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From: Alex Shi <alex.shi@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@linux.intel.com, tim.c.chen@linux.intel.com,
	linux-kernel@vger.kernel.org, andi.kleen@intel.com,
	a.p.zijlstra@chello.nl, mingo@elte.hu
Subject: Re: [PATCH 1/3] clocksource: clean up clocksource_select
Date: Thu, 04 Jul 2013 18:21:49 +0800	[thread overview]
Message-ID: <51D54CBD.1010400@intel.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1307041151170.11637@ionos.tec.linutronix.de>


> We need this check and it is completely unrelated to the problem
> you're trying to solve.
> 
> Assume the following:
> 
>        System boots with clocksource A and switches into highres mode.
>        Now clocksource B gets registered and B is not highres capable.
> 
>        clocksource_find_best() selects again A, but we have
>        clocksource=B on the kernel command line to override the kernel
>        decision.
> 
> By removing the check, you install he non highres capable clocksource
> B and kill the machine.
> 

You'r right. my bad, Sorry!

BTW, why we allow user override a second best clocksource? I mean user
can override the tsc with hpet. because undetected unstable tsc?



-- 
Thanks
    Alex

  reply	other threads:[~2013-07-04 10:22 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-04  5:34 [URGENT rfc patch 0/3] tsc clocksource bug fix Alex Shi
2013-07-04  5:34 ` [PATCH 1/3] clocksource: clean up clocksource_select Alex Shi
2013-07-04  9:57   ` Thomas Gleixner
2013-07-04 10:21     ` Alex Shi [this message]
2013-07-04 10:27       ` Thomas Gleixner
2013-07-05  1:22         ` Alex Shi
2013-07-04  5:34 ` [PATCH 2/3] clockesource: set override clocksource Alex Shi
2013-07-04 10:23   ` Thomas Gleixner
2013-07-04  5:34 ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-04 10:55   ` Thomas Gleixner
2013-07-04 13:04     ` Thomas Gleixner
2013-07-04 20:46       ` [PATCH] clocksource: Reselect clocksource when watchdog validated Thomas Gleixner
2013-07-05  1:38         ` Alex Shi
2013-07-05  9:13         ` [tip:timers/core] clocksource: Reselect clocksource when watchdog validated high-res capability tip-bot for Thomas Gleixner
2013-07-05  2:48       ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-05  5:41         ` Thomas Gleixner
2013-07-05  6:44           ` Alex Shi
2013-07-04  7:58 ` [URGENT rfc patch 0/3] tsc clocksource bug fix Peter Zijlstra
2013-07-04  8:13   ` Alex Shi
2013-07-05 14:23   ` Frederic Weisbecker
2013-07-05 14:38     ` Peter Zijlstra
2013-07-05 15:24       ` Thomas Gleixner
2013-07-05 21:22         ` Peter Zijlstra
2013-07-05 21:50           ` Thomas Gleixner
2013-07-05 21:58             ` Borislav Petkov
2013-07-05 22:17               ` Thomas Gleixner
2013-07-06  8:37                 ` Borislav Petkov
2013-07-06 10:50             ` Peter Zijlstra
2013-07-04 11:00 ` Thomas Gleixner
2013-07-04 18:11   ` Davidlohr Bueso
2013-07-04 20:27     ` Thomas Gleixner
2013-07-05  1:12       ` Alex Shi
2013-07-05  5:58         ` Thomas Gleixner
2013-07-05  6:28           ` Alex Shi

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