partedit: limit default swap to maximum supported by kernel

[emaste]

Summary

PR:             251993
Sponsored by:   The FreeBSD Foundation

[cperciva]

It's not impossible for systems to be upgraded with more RAM later, which would allow more swap to be used. But even in that case it's likely that the original autotuned limit would be sufficient, so go ahead.

[emaste]

It's not impossible for systems to be upgraded with more RAM later

Even so I think there's typically a lot of room to grow, e.g. on my 32GB laptop swap_maxpages allows for 247GB:

$ expr $(sysctl -n vm.swap_maxpages) \* 4096 / 1024 / 1024 / 1024
247