From: "nagachika (Tomoyuki Chikanaga) via ruby-core" <ruby-core@...>
Date: 2023-03-21T07:49:37+00:00
Subject: [ruby-core:112962] [Ruby master Bug#19398] Memory leak in WeakMap

Issue #19398 has been updated by nagachika (Tomoyuki Chikanaga).

Backport changed from 2.7: REQUIRED, 3.0: REQUIRED, 3.1: REQUIRED, 3.2: DONE to 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE, 3.2: DONE

ruby_3_1 0d00732d39de1e5ecce738260a1e49d8af52e12a merged revision(s) c6f84e918943a0bf8db6fee556fc53180d257510.

----------------------------------------
Bug #19398: Memory leak in WeakMap
https://bugs.ruby-lang.org/issues/19398#change-102489

* Author: peterzhu2118 (Peter Zhu)
* Status: Closed
* Priority: Normal
* Backport: 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE, 3.2: DONE
----------------------------------------
Pull request: https://github.com/ruby/ruby/pull/7223

There's a memory leak in ObjectSpace::WeakMap due to not freeing the `struct weakmap`. It can be seen in the following script:

```ruby
100.times do
  10000.times do
    ObjectSpace::WeakMap.new
  end

  # Output the Resident Set Size (memory usage, in KB) of the current Ruby process
  puts `ps -o rss= -p #{$$}`
end
```

This is the memory usage graph before and after the patch:

![](chart.png)


---Files--------------------------------
chart.png (26.9 KB)


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