Re: nohz: Update tick instead of restarting tick in tick_nohz_idle_exit()

[Frederic Weisbecker]

On Mon, Nov 23, 2020 at 09:22:08PM +0800, Yunfeng Ye wrote:
> In realtime scenarios, the "nohz_full" parameter is configured. Tick
> interference is not expected when there is only one realtime thread.
> But when the idle thread is switched to the realtime thread, the tick
> timer is restarted always.
> 
> So on the nohz full mode, it is unnecessary to restart the tick timer
> when there is only one realtime thread. Adding can_stop_full_tick()
> before restarting the tick, if it return true, keep tick stopped.
> 
> Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>

We can indeed stop the tick and avoid it to be re-armed needlessly at this
point.

I'm taking your patch, I may just edit it a little and resend it.

Thanks!