Commit 4eb054f9 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched: Simplify wake_up_if_idle() 



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/20230801211812.032678917@infradead.org
parent 5bb76f1d

kernel/sched/core.c

+6 −14
Original line number Diff line number Diff line
@@ -3939,21 +3939,13 @@ static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags 
void wake_up_if_idle(int cpu)

{

	struct rq *rq = cpu_rq(cpu);

	struct rq_flags rf;



	rcu_read_lock();



	if (!is_idle_task(rcu_dereference(rq->curr)))

		goto out;



	rq_lock_irqsave(rq, &rf);

	guard(rcu)();

	if (is_idle_task(rcu_dereference(rq->curr))) {

		guard(rq_lock_irqsave)(rq);

		if (is_idle_task(rq->curr))

			resched_curr(rq);

	/* Else CPU is not idle, do nothing here: */

	rq_unlock_irqrestore(rq, &rf);



out:

	rcu_read_unlock();

	}

}



bool cpus_share_cache(int this_cpu, int that_cpu)

kernel/sched/sched.h

+15 −0
Original line number Diff line number Diff line
@@ -1705,6 +1705,21 @@ rq_unlock(struct rq *rq, struct rq_flags *rf) 
	raw_spin_rq_unlock(rq);

}



DEFINE_LOCK_GUARD_1(rq_lock, struct rq,

		    rq_lock(_T->lock, &_T->rf),

		    rq_unlock(_T->lock, &_T->rf),

		    struct rq_flags rf)



DEFINE_LOCK_GUARD_1(rq_lock_irq, struct rq,

		    rq_lock_irq(_T->lock, &_T->rf),

		    rq_unlock_irq(_T->lock, &_T->rf),

		    struct rq_flags rf)



DEFINE_LOCK_GUARD_1(rq_lock_irqsave, struct rq,

		    rq_lock_irqsave(_T->lock, &_T->rf),

		    rq_unlock_irqrestore(_T->lock, &_T->rf),

		    struct rq_flags rf)



static inline struct rq *

this_rq_lock_irq(struct rq_flags *rf)

	__acquires(rq->lock)