Re: [RFC PATCH 3/7] sched/fair: Handle unthrottle path for task based throttle

[K Prateek Nayak]

On 3/14/2025 9:23 AM, K Prateek Nayak wrote:

[..snip..]

> > +    /* Re-enqueue the tasks that have been throttled at this level. */
> > +    list_for_each_entry_safe(p, tmp, &cfs_rq->throttled_limbo_list,
> > throttle_node) {
> > +        list_del_init(&p->throttle_node);
> > +        /*
> > +         * FIXME: p may not be allowed to run on this rq anymore
> > +         * due to affinity change while p is throttled.
> > +         */
>
> Using dequeue_task_fair() for throttle should ensure that the core now
> sees task_on_rq_queued() which should make it go throgh a full dequeue
> cycle which will remove the task from the "throttled_limbo_list" and
> the enqueue should put it back on the correct runqueue.
>
> Is the above comment inaccurate with your changes or did I miss
> something?

Please ignore this, I just reached Patch 5. Sorry for the noise.

> > +        enqueue_task_fair(rq_of(cfs_rq), p, ENQUEUE_WAKEUP);
> > +    }
> > +
> > +    /* Add cfs_rq with load or one or more already running entities to the list */
> > +    if (!cfs_rq_is_decayed(cfs_rq))
> > +        list_add_leaf_cfs_rq(cfs_rq);
> > +
> >       return 0;
> >   }

--
Thanks and Regards,
Prateek