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.

Signed-off-by: Vitalii Bursov <vitaly@bursov.com>
---
 kernel/sched/debug.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 8d5d98a5834d..c1eb9a1afd13 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -425,6 +425,7 @@ 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)
-- 
2.20.1

On 03/04/24 16:28, Vitalii Bursov wrote:
> 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.
>
> Signed-off-by: Vitalii Bursov <vitaly@bursov.com>
> ---
>  kernel/sched/debug.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 8d5d98a5834d..c1eb9a1afd13 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -425,6 +425,7 @@ 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);

How about reusing the SDM macro? ->flags and ->groups_flags get special
treatment for pretty printing, but the others don't need that.
---
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index c1eb9a1afd13e..f97902208b34d 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -419,13 +419,13 @@ static void register_sd(struct sched_domain *sd, struct dentry *parent)
 	SDM(u32,   0644, busy_factor);
 	SDM(u32,   0644, imbalance_pct);
 	SDM(u32,   0644, cache_nice_tries);
+	SDM(u32,   0444, level);
 	SDM(str,   0444, name);
 
 #undef SDM
 
 	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)

On 04.04.24 17:21, Valentin Schneider wrote:
> On 03/04/24 16:28, Vitalii Bursov wrote:
>> 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.
>>
>> Signed-off-by: Vitalii Bursov <vitaly@bursov.com>
>> ---
>>  kernel/sched/debug.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
>> index 8d5d98a5834d..c1eb9a1afd13 100644
>> --- a/kernel/sched/debug.c
>> +++ b/kernel/sched/debug.c
>> @@ -425,6 +425,7 @@ 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);
> 
> How about reusing the SDM macro? ->flags and ->groups_flags get special
> treatment for pretty printing, but the others don't need that.
> ---
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index c1eb9a1afd13e..f97902208b34d 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -419,13 +419,13 @@ static void register_sd(struct sched_domain *sd, struct dentry *parent)
>  	SDM(u32,   0644, busy_factor);
>  	SDM(u32,   0644, imbalance_pct);
>  	SDM(u32,   0644, cache_nice_tries);
> +	SDM(u32,   0444, level);
>  	SDM(str,   0444, name);
>  
>  #undef SDM
>  
>  	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)
> 

This worked when I tried it. The reason why I chose an explicit implementation
with debugfs_create_u32() is because "level" is "int" and there's no
debugfs_create_{s32,int}(). While casting is not the best option either, it
hints that types mismatch.

In a few other cases when types do not match, casting is usually used. e.g.
mod_debug_add_ulong macro in kernel/module/stats.c:
#define mod_debug_add_ulong(name) debugfs_create_ulong(#name, 0400, mod_debugfs_root, (unsigned long *) &name.counter)
where "counter" can be s64 from the atomic64.

Thanks

On Wed, 3 Apr 2024 at 15:28, Vitalii Bursov <vitaly@bursov.com> wrote:
>
> 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.
>
> Signed-off-by: Vitalii Bursov <vitaly@bursov.com>

Acked-by: Vincent Guittot <vincent.guittot@linaro.org>

> ---
>  kernel/sched/debug.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 8d5d98a5834d..c1eb9a1afd13 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -425,6 +425,7 @@ 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)
> --
> 2.20.1
>