Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix Enumerator fiber leaks #6021

merged 1 commit into from
Feb 17, 2020

Fix Enumerator fiber leaks #6021

merged 1 commit into from
Feb 17, 2020


Copy link

@headius headius commented Jan 7, 2020

This PR will include commits to reduce the chance of Enumerator#next fibers leaking.

The original issue is #6004.

So far most of the leaks appear to be caused by combining Enumerator::Lazy with Enumerator#next, since many lazy paths construct new Lazy instances in such a way that they are hard-referenced by the eventual fiber.

Lazy enumerators still may leak in the presence of Enumerator#next
calls, but this at least isolates the instantiating Lazy from the
newly-created Lazy, avoiding a backreference that might keep the
original object alive.

Given a test as shown in jruby#6004 that spins up many Lazy instances,
this patch appears to work well. It did not appear to fix the
reported leaks in that issue, however.

Example code that leaked before but is stable with this patch:

while true
  [1,2,3].lazy.reject {|x| x < 3 }.next
@headius headius added this to the JRuby milestone Jan 7, 2020
@headius headius merged commit c9e84f0 into jruby:master Feb 17, 2020
Copy link
Member Author

headius commented Feb 17, 2020

In the interest of improving things for 9.2.10 I have merged this. There's still known leaks in lazy enumerators and the root cause of #6004 remains elusive but it is a step forward.

@headius headius deleted the enumerator_leaks branch February 17, 2020 15:23
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
None yet
None yet

Successfully merging this pull request may close these issues.

None yet

1 participant