mm: memcontrol: remove double kmem page_counter init

The kmem page_counter's limit is initialized to PAGE_COUNTER_MAX inside
mem_cgroup_css_online().  There is no need to repeat this from
memcg_propagate_kmem().

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.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 f21f29cd14f9a5d93baebb88ccaf2e58d03c2611..71dced17b16deb2192ab8e1a36ccee3e997093de 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2861,8 +2861,7 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-static int memcg_activate_kmem(struct mem_cgroup *memcg,
-                              unsigned long nr_pages)
+static int memcg_activate_kmem(struct mem_cgroup *memcg)
 {
        int err = 0;
        int memcg_id;
@@ -2897,13 +2896,6 @@ static int memcg_activate_kmem(struct mem_cgroup *memcg,
                goto out;
        }
 
-       /*
-        * We couldn't have accounted to this cgroup, because it hasn't got
-        * activated yet, so this should succeed.
-        */
-       err = page_counter_limit(&memcg->kmem, nr_pages);
-       VM_BUG_ON(err);
-
        static_branch_inc(&memcg_kmem_enabled_key);
        /*
         * A memory cgroup is considered kmem-active as soon as it gets
@@ -2924,10 +2916,14 @@ static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
        int ret;
 
        mutex_lock(&memcg_limit_mutex);
-       if (!memcg_kmem_is_active(memcg))
-               ret = memcg_activate_kmem(memcg, limit);
-       else
-               ret = page_counter_limit(&memcg->kmem, limit);
+       /* Top-level cgroup doesn't propagate from root */
+       if (!memcg_kmem_is_active(memcg)) {
+               ret = memcg_activate_kmem(memcg);
+               if (ret)
+                       goto out;
+       }
+       ret = page_counter_limit(&memcg->kmem, limit);
+out:
        mutex_unlock(&memcg_limit_mutex);
        return ret;
 }
@@ -2946,7 +2942,7 @@ static int memcg_propagate_kmem(struct mem_cgroup *memcg)
         * after this point, because it has at least one child already.
         */
        if (memcg_kmem_is_active(parent))
-               ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
+               ret = memcg_activate_kmem(memcg);
        mutex_unlock(&memcg_limit_mutex);
        return ret;
 }