Re: [PATCH 07/21] X86_64, UV: Disable Obsolete APIC ID fixup code used only on UV1

From: Ingo Molnar
Date: Tue May 03 2016 - 03:35:23 EST



* Mike Travis <travis@xxxxxxx> wrote:

> +config X86_UV1_SUPPORTED
> + bool "SGI Ultraviolet Series 1 Supported"
> + depends on X86_UV

So I still think it's much simpler if we simply eliminate this Kconfig
complication and have it all compatible. AFAICS the runtime impact on newer
systems comes down mostly to a single unlikely branch:

> static unsigned int x2apic_get_apic_id(unsigned long x)
> {
> - unsigned int id;
> + if (likely(!uv1_apic_driver))
> + return x;

Thanks,

Ingo