Re: [PATCH cgroup/for-5.5] cgroup: remove cgroup_enable_task_cg_lists() optimization

[Tejun Heo]

On Thu, Oct 24, 2019 at 12:03:51PM -0700, Tejun Heo wrote:
> cgroup_enable_task_cg_lists() is used to lazyily initialize task
> cgroup associations on the first use to reduce fork / exit overheads
> on systems which don't use cgroup.  Unfortunately, locking around it
> has never been actually correct and its value is dubious given how the
> vast majority of systems use cgroup right away from boot.
> 
> This patch removes the optimization.  For now, replace the cg_list
> based branches with WARN_ON_ONCE()'s to be on the safe side.  We can
> simplify the logic further in the future.
> 
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Applying to cgroup/for-5.5.

Thanks.

-- 
tejun