Re: [PATCH 1/2] docs: cgroup-v2: Describe boot-isolated CPUs in cpuset.cpus.isolated

[Ridong Chen <ridong.chen@linux.dev>]

On 9/18/2026 6:23 PM, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
> 
> cpuset.cpus.isolated is documented as empty when no isolated partition
> exists. This is not true when CPUs are isolated at boot with
> isolcpus=domain. cpuset_init() adds those CPUs to the isolated mask,
> and isolcpus=<cpu-list> uses domain isolation by default. They remain
> listed after a partition using them is released.
> 
> Document the boot-isolated CPUs as well.
> 
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
> ---
>   Documentation/admin-guide/cgroup-v2.rst | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
> index 2ec582985b5b..272e9f2432bd 100644
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -2625,9 +2625,11 @@ Cpuset Interface Files
>     cpuset.cpus.isolated
>   	A read-only and root cgroup only multiple values file.
>   
> -	This file shows the set of all isolated CPUs used in existing
> -	isolated partitions. It will be empty if no isolated partition
> -	is created.
> +	This file shows CPUs isolated from scheduler domains by
> +	isolated cpuset partitions or at boot with "isolcpus=domain"
> +	(including the default "isolcpus=<cpu-list>" form).  CPUs
> +	isolated at boot remain listed after any partition using them
> +	is released.
>   
>     cpuset.cpus.partition
>   	A read-write single value file which exists on non-root

Could we keep that terminology and avoid repeating "isolated"? Something like:

       This file shows the set of all isolated CPUs used in existing
       isolated partitions or isolated at boot time via "isolcpus".
       The latter remain listed even after any partition using them
       is released.

With that:

Reviewed-by: Ridong Chen <ridong.chen@linux.dev>

-- 
Best regards
Ridong