[Y_Y]

> This approach can work, see for instance the history of PREEMPT-RT.

Good point, I note that realtime preemption has been in the works for more than twenty years, but (surprisingly) still isn't in mainline. On the other hand it's widely used and available and has caused lots of changes upstream already.

https://lwn.net/Articles/951337/

[deng]

PREEMPT-RT is almost completely in mainline. As your linked article says, pretty much the last issue is printk. You can download the last patch here, it's not much anymore:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.11/

And this is the only way you'll get large changes like these into the kernel: slow and steady.