Re: [PATCH 4/7] mm: shmem: extend shmem_partial_swap_usage() to support large folio swap

[Daniel Gomez]

Hi Baolin,
On Thu, Jun 06, 2024 at 07:58:54PM +0800, Baolin Wang wrote:
> To support shmem large folio swapout in the following patches, using
> xa_get_order() to get the order of the swap entry to calculate the swap
> usage of shmem.
> 
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> ---
>  mm/shmem.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index eefdf5c61c04..0ac71580decb 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -865,13 +865,16 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
>  	struct page *page;
>  	unsigned long swapped = 0;
>  	unsigned long max = end - 1;
> +	int order;
>  
>  	rcu_read_lock();
>  	xas_for_each(&xas, page, max) {
>  		if (xas_retry(&xas, page))
>  			continue;
> -		if (xa_is_value(page))
> -			swapped++;
> +		if (xa_is_value(page)) {
> +			order = xa_get_order(xas.xa, xas.xa_index);
> +			swapped += 1 << order;

I'd get rid of order and simply do:

	swapped += 1UL << xa_get_order()


> +		}
>  		if (xas.xa_index == max)
>  			break;
>  		if (need_resched()) {
> -- 
> 2.39.3
>