Messages in this thread | | | Date | Thu, 30 Jul 2009 17:42:51 +0200 | From | Martin Schwidefsky <> | Subject | Re: [RFC][patch 00/12] clocksource / timekeeping rework V2 |
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On Thu, 30 Jul 2009 07:49:12 -0600 dwalker@fifo99.com wrote:
> On Thu, 2009-07-30 at 15:04 +0200, Martin Schwidefsky wrote: > > On Thu, 30 Jul 2009 05:49:33 -0700 > > Daniel Walker <dwalker@fifo99.com> wrote: > > > > > On Thu, 2009-07-30 at 12:53 +0200, Martin Schwidefsky wrote: > > > > > > > > I'm not sure allowing that type of override a good idea tho .. I don't > > > > > think it's considered a usable clock when the rating goes to zero. > > > > > > > > Override as the root user -> your foot, no? The whole override stuff is > > > > there for the case that the clocksource selection picked a broken clock > > > > and you want to force the system into a semi-working state. Ideally the > > > > whole override would go away, but that is probably wishful thinking.. > > > > > > I would agree if the system doesn't crash as a result, if it just starts > > > to operate funny then that's maybe acceptable. If you keep the change > > > rating function, you could potentially remove the unregister path.. > > > > Why shouldn't it be possible to have a clocksource as a module? I think > > that the unregister path should stay. To really make it work we'd need > > a function to force the system out of the one-shot mode though. > > Because I don't think there is a sane reason to allow it. It should be > more like if someone has a need for it, then let them add back the > unregister path and explain why they need it.
I hear your. Without the need to unregister a clock the whole watchdog unregistration can be dropped as well before it ever has been added.
There are currently two clocksources that use clocksource_unregister, the pit clock and the sgi_rtc clock. The sgi_rtc clock in arch/x86/kernel/uv_time.c could be modified slightly to avoid the clocksource_unregister call. The pit clock in arch/x86/kernel/i8253.c is odd, it uses clocksource_unregister in the set_mode callback if the mode is set to SHUTDOWN, UNUSED or ONESHOT. Very strange..
-- blue skies, Martin.
"Reality continues to ruin my life." - Calvin.
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