The page only can be marked as kmem when CONFIG_MEMCG_KMEM is enabled. So move PageMemcgKmem() to the scope of the CONFIG_MEMCG_KMEM.
As a bonus, on !CONFIG_MEMCG_KMEM build some code can be compiled out. Signed-off-by: Muchun Song <songmuc...@bytedance.com> Acked-by: Roman Gushchin <g...@fb.com> Reviewed-by: Shakeel Butt <shake...@google.com> Acked-by: Johannes Weiner <han...@cmpxchg.org> --- include/linux/memcontrol.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 395a113e4a3b..7fdc92e1983e 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -510,6 +510,7 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page) return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); } +#ifdef CONFIG_MEMCG_KMEM /* * PageMemcgKmem - check if the page has MemcgKmem flag set * @page: a pointer to the page struct @@ -524,7 +525,6 @@ static inline bool PageMemcgKmem(struct page *page) return page->memcg_data & MEMCG_DATA_KMEM; } -#ifdef CONFIG_MEMCG_KMEM /* * page_objcgs - get the object cgroups vector associated with a page * @page: a pointer to the page struct @@ -566,6 +566,11 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page) } #else +static inline bool PageMemcgKmem(struct page *page) +{ + return false; +} + static inline struct obj_cgroup **page_objcgs(struct page *page) { return NULL; -- 2.11.0