Provide API to Free Retained Widget Memory in GTK4

[Skxxtz]

Problem and Expected Behavior

Say I have a GtkListView setup including a CustomSorter, CustomFilter, and a Factory. Whenever all of them are destroyed, I would expect the memory usage of my application to go down – it doesn't.

After some research, I came to the conclusion that this might be some internal widget cache or a "memory reservation" for later use. Even after calling Application::hold and then destroying and dropping the window entirely, the memory stays allocated.

However, I would like to have the possibility to shrink the memory back to what it actually needs. My application is dormant but runs in the background but still has this memory allocated, which is confusing and unnecessary.

[sdroege]

Unless there are bugs in your code (can you share?) there's nothing that the bindings do in a special way here. You should be able to reproduce the same issue in C and should probably report it to GTK itself here with a minimal C testcase: https://gitlab.gnome.org/GNOME/gtk

[Skxxtz]

Hi there, thanks for the response.

I don't rule out that my code is the issue, it's certainly a possibility. The code for the application is in this file: Sherlock Emoji Picker.

Basically, I have a custom application launcher to which this is a part of. Whenever the user selects this functionality, a new stack page is created, containing the logic from that file. After the user is done with it, the entire stack page is destroyed and its children are confirmed to be dropped. When inspecting the resources usage of Sherlock, it still has elevated memory though. This issue is especially annoying whenever Sherlock is run in daemon mode, keeping the application alive even when no window is active anymore.

[sdroege]

Nothing obviously wrong there AFAICS. Can you check if this can be reproduced with a minimal example, ideally in C but otherwise in Rust? Also how do you measure memory usage?

This probably has to be reported to GTK itself in any case.

[Skxxtz]

I'll try to do that when I find the time for it. Thanks for your help anyways!