Re: [PATCH v2 08/13] mm/migrate_device: fix ksmd oops on a migrated KSM page

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Sat, Nov 14, 2026 at 11:56:57AM -0800, Chris Down wrote:
> Hi Lorenzo,
>
> Lorenzo Stoakes (ARM) writes:
> > [ ljs: tweak commit message, comment, also refuse device coherent ]
>
> Alistair's Reviewed-by on v1 came with the argument that KSM pages should
> still be able to go to device coherent memory [1], which is the opposite of
> what this does now, so it's probably worth checking that he's happy for it
> to be carried over. Going by what ksmd does with zone device pages, the
> change itself looks right to me.

Given the endless waves of AI fixes I think giving a little slack is fair
on details :)

But, yes, that was a mistake so - apologies Alistair, let me know if that's
OK.

>
> I've tested the device private case. Without this the process hangs the
> next time it touches one of the pages, and with it the migration is
> refused and the pages stay merged.
>
> [1] https://lore.kernel.org/r/avTu3LmscsttRVRp@nvdebian.thelocal
>
> Reviewed-by: Chris Down <chris@chrisdown.name>
> Tested-by: Chris Down <chris@chrisdown.name>

Thanks!

--
Cheers, Lorenzo