Re: [PATCH 0/2 v3] cpu hotplug: Preserve topology directory after soft remove event

From: Borislav Petkov
Date: Wed Sep 21 2016 - 09:04:40 EST


On Wed, Sep 21, 2016 at 07:39:31AM -0400, Prarit Bhargava wrote:
> The information in /sys/devices/system/cpu/cpuX/topology
> directory is useful for userspace monitoring applications and in-tree
> utilities like cpupower & turbostat.
>
> When down'ing a CPU the /sys/devices/system/cpu/cpuX/topology directory is
> removed during the CPU_DEAD hotplug callback in the kernel. The problem
> with this model is that the CPU has not been physically removed and the
> data in the topology directory is still valid. IOW, the cpu is still
> present but the kernel has removed the topology directory making it
> very difficult to determine exactly where the cpu is located.

So I'm afraid I still don't understand what the problem here is.

And the commit message of 2/2 doesn't make it any clearer. Can you
please give a concrete example what the problem is and what you're
trying to achieve.

Thanks.

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Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix ImendÃrffer, Jane Smithard, Graham Norton, HRB 21284 (AG NÃrnberg)
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