mm: memcontrol: re-use global VM event enum

The current duplication is a high-maintenance mess, and it's painful to
add new items.

This increases the size of the event array, but we'll eventually want
most of the VM events tracked on a per-cgroup basis anyway.

Link: http://lkml.kernel.org/r/20170404220148.28338-2-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, 14 insertions, 31 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index bc0c16e284c0..0bb5f055bd26 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -69,20 +69,6 @@ struct mem_cgroup_reclaim_cookie {
 	unsigned int generation;
 };
 
-enum mem_cgroup_events_index {
-	MEM_CGROUP_EVENTS_PGPGIN,	/* # of pages paged in */
-	MEM_CGROUP_EVENTS_PGPGOUT,	/* # of pages paged out */
-	MEM_CGROUP_EVENTS_PGFAULT,	/* # of page-faults */
-	MEM_CGROUP_EVENTS_PGMAJFAULT,	/* # of major page-faults */
-	MEM_CGROUP_EVENTS_NSTATS,
-	/* default hierarchy events */
-	MEMCG_LOW = MEM_CGROUP_EVENTS_NSTATS,
-	MEMCG_HIGH,
-	MEMCG_MAX,
-	MEMCG_OOM,
-	MEMCG_NR_EVENTS,
-};
-
 /*
  * Per memcg event counter is incremented at every pagein/pageout. With THP,
  * it will be incremated by the number of pages. This counter is used for
@@ -106,6 +92,15 @@ struct mem_cgroup_id {
 	atomic_t ref;
 };
 
+/* Cgroup-specific events, on top of universal VM events */
+enum memcg_event_item {
+	MEMCG_LOW = NR_VM_EVENT_ITEMS,
+	MEMCG_HIGH,
+	MEMCG_MAX,
+	MEMCG_OOM,
+	MEMCG_NR_EVENTS,
+};
+
 struct mem_cgroup_stat_cpu {
 	long count[MEMCG_NR_STAT];
 	unsigned long events[MEMCG_NR_EVENTS];
@@ -288,9 +283,9 @@ static inline bool mem_cgroup_disabled(void)
 }
 
 static inline void mem_cgroup_event(struct mem_cgroup *memcg,
-				    enum mem_cgroup_events_index idx)
+				    enum memcg_event_item event)
 {
-	this_cpu_inc(memcg->stat->events[idx]);
+	this_cpu_inc(memcg->stat->events[event]);
 	cgroup_file_notify(&memcg->events_file);
 }
 
@@ -575,20 +570,8 @@ static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
 
 	rcu_read_lock();
 	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
-	if (unlikely(!memcg))
-		goto out;
-
-	switch (idx) {
-	case PGFAULT:
-		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
-		break;
-	case PGMAJFAULT:
-		this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
-		break;
-	default:
-		BUG();
-	}
-out:
+	if (likely(memcg))
+		this_cpu_inc(memcg->stat->events[idx]);
 	rcu_read_unlock();
 }
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -608,7 +591,7 @@ static inline bool mem_cgroup_disabled(void)
 }
 
 static inline void mem_cgroup_event(struct mem_cgroup *memcg,
-				    enum mem_cgroup_events_index idx)
+				    enum memcg_event_item event)
 {
 }