Starvation
| Depends on | Processes • Resources |
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(Resource) starvation is often linked with deadlocks in that it can (potentially) cause progress to stop. However this is really more of a scheduling issue.
A process is ‘starved’ if it can’t get some resource(s) which it needs to proceed. This can be caused by other processes competing for (and winning) the resource.
Example: A printer spooler picks the next job by queuing users alphabetically: Aaron is happy with the service but Zachary has a long wait at busy times. This example is clearly fixable with a fairer scheduling algorithm, such as one based on a FIFO queue.
One of the possible resources is processor time. In an interactive system it is important that the process scheduler is able to give some time even to low-priority tasks. (They may get a smaller share than the higher priority processes.) Effective priority may therefore be raised as a process ‘ages’.
On the other hand, a real-time system should ‘finish’ all its pending jobs and go idle periodically, in which case this should guarantee starvation cannot occur. (As long as the assumptions are really true.)
| Also refer to: | Operating System Concepts, 10th Edition: Chapter 5.3.4, pages 213 |
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