Re: Arches that don't support PREEMPT

[Anton Ivanov]

On 19/09/2023 16:17, Thomas Gleixner wrote:
> On Tue, Sep 19 2023 at 15:21, Anton Ivanov wrote:
> > On 19/09/2023 14:42, Peter Zijlstra wrote:
> > > If you're working on one of them, then surely it's a simple matter of
> > > working on adding CONFIG_PREEMPT support :-)
> > In the case of UML adding preempt will be quite difficult. I looked at
> > this a few years back.
> What's so difficult about it?

It's been a while. I remember that I dropped it at the time, but do not remember the full details.

There was some stuff related to FP state and a few other issues I ran into while rewriting the interrupt controller. Some of it may be resolved by now as we are using host cpu flags, etc.

I can give it another go :)

> Thanks,
>
>          tglx
--
Anton R. Ivanov
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