Re: [PATCH 1/2] mm/huge_memory: introduce __split_folio_and_update_stats() to consolidate split task

[Wei Yang <richard.weiyang@gmail.com>]

On Mon, Nov 03, 2025 at 05:20:02PM +0100, David Hildenbrand (Red Hat) wrote:
>On 01.11.25 01:29, Wei Yang wrote:
>> The folio splitting process involves several related tasks that are
>> executed together:
>> 
>>      Adjusting memcg (memory control group) accounting.
>>      Updating page owner tracking.
>>      Splitting the folio to the target size (new_order).
>>      Updating necessary folio statistics.
>> 
>> This commit introduces the new helper function,
>> __split_folio_and_update_stats(), to gather all these tasks. This
>> consolidation improves modularity and is a necessary preparation step
>> for further cleanup and simplification of the surrounding folio
>> splitting logic.
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>> Cc: Zi Yan <ziy@nvidia.com>
>> ---
>>   mm/huge_memory.c | 28 +++++++++++++++++-----------
>>   1 file changed, 17 insertions(+), 11 deletions(-)
>> 
>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>> index c37fe6ad0c96..abde0f1aa8ff 100644
>> --- a/mm/huge_memory.c
>> +++ b/mm/huge_memory.c
>> @@ -3567,6 +3567,22 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
>>   		ClearPageCompound(&folio->page);
>>   }
>> +static void __split_folio_and_update_stats(struct folio *folio, int old_order,
>> +		int new_order, bool is_anon)
>
>Is there any good reason we want to pass things like "is_anon" instead of
>just querying it in that helper?
>

The reason is during split, folio's attribute will not change. In
__split_unmapped_folio() it is queried and set as const.

Otherwise we need to query it on each split.

>
>> +{
>> +	int nr_new_folios = 1UL << (old_order - new_order);
>
>Could be const.
>

Will add it.

>
>-- 
>Cheers
>
>David

-- 
Wei Yang
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