Messages in this thread | | | Subject | Re: [PATCH 09/23] clocksource: add block notifier | From | Daniel Walker <> | Date | Wed, 31 Jan 2007 07:25:52 -0800 |
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On Wed, 2007-01-31 at 11:17 +0100, Ingo Molnar wrote: > * Daniel Walker <dwalker@mvista.com> wrote: > > > Adds a call back interface for register/rating change events. This is > > also used later in this series to signal other interesting events. > > This patch adds: > > > +#define CLOCKSOURCE_NOTIFY_REGISTER 1 > > +#define CLOCKSOURCE_NOTIFY_RATING 2 > > +#define CLOCKSOURCE_NOTIFY_FREQ 4 > > and a later patch adds: > > > +#define CLOCKSOURCE_NOTIFY_UNSTABLE 8 > > while i tentatively agree with the introduction of clocksource driver > notifications in general (given any actual real users of that > infrastructure), i can see three problems with your notifier changes: > > firstly, with the full changes applied, CLOCKSOURCE_NOTIFY_RATING is > totally unused (and not even driven by the core clocksource code).
True, ratings are constant so the notification never happens (and never needs to)
> secondly, CLOCKSOURCE_NOTIFY_REGISTER is only used by the core > clocksource code and no register-notifier interface is exposed: this > makes the whole thing an expensive NOP.
I don't know what you mean when you say "no register-notifier interface is exposed" .. The timekeeping code doesn't use this notification , but it really should. It's not that big of an issue since we don't have many clocks in modules..
> thirdly, CLOCKSOURCE_NOTIFY_FREQ is totally unused as well.
Indeed . Consider it dropped.
> (there are tons of examples in the kernel of how to do driver > notification APIs properly.)
Are you referring to the comments above , or something else your seeing in the code?
Daniel
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