Salax .. both are same. From the state of Kerala, south India. Mallu came from the word Malayali ( one who speaks Malayalam).
Malayalam is the monther tongue of Keralites.
I think almost 90% of the Indian expatriates in GCC countries must be Keralites. IN all positions from labourers to CEOs....
There are many business giants too.. including the emkey group(lulu) , Gulfar..etc

I am also a Keralite., and am proud of being one.
cheers