swap.h: move memcg related stuff to the end of the file

The following patches will add more functions to the memcg section of
include/linux/swap.h.  Some of them will need values defined below the
current location of the section.  So let's move the section to the end of
the file.  No functional changes intended.

Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/swap.h

@@ -350,39 +350,7 @@ extern void check_move_unevictable_pages(struct page **, int nr_pages);
 
 extern int kswapd_run(int nid);
 extern void kswapd_stop(int nid);
-#ifdef CONFIG_MEMCG
-static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
-{
-	/* root ? */
-	if (mem_cgroup_disabled() || !memcg->css.parent)
-		return vm_swappiness;
-
-	return memcg->swappiness;
-}
 
-#else
-static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
-{
-	return vm_swappiness;
-}
-#endif
-#ifdef CONFIG_MEMCG_SWAP
-extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
-extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
-extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
-#else
-static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
-{
-}
-static inline int mem_cgroup_try_charge_swap(struct page *page,
-					     swp_entry_t entry)
-{
-	return 0;
-}
-static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
-{
-}
-#endif
 #ifdef CONFIG_SWAP
 /* linux/mm/page_io.c */
 extern int swap_readpage(struct page *);
@@ -561,5 +529,43 @@ static inline swp_entry_t get_swap_page(void)
 }
 
 #endif /* CONFIG_SWAP */
+
+#ifdef CONFIG_MEMCG
+static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
+{
+	/* root ? */
+	if (mem_cgroup_disabled() || !memcg->css.parent)
+		return vm_swappiness;
+
+	return memcg->swappiness;
+}
+
+#else
+static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+	return vm_swappiness;
+}
+#endif
+
+#ifdef CONFIG_MEMCG_SWAP
+extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
+extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry);
+extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
+#else
+static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+{
+}
+
+static inline int mem_cgroup_try_charge_swap(struct page *page,
+					     swp_entry_t entry)
+{
+	return 0;
+}
+
+static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
+{
+}
+#endif
+
 #endif /* __KERNEL__*/
 #endif /* _LINUX_SWAP_H */