Provide a new helper that help full dynticks CPUs to prevent from stopping their tick in case there are events in the local rotation list.
This way we make sure that perf_event_task_tick() is serviced on demand. Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Chris Metcalf <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Geoff Levand <[email protected]> Cc: Gilad Ben Yossef <[email protected]> Cc: Hakan Akkan <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Kevin Hilman <[email protected]> Cc: Li Zhong <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Paul Gortmaker <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Jiri Olsa <[email protected]> --- include/linux/perf_event.h | 6 ++++++ kernel/events/core.c | 10 ++++++++++ 2 files changed, 16 insertions(+), 0 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index e47ee46..0140830 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -799,6 +799,12 @@ static inline int __perf_event_disable(void *info) { return -1; } static inline void perf_event_task_tick(void) { } #endif +#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_NO_HZ_FULL) +extern bool perf_event_can_stop_tick(void); +#else +static inline bool perf_event_can_stop_tick(void) { return true; } +#endif + #define perf_output_put(handle, x) perf_output_copy((handle), &(x), sizeof(x)) /* diff --git a/kernel/events/core.c b/kernel/events/core.c index 75b58bb..ddb993b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2560,6 +2560,16 @@ done: list_del_init(&cpuctx->rotation_list); } +#ifdef CONFIG_NO_HZ_FULL +bool perf_event_can_stop_tick(void) +{ + if (list_empty(&__get_cpu_var(rotation_list))) + return true; + else + return false; +} +#endif + void perf_event_task_tick(void) { struct list_head *head = &__get_cpu_var(rotation_list); -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
