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

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

On Tue, Nov 04, 2025 at 11:33:43AM +0100, David Hildenbrand (Red Hat) wrote:
>On 04.11.25 00:37, Wei Yang wrote:
>> 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.
>
>These checks are extremely cheap. Do we really care?
>

Ok, will remove it.

>-- 
>Cheers
>
>David

-- 
Wei Yang
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