Re: [-next v2 4/4] cpuset: add helpers for cpus read and cpuset_mutex locks

[Chen Ridong]

On 2025/8/14 4:09, Waiman Long wrote:
> On 8/13/25 4:29 AM, Chen Ridong wrote:
>> From: Chen Ridong <chenridong@xxxxxxxxxx>
>>
>> cpuset: add helpers for cpus_read_lock and cpuset_mutex
>>
>> Replace repetitive locking patterns with new helpers:
>> - cpus_read_cpuset_lock()
>> - cpus_read_cpuset_unlock()
>>
>> This makes the code cleaner and ensures consistent lock ordering.
>>
>> Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
>> ---
>>   kernel/cgroup/cpuset-internal.h |  2 ++
>>   kernel/cgroup/cpuset-v1.c       | 12 +++------
>>   kernel/cgroup/cpuset.c          | 48 +++++++++++++++------------------
>>   3 files changed, 28 insertions(+), 34 deletions(-)
>>
>> diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h
>> index 75b3aef39231..6fb00c96044d 100644
>> --- a/kernel/cgroup/cpuset-internal.h
>> +++ b/kernel/cgroup/cpuset-internal.h
>> @@ -276,6 +276,8 @@ int cpuset_update_flag(cpuset_flagbits_t bit, struct cpuset *cs, int turning_on)
>>   ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
>>                       char *buf, size_t nbytes, loff_t off);
>>   int cpuset_common_seq_show(struct seq_file *sf, void *v);
>> +void cpus_read_cpuset_lock(void);
>> +void cpus_read_cpuset_unlock(void);
> 
> The names are not intuitive. I would prefer just extend the cpuset_lock/unlock to include
> cpus_read_lock/unlock and we use cpuset_lock/unlock consistently in the cpuset code. Also, there is
> now no external user of cpuset_lock/unlock, we may as well remove them from include/linux/cpuset.h.
> 
> Cheers,
> Longman

I like the idea and have considered it.
However, I noticed that cpuset_locked is being used in __sched_setscheduler.

-- 
Best regards,
Ridong