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Date:   Wed, 9 Oct 2019 13:04:12 +0100
From:   Matt Fleming <matt@codeblueprint.co.uk>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
        Rik van Riel <riel@surriel.com>,
        Suravee.Suthikulpanit@amd.com, Borislav Petkov <bp@alien8.de>,
        Thomas.Lendacky@amd.com, Mel Gorman <mgorman@techsingularity.net>,
        Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH v4 2/2] sched/topology: Improve load balancing on AMD EPYC
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 <20191007152816.GA10940@roeck-us.net>
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On Mon, 07 Oct, at 08:28:16AM, Guenter Roeck wrote:
> 
> This patch causes build errors on systems where NUMA does not depend on SMP,
> for example MIPS and PPC. For example, building mips:ip27_defconfig with SMP
> disabled results in
> 
> mips-linux-ld: mm/page_alloc.o: in function `get_page_from_freelist':
> page_alloc.c:(.text+0x5018): undefined reference to `node_reclaim_distance'
> mips-linux-ld: page_alloc.c:(.text+0x5020): undefined reference to `node_reclaim_distance'
> mips-linux-ld: page_alloc.c:(.text+0x5028): undefined reference to `node_reclaim_distance'
> mips-linux-ld: page_alloc.c:(.text+0x5040): undefined reference to `node_reclaim_distance'
> Makefile:1074: recipe for target 'vmlinux' failed
> make: *** [vmlinux] Error 1
> 
> I have seen a similar problem with one of my PPC test builds.
> 
> powerpc64-linux-ld: mm/page_alloc.o:(.toc+0x18): undefined reference to `node_reclaim_distance'

Thanks for this Guenter.

So, the way I've fixed this same issue for ia64 was to make NUMA
depend on SMP. Does that seem like a suitable solution for both PPC
and MIPS?