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()
Date: Fri, 23 Sep 2016 11:26:58 +0200 [thread overview]
Message-ID: <20160923092658.GA24285@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1609231111010.5640@nanos>
* 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
next prev parent reply other threads:[~2016-09-23 9:27 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 8:45 [RFC][PATCH] dm: Remove dm_bufio_cond_resched() Peter Zijlstra
2016-09-13 12:49 ` Thomas Gleixner
2016-09-13 13:39 ` Mike Snitzer
2016-09-19 10:53 ` Peter Zijlstra
2016-09-22 20:53 ` Mikulas Patocka
2016-09-22 20:59 ` Thomas Gleixner
2016-09-23 7:34 ` Peter Zijlstra
2016-09-23 8:00 ` Thomas Gleixner
2016-09-23 9:05 ` Peter Zijlstra
2016-09-23 9:13 ` Thomas Gleixner
2016-09-23 9:26 ` Ingo Molnar [this message]
2016-09-23 12:17 ` Mike Galbraith
2016-09-23 12:26 ` Peter Zijlstra
2016-09-23 12:39 ` Mike Galbraith
2016-09-23 12:42 ` Mike Snitzer
2016-09-23 12:46 ` Peter Zijlstra
2016-09-23 14:32 ` [dm-devel] " Bart Van Assche
2016-09-19 9:49 ` Mikulas Patocka
2016-09-19 10:47 ` Peter Zijlstra
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