Re: [PATCH, RFC 2/2] Implement sharing/unsharing of PMDs for FS/DAX

From: Kirill A. Shutemov
Date: Tue Jun 11 2019 - 22:12:25 EST

On Fri, May 24, 2019 at 09:07:11AM -0700, Larry Bassel wrote:
> Again, I don't think this can happen in DAX. The only sharing allowed
> is for FS/DAX/2MiB pagesize.

Hm. I still don't follow. How do you guarantee that DAX actually allocated
continues space for the file on backing storage and you can map it with
PMD page? I believe you don't have such guarantee.

Kirill A. Shutemov