For each round-trip, we assign generation on first invocation and
compare it on subsequent invocations.
Let's move them together to make it more self-explaining. Also this
reduce a check on prev.
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
---
mm/memcontrol.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 03399146168f..17da93c2f94e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -996,7 +996,14 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
mz = root->nodeinfo[reclaim->pgdat->node_id];
iter = &mz->iter;
- if (prev && reclaim->generation != iter->generation)
+ /*
+ * On first invocation, assign iter->generation to
+ * reclaim->generation.
+ * On subsequent invocations, make sure no one else jump in.
+ */
+ if (!prev)
+ reclaim->generation = iter->generation;
+ else if (reclaim->generation != iter->generation)
goto out_unlock;
while (1) {
@@ -1056,8 +1063,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
if (!memcg)
iter->generation++;
- else if (!prev)
- reclaim->generation = iter->generation;
}
out_unlock:
--
2.33.1
