Two variables: Valves and injectors.
Smoke is unburnt fuel so you need to determine why its not combusting
Given ten miles use before the problem began I'd suspect the valve
adjustment. A TURBO engine at 70 degrees F. has its intakes set to .004
INCH and its exhaust to .014 INCH. Though your engine is not a turbo it
will have similar specs.
If you're confident the valve adjustment is OK, I'd move on to the
injectors - one of them is dribbling - stuck open and the smoke is from
fuel burning in the exhaust manifold. That would also explain the knocking.
Hope this helps.