On Thu, 26 Apr 2007, Linus Torvalds wrote:
Once you have that snapshot image in user space you can do anything you
want. And again: you'd hav a fully working system: not any degradation
*at*all*. If you're in X, then X will continue running etc even after the
snapshotting, although obviously the snapshotting will have tried to page
a lot of stuff out in order to make the snapshot smaller, so you'll likely
be crawling.
In fact... If you're just paging out to make a smaller snapshot (ie, not
to free up memory), couldn't you just swap it out (if it's not backed by a
file) then mark it as "half-released"... ie, the snapshot writing code
ignores it knowing that it will be available on disk at resume, but then
when the snapshot is complete it's still available in physical RAM,
preventing user-space from crawling due to the necessity of paging it all
back in?