Re: [PATCH v1] liveupdate: separate memfd support into LIVEUPDATE_MEMFD

[Pratyush Yadav]

Hi Pasha,

On Tue, Dec 23 2025, Pasha Tatashin wrote:

> Decouple memfd preservation support from the core Live Update
> Orchestrator configuration.
>
> Previously, enabling CONFIG_LIVEUPDATE forced a dependency on
> CONFIG_SHMEM and unconditionally compiled memfd_luo.o. However, Live
> Update may be used for purposes that do not require memfd-backed memory
> preservation.

I initially didn't add a new config mainly because there was no other
user of LUO. So disabling LIVEUPDATE_MEMFD makes LUO entirely useless.

Anyway, we will eventually get other subsystems and this config will
start making sense then. Might as well do it now.

>
> Introduce CONFIG_LIVEUPDATE_MEMFD to gate memfd_luo.o. This moves the
> SHMEM and MEMFD_CREATE dependencies to the specific feature that needs
> them, allowing the base LIVEUPDATE option to be selected independently
> of shared memory support.
>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
> ---
>  kernel/liveupdate/Kconfig | 16 +++++++++++++++-
>  mm/Makefile               |  2 +-

I think you should also update tools/testing/selftests/liveupdate/config
to enable this config.

With that,

Reviewed-by: Pratyush Yadav <pratyush@xxxxxxxxxx>

>  2 files changed, 16 insertions(+), 2 deletions(-)
>
[...]

-- 
Regards,
Pratyush Yadav