Re: [PATCH] arm64: Avoid pointless schedule_preempt_irq() invocations

[Thomas Gleixner]

On Wed, 17 Jul 2019, Valentin Schneider wrote:

> On 17/07/2019 09:43, Thomas Gleixner wrote:
> > When preempt_count is zero on return from interrupt then
> > schedule_preempt_irq() is invoked even if TIF_NEED_RESCHED is not set.
> > 
> > That does not make sense because schedule_preempt_irq() has to go through a
> > full __schedule() for nothing in that case.
> > 
> > Check TIF_NEED_RESCHED and invoke schedule_preempt_irq() only if set.
> > 
> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> 
> Don't we have NEED_RESCHED squashed into preempt count?
> 
>   396244692232 ("arm64: preempt: Provide our own implementation of asm/preempt.h")
> 
> So the existing check should cover that, unless I'm missing something?

Right. Ignore me.