With cgroup.memory=nokmem, __list_lru_init() collapses every list_lru into per-node lists. That is fine for slab objects, which are not charged per memcg without kmem accounting. But a lru backed by a SHRINKER_NONSLAB shrinker, e.g. the THP deferred split queue or the zswap entries, holds user memory, which is charged regardless of nokmem. Collapsing such an lru loses the per-memcg view of its objects. Reclaim can no longer target just the cgroup under pressure. Keep such lrus memcg aware under nokmem when their backing shrinker is registered SHRINKER_NONSLAB. This leaves the savings of nokmem intact: slab-backed lrus (e.g. the superblock dentry/inode lrus) still fall back to the per-node lists, and the per-memcg lists are allocated only when a memcg actually holds such objects. Fixes: fafaeceb89a5 ("mm: switch deferred split shrinker to list_lru") Signed-off-by: Qinyun Tan Reviewed-by: Johannes Weiner --- mm/list_lru.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 9241d17de4388..d20faa6de6c02 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -672,7 +672,9 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware, struct shrinker *shr else lru->shrinker_id = -1; - if (mem_cgroup_disabled() || mem_cgroup_kmem_disabled()) + if (mem_cgroup_disabled() || + (mem_cgroup_kmem_disabled() && + (!shrinker || !(shrinker->flags & SHRINKER_NONSLAB)))) memcg_aware = false; #endif -- 2.43.7