unity-fallback-mount is perming inotify_watch_add every 4 seconds on the same files

[Colin Ian King]

unity-fallback-mount is polling away doing inotify_watch_add on the same paths every 4 seconds:

  PID Process Rate/Sec File
 30142 unity-fallback-mount 0.250 /usr/local/share/applications
 30142 unity-fallback-mount 0.250 /usr/share/ubuntu/applications

This is most probably wasted and unnecessary polling that is keeping the machine from keeping in deep sleep states (e.g. keeping it out of idle). Are these absolutely necessary?

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity-settings-daemon 14.04.0+14.04.20140402-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-21.43-generic 3.13.8
Uname: Linux 3.13.0-21-generic x86_64
ApportVersion: 2.14-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Apr 3 18:49:31 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-03-25 (9 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140323)
SourcePackage: unity-settings-daemon
UpgradeStatus: No upgrade log present (probably fresh install)
upstart.unity-settings-daemon.log: (unity-settings-daemon:2243): color-plugin-WARNING **: failed to connect to device: Failed to connect to missing device /org/freedesktop/ColorManager/devices/cups_Brother_HL_2170W_series

[Sebastien Bacher (seb128)]

Thank you for your bug report, I can't confirm that from stracing the binary here. Does it happen after login for you?

The directories listed suggest that something is putting a monitor on the XDG_DATA_DIRS directories, it's likely some gio API watching for new .desktop/applications to be installed.

Note that all those "things poll every 4 seconds on the same paths" issues are because inotify limitations, the kernel doesn't allow monitoring a non existant directory (e.g to get an event if the directory gets created and only start monitoring the content then). If we really want to stop having such problems we should look at fixing/improving the kernel

[Sebastien Bacher (seb128)]

The issue is likely similar to bug #1296233 and due to g_app_info apis