Personally, I would never put my laptop in the overhead. Are there no spaces on the floor? Some laptops (13" or smaller) can easily fit also in the seat back pocket.

Generally speaking, overhead should accommodate large carryons first, and then at the end of boarding, if there are spaces, then smaller items. People often incorrectly place their carryons in the overhead, which is the contributing factor to lack of bin spaces and slow boarding process.