[PATCH v3 4/4] mm: memcontrol: move PageMemcgKmem to the scope of CONFIG_MEMCG_KMEM

[Muchun Song <songmuchun@bytedance.com>]

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 <songmuchun@bytedance.com>
---
 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 07c449af9c0f..d3ca8c8e7fc3 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -469,6 +469,7 @@ 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
@@ -483,7 +484,6 @@ 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
@@ -544,6 +544,11 @@ static inline struct obj_cgroup *page_objcg(struct page *page)
 	return (struct obj_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
 }
 #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