Re: [PATCH v4] efivarfs: add nostatfs mount option to skip QueryVariableInfo()

[Sebastian Andrzej Siewior]

On 2026-09-29 18:35:00 [-0700], Prashant Singh wrote:
> >could this be, I don't know something smaller not including the
> >commandline where I would expect that people know how to use it.
> >
> >===================     =========================================================
> >(no)statfs              Control whether ``statfs(2)`` reports the variable-store
> >                        used/ available. Disabling it skips the EFI runtime
> >                        service call, which might block the CPU for a few milliseconds,
> >                        reporting 0 for used and capacity. Enabled by default on
> >                        PREEMPT_RT.
> >===================     =========================================================
> >
> >It might make sense to add this knob to Documentation/core-api/real-time/hardware.rst.
> 
> Thanks, I will use this wording and move it to
> Documentation/core-api/real-time/hardware.rst.

Please keep this description _here_ where you have it. Once this is
merged, you could send another patch, extending the documentation with
the statfs option (I think the workqueue change is in).

You still have the problem that someone reading the variable leads to
the same program but this requires a privileged user. And if I am not
mistaken, someone sent patches to have efi-runtime runtime disabled/
enabled.

> Thanks,
> Prashant

Sebastian