Memory consumption

[abdelaziz-mahdy]

Describe the bug
memory is not being freed correctly i think
this is my example https://github.com/abdelaziz-mahdy/face_grouping

try to pick a dir with images in it it should extract the faces in it,

from the devtools the memory should be 100mb

but in activity monitor its 2 gb

Expected behavior
i think the memory should be the same as devtools and since they are not the same i think there is a problem with how the c part frees the memory

Desktop (please complete the following information):

• OS: Macbook pro m2

Smartphone (please complete the following information):

• Device: Macos
• ABI Version arm64

Additional context
Add any other context about the problem here.

[rainyl]

I have tested your example, yes, on windows a memory leak also observed.

It seems native resources are not correctly freed in cv.imread and cv.imencode, could you please replace the dependency of opencv_dart with issue-64 branch in your pubspec.yaml and test it? I tested on windows and it seems ok.

[abdelaziz-mahdy]

I will try to test at night, thank you for your help ❤️

[rainyl]

It seems an increase of ~20M still exists every time opening a directory, but much better now, and the reason may be an abuse of arena, but I am not clear why...

Anyway, I will reassess all arena recently.

[abdelaziz-mahdy]

i can confirm its much better now

its lower in devtools, dont know if ffi objects are not kept in the tracking or something

[rainyl]

Just for remind myself,

According to dart-lang/sdk#54233 , dart objects are small but native objects are large, so GC will not execute as we expected to free native resources timely, but I am still confusing why arena will not release memory automactically...

Releated:

• Can we / shouldn't we use Dart VM (GC) to auto manage non-Dart objects? dart-lang/sdk#54233
• In jnigen, Java objects seem to be auto managed by Dart heap, is it allowed, or shall we call dispose manually for each object? dart-lang/native#848

[abdelaziz-mahdy]

in some cases i still face the same problem, yes it got reduced alot but still happens, do you know how can i identify objects in memory so i can dispose what is not disposed, or we can check it to check why GC doesnt clean it

btw i opened devtools and forced GC but it didnt delete the objects

[rainyl]

Yes, the memory increases constantly even when I switch around different tabs... will keep tracking