Re: [PATCH 1/5] sched: dynamic: Make PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY

[Mark Rutland <mark.rutland@arm.com>]

On Mon, Jul 06, 2026 at 10:06:29AM +0530, Shrikanth Hegde wrote:
> On 7/3/26 7:03 PM, Mark Rutland wrote:
> > On architectures which select ARCH_HAS_PREEMPT_LAZY, it has not been
> > possible to select the NONE and VOLUNTARY preemption models since
> > commit:
> > 
> >    7dadeaa6e851 ("sched: Further restrict the preemption modes")
> > 
> > ... which was merged in v7.0.
> > 
> > All architectures which currently suppoort PREEMPT_DYNAMIC select
> 
> s/suppoort/support

Thanks; fixed locally now.

[...]

> > diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
> > index 88c594c6d7fcd..fb49424003b2b 100644
> > --- a/kernel/Kconfig.preempt
> > +++ b/kernel/Kconfig.preempt
> > @@ -129,6 +129,7 @@ config PREEMPTION
> >   config PREEMPT_DYNAMIC
> >   	bool "Preemption behaviour defined on boot"
> >   	depends on HAVE_PREEMPT_DYNAMIC
> > +	depends on ARCH_HAS_PREEMPT_LAZY
> >   	select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY
> >   	select PREEMPT_BUILD
> >   	default y if HAVE_PREEMPT_DYNAMIC_CALL
> 
> 
> Can we update the help section bit?
> 
> """
>           The runtime overhead is negligible.
> 
>           Interesting if you want the same pre-built kernel should be used for
>           both Server and Desktop workloads.
> """
> I think server meant preempt=none and desktop meant preempt=full/lazy there. No?

I think that's the common case, yes.

I think the existing wording isn't wrong, so I'm going to leave it as-is
for now, given the wording change is logically separate from the other
changes.

[...]

> other than that, it looks good to me.
> 
> Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>

Thanks!

Mark.