linux-kernel - [PATCH 2/2] sched/deadline: Use cpumask_weight_and in dl_bw

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Message-ID: <20251014100342.978936-3-sshegde@linux.ibm.com>
Date: Tue, 14 Oct 2025 15:33:42 +0530
From: Shrikanth Hegde <sshegde@...ux.ibm.com>
To: peterz@...radead.org, juri.lelli@...hat.com, mingo@...hat.com,
        vincent.guittot@...aro.org
Cc: sshegde@...ux.ibm.com, linux-kernel@...r.kernel.org, rostedt@...dmis.org,
        dietmar.eggemann@....com, nico@...xnic.net
Subject: [PATCH 2/2] sched/deadline: Use cpumask_weight_and in dl_bw_cpus

- cpumask_subset(a,b) -> cpumask_weight(a) should be same as 
cpumask_weight_and(a,b)

- for_each_cpu_and(a,b) to count cpus could be replaced by
cpumask_weight_and(a,b)

No Functional Change. It could save a few cycles since cpumask_weight_and 
would be more efficient. Plus one less stack variable. 

Signed-off-by: Shrikanth Hegde <sshegde@...ux.ibm.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 8b7c4ee41fd8..a18f64b2e47c 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -125,20 +125,11 @@ 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)
-- 
2.47.3