sched/balancing: Rename find_idlest_group_cpu() => sched_balance_find_dst_group_cpu()

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

Also use 'dst' instead of 'idlest': while historically correct,
today it's not really true anymore 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/20240308111819.1101550-12-mingo@kernel.org

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index aa5ff0efcca84bcdc9b48ec37567050d806f4f33..02ff0272b2e49bacfe022e1fc9e32f9c1fcc3c46 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7101,10 +7101,10 @@ static struct sched_group *
 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu);
 
 /*
- * find_idlest_group_cpu - find the idlest CPU among the CPUs in the group.
+ * sched_balance_find_dst_group_cpu - find the idlest CPU among the CPUs in the group.
  */
 static int
-find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
+sched_balance_find_dst_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
 {
        unsigned long load, min_load = ULONG_MAX;
        unsigned int min_exit_latency = UINT_MAX;
@@ -7191,7 +7191,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p
                        continue;
                }
 
-               new_cpu = find_idlest_group_cpu(group, p, cpu);
+               new_cpu = sched_balance_find_dst_group_cpu(group, p, cpu);
                if (new_cpu == cpu) {
                        /* Now try balancing at a lower domain level of 'cpu': */
                        sd = sd->child;