Re: [PATCH] mm/khugepaged: continue to collapse on SCAN_PMD_NONE

["David Hildenbrand (Red Hat)" <david@kernel.org>]

On 12.11.25 10:51, David Hildenbrand (Red Hat) wrote:
> On 12.11.25 03:00, Wei Yang wrote:
>> SCAN_PMD_NONE means current pmd is empty, but we can still continue
>> collapse next pmd range.
>>
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>> ---
>>    mm/khugepaged.c | 1 +
>>    1 file changed, 1 insertion(+)
>>
>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>> index 7e8cb181d5bd..4c2217076ad3 100644
>> --- a/mm/khugepaged.c
>> +++ b/mm/khugepaged.c
>> @@ -2835,6 +2835,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start,
>>    			goto handle_result;
>>    		/* Whitelisted set of results where continuing OK */
>>    		case SCAN_PMD_NULL:
>> +		case SCAN_PMD_NONE:
>>    		case SCAN_PTE_NON_PRESENT:
>>    		case SCAN_PTE_UFFD_WP:
>>    		case SCAN_LACK_REFERENCED_PAGE:
> 
> Looks ok to me.
> 
> I am really confused about PMD_NONE vs. PMD_NULL.
> 
> Is my understanding correct, hat with your patch we can just merge both
> into a single NO_PMD_TABLE or sth. like that?

NO_PTE_TABLE, actually

-- 
Cheers

David