2021-11-15 01:13:39

by Wei Yang

Subject: [Patch v2] cgroup: pretty format /proc/cgroups

Current /proc/cgroups looks like this:

subsys_name hierarchy num_cgroups enabled
cpuset 3 1 1
cpu 2 1 1
cpuacct 2 1 1
memory 4 71 1
freezer 5 1 1

Let's align the title and value. After this patch, it looks like this.

subsys_name hierarchy num_cgroups enabled
cpuset 5 1 1
cpu 3 1 1
cpuacct 3 1 1
memory 2 71 1
freezer 4 1 1

Signed-off-by: Wei Yang <[email protected]>

---
v2: the title line is omitted for the start "#"

---
kernel/cgroup/cgroup-v1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 81c9e0685948..5b177e0eca2c 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -664,7 +664,7 @@ int proc_cgroupstats_show(struct seq_file *m, void *v)
*/

for_each_subsys(ss, i)
- seq_printf(m, "%s\t%d\t%d\t%d\n",
+ seq_printf(m, "%12s\t%9d\t%11d\t%7d\n",
ss->legacy_name, ss->root->hierarchy_id,
atomic_read(&ss->root->nr_cgrps),
cgroup_ssid_enabled(i));
--
2.33.1

2021-11-16 00:11:14

by Tejun Heo

Subject: Re: [Patch v2] cgroup: pretty format /proc/cgroups

On Mon, Nov 15, 2021 at 01:12:53AM +0000, Wei Yang wrote:
> Current /proc/cgroups looks like this:
>
> subsys_name hierarchy num_cgroups enabled
> cpuset 3 1 1
> cpu 2 1 1
> cpuacct 2 1 1
> memory 4 71 1
> freezer 5 1 1
>
> Let's align the title and value. After this patch, it looks like this.
>
> subsys_name hierarchy num_cgroups enabled
> cpuset 5 1 1
> cpu 3 1 1
> cpuacct 3 1 1
> memory 2 71 1
> freezer 4 1 1
>
> Signed-off-by: Wei Yang <[email protected]>

So, I know it's silly but the file is dumb \t formatted (ie. single \t
between fields) and am slightly worried that changing the format might break
some dumb userspace tooling. Given that the information isn't really needed
for cgroup2 anyway, it prolly is better to leave it as-is, I think.

Thanks.

--
tejun

2021-11-16 18:00:27

by Michal Koutný

Subject: Re: [Patch v2] cgroup: pretty format /proc/cgroups

Hello.

On Mon, Nov 15, 2021 at 01:12:53AM +0000, Wei Yang <[email protected]> wrote:
> Let's align the title and value. After this patch, it looks like this.

For machines this change may come as a surprise (so better not change
it).

For humans (for instance column from util-linux)

$ column -t /proc/cgroups
#subsys_name hierarchy num_cgroups enabled
cpuset 11 2 1
cpu 4 9 1
cpuacct 4 9 1
...

Michal

2021-11-17 00:12:48

by Wei Yang

Subject: Re: [Patch v2] cgroup: pretty format /proc/cgroups

On Tue, Nov 16, 2021 at 07:00:17PM +0100, Michal Koutn? wrote:
>Hello.
>
>On Mon, Nov 15, 2021 at 01:12:53AM +0000, Wei Yang <[email protected]> wrote:
>> Let's align the title and value. After this patch, it looks like this.
>
>For machines this change may come as a surprise (so better not change
>it).
>
>For humans (for instance column from util-linux)
>
>$ column -t /proc/cgroups
>#subsys_name hierarchy num_cgroups enabled
>cpuset 11 2 1
>cpu 4 9 1
>cpuacct 4 9 1
>...
>

This is helpful, thanks.

>Michal

--
Wei Yang
Help you, Help me