Re: [RFC PATCH 0/2] mm: fix OOMs for binding workloads to movable zone only node

From: Michal Hocko
Date: Wed Nov 04 2020 - 02:58:22 EST


On Wed 04-11-20 15:38:26, Feng Tang wrote:
[...]
> > Could you be more specific about the usecase here? Why do you need a
> > binding to a pure movable node?
>
> One common configuration for a platform is small size of DRAM plus huge
> size of PMEM (which is slower but cheaper), and my guess of their use
> is to try to lead the bulk of user space allocation (GFP_HIGHUSER_MOVABLE)
> to PMEM node, and only let DRAM be used as less as possible.

While this is possible, it is a tricky configuration. It is essentially
get us back to 32b and highmem...

As I've said in reply to your second patch. I think we can make the oom
killer behavior more sensible in this misconfigured cases but I do not
think we want break the cpuset isolation for such a configuration.
--
Michal Hocko
SUSE Labs