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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     Marcelo Tosatti <mtosatti@redhat.com>
Cc:     Anna-Maria Behnsen <anna-maria@linutronix.de>,
        linux-kernel@vger.kernel.org,
        Frederic Weisbecker <frederic@kernel.org>,
        Peter Xu <peterx@redhat.com>,
        Nitesh Narayan Lal <nitesh@redhat.com>,
        Alex Belits <abelits@marvell.com>
Subject: Re: [PATCH v3] hrtimer: avoid retrigger_next_event IPI
In-Reply-To: <20210415153935.GA69750@fuller.cnet>
References: <20210407135301.GA16985@fuller.cnet> <87o8en4k9a.ffs@nanos.tec.linutronix.de> <20210409165146.GA40118@fuller.cnet> <87lf9q4lue.ffs@nanos.tec.linutronix.de> <20210413170431.GA16190@fuller.cnet> <20210415153935.GA69750@fuller.cnet>
Date:   Thu, 15 Apr 2021 20:59:30 +0200
Message-ID: <87im4nv0fh.ffs@nanos.tec.linutronix.de>
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On Thu, Apr 15 2021 at 12:39, Marcelo Tosatti wrote:
> +static bool need_reprogram_timer(struct hrtimer_cpu_base *cpu_base)
> +{
> +	unsigned int active = 0;
> +
> +	if (cpu_base->softirq_activated)
> +		return true;
> +
> +	active = cpu_base->active_bases & HRTIMER_ACTIVE_SOFT;
> +	active = active | (cpu_base->active_bases & HRTIMER_ACTIVE_HARD);

It's not entirely clear to me what that 'active' variable business above
is doing and why it's needed at all. But I might be missing something.

> +	return (cpu_base->active_bases & CLOCK_SET_BASES) != 0;
> +}