Re: [PATCH kvm-next V11 0/7] Add NUMA mempolicy support for KVM guest-memfd

Sean Christopherson
2025-10-15T18:05:57Z

On Wed, 27 Aug 2025 17:52:41 +0000, Shivank Garg wrote:
> This series introduces NUMA-aware memory placement support for KVM guests
> with guest_memfd memory backends. It builds upon Fuad Tabba's work (V17)
> that enabled host-mapping for guest_memfd memory [1] and can be applied
> directly applied on KVM tree [2] (branch kvm-next, base commit: a6ad5413,
> Merge branch 'guest-memfd-mmap' into HEAD)
>
> == Background ==
> KVM's guest-memfd memory backend currently lacks support for NUMA policy
> enforcement, causing guest memory allocations to be distributed across host
> nodes according to kernel's default behavior, irrespective of any policy
> specified by the VMM. This limitation arises because conventional userspace
> NUMA control mechanisms like mbind(2) don't work since the memory isn't
> directly mapped to userspace when allocations occur.
> Fuad's work [1] provides the necessary mmap capability, and this series
> leverages it to enable mbind(2).
>
> [...]

Applied the non-KVM change to kvm-x86 gmem. We're still tweaking and iterating
on the KVM changes, but I fully expect them to land in 6.19.

Holler if you object to taking these through the kvm tree.

[1/7] mm/filemap: Add NUMA mempolicy support to filemap_alloc_folio()
https://github.com/kvm-x86/linux/commit/601aa29f762f
[2/7] mm/filemap: Extend __filemap_get_folio() to support NUMA memory policies
https://github.com/kvm-x86/linux/commit/2bb25703e5bd
[3/7] mm/mempolicy: Export memory policy symbols
https://github.com/kvm-x86/linux/commit/e1b4cf7d6be3

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