Re: [PATCH 6/8] sched: Reschedule task on preferred NUMA node onceselected

[Peter Zijlstra]

On Wed, Jun 26, 2013 at 03:38:05PM +0100, Mel Gorman wrote:
> +static int
> +find_idlest_cpu_node(int this_cpu, int nid)
> +{
> +	unsigned long load, min_load = ULONG_MAX;
> +	int i, idlest_cpu = this_cpu;
> +
> +	BUG_ON(cpu_to_node(this_cpu) == nid);
> +
> +	for_each_cpu(i, cpumask_of_node(nid)) {
> +		load = weighted_cpuload(i);
> +
> +		if (load < min_load) {
> +			struct task_struct *p;
> +
> +			/* Do not preempt a task running on its preferred node */
> +			struct rq *rq = cpu_rq(i);
> +			local_irq_disable();
> +			raw_spin_lock(&rq->lock);

raw_spin_lock_irq() ?

> +			p = rq->curr;
> +			if (p->numa_preferred_nid != nid) {
> +				min_load = load;
> +				idlest_cpu = i;
> +			}
> +			raw_spin_unlock(&rq->lock);
> +			local_irq_disable();
> +		}
> +	}
> +
> +	return idlest_cpu;
> +}
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