On Tue, Jun 13, 2017 at 05:03:42PM +0530, Naveen N. Rao wrote:
SNIP
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index b1c0b187acfe..e5810b1d74a4 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -345,7 +345,8 @@ struct perf_event_attr {
> context_switch : 1, /* context switch data */
> write_backward : 1, /* Write ring buffer from
> end to beginning */
> namespaces : 1, /* include namespaces data
> */
> - __reserved_1 : 35;
> + signal_on_wakeup : 1, /* send signal on wakeup
> */
> + __reserved_1 : 34;
>
> union {
> __u32 wakeup_events; /* wakeup every n events */
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 6c4e523dc1e2..73ad30e124e5 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7362,12 +7362,14 @@ static int __perf_event_overflow(struct perf_event
> *event,
> * events
> */
>
> - event->pending_kill = POLL_IN;
> - if (events && atomic_dec_and_test(&event->event_limit)) {
> - ret = 1;
> - event->pending_kill = POLL_HUP;
> + if (!event->attr.signal_on_wakeup) {
> + event->pending_kill = POLL_IN;
> + if (events && atomic_dec_and_test(&event->event_limit)) {
> + ret = 1;
> + event->pending_kill = POLL_HUP;
>
> - perf_event_disable_inatomic(event);
> + perf_event_disable_inatomic(event);
> + }
> }
>
> READ_ONCE(event->overflow_handler)(event, data, regs);
> diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
> index 2831480c63a2..4e7c728569a8 100644
> --- a/kernel/events/ring_buffer.c
> +++ b/kernel/events/ring_buffer.c
> @@ -21,6 +21,9 @@ static void perf_output_wakeup(struct perf_output_handle
> *handle)
> {
> atomic_set(&handle->rb->poll, POLLIN);
>
> + if (handle->event->attr.signal_on_wakeup)
> + handle->event->pending_kill = POLL_IN;
> +
since it's signal_on_wakeup, should we also send POLL_HUP for
perf_event_wakeup calls from perf_event_exit_event?
jirka
