2023-12-01 00:52:21

by Josh Don

[permalink] [raw]
Subject: [PATCH] cgroup: Fix documentation for cpu.idle

Two problems:
- cpu.idle cgroups show up with 0 weight, correct the
documentation to indicate this.
- cpu.idle has no entry describing it.

Signed-off-by: Josh Don <[email protected]>
---
Documentation/admin-guide/cgroup-v2.rst | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 3f85254f3cef..9debf02bcb39 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1093,7 +1093,11 @@ All time durations are in microseconds.
A read-write single value file which exists on non-root
cgroups. The default is "100".

- The weight in the range [1, 10000].
+ For non idle groups (cpu.idle = 0), the weight is in the
+ range [1, 10000].
+
+ If the cgroup has been configured to be SCHED_IDLE (cpu.idle = 1),
+ then the weight will show as a 0.

cpu.weight.nice
A read-write single value file which exists on non-root
@@ -1157,6 +1161,16 @@ All time durations are in microseconds.
values similar to the sched_setattr(2). This maximum utilization
value is used to clamp the task specific maximum utilization clamp.

+ cpu.idle
+ A read-write single value file which exists on non-root cgroups.
+ The default is 0.
+
+ This is the cgroup analog of the per-task SCHED_IDLE sched policy.
+ Setting this value to a 1 will make the scheduling policy of the
+ cgroup SCHED_IDLE. The threads inside the cgroup will retain their
+ own relative priorities, but the cgroup itself will be treated as
+ very low priority relative to its peers.
+


Memory
--
2.43.0.rc2.451.g8631bc7472-goog


2023-12-01 05:49:09

by Bagas Sanjaya

[permalink] [raw]
Subject: Re: [PATCH] cgroup: Fix documentation for cpu.idle

On Thu, Nov 30, 2023 at 04:52:03PM -0800, Josh Don wrote:
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 3f85254f3cef..9debf02bcb39 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1093,7 +1093,11 @@ All time durations are in microseconds.
> A read-write single value file which exists on non-root
> cgroups. The default is "100".
>
> - The weight in the range [1, 10000].
> + For non idle groups (cpu.idle = 0), the weight is in the
> + range [1, 10000].
> +
> + If the cgroup has been configured to be SCHED_IDLE (cpu.idle = 1),
> + then the weight will show as a 0.

This one LGTM.

>
> cpu.weight.nice
> A read-write single value file which exists on non-root
> @@ -1157,6 +1161,16 @@ All time durations are in microseconds.
> values similar to the sched_setattr(2). This maximum utilization
> value is used to clamp the task specific maximum utilization clamp.
>
> + cpu.idle
> + A read-write single value file which exists on non-root cgroups.
> + The default is 0.
> +
> + This is the cgroup analog of the per-task SCHED_IDLE sched policy.
"... cgroup analogy to ..."
> + Setting this value to a 1 will make the scheduling policy of the
> + cgroup SCHED_IDLE. The threads inside the cgroup will retain their
> + own relative priorities, but the cgroup itself will be treated as
> + very low priority relative to its peers.
> +
>

Thanks.

--
An old man doll... just what I always wanted! - Clara


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2023-12-01 15:14:59

by Jonathan Corbet

[permalink] [raw]
Subject: Re: [PATCH] cgroup: Fix documentation for cpu.idle

Bagas Sanjaya <[email protected]> writes:

> On Thu, Nov 30, 2023 at 04:52:03PM -0800, Josh Don wrote:
>> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
>> index 3f85254f3cef..9debf02bcb39 100644
>> --- a/Documentation/admin-guide/cgroup-v2.rst
>> +++ b/Documentation/admin-guide/cgroup-v2.rst
>> + cpu.idle
>> + A read-write single value file which exists on non-root cgroups.
>> + The default is 0.
>> +
>> + This is the cgroup analog of the per-task SCHED_IDLE sched policy.
> "... cgroup analogy to ..."
>> + Setting this value to a 1 will make the scheduling policy of the

Bagas, please stop this (again). The original wording is better than
your suggested "improvement".

jon

2023-12-01 16:50:06

by Tejun Heo

[permalink] [raw]
Subject: Re: [PATCH] cgroup: Fix documentation for cpu.idle

On Thu, Nov 30, 2023 at 04:52:03PM -0800, Josh Don wrote:
> Two problems:
> - cpu.idle cgroups show up with 0 weight, correct the
> documentation to indicate this.
> - cpu.idle has no entry describing it.
>
> Signed-off-by: Josh Don <[email protected]>

Applied to cgroup/for-6.8.

Thanks.

--
tejun

2023-12-02 01:38:33

by Bagas Sanjaya

[permalink] [raw]
Subject: Re: [PATCH] cgroup: Fix documentation for cpu.idle

On 12/1/23 22:14, Jonathan Corbet wrote:
> Bagas Sanjaya <[email protected]> writes:
>
>> On Thu, Nov 30, 2023 at 04:52:03PM -0800, Josh Don wrote:
>>> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
>>> index 3f85254f3cef..9debf02bcb39 100644
>>> --- a/Documentation/admin-guide/cgroup-v2.rst
>>> +++ b/Documentation/admin-guide/cgroup-v2.rst
>>> + cpu.idle
>>> + A read-write single value file which exists on non-root cgroups.
>>> + The default is 0.
>>> +
>>> + This is the cgroup analog of the per-task SCHED_IDLE sched policy.
>> "... cgroup analogy to ..."
>>> + Setting this value to a 1 will make the scheduling policy of the
>
> Bagas, please stop this (again). The original wording is better than
> your suggested "improvement".
>

OK, withdrawn!

And then,

Reviewed-by: Bagas Sanjaya <[email protected]>

Sorry for inconvenience.

--
An old man doll... just what I always wanted! - Clara