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Date:   Tue, 6 Oct 2020 16:20:04 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Juri Lelli <juri.lelli@redhat.com>
Cc:     tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org,
        bigeasy@linutronix.de, qais.yousef@arm.com, swood@redhat.com,
        valentin.schneider@arm.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        mgorman@suse.de, bristot@redhat.com, vincent.donnefort@arm.com,
        tj@kernel.org
Subject: Re: [PATCH -v2 12/17] sched,rt: Use cpumask_any*_distribute()
Message-ID: <20201006142004.GX2628@hirez.programming.kicks-ass.net>
References: <20201005145717.346020688@infradead.org>
 <20201005150922.156231026@infradead.org>
 <20201006140926.GI4352@localhost.localdomain>
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On Tue, Oct 06, 2020 at 04:09:26PM +0200, Juri Lelli wrote:

> > --- a/kernel/sched/deadline.c
> > +++ b/kernel/sched/deadline.c
> > @@ -2001,7 +2001,7 @@ static int find_later_rq(struct task_str
> >  	if (this_cpu != -1)
> >  		return this_cpu;
> >  
> > -	cpu = cpumask_any(later_mask);
> > +	cpu = cpumask_any_distribute(later_mask);
> >  	if (cpu < nr_cpu_ids)
> >  		return cpu;
> 
> Think we can use cpumask_any_and_distribute() with later_mask for
> deadline as well inside the for_each_domain loop as you do for rt below.

Ah, indeed.. I missed it because it is cpumask_first, instead of
cpumask_any as with rt.

I folded the below.

---
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1981,8 +1981,8 @@ static int find_later_rq(struct task_str
 				return this_cpu;
 			}
 
-			best_cpu = cpumask_first_and(later_mask,
-							sched_domain_span(sd));
+			best_cpu = cpumask_any_and_distribute(later_mask,
+							      sched_domain_span(sd));
 			/*
 			 * Last chance: if a CPU being in both later_mask
 			 * and current sd span is valid, that becomes our