Re: Question about ARM KVM stage2 contiguous bit support for contiguous hugetlb

[Marc Zyngier <maz@kernel.org>]

On Fri, 13 Mar 2026 07:09:40 +0000,
Zhou Wang <wangzhou1@hisilicon.com> wrote:
> 
> And do we have any plan to support this?

Not really.

Configurations that are looking at extracting the best possible
performance use large mappings at S2 (hugetlbfs). I'm not convinced
that there is a strong use-case for dealing with the contiguous hint
at S2 when backed by anonymous memory. If you're not under memory
pressure, THP already gives you the uplift you want. If you are under
memory pressure, you're unlikely to get the contiguity you want.

Additionally, dealing with the contiguous hint is a real pain.

If you are undertaking this work, please make sure to provide
reproducible benchmarks and results that show a definite improvement
on the majority of workloads.

Thanks,

	M.

-- 
Jazz isn't dead. It just smells funny.