Plasmashell memory leak

[bschelst]

16Gb over here

[GreyGeek]

That probably explains why your memory use is greater!

[jpeg729]

I got home today to find plasmashell using 5.5Gb swap and 2.3Gb ram on Kubuntu 18.04. WHY?

Other threads suggest that certain widgets leak memory, now I do have a custom layout - a single panel on the left hand side, so that could be a factor. So I am going to have to remove them one at a time until I figure out which one is eating my ram. As a long-time linux user this is seriously disheartening. Why can't plasmashell monitor and limit the memory usage of its widgets? Why does the end user have to debug this largely on their own?

Influential Linux nerds recommended KDE Plasma to me as being a light-weight stable functional desktop environment, but I find it to be over-complicated (it took me over half an hour to find the only way to remove a widget from a panel, why isn't it an option in the right-click menu?), buggy (I have to restart kwin every other day because the entire desktop freezes up) and way to greedy in the memory department.

Is there any hope or should I install Unity which has the reputation of using rather a lot of ram from the get-go, but which is as stable as a rock?

[Snowhog]

I got home today to find plasmashell using 5.5Gb swap and 2.3Gb ram on Kubuntu 18.04. WHY?

You aren't giving us much; heck, you aren't giving us anything; to go on. Are you leaving your PC on 24/7? What do you have running? What applications/widgets have you installed? What are your PC specs?

[GreyGeek]

I got home today to find plasmashell using 5.5Gb swap and 2.3Gb ram on Kubuntu 18.04. WHY?

Other threads suggest that certain widgets leak memory, now I do have a custom layout - a single panel on the left hand side, so that could be a factor. So I am going to have to remove them one at a time until I figure out which one is eating my ram. As a long-time linux user this is seriously disheartening. Why can't plasmashell monitor and limit the memory usage of its widgets? Why does the end user have to debug this largely on their own?

Influential Linux nerds recommended KDE Plasma to me as being a light-weight stable functional desktop environment, but I find it to be over-complicated (it took me over half an hour to find the only way to remove a widget from a panel, why isn't it an option in the right-click menu?), buggy (I have to restart kwin every other day because the entire desktop freezes up) and way to greedy in the memory department.

Is there any hope or should I install Unity which has the reputation of using rather a lot of ram from the get-go, but which is as stable as a rock?

With absolutely no info to go on it is impossible to say what your problems are. The "Influential Linux nerds"? I agree with them 100%. Kubuntu 18.04 has been and is as stable as a rock since I installed it right after it went gold. I'm running three internal HDs with 16GB of RAM, an i7 CPU and an NVidia GT 650M GPU that is not settable in the BIOS as the primary but behaves as the primary because of nvidia-390, and runs faultlessly everything I throw at it. BTW, I'm running sddm. (Simple Desktop Display Manager). Here is my kwin usage:

Process 1274 - kwin_x11

Summary

The process kwin_x11 (with pid 1274) is using approximately 64.9 MB of memory.
It is using 53.6 MB privately, and a further 65.4 MB that is, or could be, shared with other programs.
Dividing up the shared memory between all the processes sharing that memory we get a reduced shared memory usage of 11.3 MB. Adding that to the private usage, we get the above mentioned total memory footprint of 64.9 MB.
Library Usage

The memory usage of a process is found by adding up the memory usage of each of its libraries, 
plus the process's own heap, stack and any other mappings, plus the stack of its 5 threads. 
Private
more
24300 KB    [heap]
16612 KB    /dev/nvidiactl
4176 KB    /usr/lib/x86_64-linux-gnu/libnvidia-glcore.so.390.48
2732 KB    /usr/lib/x86_64-linux-gnu/libkwin.so.5.12.6
1028 KB    /usr/lib/x86_64-linux-gnu/libkwin4_effect_builtins.so.1.0.0
Shared
more
10740 KB    /usr/lib/x86_64-linux-gnu/libnvidia-glcore.so.390.48
4472 KB    /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.9.5
4008 KB    /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.9.5
3376 KB    /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.9.5
2852 KB    /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.9.5
...
[SIZE=3][B]AND, MY Plasmashell[/B][/SIZE]
Process 1278 - plasmashell

Summary

The process plasmashell (with pid 1278) is using approximately 259.2 MB of memory.
It is using 242.4 MB privately, and a further 86.0 MB that is, or could be, shared with other programs.
Dividing up the shared memory between all the processes sharing that memory we get a reduced shared memory usage of 16.8 MB. Adding that to the private usage, we get the above mentioned total memory footprint of 259.2 MB.
Library Usage

The memory usage of a process is found by adding up the memory usage of each of its libraries, plus the process's own heap, stack and any other mappings, plus the stack of its 17 threads. 
Private
more
149756 KB    [heap]
69508 KB    /dev/nvidiactl
2672 KB    /usr/lib/x86_64-linux-gnu/libQt5XmlPatterns.so.5.9.5
2036 KB    /usr/lib/x86_64-linux-gnu/libnvidia-glcore.so.390.48
1668 KB    /home/jerry/.cache/plasma_theme_default_v5.30.kcache
Shared
more
10584 KB    /usr/lib/x86_64-linux-gnu/libnvidia-glcore.so.390.48
4696 KB    /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.9.5
4360 KB    /usr/lib/x86_64-linux-gnu/libQt5Core.so.5.9.5
3548 KB    /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5.9.5
3356 KB    /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5.9.5

As far as your suggestion that plasma developers "monitor and limit the memory usage of its widgets" ... that would be impractical if not impossible. How is a plasma developer supposed to know what the widget developer's intentions are with regard to memory usage? Some widget use a lot of memory and some do not. The KDE dev crew is not responsible for what widget developers do or don't do.

It could be that 5.5GB of swap and 2.5GB of RAM is normal.