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Date: Fri, 23 Sep 2016 11:26:58 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
        Mikulas Patocka <mpatocka@redhat.com>,
        Mike Snitzer <snitzer@redhat.com>, Alasdair Kergon <agk@redhat.com>,
        linux-kernel@vger.kernel.org, dm-devel@redhat.com,
        Joe Thornber <ejt@redhat.com>
Subject: Re: [RFC][PATCH] dm: Remove dm_bufio_cond_resched()
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* Thomas Gleixner <tglx@linutronix.de> wrote:

> On Fri, 23 Sep 2016, Peter Zijlstra wrote:
> > On Fri, Sep 23, 2016 at 10:00:37AM +0200, Thomas Gleixner wrote:
> > > On Fri, 23 Sep 2016, Peter Zijlstra wrote:
> > > > It is, might_sleep() implies might_resched(). In fact, that's all what
> > > > PREEMPT_VOLUNTARY is, make the might_sleep() debug test imply a resched
> > > > point.
> > > 
> > > Grr, how intuitive - NOT!
> > 
> > No, it actually makes sense. Because you 'obviously' only call
> > might_sleep() in contexts that should be able to sleep (if not, it'll
> > holler). So they're already placed right for preemption.
> 
> I disagree. might_sleep() is commonly known as a debug mechanism and it
> existed before the preemption stuff went in. So the easy way to sprinkle
> preemption points into the kernel was to hijack might_sleep(). I know it's
> historical, but that doesnt make it any more intuitive.

If we rename it to might_as_well_sleep() it becomes more intuitive! ;-)

Thanks,

	Ingo