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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2010-10-14 02:01:34 -0400
committerIngo Molnar <mingo@elte.hu>2010-10-18 13:58:50 -0400
commite360adbe29241a0194e10e20595360dd7b98a2b3 (patch)
treeef5fa5f50a895096bfb25bc11b25949603158238 /kernel/timer.c
parent8e5fc1a7320baf6076391607515dceb61319b36a (diff)
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>
Diffstat (limited to 'kernel/timer.c')
-rw-r--r--kernel/timer.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index 97bf05baade7..68a9ae7679b7 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -37,7 +37,7 @@
37#include <linux/delay.h> 37#include <linux/delay.h>
38#include <linux/tick.h> 38#include <linux/tick.h>
39#include <linux/kallsyms.h> 39#include <linux/kallsyms.h>
40#include <linux/perf_event.h> 40#include <linux/irq_work.h>
41#include <linux/sched.h> 41#include <linux/sched.h>
42#include <linux/slab.h> 42#include <linux/slab.h>
43 43
@@ -1279,7 +1279,10 @@ void update_process_times(int user_tick)
1279 run_local_timers(); 1279 run_local_timers();
1280 rcu_check_callbacks(cpu, user_tick); 1280 rcu_check_callbacks(cpu, user_tick);
1281 printk_tick(); 1281 printk_tick();
1282 perf_event_do_pending(); 1282#ifdef CONFIG_IRQ_WORK
1283 if (in_irq())
1284 irq_work_run();
1285#endif
1283 scheduler_tick(); 1286 scheduler_tick();
1284 run_posix_cpu_timers(p); 1287 run_posix_cpu_timers(p);
1285} 1288}