Add multiple locks which can be obtained based on segment name in lookupOrCreateFSM

[npawar]

Adding segment name based locks instead of synchronizing the method lookupOrCreateFSM. The latter prevents even other segments from entering the method and accessing their own fsm. A stall in a single call (could be on zk access, gc) can create a ripple effect delay in all segments waiting on that method

[kishoreg]

I might be wrong here. Cant parse the indentation properly on phone.

There is possibility that fsm can be null in the end rt? I thought it’s better to lookup the fsmmap in the end.

[npawar]

I might be wrong here. Cant parse the indentation properly on phone.

There is possibility that fsm can be null in the end rt? I thought it’s better to lookup the fsmmap in the end.

The idea is to lookup in the fsmMap, and use that if not null. If it is null, then create a new instance of fsm and put it in the map. The fsm cannot be null after the if-else if-else block. Which place are you referring to?

[kishoreg]

My bad, I thought there were two if blocks (outer and inner). In other words, we dont need a lock to check the existence in fsmMap we need the lock if the fsm does not exists.

But it's not a big deal in this code path.

[kishoreg]

LGTM.

[sunithabeeram]

LGTM.