Liulei worked on the containerd/containerd repository, focusing on refactoring the OOM Watcher subsystem to improve modularity and maintainability. By decoupling the OOM Watcher from the shim package and migrating its event handling to the events.Publisher interface in both v1 and v2, Liulei reduced cross-package dependencies and enhanced testability. This work involved careful dependency management and system programming in Go, ensuring that the OOM Watcher could operate independently of the shim while maintaining compatibility with existing event flows. The refactor addressed architectural concerns, resulting in a more modular codebase that is easier to maintain and extend in future development.