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authorMike Travis <travis@sgi.com>2009-01-10 22:24:06 -0800
committerIngo Molnar <mingo@elte.hu>2009-01-11 19:13:35 +0100
commit0fa0ebbf15addc1be8f73325d809c8547a9de304 (patch)
treecd995419a3eb84d3e18e92ff205af86a7a4ed66d /kernel/irq
parente2f4d06545ec1f29b0e838ee34cbf3500ea5b9a4 (diff)
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irq: allocate irq_desc_ptrs array based on nr_irqs
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>
Diffstat (limited to 'kernel/irq')
-rw-r--r--kernel/irq/handle.c11
-rw-r--r--kernel/irq/internals.h7
2 files changed, 16 insertions, 2 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index fd1ef16..d0b8f7e 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -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)
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index e6d0a43..40416a8 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -16,7 +16,14 @@ extern int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
extern struct lock_class_key irq_desc_lock_class;
extern void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr);
extern spinlock_t sparse_irq_lock;
+
+#ifdef CONFIG_SPARSE_IRQ
+/* irq_desc_ptrs allocated at boot time */
+extern struct irq_desc **irq_desc_ptrs;
+#else
+/* irq_desc_ptrs is a fixed size array */
extern struct irq_desc *irq_desc_ptrs[NR_IRQS];
+#endif
#ifdef CONFIG_PROC_FS
extern void register_irq_proc(unsigned int irq, struct irq_desc *desc);
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