From owner-freebsd-hackers  Thu Jan 14 20:32:44 1999
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To: "John S. Dyson" <dyson@dyson.iquest.net>
Cc: dillon@apollo.backplane.com, root@dyson.iquest.net, dg@root.com,
        jkh@FreeBSD.ORG, hackers@FreeBSD.ORG
Subject: Re: Review and report of linux kernel VM 
Reply-To: Jason Thorpe <thorpej@nas.nasa.gov>
From: Jason Thorpe <thorpej@nas.nasa.gov>
Date: Thu, 14 Jan 1999 20:31:25 -0800
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On Thu, 14 Jan 1999 23:01:18 -0500 (EST) 
 "John S. Dyson" <dyson@dyson.iquest.net> wrote:

 > In those cases, then they simulate the page table schemes.  (I am
 > VERY familiar with such, currently doing a port to such a machine.)

Ewww, yuck!  :-)

Anyhow, the copying of PTEs or whatever is precisely what pmap_copy() is
for, anyhow... and...

 > However, if you look at the VM code, the issues of the layer transitions
 > are significant.

...on these fancy RISC systems, the function calls are amazingly efficient
because the architecture doesn't suck nearly as bad as the x86 :-)

 > It is clear that there is *something* wrong with the place where the
 > layering is between the upper and lower level VM code.  I am not sure
 > where to put it though.

Hm, why not spell out all the things that are wrong with it?  Specifics,
John, specifics.  And, also, please use sentences that make sense :-)

"...the place where the layering is between the upper and lower level..."?

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
NAS: M/S 258-5                                       Work: +1 650 604 0935
Moffett Field, CA 94035                             Pager: +1 650 940 5942

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