Re: [PATCH] cpufreq: schedutil: Skip busy-CPU hold when NOHZ is disabled

[Zhongqiu Han]

On 11/3/2026 3:17 PM, Zhan Xusheng wrote:
> Hi Avi,
>
> On Tue, Nov 03, 2026 at 08:15:57AM +0200, Avi Weiss wrote:
> > +	if (!tick_nohz_enabled)
> > +		return false;
>
> idle_calls also never moves when nohz is enabled but was never
> activated, because tick_check_oneshot_change() found no oneshot clock
> event device or no clocksource valid for high resolution. TS_FLAG_NOHZ
> then stays clear, as with nohz=off. tick_nohz_is_active() covers both:
>
> 	if (!tick_nohz_is_active())
> 		return false;

Agree with Xusheng, tick_nohz_is_active() is one more reasonable check,
it also covers NOHZ never getting activated. Besides please Cc: stable,
and Cc the scheduler maintainers (scripts/get_maintainer.pl).

Note that this still leaves the nohz_full timekeeping CPU and idle=poll,
where NOHZ is active but idle_calls never moves either. That's a deeper
issue with using a tick-stop counter as an "idle recently" signal and
it may be addressed separately.

> Thanks,
> Zhan Xusheng


--
Thx and BRs,
Zhongqiu Han