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Date: Fri, 17 Feb 2017 12:55:56 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Chris Wilson <chris@chris-wilson.co.uk>
cc: linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
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Subject: Re: [PATCH v3] softirq: Prevent looping on disabled tasklets
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References: <20170212140019.3450-1-chris@chris-wilson.co.uk> <20170212154609.20238-1-chris@chris-wilson.co.uk> <20170212160335.GD14326@nuc-i3427.alporthouse.com>
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On Sun, 12 Feb 2017, Chris Wilson wrote:

> On Sun, Feb 12, 2017 at 03:46:09PM +0000, Chris Wilson wrote:
> > +void tasklet_enable(struct tasklet_struct *t)
> > +{
> > +	if (!atomic_dec_and_test(&t->count))
> > +		return;
> > +
> > +	if (test_bit(TASKLET_STATE_SCHED, &t->state))
> > +		raise_softirq(HI_SOFTIRQ | TASKLET_SOFTIRQ);
> 
> And of course this can't work as raise_softirq() is local to the cpu.

Indeed. tasklets are a horror by design. We rather should make them go away.

Thanks,

	tglx