From: Linus Torvalds
Sent: 19 September 2023 18:25
On Tue, 19 Sept 2023 at 06:48, John Paul Adrian Glaubitz
<glaubitz@xxxxxxxxxxxxxxxxxxx> wrote:
As Geert poined out, I'm not seeing anything particular problematic with the
architectures lacking CONFIG_PREEMPT at the moment. This seems to be more
something about organizing KConfig files.
It can definitely be problematic.
Not the Kconfig file part, and not the preempt count part itself.
But the fact that it has never been used and tested means that there
might be tons of "this architecture code knows it's not preemptible,
because this architecture doesn't support preemption".
Do distos even build x86 kernels with PREEMPT_FULL?
I know I've had issues with massive latencies caused graphics driver
forcing write-backs of all the framebuffer memory.
(I think it is a failed attempt to fix a temporary display corruption.)
OTOH SMP support and CONFIG_RT will test most of the code.
David
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