Re: [patch 09/14] x86_64: Don't call enforce_max_cpus when hotplug is enabled

[Andi Kleen]

On Tue, Sep 06, 2005 at 03:56:17PM -0700, Ashok Raj wrote:
> Hi Andi
> 
> On Mon, Sep 05, 2005 at 06:48:21AM +0200, Andi Kleen wrote:
> > On Sat, Sep 03, 2005 at 02:33:26PM -0700, akpm@xxxxxxxx wrote:
> > > 
> > > From: Ashok Raj <ashok.raj@xxxxxxxxx>
> > > 
> > > No need to enforce_max_cpus when hotplug code is enabled.  This nukes out
> > > cpu_present_map and cpu_possible_map making it impossible to add new cpus in
> > > the system.
> > 
> > I see the point, but the implementation is wrong. If anything
> > we shouldn't do it neither for the !HOTPLUG_CPU case.Why did 
> > you not do it unconditionally? 
> > 
> > I would prefer to keep the special cases for hotplug to be
> > as narrow as possible.
> 
> Link to earlier discussion below
> 
> http://marc.theaimsgroup.com/?l=linux-kernel&m=112317327529855&w=2
> 
> I had suggested that we remove it completely in our discussion but i didnt
> hear anything from you after that, so i thought that was acceptable.

Just because I don't follow up on everything doesn't necessarily
mean the patch is acceptable.

> 
> You had suggested in that discussion that it would be better to add an 
> option for startup. Iam opposed to adding any option, when we certainly know 

I suggested to auto detect it based on ACPI information. I don't 
think I ever wrote anything about an option.

If that is not possible it's better to always use the sequence mechanism.

> there are no users. Earlier based on your suggestion i added a startup
> option to choose ipi broadcast mode, which you promptly removed when you
> put physflat changes. I think its better to not add any option without
> real need. Do you agree?

Yes. 

> Please reply if you want me to remove the !HOTPLUG case which is my 
> preference as well, and maybe while the memory is fresh, we can stick
> with it this time when we are in the same page :-(

Yes, as I wrote earlier hotplug should be removed.

-Andi

P.S.: Don't bother sending me such "blame game" mails again. I will
just d them next time because they're a waste of time.

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