Re: [PATCH] Dynamic tick for x86 version 050602-2

[Tony Lindgren]

* Pavel Machek <pavel@xxxxxx> [050610 02:15]:
> Hi!
> 
> > > > +#define NS_TICK_LEN		((1 * 1000000000)/HZ)
> > > > +#define DYN_TICK_MIN_SKIP	2
> > > > +
> > > > +#ifdef CONFIG_NO_IDLE_HZ
> > > > +
> > > > +extern unsigned long dyn_tick_reprogram_timer(void);
> > > > +
> > > > +#else
> > > > +
> > > > +#define arch_has_safe_halt()		0
> > > > +#define dyn_tick_reprogram_timer()	{}
> > > 
> > > do {} while (0)
> > > 
> > > , else you are preparing trap for someone.
> > 
> > Can you please explain what the difference between these two are?
> > Some compiler version specific thing?
> 
> It took me quite some remembering. Problem is that with your macros,
> someone can write
> 
> 	dyn_tick_reprogram_timer()
> 	printk();
> 
> [notice missing ; at first line], and still get it compile. If you
> replace {} with do {} while (0), he'll get compile error as he should.

Thanks for clarifying, I'll change it.

Tony
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