Re: [PATCH 2/4] Add replace_page(), change the mapping of pte fromone page into another

From: Izik Eidus
Date: Tue Nov 11 2008 - 16:56:00 EST


Christoph Lameter wrote:
On Tue, 11 Nov 2008, Avi Kivity wrote:

Christoph Lameter wrote:
page migration requires the page to be on the LRU. That could be changed
if you have a different means of isolating a page from its page tables.

Isn't rmap the means of isolating a page from its page tables? I guess I'm
misunderstanding something.

In order to migrate a page one first has to make sure that userspace and
the kernel cannot access the page in any way. User space must be made to
generate page faults and all kernel references must be accounted for and
not be in use.
This is really not the case for ksm,
in ksm we allow the page to be accessed all the time, we dont have to swap the page
like migrate.c is doing...

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