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Commit 055a0086 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

sched: Fix/add missing update_rq_clock() calls 



kthread_bind(), migrate_task() and sched_fork were missing
updates, and try_to_wake_up() was updating after having already
used the stale clock.

Aside from preventing potential latency hits, there' a side
benefit in that early boot printk time stamps become monotonic.

Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1258020464.6491.2.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
LKML-Reference: <new-submission>
parent aa021baa

kernel/sched.c

+12 −5
Original line number Diff line number Diff line
@@ -2017,6 +2017,7 @@ void kthread_bind(struct task_struct *p, unsigned int cpu) 
	}



	spin_lock_irqsave(&rq->lock, flags);

	update_rq_clock(rq);

	set_task_cpu(p, cpu);

	p->cpus_allowed = cpumask_of_cpu(cpu);

	p->rt.nr_cpus_allowed = 1;
@@ -2115,6 +2116,7 @@ migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) 
	 * it is sufficient to simply update the task's cpu field.

	 */

	if (!p->se.on_rq && !task_running(rq, p)) {

		update_rq_clock(rq);

		set_task_cpu(p, dest_cpu);

		return 0;

	}
@@ -2376,14 +2378,15 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, 
	task_rq_unlock(rq, &flags);



	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags);

	if (cpu != orig_cpu)

	if (cpu != orig_cpu) {

		local_irq_save(flags);

		rq = cpu_rq(cpu);

		update_rq_clock(rq);

		set_task_cpu(p, cpu);



		local_irq_restore(flags);

	}

	rq = task_rq_lock(p, &flags);



	if (rq != orig_rq)

		update_rq_clock(rq);



	WARN_ON(p->state != TASK_WAKING);

	cpu = task_cpu(p);
@@ -2545,6 +2548,7 @@ static void __sched_fork(struct task_struct *p) 
void sched_fork(struct task_struct *p, int clone_flags)

{

	int cpu = get_cpu();

	unsigned long flags;



	__sched_fork(p);
@@ -2581,7 +2585,10 @@ void sched_fork(struct task_struct *p, int clone_flags) 
#ifdef CONFIG_SMP

	cpu = p->sched_class->select_task_rq(p, SD_BALANCE_FORK, 0);

#endif

	local_irq_save(flags);

	update_rq_clock(cpu_rq(cpu));

	set_task_cpu(p, cpu);

	local_irq_restore(flags);



#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)

	if (likely(sched_info_on()))