[PATCH] cgroup: make cgroups info more readable

[PATCH] cgroup: make cgroups info more readable

[Huan Yang]

The current cgroups output format is based on tabs, which
may cause misalignment of output information.

Using placeholder formatting can make the output information
more readable.

Signed-off-by: Huan Yang <link@vivo.com>
---
 kernel/cgroup/cgroup-v1.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 520a11cb12f4..c082a78f4c22 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -669,15 +669,16 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
 	struct cgroup_subsys *ss;
 	int i;
 
-	seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
+	seq_printf(m, "%16s %16s %16s %16s\n", "#subsys_name", "hierarchy",
+		   "num_cgroups", "enabled");
 	/*
 	 * Grab the subsystems state racily. No need to add avenue to
 	 * cgroup_mutex contention.
 	 */
 
 	for_each_subsys(ss, i)
-		seq_printf(m, "%s\t%d\t%d\t%d\n",
-			   ss->legacy_name, ss->root->hierarchy_id,
+		seq_printf(m, "%16s %16d %16d %16d\n", ss->legacy_name,
+			   ss->root->hierarchy_id,
 			   atomic_read(&ss->root->nr_cgrps),
 			   cgroup_ssid_enabled(i));
 
-- 
2.34.1

Re: [PATCH] cgroup: make cgroups info more readable

[xiujianfeng]

Hi,

I found a discussion about this change in the email thread bellow, and
hope it helps you.

https://lore.kernel.org/all/YwMwlMv%2FtK3sRXbB@slm.duckdns.org/#t

On 2024/4/9 10:18, Huan Yang wrote:
> The current cgroups output format is based on tabs, which
> may cause misalignment of output information.
> 
> Using placeholder formatting can make the output information
> more readable.
> 
> Signed-off-by: Huan Yang <link@vivo.com>
> ---
>  kernel/cgroup/cgroup-v1.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
> index 520a11cb12f4..c082a78f4c22 100644
> --- a/kernel/cgroup/cgroup-v1.c
> +++ b/kernel/cgroup/cgroup-v1.c
> @@ -669,15 +669,16 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
>  	struct cgroup_subsys *ss;
>  	int i;
>  
> -	seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
> +	seq_printf(m, "%16s %16s %16s %16s\n", "#subsys_name", "hierarchy",
> +		   "num_cgroups", "enabled");
>  	/*
>  	 * Grab the subsystems state racily. No need to add avenue to
>  	 * cgroup_mutex contention.
>  	 */
>  
>  	for_each_subsys(ss, i)
> -		seq_printf(m, "%s\t%d\t%d\t%d\n",
> -			   ss->legacy_name, ss->root->hierarchy_id,
> +		seq_printf(m, "%16s %16d %16d %16d\n", ss->legacy_name,
> +			   ss->root->hierarchy_id,
>  			   atomic_read(&ss->root->nr_cgrps),
>  			   cgroup_ssid_enabled(i));
>  

Re: [PATCH] cgroup: make cgroups info more readable

[Huan Yang]

HI jianfeng

在 2024/4/19 11:33, xiujianfeng 写道:
> [Some people who received this message don't often get email from xiujianfeng@huawei.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>
> Hi,
>
> I found a discussion about this change in the email thread bellow, and
> hope it helps you.
It's helpful to know why this patch not need, thank you.
>
> https://lore.kernel.org/all/YwMwlMv%2FtK3sRXbB@slm.duckdns.org/#t

I have a question, that, now that only for cgroup1, when I running qemu 
ubuntu, I got this:

 > mount | grep cgroup
 > cgroup2 on /sys/fs/cgroup type cgroup2 
(rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot)

Only cgroup2 mount in my system, but /proc/cgroup also worked, maybe 
better to disable this when only cgroup2 mounted?

> On 2024/4/9 10:18, Huan Yang wrote:
>> The current cgroups output format is based on tabs, which
>> may cause misalignment of output information.
>>
>> Using placeholder formatting can make the output information
>> more readable.
>>
>> Signed-off-by: Huan Yang <link@vivo.com>
>> ---
>>   kernel/cgroup/cgroup-v1.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
>> index 520a11cb12f4..c082a78f4c22 100644
>> --- a/kernel/cgroup/cgroup-v1.c
>> +++ b/kernel/cgroup/cgroup-v1.c
>> @@ -669,15 +669,16 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
>>        struct cgroup_subsys *ss;
>>        int i;
>>
>> -     seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
>> +     seq_printf(m, "%16s %16s %16s %16s\n", "#subsys_name", "hierarchy",
>> +                "num_cgroups", "enabled");
>>        /*
>>         * Grab the subsystems state racily. No need to add avenue to
>>         * cgroup_mutex contention.
>>         */
>>
>>        for_each_subsys(ss, i)
>> -             seq_printf(m, "%s\t%d\t%d\t%d\n",
>> -                        ss->legacy_name, ss->root->hierarchy_id,
>> +             seq_printf(m, "%16s %16d %16d %16d\n", ss->legacy_name,
>> +                        ss->root->hierarchy_id,
>>                           atomic_read(&ss->root->nr_cgrps),
>>                           cgroup_ssid_enabled(i));
>>

Re: [PATCH] cgroup: make cgroups info more readable

[xiujianfeng]

Hi,

On 2024/4/19 14:25, Huan Yang wrote:
> HI jianfeng
> 
> 在 2024/4/19 11:33, xiujianfeng 写道:
>> [Some people who received this message don't often get email from
>> xiujianfeng@huawei.com. Learn why this is important at
>> https://aka.ms/LearnAboutSenderIdentification ]
>>
>> Hi,
>>
>> I found a discussion about this change in the email thread bellow, and
>> hope it helps you.
> It's helpful to know why this patch not need, thank you.
>>
>> https://lore.kernel.org/all/YwMwlMv%2FtK3sRXbB@slm.duckdns.org/#t
> 
> I have a question, that, now that only for cgroup1, when I running qemu
> ubuntu, I got this:
> 
>> mount | grep cgroup
>> cgroup2 on /sys/fs/cgroup type cgroup2
> (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot)
> 
> Only cgroup2 mount in my system, but /proc/cgroup also worked, maybe
> better to disable this when only cgroup2 mounted?

I’m not the maintainer, so the official answer to this question should
be left to them:).

However, I don’t think this is the right way. Even though the
information shown by /proc/cgroups doesn’t seem as useful for cgroup2 as
for cgroup1 due to cgroup2 has only single hierarchy, it’s not entirely
useless, IMHO.

> 
>> On 2024/4/9 10:18, Huan Yang wrote:
>>> The current cgroups output format is based on tabs, which
>>> may cause misalignment of output information.
>>>
>>> Using placeholder formatting can make the output information
>>> more readable.
>>>
>>> Signed-off-by: Huan Yang <link@vivo.com>
>>> ---
>>>   kernel/cgroup/cgroup-v1.c | 7 ++++---
>>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
>>> index 520a11cb12f4..c082a78f4c22 100644
>>> --- a/kernel/cgroup/cgroup-v1.c
>>> +++ b/kernel/cgroup/cgroup-v1.c
>>> @@ -669,15 +669,16 @@ int proc_cgroupstats_show(struct seq_file *m,
>>> void *v)
>>>        struct cgroup_subsys *ss;
>>>        int i;
>>>
>>> -     seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n");
>>> +     seq_printf(m, "%16s %16s %16s %16s\n", "#subsys_name",
>>> "hierarchy",
>>> +                "num_cgroups", "enabled");
>>>        /*
>>>         * Grab the subsystems state racily. No need to add avenue to
>>>         * cgroup_mutex contention.
>>>         */
>>>
>>>        for_each_subsys(ss, i)
>>> -             seq_printf(m, "%s\t%d\t%d\t%d\n",
>>> -                        ss->legacy_name, ss->root->hierarchy_id,
>>> +             seq_printf(m, "%16s %16d %16d %16d\n", ss->legacy_name,
>>> +                        ss->root->hierarchy_id,
>>>                           atomic_read(&ss->root->nr_cgrps),
>>>                           cgroup_ssid_enabled(i));
>>>

Re: [PATCH] cgroup: make cgroups info more readable

[Huan Yang]

在 2024/4/20 10:47, xiujianfeng 写道:
> However, I don’t think this is the right way. Even though the
> information shown by /proc/cgroups doesn’t seem as useful for cgroup2 as
> for cgroup1 due to cgroup2 has only single hierarchy, it’s not entirely
OK, thanks for your reply
> useless, IMHO.