Merge pull request #220 from sched-ext/fix_hotplug

scx: Flip order of scx_rq_{de}activate()

kernel/sched/core.c

@@ -9777,6 +9777,8 @@ int sched_cpu_activate(unsigned int cpu)
 		cpuset_cpu_active();
 	}
 
+	scx_rq_activate(rq);
+
 	/*
 	 * Put the rq online, if not already. This happens:
 	 *
@@ -9792,7 +9794,6 @@ int sched_cpu_activate(unsigned int cpu)
 		set_rq_online(rq);
 	}
 	rq_unlock_irqrestore(rq, &rf);
-	scx_rq_activate(rq);
 
 	return 0;
 }
@@ -9831,14 +9832,15 @@ int sched_cpu_deactivate(unsigned int cpu)
 	 */
 	synchronize_rcu();
 
-	scx_rq_deactivate(rq);
 	rq_lock_irqsave(rq, &rf);
 	if (rq->rd) {
 		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
 		set_rq_offline(rq);
 	}
 	rq_unlock_irqrestore(rq, &rf);
 
+	scx_rq_deactivate(rq);
+
 #ifdef CONFIG_SCHED_SMT
 	/*
 	 * When going down, decrement the number of cores with SMT present.