Re: [PATCH RFC 10/10] nvdimm/e820: add multiple namespaces support

[Dan Williams]

On Tue, Feb 4, 2020 at 7:30 AM Barret Rhoden <brho@xxxxxxxxxx> wrote:
>
> Hi -
>
> On 1/10/20 2:03 PM, Joao Martins wrote:
> > User can define regions with 'memmap=size!offset' which in turn
> > creates PMEM legacy devices. But because it is a label-less
> > NVDIMM device we only have one namespace for the whole device.
> >
> > Add support for multiple namespaces by adding ndctl control
> > support, and exposing a minimal set of features:
> > (ND_CMD_GET_CONFIG_SIZE, ND_CMD_GET_CONFIG_DATA,
> > ND_CMD_SET_CONFIG_DATA) alongside NDD_ALIASING because we can
> > store labels.
>
> FWIW, I like this a lot.  If we move away from using memmap in favor of
> efi_fake_mem, ideally we'd have the same support for full-fledged
> pmem/dax regions and namespaces that this patch brings.

No, efi_fake_mem only supports creating dax-regions. What's the use
case that can't be satisfied by just specifying multiple memmap=
ranges?