We never charge the page counters of root memcg, so there is no need to put root memcg in the memcg stock. At the moment, refill_stock() can be called from try_charge_memcg(), obj_cgroup_uncharge_pages() and mem_cgroup_uncharge_skmem(). The try_charge_memcg() and mem_cgroup_uncharge_skmem() are never called with root memcg, so those are fine. However obj_cgroup_uncharge_pages() can potentially call refill_stock() with root memcg if the objcg object has been reparented over to the root memcg. Let's just avoid refill_stock() from obj_cgroup_uncharge_pages() for root memcg. Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx> --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e08ce52caabd..393b73aec6dd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2643,7 +2643,8 @@ static void obj_cgroup_uncharge_pages(struct obj_cgroup *objcg, mod_memcg_state(memcg, MEMCG_KMEM, -nr_pages); memcg1_account_kmem(memcg, -nr_pages); - refill_stock(memcg, nr_pages); + if (!mem_cgroup_is_root(memcg)) + refill_stock(memcg, nr_pages); css_put(&memcg->css); } -- 2.47.1
