Re: [v2 PATCH 5/9] mm: vmscan: demote anon DRAM pages to PMEM node

[Yang Shi]

On 4/11/19 7:31 AM, Dave Hansen wrote:
> On 4/10/19 8:56 PM, Yang Shi wrote:
> >   include/linux/gfp.h            |  12 ++++
> >   include/linux/migrate.h        |   1 +
> >   include/trace/events/migrate.h |   3 +-
> >   mm/debug.c                     |   1 +
> >   mm/internal.h                  |  13 +++++
> >   mm/migrate.c                   |  15 ++++-
> >   mm/vmscan.c                    | 127 +++++++++++++++++++++++++++++++++++------
> >   7 files changed, 149 insertions(+), 23 deletions(-)
> Yikes, that's a lot of code.
>
> And it only handles anonymous pages?

Yes, for the time being. But, it is easy to extend to all kind of pages.

> Also, I don't see anything in the code tying this to strictly demote
> from DRAM to PMEM.  Is that the end effect, or is it really implemented
> that way and I missed it?

No, not restrict to PMEM. It just tries to demote from "preferred node" 
(or called compute node) to a memory-only node. In the hardware with 
PMEM, PMEM would be the memory-only node.

Thanks,
Yang