Messages in this thread | | | Subject | Re: [PATCH v2 0/2] new cpumask for hotpluggable CPUs | From | Peter Zijlstra <> | Date | Thu, 11 Aug 2011 20:30:23 +0200 |
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On Wed, 2011-08-10 at 13:03 -0700, Mike Turquette wrote: > This patch series introduces a new cpumask which tracks CPUs that > support hotplugging. The purpose of this patch series is to provide a > simple method for kernel code to know which CPUs can be hotplugged and > which ones cannot. Potential users of this code might be a thermal > mitigation technique which uses hotplug to lower temperature, or a power > capping mechanism which uses hotplug to lower power consumption. > > All the of usual cpumask helper functions are created for this new mask. > The second patch in this series simply sets the bit for elligible CPUs > while they are being registered. The cpumask itself is static after > boot and should not change (like the possbile mask).
I still most strongly object to people using hotplug for these goals.
Why do you need to go through the entire dance of hotplug just to idle a cpu? Hotplug not only idles the cpu but tears down (and rebuilds) an insane amount of resources associated with the cpu.
Nacked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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