In some situations, we may end up calling memcg_rstat_updated() with a
value of 0, which means the stat was not actually updated. An example is
if we fail to reclaim any pages in shrink_folio_list().
Do not add the cgroup to the rstat updated tree in this case, to avoid
unnecessarily flushing it.
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
mm/memcontrol.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 361c0bbf7283..a63ee2efa780 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -618,6 +618,9 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
{
unsigned int x;
+ if (!val)
+ return;
+
cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id());
x = __this_cpu_add_return(stats_updates, abs(val));
--
2.40.0.348.gf938b09366-goog
