Spinlock

Spinlock (software-only)

1. turn only ping-pong like one-to-one problem

2. flag only symultaniously raising flag problem

3. Peterson's algorithm use flag and turn variable

repeat
 	flag[i] := true;
 	turn := j;
 	while (flag[j] and turn = j) //cation to and
 		//busy waiting = spinning
 	critical section
 	flag[i] := false;
 	//else code
 until false;

spinlock (hardware atomic)

atomic operation: cannot be disturbed

Lock (computer science)

In computer science, a lock or mutex (from mutual exclusion) is a synchronization primitive: a mechanism that enforces limits on access to a resource when there are many threads of execution. A lock is designed to enforce a mutual exclusion concurrency control policy, and with a variety of possible methods there exists multiple unique implementations for different applications.

https://en.wikipedia.org/wiki/Lock_(computer_science)