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?
>+ * - 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
