[PATCH v2 4/6] mm: kmem: switch to nr_pages in (__)memcg_kmem_charge_memcg()

[Roman Gushchin <guro@fb.com>]

These functions are charging the given number of kernel pages to the
given memory cgroup. The number doesn't have to be a power of two.
Let's make them to take the unsigned int nr_pages as an argument
instead of the page order.

It makes them look consistent with the corresponding uncharge
functions and functions like: mem_cgroup_charge_skmem(memcg, nr_pages).

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 include/linux/memcontrol.h | 11 ++++++-----
 mm/memcontrol.c            |  8 ++++----
 mm/slab.h                  |  2 +-
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4ee0c345e905..851c373edb74 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1364,7 +1364,8 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep);
 #ifdef CONFIG_MEMCG_KMEM
 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order);
 void __memcg_kmem_uncharge_page(struct page *page, int order);
-int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp, int order);
+int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp,
+			      unsigned int nr_pages);
 void __memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
 				 unsigned int nr_pages);
 
@@ -1403,18 +1404,18 @@ static inline void memcg_kmem_uncharge_page(struct page *page, int order)
 }
 
 static inline int memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp,
-					  int order)
+					  unsigned int nr_pages)
 {
 	if (memcg_kmem_enabled())
-		return __memcg_kmem_charge_memcg(memcg, gfp, order);
+		return __memcg_kmem_charge_memcg(memcg, gfp, nr_pages);
 	return 0;
 }
 
 static inline void memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
-					     int order)
+					     unsigned int nr_pages)
 {
 	if (memcg_kmem_enabled())
-		__memcg_kmem_uncharge_memcg(memcg, 1 << order);
+		__memcg_kmem_uncharge_memcg(memcg, nr_pages);
 }
 
 /*
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6bdf040e4615..8dbfb9fed9d8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2822,13 +2822,13 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep)
  * __memcg_kmem_charge_memcg: charge a kmem page
  * @memcg: memory cgroup to charge
  * @gfp: reclaim mode
- * @order: allocation order
+ * @nr_pages: number of pages to charge
  *
  * Returns 0 on success, an error code on failure.
  */
-int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp, int order)
+int __memcg_kmem_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp,
+			      unsigned int nr_pages)
 {
-	unsigned int nr_pages = 1 << order;
 	struct page_counter *counter;
 	int ret;
 
@@ -2872,7 +2872,7 @@ int __memcg_kmem_charge_page(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(memcg, gfp, order);
+		ret = __memcg_kmem_charge_memcg(memcg, gfp, 1 << order);
 		if (!ret) {
 			page->mem_cgroup = memcg;
 			__SetPageKmemcg(page);
diff --git a/mm/slab.h b/mm/slab.h
index e7da63fb8211..d96c87a30a9b 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(memcg, gfp, order);
+	ret = memcg_kmem_charge_memcg(memcg, gfp, 1 << order);
 	if (ret)
 		goto out;
 
-- 
2.21.1