* Tejun Heo <htejun@xxxxxxxxx> wrote:
> Ingo Molnar wrote:
> > * Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
> >
> >> On Sun, 23 Nov 2008, Tejun Heo wrote:
> >>
> >>> +static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
> >>> +{
> >>> + struct poll_wqueues *pwq = wait->private;
> >>> + DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
> >>> +
> >>> + set_mb(pwq->triggered, 1);
> >>> +
> >>> + /* perform the default wake up operation */
> >>> + return default_wake_function(&dummy_wait, mode, sync, key);
> >>> +}
> >> Wouldn't it be nicer to un-static try_to_wake_up() (or a wrapper)
> >> instead of setting up a fake wait queue just to use
> >> default_wake_function(), just to wake up a task?
> >
> > the already existing single-task-wakeup shortcut method made available
> > by the scheduler is wake_up_process(). A number of primitives where
> > waitqueue overhead is of concern already make use of it.
> > (mutexes/rtmutexes and more)
> >
> > if you need a different mode flag, then please extend the
> > wake_up_process() family of APIs.
>
> Well, the problem is that for wait wake up functions @mode and @sync
> are passed as parameter and should be passed over to actual wake up
> function as-is, if I add @mode and @sync to wake_up_process() family
> of APIs, it's just try_to_wake_up().
_sync() is not something that should normally be done from poll
handlers. But ->poll() handlers should all be TASK_INTERRUPTIBLE,
right? So wake_up_process_interruptible() should be the thing you
need?
Anyway, if you really want to pass in a state filter, you can use the
already existing wake_up_state() method as well.
Ingo
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