The only user is cgwb_bdi_init and that one depends on CONFIG_CGROUP_WRITEBACK which in turn depends on CONFIG_MEMCG so it doesn't make much sense to definte an empty stub for !CONFIG_MEMCG. Moreover ERR_PTR(-EINVAL) is ugly and would lead to runtime crashes if used in unguarded code paths. Better fail during compilation. Reviewed-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Signed-off-by: Michal Hocko <mhocko@xxxxxxxxxx> --- include/linux/memcontrol.h | 2 -- 1 file changed, 2 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 42f118ae04cf..292e6701f3fd 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -497,8 +497,6 @@ void mem_cgroup_split_huge_fixup(struct page *head); #else /* CONFIG_MEMCG */ struct mem_cgroup; -#define mem_cgroup_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL)) - static inline void mem_cgroup_events(struct mem_cgroup *memcg, enum mem_cgroup_events_index idx, unsigned int nr) -- 2.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>