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 <tglx@linutronix.de>.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: linux-net-drivers@solarflare.com
Cc: Tom Herbert <therbert@google.com>
Cc: David Miller <davem@davemloft.net>
LKML-Reference: <1295470904.11126.84.camel@bwh-desktop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index c1a95b7..bfef56d 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -8,6 +8,7 @@
* For now it's included from <linux/irq.h>
*/
+struct irq_affinity_notify;
struct proc_dir_entry;
struct timer_rand_state;
/**
@@ -24,6 +25,7 @@
* @last_unhandled: aging timer for unhandled count
* @irqs_unhandled: stats field for spurious unhandled interrupts
* @lock: locking for SMP
+ * @affinity_notify: context for notification of affinity changes
* @pending_mask: pending rebalanced interrupts
* @threads_active: number of irqaction threads currently running
* @wait_for_threads: wait queue for sync_irq to wait for threaded handlers
@@ -70,6 +72,7 @@
raw_spinlock_t lock;
#ifdef CONFIG_SMP
const struct cpumask *affinity_hint;
+ struct irq_affinity_notify *affinity_notify;
#ifdef CONFIG_GENERIC_PENDING_IRQ
cpumask_var_t pending_mask;
#endif