When the car parked overnight it always gives me a puff of grey smoke in the morning. Also I just added 2 qtrs. of oil since my last oil change, approx. 3K miles ago. The oil level was at the min. mark. Otherwise the car doesn't smoke. The valve job was done at 175K miles and it has about 250K miles now. Is this normal to consume oil like that? And what this smoke might indicate?

Your comments are appreciated.

Thanks