Re: [PATCH v2 10/10] mm: hwpoison_user_mappings() try_to_unmap() with TTU_SYNC

[HORIGUCHI NAOYA(堀口 直也)]

On Tue, Jun 08, 2021 at 09:30:00PM -0700, Hugh Dickins wrote:
> TTU_SYNC prevents an unlikely race, when try_to_unmap() returns shortly
> before the page is accounted as unmapped.  It is unlikely to coincide
> with hwpoisoning, but now that we have the flag, hwpoison_user_mappings()
> would do well to use it.
>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> ---
> Patch added since the v1 series was posted.
>
>  mm/memory-failure.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index b6806e446567..e16edefca523 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1060,7 +1060,7 @@ static int get_hwpoison_page(struct page *p, unsigned long flags,
>  static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
>  				  int flags, struct page **hpagep)
>  {
> -	enum ttu_flags ttu = TTU_IGNORE_MLOCK;
> +	enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC;

Thanks for improving thp code.

Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>