Re: [PATCH] Don't export sched_mc_power_savings in laptops

[Ingo Molnar <mingo@elte.hu>]

* Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> wrote:

>         Fix to prevent sched_mc_power_saving from being exported through sysfs
>         for multicore single socket (Laptop).
>     
>         CPU core map of the boot cpu should be equal to possible number
>         of cpus for single socket system.
>     
>         This fix has been developed at FOSS.in kernel workout.
>     
>         Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> 
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index 4850e4b..4adc830 100644
> --- a/arch/x86/include/asm/topology.h
> +++ b/arch/x86/include/asm/topology.h
> @@ -239,7 +239,7 @@ struct pci_bus;
>  void set_pci_bus_resources_arch_default(struct pci_bus *b);
>  
>  #ifdef CONFIG_SMP
> -#define mc_capable()			(boot_cpu_data.x86_max_cores > 1)
> +#define mc_capable()	(cpus_weight(per_cpu(cpu_core_map,0)) != nr_cpu_ids)

hm, dunno. sched_mc_power_savings should have no effect on single-socket 
systems, right? So the knob should have no effect.

	Ingo