linux-kernel - Re: [GIT PULL clocksource] Clocksource watchdog commits for v5.15

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Message-ID: <87czqiixml.ffs@tglx>
Date:   Thu, 12 Aug 2021 15:46:42 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     paulmck@...nel.org
Cc:     linux-kernel@...r.kernel.org, john.stultz@...aro.org,
        kernel-team@...com, ak@...ux.intel.com, rong.a.chen@...el.com,
        sboyd@...nel.org
Subject: Re: [GIT PULL clocksource] Clocksource watchdog commits for v5.15

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