ff688bff5891
sched/fair: use try_cmpxchg in task_numa_work

Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
task_numa_work.  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.

Link: https://lkml.kernel.org/r/20220822173956.82525-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kernel/sched/fair.c