Re: NUMA policy interface

Mike Kravetz
2005-08-04T22:44:42Z

On Thu, Aug 04, 2005 at 03:19:52PM -0700, Christoph Lameter wrote:
> This code already exist in the memory hotplug code base and Ray already
> had a working implementation for page migration. The migration code will
> also be necessary in order to relocate pages with ECC single bit failures
> that Russ is working on (of course that will only work for some pages) and
> for Mel Gorman's defragmentation approach (if we ever get the split into
> differnet types of memory chunks in).

Yup, we need page migration for memory hotplug. However, for hotplug
we are not too concerned about where the pages are migrated to. Our
primary concern is to move them out of the block/section that we want
to offline. Suspect this is the same for pages with ECC single bit
failures. In fact, this is one possible use of the hotplug code.
Notice a failure. Migrate all pages off the containing DIMM. Offline
section corresponding to DIMM. Replace the DIMM. Online section
corresponding to DIMM. Of course, your hardware needs to be able to
do this.

--
Mike