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Date: Wed, 10 Jun 2015 11:07:24 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.cz>, Andrew Morton <akpm@linux-foundation.org>,
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Subject: Re: [RFC PATCH 09/18] kthread: Make it easier to correctly sleep in
 iterant kthreads
Message-ID: <20150610090724.GD3644@twins.programming.kicks-ass.net>
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On Mon, Jun 08, 2015 at 01:48:10PM -0400, Steven Rostedt wrote:
> > commit 80ed87c8a9ca0cad7ca66cf3bbdfb17559a66dcf
> > Author: Peter Zijlstra <peterz@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.