Re: [pchecks v1 2/4] Use raw cpu ops for calls that would triggerwith checks

From: Ingo Molnar
Date: Tue Sep 24 2013 - 03:35:05 EST



* Christoph Lameter <cl@xxxxxxxxx> wrote:

> Index: linux/kernel/hrtimer.c
> ===================================================================
> --- linux.orig/kernel/hrtimer.c 2013-09-12 13:26:29.216103951 -0500
> +++ linux/kernel/hrtimer.c 2013-09-12 13:26:29.212103994 -0500
> @@ -538,7 +538,7 @@ static inline int hrtimer_is_hres_enable
> */
> static inline int hrtimer_hres_active(void)
> {
> - return __this_cpu_read(hrtimer_bases.hres_active);
> + return raw_cpu_read(hrtimer_bases.hres_active);
> }

If cpu_read() is used, does this check trigger?

If yes, what makes ignoring the check safe? Per change explanation is
necessary for such annotations.

Thanks,

Ingo
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