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

[Baolin Wang <baolin.wang@linux.alibaba.com>]

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@linux.alibaba.com>
>> ---
>>   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.