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

[Baolin Wang]

On 2024/6/10 22:53, Daniel Gomez wrote:
> 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()

OK. Will do.