Re: [PATCH 01/15] sched/idle: Handle offlining first in idle loop

[Frederic Weisbecker <frederic@kernel.org>]

Le Mon, Jan 19, 2026 at 01:53:47PM +0100, Peter Zijlstra a écrit :
> On Fri, Jan 16, 2026 at 03:51:54PM +0100, Frederic Weisbecker wrote:
> 
> >  kernel/sched/idle.c | 11 ++++++-----
> >  1 file changed, 6 insertions(+), 5 deletions(-)
> > 
> > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
> > index c174afe1dd17..35d79af3286d 100644
> > --- a/kernel/sched/idle.c
> > +++ b/kernel/sched/idle.c
> > @@ -260,6 +260,12 @@ static void do_idle(void)
> >  {
> >  	int cpu = smp_processor_id();
> >  
> > +	if (cpu_is_offline(cpu)) {
> 
> Does it make sense to make that: if (unlikely(cpu_is_offline(cpu))) ?

Yes indeed!

> 
> > +		local_irq_disable();
> 
> Also, do we want something like:
> 
> 		WARN_ON_ONCE(need_resched());
> 
> ?

Definetly.

Thanks.

-- 
Frederic Weisbecker
SUSE Labs