Re: uarea swap-out

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>>> As page sizes increase, we also need to deal with subpage uareas.
>> Why?  Is it really worth recovering the rest of the page containing
>> the uarea?  While there certainly are machines so small that that
>> much memory is worth thinking about, I'm inclined to doubt that that
>> occurs together with pages big enough that a subpage uarea is an
>> issue.
> Well, mips can now have 16KB pages and USPACE used to be 8KB so I can
> put two uareas per page now.  And I can see going to 32KB or 64KB
> pages if you have 16+GB of ram.  The situation is closer than you
> think.

Oh, I'm not saying the situation of pages larger than uareas is far
off.

What I'm doubting is that there exists, or will exist, a machine where
(a) pages are significantly larger than uareas *and* (b) RAM is so
tight we would care about the RAM waste that would result from letting
the rest of each uarea's page sit idle.  (Oh, and (c) anyone cares
about getting NetBSD on it, I suppose.)

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