Re: [PATCH v2] mm/migrate: rename PAGE_ migration flags to FOLIO_

["Garg, Shivank" <shivankg@amd.com>]

>>
>>  static void __migrate_folio_record(struct folio *dst,
>> -				   int old_page_state,
>> +				   int old_folio_state,
>>  				   struct anon_vma *anon_vma)
>>  {
>> -	dst->private = (void *)anon_vma + old_page_state;
>> +	dst->private = (void *)anon_vma + old_folio_state;
>>  }
>>
>>  static void __migrate_folio_extract(struct folio *dst,
>> -				   int *old_page_state,
>> +				   int *old_folio_state,
>>  				   struct anon_vma **anon_vmap)
>>  {
>>  	unsigned long private = (unsigned long)dst->private;
>>
>> -	*anon_vmap = (struct anon_vma *)(private & ~PAGE_OLD_STATES);
>> -	*old_page_state = private & PAGE_OLD_STATES;
>> +	*anon_vmap = (struct anon_vma *)(private & ~FOLIO_OLD_STATES);
>> +	*old_folio_state = private & FOLIO_OLD_STATES;
>>  	dst->private = NULL;
>>  }
> 
> Just an observation on folio->private, it is void*, but page->private
> is unsigned long. It confused me a bit. There are folio_get_private()
> and folio_change_private(), I wonder if we want to use them here
> instead of direct ->private accesses. Feel free to ignore this,
> since it is irrelevant to this patch.

Would something like this as a follow-up patch work?

diff --git a/mm/migrate.c b/mm/migrate.c
index 6d4a85f903d8..55d1af6c9759 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1143,17 +1143,17 @@ enum {
 static void __migrate_folio_record(struct folio *dst,
 		int old_folio_state, struct anon_vma *anon_vma)
 {
-	dst->private = (void *)anon_vma + old_folio_state;
+	folio_change_private(dst, (void *)anon_vma + old_folio_state);
 }
 
 static void __migrate_folio_extract(struct folio *dst,
 		int *old_folio_state, struct anon_vma **anon_vmap)
 {
-	unsigned long private = (unsigned long)dst->private;
+	unsigned long private = (unsigned long)folio_get_private(dst);
 
 	*anon_vmap = (struct anon_vma *)(private & ~FOLIO_OLD_STATES);
 	*old_folio_state = private & FOLIO_OLD_STATES;
-	dst->private = NULL;
+	folio_change_private(dst, NULL);
 }
 

Thanks,
Shivank