lkml.org 
[lkml]   [2008]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] x86_64: resize NR_IRQS for large machines
Subject: [PATCH] x86_64: resize NR_IRQS for large machines

From: Alan Mayer <ajm@sgi.com>

On machines with very large numbers of cpus, tables that are dimensioned
by NR_IRQS get very large, especially the irq_desc table. They are also
very sparsely used. When the cpu count is > MAX_IO_APICS, use MAX_IO_APICS
to set NR_IRQS, otherwise use NR_CPUS.

Signed-off-by: Alan Mayer <ajm@sgi.com>

Reviewed-by: Christoph Lameter <clameter@sgi.com>

---

Index: v2.6.25-rc6/include/asm-x86/irq_64.h
===================================================================
--- v2.6.25-rc6.orig/include/asm-x86/irq_64.h 2008-03-19 16:52:52.000000000 -0500
+++ v2.6.25-rc6/include/asm-x86/irq_64.h 2008-03-20 16:46:51.000000000 -0500
@@ -10,6 +10,10 @@
* <tomsoft@informatik.tu-chemnitz.de>
*/

+#if !defined(MAX_IO_APICS)
+#include <asm/apicdef.h>
+#endif
+
#define TIMER_IRQ 0

/*
@@ -31,7 +35,11 @@

#define FIRST_SYSTEM_VECTOR 0xef /* duplicated in hw_irq.h */

-#define NR_IRQS (NR_VECTORS + (32 *NR_CPUS))
+#if NR_CPUS < MAX_IO_APICS
+#define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
+#else
+#define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))
+#endif
#define NR_IRQ_VECTORS NR_IRQS

static __inline__ int irq_canonicalize(int irq)
Index: v2.6.25-rc6/include/linux/kernel_stat.h
===================================================================
--- v2.6.25-rc6.orig/include/linux/kernel_stat.h 2008-03-19 16:53:00.000000000 -0500
+++ v2.6.25-rc6/include/linux/kernel_stat.h 2008-03-20 11:12:27.000000000 -0500
@@ -1,11 +1,11 @@
#ifndef _LINUX_KERNEL_STAT_H
#define _LINUX_KERNEL_STAT_H

-#include <asm/irq.h>
#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/percpu.h>
#include <linux/cpumask.h>
+#include <asm/irq.h>
#include <asm/cputime.h>

/*


\
 
 \ /
  Last update: 2008-03-24 15:33    [W:0.059 / U:0.204 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site