Re: [PATCH] mm, x86: Skip NUMA_NO_NODE while parsing SLIT

Yasuaki Ishimatsu
2013-12-06T07:24:29Z

(2013/12/06 0:11), Toshi Kani wrote:
> On Thu, 2013-12-05 at 19:25 +0900, Yasuaki Ishimatsu wrote:
>> (2013/12/05 6:09), Toshi Kani wrote:
>>> When ACPI SLIT table has an I/O locality (i.e. a locality unique
>>> to an I/O device), numa_set_distance() emits the warning message
>>> below.
>>>
>>> NUMA: Warning: node ids are out of bound, from=-1 to=-1 distance=10
>>>
>>> acpi_numa_slit_init() calls numa_set_distance() with pxm_to_node(),
>>> which assumes that all localities have been parsed with SRAT previously.
>>> SRAT does not list I/O localities, where as SLIT lists all localities
>>
>>> including I/Os. Hence, pxm_to_node() returns NUMA_NO_NODE (-1) for
>>> an I/O locality. I/O localities are not supported and are ignored
>>> today, but emitting such warning message leads unnecessary confusion.
>>
>> In this case, the warning message should not be shown. But if SLIT table
>> is really broken, the message should be shown. Your patch seems to not care
>> for second case.
>
> In the second case, I assume you are worrying about the case of SLIT
> table with bad locality numbers. Since SLIT is a matrix of the number
> of localities, it is only possible by making the table bigger than
> necessary. Such excessive localities are safe to ignore (as they are
> ignored today) and regular users have nothing to concern about them.
> The warning message in this case may be helpful for platform vendors to
> test their firmware, but they have plenty of other methods to verify
> their SLIT table.

I understood it. So,

Reviewed-by : Yasuaki Ishimatsu

Thanks,
Yasuaki Ishimatsu

> Thanks,
> -Toshi
>
>
>
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