On Thu, Jan 23, 2020 at 03:36:58PM -0800, Yang Shi wrote:
>
>
>On 1/23/20 2:59 PM, Wei Yang wrote:
>> On Thu, Jan 23, 2020 at 07:38:51AM +0800, Yang Shi wrote:
>> > Since commit a49bd4d71637 ("mm, numa: rework do_pages_move"),
>> > the semantic of move_pages() was changed to return the number of
>> > non-migrated pages (failed to migration) and the call would be aborted
>> > immediately if migrate_pages() returns positive value. But it didn't
>> > report the number of pages that we even haven't attempted to migrate.
>> > So, fix it by including non-attempted pages in the return value.
>> >
>> > Fixes: a49bd4d71637 ("mm, numa: rework do_pages_move")
>> > Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
>> > Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>> > Cc: <stable@xxxxxxxxxxxxxxx> [4.17+]
>> > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
>> > ---
>> > v2: Rebased on top of the latest mainline kernel per Andrew
>> >
>> > mm/migrate.c | 24 ++++++++++++++++++++++--
>> > 1 file changed, 22 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/mm/migrate.c b/mm/migrate.c
>> > index 86873b6..9b8eb5d 100644
>> > --- a/mm/migrate.c
>> > +++ b/mm/migrate.c
>> > @@ -1627,8 +1627,18 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>> > start = i;
>> > } else if (node != current_node) {
>> > err = do_move_pages_to_node(mm, &pagelist, current_node);
>> > - if (err)
>> > + if (err) {
>> > + /*
>> > + * Positive err means the number of failed
>> > + * pages to migrate. Since we are going to
>> > + * abort and return the number of non-migrated
>> > + * pages, so need incude the rest of the
>> > + * nr_pages that have not attempted as well.
>> > + */
>> > + if (err > 0)
>> > + err += nr_pages - i - 1;
>> > goto out;
>> > + }
>> > err = store_status(status, start, current_node, i - start);
>> > if (err)
>> > goto out;
>> > @@ -1659,8 +1669,11 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>> > goto out_flush;
>> >
>> > err = do_move_pages_to_node(mm, &pagelist, current_node);
>> > - if (err)
>> > + if (err) {
>> > + if (err > 0)
>> > + err += nr_pages - i - 1;
>> > goto out;
>> > + }
>> > if (i > start) {
>> > err = store_status(status, start, current_node, i - start);
>> > if (err)
>> > @@ -1674,6 +1687,13 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>> >
>> > /* Make sure we do not overwrite the existing error */
>> > err1 = do_move_pages_to_node(mm, &pagelist, current_node);
>> > + /*
>> > + * Don't have to report non-attempted pages here since:
>> In previous comment, you use "non-migrated". Here is "non-attempted". What's
>> the difference?
>
>In that comment "non-migrated" includes both reported by migrate_pages() and
>the non-attempted.
>
ok, I see the difference.
>>
>> > + * - If the above loop is done gracefully there is not non-attempted
>> > + * page.
>> > + * - If the above loop is aborted to it means more fatal error
>> > + * happened, should return err.
>> > + */
>> > if (!err1)
>> > err1 = store_status(status, start, current_node, i - start);
>> > if (!err)
>> > --
>> > 1.8.3.1
--
Wei Yang
Help you, Help me
