Re: [RFC][PATCH v2 01/21] e820: cheat PMEM as DRAM
From: Dan Williams
Date: Thu Dec 27 2018 - 00:15:30 EST
On Wed, Dec 26, 2018 at 8:11 PM Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
> 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@xxxxxxxxx>
> >> 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
> That depends on future BIOS. So we did this quick hack to test out
> PMEM NUMA node for the existing BIOS.
No, it does not depend on a future BIOS.
Willy, have a look here , here , and here  for the
work-in-progress ndctl takeover approach (actually 'daxctl' in this