Re: [PATCH 13/35] autonuma: add page structure fields

Peter Zijlstra
2012-05-29T14:54:46Z

On Tue, 2012-05-29 at 09:56 -0400, Rik van Riel wrote:
> On 05/29/2012 09:16 AM, Peter Zijlstra wrote:
> > On Fri, 2012-05-25 at 19:02 +0200, Andrea Arcangeli wrote:
>
> > 24 bytes per page.. or ~0.6% of memory gone. This is far too great a
> > price to pay.
> >
> > At LSF/MM Rik already suggested you limit the number of pages that can
> > be migrated concurrently and use this to move the extra list_head out of
> > struct page and into a smaller amount of extra structures, reducing the
> > total overhead.
>
> For THP, we should be able to track this NUMA info on a
> 2MB page granularity.

Yeah, but that's another x86-only feature, _IF_ we're going to do this
it must be done for all archs that have CONFIG_NUMA, thus we're stuck
with 4k (or other base page size).