Re: [PATCH V2 2/2] mm/khugepaged: map dirty/writeback pages failures to EAGAIN

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

On 11/20/25 13:24, Lance Yang wrote:
> 
> 
> On 2025/11/20 16:17, Garg, Shivank wrote:
>>
>>
>> On 11/20/2025 1:33 PM, Dev Jain wrote:
>>>
>>> On 20/11/25 12:20 pm, Shivank Garg wrote:
>>
>>> SCAN_PAGE_NOT_CLEAN is confusing - NOT_CLEAN literally means dirty, so why not SCAN_PAGE_DIRTY?
>>> Or SCAN_PAGE_DIRTY_OR_UNDER_WRITEBACK? Since folio_test_writeback() is true as a result of
>>> the folio being dirty, maybe just SCAN_PAGE_DIRTY can do.
>>>
>>> Reviewed-by: Dev Jain <dev.jain@arm.com>
>>>
>> Thanks for the review.
>>
>> I chose not to use SCAN_PAGE_DIRTY because dirty and writeback have different meanings[1]:
>>
>>       Dirty: Memory that is waiting to be written back to disk
>> Writeback: Memory that is actively being written back to disk
>>
>> [1] https://www.kernel.org/doc/Documentation/filesystems/proc.txt
>>
>> IIUC, a page under writeback is no longer dirty, so using SCAN_PAGE_DIRTY would be misleading
>> for pages in the writeback state.
>>
>> I considered SCAN_PAGE_DIRTY_OR_WRITEBACK initially but felt it was too long.
> 
> Nit: If SCAN_PAGE_DIRTY_OR_WRITEBACK 

I would prefer that here.

-- 
Cheers

David