On Mon, Feb 01, 2016 at 02:21:46PM +0530, Anshuman Khandual wrote:
> On 01/29/2016 10:54 AM, David Gibson wrote:
> > #ifdef CONFIG_MEMORY_HOTPLUG
> > +void resize_hpt_for_hotplug(unsigned long new_mem_size)
> > +{
> > + unsigned target_hpt_shift;
> > +
> > + if (!ppc_md.resize_hpt)
> > + return;
> > +
> > + target_hpt_shift = htab_shift_for_mem_size(new_mem_size);
> > +
> > + /*
> > + * To avoid lots of HPT resizes if memory size is fluctuating
> > + * across a boundary, we deliberately have some hysterisis
>
>
> What do you mean by 'memory size is fluctuating across a boundary' ?
> Through memory hotplug interface ? Why some one will do that ?I was thinking it might be possible to have some management system that automatically adjusts memory size based on load, and if that happened to land on a boundary you could get nasty behaviour. > I > can understand why we dont have this check in the sysfs debug path > as we would like to test any memory HPT re sizing scenario we want > in any sequence of increase or decrease we want. > > Overall the RFC V2 looks pretty good. Looking forward to see the > host side of the code for this feature. The qemu host side has been posted to [email protected] already. I haven't started on a KVM HV implementation yet. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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