[PATCH v2 1/6] mm: kmem: cleanup (__)memcg_kmem_charge_memcg() arguments

[Roman Gushchin <guro@fb.com>]

The first argument of memcg_kmem_charge_memcg() and
__memcg_kmem_charge_memcg() is the page pointer and it's not used.
Let's drop it.

Memcg pointer is passed as the last argument. Move it to
the first place for consistency with other memcg functions,
e.g. __memcg_kmem_uncharge_memcg() or try_charge().

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 include/linux/memcontrol.h | 9 ++++-----
 mm/memcontrol.c            | 8 +++-----
 mm/slab.h                  | 2 +-
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a7a0a1a5c8d5..c954209fd685 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1364,8 +1364,7 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep);
 #ifdef CONFIG_MEMCG_KMEM
 int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
 void __memcg_kmem_uncharge(struct page *page, int order);
-int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
-			      struct mem_cgroup *memcg);
+int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp, int order);
 void __memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
 				 unsigned int nr_pages);
 
@@ -1402,11 +1401,11 @@ static inline void memcg_kmem_uncharge(struct page *page, int order)
 		__memcg_kmem_uncharge(page, order);
 }
 
-static inline int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp,
-					  int order, struct mem_cgroup *memcg)
+static inline int memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp,
+					  int order)
 {
 	if (memcg_kmem_enabled())
-		return __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+		return __memcg_kmem_charge_memcg(memcg, gfp, order);
 	return 0;
 }
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c5b5f74cfd4d..6ef38f669923 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2820,15 +2820,13 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep)
 
 /**
  * __memcg_kmem_charge_memcg: charge a kmem page
- * @page: page to charge
+ * @memcg: memory cgroup to charge
  * @gfp: reclaim mode
  * @order: allocation order
- * @memcg: memory cgroup to charge
  *
  * Returns 0 on success, an error code on failure.
  */
-int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
-			    struct mem_cgroup *memcg)
+int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp, int order)
 {
 	unsigned int nr_pages = 1 << order;
 	struct page_counter *counter;
@@ -2874,7 +2872,7 @@ int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 
 	memcg = get_mem_cgroup_from_current();
 	if (!mem_cgroup_is_root(memcg)) {
-		ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+		ret = __memcg_kmem_charge_memcg(memcg, gfp, order);
 		if (!ret) {
 			page->mem_cgroup = memcg;
 			__SetPageKmemcg(page);
diff --git a/mm/slab.h b/mm/slab.h
index 7e94700aa78c..c4c93e991250 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -365,7 +365,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 		return 0;
 	}
 
-	ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
+	ret = memcg_kmem_charge_memcg(memcg, gfp, order);
 	if (ret)
 		goto out;
 
-- 
2.21.1