Re: [PATCH v3 04/12] mm: hugetlb_vmemmap: generalize vmemmap page allocation

[Muchun Song]

> On Nov 4, 2026, at 10:35, Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
> 
> Vmemmap page allocation is currently tied to restoring a virtual range
> and assumes an empty destination list.  These constraints prevent it from
> being reused when pages are requested independently of a vmemmap range or
> appended to an existing list.
> 
> Generalize the allocator and give it an all-or-nothing list contract so
> the restore and optimization paths can share the same allocation policy.
> This also allows HVO head-page allocation to fail gracefully under memory
> pressure without triggering the OOM killer.

Before this report [1], I did not realize that this unexpected behavior
change fixed a real issue. Therefore, in the next version update, I will
extract the GFP_KERNEL modification from this patch as a prerequisite patch
and place it at the very front of this series to fix this issue, so as to
facilitate backporting.

[1] https://lore.kernel.org/all/20261104133938.50974-1-zhangyili01@xxxxxxxxx/

Thanks,
Muchun