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Commit eae0c9df authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

sched: Fix and clean up rate-limit newidle code 



Commit 1b9508f6, "Rate-limit newidle" has been confirmed to fix
the netperf UDP loopback regression reported by Alex Shi.

This is a cleanup and a fix:

 - moved to a more out of the way spot

 - fix to ensure that balancing doesn't try to balance
   runqueues which haven't gone online yet, which can
   mess up CPU enumeration during boot.

Reported-by: default avatarAlex Shi <alex.shi@intel.com>
Reported-by: default avatarZhang, Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org> # .32.x: a1f84a3a: sched: Check for an idle shared cache
Cc: <stable@kernel.org> # .32.x: 1b9508f6: sched: Rate-limit newidle
Cc: <stable@kernel.org> # .32.x: fd210738: sched: Fix affinity logic
Cc: <stable@kernel.org> # .32.x
LKML-Reference: <1257821402.5648.17.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d8c80ce0

kernel/sched.c

+15 −13
Original line number Diff line number Diff line
@@ -2354,17 +2354,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, 
	if (rq != orig_rq)

		update_rq_clock(rq);



	if (rq->idle_stamp) {

		u64 delta = rq->clock - rq->idle_stamp;

		u64 max = 2*sysctl_sched_migration_cost;



		if (delta > max)

			rq->avg_idle = max;

		else

			update_avg(&rq->avg_idle, delta);

		rq->idle_stamp = 0;

	}



	WARN_ON(p->state != TASK_WAKING);

	cpu = task_cpu(p);
@@ -2421,6 +2410,17 @@ out_running: 
#ifdef CONFIG_SMP

	if (p->sched_class->task_wake_up)

		p->sched_class->task_wake_up(rq, p);



	if (unlikely(rq->idle_stamp)) {

		u64 delta = rq->clock - rq->idle_stamp;

		u64 max = 2*sysctl_sched_migration_cost;



		if (delta > max)

			rq->avg_idle = max;

		else

			update_avg(&rq->avg_idle, delta);

		rq->idle_stamp = 0;

	}

#endif

out:

	task_rq_unlock(rq, &flags);
@@ -4098,7 +4098,7 @@ static int load_balance(int this_cpu, struct rq *this_rq, 
	unsigned long flags;

	struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);



	cpumask_setall(cpus);

	cpumask_copy(cpus, cpu_online_mask);



	/*

	 * When power savings policy is enabled for the parent domain, idle
@@ -4261,7 +4261,7 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) 
	int all_pinned = 0;

	struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);



	cpumask_setall(cpus);

	cpumask_copy(cpus, cpu_online_mask);



	/*

	 * When power savings policy is enabled for the parent domain, idle
@@ -9522,6 +9522,8 @@ void __init sched_init(void) 
		rq->cpu = i;

		rq->online = 0;

		rq->migration_thread = NULL;

		rq->idle_stamp = 0;

		rq->avg_idle = 2*sysctl_sched_migration_cost;

		INIT_LIST_HEAD(&rq->migration_queue);

		rq_attach_root(rq, &def_root_domain);

#endif