Re: [PATCH] is_core_idle() is using a wrong variable

From: Peter Zijlstra
Date: Wed Jul 28 2021 - 06:43:02 EST


On Thu, Jul 22, 2021 at 09:39:46AM +0300, mika.penttila@xxxxxxxxx wrote:
> From: Mika Penttilä <mika.penttila@xxxxxxxxx>
>
> is_core_idle() was using a wrong variable in the loop test. Fix it.
>
> Signed-off-by: Mika Penttilä <mika.penttila@xxxxxxxxx>

Thanks!

---
Subject: sched/numa: Fix is_core_idle()
From: Mika Penttilä <mika.penttila@xxxxxxxxx>
Date: Thu, 22 Jul 2021 09:39:46 +0300

From: Mika Penttilä <mika.penttila@xxxxxxxxx>

Use the loop variable instead of the function argument to test the
other SMT siblings for idle.

Fixes: ff7db0bf24db ("sched/numa: Prefer using an idle CPU as a migration target instead of comparing tasks")
Signed-off-by: Mika Penttilä <mika.penttila@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210722063946.28951-1-mika.penttila@xxxxxxxxx
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1486,7 +1486,7 @@ static inline bool is_core_idle(int cpu)
if (cpu == sibling)
continue;

- if (!idle_cpu(cpu))
+ if (!idle_cpu(sibling))
return false;
}
#endif