mem_cgroup_id_get_many() is currently used only when MMU or MEMCG_SWAP configuration options are enabled. Having them disabled triggers the following warning at compile time: linux/mm/memcontrol.c:4797:13: warning: ‘mem_cgroup_id_get_many’ defined but not used [-Wunused-function] static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) Make mem_cgroup_id_get_many() dependent on MMU and MEMCG_SWAP to address the issue. Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d09776cd6e10..628cebeb4bdd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4794,10 +4794,12 @@ static void mem_cgroup_id_remove(struct mem_cgroup *memcg) } } +#if defined(CONFIG_MEMCG_SWAP) || defined(CONFIG_MMU) static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n) { refcount_add(n, &memcg->id.ref); } +#endif static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n) { -- 2.25.1