From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Oliver Neukum <oliver@neukum.name>
Subject: Re: question on resume()
Date: Wed, 31 Jan 2007 09:49:03 +0100
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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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