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x86: arch_probe_nr_irqs

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Impact: save RAM with large NR_CPUS, get smaller nr_irqs

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Mike Travis <travis@sgi.com>
This commit is contained in:
Yinghai Lu 2009-01-12 17:39:24 -08:00 committed by Mike Travis
parent e65e49d0f3
commit 4a046d1754
5 changed files with 26 additions and 12 deletions
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7
arch/x86/include/asm/irq_vectors.h
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@ -115,14 +115,11 @@
# endif
#else
/* 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) ? \
# define NR_IRQS \
((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)

16
arch/x86/kernel/io_apic.c
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@ -3850,6 +3850,22 @@ void __init probe_nr_irqs_gsi(void)
nr_irqs_gsi = nr;
}
#ifdef CONFIG_SPARSE_IRQ
int __init arch_probe_nr_irqs(void)
{
int nr;
nr = ((8 * nr_cpu_ids) > (32 * nr_ioapics) ?
(NR_VECTORS + (8 * nr_cpu_ids)) :
(NR_VECTORS + (32 * nr_ioapics)));
if (nr < nr_irqs && nr > nr_irqs_gsi)
nr_irqs = nr;
return 0;
}
#endif
/* --------------------------------------------------------------------------
ACPI-based IOAPIC Configuration
-------------------------------------------------------------------------- */

1
include/linux/interrupt.h
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@ -467,6 +467,7 @@ int show_interrupts(struct seq_file *p, void *v);
struct irq_desc;
extern int early_irq_init(void);
extern int arch_probe_nr_irqs(void);
extern int arch_early_irq_init(void);
extern int arch_init_chip_data(struct irq_desc *desc, int cpu);

9
kernel/irq/handle.c
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@ -59,10 +59,6 @@ EXPORT_SYMBOL_GPL(nr_irqs);
#ifdef CONFIG_SPARSE_IRQ
#ifndef max_nr_irqs
#define max_nr_irqs(nr_cpus) NR_IRQS
#endif
static struct irq_desc irq_desc_init = {
.irq = -1,
.status = IRQ_DISABLED,
@ -137,9 +133,8 @@ 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);
/* initialize nr_irqs based on nr_cpu_ids */
arch_probe_nr_irqs();
printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
desc = irq_desc_legacy;

5
kernel/softirq.c
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@ -795,6 +795,11 @@ int __init __weak early_irq_init(void)
return 0;
}
int __init __weak arch_probe_nr_irqs(void)
{
return 0;
}
int __init __weak arch_early_irq_init(void)
{
return 0;