Re: [-next v2 1/4] cpuset: remove redundant CS_ONLINE flag

[Tejun Heo]

On Wed, Aug 13, 2025 at 08:29:01AM +0000, Chen Ridong wrote:
> From: Chen Ridong <chenridong@xxxxxxxxxx>
> 
> The CS_ONLINE flag was introduced prior to the CSS_ONLINE flag in the
> cpuset subsystem. Currently, the flag setting sequence is as follows:
> 
> 1. cpuset_css_online() sets CS_ONLINE
> 2. css->flags gets CSS_ONLINE set
> ...
> 3. cgroup->kill_css sets CSS_DYING
> 4. cpuset_css_offline() clears CS_ONLINE
> 5. css->flags clears CSS_ONLINE
> 
> The is_cpuset_online() check currently occurs between steps 1 and 3.
> However, it would be equally safe to perform this check between steps 2
> and 3, as CSS_ONLINE provides the same synchronization guarantee as
> CS_ONLINE.
> 
> Since CS_ONLINE is redundant with CSS_ONLINE and provides no additional
> synchronization benefits, we can safely remove it to simplify the code.
> 
> Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
> Acked-by: Waiman Long <longman@xxxxxxxxxx>

Applied to cgroup/for-6.18.

Thanks.

-- 
tejun