linux-kernel - Re: [PATCH] sched/deadline: simplify dl_bw_cpus() using cpumask_weight

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Message-ID: <20230613131651.GA536267@lorien.usersys.redhat.com>
Date:   Tue, 13 Jun 2023 09:16:51 -0400
From:   Phil Auld <pauld@...hat.com>
To:     Miaohe Lin <linmiaohe@...wei.com>
Cc:     mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
        bristot@...hat.com, vschneid@...hat.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sched/deadline: simplify dl_bw_cpus() using
 cpumask_weight_and()

On Tue, Jun 13, 2023 at 08:19:22PM +0800 Miaohe Lin wrote:
> On 2023/5/22 19:56, Miaohe Lin wrote:
> > cpumask_weight_and() can be used to count of bits both in rd->span and
> > cpu_active_mask. No functional change intended.
> > 
> > Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> 
> friendly ping... :)

This looks reasonable, and better, to me.

Reviewed-by: Phil Auld <pauld@...hat.com>

> 
> > ---
> >  kernel/sched/deadline.c | 11 +----------
> >  1 file changed, 1 insertion(+), 10 deletions(-)
> > 
> > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> > index 166c3e6eae61..fe983ed7bb12 100644
> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -110,20 +110,11 @@ static inline struct dl_bw *dl_bw_of(int i)
> >  static inline int dl_bw_cpus(int i)
> >  {
> >  	struct root_domain *rd = cpu_rq(i)->rd;
> > -	int cpus;
> >  
> >  	RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
> >  			 "sched RCU must be held");
> >  
> > -	if (cpumask_subset(rd->span, cpu_active_mask))
> > -		return cpumask_weight(rd->span);
> > -
> > -	cpus = 0;
> > -
> > -	for_each_cpu_and(i, rd->span, cpu_active_mask)
> > -		cpus++;
> > -
> > -	return cpus;
> > +	return cpumask_weight_and(rd->span, cpu_active_mask);
> >  }
> >  
> >  static inline unsigned long __dl_bw_capacity(const struct cpumask *mask)
> > 
> 

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