Re: [PATCH 2/2] mm/migrate_device: further convert migrate_device_finalize() to folios

[Sidhartha Kumar]

On 2/14/24 2:45 PM, Alistair Popple wrote:
> Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> writes:
>
> > Use folio api functions from the already defined src and dst folio
> > variables.
> >
> > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> > ---
> >   mm/migrate_device.c | 14 +++++++-------
> >   1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/mm/migrate_device.c b/mm/migrate_device.c
> > index 9152a329b0a68..a48d5cdb28553 100644
> > --- a/mm/migrate_device.c
> > +++ b/mm/migrate_device.c
> > @@ -843,17 +843,17 @@ void migrate_device_finalize(unsigned long *src_pfns,
> >   		remove_migration_ptes(src, dst, false);
> >   		folio_unlock(src);
> >   
> > -		if (is_zone_device_page(page))
> > -			put_page(page);
> > +		if (folio_is_zone_device(src))
> > +			folio_put(src);
> >   		else
> > -			putback_lru_page(page);
> > +			folio_putback_lru(src);
> >   
> >   		if (newpage != page) {
> > -			unlock_page(newpage);
> > -			if (is_zone_device_page(newpage))
> > -				put_page(newpage);
>
> Defining migrate_pfn_to_folio() would also allow the removal of the
> newpage and page variables entirely which I think would make this
> clearer.
>
> As an aside is there any motivation for making these changes other than
> as a general cleanup? I ask only because I have been looking at allowing
> device pages with order > 0 so have some of these clean-ups in a local
> tree as they're a pre-requisite for that.
>
>   - Alistair

Hello,

The motivation is just general cleanup. In folio-compat.c I saw that 
putback_lru_page() does not have much users left so I could convert them and 
then just get rid of putback_lru_page(). Should I still continue with a v2 that 
will include defining a migrate_pfn_to_folio() or wait for your clean-ups?

Thanks,
Sid

> > +			folio_unlock(dst);
> > +			if (folio_is_zone_device(dst))
> > +				folio_put(dst);
> >   			else
> > -				putback_lru_page(newpage);
> > +				folio_putback_lru(dst);
> >   		}
> >   	}
> >   }