Christoph Lameter <clameter <at> sgi.com> wrote:
>
> Page migration is also useful for other purposes:
> 
>  1. Memory hotplug. Migrating processes off a memory node that is going
>     to be disconnected.
> 
>  2. Remapping of bad pages. These could be detected through soft ECC errors
>     and other mechanisms.

It's only useful for these things if it works with close-to-100% reliability.

And there are are all sorts of things which will prevent that - mlock,
ongoing direct-io, hugepages, whatever.

So before we can commit ourselves to the initial parts of this path we'd
need some reassurance that the overall scheme addresses these things and
that the end result has a high probability of supporting hot unplug and
remapping sufficiently well.