Re: [v3 1/2] sched/clock: interface to allow timestamps early in boot

[Dou Liyang]

Hi Pasha,

At 08/14/2017 11:44 PM, Pasha Tatashin wrote:
> Hi Dou,
>
> Thank you for your comments:
>
> > >  {
> > >      x86_init.timers.timer_init();
> > >      tsc_init();
> > > +    tsc_early_fini();
> >
> > tsc_early_fini() is defined in patch 2, I guess you may miss it
> > when you split your patches.
>
> Indeed, I will move it to patch 2.
>
> > > +static DEFINE_STATIC_KEY_TRUE(__use_sched_clock_early);
> > > +static bool __read_mostly sched_clock_early_running;
> > > +
> >
> > In my opinion, these two parameters are repetitive, I suggest remove
> > one.
> >
> > eg. remove sched_clock_early_running like below
> > First, static DEFINE_STATIC_KEY_FALSE(__use_sched_clock_early);
>
> We can't change the static branches before jump_label_init() is called,
> and we start early boot timestamps before that

I understood, I was wrong, thanks for your explanation.

Thanks
	dou.

> This is why having two booleans is appropriate: one that can be changed
> early in boot, and another to patch the hotcode in order to keep good
> performance after boot.
>
> I will update comment before __use_sched_clock_early explaining the
> reason why we need two of them.
>
> Thank you,
> Pasha