sched/mmcid: Use cpumask_weighted_or()

Use cpumask_weighted_or() instead of cpumask_or() and cpumask_weight() on
the result, which walks the same bitmap twice. Results in 10-20% less
cycles, which reduces the runqueue lock hold time.

Signed-off-by: Thomas Gleixner <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Reviewed-by: Mathieu Desnoyers <[e-mail]>
Acked-by: Yury Norov (NVIDIA) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

kernel/sched/core.c

···
 static inline void mm_update_cpus_allowed(struct mm_struct *mm, const struct cpumask *affmsk)
 {
 	struct cpumask *mm_allowed;
+	unsigned int weight;
 
 	if (!mm)
 		return;
···
 	 */
 	guard(raw_spinlock)(&mm->mm_cid.lock);
 	mm_allowed = mm_cpus_allowed(mm);
-	cpumask_or(mm_allowed, mm_allowed, affmsk);
-	WRITE_ONCE(mm->mm_cid.nr_cpus_allowed, cpumask_weight(mm_allowed));
+	weight = cpumask_weighted_or(mm_allowed, mm_allowed, affmsk);
+	WRITE_ONCE(mm->mm_cid.nr_cpus_allowed, weight);
 }
 
 void sched_mm_cid_exit_signals(struct task_struct *t)