mm/migrate.c: check pagelist in move_pages_and_store_status()

When pagelist is empty, it is not necessary to do the move and store.
Also it consolidate the empty list check in one place.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200214003017.25558-4-richardw.yang@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index 6f6317903007c4e53f6bc38a5663f8e868235b25..80eaa99bed398890d8f27048031576f407bc6cb5 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1518,9 +1518,6 @@ static int do_move_pages_to_node(struct mm_struct *mm,
 {
        int err;
 
-       if (list_empty(pagelist))
-               return 0;
-
        err = migrate_pages(pagelist, alloc_new_node_page, NULL, node,
                        MIGRATE_SYNC, MR_SYSCALL);
        if (err)
@@ -1608,6 +1605,9 @@ static int move_pages_and_store_status(struct mm_struct *mm, int node,
 {
        int err;
 
+       if (list_empty(pagelist))
+               return 0;
+
        err = do_move_pages_to_node(mm, pagelist, node);
        if (err) {
                /*
@@ -1705,9 +1705,6 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
                current_node = NUMA_NO_NODE;
        }
 out_flush:
-       if (list_empty(&pagelist))
-               return err;
-
        /* Make sure we do not overwrite the existing error */
        err1 = move_pages_and_store_status(mm, current_node, &pagelist,
                                status, start, i, nr_pages);