mirror of
https://github.com/ruby/ruby.git
synced 2026-01-29 05:24:23 +00:00
994257ab06
Continually locking a mutex m can lead to starvation if all other threads are on the waitq of m. See https://bugs.ruby-lang.org/issues/21840 for more details. Solution: When a thread `T1` wakes up `T2` during mutex unlock but `T1` or any other thread successfully acquires it before `T2`, then we record the `running_time` of the thread during mutex acquisition. Then during unlock, if that thread's running_time is less than the saved running time, we set it back to the saved time. Fixes [Bug #21840]