Read: Read-Copy Update paper
Hand-In Procedure
You are to turn in this homework during lecture. Please write up your answers to the exercises below and hand them in to a 6.828 staff member at the beginning of lecture.
Read-Copy Update
This paper describes an approach to eliminating read locks from data structures that obey certain properties. RCU has been used in various subsystems of Linux (there are even graphs of RCU usage in Linux).
Please, hand in an answer to the following question:
| The paper describes how they applied RCU techniques to Linux's file descriptor arrays. Why it safe for read-only access to the file descriptor arrays to proceed without taking locks when RCU is used to expand file descriptor arrays? Why are read-only operations that are operating on the "old" version of an array not in danger of accessing freed memory? |
This completes the homework.