Re: [RFC PATCH] mm: hugetlb: remove __GFP_THISNODE flag when dissolving the old hugetlb

From: Michal Hocko
Date: Mon Feb 05 2024 - 09:23:25 EST


On Mon 05-02-24 21:06:17, Baolin Wang wrote:
[...]
> > It is quite possible that traditional users (like large DBs) do not use
> > CMA heavily so such a problem was not observed so far. That doesn't mean
> > those problems do not really matter.
>
> CMA is just one case, as I mentioned before, other situations can also break
> the per-node hugetlb pool now.

Is there any other case than memory hotplug which is arguably different
as it is a disruptive operation already.

> Let's focus on the main point, why we should still keep inconsistency
> behavior to handle free and in-use hugetlb for alloc_contig_range()? That's
> really confused.

yes, this should behave consistently. And the least surprising way to
handle that from the user configuration POV is to not move outside of
the original NUMA node.
--
Michal Hocko
SUSE Labs