Re: [PATCH 04/11] Allow CONFIG_MIGRATION to be set without CONFIG_NUMA or memory hot-remove

[KOSAKI Motohiro]

> On Fri, Mar 19, 2010 at 03:21:20PM +0900, KOSAKI Motohiro wrote:
> > > 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.
> > 
> 
> I've changed the MIGRATION entry to
> 
> config MIGRATION
>         bool "Page migration"
>         def_bool y
>         depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE 
> 
> i.e. it no longer depends on COMPACTION because the "select MIGRATION"
> in that line is enough.
> 
> I've left NUMA and HOTREMOVE because migration is an optional feature
> for those configurations.

ok... I don't oppose it anymore. Let's dive into Kconfig select hell ;)


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