Re: [RFC PATCH 3/3] mm/mincore: avoid touching the PTL

[David Hildenbrand]

On 07.08.25 17:27, Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> mincore only interested in the existence of a page, which is a
> changing state by nature, locking and making it stable is not needed.
> And now neither mincore_page or mincore_swap requires PTL, this PTL
> locking can be dropped.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> ---
>   mm/mincore.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/mincore.c b/mm/mincore.c
> index 1ac53acac239..cc4460aba1f9 100644
> --- a/mm/mincore.c
> +++ b/mm/mincore.c
> @@ -153,13 +153,13 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>   		goto out;
>   	}
>   
> -	ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
> +	ptep = pte_offset_map(pmd, addr);

I agree with Jann, that if we move away from the PTL, we better have a 
very good reason (+performance numbers).

--
Cheers,

David / dhildenb