Re: [PATCH 4/5] sched: dynamic: Simplify irqentry_exit_cond_resched()

[Christophe Leroy (CS GROUP)]

Hi Mark,

Le 17/07/2026 à 13:05, Mark Rutland a écrit :
> On Mon, Jul 06, 2026 at 10:12:29AM +0530, Shrikanth Hegde wrote:
> > +cc Christophe.
> >
> > On 7/3/26 7:03 PM, Mark Rutland wrote:
> > > PREEMPT_DYNAMIC is now limited to the FULL and LAZY preemption models.
> > > In either model, irqentry_exit_cond_resched() is always called and never
> > > disabled.
> > >
> > > Remove the unnecessary code for this when PREEMPT_DYNAMIC is selected.
> > >
> > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
> > > Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
> > > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > > Cc: John Stultz <jstultz@xxxxxxxxxx>
> > > Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
> > > Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> > > ---
> > >    arch/powerpc/include/asm/preempt.h |  7 -------
> > >    include/linux/irq-entry-common.h   | 17 +----------------
> > >    kernel/entry/common.c              | 17 ++---------------
> > >    kernel/sched/core.c                |  7 -------
> > >    4 files changed, 3 insertions(+), 45 deletions(-)
> > >
> > > diff --git a/arch/powerpc/include/asm/preempt.h b/arch/powerpc/include/asm/preempt.h
> > > index 000e2b9681f30..79fc1f9df88d9 100644
> > > --- a/arch/powerpc/include/asm/preempt.h
> > > +++ b/arch/powerpc/include/asm/preempt.h
> > > @@ -4,13 +4,6 @@
> > >    #include <asm-generic/preempt.h>
> > > -#if defined(CONFIG_PREEMPT_DYNAMIC)
> > > -#include <linux/jump_label.h>
> > > -DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
> > > -#define need_irq_preemption() \
> > > -	(static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
> > > -#else
> > >    #define need_irq_preemption()   (IS_ENABLED(CONFIG_PREEMPTION))
> > > -#endif
> >
> > JFYI,
> > Christophe had sent this patch, I am sure you guys will sort out the
> > conflicts. (I don't see it merged yet, but likely might)
> >
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F2bf10a0afffefb6aca44bf2f864cc17471a80e31.1781870889.git.chleroy%40kernel.org%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cd53a0ccd869f471aaafe08dee3f345aa%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639198831155344265%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=Uz61UVryN4sw1GprTddsVCFvEkuXguHZufVNJr0PpeY%3D&reserved=0
>
> Thanks for the heads-up!
>
> Sorry, I'd skipped Ccing all the arch folk as I hadn't expected anyone
> was likely to be doing similar in the arch code right now. I'll make
> sure you're both Cc'd for any subsequent versions.
>
> It looks like the only difference for powerpc is that I leave
> need_irq_preemption() lying around. Christophe, if you're happy with
> this series, I could pick a patch from you to remove that (e.g. take
> your patch and apply it to the end of this series, reduced to removing
> need_irq_preemption()).
>
> Any preference?

I'm just back from summer vacation.

No preference, but it looks like my patch was merged into v7.2-rc4 as 
commit a2c02aa0c6ca ("powerpc: Remove dead non-preemption code"), so I 
fear you'll need to rebase your work on top of it.

Christophe

> [...]
>
> > Change per se, looks good to me.
> >
> > Reviewed-by: Shrikanth Hegde <sshegde@xxxxxxxxxxxxx>
>
> Thanks!
>
> Mark.