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.
[hannes@xxxxxxxxxxx: better comment to explain reclaim model]
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
v2: a better comment from Johannes
---
mm/memcontrol.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5d433b79ba47..2cd8bfdec379 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1013,7 +1013,13 @@ 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 start, join the current reclaim iteration cycle.
+ * Exit when a concurrent walker completes it.
+ */
+ if (!prev)
+ reclaim->generation = iter->generation;
+ else if (reclaim->generation != iter->generation)
goto out_unlock;
while (1) {
@@ -1075,8 +1081,6 @@ 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
