mm/memcg: set pos explicitly for reclaim and !reclaim
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.
Link: https://lkml.kernel.org/r/20220330234719.18340-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f06b5c2..1b76d56 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1013,9 +1013,6 @@ 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) {
@@ -1041,6 +1038,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
*/
(void)cmpxchg(&iter->position, pos, NULL);
}
+ } else if (prev) {
+ pos = prev;
}
if (pos)
