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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: David Woodhouse <dwmw2@infradead.org>
Subject: Re: [RFC] schedule_timeout_range()
Date: Tue, 22 Jul 2008 14:50:09 +1000
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Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@elte.hu>, arjan@infradead.org
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On Tuesday 22 July 2008 14:45, David Woodhouse wrote:
> On Tue, 2008-07-22 at 14:33 +1000, Nick Piggin wrote:
> > The only thing I dislike about explicit times is that when a driver or
> > someone doesn't _really_ know how much to specify. Do you say 10s, 100s?
>
> This is true, but they certainly have a _better_ idea than we do. If the
> individual callers can't even come up with an answer, how are we ever
> going to come up with a generic policy that does the right thing?

OK, how about still having a never-until-machine-is-already-awake?


> I really don't think that applying this kind of policy in generic code
> is useful -- I'd like the callers to provide numbers even if they _do_
> pull it out of their wossname.
>
> The number they provide is the _maximum_ amount of time they should be
> prepared to wait (let's assume for a moment that they stayed sober and
> remembered Linux isn't a real-time kernel, so all guarantees are taken
> with a pinch of salt. Let's not get bogged down in nomenclature).

Well, I think it is still wise to avoid words like deadline, hard,
and timeout in the same sentence ;)


> In practice, they'll almost always get called before that maximum time
> expires -- that's the whole _point_, of course. But we can't _invent_
> that maximum in generic code; that's really up to the caller.

Not a maximum, but just an "I don't know... a lot?" define. But yeah
I guess there aren't too many good reasons for that.
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