Re: [PATCH v10 3/9] cpuset: Simulate auto-off of sched.domain_root at cgroup removal

Peter Zijlstra
2018-06-20T14:12:04Z

On Mon, Jun 18, 2018 at 12:14:02PM +0800, Waiman Long wrote:
> @@ -1058,7 +1060,12 @@ static int update_reserved_cpumask(struct cpuset *cpuset,
> * Check if any CPUs in addmask or delmask are in the effective_cpus
> * of a sibling cpuset. The implied cpu_exclusive of a scheduling
> * domain root will ensure there are no overlap in cpus_allowed.
> + *
> + * This check is skipped if the cpuset is dying.

Comments that state what the code does are mostly useless; please
explain _why_ if anything.

> */
> + if (dying)
> + goto updated_reserved_cpus;
> +
> rcu_read_lock();
> cpuset_for_each_child(sibling, pos_css, parent) {
> if ((sibling == cpuset) || !(sibling->css.flags & CSS_ONLINE))