Re: [PATCH 13/13] sched: Account for the number of preferred tasksrunning on a node when selecting a preferred node

From: Mel Gorman
Date: Thu Jul 04 2013 - 10:40:30 EST


On Thu, Jul 04, 2013 at 04:06:13PM +0200, Peter Zijlstra wrote:
> On Thu, Jul 04, 2013 at 02:54:15PM +0100, Mel Gorman wrote:
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 9247345..387f28d 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -863,9 +863,13 @@ find_idlest_cpu_node(int this_cpu, int nid)
> > load = weighted_cpuload(i);
> >
> > if (load < min_load) {
> > - /* Do not preempt a task running on a preferred node */
> > + /*
> > + * Do not preempt a task running on a preferred node or
> > + * tasks are are pinned to their current CPU
> > + */
> > struct task_struct *p = cpu_rq(i)->curr;
> > - if (p->numa_preferred_nid != nid) {
> > + if (p->numa_preferred_nid != nid &&
> > + cpumask_weight(tsk_cpus_allowed(p)) > 1) {
>
> We have p->nr_cpus_allowed for that.
>

/me slaps self

That's a bit easier to calculate, thanks.

--
Mel Gorman
SUSE Labs
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