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Date:   Tue, 12 Dec 2023 14:37:01 +0100
From:   Frederic Weisbecker <frederic@kernel.org>
To:     Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc:     Sebastian Siewior <bigeasy@linutronix.de>,
        linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        John Stultz <jstultz@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Eric Dumazet <edumazet@google.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Arjan van de Ven <arjan@infradead.org>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Rik van Riel <riel@surriel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Giovanni Gherdovich <ggherdovich@suse.cz>,
        Lukasz Luba <lukasz.luba@arm.com>,
        "Gautham R . Shenoy" <gautham.shenoy@amd.com>,
        Srinivas Pandruvada <srinivas.pandruvada@intel.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>
Subject: Re: [PATCH v9 12/32] timers: Fix nextevt calculation when no timers
 are pending
Message-ID: <ZXhh/RwjhvrBJsaV@lothringen>
References: <20231201092654.34614-1-anna-maria@linutronix.de>
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On Tue, Dec 12, 2023 at 02:21:25PM +0100, Anna-Maria Behnsen wrote:
> Frederic Weisbecker <frederic@kernel.org> writes:
> 
> > Le Tue, Dec 05, 2023 at 12:53:03PM +0100, Anna-Maria Behnsen a écrit :
> >> 
> >> Frederic, what do you think?
> >
> > So it looks like is_idle must be fixed.
> >
> > As for the timer softirq, ->next_expiry is already unreliable because when
> > a timer is removed, ->next_expiry is not updated (even though that removed
> > timer might have been the earliest). So ->next_expiry can already carry a
> > "too early" value. The only constraint is that ->next_expiry can't be later
> > than the first timer.
> >
> > So I'd rather put a comment somewhere about the fact that wrapping is expected
> > to behave ok. But it's your call.
> 
> Ok. If both solutions are fine, I would like to take the solution with
> updating the next_expiry values for empty bases. It will make the
> compare of expiry values of global and local timer base easier in one of
> the patches later on.

Fine by me at least!

Thanks.

> Thanks,
> 
> 	Anna-Maria
>