Some processes, such as systemd, are only polling for EPOLLERR|EPOLLHUP. As drm_file uses unkeyed wakeups, such a poll can receive many spurious wakeups from uninteresting events if, for example, the file description is subscribed to vblank events. This is the case with systemd, as it polls a file description from logind that is shared with the users' compositor.
Use keyed wakeups to allow the wakeup target to more efficiently discard these uninteresting events.
Signed-off-by: Kenny Levinsen kl@kl.wtf --- drivers/gpu/drm/drm_file.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index c4c704e01961..ec25b3d979d9 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -608,7 +608,8 @@ ssize_t drm_read(struct file *filp, char __user *buffer, file_priv->event_space -= length; list_add(&e->link, &file_priv->event_list); spin_unlock_irq(&dev->event_lock); - wake_up_interruptible(&file_priv->event_wait); + wake_up_interruptible_poll(&file_priv->event_wait, + EPOLLIN | EPOLLRDNORM); break; }
@@ -804,7 +805,8 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e) list_del(&e->pending_link); list_add_tail(&e->link, &e->file_priv->event_list); - wake_up_interruptible(&e->file_priv->event_wait); + wake_up_interruptible_poll(&e->file_priv->event_wait, + EPOLLIN | EPOLLRDNORM); } EXPORT_SYMBOL(drm_send_event_locked);