Re: false nr_running check in load balance?

[Peter Zijlstra <peterz@infradead.org>]

On Tue, Aug 13, 2013 at 12:45:12PM +0800, Lei Wen wrote:
> > Not quite right; I think you need busiest->cfs.h_nr_running.
> > cfs.nr_running is the number of entries running in this 'group'. If
> > you've got nested groups like:
> >
> >  'root'
> >    \
> >    'A'
> >    / \
> >   t1 t2
> >
> > root.nr_running := 1 'A', even though you've got multiple running tasks.
> >
> 
> You're absolutely right for this. :)
> I miss it for not considering the group case...
> 
> Then do you think it is necessary to do below change in load_balance() code?
>  -       if (busiest->nr_running > 1) {
>  +       if (busiest->cfs.h_nr_running > 1) {
> 

Yes I think that would be fine.