Re: [External] Re: [PATCH] sched/core: Avoid selecting the task that is throttled to run when core-sched enable

[Hao Jia]

On 2023/3/20 Peter Zijlstra wrote:
> On Thu, Mar 16, 2023 at 04:18:06PM +0800, Hao Jia wrote:
>
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index af017e038b48..27cb06e19b12 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -261,36 +261,51 @@ void sched_core_dequeue(struct rq *rq, struct task_struct *p, int flags)
> >   		resched_curr(rq);
> >   }
> >   
> > +static int sched_task_is_throttled(struct task_struct *p, int cpu)
> >   {
> > +	if (p->sched_class->task_is_throttled)
> > +		return p->sched_class->task_is_throttled(p, cpu);
> >   
> > +	return 0;
> >   }
> >   
> >   static struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie)
> >   {
> >   	struct rb_node *node = &p->core_node;
> > +	int cpu = task_cpu(p);
> > +
> > +	do {
> > +		node = rb_next(node);
> > +		if (!node)
> > +			return NULL;
> > +
> > +		p = container_of(node, struct task_struct, core_node);
>
> I've changed this to __node_2_sc() to match the rest. It looks to have
> been randomly not using it.

OK, Thanks!
> > +		if (p->core_cookie != cookie)
> > +			return NULL;
> > +	} while (sched_task_is_throttled(p, cpu));
> > +
> > +	return p;
> > +}
> >   
> > +/*
> > + * Find left-most (aka, highest priority) and unthrottled task matching @cookie.
> > + * If no suitable task is found, NULL will be returned.
> > + */
> > +static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie)
> > +{
> > +	struct task_struct *p;
> > +	struct rb_node *node;
> > +
> > +	node = rb_find_first((void *)cookie, &rq->core_tree, rb_sched_core_cmp);
> >   	if (!node)
> >   		return NULL;
> >   
> > +	p = __node_2_sc(node);
> > +	if (!sched_task_is_throttled(p, rq->cpu))
> > +		return p;
> > +
> > +	return sched_core_next(p, cookie);
> >   }
> >   
> >   /*
>
> OK, fair enough.

Thanks for your review. Do I need to modify to send V2 patch?

Thanks,
Hao
>