Commit 7170509c authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched: Simplify sched_core_cpu_{starting,deactivate}() 



Use guards to reduce gotos and simplify control flow.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarValentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20230801211812.371787909@infradead.org
parent b4e1fa1e

kernel/sched/core.c

+12 −15
Original line number Diff line number Diff line
@@ -6400,20 +6400,24 @@ static void queue_core_balance(struct rq *rq) 
	queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance);

}



DEFINE_LOCK_GUARD_1(core_lock, int,

		    sched_core_lock(*_T->lock, &_T->flags),

		    sched_core_unlock(*_T->lock, &_T->flags),

		    unsigned long flags)



static void sched_core_cpu_starting(unsigned int cpu)

{

	const struct cpumask *smt_mask = cpu_smt_mask(cpu);

	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;

	unsigned long flags;

	int t;



	sched_core_lock(cpu, &flags);

	guard(core_lock)(&cpu);



	WARN_ON_ONCE(rq->core != rq);



	/* if we're the first, we'll be our own leader */

	if (cpumask_weight(smt_mask) == 1)

		goto unlock;

		return;



	/* find the leader */

	for_each_cpu(t, smt_mask) {
@@ -6427,7 +6431,7 @@ static void sched_core_cpu_starting(unsigned int cpu) 
	}



	if (WARN_ON_ONCE(!core_rq)) /* whoopsie */

		goto unlock;

		return;



	/* install and validate core_rq */

	for_each_cpu(t, smt_mask) {
@@ -6438,29 +6442,25 @@ static void sched_core_cpu_starting(unsigned int cpu) 


		WARN_ON_ONCE(rq->core != core_rq);

	}



unlock:

	sched_core_unlock(cpu, &flags);

}



static void sched_core_cpu_deactivate(unsigned int cpu)

{

	const struct cpumask *smt_mask = cpu_smt_mask(cpu);

	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;

	unsigned long flags;

	int t;



	sched_core_lock(cpu, &flags);

	guard(core_lock)(&cpu);



	/* if we're the last man standing, nothing to do */

	if (cpumask_weight(smt_mask) == 1) {

		WARN_ON_ONCE(rq->core != rq);

		goto unlock;

		return;

	}



	/* if we're not the leader, nothing to do */

	if (rq->core != rq)

		goto unlock;

		return;



	/* find a new leader */

	for_each_cpu(t, smt_mask) {
@@ -6471,7 +6471,7 @@ static void sched_core_cpu_deactivate(unsigned int cpu) 
	}



	if (WARN_ON_ONCE(!core_rq)) /* impossible */

		goto unlock;

		return;



	/* copy the shared state to the new leader */

	core_rq->core_task_seq             = rq->core_task_seq;
@@ -6493,9 +6493,6 @@ static void sched_core_cpu_deactivate(unsigned int cpu) 
		rq = cpu_rq(t);

		rq->core = core_rq;

	}



unlock:

	sched_core_unlock(cpu, &flags);

}



static inline void sched_core_cpu_dying(unsigned int cpu)