Re: clocksource_watchdog causing scheduling of timers every second (was [v13] support "task_isolation" mode)

[Christoph Lameter]

On Wed, 27 Jul 2016, Chris Metcalf wrote:

> > Should we just cycle through the cpus that are not isolated? Otherwise we
> > need to have some means to check the clocksources for accuracy remotely
> > (probably impossible for TSC etc).
>
> That sounds like the right idea - use the housekeeping cpu mask instead of the
> cpu online mask.  Should be a straightforward patch; do you want to do that
> and test it in your configuration, and I'll include it in the next spin of the
> patch series?

Sadly housekeeping_mask is defined the following way:

static inline const struct cpumask *housekeeping_cpumask(void)
{
#ifdef CONFIG_NO_HZ_FULL
        if (tick_nohz_full_enabled())
                return housekeeping_mask;
#endif
        return cpu_possible_mask;
}

Why is it not returning cpu_online_mask?