Re: [PATCH v8 0/5] Migrate on fault for device pages

[Mika Penttilä]

On 4/24/26 19:23, Andrew Morton wrote:

> On Tue, 14 Apr 2026 07:12:21 +0300 mpenttil@xxxxxxxxxx wrote:
>
>> From: Mika Penttilä <mpenttil@xxxxxxxxxx>
>>
>> Currently, the way device page faulting and migration works
>> is not optimal, if you want to do both fault handling and
>> migration at once.
>>
>> Being able to migrate not present pages (or pages mapped with incorrect
>> permissions, eg. COW) to the GPU requires doing either of the
>> following sequences:
>>
>> ...
>>
> Via which tree would it be best to upstream this?
>
>>  include/linux/hmm.h                    |  19 +-
>>  include/linux/migrate.h                |  26 +-
>>  lib/test_hmm.c                         | 101 ++-
>>  lib/test_hmm_uapi.h                    |  19 +-
>>  mm/Kconfig                             |   2 +
>>  mm/hmm.c                               | 821 +++++++++++++++++++++++--
>>  mm/migrate_device.c                    | 589 +++---------------
>>  tools/testing/selftests/mm/hmm-tests.c |  54 ++
>>  8 files changed, 1053 insertions(+), 578 deletions(-)
> Looks like mm.git.
>
> It might be more useful to add it to a DRM tree if there's ongoing
> development against this.  But please no upstreaming without good
> review!
>
> Anyway, this is a bit dated and Sashiko AI review wasn't able to apply
> the patches.  Nor was it able to apply v7 or v6.  So please refresh,
> retest, resend?

It is against Linus tree v7.0, base-commit: 028ef9c96e96197026887c0f092424679298aae8,
but applies and passes hmm selftests on mm trees as is.

I plan to do v9 refresh and maybe minor updates in week or so.

--Mika