Re: [PATCH v5 21/23] rv: Add rtapp_sleep monitor

[Nam Cao <namcao@linutronix.de>]

On Wed, Apr 30, 2025 at 10:05:07AM +0200, Gabriele Monaco wrote:
> I've got one more small remark though, the name ALLOWLIST doesn't give
> justice to what you explained above.
> It suggests me something potentially wrong that we can't do much about,
> while in case of RT mutexes and futex lock, we just don't want the
> monitor to yell in a perfectly RT-compliant scenario.
> 
> What is happening here, from what I see, is that the kernel is handling
> the RT behaviour and your monitor is just meant to tell when userspace
> is doing something it could do better (unless we deal with kthreads,
> there we are in fact whitelisting the ones we know are not complying).
> 
> What about calling it RT_KERNEL_MANAGED_SLEEP or something along the
> line to say we just trust what the kernel is doing?

That would also work. The generated automaton should be exactly the same.

But I think this is quite subjective, so let's not argue too much about it.
In short, I prefer it as is, sorry.

I think "ALLOWLIST" is a suitable name. From Wikipedia: "A whitelist or
allowlist is a list or register of entities that are being provided a
particular privilege, service, mobility, access or recognition. Entities on
the list will be accepted, approved and/or recognized".

We trust rt_mutex and futex_lock_pi to do the right things, so I think they
belong to the allowlist. We also trust the RCU thread and the migration/
threads to be correct.

Best regards,
Nam