Re: [PATCH 2/6] RFC perf_counter: singleshot support

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Thu, 2009-04-02 at 20:10 +0200, Ingo Molnar wrote:
> * Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> 
> > OK, so I just remembered the sigio thing mentioned by Paul a while 
> > back.
> > 
> > and this should do I suppose...
> 
> > @@ -1561,6 +1578,7 @@ void perf_counter_wakeup(struct perf_cou
> >  	rcu_read_unlock();
> >  
> >  	wake_up_all(&counter->waitq);
> > +	kill_fasync(&counter->fasync, SIGIO, POLL_IN);
> 
> ah, yes.
> 
> Do we even need the explicit signo method this way? The SIGIO target 
> is configurable via fcntl(F_SETSIG), right?

F_SETSIG allows you to change the signal that is delivered, SIGIO by
default, F_SETOWN allows you to specify a target.