Re: [patch 0/6] MMU Notifiers V6

Christoph Lameter
2008-02-08T23:32:31Z

On Fri, 8 Feb 2008, Andrew Morton wrote:

> What about ib_umem_get()?

Ok. It pins using an elevated refcount. Same as XPmem right now. With that
we effectively pin a page (page migration will fail) but we will
continually be reclaiming the page and may repeatedly try to move it. We
have issues with XPmem causing too many pages to be pinned and thus the
OOM getting into weird behavior modes (OOM or stop lru scanning due to
all_reclaimable set).

An elevated refcount will also not be noticed by any of the schemes under
consideration to improve LRU scanning performance.