On Wed, Dec 26, 2018 at 07:41:41PM -0800, Matthew Wilcox wrote:
>On Wed, Dec 26, 2018 at 09:14:47PM +0800, Fengguang Wu wrote:
>> From: Fan Du <fan.du@intel.com>
>>
>> This is a hack to enumerate PMEM as NUMA nodes.
>> It's necessary for current BIOS that don't yet fill ACPI HMAT table.
>>
>> WARNING: take care to backup. It is mutual exclusive with libnvdimm
>> subsystem and can destroy ndctl managed namespaces.
>
>Why depend on firmware to present this "correctly"?  It seems to me like
>less effort all around to have ndctl label some namespaces as being for
>this kind of use.

Dave Hansen may be more suitable to answer your question. He posted
patches to make PMEM NUMA node coexist with libnvdimm and ndctl:

[PATCH 0/9] Allow persistent memory to be used like normal RAM
https://lkml.org/lkml/2018/10/23/9

That depends on future BIOS. So we did this quick hack to test out
PMEM NUMA node for the existing BIOS.

Thanks,
Fengguang