From 879aa24d6394aa04b690a600a41ff500441ad384 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 26 Nov 2010 06:47:28 -0300 Subject: [media] V4L: improve the BKL replacement heuristic The BKL replacement mutex had some serious performance side-effects on V4L drivers. It is replaced by a better heuristic that works around the worst of the side-effects. Read the v4l2-dev.c comments for the whole sorry story. This is a temporary measure only until we can convert all v4l drivers to use unlocked_ioctl. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- include/media/v4l2-device.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/media') diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h index 6648036b728d..b16f307d471a 100644 --- a/include/media/v4l2-device.h +++ b/include/media/v4l2-device.h @@ -51,6 +51,8 @@ struct v4l2_device { unsigned int notification, void *arg); /* The control handler. May be NULL. */ struct v4l2_ctrl_handler *ctrl_handler; + /* BKL replacement mutex. Temporary solution only. */ + struct mutex ioctl_lock; }; /* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev. -- cgit v1.2.3