Commit 6fb45460 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Simplify tg_set_cfs_bandwidth() 



Use guards to reduce gotos and simplify control flow.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent fa614b4f

include/linux/cpu.h

+2 −0
Original line number Diff line number Diff line
@@ -153,6 +153,8 @@ static inline int remove_cpu(unsigned int cpu) { return -EPERM; } 
static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }

#endif	/* !CONFIG_HOTPLUG_CPU */



DEFINE_LOCK_GUARD_0(cpus_read_lock, cpus_read_lock(), cpus_read_unlock())



#ifdef CONFIG_PM_SLEEP_SMP

extern int freeze_secondary_cpus(int primary);

extern void thaw_secondary_cpus(void);

kernel/sched/core.c

+19 −19
Original line number Diff line number Diff line
@@ -10802,11 +10802,12 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota, 
	 * Prevent race between setting of cfs_rq->runtime_enabled and

	 * unthrottle_offline_cfs_rqs().

	 */

	cpus_read_lock();

	mutex_lock(&cfs_constraints_mutex);

	guard(cpus_read_lock)();

	guard(mutex)(&cfs_constraints_mutex);



	ret = __cfs_schedulable(tg, period, quota);

	if (ret)

		goto out_unlock;

		return ret;



	runtime_enabled = quota != RUNTIME_INF;

	runtime_was_enabled = cfs_b->quota != RUNTIME_INF;
@@ -10816,39 +10817,38 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota, 
	 */

	if (runtime_enabled && !runtime_was_enabled)

		cfs_bandwidth_usage_inc();

	raw_spin_lock_irq(&cfs_b->lock);



	scoped_guard (raw_spinlock_irq, &cfs_b->lock) {

		cfs_b->period = ns_to_ktime(period);

		cfs_b->quota = quota;

		cfs_b->burst = burst;



		__refill_cfs_bandwidth_runtime(cfs_b);



	/* Restart the period timer (if active) to handle new period expiry: */

		/*

		 * Restart the period timer (if active) to handle new

		 * period expiry:

		 */

		if (runtime_enabled)

			start_cfs_bandwidth(cfs_b);



	raw_spin_unlock_irq(&cfs_b->lock);

	}



	for_each_online_cpu(i) {

		struct cfs_rq *cfs_rq = tg->cfs_rq[i];

		struct rq *rq = cfs_rq->rq;

		struct rq_flags rf;



		rq_lock_irq(rq, &rf);

		guard(rq_lock_irq)(rq);

		cfs_rq->runtime_enabled = runtime_enabled;

		cfs_rq->runtime_remaining = 0;



		if (cfs_rq->throttled)

			unthrottle_cfs_rq(cfs_rq);

		rq_unlock_irq(rq, &rf);

	}



	if (runtime_was_enabled && !runtime_enabled)

		cfs_bandwidth_usage_dec();

out_unlock:

	mutex_unlock(&cfs_constraints_mutex);

	cpus_read_unlock();



	return ret;

	return 0;

}



static int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us)