Re: [RFC] [PATCH] Power Managed memory base enabling

David Rientjes
2007-03-06T17:33:50Z

On Tue, 6 Mar 2007, Mark Gross wrote:

> > Is do_migrate_pages() currently unsatisfactory for this?
>
> This looks like it should be good for this application! How stable is
> this? The next phase of this work is to export the policy interfaces
> and hook up the page migration. I'm somewhat new to the mm code.
>

Since you've already used a NUMA approach to flagging PM-memory, you'd
probably want to use this interface through mempolicy in your migration.
There's currently work to do lockless VMA scanning that was posted just
yesterday to linux-mm and that's a bottleneck in this migration.

Take a look at update_nodemask() in kernel/cpuset.c for how it migrates
pages from a source set of nodes to a destination set using
memory_migrate. The cpuset specifics are explained in
Documentation/cpusets.txt, but the basics are that you'll want to use
memory_migrate to start the migration when you remove a node from your
nodemask (another reason why I suggested the use of a nodemask instead of
a simple array).

David