Re: [PATCH 2.6.21 review I] [11/25] x86: default to physical mode on hotplug CPU kernels

[Siddha, Suresh B]

On Mon, Feb 12, 2007 at 11:36:23PM +0100, Andi Kleen wrote:
> True, that seems to be missing.
> 
> I agree that the patch seems to consist mostly of renaming doesn't make
> it any easier to read.
> 
> And it's worrying that it doesn't handle the hotplug case at all.

This patch is mostly a cleanup patch and doesn't have to do anything with
hotplug. I think the change log comment about hotplug kernel is a leftover
from an old patch.

> But I'm tempted to drop this unless the hotplug mystery can be cleared
> up. There was past information that logical is unsafe for hotplug.
> 
> Ingo? Suresh? 

logical clustered mode has problems with cpu hotplug.
( http://marc.theaimsgroup.com/?l=linux-kernel&m=113261865814107&w=2 )

I think logical flat is fine. We should be fine in logical flat, as long as
we are not using apic IPI shortcuts.

thanks,
suresh
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