Use linked list for interaction task queue
Use linked list for interaction task queue

Summary: Reduce steady-state memory usage compared to deque

Reviewed By: yfeldblum

Differential Revision: D29961124

fbshipit-source-id: f00e9241efa28066c305f5cd95e659e46afc102a

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift