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

[Pasha Tatashin]

On Mon, Dec 29, 2025 at 3:52 PM Pratyush Yadav <pratyush@xxxxxxxxxx> wrote:
>
> 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.

Done

>
> With that,
>
> Reviewed-by: Pratyush Yadav <pratyush@xxxxxxxxxx>

Thanks.

Pasha