Re: [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure

[Lance Yang]

On Wed, May 06, 2026 at 09:21:30AM +0800, Ye Liu wrote:
>From: Ye Liu <liuye@xxxxxxxxxx>
>
>__khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the
>corresponding mm_slot.  If mm_slot_alloc() fails, the function
>returns with the flag set but without inserting the mm into the
>khugepaged tracking structures.
>
>This leaves the mm in an inconsistent state: it is marked as
>registered (MMF_VM_HUGEPAGE set), but will never be scanned by
>khugepaged.  Future attempts to register the mm are skipped since
>khugepaged_enter_vma() checks the flag and returns early.
>
>Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails,
>restoring the ability to retry registration later.
>
>Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for struct mm_slot")

Nit: the title does not exactly match the original commit subject.

It should be

Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for "struct mm_slot"")

which includes quotes around "struct mm_slot".

No need to resend; I think Andrew can fix it up when applying :)

>Signed-off-by: Ye Liu <liuye@xxxxxxxxxx>
>---

Thanks, LGTM.
Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>