Re: [PATCH][RFC] time: add wait_interruptible_timeout macro tosleep (w. timeout) until wake_up

From: Michel Dänzer
Date: Mon Mar 01 2010 - 11:45:30 EST

On Sat, 2010-02-27 at 10:33 +0100, RafaÅ MiÅecki wrote:
> W dniu 26 lutego 2010 20:01 uÅytkownik Ville SyrjÃlà <syrjala@xxxxxx> napisaÅ:
> > Disabling the condition check doesn't make sense.
> >
> > You could use a completion.
> >
> > init_completion(vbl_irq);
> > enable_vbl_irq();
> > wait_for_completion(vbl_irq);
> > disable_vbl_irq();
> > and call complete(vbl_irq) in the interrupt handler.
> >
> > The same would of course work with just some flag or counter
> > and a wait queue.
> Ouch, I can see it gone bad already.
> Firstly I simply just wanted to avoid condition in wait_event_*. It
> looked unnecessary as I got interrupts (signals).

So this code runs in user process context? If so, it should return to
userspace ASAP on signal receipt, otherwise e.g. smoothness of X mouse
movement may suffer.

If that's a problem, then maybe the code should run in a different
context, e.g. a tasklet or some kind of worker kernel thread.

Earthling Michel DÃnzer |
Libre software enthusiast | Debian, X and DRI developer
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