2001 Toyota Camry. 99,000 miles. V6 engine. Engine oil

My 2001 toyota camry has 99,000 miles. Lately, when I start car puff of white smoke comes out of exhaust. There is no service engine light on in my car. Also, I have been having to put a lot more oil in than ever before, but it is not leaking underneath. It has alos been idling rough. Do you know what the cause could be and possible solutions? Someone told me the camry also builds up on sludge in oil which could be the problem. Thanks.