Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!husc6!bbn!mit-eddie!rutgers!apple!bionet!agate!ucbvax!hplabs!hpda!hpcupt1!vandys
From: vandys@hpcupt1.HP.COM (Andrew Valencia(Seattle))
Newsgroups: comp.unix.microport
Subject: Re: V.3 + top
Message-ID: <10770006@hpcupt1.HP.COM>
Date: 24 Oct 88 16:35:55 GMT
Article-I.D.: hpcupt1.10770006
References: <468@alice.marlow.uucp>
Organization: Hewlett Packard, Cupertino
Lines: 15

/ hpcupt1:comp.unix.microport / dave@micropen (David F. Carlson) / 10:05 am  Oct 21, 1988 /
>It is my impression (and I may be wrong about modern UNIXes) that the u part
>of a process is distinct from the proc part of a process *solely* so that
>the u part may be swapped out when not running but that the proc part is
>never swapped so that scheduling is not produce a swapping deadlock.

	Originally, yes.  But as with all features, cruft lands on them and
becomes part of the whole.  Originally, being swapped out was virtually
equated with moving the U area out of memory.  These days, a number of other
things rank right up there with the U area.  Page tables, for instance.
They tend to use even more space than U areas.  The U area's relationship
to the actions of the VM system has become less dominating than it once
was, as all manner of stuff gets heaped into the memory management picture.

					Andy