Re: [PATCH v4 62/66] mm/swapfile: Use maple tree iterator instead of vma linked list

[Vlastimil Babka]

On 12/1/21 15:30, Liam Howlett wrote:
> From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
> 
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  mm/swapfile.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index e59e08ef46e1..21c88b0944f9 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -2103,15 +2103,18 @@ static int unuse_mm(struct mm_struct *mm, unsigned int type,
>  {
>  	struct vm_area_struct *vma;
>  	int ret = 0;
> +	MA_STATE(mas, &mm->mm_mt, 0, 0);
>  
>  	mmap_read_lock(mm);
> -	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> +	mas_for_each(&mas, vma, ULONG_MAX) {
>  		if (vma->anon_vma) {
>  			ret = unuse_vma(vma, type, frontswap,
>  					fs_pages_to_unuse);
>  			if (ret)
>  				break;
>  		}
> +
> +		mas_pause(&mas);

AFAIU unnecessary for the resched as we don't drop anything and keep the
mmap_lock?
(and without that it could be VMA_ITERATOR?)

>  		cond_resched();
>  	}
>  	mmap_read_unlock(mm);