Additionally, a (IMO valid) maxim of sysadmins has been "a properly 
configured server doesn't swap".  There should be no reason why this 
maxim becomes invalid over time.  When Linux starts to swap out apps the 
sysadmin knows will be useful in an hour, or six hours, or a day just 
because it needs a bit more file cache, I get worried.

There IMO should be some way to balance the amount of anon-vma's such 
that the sysadmin can say "stop taking 70% of my box's memory for 
disposable cache, use it instead for apps you would otherwise swap out, 
you memory-hungry kernel you."