Re: [RFT][PATCH v4 1/7] time: tick-sched: Reorganize idle tick management code

From: Rafael J. Wysocki
Date: Thu Mar 15 2018 - 08:33:26 EST


On Wednesday, March 14, 2018 4:49:39 PM CET Frederic Weisbecker wrote:
> On Mon, Mar 12, 2018 at 10:47:41AM +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Prepare the scheduler tick code for reworking the idle loop to
> > avoid stopping the tick in some cases.
> >
> > Move away the tick_nohz_start_idle() invocation from
> > __tick_nohz_idle_enter(), rename the latter to
> > __tick_nohz_idle_stop_tick() and define tick_nohz_idle_stop_tick()
> > as a wrapper around it for calling it from the outside.
> >
> > Make tick_nohz_idle_enter() only call tick_nohz_start_idle() instead
> > of calling the entire __tick_nohz_idle_enter(), add another wrapper
> > disabling and enabling interrupts around tick_nohz_idle_stop_tick()
> > and make the current callers of tick_nohz_idle_enter() call it too
> > to retain their current functionality.
>
> Perhaps we should have a higher level description of what the patch does.
> After all the low level part is already described in the diff.
>
> Ie: we are splitting the nohz idle entry call to decouple the idle time
> stats accounting and preparatory work from the actual tick stop code, that
> in order to later be able to delay the tick stop once we reach more
> power-knowledgeable callers.

OK