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

[Guopeng Zhang]

在 2026/9/21 12:29, Ridong Chen 写道:
> 
> 
> On 9/18/2026 6:23 PM, Guopeng Zhang wrote:
>> From: Guopeng Zhang <zhangguopeng@xxxxxxxxxx>
>>
>> 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@xxxxxxxxxx>
>> ---
>>   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@xxxxxxxxx>
> 

Thanks for the suggestion. That reads better.

I'll make one small change and use "the domain flag of isolcpus" here, since isolcpus also supports the nohz and managed_irq flags. I'll update the wording in v2 and add your Reviewed-by.

Thanks,
Guopeng