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Subject: Re: [patch 0/2] Run interrupt handlers always with interrupts
 disabled
From: Peter Zijlstra <peterz@infradead.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
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Date: Fri, 26 Mar 2010 11:08:53 +0100
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On Fri, 2010-03-26 at 09:59 +0000, Alan Cox wrote:
> > As long as it's rare (which it is) i dont see a problem: you can enable 
> > interrupts in the handler by using local_irq_enable(), like the IDE PIO 
> > drivers do. That way it's documented a bit better as well, because it shows 
> > the precise source of the latency, with a big comment explaining it, etc.
> 
> I don't think it's as rare as you think particularly in embedded, and the
> moment you start explicitly using local_irq_enable() you've simply moved
> the underlying problem back and made it far harder to grep for.

We've got local_irq_enable_in_hardirq() which should be used and can
easily be grep'ed for.

But yes, I would much prefer to simply convert these known slow handlers
to threaded interrupts.