From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Subject: mm/migrate.c: unify "not queued for migration" handling in do_pages_move() It can currently happen that we store the status of a page twice: * Once we detect that it is already on the target node * Once we moved a bunch of pages, and a page that's already on the target node is contained in the current interval. Let's simplify the code and always call do_move_pages_to_node() in case we did not queue a page for migration. Note that pages that are already on the target node are not added to the pagelist and are, therefore, ignored by do_move_pages_to_node() - there is no functional change. The status of such a page is now only stored once. [david@xxxxxxxxxx rephrase changelog] Link: http://lkml.kernel.org/r/20200214003017.25558-5-richardw.yang@xxxxxxxxxxxxxxx Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/migrate.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) --- a/mm/migrate.c~mm-migratec-unify-not-queued-for-migration-handling-in-do_pages_move +++ a/mm/migrate.c @@ -1683,18 +1683,16 @@ static int do_pages_move(struct mm_struc err = add_page_for_migration(mm, addr, current_node, &pagelist, flags & MPOL_MF_MOVE_ALL); - if (!err) { - /* The page is already on the target node */ - err = store_status(status, i, current_node, 1); - if (err) - goto out_flush; - continue; - } else if (err > 0) { + if (err > 0) { /* The page is successfully queued for migration */ continue; } - err = store_status(status, i, err, 1); + /* + * If the page is already on the target node (!err), store the + * node, otherwise, store the err. + */ + err = store_status(status, i, err ? : current_node, 1); if (err) goto out_flush; _
