[Patch v2 2/3] mm/memcg: set pos explicitly for reclaim and !reclaim

[Wei Yang <richard.weiyang@gmail.com>]

During mem_cgroup_iter, there are two ways to get iteration position:
reclaim vs non-reclaim mode.

Let's do it explicitly for reclaim vs non-reclaim mode.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>

---
v2: split into two explicit part as suggested by Johannes
---
 mm/memcontrol.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eed9916cdce5..5d433b79ba47 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1005,9 +1005,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 	if (!root)
 		root = root_mem_cgroup;
 
-	if (prev && !reclaim)
-		pos = prev;
-
 	rcu_read_lock();
 
 	if (reclaim) {
@@ -1033,6 +1030,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 			 */
 			(void)cmpxchg(&iter->position, pos, NULL);
 		}
+	} else if (prev) {
+		pos = prev;
 	}
 
 	if (pos)
-- 
2.33.1