sched/debug: Dump domains' level

JIRA: https://issues.redhat.com/browse/RHEL-48226

commit 287372f
Author: Vitalii Bursov <vitaly@bursov.com>
Date:   Tue Apr 30 18:05:24 2024 +0300

    sched/debug: Dump domains' level

    Knowing domain's level exactly can be useful when setting
    relax_domain_level or cpuset.sched_relax_domain_level

    Usage:

      cat /debug/sched/domains/cpu0/domain1/level

    to dump cpu0 domain1's level.

    SDM macro is not used because sd->level is 'int' and
    it would hide the type mismatch between 'int' and 'u32'.

    Signed-off-by: Vitalii Bursov <vitaly@bursov.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
    Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
    Reviewed-by: Valentin Schneider <vschneid@redhat.com>
    Link: https://lore.kernel.org/r/9489b6475f6dd6fbc67c617752d4216fa094da53.1714488502.git.vitaly@bursov.com

Signed-off-by: Phil Auld <pauld@redhat.com>

Author: auldp

kernel/sched/debug.c

@@ -428,6 +428,7 @@ static void register_sd(struct sched_domain *sd, struct dentry *parent)
 
 	debugfs_create_file("flags", 0444, parent, &sd->flags, &sd_flags_fops);
 	debugfs_create_file("groups_flags", 0444, parent, &sd->groups->flags, &sd_flags_fops);
+	debugfs_create_u32("level", 0444, parent, (u32 *)&sd->level);
 }
 
 void update_sched_domain_debugfs(void)