device: don't emit PropetiesChanged needlessly

Functions called from device_setup_unit() already make sure that unit is
enqueued in case it is a new unit or properties exported on the bus have
changed.

This should prevent unnecessary DBus wakeups and associated DBus traffic
when device_setup_unit() was called while reparsing /proc/self/mountinfo
due to the mountinfo notifications. Note that we parse
/proc/self/mountinfo quite often on the busy systems (e.g. k8s container
hosts) but majority of the time mounts didn't change, only some mount
got added. Thus we don't need to generate PropertiesChanged for devices
associated with the mounts that didn't change.

Thanks to Renaud Métrich <rmetrich@redhat.com> for debugging the
problem and providing draft version of the patch.

(cherry picked from commit 2e129d5d6bd6bd8be4b5359e81a880cbf72a44b8)

Resolves: #1793533

diff --git a/src/core/device.c b/src/core/device.c
index 21fe3802bde57def4892f01a37b39ddceb6e8384..021c28dfbd52db6c117ed090a7fddb9fe95572ed 100644 (file)
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -549,9 +549,6 @@ static int device_setup_unit(Manager *m, struct udev_device *dev, const char *pa
         if (dev && device_is_bound_by_mounts(DEVICE(u), dev))
                 device_upgrade_mount_deps(u);
 
-        /* Note that this won't dispatch the load queue, the caller has to do that if needed and appropriate */
-        unit_add_to_dbus_queue(u);
-
         return 0;
 
 fail: