Re: [RESEND PATCH v10] x86, apic, kexec, Documentation: Add disable_cpu_apicidkernel parameter

From: H. Peter Anvin
Date: Wed Jan 15 2014 - 12:27:38 EST


On 01/15/2014 09:05 AM, Vivek Goyal wrote:
>
> I think this is a reasonable approach to solve the issue. Use a command
> line to not bring up specific cpu in second kernel which can create
> problems.
>
> Acked-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
>
> hpa, I know you are not excited about this approach. If you made up your
> mind that this appoarch is not worth pursuing, please do suggest what
> would you like to see and we can give that a try.
>
> We want to solve this problem as on large memory machines saving dump can
> take lot of time and we want to bring up multiple cpus and speed up
> compression and save on dump time.
>

I'm not excited about kdump's reliance on the command line, since it
seems to be a neverending source of trouble, simply because the command
line is fundamentally intended as a human interface. However, this
seems relatively harmless in comparison with everything else and I am
much happier with saving the ID in the first kernel rather than trying
to guess if a currently-downed CPU is the BSP.

-hpa

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