Re: [PATCH 2/2] mm: shmem: fix the update of 'shmem_falloc->nr_unswapped'

[David Hildenbrand]

On 19.12.24 08:30, Baolin Wang wrote:
> The 'shmem_falloc->nr_unswapped' is used to record how many writepage
> refused to swap out because fallocate() is allocating, but after shmem
> supports large folio swap out, the update of 'shmem_falloc->nr_unswapped'
> does not use the correct number of pages in the large folio, which may
> lead to fallocate() not exiting as soon as possible.
>
> Anyway, this is found through code inspection, and I am not sure whether
> it would actually cause serious issues.
>
> Fixes: 809bc86517cc ("mm: shmem: support large folio swap out")
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> ---
>   mm/shmem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index dec659e84562..ac58d4fb2e6f 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1535,7 +1535,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
>   			    !shmem_falloc->waitq &&
>   			    index >= shmem_falloc->start &&
>   			    index < shmem_falloc->next)
> -				shmem_falloc->nr_unswapped++;
> +				shmem_falloc->nr_unswapped += nr_pages;
>   			else
>   				shmem_falloc = NULL;
>   			spin_unlock(&inode->i_lock);

Acked-by: David Hildenbrand <david@xxxxxxxxxx>


--
Cheers,

David / dhildenb