Re: [PATCH] mm/migrate: Continue to migrate for small pages

[Chen Wandun]

On 2023/1/29 11:01, Huang, Ying wrote:
> Chen Wandun <chenwandun@xxxxxxxxxx> writes:
>
> > migrate_hugetlbs returns -ENOMEM when no enough huge page,
> > however maybe there are still free small pages, so continue
> > to migrate for small pages.
> Better to replace "page" with "folio", and "small" with "non-hugetlb".
Will do.
> > Signed-off-by: Chen Wandun <chenwandun@xxxxxxxxxx>
> > ---
> >   mm/migrate.c | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/migrate.c b/mm/migrate.c
> > index b971edbf32fc..c9d0d2058036 100644
> > --- a/mm/migrate.c
> > +++ b/mm/migrate.c
> > @@ -1939,7 +1939,12 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
> >   
> >   	rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private,
> >   				     mode, reason, &stats, &ret_folios);
> > -	if (rc_gather < 0)
> > +	/* Maybe there are free small pages, continue to migrate.
> There may be free non-hugetlb folios available, continue to migrate.
will do
> > +	 * Nowdays the only negtive return value of migrate_hugetlbs
> > +	 * is -ENOMEM, keep compatible for coming negtive return
> > +	 * value instead of ignore return value.
> This can be moved to patch description.
will do
thanks for your review.

Best Regards.
Wandun
> > +	 */
> > +	if (rc_gather < 0 && rc_gather != -ENOMEM)
> >   		goto out;
> >   again:
> >   	nr_pages = 0;
> Best Regards,
> Huang, Ying
> .