Re: [PATCH 08/18] sched: Reschedule task on preferred NUMA node onceselected

From: Srikar Dronamraju
Date: Wed Jul 31 2013 - 05:38:24 EST


* Mel Gorman <mgorman@xxxxxxx> [2013-07-31 10:07:27]:

> On Wed, Jul 17, 2013 at 09:31:05AM +0800, Hillf Danton wrote:
> > On Mon, Jul 15, 2013 at 11:20 PM, Mel Gorman <mgorman@xxxxxxx> 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);
> > > +
> > > + rcu_read_lock();
> > > + for_each_cpu(i, cpumask_of_node(nid)) {
> >
> > Check allowed CPUs first if task is given?
> >
>
> If the task is not allowed to run on the CPUs for that node then how
> were the NUMA hinting faults recorded?
>

But still we could check if the task is allowed to run on a cpu before we
capture the load of the cpu. This would avoid us trying to select a cpu
whose load is low but which cannot run this task.

> --
> Mel Gorman
> SUSE Labs
>

--
Thanks and Regards
Srikar Dronamraju

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