Re: [v7 11/16] mm/migrate_device: add THP splitting during migration

[Balbir Singh]

On 2/10/26 03:00, David Hildenbrand (Arm) wrote:
> 
>> index 8c95a658b3ec..022b0729f826 100644
>> --- a/mm/huge_memory.c
>> +++ b/mm/huge_memory.c
>> @@ -3463,15 +3463,6 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
>>           new_folio->mapping = folio->mapping;
>>           new_folio->index = folio->index + i;
>>   -        /*
>> -         * page->private should not be set in tail pages. Fix up and warn once
>> -         * if private is unexpectedly set.
>> -         */
>> -        if (unlikely(new_folio->private)) {
>> -            VM_WARN_ON_ONCE_PAGE(true, new_head);
>> -            new_folio->private = NULL;
>> -        }
>> -
> 
> Balbir, why did you drop this check?
> 

Are we running into this somewhere? This change clearly seems unrelated to the intent of the
patch that made this change (by me). I was seeing new_folio->private as NULL everywhere during
my testing and so I removed the check, happy to bring this defensive test back.

Balbir