As of now we don't get any notice for pinned events when it's failed to be scheduled and make it in an error state not try to schedule it again. That means we won't get any samples for the event.
It's possible we can detect it by reading the file, but usually we only monitor it via mmap-ed ring buffers. Let's poke the tasks waiting for poll(2) so that they can respond to the event. Signed-off-by: Namhyung Kim <[email protected]> --- include/linux/perf_event.h | 1 + kernel/events/core.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 9a38f579bc76..0b3b3e97243b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -733,6 +733,7 @@ struct perf_event { int pending_wakeup; int pending_kill; int pending_disable; + int pending_pin_error; struct irq_work pending; atomic_t event_limit; diff --git a/kernel/events/core.c b/kernel/events/core.c index 55d18791a72d..f8e9db30a573 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3675,6 +3675,8 @@ static int merge_sched_in(struct perf_event *event, void *data) if (event->attr.pinned) { perf_cgroup_event_disable(event, ctx); perf_event_set_state(event, PERF_EVENT_STATE_ERROR); + event->pending_pin_error = 1; + irq_work_queue(&event->pending); } *can_add_hw = 0; @@ -5288,6 +5290,9 @@ static __poll_t perf_poll(struct file *file, poll_table *wait) if (is_event_hup(event)) return events; + if (event->attr.pinned && event->state == PERF_EVENT_STATE_ERROR) + return EPOLLERR; + /* * Pin the event->rb by taking event->mmap_mutex; otherwise * perf_event_set_output() can swizzle our rb and make us miss wakeups. @@ -6333,6 +6338,11 @@ static void perf_pending_event(struct irq_work *entry) perf_event_wakeup(event); } + if (event->pending_pin_error) { + event->pending_pin_error = 0; + wake_up_all(&event->waitq); + } + if (rctx >= 0) perf_swevent_put_recursion_context(rctx); } -- 2.30.0.365.g02bc693789-goog
