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SubjectRe: [PATCH] Do not force shutdown/reboot to boot cpu.
On 04/08/2013 08:57 AM, Ingo Molnar wrote:
>
> I think the original commit:
>
> f96972f2dc63 kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()
>
> actually regressed your 1024 CPU systems, and should possibly be reverted or fixed
> in some other fashion - such as by migrating to the primary CPU (on architectures
> that require that), instead of hotplug offlining every secondary CPU on every
> architecture!
>
> Alternatively, disable_nonboot_cpus() could perhaps be improved to down CPUs in
> parallel: issue the CPU-down requests to every CPU, then wait for them to complete
> - instead of the loop over every CPU?
>
> This would be the conceptual counter part to parallel boot up of CPUs - something
> SGI might be interested in as well?
>

Migrating to the boot processor and then calling stop_machine() to
defang any other processors should be sufficient, no?

I don't know if there is any reason to deschedule all tasks?

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.



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