mm: memcontrol: clean up memory.events counting function

We only ever count single events, drop the @nr parameter.  Rename the
function accordingly.  Remove low-information kerneldoc.

Link: http://lkml.kernel.org/r/20170404220148.28338-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 108d5b0..1ffa3ad 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1825,7 +1825,7 @@
 	do {
 		if (page_counter_read(&memcg->memory) <= memcg->high)
 			continue;
-		mem_cgroup_events(memcg, MEMCG_HIGH, 1);
+		mem_cgroup_event(memcg, MEMCG_HIGH);
 		try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
 	} while ((memcg = parent_mem_cgroup(memcg)));
 }
@@ -1916,7 +1916,7 @@
 	if (!gfpflags_allow_blocking(gfp_mask))
 		goto nomem;
 
-	mem_cgroup_events(mem_over_limit, MEMCG_MAX, 1);
+	mem_cgroup_event(mem_over_limit, MEMCG_MAX);
 
 	nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
 						    gfp_mask, may_swap);
@@ -1959,7 +1959,7 @@
 	if (fatal_signal_pending(current))
 		goto force;
 
-	mem_cgroup_events(mem_over_limit, MEMCG_OOM, 1);
+	mem_cgroup_event(mem_over_limit, MEMCG_OOM);
 
 	mem_cgroup_oom(mem_over_limit, gfp_mask,
 		       get_order(nr_pages * PAGE_SIZE));
@@ -5142,7 +5142,7 @@
 			continue;
 		}
 
-		mem_cgroup_events(memcg, MEMCG_OOM, 1);
+		mem_cgroup_event(memcg, MEMCG_OOM);
 		if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
 			break;
 	}