On Fri, Aug 24, 2018 at 11:10:44AM -0500, Grygorii Strashko wrote:
> Yes. i do not see local_softirq_pending messages any more
> 
> But one question, just to clarify, after patch "nohz: Fix missing tick reprog 
> while interrupting inline timer softirq"
> the tick_nohz_irq_exit() will be called few times in case of nested 
> interrupts (min 2):
> gic_handle_irq
>  |- irq_exit
>     |- preempt_count_sub(HARDIRQ_OFFSET); 
>     |-__do_softirq 
>       <irqs enabled>
>       |- gic_handle_irq()
>          |- irq_exit()
>               |- tick_irq_exit()
>                  if (!in_irq())
>                       tick_nohz_irq_exit(); <-- [1]
>     |- tick_irq_exit()
>       if (!in_irq())
>               tick_nohz_irq_exit(); <-- [2]
> 
> Is it correct? in 4.14 tick_nohz_irq_exit() is much more complex then in LKML 
> now,
> and this is hot path.

That's correct and it's indeed more costly in 4.14 as then the tick is going to 
be programmed
twice.

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