Re: [Patch v3 2/4] mm/migrate.c: wrap do_move_pages_to_node() and store_status()

From: Michal Hocko
Date: Mon Jan 27 2020 - 04:36:47 EST


On Sun 26-01-20 18:26:21, Wei Yang wrote:
> Usually do_move_pages_to_node() and store_status() is a pair. There are
> three places call this pair of functions with almost the same form.
>
> This patch just wrap it to make it friendly to audience and also
> consolidate the move and store action into one place.
>
> Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>

I believe I have already acked this one. Anyway
Acked-by: Michal Hocko <mhocko@xxxxxxxx>

> ---
> mm/migrate.c | 61 ++++++++++++++++++++++++++--------------------------
> 1 file changed, 30 insertions(+), 31 deletions(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index ae3db45c6a42..e816c8990296 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1583,6 +1583,29 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
> return err;
> }
>
> +static int move_pages_and_store_status(struct mm_struct *mm, int node,
> + struct list_head *pagelist, int __user *status,
> + unsigned long nr_pages, int start, int i)
> +{
> + int err;
> +
> + err = do_move_pages_to_node(mm, pagelist, node);
> + 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;
> + return err;
> + }
> + err = store_status(status, start, node, i - start);
> + return err;
> +}
> +
> /*
> * Migrate an array of page address onto an array of nodes and fill
> * the corresponding array of status.
> @@ -1626,20 +1649,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
> current_node = node;
> start = i;
> } else if (node != current_node) {
> - err = do_move_pages_to_node(mm, &pagelist, current_node);
> - 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);
> + err = move_pages_and_store_status(mm, current_node,
> + &pagelist, status, nr_pages,
> + start, i);
> if (err)
> goto out;
> start = i;
> @@ -1668,13 +1680,8 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
> if (err)
> goto out_flush;
>
> - err = do_move_pages_to_node(mm, &pagelist, current_node);
> - if (err) {
> - if (err > 0)
> - err += nr_pages - i - 1;
> - goto out;
> - }
> - err = store_status(status, start, current_node, i - start);
> + err = move_pages_and_store_status(mm, current_node, &pagelist,
> + status, nr_pages, start, i);
> if (err)
> goto out;
> current_node = NUMA_NO_NODE;
> @@ -1684,16 +1691,8 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
> return err;
>
> /* 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:
> - * - 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);
> + err1 = move_pages_and_store_status(mm, current_node, &pagelist,
> + status, nr_pages, start, i);
> if (err >= 0)
> err = err1;
> out:
> --
> 2.17.1

--
Michal Hocko
SUSE Labs