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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     paulmck@kernel.org
Cc:     linux-kernel@vger.kernel.org, john.stultz@linaro.org,
        kernel-team@fb.com, ak@linux.intel.com, rong.a.chen@intel.com,
        sboyd@kernel.org
Subject: Re: [GIT PULL clocksource] Clocksource watchdog commits for v5.15
In-Reply-To: <20210812000133.GA402890@paulmck-ThinkPad-P17-Gen-1>
References: <20210812000133.GA402890@paulmck-ThinkPad-P17-Gen-1>
Date:   Thu, 12 Aug 2021 15:46:42 +0200
Message-ID: <87czqiixml.ffs@tglx>
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On Wed, Aug 11 2021 at 17:01, Paul E. McKenney wrote:
> This pull request contains a single change that prevents clocksource
> watchdog testing on systems with HZ < 100, thus preventing the integer
> underflow that can occur on leisurely HZed systems.  This has been
> posted to LKML:
>
> https://lore.kernel.org/lkml/20210721212755.GA2066078@paulmck-ThinkPad-P17-Gen-1/

So with HZ < 100 .mult overflows, but why not simply adjusting the
mult, shift value to be

      .mult	= TICK_NSEC,
      .shift	= 0,

which is effectively the same as

      .mult	= TICK_NSEC << 8,
      .shift	= 8,

Hmm?

Thanks,

        tglx