mm: memcontrol: use generic mod_memcg_page_state for kmem pages

The kmem-specific functions do the same thing.  Switch and drop.

Link: http://lkml.kernel.org/r/20170530181724.27197-5-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -929,19 +929,6 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
 	return memcg ? memcg->kmemcg_id : -1;
 }
 
-/**
- * memcg_kmem_update_page_stat - update kmem page state statistics
- * @page: the page
- * @idx: page state item to account
- * @val: number of pages (positive or negative)
- */
-static inline void memcg_kmem_update_page_stat(struct page *page,
-				enum memcg_stat_item idx, int val)
-{
-	if (memcg_kmem_enabled() && page->mem_cgroup)
-		this_cpu_add(page->mem_cgroup->stat->count[idx], val);
-}
-
 #else
 #define for_each_memcg_cache_index(_idx)	\
 	for (; NULL; )
@@ -964,10 +951,6 @@ static inline void memcg_put_cache_ids(void)
 {
 }
 
-static inline void memcg_kmem_update_page_stat(struct page *page,
-				enum memcg_stat_item idx, int val)
-{
-}
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 
 #endif /* _LINUX_MEMCONTROL_H */

kernel/fork.c

@@ -326,7 +326,7 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
 		}
 
 		/* All stack pages belong to the same memcg. */
-		memcg_kmem_update_page_stat(vm->pages[0], MEMCG_KERNEL_STACK_KB,
+		mod_memcg_page_state(vm->pages[0], MEMCG_KERNEL_STACK_KB,
 				     account * (THREAD_SIZE / 1024));
 	} else {
 		/*
@@ -338,7 +338,7 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
 		mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB,
 				    THREAD_SIZE / 1024 * account);
 
-		memcg_kmem_update_page_stat(first_page, MEMCG_KERNEL_STACK_KB,
+		mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB,
 				     account * (THREAD_SIZE / 1024));
 	}
 }

mm/slab.h

@@ -285,7 +285,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 	if (ret)
 		return ret;
 
-	memcg_kmem_update_page_stat(page,
+	mod_memcg_page_state(page,
 			     (s->flags & SLAB_RECLAIM_ACCOUNT) ?
 			     NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
 			     1 << order);
@@ -298,7 +298,7 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 	if (!memcg_kmem_enabled())
 		return;
 
-	memcg_kmem_update_page_stat(page,
+	mod_memcg_page_state(page,
 			     (s->flags & SLAB_RECLAIM_ACCOUNT) ?
 			     NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
 			     -(1 << order));