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Commit 542d865b authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
Browse files

kstat: modify kstat_irqs_legacy to be variable sized 



Impact: reduce memory usage.

Allocate kstat_irqs_legacy based on nr_cpu_ids to deal with this
memory usage bump when NR_CPUS bumped from 128 to 4096:

     8192   +253952    262144 +3100%  kstat_irqs_legacy(.bss)

This is only when CONFIG_SPARSE_IRQS=y.

Signed-off-by: default avatarMike Travis <travis@sgi.com>
parent 9332fccd

kernel/irq/handle.c

+7 −3
Original line number Diff line number Diff line
@@ -124,8 +124,7 @@ static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_sm 
	}

};



/* FIXME: use bootmem alloc ...*/

static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];

static unsigned int *kstat_irqs_legacy;



int __init early_irq_init(void)

{
@@ -144,9 +143,14 @@ int __init early_irq_init(void) 
	/* allocate irq_desc_ptrs array based on nr_irqs */

	irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));



	/* allocate based on nr_cpu_ids */

	/* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */

	kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *

					  sizeof(int));



	for (i = 0; i < legacy_count; i++) {

		desc[i].irq = i;

		desc[i].kstat_irqs = kstat_irqs_legacy[i];

		desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;

		lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);

		init_alloc_desc_masks(&desc[i], 0, true);

		irq_desc_ptrs[i] = desc + i;