Re: [PATCH v3 08/13] mm/huge_memory: remove unnecessary sanity checks

[Suren Baghdasaryan <surenb@google.com>]

On Fri, Mar 20, 2026 at 11:07 AM Lorenzo Stoakes (Oracle)
<ljs@kernel.org> wrote:
>
> These checks have been in place since 2014, I think we can safely assume
> that we are in a place where we don't need these as runtime checks.
>
> In addition there are 4 other invocations of folio_remove_rmap_pmd(), none
> of which make this assertion.
>
> If we need to add this assertion, it should be in folio_remove_rmap_pmd(),
> and as a VM_WARN_ON_ONCE(), however these seem superfluous so just remove
> them.
>
> Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>

Reviewed-by: Suren Baghdasaryan <surenb@google.com>

> ---
>  mm/huge_memory.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index fca44aec6022..c5b16c218900 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2371,7 +2371,6 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>
>                 flush_needed = true;
>                 folio_remove_rmap_pmd(folio, &folio->page, vma);
> -               WARN_ON_ONCE(folio_mapcount(folio) < 0);
>         } else if (pmd_is_valid_softleaf(orig_pmd)) {
>                 const softleaf_t entry = softleaf_from_pmd(orig_pmd);
>
> @@ -2402,7 +2401,6 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>
>         if (folio_is_device_private(folio)) {
>                 folio_remove_rmap_pmd(folio, &folio->page, vma);
> -               WARN_ON_ONCE(folio_mapcount(folio) < 0);
>                 folio_put(folio);
>         }
>
> --
> 2.53.0
>