Re: [PATCH 7.2 v4 04/12] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled()

David Hildenbrand (Arm)
2026-04-24T12:48:00Z

On 4/24/26 04:49, Zi Yan wrote:
> Remove READ_ONLY_THP_FOR_FS and khugepaged for file-backed pmd-sized
> hugepages are enabled by the global transparent hugepage control.
> khugepaged can still be enabled by per-size control for anon and shmem when
> the global control is off.
>
> Add shmem_hpage_pmd_enabled() stub for !CONFIG_SHMEM to remove
> IS_ENABLED(SHMEM) in hugepage_enabled().
>
> Clean up hugepage_enabled() by moving anon code to anon_hpage_enabled().
>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---
> include/linux/shmem_fs.h | 2 +-
> mm/khugepaged.c | 26 ++++++++++++++++----------
> 2 files changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> index 93a0ba872ebe..acb8dd961b45 100644
> --- a/include/linux/shmem_fs.h
> +++ b/include/linux/shmem_fs.h
> @@ -127,7 +127,7 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
> void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end);
> int shmem_unuse(unsigned int type);
>
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SHMEM)
> unsigned long shmem_allowable_huge_orders(struct inode *inode,
> struct vm_area_struct *vma, pgoff_t index,
> loff_t write_end, bool shmem_huge_force);
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 726f8ace01af..cdd4b37e4a68 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -524,26 +524,32 @@ static inline int collapse_test_exit_or_disable(struct mm_struct *mm)
> mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
> }
>
> +static inline bool anon_hpage_enabled(void)
> +{
> + if (READ_ONCE(huge_anon_orders_always))
> + return true;
> + if (READ_ONCE(huge_anon_orders_madvise))
> + return true;
> + if (READ_ONCE(huge_anon_orders_inherit) &&
> + hugepage_global_enabled())
> + return true;
> + return false;
> +}

Ah, that is based on Nicos work, right?

> +
> static bool hugepage_enabled(void)
> {
> /*
> * We cover the anon, shmem and the file-backed case here; file-backed
> - * hugepages, when configured in, are determined by the global control.
> + * hugepages are determined by the global control.
> * Anon hugepages are determined by its per-size mTHP control.
> * Shmem pmd-sized hugepages are also determined by its pmd-size control,
> * except when the global shmem_huge is set to SHMEM_HUGE_DENY.
> */
> - if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
> - hugepage_global_enabled())
> - return true;
> - if (READ_ONCE(huge_anon_orders_always))
> + if (hugepage_global_enabled())
> return true;
> - if (READ_ONCE(huge_anon_orders_madvise))
> - return true;
> - if (READ_ONCE(huge_anon_orders_inherit) &&
> - hugepage_global_enabled())
> + if (anon_hpage_enabled())
> return true;
> - if (IS_ENABLED(CONFIG_SHMEM) && shmem_hpage_pmd_enabled())
> + if (shmem_hpage_pmd_enabled())
> return true;
> return false;
> }

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

--
Cheers,

David