Consider Peterson’s algorithm for mutual exclusion between two concurrent processes i and j. The program executed by process is shown below.
flag [i] = true;
turn = j;
while ( P ) do no-op;
Enter critical section, perform actions, then exit critical
flag [ i ] = false;
Perform other non-critical section actions.
For the program to guarantee mutual exclusion, the predicate P in the while loop should be.
(A) flag[j] = true and turn = i
(B) flag[j] = true and turn = j
(C) flag[i] = true and turn = j
(D) flag[i] = true and turn = i
To ensure the mutual exclusion, we have to take care that ‘turn’ value which is ‘j’ so we should not allow that process in CS which is having flag[j] = true.
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