mm: list_lru: disable memcg_aware when cgroup.memory is set to "nokmem"

Actually, when using a boot time kernel option "cgroup.memory=nokmem", all
lru items are inserted to list_lru_node.  But for those users who invoke
list_lru_init_memcg() to initialize list_lru, list_lru_memcg_aware()
returns true.  And this brings unneeded operations related to memcg.

To make things more convenient, let's disable memcg_aware when
cgroup.memory is set to "nokmem".

Link: https://lkml.kernel.org/r/20231228062715.338672-1-haifeng.xu@shopee.comSigned-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/list_lru.c

@@ -567,6 +567,9 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware,
 		lru->shrinker_id = shrinker->id;
 	else
 		lru->shrinker_id = -1;
+
+	if (mem_cgroup_kmem_disabled())
+		memcg_aware = false;
 #endif
 
 	lru->node = kcalloc(nr_node_ids, sizeof(*lru->node), GFP_KERNEL);