Re: [patch 3/3] tick: Annotate tick_do_timer_cpu data races

From: Paul E. McKenney
Date: Tue Dec 08 2020 - 10:04:16 EST


On Tue, Dec 08, 2020 at 09:11:29AM +0100, Peter Zijlstra wrote:
> On Mon, Dec 07, 2020 at 11:44:06AM -0800, Paul E. McKenney wrote:
>
> > Also, in this particular case, why data_race() rather than READ_ONCE()?
> > Do we really expect the compiler to be able to optimize this case
> > significantly without READ_ONCE()?
>
> It's about intent and how the code reads. READ_ONCE() is something
> completely different from data_race(). data_race() is correct here.

Why?

Thanx, Paul