[PATCH v2 2/3] sched/fair: Use rq in idle_cpu_without()

From: Pierre Gondois
Date: Mon Jan 15 2024 - 09:35:12 EST


idle_cpu_without() could receive a 'struct rq' instead of a
CPU number to avoid converting the CPU number to a 'struct rq'
two times. Indeed update_sg_wakeup_stats() already makes the
conversion.
idle_cpu_without() is also renamed to idle_rq_without()
to match the input parameter.

Reviewed-by: Shrikanth Hegde <sshegde@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
---
kernel/sched/fair.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d7a3c63a2171..97d9e0d32337 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10105,23 +10105,21 @@ static unsigned int task_running_on_cpu(int cpu, struct task_struct *p)
}

/**
- * idle_cpu_without - would a given CPU be idle without p ?
- * @cpu: the processor on which idleness is tested.
+ * idle_rq_without - would a given rq be idle without p ?
+ * @rq: the rq on which idleness is tested.
* @p: task which should be ignored.
*
- * Return: 1 if the CPU would be idle. 0 otherwise.
+ * Return: 1 if the rq would be idle. 0 otherwise.
*/
-static int idle_cpu_without(int cpu, struct task_struct *p)
+static int idle_rq_without(struct rq *rq, struct task_struct *p)
{
- struct rq *rq = cpu_rq(cpu);
-
if (rq->curr != rq->idle && rq->curr != p)
return 0;

/*
* rq->nr_running can't be used but an updated version without the
* impact of p on cpu must be used instead. The updated nr_running
- * be computed and tested before calling idle_cpu_without().
+ * be computed and tested before calling idle_rq_without().
*/

#ifdef CONFIG_SMP
@@ -10166,9 +10164,9 @@ static inline void update_sg_wakeup_stats(struct sched_domain *sd,
sgs->sum_nr_running += nr_running;

/*
- * No need to call idle_cpu_without() if nr_running is not 0
+ * No need to call idle_rq_without() if nr_running is not 0
*/
- if (!nr_running && idle_cpu_without(i, p))
+ if (!nr_running && idle_rq_without(rq, p))
sgs->idle_cpus++;

/* Check if task fits in the CPU */
--
2.25.1