linux-kernel - Re: clocksource: Reduce watchdog readout delay limit to prevent false positives

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Message-ID: <87tsxla6qz.ffs@tglx>
Date: Sat, 20 Dec 2025 09:37:40 +0100
From: Thomas Gleixner <tglx@...utronix.de>
To: paulmck@...nel.org
Cc: LKML <linux-kernel@...r.kernel.org>, Daniel J Blueman
 <daniel@...ra.org>, John Stultz <jstultz@...gle.com>, Waiman Long
 <longman@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Dave Hansen
 <dave.hansen@...ux.intel.com>, Tony Luck <tony.luck@...el.com>, Borislav
 Petkov <bp@...en8.de>, Stephen Boyd <sboyd@...nel.org>, Scott Hamilton
 <scott.hamilton@...den.com>
Subject: Re: clocksource: Reduce watchdog readout delay limit to prevent
 false positives

On Fri, Dec 19 2025 at 16:18, Paul E. McKenney wrote:
> On Fri, Dec 19, 2025 at 11:13:05AM +0100, Thomas Gleixner wrote:
>> > My concern is that the patch below would force needless cs_watchdog_read()
>> > retries.
>> 
>> That's not the end of the world and way better than degrading the
>> watchdog further.
>
> But what you proposed is just a further tweak of the heuristics you so
> energetically decry above.

I fully agree that it is a bandaid fix, but it makes the machinery
consistent and correct. It prevents false positives, which are
inevitable in the current design. No?

Thanks,

        tglx