Commit 771ee3b0 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
Browse files

[PATCH] Add a function to handle interrupt affinity setting 



Provide funtions to:
 - check, whether an interrupt can set the affinity
 - pin the interrupt to a given cpu

Necessary for the ability to setup clocksources more flexible (e.g.  use the
different HPET channels per CPU)

[akpm@osdl.org: alpha build fix]
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 950f4427

include/linux/irq.h

+10 −0
Original line number Diff line number Diff line
@@ -238,11 +238,21 @@ static inline void set_pending_irq(unsigned int irq, cpumask_t mask) 


#endif /* CONFIG_GENERIC_PENDING_IRQ */



extern int irq_set_affinity(unsigned int irq, cpumask_t cpumask);

extern int irq_can_set_affinity(unsigned int irq);



#else /* CONFIG_SMP */



#define move_native_irq(x)

#define move_masked_irq(x)



static inline int irq_set_affinity(unsigned int irq, cpumask_t cpumask)

{

	return -EINVAL;

}



static inline int irq_can_set_affinity(unsigned int irq) { return 0; }



#endif /* CONFIG_SMP */



#ifdef CONFIG_IRQBALANCE

kernel/irq/manage.c

+40 −0
Original line number Diff line number Diff line
@@ -38,6 +38,46 @@ void synchronize_irq(unsigned int irq) 
}

EXPORT_SYMBOL(synchronize_irq);



/**

 *	irq_can_set_affinity - Check if the affinity of a given irq can be set

 *	@irq:		Interrupt to check

 *

 */

int irq_can_set_affinity(unsigned int irq)

{

	struct irq_desc *desc = irq_desc + irq;



	if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||

	    !desc->chip->set_affinity)

		return 0;



	return 1;

}



/**

 *	irq_set_affinity - Set the irq affinity of a given irq

 *	@irq:		Interrupt to set affinity

 *	@cpumask:	cpumask

 *

 */

int irq_set_affinity(unsigned int irq, cpumask_t cpumask)

{

	struct irq_desc *desc = irq_desc + irq;



	if (!desc->chip->set_affinity)

		return -EINVAL;



	set_balance_irq_affinity(irq, cpumask);



#ifdef CONFIG_GENERIC_PENDING_IRQ

	set_pending_irq(irq, cpumask);

#else

	desc->affinity = cpumask;

	desc->chip->set_affinity(irq, cpumask);

#endif

	return 0;

}



#endif



/**

kernel/irq/proc.c

+1 −21
Original line number Diff line number Diff line
@@ -16,26 +16,6 @@ static struct proc_dir_entry *root_irq_dir; 


#ifdef CONFIG_SMP



#ifdef CONFIG_GENERIC_PENDING_IRQ

void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)

{

	set_balance_irq_affinity(irq, mask_val);



	/*

	 * Save these away for later use. Re-progam when the

	 * interrupt is pending

	 */

	set_pending_irq(irq, mask_val);

}

#else

void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)

{

	set_balance_irq_affinity(irq, mask_val);

	irq_desc[irq].affinity = mask_val;

	irq_desc[irq].chip->set_affinity(irq, mask_val);

}

#endif



static int irq_affinity_read_proc(char *page, char **start, off_t off,

				  int count, int *eof, void *data)

{
@@ -73,7 +53,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer, 
		   code to set default SMP affinity. */

		return select_smp_affinity(irq) ? -EINVAL : full_count;



	proc_set_irq_affinity(irq, new_value);

	irq_set_affinity(irq, new_value);



	return full_count;

}

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