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Date: Fri, 8 Aug 2014 09:11:12 -0500 (CDT)
From: Christoph Lameter <cl@linux.com>
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To: Geert Uytterhoeven <geert@linux-m68k.org>
cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pekka Enberg <penberg@kernel.org>,
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        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Vladimir Davydov <vdavydov@parallels.com>
Subject: Re: BUG: enable_cpucache failed for radix_tree_node, error 12 (was:
 Re: [PATCH v3 9/9] slab: remove BAD_ALIEN_MAGIC)
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On Fri, 8 Aug 2014, Geert Uytterhoeven wrote:

> > Ok this is broken on m68k. CONFIG_NUMA is required for this to work. If
> > the arch code does this despite !CONFIG_NUMA then lots of things should
> > break.
>
> Can you please elaborate? We've been using for years...

!CONFIG_NUMA leads to the assumption of a system with a single node in
numerous places.

F.e. in include/linux/mm.h:


static inline int zone_to_nid(struct zone *zone)
{
#ifdef CONFIG_NUMA
        return zone->node;
#else
        return 0;
#endif
}