Re: [ANNOUNCE] v5.14-rc4-rt4

[Sebastian Andrzej Siewior]

On 2021-08-04 10:57:11 [-0600], Jens Axboe wrote:
> > The spin_lock_irq() vs local_irq_disable() + spin_lock() is documented
> > in Documentation/locking/locktypes.rst.
> > That said I have no problem by carrying that patch in the RT-patchset
> > and revisit it later.
> 
> Right, I suspect that was added as a pre RT patch dump at some point.
> It's a newer thing. Is it actually possible to set PREEMPT_RT in the
> mainline kernel? Looks like it depends on ARCH_SUPPORTS_RT and nobody
> sets that.

Yes. It is upstream now. The documentation and CONFIG_PREEMPT_RT symbol.
The Kconfig symbol has already users outside of the -RT patch.

You can't enable it yet since we require a few things which are on their
way.

Having the symbol and the documentation helped to convince some people
:) 

> So I agree that just carrying your solution in the RT patchset is fine
> for now, we can revisit later.

Okay.

Sebastian