On Sun, Jan 26, 2014 at 12:36 AM, Ingo Molnar <mi...@kernel.org> wrote:
>
> No, this message is printed in prefill_possible_map() which
> _generates_ cpu_possible_map, so '8' is the number of bits in
> cpu_possible_map.
>
> So the problem is that the counting of disabled but hotpluggable CPUs
> is over-eager. Since I haven't actually seen _true_ hotplug CPU
> hardware yet, I'd argue we do the change below - allocating space for
> never-present CPUs is stupid. If there's true hot-plug CPUs around
> that could come online after we've booted, then we want to know about
> them explicitly.
>
>
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index a32da80..75a351a 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1223,10 +1223,7 @@ __init void prefill_possible_map(void)
> i = setup_max_cpus ?: 1;
> if (setup_possible_cpus == -1) {
> possible = num_processors;
> -#ifdef CONFIG_HOTPLUG_CPU
> - if (setup_max_cpus)
> - possible += disabled_cpus;
> -#else
> +#ifndef CONFIG_HOTPLUG_CPU
> if (possible > i)
> possible = i;
> #endif
Agreed.
Most happens when one BIOS support different configuration.
Like system support 10 cores cpu and 15 cores cpus or system could be
configured with 4 sockets or 8 sockets
Thanks
Yinghai
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