Suppose processes P1-P4 with the given priorities and resource allocations. 1 is the highest priority and 4 is the lowest priority. Let us also assume that the "no preemption" condition is now relaxed by allowing preemption of resources by processes of higher priority. For example, P3 may preempt P2 or P4 if it needs a resource which they are holding. If P3 preempts one of these processes, say P4, then P4 release all the resources it is holding. Show one sequence of events in which resources are allocated to the 4 processes and the resulting preemptions, if any, until all new requests are serviced. Current allocations are shown below. Each resource has 4 instances. Try to minimize the preemptions as they are expensive. Process ID Process Priority Current allocation New request R1 R2 R1 R2 P1 1 2 1 2 1 P2 3 0 1 1 0 P3 2 1 1 0 1 P4 4 1 1 2 1
Suppose processes P1-P4 with the given priorities and resource allocations. 1 is the highest priority and 4 is the lowest priority. Let us also assume that the "no preemption" condition is now relaxed by allowing preemption of resources by processes of higher priority. For example, P3 may preempt P2 or P4 if it needs a resource which they are holding. If P3 preempts one of these processes, say P4, then P4 release all the resources it is holding. Show one sequence of events in which resources are allocated to the 4 processes and the resulting preemptions, if any, until all new requests are serviced. Current allocations are shown below. Each resource has 4 instances. Try to minimize the preemptions as they are expensive.
Process ID | Process Priority | Current allocation | New request | ||
R1 | R2 | R1 | R2 | ||
P1 | 1 | 2 | 1 | 2 | 1 |
P2 | 3 | 0 | 1 | 1 | 0 |
P3 | 2 | 1 | 1 | 0 | 1 |
P4 | 4 | 1 | 1 | 2 | 1 |
Trending now
This is a popular solution!
Step by step
Solved in 2 steps