From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756993AbZALTyW (ORCPT ); Mon, 12 Jan 2009 14:54:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753265AbZALTyN (ORCPT ); Mon, 12 Jan 2009 14:54:13 -0500 Received: from hera.kernel.org ([140.211.167.34]:46365 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752744AbZALTyN (ORCPT ); Mon, 12 Jan 2009 14:54:13 -0500 Message-ID: <496B9FC3.7080306@kernel.org> Date: Mon, 12 Jan 2009 11:53:39 -0800 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner CC: Mike Travis , "linux-kernel@vger.kernel.org" Subject: [PATCH] x86: arch_probe_nr_irqs References: <496AD835.6000509@kernel.org> <20090112091952.GI26750@elte.hu> <20090112092613.GA1822@elte.hu> In-Reply-To: <20090112092613.GA1822@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Impact: save RAM with large NR_CPUS, get smaller nr_irqs Signed-off-by: Yinghai Lu --- arch/x86/include/asm/irq_vectors.h | 7 ++----- arch/x86/kernel/io_apic.c | 16 ++++++++++++++++ include/linux/interrupt.h | 1 + kernel/irq/handle.c | 9 ++------- kernel/softirq.c | 5 +++++ 5 files changed, 26 insertions(+), 12 deletions(-) Index: linux-2.6/arch/x86/include/asm/irq_vectors.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/irq_vectors.h +++ linux-2.6/arch/x86/include/asm/irq_vectors.h @@ -120,14 +120,11 @@ # endif #else -/* defined as a macro so nr_irqs = max_nr_irqs(nr_cpu_ids) can be used */ -# define max_nr_irqs(nr_cpus) \ - ((8 * nr_cpus) > (32 * MAX_IO_APICS) ? \ +# define NR_IRQS \ + ((8 * NR_CPUS) > (32 * MAX_IO_APICS) ? \ (NR_VECTORS + (8 * NR_CPUS)) : \ (NR_VECTORS + (32 * MAX_IO_APICS))) \ -# define NR_IRQS max_nr_irqs(NR_CPUS) - #endif #elif defined(CONFIG_X86_VOYAGER) Index: linux-2.6/arch/x86/kernel/io_apic.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/io_apic.c +++ linux-2.6/arch/x86/kernel/io_apic.c @@ -3851,6 +3851,22 @@ void __init probe_nr_irqs_gsi(void) nr_irqs_gsi = nr; } +#ifdef CONFIG_SPARSE_IRQ +int __init arch_probe_nr_irqs(void) +{ + int nr; + + nr = ((8 * nr_cpu_ids) > (32 * nr_ioapics) ? + (NR_VECTORS + (8 * nr_cpu_ids)) : + (NR_VECTORS + (32 * nr_ioapics))); + + if (nr < nr_irqs && nr > nr_irqs_gsi) + nr_irqs = nr; + + return 0; +} +#endif + /* -------------------------------------------------------------------------- ACPI-based IOAPIC Configuration -------------------------------------------------------------------------- */ Index: linux-2.6/include/linux/interrupt.h =================================================================== --- linux-2.6.orig/include/linux/interrupt.h +++ linux-2.6/include/linux/interrupt.h @@ -481,6 +481,7 @@ int show_interrupts(struct seq_file *p, struct irq_desc; extern int early_irq_init(void); +extern int arch_probe_nr_irqs(void); extern int arch_early_irq_init(void); extern int arch_init_chip_data(struct irq_desc *desc, int cpu); Index: linux-2.6/kernel/irq/handle.c =================================================================== --- linux-2.6.orig/kernel/irq/handle.c +++ linux-2.6/kernel/irq/handle.c @@ -59,10 +59,6 @@ EXPORT_SYMBOL_GPL(nr_irqs); #ifdef CONFIG_SPARSE_IRQ -#ifndef max_nr_irqs -#define max_nr_irqs(nr_cpus) NR_IRQS -#endif - static struct irq_desc irq_desc_init = { .irq = -1, .status = IRQ_DISABLED, @@ -137,9 +133,8 @@ int __init early_irq_init(void) int legacy_count; int i; - /* initialize nr_irqs based on nr_cpu_ids */ - nr_irqs = max_nr_irqs(nr_cpu_ids); - + /* initialize nr_irqs based on nr_cpu_ids */ + arch_probe_nr_irqs(); printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs); desc = irq_desc_legacy; Index: linux-2.6/kernel/softirq.c =================================================================== --- linux-2.6.orig/kernel/softirq.c +++ linux-2.6/kernel/softirq.c @@ -806,6 +806,11 @@ int __init __weak early_irq_init(void) return 0; } +int __init __weak arch_probe_nr_irqs(void) +{ + return 0; +} + int __init __weak arch_early_irq_init(void) { return 0;