Re: [PATCH] hw/arm: add static NVDIMMs in device tree

[David Hildenbrand <david@redhat.com>]

On 20.08.25 06:10, Gao Xiang wrote:
> (try to Cc David and Paolo for some discussion...)
> 
> Hi David and Paolo,
> 

Hi!

> If possible, could you share some thoughts about this, because
> currently each `memory-backend-file` has their own page cache
> on the host, but if QEMU can provide one nvdimm device backed
> by multiple files, so that EROFS can share memory in finer
> layer granularity on the host.  (we don't need to attach so
> many devices, because some container images can be dozens of
> layers.)

Sounds a bit like what virtio-fs does?

> 
> Without further investigatation, I wonder which direction is
> better:
> 
>     1) one memory-backend-file backed by multiple files;

No.

> 
>     2) nvdimm, virtio-pmem, .. backed by multiple
>        `memory-backend-file`s..

Better.

> 
> Currently I don't have extra slot to look into the QEMU codebase,
> but if the idea is acceptable, I will try to work on this later.

But is this really better than just using many devices?

-- 
Cheers

David / dhildenb