Re: [PATCH v5 04/14] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled()

[Lance Yang <lance.yang@linux.dev>]

Hi Andrew,

I just noticed that mm-new commit 83f151d1f7e3[1] links to this patch:

Link: https://lore.kernel.org/20260429152924.727124-5-ziy@nvidia.com

but the applied commit only has the include/linux/shmem_fs.h hunk ...
The mm/khugepaged.c hunk seems missing. Was this dropped unintentionally?

[1] https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=mm-new&id=83f151d1f7e3429100d148fbafc65203294e9f90

Thanks, Lance

On Wed, Apr 29, 2026 at 11:29:14AM -0400, Zi Yan wrote:
>Remove the READ_ONLY_THP_FOR_FS gate 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>
>Acked-by: David Hildenbrand (Arm) <david@kernel.org>
>---
> 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 93a0ba872ebe0..acb8dd961b45c 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 71209a72195ab..d6971ada8f199 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;
>+}
>+
> 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;
> }
>-- 
>2.53.0
>
>