[PATCH 2/5] vmbus: suppress uevents for hv_sock devices

From: kys
Date: Sun Sep 10 2017 - 02:10:47 EST

From: Dexuan Cui <decui@xxxxxxxxxxxxx>

hv_sock driver is automatically loaded when an application creates an
AF_VSOCK socket, so we don't really need to trigger uevents to the user
space udevd.

And hv_sock devices can appear and disappear frequency, e.g. 100 per
second, so triggering the udevents can cause a high cpu utilization of
udevd, e.g. 30% on a 2-cpu virtual machine. So let's suppress the
uevents to avoid this.

Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
drivers/hv/vmbus_drv.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 43160a2eafe0..2c147702ce08 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1174,6 +1174,8 @@ int vmbus_device_register(struct hv_device *child_device_obj)
child_device_obj->device.parent = &hv_acpi_dev->dev;
child_device_obj->device.release = vmbus_device_release;

+ if (is_hvsock_channel(child_device_obj->channel))
+ dev_set_uevent_suppress(&child_device_obj->device, 1);
* Register with the LDM. This will kick off the driver/device
* binding...which will eventually call vmbus_match() and vmbus_probe()