Re: question on resume()

From: Rafael J. Wysocki
Date: Wed Jan 31 2007 - 03:48:35 EST


On Wednesday, 31 January 2007 09:40, Oliver Neukum wrote:
> Am Mittwoch, 31. Januar 2007 09:33 schrieb Rafael J. Wysocki:
> > On Tuesday, 30 January 2007 23:32, Rafael J. Wysocki wrote:
>
> > > Generally, you are safe if your driver only calls wake_up() from a process
> > > context, but not from .resume() or .suspend() routines (or from an
> > > unfreezeable kernel thread).
> >
> > Ah, sorry, I've just realized I was wrong. Processes in TASK_UNINTERRUPTIBLE
> > cannot be frozen! So, the above only applies to wake_up_interruptible().
>
> So the kernel will wait for tasks in TASK_UNINTERRUPTIBLE to finish IO
> before it calls suspend()? I am confused.

Yes, it will. The process freezer can only return success if there are no more
TASK_UNINTERRUPTIBLE tasks. Otherwise it fails (after a timeout).

Greetings,
Rafael


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