memcg: revise the position of threshold index while unregistering event

Index current_threshold should point to threshold just below or equal to
usage.  See below: http://www.spinics.net/lists/cgroups/msg00844.html

Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ed0d707094d82c18e3f17b91e2bcfceafe138332..9a6d7b87640d4ca107e9b0b6154319c4c18830f9 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4675,7 +4675,7 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
                        continue;
 
                new->entries[j] = thresholds->primary->entries[i];
-               if (new->entries[j].threshold < usage) {
+               if (new->entries[j].threshold <= usage) {
                        /*
                         * new->current_threshold will not be used
                         * until rcu_assign_pointer(), so it's safe to increment