[PATCH] irq.h remove padding from irq_desc on 64bits

From: Richard Kennedy
Date: Sun Nov 23 2008 - 09:52:18 EST


struct irq_desc : reorder to remove padding on 64bits

shrinks irq_desc to 128 bytes which saves data space & cache lines

On a generic x86_64/SMP build this reduces the reported data size by
64k.

Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>

----
This patch is against 2.628-rc6, built & tested on AMD 64x2 desktop.

regards
Richard


diff --git a/include/linux/irq.h b/include/linux/irq.h
index d058c57..838a977 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -142,8 +142,8 @@ struct irq_chip {
* @depth: disable-depth, for nested irq_disable() calls
* @wake_depth: enable depth, for multiple set_irq_wake() callers
* @irq_count: stats field to detect stalled irqs
- * @irqs_unhandled: stats field for spurious unhandled interrupts
* @last_unhandled: aging timer for unhandled count
+ * @irqs_unhandled: stats field for spurious unhandled interrupts
* @lock: locking for SMP
* @affinity: IRQ affinity on SMP
* @cpu: cpu index useful for balancing
@@ -165,8 +165,8 @@ struct irq_desc {
unsigned int depth; /* nested irq disables */
unsigned int wake_depth; /* nested wake enables */
unsigned int irq_count; /* For detecting broken IRQs */
- unsigned int irqs_unhandled;
unsigned long last_unhandled; /* Aging timer for unhandled count */
+ unsigned int irqs_unhandled;
spinlock_t lock;
#ifdef CONFIG_SMP
cpumask_t affinity;


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