Commit 9332fccd authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
Browse files

irq: initialize nr_irqs based on nr_cpu_ids 



Impact: Reduce memory usage.

This is the second half of the changes to make the irq_desc_ptrs be
variable sized based on nr_cpu_ids.  This is done by adding a new
"max_nr_irqs" macro to irq_vectors.h (and a dummy in irqnr.h) to
return a max NR_IRQS value based on NR_CPUS or nr_cpu_ids.

This necessitated moving the define of MAX_IO_APICS to a separate
file (asm/apicnum.h) so it could be included without the baggage
of the other asm/apicdef.h declarations.

Signed-off-by: default avatarMike Travis <travis@sgi.com>
parent 0fa0ebbf

arch/x86/include/asm/apicdef.h

+2 −6
Original line number Diff line number Diff line
@@ -132,12 +132,8 @@ 
#define APIC_BASE_MSR	0x800

#define X2APIC_ENABLE	(1UL << 10)



#ifdef CONFIG_X86_32

# define MAX_IO_APICS 64

#else

# define MAX_IO_APICS 128

# define MAX_LOCAL_APIC 32768

#endif

/* get MAX_IO_APICS */

#include <asm/apicnum.h>



/*

 * All x86-64 systems are xAPIC compatible.

arch/x86/include/asm/apicnum.h

0 → 100644
+12 −0
Original line number Diff line number Diff line 
#ifndef _ASM_X86_APICNUM_H

#define _ASM_X86_APICNUM_H



/* define MAX_IO_APICS */

#ifdef CONFIG_X86_32

# define MAX_IO_APICS 64

#else

# define MAX_IO_APICS 128

# define MAX_LOCAL_APIC 32768

#endif



#endif /* _ASM_X86_APICNUM_H */

arch/x86/include/asm/irq_vectors.h

+11 −5
Original line number Diff line number Diff line
@@ -105,6 +105,8 @@ 


#if defined(CONFIG_X86_IO_APIC) && !defined(CONFIG_X86_VOYAGER)



#include <asm/apicnum.h>	/* need MAX_IO_APICS */



#ifndef CONFIG_SPARSE_IRQ

# if NR_CPUS < MAX_IO_APICS

#  define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
@@ -112,11 +114,15 @@ 
#  define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))

# endif

#else

# if (8 * NR_CPUS) > (32 * MAX_IO_APICS)

#  define NR_IRQS (NR_VECTORS + (8 * NR_CPUS))

# else

#  define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))

# endif



/* defined as a macro so nr_irqs = max_nr_irqs(nr_cpu_ids) can be used */

# define max_nr_irqs(nr_cpus)				\

	((8 * nr_cpus) > (32 * MAX_IO_APICS) ?		\

		(NR_VECTORS + (8 * NR_CPUS)) :		\

		(NR_VECTORS + (32 * MAX_IO_APICS)))	\



# define NR_IRQS max_nr_irqs(NR_CPUS)



#endif



#elif defined(CONFIG_X86_VOYAGER)

include/linux/irqnr.h

+7 −0
Original line number Diff line number Diff line
@@ -20,11 +20,18 @@ 


# define for_each_irq_desc_reverse(irq, desc)                          \

	for (irq = nr_irqs - 1; irq >= 0; irq--)



#else /* CONFIG_GENERIC_HARDIRQS */



#include <asm/irq_vectors.h>	/* need possible max_nr_irqs() */



extern int nr_irqs;

extern struct irq_desc *irq_to_desc(unsigned int irq);



# ifndef max_nr_irqs

#  define max_nr_irqs(nr_cpus)	NR_IRQS

# endif



# define for_each_irq_desc(irq, desc)					\

	for (irq = 0, desc = irq_to_desc(irq); irq < nr_irqs;		\

	     irq++, desc = irq_to_desc(irq))				\

kernel/irq/handle.c

+3 −0
Original line number Diff line number Diff line
@@ -133,6 +133,9 @@ int __init early_irq_init(void) 
	int legacy_count;

	int i;



	/* initialize nr_irqs based on nr_cpu_ids */

	nr_irqs = max_nr_irqs(nr_cpu_ids);



	printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);



	desc = irq_desc_legacy;

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