On 2024/2/5 22:23, Michal Hocko wrote:
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.
Yes, like I said before the longterm pinning, memory failure and the
users of alloc_contig_pages() may also break the per-node hugetlb pool.
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.
So you mean we should also add __GFP_THISNODE flag in
alloc_migration_target() when allocating a new hugetlb as the target for
migration, that can unify the behavior and avoid breaking the per-node pool?
