mm: memcontrol: eliminate raw access to stat and event counters

Replace all raw 'this_cpu_' modifications of the stat and event per-cpu
counters with API functions such as mod_memcg_state().

This makes the code easier to read, but is also in preparation for the
next patch, which changes the per-cpu implementation of those counters.

Link: http://lkml.kernel.org/r/20171103153336.24044-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 20 insertions, 11 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 69966c461d1c1..2c80b69dd2661 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -272,13 +272,6 @@ static inline bool mem_cgroup_disabled(void)
 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
 }
 
-static inline void mem_cgroup_event(struct mem_cgroup *memcg,
-				    enum memcg_event_item event)
-{
-	this_cpu_inc(memcg->stat->events[event]);
-	cgroup_file_notify(&memcg->events_file);
-}
-
 bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);
 
 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
@@ -627,15 +620,23 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 						gfp_t gfp_mask,
 						unsigned long *total_scanned);
 
+/* idx can be of type enum memcg_event_item or vm_event_item */
+static inline void __count_memcg_events(struct mem_cgroup *memcg,
+					int idx, unsigned long count)
+{
+	if (!mem_cgroup_disabled())
+		__this_cpu_add(memcg->stat->events[idx], count);
+}
+
+/* idx can be of type enum memcg_event_item or vm_event_item */
 static inline void count_memcg_events(struct mem_cgroup *memcg,
-				      enum vm_event_item idx,
-				      unsigned long count)
+				      int idx, unsigned long count)
 {
 	if (!mem_cgroup_disabled())
 		this_cpu_add(memcg->stat->events[idx], count);
 }
 
-/* idx can be of type enum memcg_stat_item or node_stat_item */
+/* idx can be of type enum memcg_event_item or vm_event_item */
 static inline void count_memcg_page_event(struct page *page,
 					  int idx)
 {
@@ -654,12 +655,20 @@ static inline void count_memcg_event_mm(struct mm_struct *mm,
 	rcu_read_lock();
 	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 	if (likely(memcg)) {
-		this_cpu_inc(memcg->stat->events[idx]);
+		count_memcg_events(memcg, idx, 1);
 		if (idx == OOM_KILL)
 			cgroup_file_notify(&memcg->events_file);
 	}
 	rcu_read_unlock();
 }
+
+static inline void mem_cgroup_event(struct mem_cgroup *memcg,
+				    enum memcg_event_item event)
+{
+	count_memcg_events(memcg, event, 1);
+	cgroup_file_notify(&memcg->events_file);
+}
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void mem_cgroup_split_huge_fixup(struct page *head);
 #endif