Re: [PATCH -V8 04/10] mm/migrate: make migrate_pages() return nr_succeeded

[Huang, Ying]

Oscar Salvador <osalvador@xxxxxxx> writes:

> On Fri, Jun 18, 2021 at 02:15:31PM +0800, Huang Ying wrote:
>> From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
>> 
>> The migrate_pages() returns the number of pages that were not migrated,
>> or an error code.  When returning an error code, there is no way to know
>> how many pages were migrated or not migrated.
>> 
>> In the following patch, migrate_pages() is used to demote pages to PMEM
>> node, we need account how many pages are reclaimed (demoted) since page
>> reclaim behavior depends on this.  Add *nr_succeeded parameter to make
>> migrate_pages() return how many pages are demoted successfully for all
>> cases.
>> 
>> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
>> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>> Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
>> Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Wei Xu <weixugc@xxxxxxxxxx>
>> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> Cc: David Hildenbrand <david@xxxxxxxxxx>
>> Cc: osalvador <osalvador@xxxxxxx>
>
> I thought we all agreed on making nr_succeed an optional argument [1].
> It reduced the churn quite a lot.
>
> [1] https://patchwork.kernel.org/comment/24104453/

Sorry.  Forget changing this.  Will change it in the next version.

Best Regards,
Huang, Ying