Rather than directly executing mdevctl from the udev event thread when
we determine that we need to re-query, schedule the mdevctl thread to
run. This also helps to coalesce multiple back-to-back updates into a
single one when there are multiple updates in a row or at startup when a
host has a very large number of mdevs.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
---
 src/node_device/node_device_udev.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c
index 9ba550dbc1..da63d326a1 100644
--- a/src/node_device/node_device_udev.c
+++ b/src/node_device/node_device_udev.c
@@ -1443,6 +1443,9 @@ udevGetDeviceDetails(struct udev_device *device,
 }
 
 
+static void scheduleMdevctlUpdate(udevEventData *data, bool force);
+
+
 static int
 udevRemoveOneDeviceSysPath(const char *path)
 {
@@ -1475,8 +1478,7 @@ udevRemoveOneDeviceSysPath(const char *path)
     virNodeDeviceObjEndAPI(&obj);
 
     /* cannot check for mdev_types since they have already been removed */
-    if (nodeDeviceUpdateMediatedDevices() < 0)
-        VIR_WARN("mdevctl failed to update mediated devices");
+    scheduleMdevctlUpdate(driver->privateData, false);
 
     virObjectEventStateQueue(driver->nodeDeviceEventState, event);
     return 0;
@@ -1604,8 +1606,8 @@ udevAddOneDevice(struct udev_device *device)
     has_mdev_types = virNodeDeviceObjHasCap(obj, VIR_NODE_DEV_CAP_MDEV_TYPES);
     virNodeDeviceObjEndAPI(&obj);
 
-    if (has_mdev_types && nodeDeviceUpdateMediatedDevices() < 0)
-        VIR_WARN("mdevctl failed to update mediated devices");
+    if (has_mdev_types)
+        scheduleMdevctlUpdate(driver->privateData, false);
 
     ret = 0;
 
@@ -1767,8 +1769,7 @@ udevHandleOneDevice(struct udev_device *device)
         if (ret == 0 &&
             udevGetDeviceType(device, &dev_cap_type) == 0 &&
             dev_cap_type == VIR_NODE_DEV_CAP_MDEV)
-            if (nodeDeviceUpdateMediatedDevices() < 0)
-                VIR_WARN("mdevctl failed to update mediated devices");
+            scheduleMdevctlUpdate(driver->privateData, false);
         return ret;
     }
 
-- 
2.41.0

On 7/6/23 9:44 PM, Jonathon Jongsma wrote:
> Rather than directly executing mdevctl from the udev event thread when
> we determine that we need to re-query, schedule the mdevctl thread to
> run. This also helps to coalesce multiple back-to-back updates into a
> single one when there are multiple updates in a row or at startup when a
> host has a very large number of mdevs.
> 
> Signed-off-by: Jonathon Jongsma<jjongsma@redhat.com>
> ---
>   src/node_device/node_device_udev.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)

LGTM and works for vfio-ap mdevs (therefore for all other types as well).
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>

-- 
Mit freundlichen Grüßen/Kind regards
    Boris Fiuczynski

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