RE: [Xen-devel] [PATCH] [retry 1] 1/3 Refactor Xen support for Intel Turbo boost

["Langsdorf, Mark" <mark.langsdorf@xxxxxxx>]

> > @@ -328,6 +327,7 @@
> >      char scaling_governor[CPUFREQ_NAME_LEN];
> >      uint32_t scaling_max_freq;
> >      uint32_t scaling_min_freq;
> > +    int32_t turbo_enabled;
> > 
> >      /* for specific governor */
> >      union {
> > 
> 
> I would like to change this as following, to keep hypercall 
> interface backward compatible.  And adding padding allows 
> future extension.
> 
> diff -r 91232efdcfdc xen/include/public/sysctl.h
> --- a/xen/include/public/sysctl.h       Tue Mar 30 08:36:41 2010 +0100
> +++ b/xen/include/public/sysctl.h       Wed Mar 31 15:58:48 2010 +0800
> @@ -333,7 +333,10 @@ struct xen_get_cpufreq_para {
>      union {
>          struct  xen_userspace userspace;
>          struct  xen_ondemand ondemand;
> +        uint8_t pad[32];
>      } u;
> +
> +    int32_t turbo_enabled;
>  };
> 
> And you may want to change "struct xc_get_cpufreq_para" as well.

I don't think you need to pad it that way.  struct xen_sysctl 
already has a 128 byte pad defined for it.

Also, doing so triggers a build error macro in 
arch/x86/setup.c line 915.

-Mark Langsdorf
Operating System Research Center
AMD


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