Make it possible to disable an event but continue to receive "tracking" events i.e. continue to receive mmap, comm, task events. The flag is updated by both PERF_EVENT_IOC_DISABLE and PERF_EVENT_IOC_ENABLE. The flag is cleared by prctl PR_TASK_PERF_EVENTS_DISABLE.
Signed-off-by: Adrian Hunter <[email protected]> --- include/linux/perf_event.h | 1 + include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 21 +++++++++++++++++++-- 3 files changed, 21 insertions(+), 2 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 50b3efd..789eeeb 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -436,6 +436,7 @@ struct perf_event { struct perf_cgroup *cgrp; /* cgroup event is attach to */ int cgrp_defer_enabled; #endif + int keep_tracking; #endif /* CONFIG_PERF_EVENTS */ }; diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 663be3f..7b4ecfb 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -324,6 +324,7 @@ struct perf_event_attr { enum perf_event_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, + PERF_IOC_KEEP_TRACKING = 1U << 1, }; /* diff --git a/kernel/events/core.c b/kernel/events/core.c index 1db3af9..0c1fbe9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3495,6 +3495,16 @@ static inline int perf_fget_light(int fd, struct fd *p) return 0; } +static void perf_event_keep_tracking(struct perf_event *event, u32 flags) +{ + int keep_tracking = !!(flags & PERF_IOC_KEEP_TRACKING); + + if (flags & PERF_IOC_FLAG_GROUP) + event->group_leader->keep_tracking = keep_tracking; + else + event->keep_tracking = keep_tracking; +} + static int perf_event_set_output(struct perf_event *event, struct perf_event *output_event); static int perf_event_set_filter(struct perf_event *event, void __user *arg); @@ -3510,6 +3520,7 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) func = perf_event_enable; break; case PERF_EVENT_IOC_DISABLE: + perf_event_keep_tracking(event, flags); func = perf_event_disable; break; case PERF_EVENT_IOC_RESET: @@ -3552,6 +3563,9 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) else perf_event_for_each_child(event, func); + if (cmd == PERF_EVENT_IOC_ENABLE) + perf_event_keep_tracking(event, flags); + return 0; } @@ -3572,8 +3586,10 @@ int perf_event_task_disable(void) struct perf_event *event; mutex_lock(¤t->perf_event_mutex); - list_for_each_entry(event, ¤t->perf_event_list, owner_entry) + list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { perf_event_for_each_child(event, perf_event_disable); + event->keep_tracking = 0; + } mutex_unlock(¤t->perf_event_mutex); return 0; @@ -4670,7 +4686,8 @@ perf_event_aux_ctx(struct perf_event_context *ctx, struct perf_event *event; list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { - if (event->state < PERF_EVENT_STATE_INACTIVE) + if (event->state < PERF_EVENT_STATE_INACTIVE && + !event->keep_tracking) continue; if (!event_filter_match(event)) continue; -- 1.7.11.7 -- 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/
