sched/balancing: Rename find_idlest_group() => sched_balance_find_dst_group()

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@kernel.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20240308111819.1101550-13-mingo@kernel.org

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 02ff0272b2e49bacfe022e1fc9e32f9c1fcc3c46..d0c3a091d7d1dcee048656c5087b2f1a23dac4bf 100644 (file)
--- 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;