Re: [RFC][PATCH 2/2] time: alarmtimer: Use TASK_FREEZABLE to cleanup freezer handling

[Michael Nazzareno Trimarchi]

Hi Thomas

On Thu, Mar 2, 2023 at 11:58 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> On Thu, Mar 02 2023 at 23:21, Thomas Gleixner wrote:
> > On Thu, Mar 02 2023 at 15:32, Rafael J. Wysocki wrote:
> >> On Mon, Feb 20, 2023 at 10:19 PM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >>> +static atomic_t alarmtimer_wakeup;
> >>>
> >>>  /**
> >>>   * alarmtimer_fired - Handles alarm hrtimer being fired.
> >>> @@ -194,6 +196,8 @@ static enum hrtimer_restart alarmtimer_f
> >>>         int ret = HRTIMER_NORESTART;
> >>>         int restart = ALARMTIMER_NORESTART;
> >>>
> >>> +       atomic_inc(&alarmtimer_wakeup);
> >>> +
> >>
> >> This appears to be still somewhat racy, because the notifier can run
> >> at this point AFAICS.
> >
> > Indeed it is. Let me think more about this.
>
> All of this is inherently racy as there is zero feedback whether the
> event has been consumed or not. Making this feedback based is not
> necessarily trivial, but let me stare into that.
>

Sorry to come back on this topic but I would like to know, if we can
find a way to be sure
to not lost wakeup or if you have already addressed in some series

Michael


> Thanks,
>
>         tglx
>


-- 
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael@xxxxxxxxxxxxxxxxxxxx
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