mm: memcontrol: cleanup kmem charge functions

 - Handle memcg_kmem_enabled check out to the caller. This reduces the
   number of function definitions making the code easier to follow. At
   the same time it doesn't result in code bloat, because all of these
   functions are used only in one or two places.

 - Move __GFP_ACCOUNT check to the caller as well so that one wouldn't
   have to dive deep into memcg implementation to see which allocations
   are charged and which are not.

 - Refresh comments.

Link: http://lkml.kernel.org/r/52882a28b542c1979fd9a033b4dc8637fc347399.1464079537.git.vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 96 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 56e6069d2452..71aff733a497 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -749,6 +749,13 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 }
 #endif
 
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
+void memcg_kmem_put_cache(struct kmem_cache *cachep);
+int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+			    struct mem_cgroup *memcg);
+int memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
+void memcg_kmem_uncharge(struct page *page, int order);
+
 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 extern struct static_key_false memcg_kmem_enabled_key;
 
@@ -770,22 +777,6 @@ static inline bool memcg_kmem_enabled(void)
 }
 
 /*
- * In general, we'll do everything in our power to not incur in any overhead
- * for non-memcg users for the kmem functions. Not even a function call, if we
- * can avoid it.
- *
- * Therefore, we'll inline all those functions so that in the best case, we'll
- * see that kmemcg is off for everybody and proceed quickly.  If it is on,
- * we'll still do most of the flag checking inline. We check a lot of
- * conditions, but because they are pretty simple, they are expected to be
- * fast.
- */
-int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
-			      struct mem_cgroup *memcg);
-int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
-void __memcg_kmem_uncharge(struct page *page, int order);
-
-/*
  * helper for accessing a memcg's index. It will be used as an index in the
  * child cache array in kmem_cache, and also to derive its name. This function
  * will return -1 when this is not a kmem-limited memcg.
@@ -795,67 +786,6 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
 	return memcg ? memcg->kmemcg_id : -1;
 }
 
-struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
-void __memcg_kmem_put_cache(struct kmem_cache *cachep);
-
-static inline bool __memcg_kmem_bypass(void)
-{
-	if (!memcg_kmem_enabled())
-		return true;
-	if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
-		return true;
-	return false;
-}
-
-/**
- * memcg_kmem_charge: charge a kmem page
- * @page: page to charge
- * @gfp: reclaim mode
- * @order: allocation order
- *
- * Returns 0 on success, an error code on failure.
- */
-static __always_inline int memcg_kmem_charge(struct page *page,
-					     gfp_t gfp, int order)
-{
-	if (__memcg_kmem_bypass())
-		return 0;
-	if (!(gfp & __GFP_ACCOUNT))
-		return 0;
-	return __memcg_kmem_charge(page, gfp, order);
-}
-
-/**
- * memcg_kmem_uncharge: uncharge a kmem page
- * @page: page to uncharge
- * @order: allocation order
- */
-static __always_inline void memcg_kmem_uncharge(struct page *page, int order)
-{
-	if (memcg_kmem_enabled())
-		__memcg_kmem_uncharge(page, order);
-}
-
-/**
- * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
- * @cachep: the original global kmem cache
- *
- * All memory allocated from a per-memcg cache is charged to the owner memcg.
- */
-static __always_inline struct kmem_cache *
-memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
-{
-	if (__memcg_kmem_bypass())
-		return cachep;
-	return __memcg_kmem_get_cache(cachep, gfp);
-}
-
-static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
-{
-	if (memcg_kmem_enabled())
-		__memcg_kmem_put_cache(cachep);
-}
-
 /**
  * memcg_kmem_update_page_stat - update kmem page state statistics
  * @page: the page
@@ -878,15 +808,6 @@ static inline bool memcg_kmem_enabled(void)
 	return false;
 }
 
-static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
-{
-	return 0;
-}
-
-static inline void memcg_kmem_uncharge(struct page *page, int order)
-{
-}
-
 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 {
 	return -1;
@@ -900,16 +821,6 @@ static inline void memcg_put_cache_ids(void)
 {
 }
 
-static inline struct kmem_cache *
-memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
-{
-	return cachep;
-}
-
-static inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
-{
-}
-
 static inline void memcg_kmem_update_page_stat(struct page *page,
 				enum mem_cgroup_stat_index idx, int val)
 {