From b5faba21a6805c33b40e258d36f57997ee1de131 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 23 Feb 2011 23:52:13 +0000 Subject: genirq: Prepare the handling of shared oneshot interrupts For level type interrupts we need to track how many threads are on flight to avoid useless interrupt storms when not all thread handlers have finished yet. Keep track of the woken threads and only unmask when there are no more threads in flight. Yes, I'm lazy and using a bitfield. But not only because I'm lazy, the main reason is that it's way simpler than using a refcount. A refcount based solution would need to keep track of various things like crashing the irq thread, spurious interrupts coming in, disables/enables, free_irq() and some more. The bitfield keeps the tracking simple and makes things just work. It's also nicely confined to the thread code pathes and does not require additional checks all over the place. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra LKML-Reference: <20110223234956.388095876@linutronix.de> --- include/linux/interrupt.h | 2 ++ include/linux/irqdesc.h | 2 ++ 2 files changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 8da6643..e116fef 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -99,6 +99,7 @@ typedef irqreturn_t (*irq_handler_t)(int, void *); * @thread_fn: interupt handler function for threaded interrupts * @thread: thread pointer for threaded interrupts * @thread_flags: flags related to @thread + * @thread_mask: bitmask for keeping track of @thread activity */ struct irqaction { irq_handler_t handler; @@ -109,6 +110,7 @@ struct irqaction { irq_handler_t thread_fn; struct task_struct *thread; unsigned long thread_flags; + unsigned long thread_mask; const char *name; struct proc_dir_entry *dir; } ____cacheline_internodealigned_in_smp; diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h index 2f87d64..9eb9cd31 100644 --- a/include/linux/irqdesc.h +++ b/include/linux/irqdesc.h @@ -28,6 +28,7 @@ struct timer_rand_state; * @lock: locking for SMP * @affinity_notify: context for notification of affinity changes * @pending_mask: pending rebalanced interrupts + * @threads_oneshot: bitfield to handle shared oneshot threads * @threads_active: number of irqaction threads currently running * @wait_for_threads: wait queue for sync_irq to wait for threaded handlers * @dir: /proc/irq/ procfs entry @@ -86,6 +87,7 @@ struct irq_desc { cpumask_var_t pending_mask; #endif #endif + unsigned long threads_oneshot; atomic_t threads_active; wait_queue_head_t wait_for_threads; #ifdef CONFIG_PROC_FS -- cgit v1.1