From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>,
Bruce Schlobohm <bruce.schlobohm@intel.com>,
Roland Scheidegger <rscheidegger_lists@hispeed.ch>,
Kevin Stanton <kevin.b.stanton@intel.com>,
Allen Hung <allen_hung@dell.com>,
stable@vger.kernel.org
Subject: Re: [patch 2/2] x86/tsc: Force TSC_ADJUST register to value >= zero
Date: Fri, 16 Dec 2016 12:52:54 +0100 [thread overview]
Message-ID: <20161216115254.GA18902@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1612161121140.3470@nanos>
* Thomas Gleixner <tglx@linutronix.de> wrote:
> We have two options:
>
> 1) Disable TSC deadline timer by default and force users with sane machines
> to enable it on the kernel command line.
>
> Upside: Very small patch
>
> Downside: Degrades existing setups on sane machines, keeps TSC unusable
> on affected machines. We have no idea what other hidden side
> effects the TSC_ADJUST tinkering has. If there are any, they
> ain't be nice ones.
>
> 2) Push the whole TSC_ADJUST sanitizing machinery into stable
>
> Upside: Does not affect sane machines and gives a benefit to users of
> affected machines
>
> Downside: Rather large patch, but not that risky either. Needs a few
> eyes and good test coverage though
>
> Thoughts?
I'd go for #2, because #1 is essentially turning it off for almost everyone.
We can still do #1 and push it back to -stable as well if #2 fails.
But I'd suggest we delay the stable backporting until it's been upstream a bit.
Thanks,
Ingo
next prev parent reply other threads:[~2016-12-16 12:00 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-13 13:14 [patch 0/2] tsc/adjust: Cure suspend/resume issues and prevent TSC deadline timer irq storm Thomas Gleixner
2016-12-13 13:14 ` [patch 1/2] x86/tsc: Validate TSC_ADJUST after resume Thomas Gleixner
2016-12-13 13:22 ` Peter Zijlstra
2016-12-13 13:23 ` Thomas Gleixner
2016-12-15 10:52 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2016-12-13 13:14 ` [patch 2/2] x86/tsc: Force TSC_ADJUST register to value >= zero Thomas Gleixner
2016-12-13 13:43 ` Peter Zijlstra
2016-12-13 15:49 ` Thomas Gleixner
2016-12-15 10:53 ` [tip:x86/timers] " tip-bot for Thomas Gleixner
2016-12-16 11:46 ` [patch 2/2] " Thomas Gleixner
2016-12-16 11:52 ` Ingo Molnar [this message]
2016-12-16 11:53 ` Thomas Gleixner
2016-12-16 13:33 ` Thomas Gleixner
2016-12-13 16:34 ` [patch 0/2] tsc/adjust: Cure suspend/resume issues and prevent TSC deadline timer irq storm Roland Scheidegger
2016-12-13 16:46 ` Thomas Gleixner
2016-12-14 1:36 ` Roland Scheidegger
2016-12-14 7:31 ` Thomas Gleixner
2016-12-14 20:59 ` Thomas Gleixner
2016-12-14 21:40 ` Thomas Gleixner
2016-12-14 22:54 ` Roland Scheidegger
2016-12-15 9:31 ` Thomas Gleixner
2017-01-26 23:40 ` Stanton, Kevin B
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