memcg: localize memcg_kmem_enabled() check

Move the memcg_kmem_enabled() checks into memcg kmem charge/uncharge
functions, so, the users don't have to explicitly check that condition.

This is purely code cleanup patch without any functional change.  Only
the order of checks in memcg_charge_slab() can potentially be changed
but the functionally it will be same.  This should not matter as
memcg_charge_slab() is not in the hot path.

Link: http://lkml.kernel.org/r/20190103161203.162375-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 10 insertions, 14 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index af7f18b32389..72414bb7e226 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2573,7 +2573,7 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep)
 }
 
 /**
- * memcg_kmem_charge_memcg: charge a kmem page
+ * __memcg_kmem_charge_memcg: charge a kmem page
  * @page: page to charge
  * @gfp: reclaim mode
  * @order: allocation order
@@ -2581,7 +2581,7 @@ void memcg_kmem_put_cache(struct kmem_cache *cachep)
  *
  * Returns 0 on success, an error code on failure.
  */
-int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 			    struct mem_cgroup *memcg)
 {
 	unsigned int nr_pages = 1 << order;
@@ -2604,24 +2604,24 @@ int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 }
 
 /**
- * memcg_kmem_charge: charge a kmem page to the current memory cgroup
+ * __memcg_kmem_charge: charge a kmem page to the current memory cgroup
  * @page: page to charge
  * @gfp: reclaim mode
  * @order: allocation order
  *
  * Returns 0 on success, an error code on failure.
  */
-int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 {
 	struct mem_cgroup *memcg;
 	int ret = 0;
 
-	if (mem_cgroup_disabled() || memcg_kmem_bypass())
+	if (memcg_kmem_bypass())
 		return 0;
 
 	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(page, gfp, order, memcg);
 		if (!ret)
 			__SetPageKmemcg(page);
 	}
@@ -2629,11 +2629,11 @@ int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 	return ret;
 }
 /**
- * memcg_kmem_uncharge: uncharge a kmem page
+ * __memcg_kmem_uncharge: uncharge a kmem page
  * @page: page to uncharge
  * @order: allocation order
  */
-void memcg_kmem_uncharge(struct page *page, int order)
+void __memcg_kmem_uncharge(struct page *page, int order)
 {
 	struct mem_cgroup *memcg = page->mem_cgroup;
 	unsigned int nr_pages = 1 << order;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1f9f1409df9b..034b8b6043a3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1056,7 +1056,7 @@ static __always_inline bool free_pages_prepare(struct page *page,
 	if (PageMappingFlags(page))
 		page->mapping = NULL;
 	if (memcg_kmem_enabled() && PageKmemcg(page))
-		memcg_kmem_uncharge(page, order);
+		__memcg_kmem_uncharge(page, order);
 	if (check_free)
 		bad += free_pages_check(page);
 	if (bad)
@@ -4568,7 +4568,7 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
 
 out:
 	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
-	    unlikely(memcg_kmem_charge(page, gfp_mask, order) != 0)) {
+	    unlikely(__memcg_kmem_charge(page, gfp_mask, order) != 0)) {
 		__free_pages(page, order);
 		page = NULL;
 	}
diff --git a/mm/slab.h b/mm/slab.h
index 384105318779..e5e6658eeacc 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -276,8 +276,6 @@ static __always_inline int memcg_charge_slab(struct page *page,
 					     gfp_t gfp, int order,
 					     struct kmem_cache *s)
 {
-	if (!memcg_kmem_enabled())
-		return 0;
 	if (is_root_cache(s))
 		return 0;
 	return memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
@@ -286,8 +284,6 @@ static __always_inline int memcg_charge_slab(struct page *page,
 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 						struct kmem_cache *s)
 {
-	if (!memcg_kmem_enabled())
-		return;
 	memcg_kmem_uncharge(page, order);
 }