Re: [Xen-devel] [PATCH v4 02/12] x86: improve psr scheduling code

[Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>]

On Thu, Apr 09, 2015 at 10:01:53PM +0100, Andrew Cooper wrote:
> On 09/04/2015 10:18, Chao Peng wrote:
> > +static inline void psr_assoc_init(unsigned int cpu)
> > +{
> > +    struct psr_assoc *psra = &per_cpu(psr_assoc, cpu);
> > +
> > +    if ( psr_cmt_enabled() )
> > +        rdmsrl(MSR_IA32_PSR_ASSOC, psra->val);
> > +}
> 
> On further consideration, this would probably be better as a void
> function which used this_cpu() rather than per_cpu().
> 
> Absolutely nothing good can come of calling it with cpu !=
> smp_processor_id(), so we should avoid that situation arising in the
> first place.

Agreed.

> > +static void psr_cpu_init(unsigned int cpu)
> > +{
> > +    psr_assoc_init(cpu);
> > +}
> 
> This can also turn into a void helper.

This is, however, a little different. The next patch will add
cat_cpu_init() which will make use of this 'cpu' parameter. So do you
mean calling smp_processor_id() in cat_cpu_init() as well?

Thanks,
Chao

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