From cd7eab44e9946c28d595abe3e9a43e945bc49141 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Wed, 19 Jan 2011 21:01:44 +0000 Subject: genirq: Add IRQ affinity notifiers When initiating I/O on a multiqueue and multi-IRQ device, we may want to select a queue for which the response will be handled on the same or a nearby CPU. This requires a reverse-map of IRQ affinity. Add a notification mechanism to support this. This is based closely on work by Thomas Gleixner . Signed-off-by: Ben Hutchings Cc: linux-net-drivers@solarflare.com Cc: Tom Herbert Cc: David Miller LKML-Reference: <1295470904.11126.84.camel@bwh-desktop> Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0caa59f747dd..0587c5ceaed8 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -134,6 +134,10 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) irq_set_thread_affinity(desc); } #endif + if (desc->affinity_notify) { + kref_get(&desc->affinity_notify->kref); + schedule_work(&desc->affinity_notify->work); + } desc->status |= IRQ_AFFINITY_SET; raw_spin_unlock_irqrestore(&desc->lock, flags); return 0; @@ -155,6 +159,79 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) } EXPORT_SYMBOL_GPL(irq_set_affinity_hint); +static void irq_affinity_notify(struct work_struct *work) +{ + struct irq_affinity_notify *notify = + container_of(work, struct irq_affinity_notify, work); + struct irq_desc *desc = irq_to_desc(notify->irq); + cpumask_var_t cpumask; + unsigned long flags; + + if (!desc) + goto out; + + if (!alloc_cpumask_var(&cpumask, GFP_KERNEL)) + goto out; + + raw_spin_lock_irqsave(&desc->lock, flags); +#ifdef CONFIG_GENERIC_PENDING_IRQ + if (desc->status & IRQ_MOVE_PENDING) + cpumask_copy(cpumask, desc->pending_mask); + else +#endif + cpumask_copy(cpumask, desc->affinity); + raw_spin_unlock_irqrestore(&desc->lock, flags); + + notify->notify(notify, cpumask); + + free_cpumask_var(cpumask); +out: + kref_put(¬ify->kref, notify->release); +} + +/** + * irq_set_affinity_notifier - control notification of IRQ affinity changes + * @irq: Interrupt for which to enable/disable notification + * @notify: Context for notification, or %NULL to disable + * notification. Function pointers must be initialised; + * the other fields will be initialised by this function. + * + * Must be called in process context. Notification may only be enabled + * after the IRQ is allocated and must be disabled before the IRQ is + * freed using free_irq(). + */ +int +irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) +{ + struct irq_desc *desc = irq_to_desc(irq); + struct irq_affinity_notify *old_notify; + unsigned long flags; + + /* The release function is promised process context */ + might_sleep(); + + if (!desc) + return -EINVAL; + + /* Complete initialisation of *notify */ + if (notify) { + notify->irq = irq; + kref_init(¬ify->kref); + INIT_WORK(¬ify->work, irq_affinity_notify); + } + + raw_spin_lock_irqsave(&desc->lock, flags); + old_notify = desc->affinity_notify; + desc->affinity_notify = notify; + raw_spin_unlock_irqrestore(&desc->lock, flags); + + if (old_notify) + kref_put(&old_notify->kref, old_notify->release); + + return 0; +} +EXPORT_SYMBOL_GPL(irq_set_affinity_notifier); + #ifndef CONFIG_AUTO_IRQ_AFFINITY /* * Generic version of the affinity autoselector. @@ -1004,6 +1081,11 @@ void free_irq(unsigned int irq, void *dev_id) if (!desc) return; +#ifdef CONFIG_SMP + if (WARN_ON(desc->affinity_notify)) + desc->affinity_notify = NULL; +#endif + chip_bus_lock(desc); kfree(__free_irq(irq, dev_id)); chip_bus_sync_unlock(desc); -- cgit v1.2.3