Re: [PATCH 01/32 RESEND] nohz: Drop useless call in tick_nohz_start_idle()

Frederic Weisbecker
2011-08-29T17:10:31Z

On Mon, Aug 29, 2011 at 04:23:10PM +0200, Peter Zijlstra wrote:
> On Mon, 2011-08-15 at 17:51 +0200, Frederic Weisbecker wrote:
> > The call to update_ts_time_stats() there is useless. All
> > we need is to save the idle entry_time.
> >
> >
> Would have been clearer if you just said the call was a NOP. The whole
> second sentence distracts and confuses as its irrelevant to the change
> at hand.
>
> If you want to expand you can explain that its a NOP because
> update_ts_time_stats() requires either ts->idle_active and/or
> @last_update_time and our callsite has neither.

Right, will fix the changelog.

>
> Although this assumes its never called when ts->idle_active is already
> set, is this so (likely)? Do we want a WARN_ON_ONCE() testing that
> assumption?

Not sure. Looking at the ondemand cpufreq governor, it calls
get_cpu_idle_time_us() from an initcall.