Re: [PATCH v2] credit: generalize __vcpu_has_soft_affinity()

[Dario Faggioli <dario.faggioli@citrix.com>]

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On Fri, 2015-03-06 at 13:32 +0000, Jan Beulich wrote:
> >>> On 06.03.15 at 14:23, <dario.faggioli@citrix.com> wrote:
> > Which means that, yes, this part of the condition must loose the '!', or
> > have the arguments of the call to cpumask_subset() switched. I
> > personally prefer the former:
> > 
> >     return !cpumask_subset(cpupool_online_cpumask(vc->domain->cpupool),
> >                            vc->cpu_soft_affinity) &&
> >            cpumask_subset(vc->cpu_soft_affinity, vc->cpu_hard_affinity) &&
> >            cpumask_intersects(vc->cpu_soft_affinity, mask);
> 
> The form without ! and with operands swapped isn't correct afaict,
> since subset(x,y) is not the same as !subset(y,x).
>
I was thinking to loose the '!' and don't swap them, but...

> In particular
> when the two are identical, they are also subsets of one another.
>
... that is true, and is not the only issue the variant I suggested
above would introduce. So forget it, '!' it is. :-)

Dario

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