livepatch: change to a per-task consistency model

[David Laight]

From: Jiri Kosina
> Sent: 18 May 2016 21:23
> On Wed, 18 May 2016, Josh Poimboeuf wrote:
> 
> > Yeah, I think this situation -- a task sleeping on an affected function
> > in uninterruptible state for a long period of time -- would be
> > exceedingly rare and not something we need to worry about for now.
> 
> Plus in case task'd be in TASK_UNINTERRUPTIBLE for more than 120s, hung
> task detector would trigger anyway.

Related, please can we have a flag for the sleep and/or process so that
an uninterruptible sleep doesn't trigger the 'hung task' detector
and also stops the process counting towards the 'load average'.

In particular some kernel threads are not signalable, and do not
want to be woken by signals (they exit on a specific request).

	David