lkml.org 
[lkml]   [2011]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 1/2] genirq: Add chip hooks for taking CPUs on/off line.
On Fri, 18 Mar 2011, David Daney wrote:
> --- a/include/linux/irqdesc.h
> +++ b/include/linux/irqdesc.h
> @@ -178,6 +178,12 @@ static inline int irq_has_action(unsigned int irq)
> return desc->action != NULL;
> }
>
> +/* Test to see if the irq is currently enabled */
> +static inline int irq_desc_is_enabled(struct irq_desc *desc)
> +{
> + return desc->depth == 0;
> +}

That want's to go into kernel/irq/internal.h

> #ifndef CONFIG_GENERIC_HARDIRQS_NO_COMPAT
> static inline int irq_balancing_disabled(unsigned int irq)
> {
> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
> index c9c0601..40736f7 100644
> --- a/kernel/irq/chip.c
> +++ b/kernel/irq/chip.c
> @@ -689,3 +689,38 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set)
>
> irq_put_desc_unlock(desc, flags);
> }
> +
> +void irq_cpu_online(unsigned int irq)

Odd function name. It does not reflect that this is for per cpu
interrupts. So something like irq_xxx_per_cpu_irq(irq)
might be a bit more descriptive.

> +{

So that's called on the cpu which goes online, right?

I wonder whether we can add any sanity check to verify this.

Though I would not worry too much about it. Calling that from a cpu
which is not going offline should have enough nasty side effects that
it's noticed during development. :)

> + unsigned long flags;
> + struct irq_chip *chip;
> + struct irq_desc *desc = irq_to_desc(irq);

Needs to check !desc

> + raw_spin_lock_irqsave(&desc->lock, flags);
> +
> + chip = irq_data_get_irq_chip(&desc->irq_data);
> +
> + if (chip && chip->irq_cpu_online)
> + chip->irq_cpu_online(&desc->irq_data,
> + irq_desc_is_enabled(desc));
> +
> + raw_spin_unlock_irqrestore(&desc->lock, flags);
> +}
> +
> +void irq_cpu_offline(unsigned int irq)
> +{
> + unsigned long flags;
> + struct irq_chip *chip;
> + struct irq_desc *desc = irq_to_desc(irq);

See above.

Style nit: I prefer ordering:

+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irq_chip *chip;
+ unsigned long flags;

For some reason, probably because I'm used to it, that's easier to
parse. But don't worry about that, I'll turn it around before sticking
it into git. :)

Otherwise I'm fine with the approach itself.

Though one question remains: should we just iterate over the irq space
and call the online/offline callbacks when available instead of having
the arch code do the iteration.

Thanks,

tglx


\
 
 \ /
  Last update: 2011-03-19 21:53    [W:0.905 / U:31.916 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site