RFC: Allow block drivers to poll for I/O instead of sleeping

[Steven Rostedt]

On Mon, Jun 24, 2013 at 09:17:18AM +0200, Jens Axboe wrote:
> On Sun, Jun 23 2013, Linus Torvalds wrote:
> > 
> > You could try to do that either *in* the idle thread (which would take
> > the context switch overhead - maybe negating some of the advantages),
> > or alternatively hook into the scheduler idle logic before actually
> > doing the switch.
> 
> It can't happen in the idle thread. If you need to take the context
> switch, then you've negated pretty much all of the gain of the polled
> approach.

What about hooking into the idle_balance code? That happens if we are
about to go to idle but before the full schedule switch to the idle
task.


In __schedule(void):

	if (unlikely(!rq->nr_running))
		idle_balance(cpu, rq);

-- Steve