[PATCH 12/13] sched/balancing: Rename find_idlest_group() => sched_balance_find_dst_group()

From: Ingo Molnar
Date: Fri Mar 08 2024 - 06:21:28 EST


Standardize scheduler load-balancing function names on the
sched_balance_() prefix.

Also use 'dst' instead of 'idlest', because it's not really
true that we return the 'idlest' group or CPU, we sort by
idle-exit latency and only return the idlest CPUs from the
lowest-latency set of CPUs.

The true 'idlest' CPUs often remain idle for a long time
and are never returned as long as the system is under-loaded.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Shrikanth Hegde <sshegde@xxxxxxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
---
kernel/sched/fair.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 02ff0272b2e4..d0c3a091d7d1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7098,7 +7098,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
}

static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);

/*
* sched_balance_find_dst_group_cpu - find the idlest CPU among the CPUs in the group.
@@ -7185,7 +7185,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
continue;
}

- group = find_idlest_group(sd, p, cpu);
+ group = sched_balance_find_dst_group(sd, p, cpu);
if (!group) {
sd = sd->child;
continue;
@@ -10296,13 +10296,13 @@ static bool update_pick_idlest(struct sched_group *idlest,
}

/*
- * find_idlest_group() finds and returns the least busy CPU group within the
+ * sched_balance_find_dst_group() finds and returns the least busy CPU group within the
* domain.
*
* Assumes p is allowed on at least one CPU in sd.
*/
static struct sched_group *
-find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
+sched_balance_find_dst_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
{
struct sched_group *idlest = NULL, *local = NULL, *group = sd->groups;
struct sg_lb_stats local_sgs, tmp_sgs;
--
2.40.1