linux-kernel - Re: [PATCH, v2]

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Date:	Mon, 28 Jul 2014 14:11:35 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
cc:	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org,
	Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH, v2]

On Mon, 28 Jul 2014, Rafael J. Wysocki wrote:
> On Sunday, July 27, 2014 05:53:07 PM Rafael J. Wysocki wrote:
>  irqreturn_t
> +do_irqaction(struct irq_desc *desc, struct irqaction *action,
> +	     unsigned int irq, void *dev_id)
> +{
> +	irqreturn_t ret;
> +
> +	if (unlikely((desc->istate & IRQS_SHARED_SUSPENDED) &&
> +		     !(action->flags & IRQF_NO_SUSPEND)))
> +		return IRQ_NONE;

I really want to avoid that conditional. We burden it on every
interrupt just to deal with this nonsense.

A simple solution for this is to add irq_desc::action_suspended and
move the shared actions which are not flagged NO_SUSPEND over and
bring them back on resume.

> Index: linux-pm/kernel/irq/spurious.c
> ===================================================================
> --- linux-pm.orig/kernel/irq/spurious.c
> +++ linux-pm/kernel/irq/spurious.c
> @@ -275,6 +275,8 @@ try_misrouted_irq(unsigned int irq, stru
>  void note_interrupt(unsigned int irq, struct irq_desc *desc,
>  		    irqreturn_t action_ret)
>  {
> +	int misrouted;
> +
>  	if (desc->istate & IRQS_POLL_INPROGRESS ||
>  	    irq_settings_is_polled(desc))
>  		return;
> @@ -384,6 +386,9 @@ void note_interrupt(unsigned int irq, st
>  		}
>  	}
>  
> +	misrouted = unlikely(try_misrouted_irq(irq, desc, action_ret)) ?
> +			misrouted_irq(irq) : 0;

If the system is suspended, why would we try misrouted irqs at all?
All non wakeup irqs are disabled, so we just spend a gazillion of
cycles for nothing.

Thanks,

	tglx
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