garbage-collect | garbage collector algorithm 垃圾回收算法的系列实现 | Game Engine library

Well, the title says it all: I'm wondering what is the reason why the BEAM doesn't garbage collect atoms. I'm aware of question How Erlang atoms can be garbage collected but, while related, it doesn't reply to why.

I followed the 7th Nix pill tutorial, and created a derivation that placed an executable in the nix store, i.e. /nix/store/gh66mkic4c1dys8ag8yqnv10x59b7vmh-simple/simple.

I can run that executable, either directly or via symlinks to it. However, how do I remove it? I tried deleting old generations with $ nix-env --delete-generations old, and also garbage collecting with nix-store --gc, but my derivation's output still appears at that path and can be run there.

Now that I've completed the tutorial, how do I get rid of what I've created in the nix store? Does nixos ever clean up such old derivations? Does it need to be somehow marked as irrelevant before running the delete-old-generations or garbage-collect commands?

I have a bunch of instances, each having a unique tempfile for its use (save data from memory to disk and retrieve them later).

I want to be sure that at the end of the day, all these files are removed. However, I want to leave a room for a fine-grained control of their deletion. That is, some files may be removed earlier, if needed (e.g. they are too big and not important any more).

What is the best / recommended way to achieve this?

May thoughts on that

• The try-finalize blocks or with statements are not an option, as we have many files, whose lifetime may overlap each other. Also, it hardly admits the option of finer control.

• From what I have read, __del__ is also not a feasible option, as it is not even guaranteed that it will eventually run (although, it is not entirely clear to me, what are the "risky" cases). Also (if it is still the case), the libraries may not be available when __del__ runs.

• tempfile library seems promising. However, the file is gone after just closing it, which is definitely a bummer, as I want them to be closed (when they perform no operation) to limit the number of open files.

  • The library promises that the file "will be destroyed as soon as it is closed (including an implicit close when the object is garbage collected)."

    How do they achieve the implicit close? E.g. in C# I would use a (reliable) finalizer, which __del__ is not.

• atexit library seems to be the best candidate, which can work as a reliable finalizer instead of __del__ to implement safe disposable pattern. The only problem, compared to object finalizers, is that it runs truly at-exit, which is rather inconvenient (what if the object eligible to be garbage-collected earlier?).

  • Here, the question still stands. How the library achieves that the methods always run? (Except in a really unexpected cases with which is hard to do anything)

In ideal case, it seems that a combination of __del__ and atexit library may perform best. That is, the clean-up is both at __del__ and the method registered in atexit, while repeated clean-up would be forbidden. If __del__ was called, the registered will be removed.

The only (yet crucial) problem is that __del__ won't run if a method is registered at atexit, because a reference to the object exists forever.

Thus, any suggestion, advice, useful link and so on is welcomed.

My issue: After calling a controller which generates csv file content and returns, memory is not cleared up. Which generates issue since it will slowly fill up memory and you'll end up using 100% memory on your server after awhile, this issue can be hastened by just generating larger csv files example in the project below it simply generates 3 million lines of csv file content which fills memory quite a bit.

What I want: Simply it clears the memory after the content is finished getting used.

I've tried a few thing with using statement and IDisposable but none of them fixed the issue. Only way I can think of is using pointers and clearing the RAM manually since the garbage collector for some reason is not removing the old data which is not getting used anymore.

The RAM usage problem is mostly contained around the "test" function and GetDymmyData.

I have not added code examples in this post since I've tried to do that in Issues with list not getting garbage collected after use in mvc but it ended up being too much code

Example project: https://github.com/jespper/Memory-Issue

The docs for garbage collection explain how to set the garbage collection policies with cbt but don't explain how to read the policies. The cbt reference doesn't seem to have any command to get garbage collection either. As far as I can tell, this isn't available in the GUI.

Official doc says remove cache data using cache.evict(), but there are no explanation about nested object. For example, let's think abount ROOT_QUERY like below.

I am creating a thread in lua c, but i want to keep it just in C, without making it a variable in the environment/etc. But when i throw away the thread value that gets pushed by lua_newthread, it gets garbace collected shortly after, and so becomes useless. In this thread i want to run arbitrary lua code passed by the user, allowing them to use the exclusive functions/variables that are isolated from other threads.

Is there a way to mark a thread/userdata/table value as non-garbage-collectable?

In a contrived example, I have an instance supporting the following interface:

Suppose in java, I want to do some operations when an array (e.g., int[] a = new int[3]) is garbage-collected. I know there is a finalize methods for Objects. But is there a "finalize" method for arrays?