From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [RFC PATCH 09/18] kthread: Make it easier to correctly sleep in
 iterant kthreads
Date: Wed, 10 Jun 2015 11:07:24 +0200
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To: Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>
Cc: Petr Mladek <pmladek-AlSwsSmVLrQ@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Richard Weinberger <richard-/L3Ra7n9ekc@public.gmane.org>, David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Trond Myklebust <trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>, Anna Schumaker <anna.schumaker-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Chris Mason <clm-b10kYP2dOMg@public.gmane.org>, "Paul E. McKenney" <paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Jiri Kosina <jkosina-AlSwsSmVLrQ@public.gmane.org>, Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, live-patching-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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On Mon, Jun 08, 2015 at 01:48:10PM -0400, Steven Rostedt wrote:
> > commit 80ed87c8a9ca0cad7ca66cf3bbdfb17559a66dcf
> > Author: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.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.