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irq_work: Add generic hardirq context callbacks

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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>
This commit is contained in:
Peter Zijlstra
2010-10-14 14:01:34 +08:00
committed by Ingo Molnar
parent 8e5fc1a732
commit e360adbe29
39 changed files with 311 additions and 242 deletions
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11
include/linux/perf_event.h
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@ -486,6 +486,7 @@ struct perf_guest_info_callbacks {
#include <linux/workqueue.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/irq_work.h>
#include <asm/atomic.h>
#include <asm/local.h>
@ -672,11 +673,6 @@ struct perf_buffer {
void *data_pages[0];
};
struct perf_pending_entry {
struct perf_pending_entry *next;
void (*func)(struct perf_pending_entry *);
};
struct perf_sample_data;
typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
@ -784,7 +780,7 @@ struct perf_event {
int pending_wakeup;
int pending_kill;
int pending_disable;
struct perf_pending_entry pending;
struct irq_work pending;
atomic_t event_limit;
@ -898,8 +894,6 @@ extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
extern void perf_event_delayed_put(struct task_struct *task);
extern void set_perf_event_pending(void);
extern void perf_event_do_pending(void);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
@ -1078,7 +1072,6 @@ static inline int perf_event_init_task(struct task_struct *child) { return 0; }
static inline void perf_event_exit_task(struct task_struct *child) { }
static inline void perf_event_free_task(struct task_struct *task) { }
static inline void perf_event_delayed_put(struct task_struct *task) { }
static inline void perf_event_do_pending(void) { }
static inline void perf_event_print_debug(void) { }
static inline int perf_event_task_disable(void) { return -EINVAL; }
static inline int perf_event_task_enable(void) { return -EINVAL; }