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

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

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@arm.com>
>>> Cc: Frederic Weisbecker <frederic@kernel.org>
>>> Cc: Ingo Molnar <mingo@redhat.com>
>>> Cc: John Stultz <jstultz@google.com>
>>> Cc: Juri Lelli <juri.lelli@redhat.com>
>>> Cc: Peter Zijlstra <peterz@infradead.org>
>>> Cc: Thomas Gleixner <tglx@linutronix.de>
>>> Cc: Valentin Schneider <vschneid@redhat.com>
>>> Cc: Vincent Guittot <vincent.guittot@linaro.org>
>>> ---
>>>    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@linux.ibm.com>
> 
> Thanks!
> 
> Mark.