Critical section (CS)
At any point in time, only 1 process can execute in the critical section.
Elaboration
This makes our mutations atomic.
For instance, suppose we had 2 processes executing concurrently, writing to file. They will write in an interleaving fashion. However, if we want 1 process to write, followed by second process, we need someway to control that behaviour.
Properties
- We want only 1 process to access critical section at once
At least 1 process should be accessing
Progress
A process should eventually execute
Bounded wait. If this doesn’t happen, the resources are blocked forever.
Other processes outside of the critical section should not block the process within. Otherwise this leads to deadlock.
Another interesting occurrence of this is livelock. This happens when processes change state, to avoid deadlock. If that’s all they do, this is a livelock.
