Subject: Re: leftovers
To: Chuck Silvers <chuq@chuq.com>
From: Manuel Bouyer <bouyer@antioche.eu.org>
List: port-xen
Date: 05/29/2005 19:36:51
On Sun, May 29, 2005 at 07:21:54AM -0700, Chuck Silvers wrote:
> currently pmap_remap_pages() always sets PG_M in the new PTE, which is
> a bit odd.  if this is really a good thing to be doing, it would be better
> to just have all the caller pass in VM_PROT_WRITE in the flags, to maximize
> the commonality with pmap_enter().  I'll also leave that to someone who
> knows more what what this function is doing.

We are remplacing a page with another one in the back of UVM. This is
equivalent of changing the content of the page, so I guess setting PG_M is
appropriate.
Also, PG_RW is set unconditionally, because I don't know how to get this
information for the old page when it was not mapped. But even if it's RO
(which I don't think is ever the case currently) we have to assume it's
modified. Also note that this new mapping is wired, so I'm not sure PG_M is
really relevant in this case.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--