Messages in this thread Patch in this message | | | From | Uros Bizjak <> | Subject | [PATCH] sched/fair: Use try_cmpxchg in task_numa_work | Date | Mon, 22 Aug 2022 19:39:56 +0200 |
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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.
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: Uros Bizjak <ubizjak@gmail.com> --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 914096c5b1ae..efe73ee89989 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2802,7 +2802,7 @@ static void task_numa_work(struct callback_head *work) } next_scan = now + msecs_to_jiffies(p->numa_scan_period); - if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate) + if (!try_cmpxchg(&mm->numa_next_scan, &migrate, next_scan)) return; /* -- 2.37.1
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