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From: Thomas Gleixner <tglx@linutronix.de>
To: paulmck@kernel.org
Cc: John Stultz <jstultz@google.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Stephen Boyd <sboyd@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	x86@kernel.org
Subject: Re: [PATCH] clocksource: disable irq when holding watchdog_lock.
Date: Tue, 17 Oct 2023 08:49:46 +0200	[thread overview]
Message-ID: <8734y97ng5.ffs@tglx> (raw)
In-Reply-To: <ae4e5836-bc42-42fa-bd41-2a2fd483acb5@paulmck-laptop>

On Mon, Oct 16 2023 at 16:03, Paul E. McKenney wrote:
> On Mon, Oct 16, 2023 at 11:47:55PM +0200, Thomas Gleixner wrote:
>> That said, this whole clocksource watchdog mess wants a proper
>> overhaul. It has become a pile of warts and duct tape by now and after
>> staring at it long enough there is no real reason to run it in a timer
>> callback anymore. It just can move into delayed work and the whole
>> locking problem can be reduced to the clocksource_mutex and some well
>> thought out atomic operations to handle the mark unstable case. But
>> that's a different story and not relevant for curing the problem at
>> hand.
>
> Moving the code to delayed work seems quite reasonable.
>
> But Thomas, you do understand that the way things have been going for
> the clocksource watchdog, pushing it out to delayed work will no doubt
> add yet more hair on large busy systems, right?  Yeah, yeah, I know,
> delayed work shouldn't be any worse than ksoftirqd.  The key word of
> course being "shouldn't".  ;-)

Yes, I'm aware of that. I still think it's worth at least to try it.

Thanks,

        tglx

  reply	other threads:[~2023-10-17  6:49 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-13 14:51 [PATCH] clocksource: disable irq when holding watchdog_lock Tetsuo Handa
2023-10-16 17:46 ` John Stultz
2023-10-16 21:47   ` Thomas Gleixner
2023-10-16 23:03     ` Paul E. McKenney
2023-10-17  6:49       ` Thomas Gleixner [this message]
2023-10-17 14:11         ` Paul E. McKenney
2023-10-17 10:37     ` Tetsuo Handa
2023-10-17 14:10       ` Paul E. McKenney
2023-10-19  9:30         ` Tetsuo Handa
2023-10-19 12:14           ` Thomas Gleixner
2023-10-19 14:26             ` Tetsuo Handa
2023-10-20  3:30               ` Paul E. McKenney
2023-10-20 12:50                 ` Tetsuo Handa
2023-10-20 13:40                   ` Paul E. McKenney
2023-10-24 13:00               ` Thomas Gleixner
2023-10-24 14:52                 ` Tetsuo Handa
2023-10-25 21:28                   ` Thomas Gleixner
2023-10-25 21:31       ` [PATCH] x86/tsc: Defer marking TSC unstable to a worker Thomas Gleixner
2023-10-26  9:39         ` [tip: x86/urgent] " tip-bot2 for Thomas Gleixner
2023-10-27 18:46         ` tip-bot2 for Thomas Gleixner
2023-10-20  9:02     ` [PATCH] clocksource: disable irq when holding watchdog_lock Sebastian Andrzej Siewior
2023-10-26  2:33 ` kernel test robot

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