[PATCH v2 00/19] mm: Support huge pfnmaps

[Jiaqi Yan]

On Wed, Aug 28, 2024 at 7:24 AM Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> On Tue, Aug 27, 2024 at 05:42:21PM -0700, Jiaqi Yan wrote:
>
> > Instead of removing the whole pud, can driver or memory_failure do
> > something similar to non-struct-page-version of split_huge_page? So
> > driver doesn't need to re-fault good pages back?
>
> It would be far nicer if we didn't have to poke a hole in a 1G mapping
> just for memory failure reporting.

If I follow this, which of the following sounds better? 1. remove pud
and rely on the driver to re-fault PFNs that it knows are not poisoned
(what Peter suggested), or 2. keep the pud and allow access to both
good and bad PFNs.

Or provide some knob (configured by ?) so that kernel + driver can
switch between the two?

>
> Jason