Re: [PATCH] cgroup/cpuset: Call rebuild_sched_domains() directly in hotplug

[Frederic Weisbecker <frederic@kernel.org>]

Le Wed, Mar 04, 2026 at 01:41:00PM -0500, Waiman Long a écrit :
> Besides deferring the call to housekeeping_update(), commit 6df415aa46ec
> ("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug
> to workqueue") also defers the rebuild_sched_domains() call to
> the workqueue. So a new offline CPU may still be in a sched domain
> or new online CPU not showing up in the sched domains for a short
> transition period. That could be a problem in some corner cases and
> can be the cause of a reported test failure[1]. Fix it by calling
> rebuild_sched_domains_cpuslocked() directly in hotplug as before. If
> isolated partition invalidation or recreation is being done, the
> housekeeping_update() call to update the housekeeping cpumasks will
> still be deferred to a workqueue.
> 
> In commit 3bfe47967191 ("cgroup/cpuset: Move
> housekeeping_update()/rebuild_sched_domains() together"),
> housekeeping_update() is called before rebuild_sched_domains() because
> it needs to access the HK_TYPE_DOMAIN housekeeping cpumask. That is now
> changed to use the static HK_TYPE_DOMAIN_BOOT cpumask as HK_TYPE_DOMAIN
> cpumask is now changeable at run time.  As a result, we can move the

But rebuild_sched_domains() will still handle the cpuset isolated partitions
somehow right? Sorry for the question, I'm a bit lost in the
partition_sched_domains() maze...

-- 
Frederic Weisbecker
SUSE Labs