Re: [PATCH v4] introduce macro spin_event_timeout()

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> But that's the thing - I don't want a required delay inside the loop.
> 
> I guess I'm going to have to think about this for a while.  I'd like
> to see something like cycles_per_usec() as a companion function to
> get_cycles().

I think that's where you're wrong :-)

Just require the delay inside the loop, it will make everything nicer.
There are also some good reasons to do that:

 - The delay between "polls" of the register may have to be controlled,
for example some HW will choke if polled too fast

 - If you aren't in an atomic section, you may want to use msleep() and
thus be schedule friendly

 - It fixes all the problems mentioned earlier

Cheers,
Ben.