Re: [PATCH] mm: add config NUMA stub to all architectures

From: Randy Dunlap
Date: Sun Feb 19 2012 - 13:13:06 EST


On 02/19/2012 09:01 AM, Geert Uytterhoeven wrote:
On Fri, Feb 17, 2012 at 21:30, Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
On Fri, 17 Feb 2012 16:08:15 +0400
Konstantin Khlebnikov<khlebnikov@xxxxxxxxxx> wrote:

Config NUMA must be defined for all architectures,
otherwise IS_ENABLED(CONFIG_NUMA) does not work.
Some arch-specific Kconfig already has this stub.
This patch adds it to all remaining.

It would be better to teach IS_ENABLED() to handle this situation. I
don't think there's a way of doing this with cpp :(

This limitation makes IS_ENABLED pretty dangerous, doesn't it? It
makes it very easy to introduce build breakage with unexpected Kconfig
combinations.

Indeed. Recently I discovered IS_ENABLED() and started recommending it
to people for new code. But now I've seen the CONFIG_NUMA breakage,
I no longer think this is a good recommendation.


adding Michal & linux-kbuild to cc: list.

--
~Randy
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