I don’t see how swap has much chance to fragment. A swapfile has to be fully allocated up front and cannot be CoW. If it’s allocated well in the first place, it will stay that way.
The swap code doesn’t really do I/O through the filesystem. AIUI, it locks the file, gets the disk block #s from the FS, and after that it accesses those blocks directly.
Son of a bitch. Instead of “turning shit the fuck off”, is windows putting the wifi card into some sort of eternal WoL mode when it shuts down? And the wifi card isn’t resetting at boot time (or honoring a reset command) to give the linux drivers a known starting state?