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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH 04/11] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove
Cc: kosaki.motohiro@jp.fujitsu.com,
       Christoph Lameter <cl@linux-foundation.org>,
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Date: Fri, 19 Mar 2010 15:21:20 +0900 (JST)
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> On Thu, Mar 18, 2010 at 08:56:23AM +0900, KOSAKI Motohiro wrote:
> > > On Wed, 17 Mar 2010, Mel Gorman wrote:
> > > 
> > > > > If select MIGRATION works, we can remove "depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE"
> > > > > line from config MIGRATION.
> > > > >
> > > >
> > > > I'm not quite getting why this would be an advantage. COMPACTION
> > > > requires MIGRATION but conceivable both NUMA and HOTREMOVE can work
> > > > without it.
> > > 
> > > Avoids having to add additional CONFIG_XXX on the page migration "depends"
> > > line in the future.
> > 
> > Yes, Kconfig mess freqently shot ourself in past days. if we have a chance
> > to remove unnecessary dependency, we should do. that's my intention of the last mail.
> > 
> 
> But if the depends line is removed, it could be set without NUMA, memory
> hot-remove or compaction enabled. That wouldn't be very useful. I'm
> missing something obvious.

Perhaps I'm missing something. 

my point is, force enabling useless config is not good idea (yes, i agree). but config 
selectability doesn't cause any failure. IOW, usefulness and dependency aren't 
related so much. personally I dislike _unnecessary_ dependency.

If my opinion cause any bad thing, I'll withdraw it. of course.