From 18404756765c713a0be4eb1082920c04822ce588 Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Thu, 29 May 2008 11:02:52 -0700 Subject: genirq: Expose default irq affinity mask (take 3) Current IRQ affinity interface does not provide a way to set affinity for the IRQs that will be allocated/activated in the future. This patch creates /proc/irq/default_smp_affinity that lets users set default affinity mask for the newly allocated IRQs. Changing the default does not affect affinity masks for the currently active IRQs, they have to be changed explicitly. Updated based on Paul J's comments and added some more documentation. Signed-off-by: Max Krasnyansky Cc: pj@sgi.com Cc: a.p.zijlstra@chello.nl Cc: tglx@linutronix.de Cc: rdunlap@xenotime.net Cc: mingo@elte.hu Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 28 +++++++++++++++++++++++-- kernel/irq/proc.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 81 insertions(+), 6 deletions(-) (limited to 'kernel/irq') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 46d6611a33bb..469814e9b9ee 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -17,6 +17,8 @@ #ifdef CONFIG_SMP +cpumask_t irq_default_affinity = CPU_MASK_ALL; + /** * synchronize_irq - wait for pending IRQ handlers (on other CPUs) * @irq: interrupt number to wait for @@ -95,6 +97,27 @@ int irq_set_affinity(unsigned int irq, cpumask_t cpumask) return 0; } +#ifndef CONFIG_AUTO_IRQ_AFFINITY +/* + * Generic version of the affinity autoselector. + */ +int irq_select_affinity(unsigned int irq) +{ + cpumask_t mask; + + if (!irq_can_set_affinity(irq)) + return 0; + + cpus_and(mask, cpu_online_map, irq_default_affinity); + + irq_desc[irq].affinity = mask; + irq_desc[irq].chip->set_affinity(irq, mask); + + set_balance_irq_affinity(irq, mask); + return 0; +} +#endif + #endif /** @@ -382,6 +405,9 @@ int setup_irq(unsigned int irq, struct irqaction *new) } else /* Undo nested disables: */ desc->depth = 1; + + /* Set default affinity mask once everything is setup */ + irq_select_affinity(irq); } /* Reset broken irq detection when installing new handler */ desc->irq_count = 0; @@ -571,8 +597,6 @@ int request_irq(unsigned int irq, irq_handler_t handler, action->next = NULL; action->dev_id = dev_id; - select_smp_affinity(irq); - #ifdef CONFIG_DEBUG_SHIRQ if (irqflags & IRQF_SHARED) { /* diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index c2f2ccb0549a..6c6d35d68ee9 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -44,7 +44,7 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer, unsigned long count, void *data) { unsigned int irq = (int)(long)data, full_count = count, err; - cpumask_t new_value, tmp; + cpumask_t new_value; if (!irq_desc[irq].chip->set_affinity || no_irq_affinity || irq_balancing_disabled(irq)) @@ -62,17 +62,51 @@ static int irq_affinity_write_proc(struct file *file, const char __user *buffer, * way to make the system unusable accidentally :-) At least * one online CPU still has to be targeted. */ - cpus_and(tmp, new_value, cpu_online_map); - if (cpus_empty(tmp)) + if (!cpus_intersects(new_value, cpu_online_map)) /* Special case for empty set - allow the architecture code to set default SMP affinity. */ - return select_smp_affinity(irq) ? -EINVAL : full_count; + return irq_select_affinity(irq) ? -EINVAL : full_count; irq_set_affinity(irq, new_value); return full_count; } +static int default_affinity_read(char *page, char **start, off_t off, + int count, int *eof, void *data) +{ + int len = cpumask_scnprintf(page, count, irq_default_affinity); + if (count - len < 2) + return -EINVAL; + len += sprintf(page + len, "\n"); + return len; +} + +static int default_affinity_write(struct file *file, const char __user *buffer, + unsigned long count, void *data) +{ + unsigned int full_count = count, err; + cpumask_t new_value; + + err = cpumask_parse_user(buffer, count, new_value); + if (err) + return err; + + if (!is_affinity_mask_valid(new_value)) + return -EINVAL; + + /* + * Do not allow disabling IRQs completely - it's a too easy + * way to make the system unusable accidentally :-) At least + * one online CPU still has to be targeted. + */ + if (!cpus_intersects(new_value, cpu_online_map)) + return -EINVAL; + + irq_default_affinity = new_value; + + return full_count; +} #endif static int irq_spurious_read(char *page, char **start, off_t off, @@ -171,6 +205,21 @@ void unregister_handler_proc(unsigned int irq, struct irqaction *action) remove_proc_entry(action->dir->name, irq_desc[irq].dir); } +void register_default_affinity_proc(void) +{ +#ifdef CONFIG_SMP + struct proc_dir_entry *entry; + + /* create /proc/irq/default_smp_affinity */ + entry = create_proc_entry("default_smp_affinity", 0600, root_irq_dir); + if (entry) { + entry->data = NULL; + entry->read_proc = default_affinity_read; + entry->write_proc = default_affinity_write; + } +#endif +} + void init_irq_proc(void) { int i; @@ -180,6 +229,8 @@ void init_irq_proc(void) if (!root_irq_dir) return; + register_default_affinity_proc(); + /* * Create entries for all existing IRQs. */ -- cgit v1.2.3 From 48627d8d23c34106c1365563604739a50343edaf Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 10 Jul 2008 07:01:13 +0200 Subject: genirq: remove extraneous checks in manage.c In http://bugzilla.kernel.org/show_bug.cgi?id=9580 it was pointed out that the desc->chip checks are extraneous. In fact these are left overs from early development and can be removed safely. Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel/irq') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 469814e9b9ee..77a51be36010 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -377,7 +377,7 @@ int setup_irq(unsigned int irq, struct irqaction *new) /* Setup the type (level, edge polarity) if configured: */ if (new->flags & IRQF_TRIGGER_MASK) { - if (desc->chip && desc->chip->set_type) + if (desc->chip->set_type) desc->chip->set_type(irq, new->flags & IRQF_TRIGGER_MASK); else @@ -387,8 +387,7 @@ int setup_irq(unsigned int irq, struct irqaction *new) */ printk(KERN_WARNING "No IRQF_TRIGGER set_type " "function for IRQ %d (%s)\n", irq, - desc->chip ? desc->chip->name : - "unknown"); + desc->chip->name); } else compat_irq_chip_set_default_handler(desc); -- cgit v1.2.3