[v4,20/25] mm/mlock: Skip ZONE_DEVICE PMDs during mlock

Commit Message

Alistair Popple Dec. 17, 2024, 5:13 a.m. UTC

At present mlock skips ptes mapping ZONE_DEVICE pages. A future change
to remove pmd_devmap will allow pmd_trans_huge_lock() to return
ZONE_DEVICE folios so make sure we continue to skip those.

Signed-off-by: Alistair Popple <[e-mail]>
---
 mm/mlock.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

David Hildenbrand Dec. 17, 2024, 10:28 p.m. UTC | #1

On 17.12.24 06:13, Alistair Popple wrote:
> At present mlock skips ptes mapping ZONE_DEVICE pages. A future change
> to remove pmd_devmap will allow pmd_trans_huge_lock() to return
> ZONE_DEVICE folios so make sure we continue to skip those.
> 
> Signed-off-by: Alistair Popple <[e-mail]>
> ---
>   mm/mlock.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/mm/mlock.c b/mm/mlock.c
> index cde076f..3cb72b5 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -368,6 +368,8 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
>   		if (is_huge_zero_pmd(*pmd))
>   			goto out;
>   		folio = pmd_folio(*pmd);
> +		if (folio_is_zone_device(folio))
> +			goto out;
>   		if (vma->vm_flags & VM_LOCKED)
>   			mlock_folio(folio);
>   		else

Acked-by: David Hildenbrand <[e-mail]>

Patch

diff --git a/mm/mlock.c b/mm/mlock.c
index cde076f..3cb72b5 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -368,6 +368,8 @@  static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
 		if (is_huge_zero_pmd(*pmd))
 			goto out;
 		folio = pmd_folio(*pmd);
+		if (folio_is_zone_device(folio))
+			goto out;
 		if (vma->vm_flags & VM_LOCKED)
 			mlock_folio(folio);
 		else