Re: [v4 05/15] mm/migrate_device: handle partially mapped folios during collection

[Balbir Singh]

On 9/3/25 14:40, Mika Penttilä wrote:
> Hi,
> 
> On 9/3/25 04:18, Balbir Singh wrote:
> 
>> Extend migrate_vma_collect_pmd() to handle partially mapped large
>> folios that require splitting before migration can proceed.
>>
>> During PTE walk in the collection phase, if a large folio is only
>> partially mapped in the migration range, it must be split to ensure
>> the folio is correctly migrated.
>>

<snip>

>> +
>> +				/*
>> +				 * The reason for finding pmd present with a
>> +				 * large folio for the pte is partial unmaps.
>> +				 * Split the folio now for the migration to be
>> +				 * handled correctly
>> +				 */
> 
> There are other reasons like vma splits for various reasons.
> 

Yes, David had pointed that out as well, I meant to cleanup the comment change
"The" to "One", I missed addressing it in the refactor, but easy to do

Thanks,
Balbir Singh