Re: [PATCH] x86_64: resize NR_IRQS for large machines (re-submit)

[Ingo Molnar <mingo@elte.hu>]

* Alan Mayer <ajm@sgi.com> wrote:

> On machines with very large numbers of cpus, tables that are 
> dimensioned by NR_IRQS get very large, especially the irq_desc table.  
> They are also very sparsely used.  When the cpu count is > 
> MAX_IO_APICS, use MAX_IO_APICS to set NR_IRQS, otherwise use NR_CPUS.

thanks Alan, applied this in place of the other patch.

this bit is still ugly:

> -#define NR_IRQS (NR_VECTORS + (32 *NR_CPUS))
> +#if NR_CPUS < MAX_IO_APICS
> +#define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
> +#else
> +#define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))
> +#endif
>  #define NR_IRQ_VECTORS NR_IRQS

but it doesnt really depart from the current status quo of huge 
[NR_IRQS] arrays either. Patches that make NR_IRQS a variable are 
welcome :)

	Ingo