Linux – Move swap contents back to the RAM once there’s free memory

Unfortunately, no. The way Windows virtual memory system works, many of the pages simply can't be mapped until they fault and can't be stored in memory unless they're mapped. So Windows has to wait until the pages are accessed.

You probably only need a small amount of swap. When you have sufficient RAM for your computer's typical working set, which I'm pretty sure you do, you only need swap for two things:

1. You need swap to get information that will likely never be accessed out of RAM to free up more space for disk cache. Many applications run on system startup and will never be accessed again. You don't want any pages they dirtied stuck in RAM forever. So you need swap to hold them.

2. You need swap to cover allocations that will never be filled. This space simply has to be available, even though it will not be used. Without it, the system will have to refuse to allocate memory even when it has plenty of free physical RAM because it has insufficient backing store to permit all of its allocations to be used at once.

Neither of these requires a large amount of swap. 16GB, for example, should be more than enough. The purpose is not to let you run bigger working sets at the cost of speed. The purpose is to let you use your 64GB effectively and not have to clog it with junk or reserve it for edge cases that will never happen.

(I agree with Bert that 4GB is quite likely to be sufficient.)