[RFC PATCH 09/18] kthread: Make it easier to correctly sleep in iterant kthreads

[Peter Zijlstra]

On Mon, Jun 08, 2015 at 01:48:10PM -0400, Steven Rostedt wrote:
> > commit 80ed87c8a9ca0cad7ca66cf3bbdfb17559a66dcf
> > Author: Peter Zijlstra <peterz at infradead.org>
> > Date:   Fri May 8 14:23:45 2015 +0200
> > 
> >     sched/wait: Introduce TASK_NOLOAD and TASK_IDLE
> >     
> >     Currently people use TASK_INTERRUPTIBLE to idle kthreads and wait for
> >     'work' because TASK_UNINTERRUPTIBLE contributes to the loadavg. Having
> >     all idle kthreads contribute to the loadavg is somewhat silly.
> 
> Not to mention, tasks in TASK_UNINTERRUPTIBLE state for too long will
> trigger hung task detection.

Right, and I had not considered that, but it turns out the hung_task
detector checks p->state == TASK_UNINTERRUPTIBLE, so TASK_IDLE is indeed
safe from that.