meaning of 'have at it'

Hi everybody,

Came across this new to me expression:

A: Oh … mind if I look around your house a little?
B: Have at it.

Now, I figured that it means roughly “knock yourself out”, but I’m not sure other natives are cognizant of this expression.
So, do you know it?


Yes I do, and yes, it does have the same inference,

doesn’t this mean something like “do it, go ahead”?

That would be my definition of it, Sergey.

There is an idiom: Have at it, and have it. = do it and you get it.

Thank you!