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linux-pinenote/include/linux/irq_work.h

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irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
#ifndef _LINUX_IRQ_WORK_H
#define _LINUX_IRQ_WORK_H
irq_work: Use llist in the struct irq_work logic Use llist in irq_work instead of the lock-less linked list implementation in irq_work to avoid the code duplication. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-08 14:00:46 +08:00
#include <linux/llist.h>
irq_work: Make self-IPIs optable On irq work initialization, let the user choose to define it as "lazy" or not. "Lazy" means that we don't want to send an IPI (provided the arch can anyway) when we enqueue this work but we rather prefer to wait for the next timer tick to execute our work if possible. This is going to be a benefit for non-urgent enqueuers (like printk in the future) that may prefer not to raise an IPI storm in case of frequent enqueuing on short periods of time. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-10-19 16:43:41 -04:00
/*
* An entry can be in one of four states:
*
* free NULL, 0 -> {claimed} : free to be used
* claimed NULL, 3 -> {pending} : claimed to be enqueued
* pending next, 3 -> {busy} : queued, pending callback
* busy NULL, 2 -> {free, claimed} : callback in progress, can be claimed
*/
#define IRQ_WORK_PENDING 1UL
#define IRQ_WORK_BUSY 2UL
#define IRQ_WORK_FLAGS 3UL
#define IRQ_WORK_LAZY 4UL /* Doesn't want IPI, wait for tick */
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
struct irq_work {
irq_work: Use llist in the struct irq_work logic Use llist in irq_work instead of the lock-less linked list implementation in irq_work to avoid the code duplication. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-08 14:00:46 +08:00
unsigned long flags;
struct llist_node llnode;
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
void (*func)(struct irq_work *);
};
static inline
irq_work: Use llist in the struct irq_work logic Use llist in irq_work instead of the lock-less linked list implementation in irq_work to avoid the code duplication. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-08 14:00:46 +08:00
void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
{
irq_work: Use llist in the struct irq_work logic Use llist in irq_work instead of the lock-less linked list implementation in irq_work to avoid the code duplication. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-08 14:00:46 +08:00
work->flags = 0;
work->func = func;
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
}
perf/x86: Push the duration-logging printk() to IRQ context Calling printk() from NMI context is bad (TM), so move it to IRQ context. This also avoids the problem where the printk() time is measured by the generic NMI duration goo and triggers a second warning. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Don Zickus <dzickus@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Link: http://lkml.kernel.org/n/tip-75dv35xf6dhhmeb7nq6fua31@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-02-03 18:11:08 +01:00
#define DEFINE_IRQ_WORK(name, _f) struct irq_work name = { .func = (_f), }
perf/x86: Warn to early_printk() in case irq_work is too slow On Mon, Feb 10, 2014 at 08:45:16AM -0800, Dave Hansen wrote: > The reason I coded this up was that NMIs were firing off so fast that > nothing else was getting a chance to run. With this patch, at least the > printk() would come out and I'd have some idea what was going on. It will start spewing to early_printk() (which is a lot nicer to use from NMI context too) when it fails to queue the IRQ-work because its already enqueued. It does have the false-positive for when two CPUs trigger the warn concurrently, but that should be rare and some extra clutter on the early printk shouldn't be a problem. Cc: hpa@zytor.com Cc: tglx@linutronix.de Cc: dzickus@redhat.com Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: mingo@kernel.org Fixes: 6a02ad66b2c4 ("perf/x86: Push the duration-logging printk() to IRQ context") Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140211150116.GO27965@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-11 16:01:16 +01:00
bool irq_work_queue(struct irq_work *work);
irq_work: Implement remote queueing irq work currently only supports local callbacks. However its code is mostly ready to run remote callbacks and we have some potential user. The full nohz subsystem currently open codes its own remote irq work on top of the scheduler ipi when it wants a CPU to reevaluate its next tick. However this ad hoc solution bloats the scheduler IPI. Lets just extend the irq work subsystem to support remote queuing on top of the generic SMP IPI to handle this kind of user. This shouldn't add noticeable overhead. Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-05-08 01:37:48 +02:00
#ifdef CONFIG_SMP
bool irq_work_queue_on(struct irq_work *work, int cpu);
#endif
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
void irq_work_run(void);
irq_work: Force raised irq work to run on irq work interrupt The nohz full kick, which restarts the tick when any resource depend on it, can't be executed anywhere given the operation it does on timers. If it is called from the scheduler or timers code, chances are that we run into a deadlock. This is why we run the nohz full kick from an irq work. That way we make sure that the kick runs on a virgin context. However if that's the case when irq work runs in its own dedicated self-ipi, things are different for the big bunch of archs that don't support the self triggered way. In order to support them, irq works are also handled by the timer interrupt as fallback. Now when irq works run on the timer interrupt, the context isn't blank. More precisely, they can run in the context of the hrtimer that runs the tick. But the nohz kick cancels and restarts this hrtimer and cancelling an hrtimer from itself isn't allowed. This is why we run in an endless loop: Kernel panic - not syncing: Watchdog detected hard LOCKUP on cpu 2 CPU: 2 PID: 7538 Comm: kworker/u8:8 Not tainted 3.16.0+ #34 Workqueue: btrfs-endio-write normal_work_helper [btrfs] ffff880244c06c88 000000001b486fe1 ffff880244c06bf0 ffffffff8a7f1e37 ffffffff8ac52a18 ffff880244c06c78 ffffffff8a7ef928 0000000000000010 ffff880244c06c88 ffff880244c06c20 000000001b486fe1 0000000000000000 Call Trace: <NMI[<ffffffff8a7f1e37>] dump_stack+0x4e/0x7a [<ffffffff8a7ef928>] panic+0xd4/0x207 [<ffffffff8a1450e8>] watchdog_overflow_callback+0x118/0x120 [<ffffffff8a186b0e>] __perf_event_overflow+0xae/0x350 [<ffffffff8a184f80>] ? perf_event_task_disable+0xa0/0xa0 [<ffffffff8a01a4cf>] ? x86_perf_event_set_period+0xbf/0x150 [<ffffffff8a187934>] perf_event_overflow+0x14/0x20 [<ffffffff8a020386>] intel_pmu_handle_irq+0x206/0x410 [<ffffffff8a01937b>] perf_event_nmi_handler+0x2b/0x50 [<ffffffff8a007b72>] nmi_handle+0xd2/0x390 [<ffffffff8a007aa5>] ? nmi_handle+0x5/0x390 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a008062>] default_do_nmi+0x72/0x1c0 [<ffffffff8a008268>] do_nmi+0xb8/0x100 [<ffffffff8a7ff66a>] end_repeat_nmi+0x1e/0x2e [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 [<ffffffff8a0cb7f8>] ? match_held_lock+0x8/0x1b0 <<EOE><IRQ[<ffffffff8a0ccd2f>] lock_acquired+0xaf/0x450 [<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a7fc678>] _raw_spin_lock_irqsave+0x78/0x90 [<ffffffff8a0f74c5>] ? lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a0f74c5>] lock_hrtimer_base.isra.20+0x25/0x50 [<ffffffff8a0f7723>] hrtimer_try_to_cancel+0x33/0x1e0 [<ffffffff8a0f78ea>] hrtimer_cancel+0x1a/0x30 [<ffffffff8a109237>] tick_nohz_restart+0x17/0x90 [<ffffffff8a10a213>] __tick_nohz_full_check+0xc3/0x100 [<ffffffff8a10a25e>] nohz_full_kick_work_func+0xe/0x10 [<ffffffff8a17c884>] irq_work_run_list+0x44/0x70 [<ffffffff8a17c8da>] irq_work_run+0x2a/0x50 [<ffffffff8a0f700b>] update_process_times+0x5b/0x70 [<ffffffff8a109005>] tick_sched_handle.isra.21+0x25/0x60 [<ffffffff8a109b81>] tick_sched_timer+0x41/0x60 [<ffffffff8a0f7aa2>] __run_hrtimer+0x72/0x470 [<ffffffff8a109b40>] ? tick_sched_do_timer+0xb0/0xb0 [<ffffffff8a0f8707>] hrtimer_interrupt+0x117/0x270 [<ffffffff8a034357>] local_apic_timer_interrupt+0x37/0x60 [<ffffffff8a80010f>] smp_apic_timer_interrupt+0x3f/0x50 [<ffffffff8a7fe52f>] apic_timer_interrupt+0x6f/0x80 To fix this we force non-lazy irq works to run on irq work self-IPIs when available. That ability of the arch to trigger irq work self IPIs is available with arch_irq_work_has_interrupt(). Reported-by: Catalin Iacob <iacobcatalin@gmail.com> Reported-by: Dave Jones <davej@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-08-16 18:37:19 +02:00
void irq_work_tick(void);
irq_work: Use llist in the struct irq_work logic Use llist in irq_work instead of the lock-less linked list implementation in irq_work to avoid the code duplication. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-6-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-08 14:00:46 +08:00
void irq_work_sync(struct irq_work *work);
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
irq_work: Don't stop the tick with pending works Don't stop the tick if we have pending irq works on the queue, otherwise if the arch can't raise self-IPIs, we may not find an opportunity to execute the pending works for a while. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-07 21:03:07 +01:00
#ifdef CONFIG_IRQ_WORK
irq_work: Introduce arch_irq_work_has_interrupt() The nohz full code needs irq work to trigger its own interrupt so that the subsystem can work even when the tick is stopped. Lets introduce arch_irq_work_has_interrupt() that archs can override to tell about their support for this ability. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-09-06 15:43:02 +02:00
#include <asm/irq_work.h>
irq_work: Don't stop the tick with pending works Don't stop the tick if we have pending irq works on the queue, otherwise if the arch can't raise self-IPIs, we may not find an opportunity to execute the pending works for a while. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-07 21:03:07 +01:00
bool irq_work_needs_cpu(void);
#else
irq_work.h: fix warning when CONFIG_IRQ_WORK=n A randconfig caught repeated compiler warnings when CONFIG_IRQ_WORK=n due to the definition of a non-inline static function in <linux/irq_work.h>: include/linux/irq_work.h +40 : warning: 'irq_work_needs_cpu' defined but not used Make it inline to supress the warning. This is caused commit 00b42959106a ("irq_work: Don't stop the tick with pending works") merged in v3.9-rc1. Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-22 15:04:37 -07:00
static inline bool irq_work_needs_cpu(void) { return false; }
irq_work: Don't stop the tick with pending works Don't stop the tick if we have pending irq works on the queue, otherwise if the arch can't raise self-IPIs, we may not find an opportunity to execute the pending works for a while. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-07 21:03:07 +01:00
#endif
irq_work: Add generic hardirq context callbacks Provide a mechanism that allows running code in IRQ context. It is most useful for NMI code that needs to interact with the rest of the system -- like wakeup a task to drain buffers. Perf currently has such a mechanism, so extract that and provide it as a generic feature, independent of perf so that others may also benefit. The IRQ context callback is generated through self-IPIs where possible, or on architectures like powerpc the decrementer (the built-in timer facility) is set to generate an interrupt immediately. Architectures that don't have anything like this get to do with a callback from the timer tick. These architectures can call irq_work_run() at the tail of any IRQ handlers that might enqueue such work (like the perf IRQ handler) to avoid undue latencies in processing the work. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [ various fixes ] Signed-off-by: Huang Ying <ying.huang@intel.com> LKML-Reference: <1287036094.7768.291.camel@yhuang-dev> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-14 14:01:34 +08:00
#endif /* _LINUX_IRQ_WORK_H */
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