[Patch v3 3/4] mm/migrate.c: check pagelist in move_pages_and_store_status()

From: Wei Yang
Date: Sun Jan 26 2020 - 05:27:26 EST


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@xxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
mm/migrate.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index e816c8990296..b123ced445b7 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1499,9 +1499,6 @@ 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)
@@ -1589,6 +1586,9 @@ 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) {
/*
@@ -1687,9 +1687,6 @@ 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, nr_pages, start, i);
--
2.17.1