Pergola attached to house and load capacity for 6x6 post
The 6x6 and the double 2x12 are sufficient in themselves for your swing.  But the 2x12s may not be attached securely enough to the 6x6 posts, and/or the pergola may not be attached securely enough to the house. 

Also, once the temporary diagonal cross braces on the 6x6 shown in the photo are removed, there may not be enough lateral stability. If you were to convert the pergola into a roof, and sheathed the roof with plywood, then there would be enough lateral stability assuming the framing is attached securely enough to the house.