[PATCH] sched/fair: Fix misuse of available_idle_cpu()

From: Abel Wu
Date: Thu Sep 08 2022 - 04:07:28 EST

The function available_idle_cpu() was introduced to distinguish
between the code paths that cares if the vCPU is preempted and
the ones don't care. In general, available_idle_cpu() is used in
selecting cpus for immediate use, e.g. ttwu. While idle_cpu() is
used in the paths that only cares about the cpu is idle or not,
and __update_idle_core() is one of them.

Use idle_cpu() instead in the idle path to make has_idle_core
a better hint.

Fixes: 943d355d7fee (sched/core: Distinguish between idle_cpu() calls based on desired effect, introduce available_idle_cpu())
Signed-off-by: Abel Wu <wuyun.abel@xxxxxxxxxxxxx>
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 efceb670e755..5a76d814f8bc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6302,7 +6302,7 @@ void __update_idle_core(struct rq *rq)
if (cpu == core)

- if (!available_idle_cpu(cpu))
+ if (!idle_cpu(cpu))
goto unlock;