lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

irq: allocate irq_desc_ptrs array based on nr_irqs

Browse Source 
Impact: allocate irq_desc_ptrs in preparation for making it variable-sized.

This addresses this memory usage bump when NR_CPUS bumped from 128 to 4096:

    34816   +229376    264192  +658%  irq_desc_ptrs(.data.read_mostly)

The patch is split into two parts, the first simply allocates the
irq_desc_ptrs array.  Then next will deal with making it variable.
This is only when CONFIG_SPARSE_IRQS=y.

Signed-off-by: Mike Travis <travis@sgi.com>
This commit is contained in:
Mike Travis
2009-01-10 22:24:06 -08:00
committed by Ingo Molnar
parent e2f4d06545
commit 0fa0ebbf15
2 changed files with 16 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/irq/handle.c
View File

@ -17,6 +17,7 @@
#include <linux/kernel_stat.h>
#include <linux/rculist.h>
#include <linux/hash.h>
#include <linux/bootmem.h>
#include "internals.h"
@ -110,7 +111,7 @@ static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
*/
DEFINE_SPINLOCK(sparse_irq_lock);
struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
struct irq_desc **irq_desc_ptrs __read_mostly;
static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
[0 ... NR_IRQS_LEGACY-1] = {
@ -137,6 +138,9 @@ int __init early_irq_init(void)
desc = irq_desc_legacy;
legacy_count = ARRAY_SIZE(irq_desc_legacy);
/* allocate irq_desc_ptrs array based on nr_irqs */
irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
for (i = 0; i < legacy_count; i++) {
desc[i].irq = i;
desc[i].kstat_irqs = kstat_irqs_legacy[i];
@ -153,7 +157,10 @@ int __init early_irq_init(void)
struct irq_desc *irq_to_desc(unsigned int irq)
{
return (irq < nr_irqs) ? irq_desc_ptrs[irq] : NULL;
if (irq_desc_ptrs && irq < nr_irqs)
return irq_desc_ptrs[irq];
return NULL;
}
struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)