Re: [PATCH] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512

[Russell King (Oracle)]

On Thu, Dec 14, 2023 at 04:05:56PM -0800, Christoph Lameter (Ampere) wrote:
> Index: linux/arch/arm64/Kconfig
> ===================================================================
> --- linux.orig/arch/arm64/Kconfig
> +++ linux/arch/arm64/Kconfig
> @@ -1407,7 +1407,21 @@ config SCHED_SMT
>   config NR_CPUS
>   	int "Maximum number of CPUs (2-4096)"
>   	range 2 4096

I think your mailer got to your patch and messed up the white space.
There are two spaces before each of these lines rather than the usual
one.

> -	default "256"
> +	default 512
> +
> +#
> +# Determines the placement of cpumasks.
> +#
> +# With CPUMASK_OFFSTACK the cpumasks are dynamically allocated.
> +# Useful for machines with lots of core because it avoids increasing
> +# the size of many of the data structures in the kernel.
> +#
> +# If this is off then the cpumasks have a static sizes and are
> +# embedded within data structures.
> +#
> +config CPUMASK_OFFSTACK
> +	def_bool y
> +	depends on NR_CPUS > 256

Should that be ">= 256" ?

> 
>   config HOTPLUG_CPU
>   	bool "Support for hot-pluggable CPUs"

Same here.

-- 
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