> Date: Sun, 4 Dec 1994 07:38:56 -0500
> From: "Charles M. Hannum" <mycroft@gnu.ai.mit.edu>

>    My concern about throwing away mappings is that the VM code may
>    in some cases be able to benefit from knowlede of the fact that
>    some mapping is no longer installed.
> 
> I'm not sure I believe this is going to buy you anything.  Maybe you
> should generate some statistics on this behaviour under normal use
> first.

I think you're right, but I'm not sure how to measure what I want
to know, which is basically:  "Did I avoid a page shortage by 
deactivating pages earlier than they would have been otherwise?"

[ how to deactivate ]
> It seems pretty easy to me:

Thanks.  I found an example in vm_pageout.c also.

Gordon