Re: [PATCH] x86: use nr_cpus in max_nr_irqs()

From: Mike Travis
Date: Mon Jan 12 2009 - 13:32:16 EST


Yinghai Lu wrote:
> Impact: get more small nr_irqs
>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>
> ---
> arch/x86/include/asm/apicdef.h | 7 +------
> arch/x86/include/asm/irq_vectors.h | 4 ++--
> 2 files changed, 3 insertions(+), 8 deletions(-)
>
> Index: linux-2.6/arch/x86/include/asm/irq_vectors.h
> ===================================================================
> --- linux-2.6.orig/arch/x86/include/asm/irq_vectors.h
> +++ linux-2.6/arch/x86/include/asm/irq_vectors.h
> @@ -122,8 +122,8 @@
>
> /* defined as a macro so nr_irqs = max_nr_irqs(nr_cpu_ids) can be used */
> # define max_nr_irqs(nr_cpus) \
> - ((8 * nr_cpus) > (32 * MAX_IO_APICS) ? \
> - (NR_VECTORS + (8 * NR_CPUS)) : \
> + ((8 * (nr_cpus)) > (32 * MAX_IO_APICS) ? \
> + (NR_VECTORS + (8 * (nr_cpus)) : \
> (NR_VECTORS + (32 * MAX_IO_APICS))) \
>
> # define NR_IRQS max_nr_irqs(NR_CPUS)

Did I really miss that? I guess the reduction from 33024 to 4352
was sufficient for me... ;-)

Hey, a question... Can I determine what the maximum apic id would be?
Right now it's fixed at 32k but that seems high even for 4096 cpus?
(MAX_APICS].

Thanks!
Mike

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