• Lightdm spawns unnecessary processes after locking the screen and logging back in.


    Hi,
    I have noticed that after every time I lock my laptop and log back in (or log out and then in), the RAM usage increases with around 100 MB. The reason for this seems to be that lightdm keeps spawning processes on each lock/relogin and does not kill them properly after a sucessfull login. In the attached screenshot, you can see many WebKitWebProcess and webkit2-greater processes and the RAM usage has reached 1300 MB, only from logging in/out and locking the computer and logging back in.

    I saw a couple of threads elsewhere about zombie processes spawned by lightdm and I wonder if this is something that is happening to anyone else using Antergos or if it is unique to my system. It should be easy to test, just lock your screen, log back in and see if the RAM usage has increased with around 100 MB.

    I currently using GDM instead of lightdm as a workaround. I also tested sddm and it worked fine as well, only lightdm seems to have this problem.
    0_1452554355617_Screenshot from 2015-12-28 18-24-42.png

  • Can confirm they are created and not killed, though it seems to take some time before they really start eating resources.

    0_1452742329870_Screenshot from 2016-01-13 20-29-14.png

  • Thanks for confirming @Dorothy_Ann .

    I found a discussion on this issue here and here. Basically, the lightdm greeter does not close when receiving SIGTERM signal. This problem has a patch in the AUR and is also supposed to be fixed in the latest version of the lightdm-gtk-greeter. However, there is no fix for webkit2 yet it seems. I confirmed that the gtk-greeter does kill these processes correctly, but I had problems with the screen locker using that greeter.

    This problem is quite severe to me as I have a laptop and lock it many times everyday, so I would need to kill processes manually all the time. Instead, I switched to gdm as the login manager, which uses about 100MB RAM out of the box, but has no problems with accumulating RAM usage and also fixes the issues I had with the lock screen not working.

  • Only to comment here, but 1300 MB is insane.
    Lightdm should be sleeping post boot.
    I wonder if locking the memory might help.
    In the lightdm.conf file, uncomment

    [LightDM]
    lock-memory=false
    

    Go to /etc/lightdm/lightdm.conf and uncomment and set to false .
    Check with top or htop
    I wonder if even toggling between the 2 may help. Can you check?

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