Messages in this thread | | | Date | Sat, 6 Sep 2008 10:53:20 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] [RESEND] x86_64: add memory hotremove config option |
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On Sat, Sep 06, 2008 at 04:06:38PM +0900, Yasunori Goto wrote: > > not. > > > > This means I don't see a real use case for this feature. > > I don't think its driver is almighty. > IIRC, balloon driver can be cause of fragmentation for 24-7 system.
Sure the balloon driver can be likely improved too, it's just that I don't think a balloon driver should call into the function the original patch in the series hooked up. > > In addition, I have heard that memory hotplug would be useful for reducing > of power consumption of DIMM.
It's unclear that memory hotplug is the right model for DIMM power management. The problem is that DIMMs are interleaved, so you again have to completely free a quite large area. It's not much easier than node hotplug.
> I have to admit that memory hotplug has many issues, but I would like to
Let's call it "node" or "hardware" memory hot unplug, not that anyone confuses it with the easier VM based hot unplug or the really easy hotadd.
> solve them step by step.
The question is if they are even solvable in a useful way. I'm not sure it's that useful to start and then find out that it doesn't work anyways.
-Andi
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